Synthesis, structure and properties of ferrocene functionalized porphyrins

A series of free-base and metallated mixed ferrocenamido- and pivalamidophenylporphy-rins have been prepared from the α,α′,α″,α‴ isomer of 5,10,15,20-tetra(o-aminophenyl)porphyrin. The X-ray crystal structure of the iron(III) α,α′,α″,α‴-5,10,15,20-tetrakis(o-ferrocenamidophenyl)-porphyrin bromide has been determined and compared with related structures of cobalt(III) α,α′,α″,α‴-5,10,15,20-tetrakis(o-pivalamidophenyl)porphyrin bromide pyridine and the free base α,α′,α″,α‴-5,10,15,20-tetrakis(o-pivalamidophenyl)porphyrin. In both metalloporphyrins the coordinated axial bromides are contained in the cavity formed by the appended pickets with all the amide N - H bonds directed toward the anion.

Bis(N,N-diethyldithiocarbamato)(1,10-phenanthroline)cobalt(III) tetrafluoridoborate

The cationic complex in the structure of the title compound, [Co(Et₂NCS₂)₂(C₁₂H₈N₂)]BF₄, has a Co^III atom with a distorted octa­hedral coordination formed by four S atoms of two diethyl­dithio­carbamate and two N atoms of 1,10-phenanthroline ligands. The crystal structure features head-to-tail stacking of the phenanthroline ligands. The tetra­fluorido­borate anions are positioned in the channels between the cation stacks running along the a axis, and form weak C—H⋯F interactions.

Bis(1-ferrocenylbutane-1,3-dionato-kappa2O,O')copper(II) and bis(1,3-diferrocenylpropane-1,3-dionato-kappa2O,O')copper(II)

The title compounds, [CuFe2(C5H5)2(C9H8O2)2], (I), and [CuFe4(C5H5)4(C13H9O2)2], (II), are four-coordinate square-planar copper(II) complexes with two bidentate 1-ferrocenylbutane-1,3-dionate or 1,3-diferrocenylpropane-1,3-dionate ligands, respectively. The copper ion in (I) lies on an inversion centre, with one-half of the molecule in the asymmetric unit, while in (II), there are two independent half molecules in the asymmetric unit, with the copper ions also situated on inversion centres. The ferrocene substituents in (I) are in an anti arrangement. The molecules assemble in the crystal structure in layers with ferrocene groups at the surface. The pairs of ferrocene substituents on each ligand in complex (II) are syn and these adopt an anti arrangement with respect to the pair on the other diketonate ligand. As found in (I), complexes assemble in a layered structure with ferrocene-coated surfaces.

Molecular structure of the solvated proton in isolated salts. Short, strong, low barrier (SSLB) H-bonds

Large, inert, weakly basic carborane anions of the icosahedral type CHB(11)R(5)X(6)(-) (R = H, Me; X = Cl, Br) allow ready isolation and structural characterization of discrete salts of the solvated proton, [H(solvent)(x)][CHB(11)R(5)X(6)], (solvent = common O-atom donor). These oxonium ion Brønsted acids are convenient reagents for the tuned delivery of protons to organic solvents with a specified number of donor solvent molecules and with acidities leveled to those of the chosen donor solvent. They have greater thermal stability than the popular [H(OEt(2))(2)][BAr(F)] acids based on fluorinated tetraphenylborate counterions because carborane anions can sustain much higher levels of acidity. When organic O-atom donors such as diethyl ether, tetrahydrofuran, benzophenone, and nitrobenzene are involved, the coordination number of the proton (x) in [H(solvent)(x)()](+) is two. A mixed species involving the [H(H(2)O)(diethyl ether)](+) ion has also been isolated. These solid-state structures provide expectations for the predominant molecular structures of solvated protons in solution and take into account that water is an inevitable impurity in organic solvents. The O.O distances are all short, lying within the range from 2.35 to 2.48 A. They are consistent with strong, linear O.H.O hydrogen bonding. Density functional theory calculations indicate that all H(solvent)(2)(+) cations have low barriers to movement of the proton within an interval along the O.H.O trajectory, i.e., they are examples of so-called SSLB H-bonds (short, strong, low-barrier). Unusually broadened IR bands, diagnostic of SSLB H-bonds, are observed in these H(solvent)(2)(+) cations.

Nickel(II) Compounds of a Tetraazacyclopentadecene; the Structure of (1RS,3SR,8SR,12SR,13RS)-(3,5,7,7,13,15,15-Heptamethyl-1,4,8,12-tetraazacyclopentadec-4-ene-N1,N4,N8,N12)-nickel(II) Perchlorate

One imine function of (3,5,7,7,13,15,15-heptamethyl-1,4,8,12-tetraazacyclopentadeca-4,12-diene)nickel(II) is reduced by NaBH4 to form the mono-imine-triamine cation, which forms an orange, S = 1, perchlorate salt and a blue-violet, S = 3, dithiocyanato compound. The structure of (1RS,3SR,8SR,12SR,13RS)-(3,5,7,7,13,15,15-heptamethyl-1,4,8,12-tetraazacyclopentadeca-4-ene-N1,N4,N8,N12) nickel(II) perchlorate is reported. The unit cell contains two independent but closely similar cations, with tetrahedrally-twisted square-planar coordination {mean deviations from N4 planes; ± 0.23 Å, with Ni 0.05 Å from the plane; mean distances; Ni–Namine 1.925(5), Ni–Nimine 1.907(9) Å [C18H38Cl2N4NiO8, triclinic, space group P1, a 8.6793(2), b 8.6808(2), c 16.8278(4) Å, α 90.080(1), β 90.004(1), γ 93.348(1)°, Z 2, R 1 0.063 for 9906 reflections with I>2σ (I)]}.

Synthesis and Structural Analysis of a Helical Coordination Polymer Formed by the Self-Assembly of a 2,2'-Bipyridine-Based exo-Ditopic Macrocyclic Ligand and Silver Cations

The overall topology of coordination polymers can be controlled by means of the coordination preferences of the metal center and the structure of the bridging ligand. This is demonstrated here by the synthesis of a single-stranded helical coordination polymer by the self-assembly of the exo-ditopic ligand 1 and silver ions.

Oxidative Decarboxylation of Podocarpic Acid Derivatives

The radical decarboxylation–sulfoxide cycloelimination of 2′-pyridylthio esters formed from a series of podocarpic acid derivatives gives Δ4(18) -alkenes in high yield. An exception is the 13-nitro acid (2) which affords a thiohydroxamic ester (28), the relative stability of which is attributed to inhibition of the radical chain reaction by the nitro group. The stereochemistry of the pyridyl sulfide (18) has been confirmed by X-ray crystallography.