Indazole complexes of diorganotin(IV) dihalides. The crystal structures of dichloro and dibromodimethylbis(indazole) tin(IV)

Reaction of indazole (HInd) with diorganotin(IV) dihalides yielded compounds of the type [SnR₂X₂(HInd)₂] (R = Me, Et, Bu and Ph; X = Cl, Br). The structures of the dihalodimethylbis(indazole)tin(IV) complexes were determined by X-ray crystallography. These are trans-octahedral centrosymmetric compounds with the following bond lengths (Å) around the tin atom: Sn-Cl 2.590(2), Sn-N 2.377(6), Sn-C 2.12(1) in the chloride; and Sn-Br 2.733(1), Sn-N 2.370(5) and Sn-C 2.12(1) in the bromide. Mössbauer and vibrational spectra suggest similar trans stereochemistry for the other complexes prepared. The behaviour of these compounds in solution was studied by conductimetry and NMR techniques.     

Synthesis and structural characterization of organotin(IV) carboxylates based on different heterocyclic substituents

Six novel organotin(IV) carboxylates have been successfully synthesized, namely, the polymer (C₆H₅)₃Sn(L1)_∞ (1) [HL1 = 4-imidazolyl benzoic acid], the mononuclear (C₆H₅)₃Sn(L2) (2) [HL2 = 4-pyrazolylbenzoic acid], (C₆H₅)₃Sn(L3)·CH₃OH (3) [HL3 = 4-triazolylbenzoic acid] and (C₆H₅)₃Sn(L4) (4) [HL4 = 4-tetrazolyl benzoic acid] and the tetranuclear [(n-Bu₂Sn)₄(L2)₂O₂(OCH₃)₂] (5) and [(n-Bu₂Sn)₄(L3)₂O₂(OCH₃)₂] (6). X-ray diffraction analyses show 1D infinite chain of polymer 1, single molecular structures of isomorphous complexes 2 and 4, single molecule structures of complex 3 containing solvent CH₃OH molecule and similar ladder-type structures of complexes 5 and 6. The photoluminescence of ligands and 1-6 were also measured in the solid state at room temperature.     

Use of bis-aminoalcohol benzoquinones and dihydroxybenzoquinones in the formation of mono and polymeric structures of diorganotin(IV) derivatives

Reaction of three hexadentate ligands (L1-L3) derived from 1,4-benzoquinone bis(aminoalcohols) with diorganotin oxides (R₂Sn-O)_n (with R = Me, nBu, Ph) in 1:2 stoichiometric proportions lead to the formation of dinuclear tin compounds of the composition [(R₂Sn)₂(L)], wherein the five-coordinate metal centers are embedded in distorted trigonal-bipyramidal polyhedra. X-ray diffraction analysis revealed that diorganotin complexes carrying n-butyl groups tend to associate further through intermolecular O?Sn interactions to give 1D polymeric chains, while diphenyltin analogues tend to be monomeric. On the other hand, using 2,5-dihydroxy-3,6-dichloro-1,4-benzoquinone as ligand (L4) in 1:1 reactions with the diorganotin oxide derivatives, 1D polymeric complexes of the composition [R₂Sn(L4)(DMSO)]_n with seven-coordinate metal centers in distorted pentagonal-bipyramidal coordination polyhedra were obtained. In this case, the presence of different substituents attached to the tin atoms (Me, nBu, Ph) had no influence on the molecular composition of the products, but on the conformation of the polymeric chain, which was either planar (R = Me), slightly distorted from planarity (R = nBu) or ondulated (R = Ph).     

Synthesis and spectral studies of diorganotin(IV) dialkyldithiophosphates

Two series of diorganotin(IV) dialkyldithiophosphates, [RR′Sn{SSP(OR″)₂}₂](R = Me or Et; R′= Ph; R″ = Et, Prⁿ, Prⁱ or Buⁿ) and [RR′Sn(Cl){SSP(OR″)₂}] (R = R′= Me, Et or Ph; R″ = Ph; R″ = Et, Prⁱ or Buⁿ) were prepared and characterised by i.r. and NMR (¹H, ¹³C, ³¹P, ¹⁹⁹Sn) spectroscopy. The NMR data indicate five and six coordinate geometries for [RR′Sn(Cl){SSP(OR″)₂}] and [RR′Sn{SSP(OR″)₂}₂] complexes, respectively. The chloro complexes showed ²J (PSn) whereas such couplings were not observed in the spectra of [RR′Sn{SSP(OR″)₂}₂].     

Preparation and spectroscopic studies of diorganotin(IV) complexes with adenosine and related compounds

Nine complexes of adenosine and related compounds (adenosine-5'-monophosphate, adenosine-5'-triphosphate, 1-methyl-adenosine, pyridoxal-5-phosphate and -nicotinamide-adenine-dinucleotide-phosphoric acid) with di-n-butyltin(IV) oxide and/or di-n-butytin(IV) dichloride were prepared in the solid state. The compositions of the complexes were determined by standard analytical methods. It was found that the complexes contain organotin(IV) moiety and the ligand in a ratio of 1:1 or 2:1. The FTIR spectra demonstrated that di-n-butyltin(IV) oxide reacts with the D-ribose moiety of the ligands, while di-n-butyltin(IV) dichloride is co-ordinated to the deprotonated phosphate group. The basic part of the ligands does not participate directly in complex formation. Comparison of the experimental Mössbauer QS values with those calculated on the basis of the PQS concept revealed that the organotin(IV) moiety has trigonal-bipyramidal, octahedral and in some cases tetrahedral geometry also. Some of the complexes contain the organotin(IV) cation in two different surroundings.     

Synthesis and spectroscopic studies on organotin(IV) complexes of some pyrazoles and pyrazol-5-ones and their antibacterial activity

A series of organotin(IV) complexes of the general formula R_xSnCl_4?x.L (where R=Me, n?Bu, Ph; x = 2 or 3; L = pyrazole or pyrazol-5-one) have been prepared and characterized by elemental analyses, IR and NMR spectroscopy. The ligands used were found to coordinate with R₃SnCl species as monodentate ligands via the more reactive nitrogen atom, to give pentacoordinate tin complexes, whilst they may coordinate with R₂SnCl₂ species as bidentate ligands through the N–N linkage to give hexacoordinate tin complexes. These were demonstrated mainly by spectroscopic data. The tautomeric behaviour of organotin complexes of pyrazol-5-one ligands in inert (CDCl₃) and donor (DMSO-d₆) solvents were also studied. The complexes were screened against six species of bacteria.     

Synthesis and spectroscopic studies of new organotin(IV) complexes with tridentate N- and O-donor Schiff bases

The Schiff bases H₂L¹ and H₂L² have been prepared by the reaction of 2-amino-4-chlorophenol with pyrrole-2-carbaldehyde and 2-hydroxy-1-naphtaldehyde, respectively, and HL³ from reaction of 2-(aminomethyl)pyridine with 2-hydroxy-1-naphtaldehyde. Organotin complexes [SnPh₂(L¹)] (1), [SnPh₂(L²)] (2), [SnMe₂(L²)] (3) and [SnPhCl₂(L³)] (4) were synthesized from reaction of SnPh₂Cl₂ and SnMe₂Cl₂ with these Schiff bases. The synthesized complexes have been investigated by elemental analysis and FT-IR, ¹H NMR and ¹¹⁹Sn NMR spectroscopy. In complexes the Schiff bases are completely deprotonated and coordinated to tin as tridentate ligands via phenolic oxygen, pyrrolic, and imine nitrogens in 1, two phenolic oxygens and imine nitrogen in 2 and 3, and phenolic oxygen, imine and pyridine nitrogens in 4. The coordination number of tin in 1, 2, and 3 is five and in 4 is six.     

Photophysical studies on multichromophoric cyclotriphosphazenes. Trinuclear excimer formation in hexakis(2-naphthyloxy)cyclotriphosphazene

Hexakis(2-naphthyloxy)cyclotriphosphazene showed an interesting emission behavior between its monomer and excimer forms, the latter nearly completely dominating in water. Encapsulation studies with β-cyclodextrin in water partially revived the monomer emission.     

Crystal Engineering with Oxo‐ and Cyanocarbon Anions: Synthesis and Structural Characterization of Triorganotin(IV) Pentacyanopropenides and Hexacyanoazapentadienides

The first triorganotin(IV) pentacyanopropenides, [R₃Sn(H₂O)₂][C₃(CN)₅] (R = Me ( 2 ), nBu ( 3 ), Ph ( 4 ) were prepared by treatment of Ag[C₃(CN)₅] ( 1 ) with equimolar amounts of R₃SnCl in reagent grade THF. In a similar manner, dark red [R₃Sn(H₂O)₂][N{C(CN)C(CN)₂}₂] ( 6 ) containing the hexacyanoazapentadienyl anion was prepared in 55 % yield. The molecular structure of [Ph₃Sn(H₂O)₂][C₃(CN)₅] ( 4 ) was determined by X‐ray diffraction. The crystal structure consists of separated trigonal‐bipyramidal [Ph₃Sn(H₂O)₂]⁺ cations and nearly planar [C₃(CN)₅]^– anions which are linked through O–H ··· N hydrogen bonds to give a three‐dimensional network.     

Syntheses and crystal structures of diorganotin (IV) moieties with 3-hydroxy-2-pyridinecarboxylic acid

A series of new organotin (IV) complexes with 3-hydroxy-2-pyridinecarboxylic acid (3-OH-2-picH) of two types: R₂SnCl(3-OH-2-pic) (I) (R = Me 1, n-Bu 2, Ph 3, PhCH₂4) and R₂ Sn(3-OH-2-pic)₂ (II) (R = Me 5, n-Bu 6, Ph 7, PhCH₂8)have been synthesized by reactions of diorganotin (IV) dichloride with 3-hydroxy-2-pyridinecarboxylic acid in the presence of sodium ethoxide. All complexes are characterized by elemental analyses, IR spectra and NMR spectra analyses. Among them, complexes 1, 5, 6 and 7 are also characterized by X-ray crystallography diffraction analyses. Complex 1 is a 1D polymeric chain with six-coordinate tin atoms and the packing of complex 1 is stabilized by the C-H?Cl intermolecular weak interactions, thus a 2D network of 1 is formed. Complex 5 is also a 1D polymeric chain with seven-coordinate tin atoms. Complex 6 is a zigzag polymeric chain linked by Sn?O intermolecular weak interactions. Complex 7 is a monomeric complex with distorted octahedral geometry.     

Double O,C,O-chelated diorganotin(IV) derivatives

Novel diorganotin(IV) compounds (L^1,2)₂SnCl₂, where L^1,2 are O,C,O-chelating ligands (called the pincer ligands), 2,6-bis(alkoxymethyl)phenyl-, , (L¹, R = Me, L², R = t-Bu), have been synthesized and characterized by ¹H, ¹³C and ¹¹⁹Sn NMR spectroscopy, MS-ESI spectrometry and elemental analysis. The structure of both compounds (L¹)₂SnCl₂ (1) and (L²)₂SnCl₂ (2) was determined by X-ray crystallography. Determination of crystal structures reveals different shapes of coordination polyhedra. While deformed octahedron was found for 1, tetrahedral geometry of the tin atom was determined for 2. The NMR spectroscopy indicates a similar structural arrangement of 1 and 2 in solution. The reaction of 1 with silver salts of low nucleophilic anions X⁻ (X = OTf and 1-CB₁₁H₁₂) resulted in (L¹)₂SnCl(OTf) (3), (L¹)₂Sn(OTf)₂ (4), and (L¹)₂SnCl(CB₁₁H₁₂) (5). The compounds 4 and 5 are of ionic nature both in solid state and in solution of CH₃CN.     

Semi-empirical MNDO study of the structure of some diorganotin (IV) glycylglycinates

The geometrical structures of some diorganotin glycylglycinates have been obtained using the MNDO semi-empirical method. A good agreement with the experimental diffractometric data was found.     

Synthesis and spectroscopic investigation of adducts of diorgano tin(IV) dichloride

Adducts of bis-p-biphenyl tin(IV) dichloride of types (p-C₆H₅-C₆H₄)₂SnCl₂·2L and (p-C₆H₅-C₆H₄)₂SnCl₂·L₁ (where 2L = pyridine, piperidine, α-, β- or γ-picolines, isoquinoline or morpholine and L₁ = 2,2′-bipyridine or 1,10 phenanthroline) have been prepared by the reaction of bis-p-biphenyl tin(IV) dichloride with the corresponding ligand in 1:2 and 1:1 molar ratios in acetone. IR, ¹H NMR and Mössbauer studies indicate that the biphenyl group occupies in the trans position, except in morpholine, where it is in the cis position.     

Synthesis and solid-state spectroscopic investigation of some novel diorganotin(IV) complexes of tetraazamacrocyclic ligands

The tetradendate macrocyclic ligands, [H₂L-1 = 5,12-dioxa-7,14-dimethyl-1,4,8,11-tetraazacyclotetradeca-1,8-diene] and [H₂L-2 = 6,14-dioxa-8,16-dimethyl-1,5,9,13-tetraazacyclohexadeca-1,9-diene] have been prepared by the condensation reaction of 1,2-diaminoethane and 1,3-diaminopropane, respectively, with ethyl acetoacetate in methanol at room temperature. The diorganotin(IV) complexes of general formula [R₂Sn(L-1)/R₂Sn(L-2)] (R = Me, n-Bu and Ph) have been synthesized by template condensation reaction of 1,2-diaminoethane or 1,3-diaminopropane and ethyl acetoacetate with R₂SnCl₂ (R = Me or Ph) or n-Bu₂SnO in 2:2:1 molar ratio at ambient temperature (35 ± 2 °C) in methanol. The solid-state characterization of resulting complexes have been carried out by elemental analysis, IR, recently developed DART-mass, solid-state ¹³C NMR, ^119mSn Mössbauer spectroscopic studies. These studies suggest that in all of the studied complexes, the macrocyclic ligands act as tetradentate coordinating through four nitrogen atoms giving a skew-trapezoidal bipyramidal environment around tin center. Since, the studied diorganotin(IV) macrocyclic complexes are insoluble in common organic solvents, hence good crystals could not be grown for single crystal X-ray crystallographic studies. Thermal studies of all of the studied complexes have also been carried out in the temperature range 0-1000 °C using TG, DTG and DTA techniques. The end product of pyrolysis is SnO₂ confirmed by XRD analysis.     

Some new organotin(IV) schiff base adducts: Synthesis, spectroscopic characterization and thermal studies

Three new Schiff base adducts, [SnMe₂Cl₂(H₂cdnaphen)] (1), [SnPh₂Cl₂(H₂cdnaphen)₂].C₆H₆ (2) and [SnBu₂Cl₂(H₂cdnaphen)₂] (3) were synthesized by the reaction of SnR₂Cl₂ (R = Me, Bu and Ph) with a Schiff base ligand, Methyl 2-[2-(2-hydroxynaphthaldimino)ethylamino]-1-cyclopentene-1-dithiocarboxylate (H₂cdnaphen). The new products were characterized by elemental analysis, IR, ¹H NMR and ¹¹⁹Sn NMR spectroscopies. Spectroscopic data suggest that H₂cdnaphen exists predominately in keto-amine tautomeric form and in all complexes acts as a monodentate neutral ligand coordinating with the metal through oxygen atom, while the sulfur atom and imine nitrogen are not involved in coordination with the tin. Thermal decomposition of the complexes was studied through thermogravimetry and the thermodynamic activation parameters were determined by the Coats-Redfern method.