Highly efficient water promoted allylation and propargylation of arylepoxides via rearrangement-carbonyl addition

A simple and highly efficient one-pot procedure for allylation and propargylation of arylepoxides has been developed. A combination of SnCl₂ and catalytic Pd(0) or Pd(II) promotes the reaction of organic halides and epoxides in DMSO with controlled water addition, leading to the regioselective formation of the corresponding homoallyl and homopropargyl alcohols in good yields.     

Iodine-catalyzed allylation and propargylation of indoles with allylic and propargylic acetates

A mild and efficient allylation/propargylation of indoles has been developed with high regioselectivity and excellent yields. In the presence of catalytic molecular iodine, various indoles could react with allylic/propargylic acetates smoothly at room temperature to exclusively provide C-3 alkylated products.     

Review: structural diversity in organotin(IV) dithiocarboxylates and carboxylates

Organotin(IV) complexes are known for their outstanding structural diversity and applications. Organotin(IV) carboxylates and dithiocarboxylates form an important class of organotin(IV) compounds. The structural diversity of these compounds emanates from several features including flexibility in coordination geometries, coordination numbers, and versatility of the ligands to engage in different modes of chelation from monodentate to bidentate. Triorganotin(IV) complexes with various ligands mostly demonstrate tetrahedral or trigonal bipyramidal symmetry with some distortions, while diorganotin(IV) and chlorodiorganotin(IV) complexes have variation of geometries and coordination numbers. Some monoorganotin(IV) complexes have also been reported with pentagonal bipyramidal geometries.     

Structural properties and antibacterial potency of new supramolecular organotin(IV) dithiocarboxylates

A series of new organotin(IV) derivatives; Me₃SnL (1), Bu₃SnL (2), Ph₃SnL (3), Me₂SnClL (4), Bu₂SnClL (5), Ph₂SnClL (6), Et₂SnClL (7) and Et₂SnL₂ (8) where L = N-(2,3-dimethylphenyl)piperazine-1-carbodithioate have been synthesized and characterized by various analytical techniques. Among these techniques, ¹H and ¹³C NMR were carried out to asses solution structures whereas the solid state structures were confirmed by FT-IR and X-ray single crystal analysis (3, 5 and 8). Crystal structure of complex (3) and (5) showed distorted trigonal bipyramidal geometry and square pyramidal geometry, respectively. The inclination of the structure 5 towards square-pyramidal may be due to the presence of the Sn-Cl?HN-piperazine hydrogen bonds between the adjacent molecules. A supramolecular structure is shown by compound (8), with central tin atom exists in a distorted octahedral geometry. The antibacterial results indicated the profound activity of the compounds against various strains of bacteria. In addition to this, the triorganotin(IV) derivatives were found more active than diorganotin(IV) compounds.     

Investigation on coordination modes of organotin(IV) complexes with 6-thiopurine and related ligands

The organotin(IV) complexes R₂Sn(tpu)₂ · L [L = 2MeOH, R = Me (1); L = 0: R = n-Bu (2), Ph (3), PhCH₂ (4)], R₃Sn(Hthpu) [R = Me (5), n-Bu (6), Ph (7), PhCH₂ (8)] and (R₂SnCl)₂ (dtpu) · L [L = H₂O, R = Me (9); L = 0: R = n-Bu (10), Ph (11), PhCH₂ (12)] have been synthesized, where tpu, Hthpu and dtpu are the anions of 6-thiopurine (Htpu), 2-thio-6-hydroxypurine (H₂thpu) and 2,6-dithiopurine (H₂dtpu), respectively. All the complexes 1-12 have been characterized by elemental, IR, ¹H, ¹³C and ¹¹⁹Sn NMR spectra analyses. And complexes 1, 2, 7 and 9 have also been determined by X-ray crystallography, complexes 1 and 2 are both six-coordinated with R₂Sn coordinated to the thiol/thione S and heterocyclic N atoms but the coordination modes differed. As for complex 7 and 9, the geometries of Sn atoms are distorted trigonal bipyramidal. Moreover, the packing of complexes 1, 2, 7 and 9 are stabilized by the hydrogen bonding and weak interactions.     

Antimicrobial studies of newly synthesized organotin(IV) complexes of dihydrobis(2-mercaptothiazolinyl)borate

Four organotin(IV) complexes of dihydrobis(2-mercaptothiazolinyl)borate were synthesized and characterized by elemental analysis and spectroscopic techniques (IR, ¹H-NMR, ¹³C-NMR, ¹¹B-NMR, and ¹¹⁹Sn-NMR). All the compounds were screened against bacterial, fungal, and cyanobacterial strains. Among the complexes, triorganotin(IV) complexes show better inhibition growth as compared to diorganotin(IV) complexes.     

Structural and antimicrobial studies of potassium hydrotris(2-mercaptobenzathiazolyl)borate and its organotin(IV) derivatives

Potassium hydrotris(2-mercaptobenzathiazolyl)borate (KL) was formed by the solid state reaction of potassium borohydride and 2-mercaptobenzathiazoline. This ligand was reacted with R _n SnCl_4?n (R =?methyl, butyl and phenyl, n =?2 and 3) in dichloromethane and four different neutral organotin(IV) complexes were obtained. All compounds were characterized by elemental analyses, FT-IR and multinuclear NMR (¹H, ¹³C, ¹¹ B and ¹¹⁹Sn) spectroscopy. Spectroscopic data indicate the six-coordinated nature of tin in its di and triorganotin(IV) complexes.

To check the toxic potential of the ligand and its organotin(IV) complexes, selected bacterial (E. coli, S. epidemidis and S. dysenteriae) and fungal (A. niger, C. albicanes and A. flaves) species were screened. The results were compared with standard drugs kinamycine and miconazole for bacterial and fungal activity, respectively. The toxicity of the organotin(IV) complexes depends on the number and nature of organic groups attached to the tin atom; triorganotin(IV) complexes exhibit better inhibition than diorganotin(IV) complexes. All compounds were also screened on the cyanobacterial strains (Aulosira fertillissma, Anabaena variabilis, Anabaena species and Nostoc muscorum). Results show that the compounds inhibit the growth of organisms at very low concentration.     

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 structural characterization of organotin(IV) complexes derived from reaction of 2,3-diphenylpropionic acid and various alkyltin salts

Five new organotin(IV) complexes, [(R₃Sn)(O₂C₁₅H₁₃)] _n (R?=?Me: 1; nBu: 2), [RSn(O)(O₂C₁₅H₁₃)]₆ (R?=?Ph: 3), [(R₂Sn)₂(O₂C₁₅H₁₃)₂(μ ₃-O)]₂ (R?=?Me: 4), and [(R₂Sn)(O₂C₁₅H₁₃)₂] (R?=?nBu: 5), have been prepared by the reaction of 2,3-diphenylpropionic acid and the corresponding organotin chloride with sodium ethoxide in methanol. All the complexes were characterized by elemental analysis, FT-IR, NMR (¹H, ¹³C, ¹¹⁹Sn) spectroscopy, TGA, and X-ray crystallography. The structural analyses reveal that 1 and 2 are 1-D infinite polymeric chains with Sn in syn–anti conformation. Complex 3 has a drum structure with six Sn centers. Complex 4 has a supramolecular chain-like ladder through weak intermolecular Sn?···?O interactions. Complex 5 is a monomer, connected into a 1-D polymer through intermolecular C–H?···?O interactions. Complexes 1 and 5 crystallize in the orthorhombic space groups P212121 and P21212, which are chiral space groups.     

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.     

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.     

Syntheses,structural characteristics,and antimicrobial activities of new organotin(IV) 3-(4-bromophenyl)-2-ethylacrylates

New organotin(IV) carboxylates, [n-Bu₂SnL₂] (1), [Et₂SnL₂] (2), [Me₂SnL₂] (3), [n-Oct₂SnL₂] (4), [n-Bu₃SnL] _n (5), [Me₃SnL] _n (6), and [Ph₃SnL] _n (7), where L?=?3-(4-bromophenyl)-2-ethylacrylate, were synthesized and characterized by elemental analysis, FT-IR, and multinuclear NMR (¹H, ¹³C, and ¹¹⁹Sn). Spectroscopic studies confirm coordination of L to the organotin moiety via COO group. Single-crystal X-ray analysis reveals bridging mode of coordination in 6. Packing diagram established a supramolecular cage-like structure for 6 due to Sn–O interactions (3.287?Å). Subsequent antimicrobial activities proved them to be active biologically.     

Synthesis and spectroscopic characterization of new organotin(IV) complexes with bis(3,5-dimethylpyrazol-1-yl)dithioacetate

New organotin(IV) derivatives containing the anionic ligand bis(3,5-dimethylpyrazolyl)dithioacetate [L₂CS₂]^? have been synthesized by reaction of SnR _n X_{4? n} (R?=?Me, Ph, ⁿ Bu or Cy; n?=?1–3) acceptors and Li[L₂CS₂]. Mononuclear complexes of the type [L₂CS₂]R _n SnCl_{4? n ?1}} have been obtained and fully characterized by elemental analyses and FT-IR in the solid state, and by NMR (¹H and ¹¹⁹Sn) spectroscopy, conductivity measurements and electrospray ionization mass spectrometry (ESI-MS) in solution. ESI-MS spectra of methanol solutions of diorganotin derivatives, recorded with fragmentor potentials of 0, 50, 100 and 150?V, show the occurrence at 150?V of peaks attributable to the loss of the CS₂ group from the ligands and the formation of stable tetraorganodistannoxane species.     

Synthesis and characterization of new organotin(IV) complexes with polyfunctional ligands

New mono-, di- and tri-organotin(IV) derivatives containing the neutral bis(2-pyridylthio)methane ligand, [(pyS)₂CH₂] and tris(2-pyridylthio)methane ligand, [(pyS)₃CH] have been synthesized from reaction with SnR_nCl_4−n (R = Me, ⁿBu, Ph and Cy, n = 1-3) acceptors. Mono-nuclear adducts of the type {[(pyS)₂CH₂]R_nSnCl_4−n} and {[(pyS)₃CH]R_nSnCl_4−n} have been obtained and characterized by elemental analyses, FT-IR, ESI-MS, multinuclear (¹H and ¹¹⁹Sn) NMR spectral data. The ¹H and ¹¹⁹Sn NMR and ESI-MS data suggest for the triorganotin(IV) derivatives a complete dissociation of the compounds in solution. The mono- and di-organotin(IV) derivatives show a greater stability in solution, and their spectroscopic data are in accordance with the existence of six-coordinated RSnCl₃N₂ or R₂SnCl₂N₂ species.     

Synthesis, characterization and hydrolytic behavior of new bis(2-pyridylthio)acetate ligand and related organotin(IV) complexes

The new sodium bis(2-pyridylthio)acetate ligand, Na[(pyS)₂CHCO₂], has been prepared in ethanol solution using 2-mercaptopyridine, dibromoacetic acid and NaOH. New mono- and di-organotin(IV) derivatives containing the anionic bis(2-pyridylthio)acetate have been synthesized from reaction between SnR_nCl_4−n (R = Me, Ph and ⁿBu, n = 1-2) acceptors and Na[(pyS)₂CHCO₂]. Mono-nuclear complexes of the type {[(pyS)₂CHCO₂]R_nSnCl_4−n−1} have been obtained and characterized by elemental analyses, FT-IR, ESI-MS, multinuclear (¹H and ¹¹⁹Sn) NMR spectral data and X-ray crystallography. ESI-MS spectra of methanol solution of the complexes show the existence of hydrolysed species. Attempts to crystallize the dimethyltin(IV) derivative (3), from acetonitrile solution yield the dimeric dicarboxylatotetramethyldistannoxane (8), which was characterized by single crystal diffraction analysis.     

Synthesis and characterization of organotin(IV) compounds with Schiff base of o-vanillin-2-thiophenoylhydrazone

Seven Schiff base adducts of organotin(IV), RSnLCl₂, which L is o-vanillin-2-thiophenoylhydrazone, and R is n-C₄H₉ (1), Me (2), Ph (3), and [R₂SnL], which L is o-vanillin-2-thiophenoylhydrazone, R is n-C₄H₉ (4), Me (5), Ph (6), PhCH₂ (7) have been synthesized. Those products were characterized by elemental analysis, IR, ¹H, ¹³C and ¹¹⁹Sn NMR spectra. The crystal and molecular structures of compounds 1, 4, and 6 have been determined by X-ray single crystal diffraction. In the crystal of compound 1 the tin atom is rendered six-coordinate in a distorted octahedral configuration by coordinating with the N atom of the Schiff base ligand, in compounds 4 and 6 the central tin atoms are five-coordinate in distorted trigonal-bipyramidal geometry and the comparison of the IR spectra reveal that disappearance of the bands assigned to carboxyl unambiguously conforms the ligand coordinate with the tin atom in enol form.     

New organotin(IV) complexes of nicotinamide, isonicotinamide and some of their novel phosphoric triamide derivatives: Syntheses, spectroscopic study and crystal structures

Three novel phosphoramidate ligands with formula , R = Nicotinamide(nia), R′ = NHC(CH₃)₃(L₁), NH(C₆H₁₁) (L₂); R = isonicotinamide(iso), NH(C₆H₁₁) (L₃) and their new organotin(IV) complexes with formula SnCl₂(CH₃)₂(X)₂, X = L₁ (C₁), L₂ (C₂), L₃ (C₃) plus SnCl₂(CH₃)₂(L₄)₂(C₄), L₄ = isoP(O)[NHC(CH₃)₃]₂, were synthesized and characterized by ¹H, ¹³C, ³¹P,¹¹⁹Sn NMR, IR, UV-Vis spectroscopy and elemental analysis. Two novel complexes of nia and iso with formula SnCl₂(CH₃)₂(X)₂, X = nia (C₅), iso (C₆) were also prepared and all the complexes were spectroscopically studied in comparison to their related ligands and to each other. The crystal structure of complexes C₁, C₃, C₄, and C₅ were determined by X-ray crystallography. -Sn-Cl···H-N- major hydrogen bonds beside other electrostatic interactions produced a three dimensional polymeric cluster in the crystalline lattice of C₁, C₃, C₅ and a two dimensional polymeric chain in C₄. Results showed that coordination of the phosphoramidate ligand (L₄) to Sn in C₄ has been occurred from the nitrogen site of the pyridine ring similar to C_5,C₆ in which there is no PO donor site; however, in C₁ and C₃ the active donor site of corresponding ligands is PO. It seems that in these complexes there is a competition between PO and N_pyridine donor sites and the influential factor which determines the winner site is the type of substituents on phosphorus atom.     

Bioactive versatile azomethine complexes of organotin(IV) and organosilicon(IV)

Diorganotin(IV) and diorganosilicon(IV) derivatives of the types R₂MCl(TSCZ) and R₂M(TSCZ)₂ (where TSCZ is the anion of a thiosemicarbazone ligand, R=Ph or Me and M=Sn or Si) have been synthesized and characterized by elemental analyses, molecular weight determinations and conductivity measurements. The mode of bonding has been established on the basis of IR and ¹H, ¹³C ²⁹Si and ¹¹⁹Sn NMR spectroscopic studies. Some of the representative complexes have also been evaluated for their antimicrobial effects on different species of pathogenic fungi and bacteria in vivoas well as in vitro.The results of these investigations are reported. © 1998 John Wiley & Sons, Ltd.     

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 and coordination chemistry of organotin(IV) complexes of 2,3-methylenedioxyphenylpropenoic acid

The synthesis, spectroscopy, and antitumor behavior of organotin(IV) complexes of 2,3-methylenedioxyphenylpropenoic acid are described. The spectroscopic data indicate 1 : 2 and 1 : 1 metal to ligand stoichiometry in case of di- and trioganotin(IV) compounds and hypervalency of Sn(IV) in trigonal bipyramidal and octahedral modes. Mass spectrometric and elemental analysis data support the solid and solution spectroscopic results. The complexes have been evaluated in vitro against crown gall tumor and bio-activity screenings showed in vitro biological potential. The nature of covalent attachments (methyl, ethyl, n-butyl, phenyl, and n-octyl) of Sn(IV) played a decisive role for bioactivity. All the compounds have been studied in solution by NMR (¹H, ¹³C) and also in solid state using FTIR, mass spectrometry, and by X-ray crystallography. The molecular structure of Et₂Sn(IV) and Me₃Sn(IV) derivatives confirm the behavior of di- and tri-organotin(IV) compounds in solid state. Mono-organotin derivatives are octahedral both in solid and solution.