Xueqing Song

Comparative study of structure–activity relationship of di- and tri-organotin(IV) derivatives of amino acid and peptides

Novel non-electrolytic di- and tri-organotin(IV) derivatives of the general formula R2Sn(L/HL′) and Ph3Sn(HL/H2L′), where R is n-Bu and Ph, and L/HL is dianion/monoanion of d-penicillamine (H2L-1) and l-carnosine (H2L-2), and HL′/H2L′ is dianion/monoanion of triglycine (H3L-3) have been synthesized in 1:1 molar ratio either at pH 7.0 or pH<2.0. All n-Bu2Sn(IV) derivatives have been synthesized by the reaction of Bu2SnO with amino acid/peptides under azeotropic removal of water. Ph2Sn(IV)/Ph3Sn(IV) derivatives have been synthesized by either sodium chloride method or alkoxide method. The dibutyltin(IV) complexes synthesized at pH<2.0 possess chlorine in the coordination sphere (as revealed from molar conductance measurement in methanol) and a molecule of water in the crystal lattice. The structures of the complexes are discussed on the basis of IR, far-IR, multinuclear (1H-, 13C- and 119Sn-) NMR and 119Sn-Mossbauer spectroscopic studies. All the diorganotin(IV) derivatives possess a distorted trigonal bipyramidal structure in which D-penicillamine/peptides are tridentate coordinating through Namino, C(O)Ocarboxyl and Sthiol/Npeptide. The NH2 group bridging/hydrogen bonding may lead to the associated structure. Whereas a linear polymeric structure with a distorted trigonal bipyramidal environment around tin has been tentatively proposed for Ph3Sn(IV) derivatives in which the ligands may act as bidentate coordinating through Namino and C(O)Ocarboxyl. n-Bu2SnCl(HL-1)·H2O, synthesized at low pH, is dimeric. The anti-inflammatory activity, ALD50 and blood pressure lowering activity of the synthesized derivatives are reported. Some complexes exhibit good anti-inflammatory activities comparable to that of phenylbutazone (a comparative analysis is presented through plots). The triorganotin(IV) derivatives exhibit significantly better activities than the diorganotin(IV) derivatives.

Diorganotin(IV) Derivatives of Dipeptides Containing at Least One Essential Amino Acid Residue: Synthesis, Characteristic Spectral Data, Cardiovascular, and Anti‐inflammatory Activities

Abstract New diphenyltin(IV) derivatives of the formula Ph2SnL, where L is the dianion of glycyltryptophan (Gly‐Trp), glycylphenylalanine (Gly‐Phe), valylvaline (Val‐Val), alanylvaline (Ala‐Val), and leucylalanine (Leu‐Ala), have been synthesized by the reaction of Ph2SnCl2 and the disodium salt of the respective dipeptides. The bonding and coordination behaviour in these derivatives are discussed on the basis of IR, multinuclear 1H, 13C, and 119Sn NMR and 119Sn Mössbauer spectroscopic studies. These investigations suggest that all the dipeptides in Ph2SnL act as dianionic tridentate ligands coordinating through the COO−, NH2, and Npeptide groups. The 119Sn Mössbauer studies, together with the NMR data, suggest a trigonal‐bipyramidal geometry around tin in Ph2SnL with the phenyl groups and Npeptide in the equatorial positions, whereas a carboxylic oxygen and the amino nitrogen atom occupy the axial positions. The anti‐inflammatory and cardiovascular activities, and toxicity of all the synthesized diphenyltin(IV) derivatives of dipeptides and of n‐dibutyltin(IV) derivatives of dipeptides (synthesized and characterized earlier) viz. Gly‐Trp, Val‐Val, Ala‐Val, glycyltyrosine (Gly‐Tyr), leucyltyrosine (Leu‐Tyr), and leucylleucine (Leu‐Leu) are discussed. The n‐dibutyltin(IV) derivatives exhibit better cardiovascular and anti‐inflammatory activities than the diphenyltin(IV) analogues.

Synthesis, characterization and biological activity of dimethyltin dicarboxylates containing germanium.

A series of diorganotin dicarboxylates of the general formula (CH3)2Sn(OCOCHR3CHR2GeR1)2 where R1=(C6H5)3, (P-CH3C6H4)3, N(CH2CH2O)3, R2=C6H5, H, CH3, P-CH3OC6H4, P-ClC6H4, P-CH3C6H4, R3=CH3 and H, have been synthesized by the reaction of dimethyltin oxide with germanium substituted propionic acid in 1:2 molar ratio in toluene. The H2O formed was removed azeotropically using a Dean and Stark apparatus. All the compounds have been characterized by IR, multinuclear (1H, 13C, 119Sn) NMR, mass and Mössbauer spectroscopies. All compounds were found to have potential activity against bacteria.

Synthesis, crystal structures, cytotoxicity and qualitative structure–activity relationship (QSAR) of cis-bis{5-[(E)-2-(aryl)-1-diazenyl]quinolinolato}di-n-butyltin(IV) complexes, nBu2Sn(L)2

A series of cis-bis{5-[(E)-2-(aryl)-1-diazenyl]quinolinolato}di-n-butyltin(IV) complexes has been synthesized and characterized by (1)H-, (13)C-, (119)Sn NMR, ESI-MS (electrospray ionization mass spectrometry), IR and (119m)Sn Mössbauer spectroscopic techniques in combination with elemental analyses. The structures of four di-n-butyltin(IV) complexes, viz., (n)Bu(2)Sn(L(3))(2) (3), (n)Bu(2)Sn(L(4))(2) (4), (n)Bu(2)Sn(L(5))(2) (5) and (n)Bu(2)Sn(L(7))(2).0.5C(6)H(6) (7) (LH=5-[(E)-2-(aryl)-1-diazenyl)quinolin-8-ol) were determined by single crystal X-ray diffraction. In general, the complexes were found to adopt a distorted cis-octahedral arrangement around the tin atom. These complexes retain their solid-state structure in non-coordinating solvent as evidenced by (119)Sn and (13)C NMR spectroscopic results. The in vitro cytotoxicity of di-n-butyltin(IV) complexes (3-8) is reported against seven well characterized human tumour cell lines. The basicity of the two quinolinolato donor N and O atoms of the ligands are discussed in relation to the cytotoxicity data.

The crystal structure of tricyclohexyltin N-n-butyl dithiocarbamate

Figure 1. Molecular structure of [Cy3SnS2CNHBu]. Selected bond distances and angles: Sn(l)-C(ll) 2.147(8), Sn(l)-C(21) 2.157(9), Sn(l)-C(31) 2.105(11), Sn(l)-S(l) 2.472(3), C(1>S(1) 1.750(9), C(l)-S(2) 1.656(9), C(l)-N(l) 1.342(9)_; C(11)-Sn(l)-C(21) 107.5(4), C(11)-Sn(l)-C(31) 120.0(4), C(21)-Sn(l)C(31) 104.9(4), S(l)-Sn(l)-C(l 1) 110.2(3), S(l)-Sn(l)-C(21) 96.1(3), S(l)-Sn(l)-C(31) 114.8(3), S(l> C(l)-S(2) 122.7(5), C(l)-S(l)-Sn(l) 99.8(3), N(l)-C(l)-S(l) 114.9(7), N(l)-C(l)-S(2) 122.4(7). H-atoms omitted for clarity.

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.

New diorganotin(IV) derivatives of dipeptides: Synthesis and characteristic spectral studies

Some new diorganotin(IV) derivatives of the formulae, R2SnL, where R=Me, n-Bu, Ph, and n-Oct, and L is the dianion of histidinylalanine (H2L-1) and histidinylleucine (H2L-2) have been synthesized by the reaction of R2SnCl2 and the preformed sodium salt of the respective dipeptides. 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 dipeptides in R2SnL act as dianionic tridentate coordinating through the COO(-), NH2 and N(-)peptide groups. The 119Sn Mössbauer studies, together with the NMR data, suggest a trigonal bipyramidal geometry around tin in R2SnL with the alkyl/aryl groups and Npeptide in the equatorial positions, while a carboxylic oxygen and the amino nitrogen atom occupy the axial positions.

Synthesis, Spectroscopic Characterization: (IR, Multinuclear NMR, 119mSn Mössbauer and Mass Spectrometry), and Biological Activity (Antibacterial, Antifungal, and Cytotoxicity) of Di‐ and Triorganotin(IV) Complexes of (E)‐3‐(4‐Chlorophenyl)‐2‐phenylpropenoic Acid

Abstract In an effort to develop new organotin(IV) compounds of industrial and biological importance, a series of di‐ and triorganotin(IV) complexes of (E)‐3‐(4‐chlorophenyl)‐2‐phenylpropenoic acid with the general formula R4‐n SnL n have been synthesized by the reaction of the corresponding organotin chlorides with the sodium salt of (E)‐3‐(4‐chlorophenyl)‐2‐phenylpropenoic acid (C15H10ClO2Na) where, R = CH3, C2H5, n‐C4H9, C6H5, C6H5 · CH2, n = 1 or 2 and L = acid anion (C15H10ClO2 −). The dimeric tetraorganodicarboxylatodistannoxanes [(Me2SnL)2O]2 compound (2) and [(Bu2SnL)2O]2 compound (4), L = C15H10ClO2 −, were synthesized by the reaction of R2SnO with the ligand acid (HL) in 1:1 molar ratio with azeotropic removal of water. The structures of the complexes are discussed on the basis of IR, multinuclear (1H, 13C, 119Sn) NMR, 119mSn Mössbauer spectroscopies and mass spectrometry. The spectroscopic results substantiate that all the diorganotin(IV) derivatives possess trigonal‐bipyramidal structures in solution and octahedral geometry in the solid state. A linear polymeric trigonal‐bipyramidal structure in the solid state and a tetrahedral environment around the tin atom in non‐coordinating solvents has been proposed for the triorganotin(IV) derivatives. The Δν [Δν = νasym(COO) − νsym(COO)] values obtained from the IR data, in comparison to the ligand acid and its sodium salt, fall in the range which shows that the ligand may act as a bidentate coordinating group through the carboxyl (COO) oxygen atoms. The biological activity and LD50 data of the synthesized compounds are also reported. The triorganotin(IV) complexes exhibit significantly better activities than the diorganotin(IV) derivatives. The LD50 data show that most of the investigated compounds are cytotoxic.

CRYSTAL STRUCTURE OF TRIPHENYLTIN 4 - METHOXYBENZOATE

Figure 1. Molecular structure of [Ph3Sn02CC6H40CH3-4]. Selected bond distances and angles: Sn(l)-0(1) 2.053(2), Sn(l)-0(2) 2.793(3), Sn(l)-C(21) 2.114(3), Sn(l)-C(31) 2.113(3), Sn(l)-C(41) 2.128(3), C (1)0(1) 1.308(4), C( 1 )-0(2) 1.226(4), C(l)-C(51) 1.477(4) ; C(41)-Sn(l)-C(21) 109.66(12), C(41)-Sn(l)C(31) 106.49(12), C(21 )-Sn( 1 )-C(31) 122.00(12), 0 ( 1 )-Sn( 1 )-C(21) 109.40(10), 0(1)-Sn(l)-C(41) 97.18(10), 0(l)-C(l)-0(2) 120.8(3), C(l)-0(1)-Sn(l) 110.31(19), 0(l)-Sn(l)-0(2) 51.31(20) H-atoms omitted for clarity.

Template synthesis and structural characterization of new diorganotin(IV) tetraazamacrocyclic complexes: precursors to produce pure phase nanosized SnO2

This article describes the synthesis and characterization of several new diorganotin(IV) tetraazamacrocyclic complexes. The template condensation of anthranilic acid and diethylenetriamine with 1,2-dibromoethane or 1,3-dibromopropane in the presence of diorganotin(IV) dichlorides yielded macrocyclic complexes. The geometry and the mode of bonding of the resulting complexes were inferred from elemental analysis, UV-Vis, IR, Direct Analysis in Real Time-mass, (1H, 13C and 119Sn) NMR, and 119mSn Mössbauer spectral studies. These studies suggested that the macrocyclic ligands are tetradentate, coordinating through four nitrogens giving a skew-trapezoidal bipyramidal environment around tin in the [R2Sn(L-1)/(L-2)] (R = Me, n-Bu and Ph; H2L-1/H2L-2 = macrocyclic ligands) complexes. Thermal studies of the complexes were carried out in the temperature range 25–1000°C using thermogravimetry, derivative thermogravimetry, and differential thermal analysis techniques which provided a simple route to nanosized semi conducting SnO2 grains, identified by X-ray diffraction analysis. The particle size of the residue, obtained by pyrolysis of 2, 3, 4 and 5, determined by X-ray line broadening and transmission electron microscope were in the range ∼38–48 nm and ∼3–20 nm, respectively. The surface morphology of these residues was determined by scanning electron microscopy.