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).     

Preparation and spectroscopic studies of diorganotin oxycarbonates

The synthesis, ^119mSn Mössbauer and infrared spectra of a series of diorganotin oxycarbonates of the type, (R₂Sn)₂OCO₃·nH₂O, where R = Me, Et, Ph, n = 0; R = Pr, Bu, Oct, n = 1, are reported.Structures are proposed for these compounds in the solid state, on the basis of their spectroscopic data.     

Synthesis, 119Sn Mössbauer spectroscopic studies and X-ray crystal structure determination of new seven-coordinate diorganotin(IV) complexes with S,N,N,N,S-pentadentate Schiff bases derived from 2,6-diacetylpyridine of S-methyl- and S-benzyldithiocarbazates

The reactions of the ligands 2,6-diacetylpyridine bis(S-methyldithiocarbazate)] (H₂dapmdtc) and 2,6-diacetylpyridine bis(S-benzyldithiocarbazate)] (H₂dapbdtc) with R_4-m SnCl _m (R = Me, ⁿ Bu, Ph; and m = 2) led to the formation of six seven-coordinate diorganotin(IV) complexes, which were studied by microanalysis, i.r., n.m.r (¹H, ¹¹⁹Sn) and Mössbauer spectroscopies. The X-ray structures determination of complexes [Me₂Sn(dapmdtc)], [Me₂Sn(dapbdtc)] and [Ph₂Sn(dapbdtc)] revealed the presence of neutral seven-coordinated complexes. The structures consist of monomeric units in which the Sn(IV) atom exhibits distorted pentagonal bipyramidal (PBP) geometry, with the S,N,N,N,S-donor systems of the ligands lying in the equatorial plane and organic groups in the apical positions. A correlation between Mössbauer and X-ray data based on the point-charge model is discussed.     

Synthesis and characterization of diorganotin(IV) complexes of tetradentate Schiff bases: crystal structure of n-Bu2Sn(Vanophen)

Diorganotin(IV) complexes of the general formula R₂SnL (R=Ph, n-Bu and Me) have been prepared from diorganotin(IV) dichlorides (R₂SnCl₂) and tetradentate Schiff bases (H₂L) containing N₂O₂ donor atoms in the presence of triethylamine in benzene. The Schiff bases, H₂L, were derived from salicylaldehyde, 3-methoxysalicylaldehyde (o-vanillin), 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone and diamines such as o-phenylenediamine and 1,3-propylenediamine. The complexes were characterized by IR, NMR (¹H, ¹³C, ¹¹⁹Sn) and elemental analysis. The structure of the complex, n-Bu₂Sn(Vanophen), was determined using single crystal X-ray diffraction. The tin atom has a distorted octahedral coordination, with the Vanophen ligand occupying the four equatorial positions and the n-butyl groups in the trans axial positions. Six-coordinated distorted octahedral structures have been proposed for all diorganotin(IV) complexes studied here, as they possess similar spectroscopic data.     

Diorganotin(IV) and triorganotin(IV) derivatives of diphenic acid

The diorganotin(IV) and triorganotin(IV) derivatives R₂SnA (R = Me, n-Pr, n-Bu, n-Oct) and (R₃Sn)₂A [R = Me, Ph, cyclohexyl (Cyh); A = an anion of diphenic acid] have been prepared and characterized by elemental analysis, IR, ¹H and ¹³C NMR spectroscopies. Tetrahedral tin forms a part of a diphenate cyclic ring in the diorganotin complexes with unidentate carboxylates, which have further been used for the synthesis of cyclic acid anhydrides. The soluble dinuclear triorganotin complexes (Me, Ph) possess symmetrically bonded carboxylates while the less soluble compound (Cyh₃Sn)₂A has two asymmetrically bonded carboxylates. All have a trigonal bipyramidal structure with R₃Sn units remote from each other.     

Mössbauer and infrared spectroscopic studies of some organotin(IV) schiff base complexes

Several organotin(IV) complexes with quadri- and terdentate anionic Schiff base ligands have been investigated in the solid state using ¹¹⁹Sn Mössbauer and IR spectroscopies, Mössbauer parameters derived from both zero-field and magnetically perturbed spectra suggest that the R₂Sn(Salen)(R = Me, Et, Ph) and Me₂Sn(Saldap-2OH) complexes have similarly distorted trans-octahedral structures. However, in Ph₂Sn(HSaldap-2-O) the ligand appears to be only terdentate, leading to a penta-coordinate structure similar to those of the R₂Sn(Sal-N-2-OC₆H₄) derivatives (R = Me, Ph). For Ph₃Sn(Sal-N-2-OC₆H₄) the asymmetry parameter of the electric field gradient is close to unity, confirming a mer-octahedral configuration for this complex.     

DNA Binding Studies and Evaluation of Electrochemical Parameters of New Tri-and Di-Organotin(IV) Complexes of 4-(1H-Indol-3-yl)butanoic Acid

New triorganotin(IV) [R₃SnL where R = Me (1), Bu (2), Ph (3)] and diorganotin(IV) [R₂SnL₂, where R = Me (4), Bu (5), Ph (6)] derivatives of 4-(1H-indol-3-yl)butanoic acid (HL) were prepared and characterized by FT-IR and ¹H and ¹³C NMR spectroscopy. Interaction between DNA and selected compounds was studied by UV-Vis spectroscopy and viscometry. The binding constants calculated on the basis of the accumulated data reveal the following order of binding strength: compound 2 > 1 > 5 > 4. Electrochemical parameters such as diffusion coefficient and charge transfer coefficient are evaluated with cyclic voltammetry. The results demonstrate that diorganotin(IV) complexes are characterized by higher diffusion coefficient than triorganotin(IV) analogues. In case of triorganotin(IV) complexes, the lower coordination number allows a solvent to interact with Sn(IV) center and hence decreases the rate of diffusion.

     

Diorganotin(IV) complexes of 2,5‐dithiobiurea (H2dtbu). The crystal structures of Me2Sn(dtbu) and Ph2Sn(dtbu)

The diorganotin(IV) complexes, R₂Sn(dtbu) (R = Me 1 , n‐Bu 2 , Ph 3 , PhCH₂ 4 ; H₂dtbu = 2,5‐dithiobiurea), have been synthesized and characterized by IR, ¹H, and ¹¹⁹Sn NMR spectroscopy. The structures of 1 and 3 have been determined by X‐ray crystallography. Crystal structures show that both complexes 1 and 3 consist of molecules in which the bideprotonated ligand is N,S,S‐bonded, and the tin atom exhibits distorted pentacoordination with small differences between the methyl and phenyl derivatives in bond distances and bond angles. The unusual coordination mode of the dtbu²⁻ anion creates four‐ and five‐membered chelate rings. Moreover, the packing of complexes 1 and 3 are stabilized by the hydrogen bonding. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:93–98, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20173     

Multinuclear (Sn/Pd) complexes with disodium 2,2′-(dithiocarboxyazanediyl)diacetate hydrate; Synthesis,characterization and biological activities

Bimetallic chlorodi-/triorganotin(IV) derivatives of general formulas R₂(H₂O)SnLCSSSn(Cl)R₂ (R=Me: 1; Ph: 2) and R₃Sn(Na)LCSSSnR₃·H₂O (R=Bu: 3; Ph: 4) were prepared by reaction of iminodiacetic acid disodium salt hydrate (Na₂LH) with CS₂ and R₂SnCl₂/R₃SnCl in methanol. The reaction between Na₂LH, CS₂, and PdCl₂ produced [Na₂LCSS]₂Pd·2H₂O (5) which was treated with R₃SnCl to synthesize the heterobimetallic derivatives [R₃Sn(Na)LCSS]₂Pd·2H₂O (R=Me: 6; Ph: 7). The complexes were characterized by microanalysis, spectroscopic, and thermogravimetric analyses. Elemental analysis data, mass fragmentation, and thermal degradation patterns supported the molecular composition of the complexes. FT-IR data indicated monodentate binding of carboxylate while a chelating coordination mode of the dithiocarboxylate was verified in the solid state. A five-coordinate tin(IV) was demonstrated in the solid state. In solution, a tetrahedral/trigonal bipyramidal configuration around Sn(IV) and a square planar geometry of Pd(II) was indicated by multinuclear NMR (¹H and ¹³C) and UV-visible studies. The Pd(II) derivatives showed interaction with salmon sperm-DNA and caused an inhibition of alkaline phosphatase (ALPs). The antibacterial/antifungal potential of the coordination products varied with the nature of incorporated metal and a substitution pattern at tin(IV); the palladium metallation decreased the antimicrobial activities. The triorganotin(IV) products exhibited more powerful action against bacteria/fungi as compared to their diorganotin(IV) counterparts. The complexes displayed sufficiently lower hemolytic effects in vitro as compared to triton X-100 and slightly higher than PBS.     

Structure and conformational motion of seven-coordinate diorganotin(IV) complexes derived from salen and salan type ligands

Reaction of R₂SnCl₂ (R = Me, nBu, Ph) and the potassium salts of salenN₃H₃ (N,N′-bis(salicylidene)diethylenetriamine) and saleanN₃H₅ (N,N′-bis(o-hydroxybenzyl)diethylenetriamine) provided diorganotin(IV) complexes of the composition [Me₂Sn(salenN₃H)]·solvate (solvate = 2.5H₂O, MeOH or DMSO), [nBu₂Sn(salenN₃H)]·H₂O, [Ph₂Sn(salenN₃H)]·2EtOH and [Me₂Sn(saleanN₃H₃)]·2.5H₂O. In all compounds the tin atoms are seven-coordinate and have pentagonal-bipyramidal coordination environments, in which the organic substituents attached to the tin atoms occupy the axial positions. This occurs both in solution and the solid state; however, in solution the molecules are involved in conformational equilibria that require the presence of intermediates, in which the N → Sn bonds are dissociated. Although the [saleanN₃H₃]²⁻ ligand is more flexible and basic, a very similar complexing behavior to that of [salenN₃H]²⁻ has been found, and there is evidence that it is even a weaker ligand. Both ligands show the tendency to adopt a curved conformation within the complex, thus indicating that the dynamic process resembles the flapping of butterfly wings. However, the folding is reduced with increasing steric bulk of the organic substitutents attached to the tin atoms. The six-membered heterocyclic rings in the [R₂Sn(salenN₃H)] derivatives have envelope conformation, while those in [Me₂Sn(saleanN₃H₃)] have distorted boat-conformation. Thus, small changes in the hybridization and basicity of the nitrogen atoms cause significant differences of the stability and the dynamic behavior of the resulting molecules.     

Structural and conformational analysis of neutral dinuclear diorganotin(IV) complexes derived from hexadentate Schiff base ligands

The synthesis of three hexadentate Schiff base ligands has been carried out, which contain two sets of ONO donor atoms. These were reacted with diorganotin(IV) dichloride derivatives (R = Me, nBu, Ph) to prepare seven dinuclear diorganotin(IV) complexes in moderate yields. Aside from IR and NMR (¹H, ¹³C, ¹¹⁹Sn) spectroscopic studies, mass spectrometry and elemental analysis, four tin complexes were characterized by X-ray diffraction analysis. The spectroscopic analyses showed that in solution the tin atoms have five-coordinate environments with a distorted trigonal bipyramidal geometry. Each tin atom is coordinated to the nitrogen atom and forms covalent bonds with two oxygen atoms and two carbon atoms. Due to the presence of a methylene group as bridge between the two ONO chelates, the overall molecular structures can have cis or trans conformation, having either mirror or C₂-symmetry. While in solution a fast equilibrium can be supposed, in the solid state different intermediate conformations have been detected. Furthermore, for the dialkyltin derivatives Sn?O intermolecular interactions were found allowing for a dimeric or crinkled polymeric organization, whereas for the diphenyltin derivatives no such interactions were observed.     

Synthesis,characterization, and in vitro antimicrobial activities of organotin(IV) complexes of Schiff bases with ONO‐type donor atoms

A new series of diorganotin complexes of the type R₂SnL (L¹: N‐(2‐hydroxy‐5‐chlorophenyl)‐ 3‐ethoxysalicylideneimine, R = Me, (Me₂SnL¹), R = n‐Bu, (n‐Bu₂SnL¹), R = Ph, (Ph₂SnL¹), L²: N‐(2‐hydroxy‐4‐nitro‐5‐chlorophenyl)‐3‐ethoxysalicylideneimine, R = Ph, Ph₂SnL², L³: N‐(2‐hydroxy‐4‐nitrophenyl)‐3‐methoxysalicylideneimine, R = Me, (Me₂SnL³), R = n‐Bu, (n‐Bu₂SnL³), L⁴: N‐(2‐hydroxy‐4‐nitrophenyl)‐3‐ethoxysalicylideneimine, R = Me, (Me₂SnL⁴), R = n‐Bu, (n‐Bu₂SnL⁴)) were synthesized and characterized by elemental analysis, infrared (IR), ¹H, and ¹³C NMR mass spectroscopic techniques, and electrochemical measurements. Ph₂SnL¹ and Ph₂SnL² were also characterized by X‐ray diffraction analysis and were found to show a fivefold C₂NO₂ coordination geometry nearly halfway between a trigonal bipyramidal and distorted square pyramidal arrangement. The C Sn C angles in the complexes were calculated using Lockhart's equations with the ¹J(^117/119Sn‐¹³C) and ²J(^117/119Sn‐¹H) values from the ¹H NMR and ¹³C NMR spectra. Biocidal activity tests against several micro‐organisms and some fungi indicate that all the complexes are mildly active against Gram (+) bacteria and the fungi, A. niger and inactive against Gram (−) bacteria. © 2010 Wiley Periodicals, Inc. Heteroatom Chem 21:373–385, 2010; View this article online at wileyonlinelibrary.com . DOI 10.1002/hc.20628     

Organometallic complexes with biological molecules. I. Diorganotin(IV)chloro protoporphyrin IX complexes: Solid-state and solution-phase characterization

Protoporphyrin IX (H₄PPIX) complexes of diorganotin(IV)chloro moieties with formula (R₂SnCl)₂H₂PPIX (R?Me, Bu and Ph) have been obtained and their solid-state and solution-phase configurations have been studied through spectroscopic investigations. Coordination of the side-chain carboxylates of H₄PPIX to R₂Sn(IV)Cl moieties, with bridging carboxylate (COO^?) has been inferred by comparison of the free and coordinated H₄PPIX IR spectra, while the occurrence of a five-coordinated tin(IV) atom in a cis-R₂ trigonal bipyramidal structure has been deduced, for all of the synthesized complexes, by rationalization of the nuclear quadrupole splitting parameters, according to the point-charge model formalism. Fanally, the solution-phase spectral features of (R₂SnCl)₂^?H₂PPIX are in agreement with the monomeric character of the protoporphyrin IX, under the experimental conditions used.     

Organotin(IV) derivatives as biocides: An investigation of structure by IR, solution NMR, electron impact MS and assessment of structure correlation with biocidal activity

A brief account is given of the synthesis, structural chemistry and the antibacterial, antifungal and cytotoxic effects of organotin complexes of 2-[(2,4-dichloroanilinocarbonyl)]benzoic acid. The unimolar and bimolar substitution products have been characterized by elemental analysis and spectral studies, including IR, ¹H NMR, ¹³C NMR, ¹¹⁹Sn NMR, and mass spectra. The data support the binding of the oxygen atom to the tin atom in [R₂Sn(OOCR’)₂] and [R₃Sn(OOCR’)] (R = Me, Bu, and Ph, R’ = 2-[(2,4-dichloroanilinocarbonyl)]benzoic acid). Based on these studies, with a coordination number of four, a distorted tetrahedral geometry has been proposed for the resulting derivatives in solution. The free ligand (R’/COOH) and its respective tin complexes were tested in vitro against a number of microorganisms to assess their biocidal properties and to correlate them with the structures of the derivatives.     

Synthesis and characterization of pentagonal bipyramidal organotin(IV) complexes of 2,6-diacetylpyridine Schiff bases of S-alkyl- and aryldithiocarbazates

New organotin(IV) complexes with empirical formula Sn(SNNNS)R₂, where SNNNS is the dianionic form of 2,6-diacetylpyridine Schiff bases of S-methyldithiocarbazate (H₂dapsme) or S-benzyldithiocarbazate (H₂dapsbz) and R = Ph or Me, have been prepared and characterized by IR, UV-Vis, NMR and Mössbauer spectroscopic techniques and conductance measurements. The molecular structures of the Sn(dapsme)R₂ (R = Ph and Me) have been determined by single crystal X-ray diffraction techniques. Both complexes have a distorted pentagonal-bipyramidal geometry in which the tin is coordinated by a dinegatively charged pentadentate chelating agent via pyridine nitrogen, two azomethine nitrogens, and two thiolate sulfurs. The five donors (N₃S₂) provided by the Schiff base occupy the equatorial plane close to a pentagonal planar array while the carbanion ligands occupy axial sites.     

Synthesis,structural characterization and cytotoxic activity of diorganotin(IV) complexes of N‐(5‐halosalicylidene)‐α‐amino acid

Fourteen new diorganotin(IV) complexes of N‐(5‐halosalicylidene)‐α‐amino acid, R′₂Sn(5‐X‐2‐OC₆H₃CH?NCHRCOO) (where X = Cl, Br; R = H, Me, i‐Pr; R′ = n‐Bu, Ph, Cy), were synthesized by the reactions of diorganotin halides with potassium salt of N‐(5‐halosalicylidene)‐α‐amino acid and characterized by elemental analysis, IR and NMR (¹H, ¹³C and ¹¹⁹Sn) spectra. The crystal structures of Bu₂Sn(5‐Cl‐2‐OC₆H₃CH?NCH(i‐Pr)COO) and Ph₂Sn(5‐Br‐2‐OC₆H₃CH?NCH(i‐Pr)COO) were determined by X‐ray single‐crystal diffraction and showed that the tin atoms are in a distorted trigonal bipyramidal geometry and form five‐ and six‐membered chelate rings with the tridentate ligand. Bioassay results of a few compounds indicated that the compounds have strong cytotoxic activity against three human tumour cell lines, i.e. HeLa, CoLo205 and MCF‐7, and the activity decreased in the order Cy>n‐Bu>Ph for the R′ group bound to tin. Copyright © 2005 John Wiley & Sons, Ltd.     

Synthese und Struktur C,N‐difunktionalisierter Sulfinimidamide

Synthesis and Structure of C,N‐difunctionalized Sulfinimideamides Sulfurdiimides RN=S=NR ( 1 a , b ) react in diethyl ether with two equivalents of lithiummethyl to give dimeric C,N‐dilithiummethylenesulfinimideamide ether adducts {Li₂[H₂C–S(NR)₂ · Et₂O]}₂ ( 2 a , b ) ( a : R = ^tBu, b : R = SiMe₃). Metathesis of 2 b with four equivalents of Me₃SiCl, Me₃SnCl or Ph₃SnCl yields the corresponding C,N‐bis‐substituted sulfinimideamides R₃EH₂C–S[N(SiMe₃)₂]NER₃ ( 3 – 5 ) ( 3 : R = Me, E = Sn; 4 : R = Ph, E = Sn; 5 : R = Me, E = Si). The crystal structures of 2 a and 2 b were determined by X‐ray structure analysis. Both compounds form centrosymmetric cage structures consisting of two distorted face sharing cubes ( 2 a : space group P1 (No. 2); Z = 2 (4 · 0,5); 2 b : space group C2/c (No. 15), Z = 4).     

New di- and triorganotin(IV) derivatives of tyrosinylphenylalanine as models for metal-protein interactions: Synthesis and structural characterization. Crystal structure of Me2Sn(Tyr-Phe) · MeOH

New di- and triorganotin(IV) derivatives of tyrosinylphenylalanine (H₂Tyr-Phe) with general formulae R₂Sn(Tyr-Phe) where R = Me,n-Bu, n-Oct and Ph, and R₃^′Sn(HTyr-Phe) where R^′ = Me and Ph have been synthesized. The bonding and coordination behaviour in these derivatives are discussed on the basis of FT-IR, multinuclear ¹H, ¹³C and ¹¹⁹Sn NMR and ¹¹⁹Sn Mössbauer spectroscopic studies. These investigations suggest that dipeptide in R₂Sn(Tyr-Phe) acts as dianionic tridentate coordinating through −C(O)O⁻, -NH₂ and (-CO)N⁻_peptide groups while in case of R^′₃Sn(HTyr-Phe) the ligand acts as monoanionic bidentate coordinating through -C(O)O⁻ and -NH₂, and the polyhedron around tin in R₂Sn(Tyr-Phe) and R^′₃Sn(HTyr-Phe) is a distorted trigonal-bipyramidal. It is further confirmed by the single crystal X-ray structure of Me₂Sn(Tyr-Phe) · MeOH which shows two methyl groups and peptide nitrogen (N⁻_peptide) in the equatorial positions, while the two axial positions are occupied by the carboxylic oxygen (O⁻_carboxyl) and the amino nitrogen (N_amino) atom from the same ligand molecule. One methanol molecule is also present in the asymmetric unit.     

Synthesis,Structure–Activity Relationship of Some New Triorganotin(IV) Derivatives of Dipeptides as Anti-Inflammatory Agents

Abstract

New triorganotin(IV) derivatives of dipeptides with general formulae, R₃Sn(HL), where R = Me and Ph, and HL is the monoanion of histidinylalanine and histidinylleucine, have been synthesized and characterized on the basis of infrared (IR), multinuclear NMR (¹H, ¹³C, and ¹¹⁹Sn), and ¹¹⁹Sn Mössbauer spectroscopic studies. These derivatives exhibit distorted trigonal-bipyramidal geometry around tin in which dipeptide anion acts as bidentate ligand coordinating through carboxyl oxygen and amino nitrogen. Ph₃Sn(HHis-Ala),

Ph₃Sn(HHis-Leu), and previously reported Ph₂Sn(His-Ala), Me₂Sn(His-Ala), n-Oct₂Sn(His-Ala), Me₂Sn(His-Leu), n-Oct₂Sn(His-Leu), Ph₃Sn(HTyr-Phe), Ph₂Sn(Tyr-Phe), Bu₂Sn-(Tyr-Phe), and n-Oct₂Sn(Tyr-Phe) along with standard drugs, viz. phenyl butazone and indomethacin were screened for in vivo anti-inflammatory activity and acute toxicity (LD₅₀). Diorganotin(IV) derivatives are more active than triorganotin(IV) derivatives. Me₂Sn(His-Leu) shows the highest activity.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Synthesis,spectral and antimicrobial studies of diorganotin(IV)3(2′‐hydroxyphenyl)‐5‐(4‐substituted phenyl) pyrazolinates

Diorganotin(IV) dipyrazolinates of the type R₂Sn(C₁₅H₁₂N₂OX)₂ [where C₁₅H₁₂N₂OX = 3(2′‐Hydroxyphenyl)‐5(4‐X‐phenyl)pyrazoline {where X = H ( a ); CH₃ ( b ); OCH₃ ( c ); Cl ( d ) and R = Me, Prⁿ and Ph}] have been synthesized by the reaction of R₂SnCl₂ with sodium salt of pyrazolines in 1:2 molar ratio, in anhydrous benzene. These newly synthesized derivatives have been characterized by elemental analysis (C, H, N, Cl and Sn), molecular weight measurement as well as spectral [IR and multinuclear NMR (¹H, ¹³C and ¹¹⁹Sn)] studies. The bidentate behaviour of the pyrazoline ligands was confirmed by IR, ¹H and ¹³C NMR spectral data. A distorted trans‐octahedral structure around tin(IV) atom for R₂Sn(C₁₅H₁₂N₂OX)₂ has been suggested. The free pyrazoline and diorganotin(IV) dipyrazolinates have also been screened for their antibacterial and antifungal activities. Some diorganotin(IV) dipyrazolinates exhibit higher antibacterial and antifungal effect than free ligand and some of the antibiotics. Copyright © 2006 John Wiley & Sons, Ltd.