The synthesis,NMR (1H, 13C, 119Sn) and IR spectral studies of some di‐ and tri‐organotin(IV) sulfonates: X‐ray crystal structure of [(n‐C4H9)2Sn(OSO2C6H4CH3‐4)2·2H2O]

A number of alkyltin(IV) paratoluenesulfonates, R_nSn(OSO₂C₆H₄CH₃‐4)_4?n (n = 2, 3; R = C₂H₅, n‐C₃H₇, n‐C₄H₉), have been prepared and IR spectra and solution NMR (¹H, ¹³C, ¹¹⁹Sn) are reported for these compounds, including (n‐C₄H₉)₂Sn(OSO₂X)₂ (X = CH₃ and CF₃), the NMR spectra of which have not been reported previously. From the chemical shift δ(¹¹⁹Sn) and the coupling constants ¹J(¹³C, ¹¹⁹Sn) and ²J(¹H, ¹¹⁹Sn), the coordination of the tin atom and the geometry of its coordination sphere in solutions of these compounds is suggested. IR spectra of the compounds are very similar to that observed for the paratoluenesulfonate anion in its sodium salt. The studies indicate that diorganotin(IV) paratoluenesulfonates, and the previously reported compounds (n‐C₄H₉)₂Sn(OSO₂X)₂ (X = CH₃ and CF₃), contain bridging SO₃X groups that yield polymeric structures with hexacoordination around tin and contain non‐linear C? Sn? C bonds. In triorganotin(IV) sulfonates, pentacoordination for tin with a planar SnC₃ skeleton and bidentate bridging paratoluenesulfonate anionic groups are suggested by IR and NMR spectral studies. The X‐ray structure shows [(n‐C₄H₉)₂Sn(OSO₂C₆H₄CH₃‐4)₂·2H₂O] to be monomeric containing six‐coordinate tin and crystallizes from methanol–chloroform in monoclinic space group C2/c. The Sn? O (paratoluenesulfonate) bond distance (2.26(2) Å) is indicative of a relatively high degree of ionic character in the metal–anion bonds. Copyright © 2003 John Wiley & Sons, Ltd.     

Schiff base supported mononuclear organotin(IV) complexes: Syntheses,structures and fluorescence cell imaging

Three mononuclear organotin(IV) complexes supported by Schiff bases have been synthesized. The complexes [(C₆H₅)₂Sn(L)] ( 1 ), [(t‐Bu)₂Sn(L)] ( 2 ) and [(t‐Bu)₂Sn(L')] ( 3 ) (L, L' = deprotonated Schiff bases) were obtained in good yield by the reaction of Schiff bases H ₂ L or H ₂ L′ with corresponding diorganotin dichlorides respectively. All newly synthesized complexes were characterized by means of FT‐IR spectroscopy, elemental analysis and multinuclear (¹H, ¹³C and ¹¹⁹Sn) NMR spectroscopy. In addition, single crystal X‐ray diffraction analyses were employed to establish the solid state molecular structures of these complexes. The structures of 1 – 3 reveal that all complexes are mononuclear with a five‐coordinated tin(IV) centre in it. The absorption and emission properties of all complexes have been investigated. Moreover, cytotoxicity and fluorescence cell imaging studies of theses complexes have been performed.     

Synthesis,spectroscopic characterization (IR, 1H, 13C and 119Sn NMR,electrospray mass spectrometry) and toxicity of new organotin(IV) complexes with N,N′,O‐ and N,N′,S‐scorpionate ligands

New organotin(IV) derivatives containing the anionic ligands bis(3,5‐dimethylpyrazol‐1‐yl)dithioacetate [LCS₂]⁻ and bis(3,5‐dimethylpyrazol‐1‐yl)acetate [LCO₂]⁻ have been synthesized from reaction between (CH₃)₂SnCl₂ and lithium salts of the ligands. Mononuclear complexes of the type {[LCX₂](CH₃)₂SnCl} (X = S or O) have been obtained and fully characterized by elemental analyses and FT‐IR in the solid state and by NMR (¹H, ¹³C and ¹¹⁹Sn) spectroscopy, conductivity measurements and electrospray ionization mass spectrometry in solution. The acute toxicity of new organotin(IV) derivatives on rat was studied, comparing their effect with those of dimethyltin chloride (CH₃)₂SnCl₂. The comparison of LD₅₀ of organotin(IV) complexes and (CH₃)₂SnCl₂ administered intraperitoneally, as a single dose, evaluated in vivo on rats, showed that toxicity decreases as follows: (CH₃)₂SnCl₂ > LCO₂ > LCS₂. The effect of these organotin(IV) complexes on DNA was evaluated in vitro and in vivo on rats treated with different doses of these compounds (1/20 LD₅₀ and 1/100 LD₅₀). The lymphocyte DNA status was assessed by the comet assay, a rapid and sensitive single‐cell electrophoresis technique, used to detect primary DNA damage in individual cells. After 36 h from the start of treatment the two new organotin(IV) derivatives induced a significant rise in comet assay parameters, indicating an increasing presence of damaged DNA. Copyright © 2005 John Wiley & Sons, Ltd.     

Organotin(IV) Carboxylates of Substituted α‐Cinnamic Acid,RnSn(OCOC(R2)=CHR1)4 – n: Synthesis,Spectroscopic Characterization and Biological Evaluation

Di‐ and triorganotin(IV) carboxylates, R_nSn(OCOC(R²)=CHR¹)_4–n (n = 2 and 3; R = Me, Et, n‐Bu, Ph; R¹ = 3‐CH₃O‐4‐OHC₆H₃, R² = C₆H₅) were prepared by reacting the corresponding organotin(IV) chloride with the silver salt of the (E)‐3‐(4‐hydroxy‐3‐methoxyphenyl)‐2‐phenylpropenoic acid. The title compounds were investigated and characterized by elemental analysis, infrared (FT‐IR), multinuclear (¹H, ¹³C, ¹¹⁹Sn) NMR, and mass spectrometry, and possible structures were proposed. The complexes and ligand acid ( HL ) have been evaluated in vitro against various bacteria and fungi. The results noticed during the biocidal activity screenings proved their in vitro biological potential. They were also tested for cytotoxicity.     

Substituted Diorganotin(IV) O,O’-Alkylene Dithiophosphates: Synthesis and Spectral Aspects

Six new substituted diphenyltin(IV) O,O′-alkylene dithiophosphates, (C₆H₅)₂Sn(X)S(S) POGO [G = —CH₂C(CH₃)₂CH₂—, X = Cl (1), SCN (3), ClO₄ (5); G = —CH₂C (C₄H₉)(C₂H₅)CH₂—, X = Cl (2), SCN (4), ClO₄ (6)], were synthesized by the reaction of the corresponding ammonium salts of the O,O’-alkylene dithiophosphates with an appropriate organotin(IV) chloride. The compounds were characterized on the basis of elemental and spectral analyses (ESI mass spectrometry, IR, ¹H, ¹³C, ³¹P, and ¹¹⁹Sn NMR). The presence of a four-coordinated Sn atom and monodentate O,O’-alkylene dithiophosphate moiety in compounds 1–4 as well as bidentate O,O’-alkylene dithiophosphate unit in compounds 5,6 is established.     

Synthesis and Characterization of 1,3,2‐Bis (arylamino) phospholidine, 2‐oxide Derivatives: Crystal Structures of $\rm Cl(O)\overline{PN(p-Me-C_{6}H_{4})CH_{2}CH_{2}N}(p-Me-C_{6}H_{4})$ and $\rm ((CH_{2}C_{6}H_{5})(O)\overline{PN(p-Me-C_{6}H_{4})CH_{2}CH_{2}N}(p-Me-C_{6}H_{4})$

Using phosphoryl chloride as a substrate, a family of 1,3,2‐bis(arylamino) phospholidine, 2‐oxide of the general formula ; (X=Cl, 6a ; X=NMe₂, 1b ; X=N(CH₂C₆H₅)(CH₃), 2b ; X=NHC(O)C₆H₅, 3b ; X=4Me‐C₆H₄O, 4b ; X=C₆H₅O, 5b ; X=NHC₆H₁₁, 6b ; X=OC₄H₈N, 7b ; X=C₅H₁₀N, 8b ; X=NH₂, 9b ; X=F, 10b and Ar=4Me‐C₆H₄) was prepared and characterized by ¹H, ¹⁹F, ³¹P and ¹³C NMR and IR spectroscopy, and elemental analysis. A general and practical method for the synthesis of these compounds was selected. The structures of 6a and 2b were determined by single‐crystal X‐ray diffraction techniques. The low temperature NMR spectra of 2b revealed the restricted rotation of P‐N bond according to two independent molecules in crystalline lattice.     

Coordination behaviour of the 2‐(N,N‐dimethylaminomethyl)phenyl ligand towards the di‐t‐butylchlorotin(IV) moiety

{2‐(N,N‐Dimethylaminomethyl)phenyl}(di‐t‐butyl)tin(IV)chloride, {2‐[(CH₃)₂NCH₂]C₆H₄}Sn(t‐Bu)₂ Cl, has been prepared and characterized using NMR and crystallography. This is the first example of a triorganotin(IV) halide containing the 2‐[(CH₃)₂NCH₂]C₆H₄—group as a C,N‐chelating ligand with a weak intramolecular Sn—N interaction because of the steric hindrance of t‐butyl groups. The interatomic Sn—N distance is elongated to 2.904(14) Å and the central tin atom is distorted trigonal bipyramidal. Copyright © 2004 John Wiley & Sons, Ltd.     

C,N‐chelated triorganotin(IV) diesters of 4‐ketopimelic acid and their fungicidal activity

The set of four triorganotin(IV) diesters of 4‐ketopimelic acid containing {2‐[(CH₃)₂NCH₂]C₆H₄}‐ as a C,N‐chelating ligand was prepared. Their structures were studied by the help of IR, NMR and X‐ray crystallographic techniques in the case of {{2‐[(CH₃)₂NCH₂]C₆H₄}SnPh₂}₂[(OOCCH₂CH₂)₂C?]. All these compounds are monomeric both in solid state and solution with five‐coordinated tin atoms and medium strong intramolecular Sn? N connection. The antimycotical activity of these compound was studied and compared with the triorganotin(IV) derivatives of 4‐ketopimelic acid and antimycotical drugs in clinical use. Copyright © 2008 John Wiley & Sons, Ltd.     

Supramolecular organotin(IV) dithiocarboxylates as potential antimicrobial agents

A series of tri-, chlorodi-, and diorganotin(IV) derivatives of 4-(2-methoxyphenyl)piperazine-1-carbodithioate (L) {R?=?n-C₄H₉ (1), C₆H₁₁ (2), CH₃ (3) and C₆H₅ (4)}, (n-C₄H₉)₂SnClL (5) and R₂SnL₂ {R?=?n-C₄H₉ (6), C₂H₅ (7), CH₃ (8)} have been synthesized by refluxing organotin(IV) chlorides with the ligand-salt in the appropriate molar ratio. Elemental analysis, Raman, IR, multinuclear NMR (¹H, ¹³C and ¹¹⁹Sn), mass spectroscopic, and single-crystal X-ray crystallographic studies were undertaken to elucidate the structures of the new compounds both in solution and in the solid state. The X-ray diffraction work reveals supramolecular structures for 4 and 6, with distorted trigonal-bipyramidal and distorted octahedral geometries around Sn, respectively. The ligand and several of the new compounds are good antimicrobial agents.     

Conformational analysis of some 1R,4S‐2‐arylidene‐p‐menthan‐3‐ones by 1H NMR spectroscopy and molecular simulation

Based on ¹H NMR spectral analysis combined with molecular simulation, conformational states of the cyclohexanone ring were studied for some 1R,4S‐2‐(4‐X‐benzylidene)‐p‐menthan‐3‐ones (X = COOCH₃ or C₆H₅) in CDCl₃ and C₆D₆. The co‐existence of chair conformers with an axial orientation of both alkyl substituents and twist‐boat forms was established for the compounds studied at room temperature (22–23° C). The substituent X does not influence appreciably the ratio of these conformers, but the fraction of twist‐boat forms increases noticeably in benzene solutions as compared with CDCl₃ solutions. Rotameric states of the isopropyl fragment were also characterised for the compounds studied. Distinctions in conformational states for the 1R,4S‐2‐arylidene‐p‐menthan‐3‐ones and (?)‐menthone were revealed and are discussed. Copyright © 2002 John Wiley & Sons, Ltd.     

Two conformers in the solid state for a novel organotin(IV) complex of a phosphoramidate: Syntheses, spectroscopic study and crystal structures of several new organotin(IV) complexes of N-benzoylphosphoric triamides

Several novel organotin(IV) complexes with formula SnCl₂(CH₃)₂(X)₂, X = C₆H₅C(O)NHP(O)(NC₄H₈)₂ (1), C₆H₅C(O)NHP(O)(NC₅H₁₀)₂ (2), C₆H₅C(O)NHP(O)[N(CH₃)(C₆H₁₁)]₂ (3), C₆H₅C(O)NHP(O)[NH-C(CH₃)₃]₂ (4) were synthesized and characterized by ¹H, ¹³C, ³¹P NMR, IR spectroscopy and elemental analysis. The structures have been determined for each of the four compounds. Compound 1 exists in the form of two symmetrically independent molecules in the crystalline state due to differences in their similar torsion angles. In all of the four structures there are intramolecular -Sn-Cl?H-N- hydrogen bonds, in addition to weak C-H?O and C-H?Cl hydrogen bonds. Both ¹H and ¹³C NMR spectra show the coupling of ^119/117Sn nuclei with methyl proton and carbon atoms. The δ(³¹P) of these complexes are in upfields with respect to their corresponding reported ligands. The spectroscopic and structural properties of these complexes were compared with those corresponding ligands.     

Syntheses and Spectroscopic Study of Some New N‐4‐Fluorobenzoyl Phosphoric Triamides; Crystal Structures of 4‐F‐C6H4C(O)N(H)P(O)R2, R = NH‐C(CH3)3, NH‐CH2C6H5, N(CH3)(CH2C6H5)

Some new N‐4‐Fluorobenzoyl phosphoric triamides with formula 4‐F‐C₆H₄C(O)N(H)P(O)X₂, X = NH‐C(CH₃)₃ ( 1 ), NH‐CH₂‐CH=CH₂ ( 2 ), NH‐CH₂C₆H₅ ( 3 ), N(CH₃)(C₆H₅) ( 4 ), NH‐CH(CH₃)(C₆H₅) ( 5 ) were synthesized and characterized by ¹H, ¹³C, ³¹P NMR, IR and Mass spectroscopy and elemental analysis. The structures of compounds 1 , 3 and 4 were investigated by X‐ray crystallography. The P=O and C=O bonds in these compounds are anti. Compounds 1 and 3 form one dimensional polymeric chain produced by intra‐ and intermolecular ‐P=O···H‐N‐ hydrogen bonds. Compound 4 forms only a centrosymmetric dimer in the crystalline lattice via two equal ‐P=O···H‐N‐ hydrogen bonds. ¹H and ¹³C NMR spectra show two series of signals for the two amine groups in compound 1 . This is also observed for the two α‐methylbenzylamine groups in 5 due to the presence of chiral carbon atom in molecule. ¹³C NMR spectrum of compound 4 shows that ²J(P,C_aliphatic) coupling constant for CH₂ group is greater than for CH₃ in agreement with our previous study. Mass spectra of compounds 1 ‐ 3 (containing 4‐F‐C₆H₄C(O)N(H)P(O) moiety) indicate the fragments of amidophosphoric acid and 4‐F‐C₆H₄CN⁺ that formed in a pseudo McLafferty rearrangement pathway. Also, the fragments of aliphatic amines have high intensity in mass spectra.     

S,N‐Chelated organotin(IV) compounds containing 6‐phenylpyridazine‐3‐thiolate ligand—structural,antibacterial and antifungal study

A series of tri‐ and diorganotin(IV) compounds containing potentially chelating S,N‐ligand(s) (L^SN, where L^SN is 6‐phenylpyridazine‐3‐thiolate) were prepared and structurally characterized by multinuclear NMR spectroscopy. X‐ray diffraction techniques were used for determination of the structure of compounds containing one [(L^SN)Ph₂SnCl], two [(n‐Bu)₂Sn(L^SN)₂] and the combination of two L^SN and one L^CN [(L^CN)(n‐Bu)Sn(L^SN)₂] (where L^CN is {2‐[(CH₃)₂NCH₂]C₆H₄}‐) ligands. The coordination number of the tin atom varies from five to seven and is dependent on the number of chelating ligands present. The formation of the five‐membered azastanna heterocycle is favored over the formation of four‐membered azastannathia heterocycle in compounds containing both types of ligands. The di‐n‐butyl‐substituted compounds are the most efficient ones in inhibition of growth of yeasts, molds and G⁺ bacteria strains. Copyright © 2011 John Wiley & Sons, Ltd.     

Preparation and structures of [2‐(dimethylamino)phenyl]diorganotin(IV) acetates substituted with organophosphorus groups in the α‐position of the acetate ligand

Organotin(IV) carboxylates R₂L^NCSnOC(O)CH₂P(E)Ph₂, where L^NC is an N‐chelating 2‐(dimethylamino)phenyl group, and R/E = Ph/void (1a), Ph/O (1b), Ph/S (1c), Me/void (2a), Me/O (2b) and Me/S (2c), were synthesized, characterized by ¹H, ¹³C, ³¹P and ¹¹⁹Sn NMR, IR and MS spectra, and the solid‐state structures of 1b, 1c, 2b and 2c were determined by single‐crystal X‐ray diffraction. Spectral and structural data showed that the compounds are monomeric in CDCl₃ solution and the solid state, with the organophosphorus groups in the α‐position of the monodentate carboxylate ligands not interacting with the tin atom. Copyright © 2005 John Wiley & Sons, Ltd.     

Synthesis,characterization and antimicrobial activity of triorganotin(IV) derivatives of some bioactive Schiff base ligands

Triorganotin(IV) complexes of the type Me₃Sn[OC(R¹):CH(CH₃)C:NR²OH] and Ph₃Sn[OC(R′):CH(CH₃)C:NR″OH] (R′ = ─CH₃, ─C₆H₅; R″ = ─(CH₂)₂─, ─(CH₂)₃─) have been synthesized by the reactions of trimethyl/phenyltin(IV) chloride with the sodium salt of corresponding Schiff base ligands in unimolar ratio in refluxing tetrahydrofuran. All these compounds have been characterized using elemental analyses and their probable structures have been proposed on the basis of infrared, ¹H NMR, ¹³C NMR, ¹¹⁹Sn NMR and mass spectroscopic studies. In the trimethyltin(IV) derivatives the central tin atom is tetracoordinated, whereas in the analogous triphenyltin(IV)derivatives the central tin atom is pentacoordinated. All these ligands, metal precursors and corresponding triorganotin(IV) complexes have been screened for antimicrobial activities. A comparison of activities of the ligands and their corresponding triorganotin(IV) derivatives has been made. Attempts have also been made to relate the activity to the structure of these compounds.     

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.     

Synthetic and Mechanistic Aspects of the Immortal Ring‐Opening Polymerization of Lactide and Trimethylene Carbonate with New Homo‐ and Heteroleptic Tin(II)‐Phenolate Catalysts

Several new heteroleptic Sn^II complexes supported by amino‐ether phenolate ligands [Sn{LOⁿ}(Nu)] (LO¹=2‐[(1,4,7,10‐tetraoxa‐13‐azacyclopentadecan‐13‐yl)methyl]‐4,6‐di‐tert‐butylphenolate, Nu=NMe₂ ( 1 ), N(SiMe₃)₂ ( 3 ), OSiPh₃ ( 6 ); LO²=2,4‐di‐tert‐butyl‐6‐(morpholinomethyl)phenolate, Nu=N(SiMe₃)₂ ( 7 ), OSiPh₃ ( 8 )) and the homoleptic Sn{LO¹}₂ ( 2 ) have been synthesized. The alkoxy derivatives [Sn{LO¹}(OR)] (OR=OiPr ( 4 ), (S)‐OCH(CH₃)CO₂iPr ( 5 )), which were generated by alcoholysis of the parent amido precursor, were stable in solution but could not be isolated. [Sn{LO¹}]⁺[H₂N{B(C₆F₅)₃}₂]^? ( 9 ), a rare well‐defined, solvent‐free tin cation, was prepared in high yield. The X‐ray crystal structures of compounds 3 , 6 , and 8 were elucidated, and compounds 3 , 6 , 8 , and 9 were further characterized by ¹¹⁹Sn Mössbauer spectroscopy. In the presence of iPrOH, compounds 1 – 5 , 7 , and 9 catalyzed the well‐controlled, immortal ring‐opening polymerization (iROP) of L ‐lactide (L ‐LA) with high activities (ca. 150–550 mol_L?LA mol_Sn^?1 h^?1) for tin(II) complexes. The cationic compound 9 required a higher temperature (100 °C) than the neutral species (60 °C); monodisperse poly(L ‐LA)s were obtained in all cases. The activities of the heteroleptic pre‐catalysts 1 , 3 , and 7 were virtually independent of the nature of the ancillary ligand, and, most strikingly, the homoleptic complex 2 was equally competent as a pre‐catalyst. Polymerization of trimethylene carbonate (TMC) occurs much more slowly, and not at all in the presence of LA; therefore, the generation of PLA‐PTMC copolymers is only possible if TMC is polymerized first. Mechanistic studies based on ¹H and ¹¹⁹Sn{¹H} NMR spectroscopy showed that the addition of an excess of iPrOH to compound 3 yielded a mixture of compound 4 , compound [Sn(OiPr)₂]_n 10 , and free {LO¹}H in a dynamic temperature‐dependent and concentration‐dependent equilibrium. Upon further addition of L ‐LA, two active species were detected, [Sn{LO¹}(OPLLA)] ( 12 ) and [Sn(OPLLA)₂] ( 14 ), which were also in fast equilibrium. Based on assignment of the ¹¹⁹Sn{¹H} NMR spectrum, all of the species present in the ROP reaction were identified; starting from either the heteroleptic ( 1 , 3 , 7 ) or homoleptic ( 2 ) pre‐catalysts, both types of pre‐catalysts yielded the same active species. The catalytic inactivity of the siloxy derivative 6 confirmed that ROP catalysts of the type 1 – 5 could not operate according to an activated‐monomer mechanism. These mechanistic studies removed a number of ambiguities regarding the mechanism of the (i)ROPs of L ‐LA and TMC promoted by industrially relevant homoleptic or heteroleptic Sn^II species.     

Synthesis and characterization of dimeric organotin compounds {[(ArCH2)2 Sn(2‐quin)]2O}2 and crystal structure of {[(2‐ClC6 H4CH2)2Sn(2‐quin)]2O}2

Ten new dimeric organotin compounds {[(ArCH₂)₂ Sn(2‐quin)]₂O}₂ (Ar = Ph 1 , 2‐ClC₆H₄ 2 , 3‐ClC₆H₄ 3 , 4‐ClC₆H₄ 4 , 2‐FC₆H₄ 5 , 3‐FC₆H₄ 6 , 4‐FC₆H₄ 7 , 4‐BrC₆H₄ 8 , 4‐CNC₆H₄ 9 , 2,4‐Cl₂C₆H₃ 10 ) have been synthesized by dealkylation reactions of 2‐quinH with [(ArCH₂)₃Sn]₂O, and their structures have been characterized by elemental analysis, IR and NMR (¹}H, ¹³C, ¹¹⁹Sn) spectroscopies. The structures of {[(2‐ClC₆H₄CH₂)₂Sn(2‐quin)]₂O}₂ 2 have been determined by X‐ray diffraction. Studies show that compound 2 has a tetranuclear, centrosymmetric dimeric structure, with the endo‐cyclic tin atom five‐coordinated and the exo‐cyclic tin atom six coordinated. Studies also show that the nitrogen atoms of the 2‐quin ligand are coordinating to the tin atom for all the ten compounds. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:152–159, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20194     

Synthesis and characterization of di‐n‐butyltin(IV) complexes with 4′/2′‐nitrobiphenyl‐2‐carboxylic acids: X‐ray crystal structures of [{(n‐C4H9)2Sn(OCOC12H8NO2−4′)}2O]2 and (n‐C4H9)2Sn{OCOC12H8NO2−4′}2

Reactions of di‐n‐butyltin(IV) oxide with 4′/2′‐nitrobiphenyl‐2‐carboxylic acids in 1 : 1 and 1 : 2 stoichiometry yield complexes [{(n‐C₄H₉)₂Sn(OCOC₁₂H₈NO₂?4′/2′)}₂O]₂ ( 1 and 2 ) and (n‐C₄H₉)₂Sn(OCOC₁₂H₈NO₂?4′/2′)₂ ( 3 and 4 ) respectively. These compounds were characterized by elemental analysis, IR and NMR (¹H, ¹³C and ¹¹⁹Sn) spectroscopy. The IR spectra of these compounds indicate the presence of anisobidentate carboxylate groups and non‐linear C? Sn? C bonds. From the chemical shifts δ (¹¹⁹Sn) and the coupling constants ¹J(¹³C, ¹¹⁹Sn), the coordination number of the tin atom and the geometry of its coordination sphere have been suggested. [{(n‐C₄H₉)₂Sn(OCOC₁₂H₈NO₂?4′)}₂O]₂ ( 1 ) exhibits a dimeric structure containing distannoxane units with two types of tin atom with essentially identical geometry. To a first approximation, the tin atoms appear to be pentacoordinated with distorted trigonal bipyramidal geometry. However, each type of tin atom is further subjected to a sixth weaker interaction and may be described as having a capped trigonal bipyramidal structure. The diffraction study of the complex (n‐C₄H₉)₂Sn(OCOC₁₂H₈NO₂?4′)₂ ( 3 ) shows a six–coordinate tin in a distorted octahedral frame containing bidentate asymmetric chelating carboxylate groups, with the n‐Bu groups trans to each other. The n‐Bu? Sn? n‐Bu angle is 152.8° and the Sn? O distances are 2.108(4) and 2.493(5) Å. The oxygen atom of the nitro group of the ligand does not participate in bonding to the tin atom in 1 and 3 . Crystals of 1 are triclinic with space group P1 and of that of 3 have orthorhombic space group Pnna. Copyright © 2003 John Wiley & Sons, Ltd.     

Synthesis,structural characterization and in vitro cytotoxic activity of novel polymeric triorganotin(IV) complexes of urocanic acid

Two novel triorganotin carboxylate complexes of the biologically active urocanic acid have been synthesized and characterized. Elemental analysis, melting point, spectroscopic techniques – IR, ¹H, ¹³C and ¹¹⁹Sn NMR – mass spectrometry and X‐ray diffraction studies have been used for structural characterization. Crystal structures of the tin(IV) derivatives show that urocanic acid acts as a bridging bidentate ligand through its imidazole nitrogen atom and its carboxylic group, producing a polymeric one‐dimensional chain. The molecular structures of the complexes, catena‐poly‐tri(n‐butyl)tin(IV) 3‐(3H‐imidazol‐4‐yl)prop‐2‐enoate (1) and catena‐poly‐triphenyltin(IV) 3‐(3H‐imidazol‐4‐yl)prop‐2‐enoate (2), present a distorted trigonal–bipyramidal configuration. This is further confirmed by ¹¹⁹Sn NMR in the solid state. The tin(IV) derivatives form double‐stranded ribbons via N―H^…O―H bonds. Nevertheless, the compounds are essentially monomeric in solution, with a tetrahedral configuration as observed by ¹¹⁹Sn NMR in solution. The cytotoxic activity of the titled compounds has been tested against six human cell lines and the corresponding IC₅₀ values are reported. Both tin(IV) compounds have a high to very high in vitro cytotoxic activity against the tumor cell lines K562, HCT‐15 and MCF‐7. Compound 1 is 86 times more active than cisplatin in the HTC‐15 cell line. Copyright © 2012 John Wiley & Sons, Ltd.