Darstellung und Schwingungsspektren der 35Cl/37Cl-markierten Fluoro-Chloro-Platinate(IV) / Preparation and Vibrational Spectra of 35Cl/37Cl Labelled Fluoro-Chloro-Platinates(IV)

All components of the two series Cs2[PtF„35Cl6-n] and Cs2[PtFn 37Cl6-n], including the pairs of geometric isomers for n = 2,3, 4, have been prepared and isolated by ion exchange chromatography on DEAE cellulose. The highly resolved low temperature (80 K) IR and Raman spectra of the pure isotopomers show distinctive isotopic shifts for different vibrational modes up to 10 cm-1. The excellent agreement of the observed values with Teller-Redlich calculations verifies the assignment of all stretching and especially of the narrow deformation bands. For transcomplexes containing 35Cl-Pt-37Cl axes, the lowered symmetry affects the restriction of the rule of mutual exclusion

closo-Halogenohydrohexaborate, I Darstellung der reinen closo-Halogenohydrohexaborate XnB6H6-n 2-, n = 1— 6, X = Cl, Br, I, einschlieftlich der Stereoisomeren / closo-Halogenohydrohexaborate, I Preparation of the Pure closo-Halogenohydrohexaborates XnB6H6-n 2-, n = 1— 6. X = Cl, Br, I, Including the Stereoisomers

Through carefully controlled treatment of Na2B6H6 with halogens in aqueous alkaline solution, or with halogenosuccinimides, mixtures of the halogenohydrohexaborates XnB6H6-n 2-, X = Cl, Br, I, n = 1-6, are formed. In der cases with X = Cl, Br, for n = 2-4 both stereoisomers are generated simultaneously in different amounts, whereas with X = I only the trans/mer compounds are formed. All species including the pure isomers have been separated by ion exchange chromatography on diethylaminoethyl cellulose. The composition has been confirmed by chemical analysis. The colourless crystalline tetrabutylammonium salts are fairly stable at room temperature

Darstellung, Schwingungsspektren und Normalkoordinatenanalyse der 10B-und 11B-Isotopomeren von [B2(NCS)6]2- sowie Kristallstruktur von (Ph3P=N=PPh3)2[B2(NCS)6] / Preparation, Vibrational Spectra and Normal Coordinate Analysis of the 10B and 11B Isotopomers of [B2(NCS)6]2- and Crystal Structure of (Ph3P=N=PPh3)2[B2(NCS)6]

By reaction of [B6H6]2- with a solution of (SCN)2 in dichloromethane in the presence of solid KOH the hexaisothiocyanatodiborate anion [B2(NCS)6]2- is formed and can be isolated by fractionated crystallization. The crystal structure of (PNP)2[B2(NCS)6] has been determined by single crystal X-ray diffraction analysis; triclinic space group P1̄ with a=12,282(5), b=12,416(5), c=14,155(5)Å, a=68,36(5), β=70,59(5), γ=80,93(5)°.The [B2(NCS)6]2- anion reveals a staggered conformation with nearly local D3d symmetry and a B-B bond length of 1,73(2) Å. Using the crystallographic data a normal coordinate analysis has been performed. With a set of 12 force constants (e.g. fd(BB)=3,62, fd(BN)=4,21 mdyn/Å) a good agreement between observed and calculated frequencies for the 10B and 11B isotopomers has been achieved. The potential energy distribution on the force constants reveals strong vibrational couplings within the B2N6 framework.

Darstellung, Charakterisierung und Normalkoordinatenanalyse von gemischtvalentem Dodekabromotriplatinat(IV,II,IV) [Pt3Br12]2- und Kristallstruktur von (Ph3P=N=PPh3)2[Pt3Br12] · 2 CH2C12 / Preparation, Characterization and Normal Coordinate Analysis of the Mixed Valence Dodecabromotriplatinat(IV,II,IV) [Pt3Br12]2- and Crystal Structure of (Ph3P=N=PPh3)2[Pt3Br12] · 2CH2Cl2

Heating a mixture (2:1) of the tetrabutylammonium salts (TBA)2[PtBr6] and (TBA)2[PtBr4] with trifluoroacetic acid leads to the mixed valence dodecabromotriplatinate(IV,II,IV) (TBA)2[Pt3Br12]. The X-ray structure determination of (Ph3P=N=PPh3)2[Pt3Br12] · 2 CH2Cl2 (triclinic, PĪ, Z = 1) shows trinuclear groups with nearly D2h symmetry for the anions, formed of two PtBr6 octahedra and one planar PtBr4 group sharing edges. Using the structural data a normal coordinate analysis based on a general valence force field for [Pt3Br12]2- has been performed, which gives good agreement of the calculated frequencies with the bands observed in the IR and Raman spectra.

Schwingungsspektren und Normalkoordinatenanalyse der Bromo-Iodo-Osmate(IV), [OsBrnI6-n]2-, n = 0-6 / Vibrational Spectra and Normal Coordinate Analysis of Bromo-Iodo-Osmates(IV), [OsBrnI6-n]2-, n = 0-6

The IR and Raman spectra of the ten bromo-iodo-osmates(IV) [OsBrnI6-n]2-, n = 0-6, including the geometrical isomers for n = 2, 3, 4, have been recorded at low temperature. The vibrational spectra are completely assigned according to point groups Oh, D4h, C4v, C3v, and C2v, as supported by normal coordinate analyses based on a general valence force field. Due to the different trans-influences Br<I in asymmetric axes Br′–Os–I′, the Os–I′ bonds are strengthened and the Os–Br′ bonds are weakened, as indicated by valence force constants, for Os–I′ on average 4% higher and for Os–Br′ 4% lower, as compared with the values calculated for symmetric I–Os–I and Br–Os–Br axes, respectively.

Darstellung, 11 B-NMR-, Schwingungsspektren und Kristallstruktur von Bis(tetraphenylphosphonium)-2-[2-(2-pyridyl-amino)-pyrid-5-yl]-closo-decaborat, [P(C6H5)4]2[2-{2-(2-(C5H4N)-NH)-(C5H3N)-5}B10H9] / Preparation, 11B NMR, Vibrational Sprectra and Crystal Structure of Bis(tetraphenylphosphonium) 2-[2-(2-Pyridyl-amino)-pyrid-5-yl]-closo-decaborate, [P(C6H5)4]2 [2-{2-(2-(C5H4N)-NH)-(C5H3N)-5}B10H9]

By reaction of [N(C4H9)4]2[B10H10] with 2, 2′-(C5H5N)2NH at 160 °C the 2-[2-(2-pyridylamino)- pyrid-5-yl]-closo-decaborate anion [2-{2-(2-(C5H4N)-NH)-(C5H3N)-5 }B10H9]2− is obtained which can be separated from excess [B10H10]2− by ion exchange chromatography on diethylaminoethyl(DEAE) cellulose. The crystal structure of [P(C6H5)4]2[2-{2-(2-(C5H4N)- NH)-(C5H3N)-5 }B10H9] has been determinated by single crystal X-ray diffraction analysis: monoclinic, space group P21/n with a = 11.435(3), b = 22.923(2), c = 20.094(4) Å, β = 95,27(2)°, Z = 4. By influence of the substituent the B10 cage is strongly distorted with B-B distances ranging from 1.522 to 2.188 Å. The 11B NMR spectrum reveals the feature (2:1:7) of a B10 cage with the substituent in the 2 position with a downfield shift of the ipso B atom at −20.2 ppm. The IR and Raman spectra exhibit characteristic BH stretching vibrations between 2416 and 2499 cm −1 and the (C-C) and (C-N) stretching vibrations in the range of 1306 to 1584 cm −1 .

Notizen: Darstellung und Eigenschaften von trans-Diiodo-tetrakis(pyridin)osmium(II)/Preparation and Properties of /trans-Diiodo-tetrakis(pyridine)osmium (II)

K2[OsI6] reacts with pyridine and glycerin to give dark red crystals of trans-[OsI2(py)4], soluble in organic solvents, insoluble in water, and sublimable in vacuum at 360 °C. The structure is established by vibrational and mass spectra. From solutions in non-polar solvents with gaseous HX (X = Cl, Br) adducts of type trans-[OsI2(py)4] ·2 HX are precipitated, which are soluble in water with blue colour.

Normalkoordinatenanalyse der 35Cl/37Cl-markierten Fluoro-Chloro-Platinate(IV), Cs2[PtFnCl6-n], n = 0-6 / Normal Coordinate Analysis of the 35Cl/37Cl Labelled Fluoro-Chloro-Platinates(IV), Cs2[PtF„Cl6-n, n = 0 – 6

Normal coordinate analyses for all compounds of the two series Cs2[PtF„35Cl6-n] and Cs2[PtF„37Cl6-n], n = 0-6, including the geometric isomers for n = 2, 3, 4 have been performed, based on a general valence force field. The excellent agreement of calculated and observed frequencies confirms the assignments of the vibrational spectra. Due to the stronger trans influence of Cl compared to F in all asymmetric F–Pt–Cl axes the Pt–Cl bonds are strengthened and the Pt–F bonds are weakened, as indicated by valence force constants for Pt–Cl approximately 20% higher, for Pt–F 20% lower, compared with the values calculated for symmetric Cl–Pt–Cl and F–Pt–F axes, respectively. The contour of the Raman line ν2 (Eg, Oh) of Cs2[PtCl6] is explained by the superposition of the calculated spectra for the six most frequent isotopomers Cs2[Pt35Cln 37Cl6-n] present in mixtures with natural abundance of Cl isotopes (75,53% 35Cl, 24,47% 37Cl) by statistical distribution on the octahedron sites.

Schwingungsspektren und Normalkoordinatenanalyse der 35Cl/37Cl-isotopierten Chloro-Iodo-Osmate(IV), [OsClnI6-n]2-, n = 0-6 / Vibrational Spectra and Normal Coordinate Analysis of the 35Cl/37Cl Labelled Chloro-Iodo-Osmates(IV), [OsClnI6-n]2-, n = 0-6

All components of the two series [Os35ClnI6-n]2- and [Os37ClnI6-n]2-, n = 0-6, including the pairs of geometric isomers for n = 2, 3, 4, have been prepared and isolated by ion exchange chromatography on DEAE cellulose. The highly resolved low temperature (80 K) IR and Raman spectra of the pure isotopomers show distinct isotopic shifts for different vibrational modes up to 10 cm-1. Normal coordinate analyses have been performed, based on a general valence force field. Due to the stronger trans influence of I as compared to Cl in all asymmetric Cl˙—Os—I′ axes the Os—I′ bonds are strengthened and the Os—Cl˙ bonds are weakened, as indicated by valence force constants for Os—I′ approximately 9% higher, for Os—Cl˙ 7% lower, as compared with the values calculated for symmetric axes.

Kristallstruktur, Schwingungsspektren und Normalkoordinatenanalyse von trans-(Et4N)[OsF4Cl2] / Crystal Structure, Vibrational Spectra and Normal Coordinate Analysis of trans-(Et4N)[OsF4Cl2]

By careful oxidation of trans-tetrafluorodichloroosmate(IV) with PbO2/trifluoroacetic acid in dichloromethane the corresponding osmium(V) complex anion rran5 -[OsF4Cl2]- is for­ med. The X-ray structure determination on a single crystal has been performed of trans-(Et4N)[OsF4Cl2] (triclinic, space group P1̄a = 7.190(5), b = 7.205(5), c = 7.732(5) Å, a = 71.28(1), β = 71.32(1), 7 = 70.76(1)°, Z = 1). Based on the molecular parameters of the X-ray determination the IR and Raman spectra of the complex have been assigned by normal coordi­ nate analysis. The valence force constants are: fd(OsCl) = 2.13 and fd(OsF) = 3.81 mdyn/Å.

Darstellung und Schwingungsspektren von Fluoro-Chloro-Osmaten(IV) einschließlich der Stereoisomeren/ Preparation and Vibrational Spectra of Fluoro-Chloro-Osmates(IV) Including Stereoisomers

The stepwise replacement of ligands in [OsCl6]2- by oxidation with BrF3 generates the mixed complexes [OsFnCl6-n]2-, n = 1 - 5, of which the species with n = 2,3,4 are cw-configurated. Due to the stronger trans-effect of Cl compared to F on treatment of [OsF5Cl]2- and cis-[OsF4Cl2]2- with Cl- the trans-isomers are formed stereospecifically. The pure fluoro-chloro-osmates(IV) are separated by ion exchange chromatography on diethylaminoethylcellulose. From the pairs of stereoisomers the cis-compounds are always first eluted, whereas the trans-complexes are moving faster in an electric field by 3 to 5% . The vibrational spectra of octahedral mixed ligand complexes are generally discussed according to point groups Oh, D4h, C4v, C3v and C2v. For the fluoro-chloroosmates(IV) all stretching and deformation bands are assigned. They are observed in the characteristic regions; ν(OsF): 625-490 > ν(OsCl): 360-300 > δ (FOsF): 275-210 > δ (FOsCl) > δ (ClOsCl): 190-150 > νL: < 100 cm -1.

Kristallstrukturen von (n-Bu4N)[B6Cl6], (n-Bu4N)[B6Br6] und (Ph3P=N=PPh3)[B6I6] sowie Schwingungsspektren und Normalkoordinatenanalyse der Hexahalogeno-c/osö-Hexaboratradikalanionen [B6X6]-, X = Cl, Br, I / Crystal Structures of (n-Bu4N)[B6Cl6], (n-Bu4N)[B6Br6], and (Ph3P=N=PPh3)[B6I6], and Vibrational Spectra and Normal Coordinate Analysis of the Hexahalogeno-closo-hexaborate Radical Anions [B6X6]- , X = Cl, Br, I

Oxidation of hexahalogeno-closo-hexaborates [B6X6]2-, X = Cl, Br, I, with (NH4)2[Ce(NO3)6] in ethanol yields coloured radical ions [B6X6]-. X-ray structure determina­ tions have been performed on single crystals of (n-Bu4N)[B6Cl6] (1) (monoclinic, space group P21/c,a = 13.144(2),6 = 12.594(2),c = 17.688(5) Å, β = 107.29(2)°,Z=4),(n-Bu4N)[B6Br6] (2) (monoclinic, space group P21/c, a = 13.529(5), b = 13.096(5), c = 17.863(5) Å, β = 107.20(5)°, Z = 4) and (Ph3P=N=PPh3)[B6I6] (3) (triclinic, space group P1̄, a = 9.3137(8), b = 10.6988(10), c = 11.8760 Å , a = 102.220(7), β = 99.34J(8), 7 = 96.030(7)°, Z = 1). The average B-B distances are nearly equal (1.733 Å (1), 1.728 Å (2), 1.728 Å (3)) while the B-X distances increase (1.762 Å (1), 1.912 Å (2), 2.120 Å (3)). Using the molecular parameters, normal coordinate analyses have been performed and a good agreement of observed and calculated frequencies of 10B and 11B labelled derivatives has been achieved. The valence force constants fd(BB) and fd(BX) of [B6X6]- are 1.17 and 4.17 (X = Cl), 1.18 and 3.34 (Br) and 1.18 and 2.60 mdyn/Å (I), respectively.

Darstellung, Schwingungsspektren und Normalkoordinationsanalyse der D- und 13C-Isotopomeren des Methylpentahydro-closo-hexaborats [B6H5(CH3)]2- sowie Kristallstruktur von [P(C6H5)4][B6H6(CH3)] / Preparation, Vibrational Spectra and Normal Coordinate Analysis of the D and 13C Isotopomeres of the Methylpentahydro-closo-hexaborate [B6H5(CH3)]2- and the Crystal Structure of [P(C6H5)4][B6H6(CH3)]

The crystal structure of [P(C6H5)4][B6H6(CH3)] has been determined by single crystal X-ray diffraction analysis; triclinic space group P 1̄ with a = 7.408(2), b = 11.887(3), c = 14.4486(9) Å , α = 80.013(12), β = 79.421(10), γ = 88.85(2)°. The additional H atom could be refined with B - H distances between 1.21 and 1.31 Å above one of the facettes of the B6 octahedron adjacent to the methyl group. The IR and Raman spectra of the ueprotonated Cs salts of the six isotopomers [B6H5(CH3)]2-, [B6H5(CD3)]2-, [B6H5(13CH3)]2-, [B6D5(CH3)]2-, [B6D5(CD3)]2- and [B6D5(13CH3)]2- exhibit characteristic shifts of their vibration bands. Using the crystallographic data a normal coordinate analysis has been performed, based on a general valence force field. With a set of 14 force constants (e.g. fd(BB ) = 1.80, fd(BC ) = 3.70, fd(BH ) = 3.17, fd(CH ) = 4.62 mdyn/Å) good agreement between observed and calculated frequencies o f all D and 13C isotopically labeled derivatives has been achieved. The potential energy distribution on the force constants reveals strong vibrational couplings of the boron cage with the substituents. The B - C stretching vibration o f the CH3 group is observed in the region 1142-1153 cm-1, for the CD3 substituent at higher frequencies of 1168-1179 cm-1.

Darstellung, 11B-NMR- und Schwingungsspektren der oktaedrischen closo-Boratanionen B6X6 2-; X = H, Cl, Br, I

On treatment of Na2B6H6 with halogens in aqueous alkaline solution, the hexahalogenoborates B6X6 2-, X = Cl, Br, I, are formed. Their octahedral structure is proved by 11B NMR spectroscopy. The chemical shifts in relation to BF3 · OEt2 increase within the series H (-13.5) < Cl (-17.4) < Br (-18.5) < I (- 27.5 ppm ). The IR and Raman spectra are assigned according to point group Oh. The internal vibrations of the B6-cage, observed in the range 750-1250 cm-1 at nearly unchanged positions, are distinguishable from vibrations mainly originating from motions of the X6-shell against the rigid B6-cluster.

Halogenokomplexe von Osmium(III) mit Pyridin, Pyrazin, Pyrimidin und einigen Methylhomologen

The preparation of mer-[OsX3B3], X = Cl, Br, I; B = pyridine, 3-resp. 4-picoline, pyrimidine, pyrazine, methylpyrazine, and the chromatographic isolation of four basemixed stereoisomers mer-[OsX3(py)n(mepyz)3-n], n= 1, 2, as solid crystalline products is described. Mass spectra and ligand exchange reactions confirm the structure of these complexes. The UV and IR spectra are discussed.

Darstellung und Charakterisierung von Tetrabutylammonium-Tetraiodooxotechnetat(V), (TBA) [TcOI4] / Preparation and Characterization of Tetrabutylammonium Tetraiodooxotechnetate(V), (TBA)[TcOI4]

Pure (TBA)[TcOI4] is prepared from (TBA)[TcOCl4] by ligand exchange reaction with Nal in acetone. The vibrational spectra indicate C4v symmetry for the complex ion. On excitation with the 514.5 nm line of an Ar-laser a resonance Raman spectrum is obtained showing v(TcO) = 996 cm-1 and four of its overtones, symmetrically surrounded by groups of bands arising as well from the sums as from the differences of frequencies with the other fundamentals. In contrast to the ligand exchange reaction the reduction of Tc04- with conc. HI yields products always contaminated with polyiodides. The extremely strong Raman scatterer (TBA)l3 is detected by a characteristic doublet at 111 and 116 cm-1 and even small amounts of it cover the Raman spectrum of (TBA)[TcOI4].

Darstellung, 11B-und 19F-NMR-Spektren des Monofluoropentaiodo- closo-hexaboratanions sowie Kristallstruktur von (CH2Py2)[B6FI5]/ Synthesis, 11B and 19F NMR Spectra of the Monofluoropentaiodo-closo-hexaborate Anion and the Crystal Structure of (CH2Py2)[B6FI5]

By reaction of closo-[B6H5F]2- in alkaline solution with excess iodine the monofluoropentaiodo- closo-hexaborate anion [B6FI5]2- is formed in good yield. The crystal structure of (CH2Py2)[B6FI5] has been determined by single crystal X-ray diffraction analysis (orthorhombic, space group Pnma, a = 13.803(2), b = 11.759(2), c = 13.936(2) Å, Z = 4). The B-F-bond length is 1.41 Å, the B-I distances range from 2.13 to 2.17 Å, the B-B distances from 1.69 to 1.76 A. According to the C4v point symmetry the 11B NMR spectrum of the anion exhibits three singlets at +3.8,-30.1 and-33.3 ppm with the intensity ratio 1:4:1, the 19F NMR spectrum one quartet at -247.6 ppm with the coupling constant 1J (19F, 11B) = 54 Hz.

Darstellung und Charakterisierung von Dekachlorodiiridat(IV), [Ir2Cl10]2-, und Normalkoordinatenanalyse an Dioktaederkomplexen des Typs [M2X10]2-, M = Re, Os, Ir, Pt; X = Cl, Br / Preparation and Characterization of Decachlorodiiridate(IV), [Ir2Cl10]2-, and Normal Coordinate Analysis of Bioctahedral Complexes [M2X10]2-, M = Re, Os, Ir, Pt; X = Cl, Br

On heating the tetraethylammonium salt of [IrCl6]2- with trifluoroacetic acid the edge sharing bioctahedral anion [Ir2Cl10]2- is formed, the IR and Raman spectra of which are assigned according to point group D2h. Normal coordinate analyses, based on a general valence force field, for [M2X10]2-, M = Re, Os, Ir, Pt; X = Cl, Br have been performed, resulting in a good agreement of the calculated frequencies with the bands observed in the IR and Raman spectra. Due to the stronger bonding of the terminal as compared to the bridging ligands, the valence force constants fd(MXt) are significantly higher than fd(MXb).

Darstellung und Schwingungsspektren von Fluoro-Chloro-Osmaten(V)/ Preparation and Vibrational Spectra of Fluoro-Chloro-Osm ates(V)

By oxidation of the pure fluoro-chloro-osmates(IV ) with BrF3 in dichlorom ethane the mixed pentavalent complexes [OsF5Cl]-, cis-[OsF4Cl2]-, fac-[OsF3Cl3]- and cis-[OsF2Cl4]- are formed without replacement of ligands. Trans-[OsF4Cl2]- and trans-[OsF2Cl4]- are generated from the corresponding osmates(IV) by oxidation with PbO2 in dichloromethane under addition of trifluoroacetic acid. The vibrational spectra o f the mixed ligand complexes are assigned according to point groups D4h, C4v, C3v and C2v. The increased bond strength com pared with the corresponding Os(IV ) complexes is indicated by a significant shift to higher energy by about 5 -15% . The Os -Cl stretching vibration of [OsF5Cl]- and also the symmetric ClOsCl of trans-[OsF4Cl2]- is split by the isotopes 35Cl and 37Cl, showing two and three well resolved sharp Raman lines in the expected ratio of intensities, respectively.

Darstellung und Kristallstruktur von /wer-[Os(NCS)3Py3] / Synthesis and Crystal Structure of mer-[Os(NCS)3Py3]

By reaction of K3[Os(NCS)3(SCN)3] with pyridine and glycerine the complex mer- [Os(NCS)3Py3] is formed. The X-ray structure determination on a single crystal (monoclinic, space group C2/c, a = 18.6156(12), b = 15.9448(7), c = 19.555(2) Å, β = 94.657(7)°, Z = 8) reveals that the nearly linear thiocyanate groups are exclusively bonded via the N atoms with Os-N-C angles ranging from 169.9° to 177.7°.

195Pt- und 19F-NMR-Spektren der Fluoro-Chloro-Platinate(IV), [PtFnCl6-n]2-, n = 0-6 / 195Pt and 19F NMR Spectra of the Fluoro-Chloro-Platinates(IV), [PtFnCl6-n]2-, n = 0-6

The 10 complex ions of the system [PtFnCl6-n]2-, n = 0—6, including the three pairs of stereoisomers for n = 2, 3, 4 have been characterized by 195Pt and 19F NMR spectroscopy in CD2Cl2 solution. A wide range from 4731 ([PtCl6]2-) to 11816 ppm ([PtF6]2-) is covered by the clearly separated 195Pt resonances. The chemical shift δ(195Pt) depends nearly linearly on the sum of the electronegativities of the ligands. In accordance with increasing deshielding of the 195Pt nucleus by increasing coordination with F ligands an averaged major downfield shift of 1181 ppm per substitution of Cl by F is observed, while a minor averaged value of 354 ppm downfield is found for the trans/mer isomers in comparison to the related cis/fac isomers. Coupling with 19F results in characteristic 195Pt multiplets, with 1J(PtF) coupling constants for symmetric F—Pt—F axes of averaged 1890 Hz about 31% larger than 1J(PtF•) for asymmetric F•—Pt—Cl′ axes with averaged 1296 Hz. The data reflect the trans influence of the ligands. Highly resolved and expanded 195Pt spectra reveal clearly separated isotopomer signals with intensities according to the expected statistical ratios given by the natural abundance of 35Cl and 37Cl. For [Pt35Cln 37Cl6-n]2- five distinct signals related to n = 6-2 with 0,18 ppm highfield shift per 37Cl atom have been reliably assigned. Resolved isotopomer peaks have also been observed for mer-[PtF3 35Cl3]2-/mer-[PtF3 35Cl2 37Cl]2- with 0,21 ppm and for [PtF5 35Cl]2/[PtF5 37Cl]2- with 0,32 ppm highfield shift per 37Cl atom, respectively. The 19F resonances of symmetric axes appear at higher field, in the range from —357 to —382 ppm, than those of asymmetric axes, from —266 to —287 ppm. Under high resolution compounds with inequivalent F nuclei show multiplets originating from homonuclear 2J(FF•) couplings of about 40 Hz.

Darstellung und Schwingungsspektren von Fluoro-Chloro- Platinaten(IV) einschließlich der Stereoisomeren / Preparation and Vibrational Spectra of Fluoro-Chloro-Platinates(IV) Including Stereoisomers

The reaction of [PtCI6]2- with BrF3 generates the mixed complexes [PtFnC6-n]2- , n = 1- 5, of which the species with n = 2. 3, 4 are cis-configurated. Due to the stronger trans-effect of Cl compared to F, on treatment of [PtF5Cl]2- and cis-[PtF4Cl2]2- with Cl- the trans-isomers are formed stereospecifically. The pure fluoro-chloro-platinates(IV) are separated by ion exchange chromatography on diethylaminoethyl-cellulose. The vibrational spectra o f the mixed ligand complexes are completely assigned according to point groups D4h, C4v, C3v and C2v. The Pt-Cl stretching vibrations of [PtF5Cl]2-, trans-[PtF4Cl2]2-, mer-[PtF3Cl3]2- and [PtFCl5]2- are split by the isotopes 35Cl and 37Cl, showing well resolved sharp Raman lines in the expected ratio of intensities.

Bindungsisomere Hexakis(selenocyanato(N)-selenocyanato(Se))-Osmate(III), [Os(NCSe)n(SeCN)6-n]3-, n = 0-3 / Bond Isomeric Hexakis(selenocyanato(N)-selenocyanato(Se)) Osmates(III), [Os(NCSe)n(SeCN)6-n]3-, n = 0-3

Six of ten possible linkage and geometric isomers of the formula [Os(NCSe)n(SeCN)6-n]3-, n = 0-3, have been obtained. The n = 0-2 complexes are prepared from the reactions of K2[OsX6] , X = Br, I, and of K2[OsO2(OH)4] in presence of ascorbic acid, with excess aqueous or methanolic KSeCN solutions at 20-40 °C. By heating the solid tetrabutylammonium salts, N-bonding of the ambident SeCN- is favoured, and the n = 3 species are formed. The complexes are separated by ion exchange chromatography and characterized by vibrational and electronic spectra. Characteristic group frequencies are: νOsSe: 183 - 216, νOsN: 224-246, νCSe(Se): 508-528, νCSe(N): 665-680, νCN: 2081-2122 cm-1.

Kristallstrukturen der iodierten closo-Hexaborate trans-(Ph4P)2[B6H4I2], mer-(Ph4P)2[B6H3I3] · 2 CH2Cl2, trans-(Ph4P)2[B6H2I4] · 2 CH3CN und (CH2Py2)[B6HI5]/Crystal Structures of the Iodized closo-Hexaborates trans-(Ph4P)2[B6H4I2], mer-(Ph4P)2[B6H3I3] · 2 CH2Cl2, trans-(Ph4P )2[B6H2I4] · 2 CH3CN and (CH2Py2)[B6HI5]

X-ray structure determinations have been performed on single crystals of trans-(Ph4P)2-[B6H4I2] (1) (triclinic, space group P1̄, a = 9.9680(12), b = 10.9690(11), c = 11.0470(14) Å,α = 88.167(9), β = 80.466(12), γ = 68.839(11)°, Z = 1), mer-(Ph4P)2[B6H3I3] · 2 CH2Cl2 (2)(triclinic, space group P1̄, a = 11.8694(11), b = 15.1699(13), c = 17.051(2) Å, α = 75.118(9), β = 71.953(10), γ = 69.331(8)°, Z = 2), trans-(Ph4P )2[B6H2I4] · 2 CH3CN (3) (monoclinic, space group P21/n, a = 14.9665(10), b = 7.6783(10), c = 23.385(3) Å, β = 95.78(9)°, Z = 2), and (CH2Py2)[B6HI5] (4) (orthorhombic, space group Pnma, a = 13.660(2), b = 11.8711(13), c = 13.839(2) Å, Z = 4). The B6 octahedra are compressed in the direction of the B-I bonds, resulting in shortened diagonal B ··· B distances with average values of the groups I-B ··· B-I = 2.37 and I-B ··· B-H = 2.43 Å as compared with H-B ··· B-H = 2.49 Å.

Darstellung und Schwingungsspektren von Chloro-Bromo-Platinaten(IV) einschließlich der Stereoisomeren / Preparation and Vibrational Spectra of Chloro-Bromo-Platinates(IV) Including Stereoisomers

The mixed chloro-bromo complexes [PtClnBr6-n]2-, n = 1-5, are separated by ion exchange chromatography on diethylaminoethylcellulose. The separation of corresponding stereoisomers for n = 2, 3, 4 is not possible. Due to the stronger trans-effect of Br compared with Cl, on treatment of [PtBrß]2- with Cl- in the presence of Br2 nearly pure cis-isomers, and by reaction of [PtClsBr]2- and cis-fPtC^Bro]2- with Br~/Br2 completely pure transisomers are formed. The stereoselectivity of the successive ligand exchange reactions is better than in corresponding series of Re, Os and Ir. The highly resolved vibrational spectra allow the distinction of the mixed ligand complexes as well as the estimation of purity of the isomers. All allowed stretching frequencies are observed and assigned according to point groups D4h, C4V, C3V and C2V. Especially in the ν(Pt-Br) region it is possible to distinguish bands arising either from symmetric Br-Pt-Br or asymmetric Cl-Pt-Br axes. The UV/VIS spectra exhibit systematic hypsochromic shifts on the successive exchange of Br-ligands by Cl. A critical discussion of the literature concerning chloro-bromo-platinates- (IV) shows the importance of effective separation processes for the isolation of pure mixed ligand complexes

Kristallstrukturen, Schwingungsspektren und Normalkoordinatenanalysen von trans-[PtX2(acac)2], X = CI, Br, I, SCN / Crystal Structures, Vibrational Spectra and Normal Coordinate Analyses of trans-[PtX2(acac)2], X = Cl, Br, I, SCN

The crystal structures of trans-[PtCl2(acac)2](monoclinic, space group P21/c, a - 7.616(5), b = 12.759(5), c = 7.892(5) Å, β = 118.459(5)°, Z = 2), trans-[PtBr2(acac)2] (triclinic, space group P1̅, a = 7.502(5), b = 7.665(5), c = 8.155(5) Å, α = 114~508(5), β = 94.537(5), γ = 117.669(5)°. Z = 1) and trans-[Pt(SCN)2(acac)2] (triclinic, space group P1̅ , a = 7.9095(10), b = 7.9393( 10), c = 7.9631 Å, a = 114.051 (10), β = 100.955(10), γ = 100.573(10)°, Z = 1) have been determined by single crystal X-ray diffraction analysis. The crystal structure of trans- [Ptl2(acac)2] is known from the literature. To enhance the spectroscopic resolution, the IR and Raman spectra of the four complexes have been measured at low temperature (10 K). Using the X-ray data, normal coordinate analyses based on a modified valence force field have been performed and the normal modes of vibration for the octahedral skeleton [PtX2O4] have been assigned. With a set of 19 or 23 force constants taking into account the inner-ligand vibrations a good agreement between observed and calculated frequencies has been achieved. The valence force constants are e.g.fd (PtCl) = 2.16, fd (PtBr) = 1.45, fd (PtI) = 1.01, fd (PtS) = 1.80 mdyn/Å, and fd (PtO) ranges from 1.89 to 1.91 mdyn/Å.

Darstellung, 11B-, 13C-, 1H-NMR-Spektren und Schwingungsspektren von 1,2-Xylylen-pentahydro-closo-hexaborat,cis-[B6H5(CH2)2C6H4]- , sowie Kristallstrukturen von cis-[P(C6H5)4][B6H5(CH2)2C6H4] und cis-[(n-C4H9)4N][B6H5(CH2)2C6H4] / Preparation, 11B, 13C, 1H NMR Spectra and Vibrational Spectra of 1,2-Xylylene-pentahydro-closo-hexaborate, cis-[B6H5(CH2)2C6H4]-, and the Crystal Structures of cis-[P(C6H5)4][B6H5(CH2)2C6H4] and cis-[(n-C4H9)4N ][B6H5(CH2)2C6H4]

By reaction of [B6H6]2- with ω,ω′-dibromo-o-xylene in acetonitrile the 1,2-xylylenepentahydro-closo-hexaborat, cis-[B6H5(CH2)2C6H4]- , is formed. The new ansa compound has been separated from excess [B6H6]2- and other reaction products by ion exchange chromatography on diethylaminoethyl cellulose. The crystal structures of cis-[P(C6H5)4][B6H5(CH2)2C6H4] (I) and as-[(n-C4H9)4N][B6H5(CH2)2C6H4] (II) have been determined by single crystal X-ray diffraction analysis: I is monoclinic, space group P 21/n with a = 13.715(5), b = 11.118(1) and c = 19.702(2) Å, β = 103.47(2)°; II is orthorhombic with a = 10.204(7), b = 13.352(4) and c = 20.824(8) Å. The 11B NMR spectrum confirms the structure with a hetero disubstituted octahedral B6 cage with local C2v symmetry. The 13C and 1H NMR spectra have been assigned in term of such a configuration. The IR and Raman spectra exhibit characteristic CH, BH, BC, B6 and arene vibrations.

Die Schwingungsfeinstruktur der elektronischen Absorptionsspektren von [OsO2(ox)2]2 -und [OsO2(mal)2]2-/ Vibrational Fine Structure on the Electronic Absorption Spectra of [OsO2(ox)2]2-and [OsO2(mal)2]2-

The complexes (TBA)2[OsO2(ox)2] and (TBA)2[OsO2(mal)2] have been prepared and characterized. The IR and Raman frequencies are assigned according to point group D2h. The electronic absorption spectra measured on thin films of the solid complex salts on silica discs at 10 K show well resolved vibrational fine structure. Two very weak bands (ε: 4-58) in the visible region are assigned to d-d transitions from the singlet ground state ag2 (dxy) to a triplet and singlet term of the equivalent π* orbitals b2g/b3g (dxz, dyz). The two more intense band systems (ε: 500-1500) in the UV region are attributed to CT transitions from b2u/b3u π orbitals of the oxo ligands to the lowest unoccupied orbitals b2g/b3g of the central ion. These electronic transitions couple with vs(Os = O) as indicated by the main progression of about 700 cm-1 . In comparison to the vibrational ground state this lowered frequency is caused by population of antibonding π levels. The loosening of the Os = O bonds in the excited state is demonstrated by high anharmonic constants (-2.5 to -10.5 cm-1) and the estimated bond lengthening of about 12 pm. Moreover the vibrational fine structure of the malonato complex shows many combination modes of vs(Os = O) with other symmetric fundamentals. Due to lower site symmetry in the solid state the CT transitions of the malonato compound are split into 2 components with a spacing of about 200 cm-1 .

Darstellung und Charakterisierung von cis-und trans-Dihalogeno-bis-acetylacetonato-osmaten(IV) / Preparation and Characterization of cis-and trans-Dihalogeno-bis-acetylacetonato-osmates(IV)

Cis-and trans-[OsX2(acac)2], X = Cl, Br, I, are prepared by heating of K2[OsX6] in a 1:1 mixture of acetylacetone: water. The pure stereoisomeres are separated by chromato-graphy on silica gel. The new complexes are characterized by UV-Vis, IR and Raman spectra.

Darstellung, Kristallstruktur, Schwingungsspektren und Normalkoordinatenanalyse von trans-[OsO2(N2H2C2O2)2]2- / Synthesis, Crystal Structure, Vibrational Spectra, and Normal Coordinate Analysis of trans-[OsO2(N2H2C202)2]2-

The treatment of K2[OsO2(OH)4] with oxamide in aqueous solution yields [OsO2(N2H2C2O2)2]2-. The crystal structure of trans-(Ph4P)2[ OsO2(N2H2C2O2)2]·CH2Cl2 (triclinic, space group P1̅, a = 10.447(1), b = 14.102(4), c = 16.962(2) Å, a = 90.037(1), β = 90.633(7), γ = 98.812(2)°, Z = 2) has been determined by single crystal X-ray diffraction analysis. The IR and Raman spectra were measured at room temperature. Based on the molecular parameters of the X-ray determination a normal coordinate analysis has been performed and the vibrations are assigned. The valence force constants are fd(Os=O) = 6.7, fd(Os-N) = 2.4, fd(C-N) = 4.9, fd(C=0) = 11.15 and fd(C-C) = 4.7 mdyn/Å.

Hexahydro-closo-hexaborate as a Ligand in Coordination Compounds: A Second Polymorph of [Au2(μ-bis-η3-B6H6)(PPh3)2]

The crystal structure of a second room-temperature polymorph of the complex [Au2(μ-bis-η3-B6H6)(PPh3)2] is presented and compared with the previously reported phase. The change of the solvent which is layered on a solution of [Au2(μ-bis-η3-B6H6)(PPh3)2] in CH2CI2 from petroleum ether to n-pentane leads to a second form with fundamental differences in the crystal structure. Instead of the octahedrally shaped crystals, space group Pa3̄, the crystals in the present determination are orthorhombic needles crystallizing in space group Pccn with a remarkable increased calculated density from 1.326 to 1.855 Mg/m3.

Darstellung,11B-NMR- und Schwingungsspektren der closo-Hexaborate [B6(SCN)6]2- und [B6(SeCN)6]2- / Preparation, 11 B-NMR and Vibrational Spectra of the closo-Hexaborates [B6(SCN)6]2- and [B6(SeCN)6]2-

On treatment of [N(C4H9)4][B6H7] with (SCN)2 or (SeCN)2 in dichloromethane in the presence of solid KOH the hexaborates [N(C4H9)4]2[B6(SCN)6] and [N(C4H9)4]2[B6(SeCN)6] are formed. The octahedral structure for the B6 cage is proven by 11B NMR spectroscopy. The chemical shifts in relation to BF3 · OEt2 of —9,7 (SCN) and —10,2 ppm (SeCN) show the influence of — I and +M effects of the substituents. The S(Se) coordination is deduced from vibrations within the substituents: νCN is observed at frequencies higher than 2100 cm-1 in the IR and Raman spectra, vcs at 662 and νcse at 556 cm-1 (intense IR bands).

Darstellung und spektroskopische Charakterisierung von Hexachloroosmat(V) / Preparation and Spectroscopical Characterisation of Hexachloroosmate(V)

(TEA)[OSCl6] is formed quantitatively by heating solid trans-(TEA)[OsX4(CO)2] (X = Br, I) in a stream of chlorine at 120 °C, and can be purified by recrystallisation from CH2Cl2 without decomposition. It is reduced immediately by acetone, methanol, Cl-, Br-, I- to give [OsCl6]2-. The standard potential [OsCl6]-/[OsCl6]2- in acetonitrile referred to the saturated mercury-mercurous sulphate electrode is 0.840 V. The IR and Ra bands of (TEA)[OsCl6], assigned according to point group Oh, are shifted to higher frequencies compared with (TEA)2[OsCl6]. The excitation at 488.0 nm gives a resonance Raman spectrum exhibiting 6 overtones of vi and combination tones up to 4ν1 + v5. The electronic absorption spectrum shows five spin-forbidden intraconfigurational transitions coupled with odd vibrational modes in the near infrared region. The spin-allowed 4A2g → 4T2g,4T1g-transitions are observed at 347 and 305 nm. The excited levels can be fitted with the parameters ⊿ = 28500 cm-1, B = 340 cm-1, ξ = 2500 cm-1 , allowing to calculate the nephelauxetic ratio β55 to 0.47. In the visible region extensive charge transfer transitions are observed. Based on the strong oxidizing character of Os(V) there is a bathochromic shift of corresponding bands of [OsCl6]- in relation to [OsCl6]2- of about 6600 cm-1 and to the isoelectronic [ReCl6]2- of about 13700 cm-1, respectively. From πt1u→dt2g the optical electronegativity is calculated to Xopt(Osv) = 2.49.

Schwingungsspektren und Normalkoordinatenanalyse der Tetrahalogeno-closo-1,2-diphosphahexaborane P2B4X4, X = Cl, Br / Vibrational Spectra and Normal Coordinate Analysis of the Tetrahalogeno-closo-1,2-diphosphahexaboranes P2B4X4, X = Cl, Br

High resolution vibrational spectra of the tetrahalogeno-closo-1,2-diphosphahexaboranes P2B4X4, X = Cl, Br have been measured at low temperatures (20 - 60 K). The boron-halogen stretching vibrations are observed below 370 cm-1 while the P-P valence vibrations are found at 414 (Cl) and 372 cm-1 (Br). Due to the presence of the boron isotopes 10B and 11B the P-P stretching vibrations and the cage modes in the region of 550 to 1200 cm-1 are split. Based on the crystallographic data of P2B4C14 normal coordinate analyses have been performed. Using a set of 16 force constants (e.g. fd(PP) = 1.35 (X = Cl) and 1.20 (Br), fd(BB) = 1.30 / 1.65 (Cl) and 1.45 /1.60 (Br), fd(BX) = 4.40 (Cl) and 3.53 (Br) mdyn / Å) a good agreement of observed and calculated frequencies has been achieved.

Darstellung, 11B-NMR- und Schwingungsspektren von μ-Distickstoff-bis(pentahydro-closo-hexaborat)(2-), [B6H5(NN)B6H5]2-sowie Kristallstruktur von [As(C6H5)4]2[B6H5(NN)B6H5] / Preparation, 11B NMR and Vibrational Spectra of μ-Dinitrogen-bis(pentahydro-closo-hexaborate)(2-), [B6H5(NN)B6H5]2 and the Crystal Structure of [As(C6H5)4]2[B6H5(NN)B6H5]

By reduction of [B6H5(NO2)]2- with aluminium powder in aqueous alkaline solution the orange μ-dinitrogen-bis(pentahydro-closo-hexaborate)(2-), [B6H5(NN)B6H5]2-, is formed, which can be precipitated with tetraphenylarsonium ions. The crystal structure of [As(C6H5)4]2[B6H5(NN)B6H5] has been determined by single crystal X-ray diffraction analy­sis; tetragonal, space group P4/n with a = 12.6610(12), c = 14.6790(11) Å. The B6 cages are slightly compressed (2%) in the direction of the connecting linear N2 bridge with bond lengths N-N of 1.129 and B-N of 1.421 Å. The 11B NMR spectrum exhibits signals at -27.0 (ipso-B), +1.26 (equatorial-B), +3.54 ppm (antipodal-B atoms). The NN stretching vibration is observed in the Raman spectra as a very strong line at 2065 cm-1.

Darstellung und Redoxverhalten aller bindungsisomeren Hexakis(thiocyanato(N)-thiocyanato(S))-osmate(III) und (IV), [Os(NCS)n(SCN)6-n]3-/2-, n = 0—6, einschließlich der Stereoisomeren / Preparation and Electrochemical Behaviour of All Bond-Isomeric Hexakis(thiocyanato(N)-thiocyanato(S))osmates(III) and (IV), [Os(NCS)n(SCN)6-n]3-/2-, n = 0—6, Including Stereoisomers

The first two complete series of all 10 possible linkage and geometric isomers of the general formula [Os(NCS)n(SCN)6-n]3-/2- have been obtained. The Os(III) complexes, some of which have been previously known, are prepared from the reactions of K2[OsX6], X = Cl. Br. I, and K2[OsO2(OH)4] with excess aqueous or methanolic KSCN solution and subsequent chromato­graphic separation on DEAE cellulose. Oxidation with Ce(IV) in acetone or methanol yields the corresponding Os(IV) compounds without changes in the ligand sphere except for n = 0, but pure salts of [Os(SCN)6]2“ are isolated by repeated recrystallization. S-bonding is less favoured in Os(IV) than in Os(III), proving that Os(IV) is the harder Lewis acid. Cyclic voltammograms of all isomers show two waves, a mainly irreversible Os(II)/Os(III) couple and a reversible Os(III)/Os(IV) couple. Characteristic shifts of the half-wave potentials of both electron transfer reactions within the series give strong evidence of π-back donation to -NCS.

Reaktionen und Strukturen von [(C2H5)4N][OsCl6] und [(n-C4H9)4N]2[Os2Cl10] / Reactions and Structures of [(C2H5)4N][OsCl6] and [(n-C4H9)4N]2[Os2Cl10]

On heating of [(C2H5)4N][OsCl6] for a short time at 240 °C , Cl2 is lost and [(C2H5)4N]2[Os2Cl10] is formed quantitatively. Both complexes are connected by a temperature dependent redox equilibrium so that by treatment at 120 °C with Cl2 gas the hexachloroosmate(V) is recovered from the decachlorodiosmate(IV). The crystal structures of salts of both an ions were determined from single crystal X -ray diffraction analyses. [(C2H5)4N][OsCl6] is monoclinic, space group P2 1 with a = 7 .020 (1), b = 10 .163 (2), c = 11.609 (2) Å , β = 103.91(1)° (at - 133 °C ). The strongly pseudocentrosymmetric structure shows a reversible phase transition at ca. 85 °C. The Os -Cl bond length (mean value 2.303 Å) in the regular [OsCl6]-octahedra is significantly smaller than in [OsCl6]2− , in accordance with vibrational spectra. [(n -C4H9)4N]2 [Os2Cl10] crystallizes in the orthorhombic space group Pbca with a = 15 .496 (2), b = 15 .965 (3), c = 19 .431(3) Å and contains centrosymmetric [Os2Cl10]2− ions with approximate D2h symmetry. Within the edge-sharing [OsCl6] octahedra the mean terminal and bridging Os -Cl bond lengths are 2.307 and 2.411 Å , respectively.

Nachweis der isotopomeren closo-Hydrohexaborate 11Bn 10B6-nH6 2- , n = 0—6, durch Tieftemperatur-Raman-Spektroskopie / Detection of the Isotopomeric closo-Hydrohexaborates 11Bn 10B6-nH6 2- , n = 0—6, by Low Temperature Raman Spectroscopy

Abstract The low temperature Raman spectra (10 K) of Cs2B6H6 and its 11B and 10B enriched derivatives prepared for the first time show well resolved signals o f the B6-cage vibrations υ1 (A1g), υ3(Eg) and υ9(T2g) for all isotopomers 11B10B6-nH6 2 -, n = 0-6. The intensities o f the sharp peaks correlate exactly with the statistical abundance ratio. W hereas the frequency decreases by nearly equidistant steps of 7 cm-1 with increasing n values, the geometric isomers for n = 2, 3 and 4 are separated by only about 2 cm-1. The band assignments are verified by Teller-Redlich calculations.

Darstellung und spektroskopische Charakterisierung von Methylnitro-closo-hexaboraten sowie Kristallstrukturen von cis-(Ph4As)2[B6H4(CH3)(NO2)],fac-(Ph4As)2[B6H3(CH3)(NO2)2] · CH3CN und mer-(Ph4P)2[B6H3(CH3)(NO2)C2] / Synthesis and Spectroscopic Characterization of Methylnitro-closo-hexaborates and Crystal Structures of cis -(Ph4As)2[B6H4(CH3)(NO2)],fac-(Ph4As)2[B6H3(CH3)(NO2)2] · CH3CN and mer-(Ph4P)2[B6H3(CH3)(NO2)C2]

By electrochemical oxidation of (n-Bu4N)[B6H6(CH3)] in the presence of nitrite ions and of the base DBU in dichloromethane solution cis- and trans-[B6H4(CH3)(NO2)]2- , fac- [B6H3(CH3)(NO2)2]2- and mer-[B6H3(CH3)(NO2)c 2]2- are formed. X-ray diffraction analyses have been performed on single crystals of cis-(Ph4As)2[B6H4(CH3O)(NO2)] (1) (monoclinic, space group P21/a, a = 20.063(2), b = 10.858(1), c =21.384(2) Å, β = 105.818(9)°, Z = 4), fac-(Ph4As)2[B6H3(CH3)(NO2)2] ·CH3CN (2) (triclinic, space group P1̄, a = 10.333(3), b = 10.695(3), c = 22.833(6) Å, α = 93.91(3), β = 96.79(3), γ = 104.56(2)°, Z = 2), and mer-(Ph4P)2[B6H3(CH3)(NO2)c 2] (3) (triclinic, space group P1̄, a - 10.100(1), b = 10.402(3), c = 22.923(3) Å, α = 96.328(18), β = 89.928(12), γ = 107.963(16)°, Z = 2). The 11B NMR spectra and the vibrational spectra of the methylnitro compounds are discussed and compared with those of the monomethyl- and mononitro-closo-hexaborates.

Darstellung, 11B-, 13C-NMR- und Schwingungsspektren von Cs2[B6H5(p-C6H4(NO2))] und Cs2[B6H5(C6H3-l-(CH3)-5-(NO2))] sowie Kristallstruktur von (CH2Py2)[B6Cl5(p-C6H4(NO2))]·CH3CN / Preparation, 11B , 13C-NMR and Vibrational Spectra of Cs2[B6H5(p-C6H4(NO2))], Cs2[B6H5 (C6H3-1 -(CH3 )-5-(NO2))] and Crystal Structure of (CH2Py2)[B6Cl5(p-C6H4(NO2))]·CH3CN

The first aryl derivatives of c/oso-hexahydrohexaborate are formed by reaction of [B6H6]2- with 1-bromo-4-nitrobenzene and 2-bromo-5-nitrotoluene in acetonitrile at 80 °C. Cs2[B6H5- (1,4-C6H4(NO2))] and Cs2[B6H5(C6H3-1-(CH3)-5-(NO2))] can be isolated by ion exchange chromatography on diethylaminoethyl (DEAE) cellulose. Further treatment with /V-chlorosuccinimide yields the perhalogenated derivative (CH2Py2)[B6Cl5(1,4-Ph(NO2))]CH3CN which has been characterized by X-ray diffraction analysis (orthorhombic, space group P2( 2,2t, a = 9.810(4), b - 14.412(3), c - 18.586(9) A, Z = 4). The 11B NMR spectra of all compounds are consistent with a monosubstituted B6-cluster. The IR and Raman spectra exhibit characteristic BB, BH, CH, CC and NO vibrations, respectively.

Darstellung und spektroskopische Charakterisierung von Tetrakis (chloro -iodo ) oxalato -osmaten (IV )/Preparation and Spectroscopical Characterisation of Tetrakis(chloro-iodo)oxalato-osmates(IV)

On treatment of [OsI4ox]2- with Cl- the mixed complexes [OsClnI4-nox]2-, n = 1, 2, 3, are formed. The isolation and complete separation of the differently coloured geometric isomers is achieved by ion exchange chromatography on diethylaminoethyl cellulose. The IR and Ra spectra are assigned according to point groups C2v, Cs, C1. The mutual influence of ligands, especially by the high trans effect of I, is indicated by shifts of the distinct vibrational and electronic bands. The observed splittings of I→Os transitions are attributed to the different groupings I-Os-I, I-Os-Cl, and I-Os-O, important for the distinction of stereoisomers. The CT-bands as well as the d-d-transitions show batho-chromic shifts with increasing number of I-ligands. Up to five spin-orbit components in the NIR region are well resolved. The assignment is improved by the electronic Ra spectra. The fine structure of some d-d-bands originates from coupling with symmetric vibrational modes.

Darstellung und Schwingungsspektren von Chloro-Bromo-Ruthenaten(IV) einschließlich der Stereoisomeren / Preparation and Vibrational Spectra of Chloro-Bromo-Ruthenates(IV) Including Stereoisomers

The mixed chloro-bromo complexes [RuClnBr6-n]2-, n = 1-5, have been separated for the first time by ion exchange chromatography on diethylaminoethylcellulose. Due to the stronger trans-effect of Br compared with Cl, on treatment of [RuBr6]2- with Cl- in the presence of Br2 nearly pure cis/fac-isomers,and by reaction of [RuCl6]2- withBr-/Br2 nearly purer tranS/mer-isomersforn = 2,3,4 are formed. The vibrational spectra of the mixed ligand complexes are completely assigned according to point groups D4h, C4v, C3v and C2v, respectively. The bands are observed in the characteristic regions: ν(RuCl): 340-270 > ν(RuBr): 245-190 > δ(ClRuCl) ≥ δ(ClRubr) ≥ δ(BrRuBr): 125-90 > νʟ: < 100 cm-1. The lower stability of the hexahalogeno complexes of Ru(IV), 4d, compared with the homologous complexes of Os(IV), 5d, is confirmed by a decrease of the force field constants by approximately 15%.

Darstellung, schwingungsspektren und Normalkoordinatenanalyse der Bromo-Iodo-Rhenate(IV), [ReRrnI6-n]2-, n = 0-6 / Preparation, vibrational spectra, and normal coordinate analysis of bromo-iodo-rhenates(iv), [ReRrnI6-n]2-, n = 0-6

The IR and Raman spectra of the ten bromo-iodo-rhenates(IV) [ReBrnI6-n]2-, n = 0 -6 , including the geometrical isomers for n - 2,3,4, have been recorded at 80 K. The vibrational spectra are completely assigned according to point groups Oh, D4h, C4v, C3v, and C2v, as supported by normal coordinate analyses based on a general valence force field. Due to the different mms-influences Br < I in asymmetric axes Br•-Re-I', the Re-I' bonds are strengthened and the Re-Br• bonds are weakened, as indicated by valence force constants, for Re-I' on average 8,5% higher and for Os-Br• 8,3% lower, as compared with the values calculated for symmetric I-Re-I and Br-Re-Br axes, respectively

Darstellung, 11B-, 13C -, 1H-NMR- und Schwingungsspektren von 2,2' -Bipyridylundecahydro-closo-dodecaborat(1-) sowie Kristallstruktur von (Ph4As)[(2,2′-C10H8N2)B12Hn ]·CH3CN / Synthesis, 11B, 13C, 1H NMR and Vibrational Spectra of 2 ,2'-Bipyridyl-undecahydro-closo-dodecaborate(1-) and Crystal Structure of (Ph4As)[(2 ,2'-C10H8N2)B12H11]-CH3CN

By reaction of (n-Bu4N)2[B12H12] with 2,2′-bipyridine at 190 °C the 2,2′-bipyridyl-undecahydro- closo-dodecaborate anion [(2,2′-C10H8N2)B12H11]− is formed which can be seperated from excess [B12H12]2− by ion exchange chromatography on diethylaminoethyl (DEAE) cellulose. The X-ray structure determination of (Ph4As)[(2, 2′-C10H8N2)B12H11] (monoclinic, space group P21/c with a = 13.3190(9), b = 10.1532(14), c = 28.788(3′) Å, β = 96.761(7)°, Z = 4) reveals that the bipyridyl substituent is bonded via one nitrogen atom. The 11B NMR spectrum exhibits a 1:5:5:1 pattern with ipso-B1 at -0.3, B2-B6 at -14.5, B7-B11 at -15.3 and antipodal-B12 at -15.9 ppm. The 13C and 1H NMR spectra show the characteristic patterns of the bipyridyl group in the range of 124.5 to 158.6 (13C) and 7.4 to 9.6 ppm (1H) respectively. The IR and Raman spectra exhibit characteristic BH stretching vibrations between 2445 and 2568 cm-1 and the stretching of the CC and CN bonds in the range of 1427 to 1619 cm-1 .

Schwingungsspektren und Normalkoordinatenanalyse der Acetatohalogenodimetallate M2(O2CCH3)4X2, M = Re, Tc; X = CI, Br/Vibrational Spectra and Normal Coordinate Analysis of Acetatohalogenodimetalates M2(O2CCH3)4X2, M = Re, Tc; X = Cl, Br

The orange-red Tc2(O2CCH3)4Br2 has been prepared for the first time by reaction of [Tc2Br8]2- with glacial acetic acid and acetic anhydride. The IR and Raman spectra have been recorded at 80 K and are compared with those of the analogous compounds Tc2(O2CCH3)4Cl2, Re2(O2CCH3)4Cl2 and Re2(O2CCH3)4Br2. The assignment according to the point group D4h is supported by normal coordinate analysis based on a general valence force field. The quadruple M - M bond is stabilized by the bridging acetato and destabilized by the axial halogeno ligands. The valence force constants fd(MM) are determined to 3,96-4,08 mdyn/Å. The interaction constants fdd(MM/MX), fdd(MM/MO) and fdα (MM/MMO) are about three times higher for the technetates as compared with the rhenates. The stronger interaction between oppo­site bonds in the equatorial ligand sphere is revealed by the stretching interaction constants fdd', which are about two times higher than fdd for M - O bonds at right angles. The strong coupling of the ring co-ordinates implies extensive mixing of the M - O valence and deformation modes. The electronic spectra of Tc2(O2CCH3)4X2, agree with those of the corresponding Re compounds.

Darstellung und Schwingungsspektren von Fluoro-Chloro-Iridaten(IV) einschließlich der Stereoisomeren / Preparation and Vibrational Spectra of Fluoro-Chloro-Iridates(IV) Including Stereoisomers

The reaction of [IrCl6]2- with BrF3 generates the mixed complexes [IrFnCl6-n]2-, n = 1-5, of which the species with n = 2, 3, 4 are ds-configurated. Due to the stronger trans-effect of Cl as compared to F on treatment of [IrF5Cl]2- and cis-[IrF4Cl2]2- with SOCl2 the trans-isomers are formed stereospecifically. The pure fluoro-chloro-iridates(IV) are separated by ion exchange chromatography on diethylaminoethyl-cellulose. The vibrational spectra of the mixed ligand complexes are completely assigned according to point groups D4h, C4v, C3v, and C2v. The IrCl stretching vibration of [IrF5Cl]2- is split by the isotopes 35C1 and 37Cl, showing two well resolved sharp Raman lines at 361 and 355 cm-1.

Kristallstrukturen von [P(C6H5)4]2[B6Cl6](CH3CN)2 und [P(C6H5)4]2[B6Br6](CH3CN)2 sowie Schwingungsspektren und Normalkoordinatenanalyse der isotopomeren closo-Hexahalogenohexaborate [11Bn 10B6-nX6]2-, Χ = Cl, Br; n = 0-6 / Crystal Structures of [P(C6H5)4]2[B6Cl6](CH3CN)2 and [P(C6H5)4]2[B6Br6](CH3CN)2, Vibrational Spectra and Normal Coordinate Analysis of Isotopomeric closo-Hexahalogenohexaborates [11Bn 10B6-nX6]2-, X = Cl, Br; n = 0-6

The crystal structures of (TPP)2[B6Cl6](CH3CN)2 and (TPP)2[B6Br6](CH3CN)2 were determined from single crystal X-ray diffraction analyses at 147 K. They are triclinic, space group P1̅, and contain nearly regular octahedral anions with bond lengths d(B-B) 1.716, d(B-Cl) 1.818 for [B6Cl6]2- and d̅(B-B) 1.684, d̅(B-Br) 1.993 Å for [B6Br6]2-. Using these molecular data, normal coordinate analyses for the ten isotopomers [11Bn 10B6-nX6]2-, n = 0-6, X = Cl, Br, including the pairs of geometric isomers for n = 2, 3, 4 have been performed, based on a general valence force field. With a set of 8 force constants for Cs2[B6Br6] (e.g. fd(BB) = 1.39, fd(BBr) = 3.18 mdyn/Å) and 10 for Cs2[B6Cl16] (e. g. fd(BB) = 1.30, fd(BCl) = 4.01 mdyn/Å) the calculated frequencies are in good agreement with observed IR (10 K) and Raman bands (80 K) in natural abundance as well as for 11B- and 10B-enriched derivatives. For the series [B6X6]2-, X = Cl, Br, I the correlation of decreasing bond lengths d(B-B) and increasing force constants fd(BB) along with vibrational coupling between the B6 cage and the substituent sphere is discussed.

Darstellung und spektroskopische Charakterisierung von (η3-Hexahydro-closo-hexaborato)phenylquecksilber(1-) [Hg(η3-B6H6)Ph] sowie Kristallstruktur von [PPh4][Hg(η3-B6H6)Ph] / Preparation and Spectroscopic Characterization of (η3-Hexahydro-closo-hexaborato)phenylmercury(1 -) [Hg(η3-B6H6)Ph]- and Crystal Structure of [PPh4][Hg(η3-B6H6)Ph]

By reaction of [B6H7]- with PhHg(CH3COO) in dichloromethane [Hg(η3-B6H6)Ph]- is formed. The crystal structure of [PPh4][Hg(η3-B6H6)Ph] has been determined by single crystal X-ray diffraction analysis; monoclinic space group P 21/c with a = 9.567(5) Å, b = 22.213(5) Å, c = 14.296(5) Å, β = 94.484(5)°. The 11B NMR spectrum exhibits a doublet at -9.9 ppm shifted to lower field as compared with [B6H7]- and the 199Hg NMR spectrum a singlet at -74.5 ppm. In the IR and Raman spectra characteristic B-H vibrations are observed

Darstellung, Schwingungsspektren und Normalkoordinatenanalyse von (n-Bu4N)2[Pt(SCN)n(ox)], n = 2, 4, sowie Kristallstruktur von [(C5H5N)2CH2][Pt(SCN)4(ox)] / Synthesis, Vibrational Spectra and Normal Coordinate Analysis of (n-Bu4N)2[Pt(SCN)n(ox)], n = 2, 4, and Crystal Structure of [(C5H5N)2CH2][Pt(SCN)4(ox)]

On exposure of trans-(n-Bu4N)2[Pt(SCN)2(ox)2] to photochemical reduction (n-Bu4N)2- [Pt(SCN)2(ox)] (1) is formed. Further treatment with (SCN)2 yields (n-Bu4N)2- [Pt(SCN)4(ox)] (2). The X-ray structure determination on a single crystal was performed of [(C5H5N)2CH2][Pt(SCN)4 (ox)] (triclinic, space group P1̅, a = 9.823(1), b = 14.850(1), c = 15.799(1) Å , α= 74.304(9), β= 86.268(9), γ= 87.455(9)°, Z = 4). Based on the molecular parameters of the X-ray determination the IR and Raman spectra have been assigned by normal coordinate analysis. The valence force constants of the symmetric axis S-Pt-S and of the asymmetrically coordinated S'-Pt-O* axes are fd(PtS) = 1.71, fd(PtS') = 1.92 (1), fd(PtS') = 2.02 (2) and fd(PtO•) = 2.45 (1) and 2.24 (2) mdyn/Å. Taking into account increments of the trans influence a good agreement between observed and calculated frequencies is achieved. The NMR shifts are δ(195Pt) = 1967.7 (1) and 2930.8 ppm (2)

Darstellung, 11B-, 13C-, 1H-NMR- und Schwingungsspektren von μ-Methylen-bis-hexahydro-closo-hexaborat, [B6H6(CH2)B6H6]2-, und Kristallstruktur von [As(C6H5)4]2[B6H6(CH2)B6H6]· ½(CH3)2CO / Preparation, 11B- , 13C-, 1H NMR and Vibrational Spectra of μ-Methylene-bis-hexahydro-doso-hexaborate, [B6H6(CH2)B6H6]2- and Crystal Structure of [As(C6H5)4]2[B6H6(CH2)B6H6]· ½(CH3)2CO

By reaction of [B6H6]2- with dibromomethane in acetonitrile μ-Methylene-bis-hexahydro-closo-hexaborate, [B6H6(CH2)B6H6]2-, is formed which can be separated from excess [B6H6]2- by ion exchange chromatography on diethylaminoethyl cellulose. The crystal structure of [As(C6H5)4]2[B6H6(C H2)B6H6] · (CH3)2CO has been determined by single crystal X-ray analysis: triclinic, space group P1 with a = 10.779(2), b = 10.8003(12) and c = 23.077(3) Å, a = 99.147(10), β = 91.569(13) and y = 91.288(11)°. The 11B NMR spectrum reveals the features of a monosubstituted octahedral B6 cage. The 13C NMR spectrum exhibits a multiplet at -5.44 ppm. In the 1H NM R spectrum a singlet of the methylene protons at 0.23 ppm and two singlets at 1.97 and -4.52 ppm of the BH fragments are observed. The IR and Raman spectra exhibit strong CH stretching bands between 2873 and 2762 cm-1, BH stretching bands between 2443 and 2403 cm-1, and a BC stretching vibration at 1138 cm-1 in the Raman spectrum.