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     

Triorganotin(IV) complexes containing multifunctional meso‐dimercaptosuccinic acid ligand: Syntheses,characterizations, and crystal structures

Four triorganotin complexes of the types [(R₃Sn)₂(C₂H₂S₂)(COOH)₂] ⋅ 2Et₂O (R = Ph, 1 ) and (R₃Sn)₂(C₂H₂S₂)(COOH)₂ (R = Me 2 , R = n‐Bu 3 , and R = PhCH₂ 4 ) have been obtained by the reaction of meso‐dimercaptosuccinic acid and sodium ethoxide with triorganotin(IV) chloride in 1:2:2 stoichiometry. All the complexes were characterized by elemental analyses, IR spectroscopy, and NMR spectroscopy. Furthermore, complexes 1 and 2 were characterized by X‐ray diffraction analyses, which revealed that complexes 1 and 2 are mononuclear structures and further interlinked by intermolecular C H⋅⋅⋅O and O H⋅⋅⋅O hydrogen bonds, respectively. © 2009 Wiley Periodicals, Inc. Heteroatom Chem 20:50–55, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20511     

Syntheses,characterizations, and crystal structures of tri‐ and diorganotin (IV) derivatives with 2‐mercapto‐5‐methyl‐1,3,4‐thiadiazole

A series of organotin(IV) complexes with 2‐mercapto‐5‐methyl‐1,3,4‐thiadiazole (HL) of the type R₃ Sn(L) (R = Me 1 ; Bu 2 ; Ph 3 ; PhCH₂ 4 ) and R₂Sn(L)₂ (R = CH₃ 5 ; Ph 6 ; PhCH₂ 7 ; Bu 8 ) have been synthesized. All complexes 1–8 were characterized by elemental analysis, IR,¹H, ¹³ C, and ¹¹⁹Sn NMR spectra. Among these, complexes 1 , 3 , 4 , and 7 were also determined by X‐ray crystallography. The tin atoms of complexes 1 , 3 , and 4 are all penta‐coordinated and the geometries at tin atoms of complexes 3 and 4 are distorted trigonal–bipyramidal. Interestingly, complex 1 has formed a 1D polymeric chain through Sn and N intermolecular interactions. The tin atom of complex 7 is hexa‐coordinated and its geometry is distorted octahedral. © 2006 Wiley Periodicals, Inc. Heteroatom Chem 17:353–364, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20215     

Synthesis,properties and crystal structural characterization of diorganotin(IV) derivatives of 2‐mercapto‐6‐nitrobenzothiazole

The diorganotin(IV) dichlorides R₂SnCl₂ (R: Ph, PhCH₂ or n‐Bu) react with 2‐mercapto‐6‐nitrobenzothiazole (MNBT) in benzene to give [Ph₂SnCl(MNBT)] ( 1 ), [(PhCH₂)₂Sn(MNBT)₂] ( 2 ) and [(n‐Bu)₂Sn(MNBT)₂] ( 3 ). The three complexes have been characterized by elemental analysis and IR, ¹H, ¹³C and ¹¹⁹Sn NMR spectroscopies. X‐ray studies of the crystal structures of 1 , 2 and 3 show the following. The tin environment for complex 1 is distorted cis‐trigonal bipyramid with chlorine and nitrogen atoms in apical positions. The structure of complex 2 is a distorted octahedron with two benzyl groups in the axial sites. The geometry at the tin atom of complex 3 is that of an irregular octahedron. Interestingly, intra‐molecular non‐bonded Cl…S interactions and S…S interaction were recognized in the crystallographic structures of 1 and 3 respectively. As a result, complex 1 is a polymer and complex 3 is a dimer. Copyright © 2003 John Wiley & Sons, Ltd.     

Syntheses,characterizations and crystal structures of new triorganotin complexes with 2‐mercaptopyrimidine and 4‐amino‐2‐mercaptopyrimidine

Four triorganotin(IV) complexes with 2‐mercaptopyrimidine (HSpym) and 4‐amino‐2‐mercaptopyrimidine (HSapym) of the type, R₃SnL (L= Spym, R=Ph, 1; R=PhCH₂, 2; L=Sapym, R=Ph, 3; R=PhCH₂, 4), were synthesized. All the complexes 1–4 have been characterized by elemental, IR, ¹H NMR, and X‐ray crystallography diffraction analyses, which revealed that the structures of 1–4 are penta‐coordinated with R₃Sn‐coordinated to the thiol S and heterocyclic N atoms, and the structural distortion for each is a displacement from tetragonal toward trigonal bipyramidal geometry. The complex 1 is a one‐dimensional chain complex, while compounds 3 and 4 are dimers due to the existence of N···H hydrogen bonding. © 2005 Wiley Periodicals, Inc. Heteroatom Chem 16:69–75, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20068     

Syntheses and crystal structures of triorganotin (IV) derivatives with 2,2′‐bipyridine‐4,4′‐dicarboxylic acid

Four organotin complexes with 2,2′‐bipyridine‐4,4′‐dicarboxylic acid, H₂dcbp: (Ph₃n)₂(dcbp) 1 , [(PhCH₂)₃n]₂(dcbp) ⋅ 2CH₃OH 2 , [(Me₃Sn)₂(dcbp)]_n 3 , [(Bu₃Sn)₂(dcbp)]_n 4 have been synthesized. The complexes 1–4 were characterized by elemental, IR, ¹H, ¹³C, ¹¹⁹n NMR, and X‐ray crystallographic analyses. Crystal structures show that complex 1 is a monomer with one ligand coordinated to two triorganotin moieties, and a 1D infinite polymeric chain generates via intermolecular C H⋅⋅⋅N hydrogen bond; complex 2 is also a monomer and forms a 2D network by intermolecular O–H⋅⋅⋅O weak interaction; both of complexes 3 and 4 form 2D network structures where 2,2′‐bipyridine‐4,4′‐dicarboxylate acts as a tetradentate ligand coordinated to trimethyltin and tri‐n‐butyltin ions, respectively. © 2009 Wiley Periodicals, Inc. Heteroatom Chem 20:19–28, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20506     

Syntheses,characterizations, and crystal structures of organotin(IV) chloride complexes with 4,4′‐bipyridine

The organotin(IV) chlorides R_nSnCl_4−n (n = 3, R = Ph, PhCH₂, n−Bu; and n =2, R = n−Bu, Ph, PhCH₂) react with 4,4′‐bipyridine (4′4‐bpy) to give [(Ph₃SnCl)₂(4,4′‐bpy)_1.5(C₆H₆)_0.5] ( 1 ), [(PhCH₂)₃‐ SnCl]₂ (4,4′‐bpy) ( 2 ), [(n−Bu)₃SnCl]₂(4,4′‐bpy) ( 3 ), [(n−Bu)₂SnCl₂(4,4′‐bpy)] ( 4 ), [Ph₂SnCl₂(4,4′‐bpy)] ( 5 ), and [(PhCH₂)₂SnCl₂(4,4′‐bpy)] ( 6 ). The new complexes have been characterized by elemental analyses, IR, ¹H, ¹³C, ¹¹⁹Sn NMR spectroscopy. The structures of ( 1 ), ( 2 ), ( 4 ), and ( 6 ) have been determined by X‐ray crystallography. Crystal structures of ( 1 ) and ( 2 ) show that the coordination number of tin is five. In complex ( 1 ), two different molecules exist: one is a binuclear molecule bridged by 4,4′‐bpy and another is a mononuclear one, only one N of 4,4′‐bpy coordinate to tin. Complex ( 2 ) contains an infinite 1‐D polymeric binuclear chain by weak Sn…Cl intermolecular interactions with neighboring molecules. In the complexes ( 4 ) and ( 6 ), the tin is six‐coordinate, and the 4,4′‐bpy moieties bridge adjacent dialkyltin(IV)dichloride molecules to form a linear chain. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:338–346, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20016     

Diorganotin(IV) compounds derived from n‐methyl‐2,2′‐diphenolamine and 2,2′‐diphenolamine

The reaction of N‐methyl‐2,2′‐diphenolamine 1 and 2,2′‐diphenolamine 2 with some diorganotin(IV) oxides [R1/2SnO: R¹ = Me, n‐Bu, t‐Bu and Ph] led to the syntheses of diorgano[N‐methyl‐2,2′‐diphenolato‐O,O′,N]tin (IV) 3–6 and diorgano[2,2′‐diphenolato‐O,O′,N]tin (IV) 7–9 . All compounds (except 7 ) studied in this work were characterized by ¹H, ¹³C, ¹¹⁹Sn NMR, infrared, and mass spectroscopy. Their ¹¹⁹Sn NMR data show that the tin atom is tetracoordinated in CDCl₃ but penta and hexacoordinated in DMSO‐d₆. © 1999 John Wiley & Sons, Inc. Heteroatom Chem 10: 133–139, 1999     

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.     

Synthesis and Structural Characterization of Some Novel Trialkylsilyl‐substituted Lithium Benzyl Complexes [Li(tmeda)][CHRSiMe2R′] (R = Ph, 3,5‐Me2C6H3; R′ = Me,tBu, Ph)

The reactions of PhCH₂SiMe₃ ( 1 ), PhCH₂SiMe₂^tBu ( 2 ), PhCH₂SiMe₂Ph ( 3 ), 3,5‐Me₂C₆H₃CH₂SiMe₃ ( 4 ), and 3,5‐Me₂C₆H₃CH₂SiMe₂^tBu ( 5 ) with ⁿBuLi in tetramethylethylenediamine (tmeda) afford the corresponding lithium complexes [Li(tmeda)][CHRSiMe₂R′] (R, R′ = Ph, Me ( 6 ), Ph, ^tBu ( 7 ), Ph, Ph ( 8 ), 3,5‐Me₂C₆H₃, Me ( 9 ), and 3,5‐Me₂C₆H₃, ^tBu ( 10 )), respectively. The new compounds 5 , 7 , 8 , 9 and 10 have been characterized by ¹H and ¹³C NMR spectroscopy, compounds 7 , 8 and 9 also by X‐ray structure analysis.     

Syntheses and Crystal Structure of Six－coordinated Diorgnotin Complexes with 2,5－Dimercapto－4－phenyl－1,3,4－thiodiazole

The reactions of diorganotin dichloride [Ph_2SnCl_2, (PhCH_2)_2-SnCl_2 or (n-Bu)_2SnCl_2] with potassium salt of 2,5-dimercapto-4-phenyl-1, 3, 4-thiodiazole gave complexes R_2Sn (S_3N_2C_8H_5)_2(4: R=Ph; 5: R=PhCH_2 and 6: R=n-Bu), respectively.Characterizations were carried out for all complexes by IR, ~1HNMR spectra and X-ray crystallography analysis. Including theSn…N interaction, the three complexes all have six-coordinateddistorted octahedral geometry. Based on the requence of stereo-chemical constraint sequence, phenyl≈benzyl>n-butyl, the lessthe effect of the stereochemical constraint of R groups, the     

Crystal and molecular structures of atropisomeric N‐aryl‐1,2,3,4‐tetrahydro‐3,3‐dimethyl‐2,4‐quinolinediones

The crystal structures of N‐aryl‐1,2,3,4‐tetrahydro‐3,3‐dimethyl‐2,4‐quinolinediones bearing methoxy‐ ( 1 ), methyl‐ ( 2 ), and chloro‐ ( 3 ) substituents in 2′‐position of the phenyl ring have been determined by X‐ray crystal structure analysis. The heterocyclic ring in 1–3 adopts an envelope conformation, with the smallest ring puckering in the ortho‐chloro derivative 3 . The N‐aryl ring is almost perpendicular with respect to the quinoline‐2,4‐dione ring. The corresponding dihedral angle values are 83.2(1)°, 80.0(9)°, and 83.4(2)° in 1, 2 and 3 , respectively. The hydrogen bond of C H⋅⋅⋅O type joins the molecules of the ortho‐methoxy derivative 1 into dimers. The supramolecular structure also contains two C H⋅⋅⋅π interactions that link the hydrogen‐bonded dimers into sheets. In ortho‐methyl derivative 2 , one C H⋅⋅⋅π interaction generates infinite chains, whereas two C H⋅⋅⋅O hydrogen bonds and three C H⋅⋅⋅π interactions in the ortho‐chloro derivative 3 form three‐dimensional framework. © 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:325–331, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20436     

Synthesis,Characterization and Crystal Structure of (PhCH2)2Sn(S2CENt2) and (PhCH2)2Sn(S2CNC4H8)2

Two new dibenzyltin bisditiocarbamates(PhCH2)2 Sn(S2CNEt2)2(1) and (PhCH2)2 Sn(S2CNC4H8)2(2) were synthesized by the reaction of dibenzyltin dichloride with dithiocarbamates and characterized by elemental analysis ,IR,^1H NMR and MS spectra.The crystal structures were determined by X-ray single crystal diffraction analysis.In both complexes,the tin atom is six-coordinated in a distorted octahedral configuration.In the crystals of 1,the molecular packing in unit cell reveals that the two adjacent molecules are symmetrically linked to each other in dimers by two Sn S interactions of 0.3816nm.In the crystals of 2,the molecules are packed in the unit cell in one-dimensional chain structure linked by weaker intermolecular S S conmtacts.     

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     

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

Four new diorganotin(IV) complexes of N‐(5‐halosalicylidene)tryptophane, R₂Sn[5‐X‐2‐OC₆H₃CH?NCH(CH₂Ind)COO] [Ind = 3‐indolyl; R, X = Et, Cl ( 1 ); Et, Br( 2 ); n‐Bu, Cl ( 3 ); n‐Bu, Br ( 4 )], were synthesized and characterized by elemental analysis, IR and NMR (¹H, ¹³C and ¹¹⁹Sn) spectra. The crystal structures of complexes 1 – 3 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. Intermolecular weak interactions in 1–3 link molecules, respectively, into a two‐dimensional array, a one‐dimensional infinite chain and a one‐dimensional double‐chain supramolecular structure. Bioassay results of the compounds indicated that the dibutyltin complexes 3 and 4 have potent in vitro cytotoxic activity against two human tumor cell lines, CoLo205 and Bcap37, while the diethyltin complexes 1 and 2 display weak cytotoxic activity. Copyright © 2008 John Wiley & Sons, Ltd.     

Spectroscopic and X‐ray structural characterization of new polymeric organotin(IV) carboxylates and their in vitro antifungal activities: Part II

The reactions of R₃SnCl (R = Me, Bu or Ph) with sodium 4‐phenylbutyrate, Na(OPh^b), in EtOH yielded three polymeric triorganotin carboxylates, namely [R₃Sn(OPh^b)]_n (R = Me ( 1 ), Bu ( 2 ) or Ph ( 3 )). All complexes were spectroscopically characterized using Fourier transform infrared, ¹¹⁹Sn Mössbauer, ¹H NMR, ¹³C{¹H} NMR and ¹¹⁹Sn{¹H} NMR spectral techniques. In addition, the crystal structures of 1 and 3 were determined using single‐crystal X‐ray diffraction. Their polymeric structures are sustained by bridging carboxylates which connect two five‐coordinate Sn(IV) centres. Each metallic cation displays a distorted trigonal bipyramidal coordination geometry (Addison's parameters ranging from 0.84 in 1 to 0.77–0.91 in 3 ), with the oxygen atoms occupying the apical positions and the organic groups at the equatorial corners. The one‐dimensional zigzag chains of 1 propagate along the b ‐axis, whereas 3 displays wave‐like double polymeric chains along the b ‐axis. For both 1 and 3 , parallel one‐dimensional polymeric chains are interconnected by C─H⋅⋅⋅π interactions. The antifungal activity of 1 – 3 was screened against Candida albicans (ATCC 18804), C. tropicalis (ATCC 750), C. glabrata (ATCC 90030), C. parapsilosis (ATCC 22019), C. lusitaniae (CBS 6936) and C. dubliniensis (clinical isolate 28). The antifungal activity of 3 was noteworthy since it was not only more active than 1 and 2 , but also more active than the control drugs (nystatin and fluconazole nitrate) in some cases.     

Über den Phosphandiyl‐Transfer von invers‐polarisierten Phosphaalkenen R1P=C(NMe2)2 (R1 = tBu,Cy, Ph,H) auf Phospheniumkomplexe [(η5‐C5H5)(CO)2M=P(R2)R3] (R2 = R3 = Ph; R2 = tBu,R3 = H; R2 = Ph,R3 = N(SiMe3)2)

Phosphanediyl Transfer from Inversely Polarized Phosphaalkenes R¹P=C(NMe₂)₂ (R¹ = tBu, Cy, Ph, H) onto Phosphenium Complexes [(η⁵‐C₅H₅)(CO)₂M=P(R²)R³] (R² = R³ = Ph; R² = tBu, R³ = H; R² = Ph, R³ = N(SiMe₃)₂) Reaction of the freshly prepared phosphenium tungsten complex [(η⁵‐C₅H₅)(CO)₂W=PPh₂] ( 3 ) with the inversely polarized phosphaalkenes RP=C(NMe₂)₂ ( 1 ) ( a : R = tBu; b : Cy; c : Ph) led to the η²‐diphosphanyl complexes ( 9a‐c ) which were isolated by column chromatography as yellow crystals in 24‐30 % yield. Similarly, phosphenium complexes [(η⁵‐C₅H₅)(CO)₂M=P(H)tBu] (M = W ( 6 ); Mo ( 8 )) were converted into (M = W ( 11 ); Mo ( 12 )) by the formal abstraction of the phosphanediyl [PtBu] from 1a . Treatment of [(η⁵‐C₅H₅)(CO)₂W=P(Ph)N(SiMe₃)₂] ( 4 ) with HP=C(NMe₂)₂ ( 1d ) gave rise to the formation of yellow crystalline ( 10 ). The products were characterized by elemental analyses and spectra (IR, ¹H, ¹³C‐, ³¹P‐NMR, MS). The molecular structure of compound 10 was elucidated by an X‐ray diffraction analysis.     

Self‐Assembly of Dialkyltin Moieties and Mercaptobenzoic Acid into Macrocyclic Complexes with Hydrophobic “Pseudo‐Cage” or Double‐Cavity Structures: Supramolecular Infrastructures Involving Intermolecular C?H⋅⋅⋅S Weak Hydrogen Bonds and π–π Interactions

Four novel organotin complexes of two types—[R₂Sn(o‐SC₆H₄CO₂)]₆ (R=Me, 1 ?H₂O; nBu, 2 ) and {[R₂Sn(m‐CO₂C₆H₄S)R₂Sn(m‐SC₆H₄CO₂)SnR₂]O}₂ (R=Me, 3 ; nBu, 4 )—have been prepared by treatment of o‐ or m‐mercaptobenzoic acid and the corresponding R₂SnCl₂ (R=Me, nBu) with sodium ethoxide in ethanol (95 %). All the complexes were characterized by elemental analysis, FT‐IR and NMR (¹H, ¹³C, ¹¹⁹Sn) spectroscopy, TGA, and X‐ray crystallography diffraction analysis. The molecular structure analyses reveal that both 1 and 2 are hexanuclear macrocycles with hydrophobic “pseudo‐cage” structures, while 3 and 4 are hexanuclear macrocycles with double‐cavity structures. Furthermore, the supramolecular structure analyses show that looser and more intriguing supramolecular infrastructures were also found in complexes 1 – 4 , which exist either as one‐dimensional chains of rings or as two‐dimensional networks assembled from the organometallic subunits through intermolecular C? H???S weak hydrogen bonds (WHBs) and π–π interactions.     

Synthesis,Structural Characterization,and Theoretical Studies of Silver(I) Complexes of Dihydrobis(2‐mercapto‐benzothiazolyl) Borate

The complexes [Ag{κ³‐S,S′,H‐H₂B(mbz)₂}(PR₃)]_x, ( 1 : x = 2, R = Ph; 2 : x = 1, R = Cy) (mbz = 2‐mercaptobenzothiazolyl) and amidine based dihydro(2‐mercaptobenzo‐thiazolyl) borates, [HN=C(Ph)–NH(R)–H₂B(mbz)] ( 3 : R = 2,6‐diisopropylphenyl and 4 : R = Ph) were synthesized and characterized by various spectroscopic methods and single‐crystal X‐ray crystallography. Complex [Ag{κ³‐S,S′,H‐H₂B(mbz)₂}(PPh₃)]₂ ( 1 ) has a dimeric structure in its crystalline state, in which central silver(I) atoms adopt a distorted trigonal bipyramid arrangement. In contrast, complex [Ag{κ³‐S,S′,H‐H₂B(mbz)₂}(PCy₃)] ( 2 ) has a monomeric structure in its crystalline state, in which the central silver(I) atoms adopt a distorted trigonal planar arrangement. Infrared spectroscopy was utilized as a tool for investigating the presence of M ··· H–B interactions. In addition, density functional theory (DFT) calculations were used to analyse the B–H ··· [M] bonding interaction in the metal borate complexes.     

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.