Spectral studies on metal-ligand bonding of novel rhodanine azodye sulphadrugs

Synthesis and spectroscopical study of rhodanine derivative using DFT approaches

The optimized molecular structure, vibrational frequencies, corresponding vibrational assignments of (E)-5-benzylidene-2-thioxothiazolidine-4-one (E5BTTO) have been investigated experimentally and theoretically based on Density Functional Theory (DFT) approach. The FT-Raman and FT-IR spectra of E5BTTO were recorded in solid phase. Theoretical calculations were performed at the DFT level using the Gaussian 03 program. The experimental bands were assigned and characterized on the basis of the scaled theoretical wavenumber by their Total Energy Distribution (TED). The results of the calculation were applied to simulate infrared and raman spectra of the title compound which showed good agreement with the observed spectra. The calculated HOMO and LUMO energies show that charge transfer occur within the molecule. Stability arising from hyperconjugative interactions leading to its NLO activity and charge delocalization were analyzed using Natural Bond Orbital (NBO) analysis.

Polymer complexes. LX. Supramolecular coordination and structures of N(4-(acrylamido)-2-hydroxybenzoic acid) polymer complexes

A number of novel polymer complexes of various anions of copper(II), cobalt(II), nickel(II) and uranyl(II) with N(4-(acrylamido)-2-hydroxy benzoic acid) (ABH) have been synthesized and characterized by elemental analysis, IR, 1H NMR, magnetic susceptibility measurements, electronic spin resonance, vibrational spectra and thermal analysis. The molecular structures of the ligand are optimized theoretically and the quantum chemical parameters are calculated. Tentative structures for the polymeric metal complexes due to their potential application are also suggested. The IR data exhibit the coordination of ONO2/OAc/SO4 with the metal ions in the polymeric metal complex. Vibrational spectra indicate coordination of carboxylate oxygen and phenolic OH of the ligand giving a MO4 square planar chromophore. Ligand field ESR spectra support square planar geometry around Cu(II). The thermal decomposition of the polymer complexes were discussed in relation to structure, and the thermodynamic parameters of the decomposition stages were evaluated applying Coast-Redfern and Horowitz-Metzger methods.

Supramolecular spectral studies on metal-ligand bonding of novel quinoline azodyes

A series of novel bidentate azodye quinoline ligands were synthesized with various p-aromatic amines like p-(OCH3, CH3, H, Cl and NO2). All ligands and their complexes have been characterized on the basis of elemental analysis, IR, (1)H and (13)C NMR data and spectroscopic studies. IR and (1)H NMR studies reveal that the ligands (HLn) exists in the tautomeric azo/hydrazo form in both states with intramolecular hydrogen bonding. The ligands obtained contain NN and phenolic functional groups in different positions with respect to the quinoline group. IR spectra show that the azo compounds (HLn) act as monobasic bidentate ligand by coordinating via the azodye (NN) and oxygen atom of the phenolic group. The ESR (g|| and g ) and bonding α(2) parameters of the copper ion were greatly affected by substituting several groups position of ring of quinoline and p-aromatic ring. The ESR spectra of copper complexes in powder form show a broad signal with values in order g|| >g > ge > 2.0023. The value of covalency factor β and orbital reduction factor K accounts for the covalent nature of the complexes. All complexes possessed an octahedral and square planar geometry. The thermal properties of the complexes were investigated using TGA and DSC. It is found that the change of substituent affects the thermal properties of complexes.

Synthesis and characterization of Cu(II), Co(II) and Ni(II) complexes of a number of sulfadrug azodyes and their application for wastewater treatment

The azodye ligand (HL(1)) was synthesized from the coupling of sulfaguanidine diazonium salt with 2,4-dihydroxy-benzaldehyde while the two ligands, HL(2) and HL(3), were prepared by the coupling of sulfadiazine diazonium salt with salicylaldehyde (HL(2)) and 2,4-dihydroxy-benzaldehyde (HL(3)). The prepared ligands were characterized by elemental analysis, IR, (1)H NMR and mass spectra. Cu(II), Co(II) and Ni(II) complexes of the prepared ligands have been synthesized and characterized by various spectroscopic techniques like IR, UV-Visible as well as magnetic and thermal (TG and DTA) measurements. It was found that all the ligands behave as a monobasic bidentate which coordinated to the metal center through the azo nitrogen and α-hydroxy oxygen atoms in the case of HL(1) and HL(3). HL(2) coordinated to the metal center through sulfonamide oxygen and pyrimidine nitrogen. The applications of the prepared complexes in the oxidative degradation of indigo carmine dye exhibited good catalytic activity in the presence of H2O2 as an oxidant. The reactions followed first-order kinetics and the rate constants were determined. The degradation reaction involved the catalytic action of the azo-dye complexes toward H2O2 decomposition, which can lead to the generation of HO radicals as a highly efficient oxidant attacking the target dye. The detailed kinetic studies and the mechanism of these catalytic reactions are under consideration in our group.

Polymer complexes. LVIII. Structures of supramolecular assemblies of vanadium with chelating groups

Oxovanadium(IV) polymer complexes of formulation {[(VO)L](2)}(n) (1) and [(VO)LB](n) (2-4), where H(2)L is tridentate and dianionic ligand (allylazorhodanine) and B is planar heterocyclic and aliphatic base have been prepared and characterized by elemental analyses, IR, (1)H NMR, electronic spin resonance spectra, magnetic susceptibility measurements, molar conductance and thermal studies. The molecular structure shows the presence of a vanadyl group in six-coordinate VNO(3)/VN(3)O(3) coordination geometry. The N,N-donor heterocyclic and aliphatic bas displays a chelating mode of binding with an N-donor site trans to the vanadyl oxo-group. In all polymeric complexes (1-4) the ligand coordinates through oxygen of phenolic/enolic and azodye nitrogen. The molar conductivity data show them to be non-electrolytes. All the polymer complexes are ESR active due to the presence of an unpaired electron. The calculated bonding parameters indicate that in-plane σ bonding is more covalent than in-plane π bonding. From the electronic, magnetic and ESR spectral data suggest that all the oxovanadium(IV) polymer complexes have distorted octahedral geometry. The thermal decomposition process of the polymeric complexes involves three decomposition steps.

Polymer complexes: XLXII-interplay of coordination π-π stacking and hydrogen bonding in supramolecular assembly of [sulpha drug derivatives-N,S:N,O] complexes

A novel series of nickel(II) polymer complexes of 5-sulphadiazineazo-3-phenylamino-2-thio-4-thiazolidinone (HL₁), 5-sulphamethazine-3-phenylamino-2-thioxo-4-thiazolidinone (HL₂), 5-sulphamethoxazole-3-phenylamino-2-thioxo-4-thiazolidinone (HL₃), 5-sulphacetamide-3-phenyl-2-thioxo-4-thiazolidinone (HL₄) and 5-sulphaguanidine-3-phenylamino-2-thioxo-4-thiazolidinone (HL₅) were prepared and characterized. IR spectra show that HL(n) (n=1-5) is coordinated to the metal ion in a neutral tetradentate manner with NSNO donor sites of NH (hydrazone's), NH (3-phenylamine), carbonyl group and Ph-NH. The title [Ni₃(HL(n))₂(μ-OAc)₂(OAc)₄](n) consists of three Ni(II) atoms linked by interchain π-π interaction are observed between aromatic rings of two ligands (HL(n)) which are further doubly bridged two adjacent nickel atoms by acetate group. The geometrical structures of these complexes are found to be octahedral. The nature of bonding and the stereochemistry of the complexes have been deduced from elemental analyses, thermal, infrared, ¹H NMR, electronic spectra, magnetic susceptibility and conductivity measurements. The richness of electronic spectral in these complexes is also supporting evidence for the trinuclearity of the Ni(II) polymer complexes.

Polymer complexes: XLX. Novel supramolecular coordination modes of structure and bonding in polymeric hydrazone sulphadrugs uranyl complexes

Novel five binuclear polymeric dioxouranium(VI) of azosulphadrugs [(azodrug substances) azobenzene sulphonamides] were prepared for the first time. The infrared spectra of the samples were recorded and their fundamental vibration wave number was obtained. The resulting polymeric uranyl complexes were characterized on the basis of their elemental analyses, conductance and spectral (IR, NMR, and electronic spectra) data. The ligation modes of the azosulphadrugs ligands towards uranyl(II) ions were critically assigned and addressed properly on the basis of their IR and their uranyl(II) complexes. The theoretical aspects are described in terms of the well-known theory of 5d-4f transitions. The coordination geometries and electronic structures are determined from a framework for the modeling of novel polymer complexes. The values of nu(3) of the prepared complexes containing UO(2)(2+) were successfully used to calculate the force constant, F(UO) (1n 10(-8)N/A) and the bond length R(UO) of the U-O bond. Wilson's, matrix method, Badger's formula, and Jones and El-Sonbati equations were used to calculate the U-O bond distances from the values of the stretching and interaction force constants. The most probable correlations between U-O force constant to U-O bond distance were satisfactorily discussed in terms of "Badger's rule", "Jones" and "El-Sonbati equations".

Polymer complexes: XLIX-Supramolecular modeling of bonding in novel rare earth polymeric rhodanine drug complexes

Novel supramolecular rare earth polymeric hydrazone complexes of 5-sulphadiazineazo-3-phenyl-2-thiaxo-4-thiazolidinone (HL) of the composition [(Ln)(2)(HL)(3)(NO(3))(6)](n) (where Ln = La(1), Y(2), Pr(3), Nd(4), Sm(5), Gd(6) and Ho(7)) have been prepared and characterized on the basis of their chemical analyses, magnetic measurements, conductance, visible and IR spectral data. Composition, conductance and IR spectral data of complexes show that all these act as a tetradentate ligand. Electronic spectra indicate weak covalent character in the metal-ligand bond. The spectra of Nd(3+) and Ho(3+) show characteristic f-f transitions and the metal-ligand covalency in % has been evaluated. The spectral properties of the above polymeric complexes are also discussed.

Stereochemistry of new nitrogen containing heterocyclic compound XII. Polymeric uranyl complexes of hydrazone compounds

Several dioxouranium(VI) heterochelates with tetradentate monobasic hydrazone compounds (HL(n)) have been synthesized. The heterochelates of the type [(UO2)2(HL(n))(L(n))2(OAc)2(OH2)2]n have been characterized on the basis of elemental analyses, IR and electronic spectra, conductance and magnetic susceptibility measurements. The complexes are polymeric, non-electrolytes, diamagnetic and eight-coordinated. Wilson, G.F. matrix method, Badger's formula, Jones and El-Sonbati equations were used to determine the stretching and interaction force constants from which the U-O bond distances were calculated. The bond distances of these complexes were also investigated.

Structural model of dioxouranium(VI) with hydrazono ligands

Synthesis and characterization of several new coordination compounds of dioxouranium(VI) heterochelates with bidentate hydrazono compounds derived from 1-phenyl-3-methyl-5-pyrazolone are described. The ligands and uranayl complexes have been characterized by various physico-chemical techniques. The bond lengths and the force constant have been calculated from asymmetric stretching frequency of OUO groups. The infrared spectral studies showed a monobasic bidentate behaviour with the oxygen and hydrazo nitrogen donor system. The effect of Hammett's constant on the bond distances and the force constants were also discussed and drawn. Wilson's matrix method, Badger's formula, Jones and El-Sonbati equations were used to determine the stretching and interaction force constant from which the UO bond distances were calculated. The bond distances of these complexes were also investigated.

Stereochemistry of new nitrogen containing heterocyclic aldehyde. Part XI. Novel ligational behaviour of quinoline as chelate ligand toward transition metal ions

Novel complexes of Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II) and UO2(II) with a new Schiff base derived from 8-hydroxy-7-quinolinecarboxaldehyde and 2-aminoethanethiol (LH2) (system name: 2-(8-hydroxy-7-carboxalimino)ethanethiol.) have been prepared and characterized on the basis of analytical, thermal, magnetic moment, infrared, electronic, NMR and EPR spectral data. From the analytical, NMR and thermal data and stoichiometry of the complexes indicate that LH2 act as a dibasic tridentate ligand with ONS donors towards all the metal ions. The magnetic moment, electronic and EPR spectral data commensurate that the Mn(II), Fe(II), Ni(II) and UO2(II) complexes are dimeric with octahedral configuration while the Cu(II) and Zn(II) complexes are monomeric with square-planar and tetrahedral geometries, respectively. Various ligand field parameters Dq, B and beta for complex 5 was calculated. The complexes 3+4 have lower symmetries and the amount of distortion in terms of DT/DQ applying NSH "Hamiltonian Theory" has been evaluated which indicate that the complexes are moderately distorted.

Stereochemistry of new nitrogen containing heterocyclic compounds.; X. Supramolecular structures and stereochemical versatility of polymeric complexes

New polymeric complexes of Cu(II), Co(II), Ni(II) and UO2(II) with 5-(2(1)-carboxyphenylazo)-8-hydroxyquinoline (LH2) have been prepared and characterized on the basis of analytical, magnetic, 1H NMR, EPR and electronic spectral studies. Tentative structures for the polymeric complexes are proposed. The important infrared (IR) bands and the main 1H NMR signals are assigned and discussed relative to the molecular structure. EPR spectrum of copper(II) complex has been studied with a view to assigning their stereochemistries. Various EPR parameters have been calculated. Each metal has six-coordinates in an octahedral environment. The ligand acts as a dibasic (bis-bidentate chelating agent coordinating through CN, N=N, COOH and OH groups by replacement of a proton from the two latter groups. Considerable interest has also been focused on the synthesis of the azo compounds and its polymeric metal complex due to its wide potential applications. The thermal decomposition behavior of the complexes is also discussed.

Substituents effect on the spectral studies on rutheninum(III) complexes of 5(-4'-derivatives phenyldiazo)-3-phenyl-2-thioxo-4-thiazolidinone

A novel series of Ru(III) complexes with 5(-4'-derivatives phenyldiazo)-3-phenyl-2-thioxo-4-thiazolidinone (HLn) have been prepared. The ligands and structural composition of complexes were confirmed and characterized by various physico-chemical techniques. The spectral data were utilized to compute the important ligand field parameters B, beta and Dq. The effect of Hamett's constant on the ligand field parameters is also discussed. The spectral and magnetic results commensurate an octahedral environment around the Ru(III) ion. The B-values suggest a strong covalency in the metal-ligand sigma-bond and the Dq-values indicate a medium-strong ligand-field. IR spectra show that the ligand is neutral bidentate forming thereby a six-membered chelating ring and concomitant formation of an intramolecular hydrogen bond. The ligands are present in associated form in solution via intermolecular hydrogen bond and act as neutral bidentate coordinated to ruthenium(III).

Stereochemistry, structural and models of novel 5-(4'-derivatives phenyldiazo)-3-phenyl-2-thioxo-4-thiazolidinone complexes

Copper(II) and cadmium(II) complexes of 5-(4'-derivatives phenyldiazo)-3-phenyl-2-thioxo-4-thiazolidinone (HLn) were prepared, their compositions and physicochemical properties were characterized by elemental analysis, magnetic suseptibility measurements, and infrared, electronic spectra. The novel complexes have the stoichiometric formulae [Cu(HLn)(OAc)n(H2O)(X)] (OAc = acetate, X = H2O or acetate) and [Cd(L)(OAc)(H2O)], respectively. Elemental analysis and IR spectra denote, that two types of complexes with different octahedral and tetrahedral structure for Cu(II) and Cd(II) ions. I.R. spectra show that the ligand is monobasic/neutral bidentate forming thereby a six-membered chelating ring and concomitant formation of an intramolecular hydrogen bond. The stoichiometeries of these complexes were determined conductometrically and indicated the formation of 1:1 and 1:2 (metal:ligand) complexes.

Coordination modes of novel rhodanine azodye complexes

The reaction products of metal(II) salts with 5-sulphamethoxazoleazo-3-phenyl-2-thioxo-4-thiazolidinone (H2L) have been characterized by elemental analyses, magnetic susceptibility, electronic, infrared and electron paramagnetic resonance spectral measurements. The spectral data suggest a square pyramidal structure for Cu(II) and Co(II) complexes and an octahedral for Ni(II) complexes. Various EPR parameters have been calculated. From the electron paramagnetic resonance and spectral data, the orbital reduction factors were calculated. In all case kperpendicular > kparallel which indicates a 2B1g ground state. These five coordinated complex of Cu(II) react further with pyridine forming six coordinate base adduct. The different modes of chelation of the ligand and stereochemistry around the metal ion are discussed.

Stereochemistry of new nitrogen containing heterocyclic aldehyde. VII. Potentiometric, conductometric and thermodynamic studies of novel quinoline azodyes and their metal complexes with some transition metals

A novel series of quinoline azodyes (5-(4'-derivatives phenyldiazo)-8-hydroxy-7-quinolinecarboxaldehyde)) (HL1-HL5) has been prepared and characterized by elemental analyses, 1H-NMR and IR spectra. The IR spectral data indicate that the compounds can exist in two resonance structures. Proton-ligand dissociation constants of quinoline azodyes and their subsituted derivatives, and metal-ligand stability constants of their complexes with bivalent (Mn2+, Co2+, Ni2+, Cu2+) metal ions have been determined potentiometrically in 0.1 m KCl and 40% (v/v) dimethylformamide (DMF)-water mixture. The influence of substituents on the dissociation and stability constants was examined on the basis of the electron repelling property of the substituent. The order of the stability constants of the formed complexes was found to be Mn2+ < Co2+ < Ni2+ < Cu2+. The effect of temperature was studied and the corresponding thermodynamic parameters (deltaG, deltaH, deltaS) were derived and discussed. The stoichiometries of these complexes were determined conductometrically and indicated the formation of 1:1 and 1:2 (metal:ligand) complexes was indicated.