Synthesis, Characterization, and Structural Studies of Mixed-Ligand Diorganotin Esters, [R2Sn(OP(O)(OH)Ph)(OS(O)2R1)]n [R = n-Bu, R1 = Me (1), n-Pr (2); R = Et, R1 = Me (3)] with 1D and 3D Coordination Polymeric Motifs

Carbon-Sulfur Bond Cleavage in Methanesulfonate on Diorganotin Quinaldate Platform - Synthesis and Characterization of [(n-Bu2SnL)2SO4]

The synthesis of mixed ligand di-n-butyltin complexes, [(n-Bu2SnL1-3)2SO4], 2-4 (HL1-3=2-quinoline/ 1-isoquinoline/ 4-methoxy-2-quinoline carboxylic acid) has been realized by reacting n-Bu2Sn(OMe)OSO2Me, 1 a with the corresponding quinaldic acid under solvothermal conditions. The observed transformation of methane sulfonate to sulfate anion represents a rare example of C-S bond cleavage on the organotin scaffolds, n-Bu2Sn(L1-3)OSO2Me, which have been identified as en route intermediates by NMR and X-ray crystallography. Analogous reaction when extended with Me2Sn(OMe)OSO2Me, 1 b and HL2 yields [(Me2Sn)2(L2)3(OSO2Me)], 5 as partially disproportionated product of Me2Sn(L2)OSO2Me. The solid-state structures of 2-5 reveal variable modes of coordination of the ligands to afford molecular and polymeric motifs.

Approach to Di/Triorganotin(IV) Cations via Hydrolysis of Stannate Salts Bearing Alkanesulfonate Ligands

An in-depth study of the class of organotin cations bearing weakly coordinating trifluoromethanesulfonate/arylsulfonate has led to key insights into their stability, structural aspects, and role as catalysts. Related chemistry with alkanesulfonate ligands remains a missing link due to the strong Sn-O bond. The study reported herein describes the scope of diorganostannates, [n-Bu₄N][R₂Sn(OSO₂R¹)₃] (R = n-Bu, R¹ = Me(1), Et(2); R = Ph, R¹ = Me(3)), as reactive substrates in the presence of adventitious water to afford [n-Bu₂SnOH(OSO₂Me)] (4), [n-Bu₂Sn(H₂O)₄][n-Bu₄N][OSO₂Et]₃·H₂O (5), and [Ph₂Sn(H₂O)₄][n-Bu₄N]₂[OSO₂Me]₄ (6), respectively, the latter two being the first examples of salt cocrystals comprising tetra(aqua)diorganotin cations. Hydrolysis of 3 in the presence of 1,4-bis((1H-imidazol-1-yl)methyl)benzene (bix) as the N-donor ligand proceeds via disproportionation and yields [Ph₃Sn(bix)](OSO₂Me) (7) along with an insoluble solid, likely derived from the hydrolysis of PhSn(OSO₂Me)₃. Direct evidence of this phenomenon can be gleaned from ESI-MS of 3, which identifies mass clusters corresponding to [Ph₃Sn(OSO₂Me)₂]^- and [PhSn(OSO₂Me)₃-H⁺]^-. X-ray crystallographic studies of 1-7 are reported to establish their structural identity and the role of alkanesulfonate anions in the formation of supramolecular assemblies.

Synthesis, characterization of dialkylated erythrosin B derivatives and their utility as a propitious anti-microbial agent

The development of small molecule based drugs as an antimicrobial agent is an important area of research nowadays. In the present work, two new molecular entities based on dialkylated erythrosin B has been synthesized via Arbuzov type of rearrangement using dialkyl sulphite as a reagent in the presence of Et3N. Ethyl and methyl based dialkylated derivatives of erythrosin B were characterized using 1H NMR, 13C NMR and HRMS data. Keeping in mind the biological safety of erythrosin B, synthesized derivatives were checked for their antimicrobial activity against the microbial strains Escherichia coli (E.coli). The two were found to be effective against the E. coli with the antimicrobial activity similar to that of Ampicillin. Further, the trend of antimicrobial activity has been supported by DFT data analysis and it was observed that compound, B with low HOMO (–5.93 eV) and LUMO (–3.11 eV) energies is a better antimicrobial agent than compound A.

Synthesis, characterization and hydrolytic stability of diorganotin(IV)bis(O-alkyl alkylphosphonate)s

Diorganotinbis(O-alkyl alkylphosphonate)s, R2Sn(O2P(OR1)R1)2 [R1 = Me, R = Me (1), Et (2), n-Bu (3); R1 = Et, R = Me (4), Et (5), n-Bu (6)] have been synthesized from the reaction between dimethyl/diethyl/di-n-butyltin dichloride and dialkyl alkylphosphonates, (R1O)2P(O)R1, in a solvent-free medium (120 °C, 18 h). X-ray crystal structure of 1 reveals two independent molecules in the unit cell that form one-dimensional polymeric motifs by virtue of bridging bidentate phosphonate groups. The structural attribute of each polymeric chain represents an orderly infinite array of -[Sn-O-P-O-]2 8-membered puckered cyclic rings with hexa-coordinated tin atoms. The structure of 2 resembles that of 1 and exhibits nearly identical structural parameters. The presence of C–H···O hydrogen bonding interactions involving P-OMe and (or) phosphonate (P=O) groups in both 1 and 2 afford the formation of two- and three-dimensional structural motifs, respectively. The phase purity and structural integrity of the bulk sample of 1 upon exposure to water has been ascertained by powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). All the compounds reported herein have been characterized by IR and multinuclear (1H, 13C, 31P, 119Sn) NMR spectral studies.

Synthesis, characterization and selective de-esterification of diorganotinbis(O-methylphosphite)s

A one-pot reaction between di-n-butyl/diethyl/dimethyltin dichloride and dimethylphosphite (MeO)2P(O)H in a solvent free medium (120 °C, 18 h) proceeds smoothly to yield the corresponding diorganotinbis(O-methylphosphite)s, [R2Sn(OP(O)(OMe)H)2]n [R = n-Bu (1), Et (2), Me (3)]. The identity of 1-3 has been established by IR, multinuclear ((1)H, (13)C, (31)P, (119)Sn) NMR, powder X-ray diffraction (PXRD) and X-ray crystallography. The coordination framework in each case adopts a one-dimensional structural motif comprising an infinite array of eight-membered [Sn-O-P-O]2 cyclic rings, with the phosphite ligands acting in a bridging bidentate mode. The structures are extended to two- (for 1) and three-dimensional (for 2, 3) assemblies by virtue of C-H···O hydrogen bonding interactions. The stability and bulk properties of 1-3 have been investigated upon exposure to humid laboratory conditions using (1)H NMR, PXRD and SEM studies. The results conform to a unique chemical modification of 1-3 involving selective de-esterification of P-OMe bonds and the formation of corresponding diorganotinbis(phosphite)s, [R2Sn(OP(O)(OH)H)2]n (1a-3a), as insoluble solids. The results obtained from impedance studies (σ = 10(-4)-10(-6) S cm(-1); E(a) = 0.33-0.42 eV) reveal potential application of 1a-3a as proton conducting materials.