Reactions of (η5-C5H5)2Tir compounds with organic cyanides

The syntheses and properties of the titanium(III) complexes Cp₂Tir · R′CN (R = C₆H₅, o-, m-, p-CH₃C₆H₄, CH₂C₆H₅, C₆F₅, Cl; R′ = CH₃, t-C₄H₉, C₆H₅, o-CH₃C₆H₄, 2,6-(CH₃)₂C₆H₃) are described. In the complexes the nitrogen atom of the cyanide ligands is coordinated to the metal. The thermal stabilities of the complexes depend markedly on R and R′; on heating they undergo a novel reaction in which two cyanide ligands are coupled by formation of a CC bond, while the metal is oxidized to titanium(IV).     

Kinetische untersuchungen an carbonyl(diorganyldithiophosphinato)-komplexen des mangans und rheniums

The substitution reactions of monomeric dithiophosphinato complexes R₂ PS₂ M(CO)₄ (R = C₂ H₅, C₆H₅; M = Mn, Re) with monodentate ligands P(C₆H₅)₃, As(C₆H₅)₃ and pyridine are examined kinetically. The reactions with P(C₆H₅)₃ and pyridine follow first-order and those with As(C₆H₅)₃ second-order kinetics. The rate constants as well as activation parameters are calculated and discussed in detail together with the reaction mechanism.     

Ligand Site Preference in Iron Tetracarbonyl Complexes Fe(CO)4L (L = CO,CS, N2, NO+, CN–, NC–, η2‐C2H4, η2‐C2H2, CCH2, CH2, CF2, NH3, NF3, PH3, PF3, η2‐H2)

Equilibrium geometries, bond dissociation energies and relative energies of axial and equatorial iron tetracarbonyl complexes of the general type Fe(CO)₄L (L = CO, CS, N2, NO⁺, CN^–, NC^–, η²‐C₂H₄, η²‐C₂H₂, CCH₂, CH₂, CF₂, NH₃, NF₃, PH₃, PF₃, η²‐H₂) are calculated in order to investigate whether or not the ligand site preference of these ligands correlates with the ratio of their σ‐donor/π‐acceptor capabilities. Using density functional theory and effective‐core potentials with a valence basis set of DZP quality for iron and a 6‐31G(d) all‐electron basis set for the other elements gives theoretically predicted structural parameters that are in very good agreement with previous results and available experimental data. Improved estimates for the (CO)₄Fe–L bond dissociation energies (D₀) are obtained using the CCSD(T)/II//B3LYP/II combination of theoretical methods. The strongest Fe–L bonds are found for complexes involving NO⁺, CN^–, CH₂ and CCH₂ with bond dissociation energies of 105.1, 96.5, 87.4 and 83.8 kcal mol^–1, respectively. These values decrease to 78.6, 64.3 and 64.2 kcal mol^–1, respectively, for NC^–, CF₂ and CS. The Fe(CO)₄L complexes with L = CO, η²‐C₂H₄, η²‐C₂H₂, NH₃, PH₃ and PF₃ have even smaller bond dissociation energies ranging from 45.2 to 37.3 kcal mol^–1. Finally, the smallest bond dissociation energies of 23.5, 22.9 and 18.5 kcal mol^–1, respectively are found for the ligands NF₃, N₂ and η²‐H₂. A detailed examination of the (CO)₄Fe–L bond in terms of a semi‐quantitative Dewar‐Chatt‐Duncanson (DCD) model is presented on the basis of the CDA and NBO approach. The comparison of the relative energies between axial and equatorial isomers of the various Fe(CO)₄L complexes with the σ‐donor/π‐acceptor ratio of their respective ligands L thus does not generally support the classical picture of π‐accepting ligands preferring equatorial coordination sites and σ‐donors tending to coordinate in axial positions. In particular, this is shown by iron tetracarbonyl complexes with L = η²‐C₂H₂, η²‐C₂H₄, η²‐H₂. Although these ligands are predicted by the CDA to be stronger σ‐donors than π‐acceptors, the equatorial isomers of these complexes are more stable than their axial pendants.     

Effect of the hydrogen peroxide concentration in stereospecific oxidation of alkanes by models of non-heme oxygenases

The biomimetic oxidation of alkanes (cyclohexane, adamantane, cis-1,2-dimethylcyclohexane) with hydrogen peroxide catalyzed by Fe(II) complexes containing tetradentate nitrogen ligands (M = [Fe(bpmen)(MeCN)₂](ClO₄)₂ (bispicolyl-1,2-dimethylethylenediamine), [Fe(bpen)(MeCN)₂](ClO₄)₂ (bispicolylethylenediamine), and [Fe(tpcaH)(MeCN)₂]₂(ClO₄)₄ (tripyridylcarboxamide) is studied. The effects of the hydrogen peroxide concentration on the alcohol/ketone (A/K) ratio and on the regioselectivity of oxidation (3/2) are discovered. Rather high stereospecificity (RC = 96–99%) persisting at high hydrogen peroxide concentrations is hardly consistent with the participation of the HO^. radical, inferred from the rather low regioselectivity and low A/K ratio observed under these conditions. The molecular mechanism of oxygen transfer from hydrogen peroxide, which was earlier proved reliably for low concentrations of hydrogen peroxide ([H₂O₂]/[M] ? 10), can be applied to high peroxide concentrations ([H₂O₂]/[M] > 10) if a new ferryl species containing two equivalents of the oxidant is assumed to be involved in the process. This assumption is confirmed by the direct stereospecific formation of alkyl hydroperoxide from alkane at a high concentration of hydrogen peroxide.     

New Dinuclear Ru2(CO)4 Sawhorse‐Type Complexes Containing Bridging Carboxylato Ligands

The thermal reaction of Ru₃(CO)₁₂ with ethacrynic acid, 4‐[bis(2‐chlorethyl)amino]benzenebutanoic acid (chlorambucil), or 4‐phenylbutyric acid in refluxing solvents, followed by addition of two‐electron donor ligands (L), gives the diruthenium complexes Ru₂(CO)₄(O₂CR)₂L₂ ( 1 : R = CH₂O‐C₆H₂Cl₂‐COC(CH₂)C₂H₅, L = C₅H₅N; 2 : R = CH₂O‐C₆H₂Cl₂‐COC(CH₂)C₂H₅, L = PPh₃; 3 : R = C₃H₆‐C₆H₄‐N(C₂H₄‐Cl)₂, L = C₅H₅N; 4 : R = C₃H₆‐C₆H₄‐N(C₂H₄‐Cl)₂, L = PPh₃; 5 : R = C₃H₆‐C₆H₅, L = C₅H₅N; 6 : R = C₃H₆‐C₆H₅, L = PPh₃). The single‐crystal structure analyses of 2 , 3 , 5 and 6 reveal a dinuclear Ru₂(CO)₄ sawhorse structure, the diruthenium backbone being bridged by the carboxylato ligands, while the two L ligands occupy the axial positions of the diruthenium unit.     

Iron(I)-Based Carbonyl Complexes with Bridging Thiolate Ligands as Light-Triggered CO Releasing Molecules (photoCORMs)

A series of thiolate ligands were used to synthesize diiron(I) hexacarbonyl bis(thiolates) for structural studies. Conversion of the corresponding thiols with triiron(0) dodecacarbonyl yields complexes of the type [{(CO)₃Fe(μ-SR)}₂] [R = C₆H₅ ( 1 ), C₆H₄-4-CH₃ ( 2 ), C₆H₄-4-F ( 3 ), C₆F₅ ( 4 ), C₆H₄-4-CF₃ ( 5 ), C₆H₂-2,4,6-(CH₃)₃ ( 6 ), CH₂–C₆H₄-4-Cl ( 7 )]. These complexes were isolated and fully characterized, including X-ray crystal structures of complexes 2 – 7 . The bridging thiolate ligands mainly influence the Fe–CO bond which is trans-positioned to the second iron(I) center. In solution, the anti-isomer with one axially and one equatorially oriented thiolate is the major species; severe steric strain induced by mesityl groups only allows the formation of syn-endo-isomeric molecules of 7 . Furthermore, light-induced CO release at solid material at the three representative complexes 1 , 3 , and 6 verify suitability as photoCORMs.     

SYNTHESIS AND CHARACTERISATION OF DIORGANOANTIMONY(III) COMPLEXES OF THIOSEMICARBAZONES

Abstract

The interaction of the sodium salts of thiosemicarbazones with diphenylantimony chloride in 1:1 molar ratio in benzene solution lead to the formation of derivatives, Ph₂Sb[SC(NH₂)NN: C(R)R′] where R = H; R′ [dbnd] C₆H₅, CH₃OC₆H₄, C₆H₅CH[dbnd]CH, and R′ [dbnd] CH₃; R′[dbnd]C₆H₅, CH₃OC₆H₄, C₆H₄CH₃, respectively. The resulting complexes have been characterised on the basis of elemental analyses and molecular weight determination. The mode of bonding of the ligands with the metal atom has been proposed on the basis of I.R., ¹H and ¹³C NMR studies. All these ligands are found to behave as monofunctional bidentate moiety in these complexes.     

Monophosphine‐substituted diiron azadithiolate complexes: New syntheses,characterization and electrochemical properties

Investigating the synthesis and properties of diiron azadithiolate complexes is one of the key topics for mimicking the active site of [FeFe]‐hydrogenases, which might be very useful for the design of new efficient catalysts for hydrogen production and the development of a future hydrogen economy. A series of new phosphine‐substituted diiron azadithiolate complexes as models for the active site of [FeFe]‐hydrogenases are described. A novel and efficient way was firstly established for the preparation of phosphine‐substituted diiron azadithiolate complexes. The reaction of Fe₂(μ‐SH)₂(CO)₆ and phosphine ligands L affords the intermediate Fe₂(μ‐SH)₂(CO)₅L ( A ). The intermediate reacts in situ with a premixed solution of paraformaldehyde and ammonium carbonate to produce the target phosphine‐substituted diiron azadithiolate complexes Fe₂[(μ‐SCH₂)₂NH](CO)₅L ( 1a – 1f ) (L = P(C₆H₄–4‐CH₃)₃, P(C₆H₄–3‐CH₃)₃, P(C₆H₄–4‐F)₃, P(C₆H₄–3‐F)₃, P(2‐C₄H₃O)₃, PPh₂(OCH₂CH₃)). Furthermore, reactions of the intermediate A with I‐4‐C₆H₄N(CH₂Cl)₂ in the presence of Et₃N give the phosphine‐substituted diiron azadithiolate complexes Fe₂[(μ‐SCH₂)₂NC₆H₄–4‐I](CO)₅L ( 2a – 2e ) (L = P(C₆H₄–4‐CH₃)₃, P(C₆H₄–3‐CH₃)₃, P(C₆H₄–4‐F)₃, P(C₆H₄–3‐F)₃, P(2‐C₄H₃O)₃). All the complexes were fully characterized using elemental analysis, IR and NMR spectroscopies and, particularly for 1a , 1c – 1e , 2a and 2c , single‐crystal X‐ray diffraction analysis. In addition, complexes 1a – 1f and 2a – 2e were found to be catalysts for H₂ production under electrochemical conditions. Density functional theory calculations were performed for the reactions of Fe₂(μ‐SH)₂(CO)₆ + P(C₆H₄–4‐CH₃)₃.     

Hydrogen adsorption on Ti containing organometallic structures grafted on silsesquioxanes

The adsorption of hydrogen molecule on a novel structure of Ti containing organometallic complexes grafted on silsequioxanes (SQ, H₈Si₈O₁₂) was investigated by means of DFT method. The hydrogen adsorption properties of the complex structures TiRH₇Si₈O₁₂ (R = C₄H₃, C₅H₄, C₆H₅) keep almost the same as that of corresponding Ti containing organometallic complexes. Moreover, these complex structures can avoid the problem of transition metal clustering which is a disadvantage for hydrogen adsorption. The maximum number of hydrogen molecules adsorbed was still determined by 18 electron rule, that is to say 5, 4, and 4 H₂ molecules for TiRH₇Si₈O₁₂ with R = C₄H₃, C₅H₄, and C₆H₅, respectively. At the same time, all the average binding energy of H₂ is located in 0.2–1.0 eV, which is an advantage for hydrogen storage at ambient conditions. Therefore, the materials studied here may provide some enlightenment for developing new types of hydrogen storage materials.     

Diphenylbenchrotrenylphosphine - a new two-electron ligand in carbonyl-containing π-aromatic chromium and manganese complexes and in carbonyls of group vib metals

Photochemical substitution of CO ligands in C₆H₆Cr(CO)₃, C₅H₅Mn(CO)₃ and M(CO)₆ (M = Cr, Mo, W) for PPh₂C₆H₅Cr(CO)₃, ligands was used to synthesize novel complexes: C₆H₆Cr(CO)₂PPh₂C₆H₅Cr(CO)₃, C₅H₅Mn(CO)₂PPh₂C₆H₅Cr (CO)₃ and M(CO)₅PPh₂C₆H₅Cr(CO)₃.The complexes obtained have been characterized by elemental analysis, IR, ¹H, ¹³C, ³¹P NMR, and mass spectra.The protonation reaction and the hydrogen isotopic exchange of arenechromium carbonyl complexes in acid media have been studied.The ¹³C NMR spectra of M(CO)₅PPh₂C₆H₅Cr(CO)₃ show that the nature of the central metal atom influences the chemical shifts of the carbon nuclei of the carbonyl groups, shielding these atoms, increasing in the series W ⩽ Mo < Cr.     

Iron(II) Complexes of Chiral Tridentate Nitrogen Donors and their Application in Catalytic Hydrosilylation Reactions

Enantiomerically pure, C₂-symmetric 2,6-bis(pyrazol-3-yl) pyridine ligands were obtained by treatment of diethyl-2,6-pyridinedicarbonate with (1R,4R)-(+)-camphor in the presence of NaH followed by ring closure with hydrazine. After twofold N-alkylation at the pyrazole rings, the addition of iron(II) chloride led to the according pentacoordinate dichloridoiron(II) complexes. All intermediates of the ligand synthesis, the ligands bearing NCH₃ and NCH₂C₆H₅ groups and the derived iron(II) complexes were structurally characterized by means of X-ray structure analysis. In-situ reaction with iron(II) carboxylates resulted in the formation of iron(II) carboxylate complexes, which turned out to be highly active in the hydrosilylation of acetophenone. However, even at room temperature, the enantiomeric excess of the product 1-phenylethanol is poor. ⁵⁷Fe Mössbauer spectroscopy gave an insight into the species formed during catalysis.     

Monocyclopentadienyl titanium(IV) alkyl xanthate complexes

Titanium(IV) alkyl xanthates of the types CpTi(S₂COR)Cl₂, CpTi(S₂COR)₂Cl and CpTi(S₂COR)₃, where R = CH₃, C₂H₅, C₃H₇, C₄H₉ and C₅H₁₁, have been prepared by the reaction of monocyclopentadienyl titanium(IV) trichloride with potassium alkyl xanthates in anhydrous dichloromethane. Conductance and infrared studies suggest that these complexes are non-electrolytes in which all of the xanthate ligands are bidentate. Proton nmr spectra of these complexes indicate that there is rapid rotation of the cyclopentadienyl ring about the metal-ring axis and for the CpTi(S₂COR)₃ complexes non-equivalence of the alkylxanthate ligands was observed.     

Mixed-ligand iridium(IV) complexes with amino acids,adenine and hypoxanthine

The complexation in iridium(IV)-purine base (adenine, hypoxanthine)-amino acid (α-alanine, aspartic acid, lysine) systems was studied by pH titration. The stability constants of 1: 1: 1 complexes were determined. The stability of 1: 1: 1 mixed-ligand complexes with hypoxanthine and adenine increases in the series Ala < Lys < Asp. Reactions between aqueous solutions gave the following coordination compounds: [Ir(C₅H₄N₄O)(C₃H₆NO₂)Cl]Cl₂, [Ir(C₅H₄N₄O)(C₄H₅NO₄)]Cl₂, [Ir(C₅H₄N₄O)(C₆H₁₃N₂O₂)]Cl₃, [Ir(C₅H₅N₅)(C₃H₆NO₂)]Cl₃, [Ir(C₅H₅N₅)(C₄H₅NO₄)]C_l2, and [Ir(C₅H₅N₅)(C₆H₁₃N₂O₂)]Cl₃. The individual character of the complexes was established by chemical and thermogravimetric analyses and powder X-ray diffraction. The complexes were characterized by NMR, IR, and X-ray photoelectron spectroscopy. Alanine and lysine in mixed-ligand iridium(IV) complexes are bidentate (α-NH₂ and COO⁻ groups), aspartic acid is tridentate, and purine bases function as polydentate ligands through heterocycle N atoms and functional groups (NH₂ in adenine and C=O in hypoxanthine).     

NMR,IR and DFT studies of phenylplatinum complexes with O-monodentate coordinated silsesquioxanate and auxiliary phosphine ligands

The molecular structure and spectroscopic properties of a series of phenylplatinum complexes containing silsesquioxanate and phosphine ligands with general formula trans-[Pt{O₁₀Si₇(R)₇(OH)₂}(Ph)(L)₂] (1: R = cyclo-C₅H₉, L = PEt₃; 2: R = iso-C₄H₉, L = PEt₃; 3: R = CH₃, L = PEt₃; 4: R = cyclo-C₅H₉, L = PMe₃; 5: R = cyclo-C₅H₉, L = PMe₂Ph; 6: R = cyclo-C₅H₉, L = PPh₂Me; 7: R = cyclo-C₅H₉, L = PPh₃) have been investigated by DFT/OPW91/6-31G(d) calculations, ¹H, ¹³C, ²⁹Si and ³¹P NMR and IR spectroscopy. DFT molecular modeling based on available X-ray and NMR data for complexes 1 and 2 allowed deriving structure-NMR spectra correlations. It was found that the alkyl substituents (R) attached to Si atoms, cyclo-C₅H₉, iso-C₄H₉ and CH₃, slightly influence the geometry and multinuclear NMR parameters of the complexes in the series studied. The molecular structures of the Pt(II) complexes with R = cyclo-C₅H₉ (4–7) were predicted by DFT calculations of their simplified models with R = CH₃ (4′?7′). The geometry optimizations of 4′?7′ showed square-planar configuration of Pt(II) center bonded to two trans phosphine ligands, a phenyl group and an O-monocoordinated silsesquioxanate. The structures 4′?6′ are stabilized by two intramolecular hydrogen bonds similar to 1 and 2. A fast conformer exchange process A?B and switching of H-bonds in solution of 1–6 were suggested based on (i) the calculated conformer energies and small barrier of the process, and (ii) the observed single ¹H NMR signal at low magnetic field. The stability of the Pt(II) complexes depends on the nature of the phosphine ligands and decreases in the order PMe₂Ph > PMe₃ > PPh₂Me > PEt₃ > PPh₃. The PPh₃ ligands attached to Pt(II) in 7 cause the largest geometry changes and a new set of weaker hydrogen bonds. The comparison of the calculated NMR and IR parameters with the experimental spectroscopic data reveals good coincidence and thus confirmed the suggested molecular structures.     

Synthesis and electrochemical studies of organometallic cobalt(III) complexes with substituted benzonitrile chromophores: NMR spectroscopic data as a probe on the second-order non-linear optical properties

The family of organometallic Co(III) benzonitrile derivatives of general formula [CoCp(dppe)(p-NCR)][PF₆]₂ (R = C₆H₄NMe₂, C₆H₄NH₂, C₆H₄OMe, C₆H₄C₆H₅, C₆H₅, C₆H₄C₆H₄NO₂, and C₆H₄NO₂) have been synthesized. Spectroscopic and electrochemical data were analyzed in order to evaluate the extent of electronic coupling between the organometallic fragment and the nitrile ligands. An attempt of correlation between NMR spectroscopic data and the second-order non-linear optical properties is presented, based on this work and available published data for related η⁵-monocyclopentadienyliron, ruthenium and nickel complexes.     

Introduction of new ancillary ligands to the iridium complexes having 2,3-diphenylquinolinato ligands for OLED

We investigated the effect of an ancillary ligand (AL) on the emission color and luminous efficiencies of its complex, Ir(4-Me-2,3-dpq)₂(AL), where 4-Me-2,3-dpq represents 4-methyl-2,3-diphenylquinolinato ligand. We expected that ancillary ligand modification by introduction of the bulky substituent to the complexes might allow luminous efficiency increase by reduction of T–T annihilation. Furthermore, some ancillary ligands may contribute to fine-tuning of their complex emission colors by influencing the energy level of Ir d-orbitals upon the orbital mixing. As new ancillary ligands substituting for acac which is a typical AL in the iridium complexes, pyrazolone-based ligands, 4-R-5-methyl-2-phenyl-2,4-dihydro-pyrazol-3-one series (przl-R), were prepared, where R represents C₆H₅, C₆H₄CH₃ and C₆H₄Cl. These ligands were chelated to the iridium center to yield a new series of the iridium complexes, Ir(4-Me-2,3-dpq)₂(przl-R). The X-ray crystal structure of Ir(4-Me-2,3-dpq)₂(przl-C₆H₄Cl) was determined. The electrochemical and luminescence properties of the iridium complexes were investigated. The effect of the przl-substituents on the emission colors of the complexes was not significant. On the other hand, the luminous efficiencies of Ir(4-Me-2,3-dpq)₂(przl-C₆H₅) and Ir(4-Me-2,3-dpq)₂(przl-C₆H₄CH₃) were higher than that of Ir(4-Me-2,3-dpq)₂(acac).     

Hydrogen‐bonded complexes of 2‐pyridone with centrosymmetric and non‐centrosymmetric dicarboxylic acids

2‐Pyridone (2‐oxo­pyrimidine) forms hydrogen‐bonded com­plexes with di­carboxyl­ic acids, the molar ratio of 2‐pyridone/di­carboxyl­ic acid being 2:1 for the complexes with oxalic acid (ethanedioic acid), 2C₅H₅NO·C₂H₂O₄, (I), and trans‐β‐hydro­muconic acid (trans‐hex‐3‐enedioic acid), 2C₅H₅NO·C₆H₈O₄, (II), and 1:1 for the complexes with trans‐glutaconic acid (trans‐pent‐2‐enedioic acid), C₅H₅NO·C₅H₆O₄, (III), and l ‐­tartaric acid (l ‐2,3‐di­hydroxy­butane­dioic acid), C₅H₅NO·C₄H₆O₆·H₂O, (IV). Common features in the hydrogen‐bonding patterns were found for the centrosymmetric and non‐centrosymmetric acids, respectively. The 2‐pyridone mol­ecule takes the lactam form in these crystals.     

A five‐coordinate iron(III) porphyrin complex including a neutral axial pyridine N‐oxide ligand

While six‐coordinate iron(III) porphyrin complexes with pyridine N‐oxides as axial ligands have been studied as they exhibit rare spin‐crossover behavior, studies of five‐coordinate iron(III) porphyrin complexes including neutral axial ligands are rare. A five‐coordinate pyridine N‐oxide–5,10,15,20‐tetraphenylporphyrinate–iron(III) complex, namely (pyridine N‐oxide‐κO)(5,10,15,20‐tetraphenylporphinato‐κ⁴N,N′,N′′,N′′′)iron(III) hexafluoroantimonate(V) dichloromethane disolvate, [Fe(C₄₄H₂₈N₄)(C₅H₅NO)][SbF₆]·2CH₂Cl₂, was isolated and its crystal structure determined in the space group P. The porphyrin core is moderately saddled and the Fe—O—N bond angle is 122.08 (13)°. The average Fe—N bond length is 2.03 Å and the Fe—ONC₅H₅ bond length is 1.9500 (14) Å. This complex provides a rare example of a five‐coordinate iron(III) porphyrin complex that is coordinated to a neutral organic ligand through an O‐monodentate binding mode.     

Structure-activity relationship of some pentacoordinated Tributyltin(IV) complexes derived from sterically hindered Schiff bases of heterocyclic β-diketones

Some pentacoordinated tributyltin(IV) complexes of sterically hindered Schiff bases of heterocyclic β-diketones having the general formula Bu₃SnL (where LH = RC:NZC:C(OH)N(C₆H₅)N:CCH₃ where R = –CH₃, –C₆H₅, –C₆H₄Cl (p) and Z = –C₆H₄Cl(m), –C₆H₄Cl(p) and –C₆H₄Cl(p)] were screened for their antimicrobial activity against the bacterial strain (Bacillus subtillis) and fungal strains (Candida albicans and Aspergillas niger). These monomeric pentacoordinated tributyltin(IV) complexes possess six membered ring which provide stability to the complexes. These complexes possess Sn←N bond scaffold which impart biological activity in tributyltin(IV) complexes. Antimicrobial bioassay results reveal that these tributyltin(IV) complexes derived from sterically hindered Schiff bases of heterocyclic β-diketones were possess more inhibition potential than their respective parent ligands. These pentacoordinated tributyltin(IV) complexes may used as antibiotic drug in future.     

Chloro-diorganotin(IV) complexes of pipyridyl dithiocarbamate: Syntheses and determination of kinetic parameters, spectral characteristics and biocidal properties

Organotin complexes of the general formula R₂Sn(Cl)L have been synthesized where R = CH₃, C₂H₅, C₄H₉, C₆H₅, C₇H₇, and L = 1-piperidinecarbodithioic acid. These complexes have been characterized by elemental analysis, FT-IR, ₁H NMR and mass spectrometry. The spectroscopic and XRD data shows that the dithiocarbamate ligand acts as a bidentate ligand. These complexes were also tested for biocidal activity. Thermal studies of the reported complexes have been carried out to investigate the degradation pattern and thermal stability while kinetic parameters were calculated from the thermogravometric (TG) trace. Silent features of X-ray structures for (1) and (4) are also given.