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Pro-ligand 5-[(E)-2-(3-pyridyl)-1-diazenyl]-2-hydroxybenzoic acid, H′HLmeta, was employed for the synthesis of four organotin(IV) complexes, using suitable tri- and diorganotin (IV) precursors, [nB...

A series of six new organotin(IV) compounds, namely, [nPr3Sn(HL)(MeOH)] 1, [nBu3Sn(HL)]n 2, [Bz3Sn(HL)]n 3, [Ph3Sn(HL)]n⋅nC6H6 4, [Ph3Sn(HL)(EtOH)] 5 and [nBu2Sn(L)]n 6 were synthesized by reacting appropriate tri- and di-organotin(IV) precursors with the flexible pro-ligand 5-[(E)-2-(4-pyridyl)-1-diazenyl]-2-hydroxybenzoic acid. Their solid-state structures were deduced from single crystal X-ray diffraction data and, in the case of compound 6, also by solid-state 13C and 119Sn NMR spectroscopy. Compounds 1 and 5 are mononuclear as a consequence of methanol/ethanol coordination preventing the propagation of the polymers. The monodentate oxygen atom from the carboxylate group of HL− and the tin-coordinated oxygen atom of alcohol are situated at the axial positions, while Sn-R substituents are at the equatorial sites, defining the distorted trigonal-bipyramidal coordination polyhedron. Both 1 and 5 form one-dimensional (1D) chains created by virtue of O−Hsolv⋯Npy hydrogen bonding interactions, and antiparallel running chains in 1 furnish 34-membered dinuclear macrocyclic rings occupied by SnPr3 groups. Compounds 2–4 feature a one-dimensional coordination polymer facilitated by intermolecular N→Sn bond formation with the pyridyl substituent of LH−. The axially located OOCO and Npy donor atoms and equatorial Sn-R groups give rise to a trigonal-bipyramidal geometry. While similar coordination geometries are observed for 2–4, the tri-n-butyl derivative 2 generates 60-membered macrocyclic rings where four n-butyl groups from two neighboring molecules occupy the cavities. The triphenyltin analogue 4 forms two-dimensional layers with voids filled by benzene solvate molecules, and the sterically demanding tribenzyltin groups in compound 3 result in only relatively weak C−H⋯π, C−H⋯N and van der Waals contacts. On the other hand, compound 6 is a two-dimensional (2D) coordination polymer displaying a distorted pentagonal-bipyramidal geometry around the tin atom where four oxygen atoms of two ligand molecules and the nitrogen atom of a ligand constitute the equatorial plane, while the carbon atoms of the n-butyl groups complete the axial positions. The molecules of 6 self assembled to an interesting dimeric tecton based on a four-membered Sn2O2 ring, generating large 48-membered hexanuclear macrocycles, where the cavities are filled by four di-n-butyl groups from two neighboring molecules. The solution behaviors of compounds 1–5 were judged from the results of the 119Sn NMR spectroscopic characterization.

Although several strategies have been established to circumvent the limitations of platinum-based chemotherapy, the basic problems still persist. For this purpose, the new series of heterobimetallic formulations [FcLnSnPh3] (1, 3, and 9)], [FcLnSnBu3]n (2, 4 and 8), [FcL3SnCy3] (10), and [FcL3SnR3(MeOH)] (R = Me (5), Et (6), or Pr (7)), where FcLn (n = 1–3) refers to the isomeric 2-/3-/4-ferrocenylbenzoates, was synthesized which can target cancer cells and successively support functional iron deficiencies during chemotherapy. Compounds 1–10 have been characterized by elemental analysis, and their spectroscopic properties were investigated using IR, NMR, electronic, and fluorescence techniques. The molecular structures of metallo proligands FcL1H and FcL3H and the six heterobimetallic compounds 2, 3, 5–7, and 10 have been determined by X-ray crystallography. The redox properties of FcLnH and their compounds 1–10 were also investigated by cyclic voltammetry. In vitro cytotoxic activities of compounds 1–4, ...

The self-assembly of tetrabutyldistannoxane ladder {[nBu2Sn(LH)]2O}2 1 upon crystallization in xylene affords the novel cyclic dimer [nBu(LxH)Sn]2 2, featuring a 22-membered macrocycle. The dimer also contains a 2-fold linkage of neighbouring units via intermolecular Sn-O contacts, giving rise to polymeric 1D chains in which the tin atoms assume pentagonal bipyramidal environments by means of additional Sn-Ocatecholate contacts.

Oxidative insertion of low valent tellurium, Te(0) and Te(II), into the C Br bond of α-bromoacetylpiperidine proceeds readily under mild conditions and provides a direct synthetic route to stable, crystalline piperidin-1-ylamidomethyltellurium(IV) dibromides, (C5H10NCOCH2)2TeBr2, 1b and (C5H10NCOCH2)ArTeBr2 (Ar = 2,4,6-Me3C6H2, 2b; 1-C10H7, 3b; 4-MeC6H4, 4b). While the bisulfite reduction of 1b affords a yellow coloured telluroether, (C5H10NCOCH2)2Te, 1 as an oil, that of the unsymmetrical diorganotellurium dibromides, (C5H10NCOCH2)ArTeBr2 leads to the isolation of the respective diarylditellurides, ArTeTeAr. The symmetrical telluroether, 1 adds dihalogens oxidatively to give piperidin-1-ylamidomethyltellurium(IV) dihalides, (C5H10NCOCH2)2TeX2 (X = Cl, 1a; Br, 1b and I, 1c;). All the new piperidin-1-ylamidomethyltellurium derivatives have been characterized by elemental and 1H, 13C, 125Te NMR spectral analyses. Single-crystal X-ray diffraction data for 1b and 1c indicated a butterfly molecular shape for the two halo analogues in which the six-member heterocyclic rings in the organic ligands retain the chair conformation of the independent piperidine molecule. The piperidin-1-yl appended organic ligand invariably results in the amido O atom being involved in an intramolecular Te O secondary bonding interaction and acts as a small-bite (C, O) chelating agent, at least in the solid state. Steric congestion around the six-coordinate Te(IV) atom and the partial positive charge on N owing to the resonating character of the N C O amido group prevents these atoms from participating in the intermolecular associative forces. Instead, the weak C H⋯O and C H⋯Br interactions take centre-stage in the solid state self-assembly.

Reaction of sodium 2-((E)-((Z)-4-hydroxypent-3-en-2-ylidene)amino)succinate and sodium (E)-2-((1-(2-hydroxyphenyl)ethylidene)amino)succinate (L1HNa2 and L2HNa2) in a 1:2 M ratio with Bz2SnCl2 in methanol gave dinuclear diorganotin(IV) complexes of composition [Bz2Sn(Lx)SnBz2Cl] (Lx = L1 (1) and L2 (2)). Reaction of L2HNa2 and Bz3SnCl (1:2) in anhydrous toluene under reflux conditions yielded the analogous chlorine-free product of composition [Bz2Sn(L2)SnBz3] (3) via cleavage of a Sn-C bond for one of the triorganotin precursor equivalents with elimination of toluene. In addition, the tributyltin(IV) compounds of composition [Bu3Sn(LxH)SnBu3] (Lx = L2 (4) and L3 (5)) were prepared in a single-step transformation by combining equimolar proportions of (Bu3Sn)2O, (S)-2-aminosuccinic acid and 2'-hydroxyacetophenone/2-hydroxybenzaldehyde in anhydrous methanol. The structures of the organotin(IV) compounds in solution were assessed using 1H, 13C and 119Sn NMR spectroscopic techniques, while the molecular structures of 1–5 were analyzed by single-crystal X-ray diffraction. In the solid state, complexes 1-3 exhibit one-dimensional coordination polymers with alternate six- and seven-coordinate tin atoms embedded in distorted monocapped trigonal-bipyramidal (1-2)/octahedral (3) and pentagonal-bipyramidal (1-2)/bicapped trigonal-bipyramidal (3) coordination environments. On the contrary, compounds 4–5 are two-dimensional coordination polymers based on 30-membered tetranuclear macrocyclic ring structures, in which the tin atoms comprise distorted trigonal-bipyramidal coordination polyhedra. However, in solution the polymeric structures of 1–5 dissociate to give dinuclear complexes, even in non-coordinating solvents such as chloroform.

Five new organotin(IV) complexes of compositions [Me 2 SnL 1 ] ( 1 ), [Me 2 SnL 2 ] n ( 2 ), [Me 2 SnL 3 ] ( 3 ), [Ph 3 SnL 1 H] n ( 4 ) and [Ph 3 SnL 3 H] ( 5 ) (where L 1 = (2 S )-2-(( E )-(( Z )-4-hydroxypent-3-en-2-ylidene)amino)-3-(1 H -indol-3-yl)propanoate, L 2 = (2 S )-( E )-2-((2-hydroxybenzylidene)amino)-3-(1 H -indol-3-yl)propanoate and L 3 = (2 S )-( E )-2-((1-(2-hydroxyphenyl)ethylidene)amino)-3-(1 H -indol-3-yl)propanoate were synthesized and spectroscopically characterized. The crystal structures of 1 – 4 were determined. For the dimethyltin derivative 2 , a polymeric chain structure was observed as a result of a long Sn∙∙∙O contact involving the exocyclic carbonyl oxygen-atom from the tridentate ligand of a neighboring Sn-complex unit. The tin atom in this complex has a distorted octahedral coordination geometry, in which the long Sn-O bond is almost trans to the tridentate ligand nitrogen-atom. In contrast, the dimethyltin(IV) complexes 1 and 3 displayed discrete monomeric structures where the tin atom has distorted trigonal-bipyramidal geometry with the two coordinating L oxygen atoms defining the axial positions. On the other hand, 4 is a chain polymer in the solid state. The ligand-bridged Sn atoms adopt a trans -Ph 3 SnO 2 trigonal-bipyramidal configuration with equatorial phenyl groups. A carboxylato oxygen atom from one and the hydroxyl oxygen of the successive ligand in the chain occupy the axial positions. The solution structures were predicted by the use of 119 Sn NMR chemical shifts. The photophysical properties of the complexes were investigated in the solid and in solution. The triphenyltin(IV) compound 4 was tested in detail ex vivo against A375 (human melanoma) cell line, exhibiting an IC 50 value of 261 nM to induce cell death as assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay without significant alteration of cytolysis as determined by lactate dehydrogenase (LDH) assay. Compound 4 -mediated potent cell death was also determined by Live and Dead assay and caspase-mediated cleavage of poly-ADP ribose polymerase (PARP). Potent cell death activity was not observed in primary cells, like blood-derived peripheral mononuclear cells (PBMC). Compound 4 inhibited the diphenyl hexatriene (DPH) binding to cells and decreased the micro viscosity in a dose-dependent manner. Additionally, the ability of 4 and cyclodextrin (CD) to interact was determined by molecular modelling.

Six new bicycloazastannoxides of compositions [Me2Sn(L1H)] (1), [nBu2Sn(L1H)] (2), [Ph2Sn(L1H)] (3), [Bz2Sn(L1H)] (4), [Me2Sn(L2H)(MeOH)]·MeOH (5) and [Ph2Sn(L3H)] (6), where L1H = 2-((E)-((Z)-4-hydroxypent-3-en-2-ylidene)amino)-3-(4-hydroxyphenyl)propanoate, L2H = (E)-2-((2-hydroxybenzylidene)amino)-3-(4-hydroxyphenyl)propanoate and L3H = (E)-3-(4-hydroxyphenyl)-2-((1-(2-hydroxyphenyl)ethylidene)amino)propanoate, were synthesized and spectroscopically characterized. The 1H and 13C NMR spectra of compounds 1–6 displayed two sets of signals for Sn-R2 (R = Me, nBu, Ph and Bz) indicating a diastereotopic environment according to the asymmetric nature of the ligand. The 119Sn NMR data of the compounds in CDCl3 indicate five-coordinate tin atoms, showing that the bicycloazastannoxide assemblies remain intact as observed in the solid-state structures. The crystal structures of 1–6 revealed discrete molecular structures in all cases with distorted trigonal-bipyramidal geometries for 1–4 and 6, and a strongly distorted six-fold coordination for 5 due to association of a MeOH solvent molecule. At the supramolecular level, the molecular structures in 1–4 and 6 are linked either through double-bridged O-H⋯O/C-H⋯O synthons (1 and 6) or single O-H⋯O hydrogen bonds (2–4). The resulting 1D helical strands exhibit varying Sn⋯Sn distances due to the different molecular conformations. The molecules in 5 associate to dimers through two Sn⋯O and O-H⋯O interactions, which are further connected via O-H⋯O hydrogen bonds to give 1D strands containing 22-membered macrocycles.

By reacting 2- and 3-aminobenzoic acids (HL1 and HL2, respectively), as well as 2-, 3- and 4-{(E)-2-[4-(dimethylamino)phenyl]diazenyl}benzoic acids (HL3, HL4 and HL5, in this order) with a n-butyltin(IV) source [nBuSn(O)OH or nBu2SnO], the drum-type butylstannoxane complexes of general composition [nBu6Sn6O6(Ln)6] [Ln = L1 (1), L2 (2) and L3 (3)] and the ladder-type compounds [nBu8Sn4O2(Ln)4] [Ln = L3 (5), L4 (6) and L5 (7)] were obtained and fully characterized. By reacting 1 with 2-{(E)-[4-(dimethylamino)benzylidene]amino}benzoic acid (HL6), a co-crystal (4) was achieved which comprises the metal complex aggregate found in 1 and the neutral HL6 molecule. The solution properties of the compounds were assessed from 1H and 13C NMR studies and, for the metal complexes, also from 119Sn NMR. The molecular structures of 1, 2, 4–7 were confirmed by single-crystal X-ray diffraction. Compounds 1–3 and the complex moiety of 4 display hexameric Sn6O6 clusters with drum-like structures, but 5–7 reveal Sn4O2 cores with ladder-type structural motifs. Besides the observed relationship between the ligand N-functional group and obtained (drum- or ladder-type) assemblies, the relative position of the carboxylate group in the ligand itself influences its coplanarity.

A series of diamondoid-decorated organotin(IV) derivatives of composition Me3Sn(L1) (1), Ph3Sn(L1) (2), {[Me2Sn(L1)]2O}2 (3), [BzSn(O)(L1)]6 (4), Me3Sn(L2)OH2 (5), [Ph3Sn(L2)]n (6), Bu2Sn(L2)2 (7), Bz2Sn(L2)2OH2 (8) and [BzSn(O)(L2)]6 (9) were prepared by reacting appropriate organotin(IV) precursors with either acid forms of the pro-ligands adamantane-1-carboxylic acid (HL1) and 2-(adamantan-1-yl)acetic acid (HL2) or their sodium salts. Compounds 1–9 were characterised by spectroscopic techniques, including 119Sn NMR in non-coordinating solvent for assessment of the solution-state structures. The molecular and crystal structures of 2–8 were established by X-ray crystallography. The packing is largely dictated by hydrophobic interactions with the exception in the crystals of 6, where Sn…O secondary bonding is apparent, and in each of 5 and 8 where O–H…O hydrogen bonding is present leading to a two-dimensional array and zig-zag chains, respectively. The organotin compounds were evaluated for their anti-bacterial activity against 15 human bacterial pathogens. Based on disc diffusion and minimum inhibitory concentration assays, the two triphenyltin species, 2 and 6, and di-n-butyl species, 7, are effective against both Gram-positive and Gram-negative bacteria, including methicillin resistant Staphylococcus aureus (MTCC 381123) and Shigella flexneri (ATCC 12022), a causative agent for shigellosis. Time-kill assays showed that 2 and 6 had both time- and concentration-dependant anti-bacterial effects against susceptible bacteria. Cell viability assays showed that 2 and 6 were moderately toxic to a normal cell line, that is, human embryonic kidney 293T (HEK293T).

Reactions of carbamodithiolate salts viz., c-C3H5NH3+(L1)− and c-C6H11NH3+(L2)− (L1 = cyclopropylcarbamodithioate, L2 = cyclohexylcarbamodithioate) with R2SnCl2 (R = Me or n-Bu) were investigated in dichloromethane for the first time. A series of four diorganotin(IV) complexes of composition [Me2Sn(L1)Cl] (1), [Me2Sn(L1)2] (2), [Me2Sn(L2)2] (3) and [n-Bu2Sn(L2)2] (4) were isolated and characterized by spectroscopic methods. The structures of the two carbamodithiolate salts and the diorganotin(IV) compounds 1-4 were accomplished by X-ray crystallographic analysis revealing distorted square pyramid geometry for 1, but skewed trapezoidal bipyramids for 2-4. Influence of the carbamodithiolate moiety on the hydrogen-bond interactions and non-covalent contacts, as well as on the packing of the structures, is discussed. The 3D Hirshfeld surfaces were mapped and used to study the intermolecular interactions.

Metal complexes with organelle specificity and potent but selective cytotoxicity are highly desirable. A novel series of triphenylstannyl 4-((arylimino)methyl)benzoates (2-8) were obtained by the reactions of triphenylstannyl 4-formylbenzoate [Ph3Sn(L1)] 1 with primary aromatic amines. Two representative compounds (10, 11) were also synthesized by reacting aqua-triphenylstannyl 2-formylbenzoate [Ph3Sn(L9)(H2O)] (9) with aniline and p-fluoroaniline, respectively. These compounds were characterized by elemental analysis, IR and 1H, 13C and 119Sn NMR spectroscopy, as well as single-crystal X-ray diffraction for compounds 5, 7-11 and three pro-ligands. The in vitro cytotoxic activities of 1-11 were assessed using the MTT tetrazolium dye assay against HeLa (human cervical) and MDA-MB-231 (breast) cancer cells, with IC50 values revealing high activity. Compared to cisplatin, compounds 1-11 exhibited enhanced cytotoxic efficacy, indicating their potential as potent anticancer agents. Among these, 1 and 5 demonstrated maximum inhibition in HeLa cells, with negligible effect on normal human embryonic kidney (HEK) cells. The combined results of the DCFH-DA dye and Hoechst 33342/PI nuclear staining assays, along with flow cytometry analysis, show that they possess a dual mode of action: They induced apoptotic cell death, attributable to the tin-assisted generation of reactive oxygen species. Cell cycle analyses indicated that compounds 1 and 5 exhibit cell growth inhibition and may cause turbulences in the G1 and G2/M phases.

It has been our endeavor to prepare organotellurium compounds bearing functionalized groups. The electrophilic substitution reactions were performed with 1-acetyl-1-cyclohexene, an alkenylmethyl ketone (cyclo-C6H9COCH3), with NpTeCl3 and MesTeCl3. The reactions were found to proceed smoothly at room temperature. The unsymmetrical functionalized arylalkyltellurium dichloride Np(cyclo-C6H9COCH2)TeCl2, 1Aa or Mes(cyclo-C6H9COCH2)TeCl2, 1Ba was obtained in good to moderate yield when the reactants were stirred for 7-8 h in absence of any solvent. The reaction with MesTeCl3 is rather slow and requires over 24 h of stirring. Biphasic (H2O/CH2Cl2) reduction of the dichlorides 1Aa or 1Ba with aqueous Na2S2O5 did not gave the expected unsymmetrical telluroether (cyclo-C6H9COCH2)-Te-Ar, instead the usual work up of the organic phase afforded the respective ditellurides, Ar2Te2. The bromo analogues of 1Aa and 1Ba, namely Ar(cyclo-C6H9COCH2)TeBr2 (Ar= 1-Np, 1Ab and Mes, 1Bb), were prepared by the metathetical reaction of the chlorides with sodium bromide (Scheme 1). The newly synthesized dihaloaryltellurated alkenyl carbonyl compounds are colourless to pale yellow crystalline solids soluble in common organic solvents and have been characterized by 1H, 13C and 125Te NMR in solution. The structural studies in the solid state for the compounds 1Aa and 1Ba have been carried out by single-crystal X-ray diffraction technique

The novel phosphonyl-substituted ferrocene derivatives [Fe(η(5) -Cp)(η(5) -C5 H3 {P(O)(O-iPr)2 }2 -1,2)] (Fc(1,2) ) and [Fe{η(5) -C5 H4 P(O)(O-iPr)2 }2 ] (Fc(1,1') ) react with SnCl2 , SnCl4 , and SnPh2 Cl2 , giving the corresponding complexes [(Fc(1,2) )2 SnCl][SnCl3 ] (1), [{(Fc(1,1') )SnCl2 }n ] (2), [(Fc(1,1') )SnCl4 ] (3), [{(Fc(1,1') )SnPh2 Cl2 }n ] (4), and [(Fc(1,2) )SnCl4 ] (5), respectively. The compounds are characterized by elemental analyses, (1) H, (13) C, (31) P, (119) Sn NMR and IR spectroscopy, (31) P and (119) Sn CP-MAS NMR spectroscopy, cyclovoltammetry, electrospray ionization mass spectrometry, and single-crystal as well as powder X-ray diffraction analyses. The experimental work is accompanied by DFT calculations, which help to shed light on the origin for the different reaction behavior of Fc(1,1') and Fc(1,2) towards tin(II) chloride.

The reaction of tellurium tetrahalides, TeX4 (X Cl. Br) with acetyltrimethylsilane in CCl4 at ambient temperature, unlike that of the aryltellurium trichlorides, ArTeCl3 that give the expected electrophilic substitution products, Ar(Me3SiCOCH2)TeCl2, (Ar = 1-C10H7, 2; 2,4,6-Me3C6H2, 3), afforded novel silylated heterocycles, 3-methyl-5-(trimethylsilyl)-1,2-oxatellurol-1-ium halides 1a and 1b. These Te(II) heterocyclic compounds undergo halide exchange with sodium iodide and also add dihalogens oxidatively to afford the corresponding iodide, 1c and the Te(IV) trihalides, 5a and 5b respectively. A large lowering of ν(CO) is indicative of strong Te⋯O C interactions among these heterocycles, and is also substantiated by single-crystal X-ray diffraction data for 3-methyl-5-(trimethylsilyl)-1,2-oxatellurol-1-ium chloride. The 125Te chemical shifts for the new 10-Te-3 telluranes and 12-Te-5 pertelluranes that involve tellurium bound to two highly electronegative atoms (O, X) are among the highest (downfield) reported for organotellurium(II) and (IV) compounds.

Synthesis and complete characterization of some ester functionalized vinylic tellurides bearing an aryl ligand with varying steric and electronic effects bound to tellurium is described. Hydrotelluration of methyl propiolate using Ar2Te2/NaBH4 in methanol results in a mixture of stereoisomers of methyl β-(aryltelluro)acrylates, ArTeCHCHCOOMe (Ar = 4-MeOC6H4, 1A; 1-C10H7, 2A; 2,4,6-Me3C6H2, 3A; C5H5FeC5H4, 4A; 4-Me2NC6H4, 5A; and 2-C4H3S, 6A). The same reaction in ethanol provides isomeric mixtures of the ethyl esters ArTeCHCHCOOEt (1B–6B). However, in the reactions between methyl propiolate and Ar2Te2 (Ar = 2,4,6-Me3C6H2, 4-Me2NC6H4) in isopropanol or t-butanol, no exchange of alkyl groups between the parent ester and the solvent is observed, instead detelluration of the Ar2Te2 to Ar2Te is a competing reaction along with almost exclusive formation of the (Z)-isomers (3Aa, 5Aa). The geometry of the separated stereoisomers is established in solution, with the help of 1H, 13C and 125Te NMR spectrometry. Of particular interest is the observation that 125Te chemical shifts {deshielded in (Z) compared to (E); Δδ = 106–136 ppm} and the geminal heteronuclear coupling constants {2J(1H–125Te) values for (E) are more than seven times that of the corresponding (Z) isomer} can be used to distinguish between liquid isomers. Structural characterization in the solid state by single-crystal X-ray diffraction for the 2Ba, 3Aa, 3Ba, 5Aa, 8 (Z)-isomers as well as for both stereoisomers of 4-Me2NC6H4TeCHCHCOOEt (5Ba and 5Bb) is also presented. The carbonyl O atom of the ester group is invariably involved, at least in the solid state, in a secondary bonding interaction with the Te(II) atom. While an intermolecular Te⋯O interaction gives rise to one-dimensional supramolecular arrays in the crystal lattice of 5Bb with (E) configuration, it is realized intramolecularly in the case of the (Z)-isomers due to the cis position of the chalcogen atoms.

Chlorination of bis(1-naphthyl)ditelluride (NplTeTeNpl; Npl = 1-C10H7) with 3 equiv. of sulfuryl chloride (SO2Cl2) resulted in bright yellow crystals of 1-naphthyltellurium(IV) trichloride (1-NplTeCl3; 1). Bis(mesityl)tellurium(IV) dichloride, Mes2TeCl2, 2 (Mes = 2,4,6-Me3C6H2) has been synthesized by the oxidative addition of sulfuryl chloride to bis(mesityl)telluride(II), prepared from detelluration of bis(mesityl)ditelluride with a freshly prepared electrolytic copper. Bis(chlorobis(2-thiophenyl)tellurium)oxide, (Tpn2TeCl)2O, 3 (Tpn = 2-C4H3S) have been obtained serendipitously as a product of reaction between bis(thiophenyl)tellurium(IV) dichloride (Tpn2TeCl2) and AgCN. All the three compounds 1–3 have been characterized crystallographically. In crystal lattice of 1, an asymmetric unit consists of two independent molecules and both the molecules form a separate polymeric zig-zag chains via μ2-chloro bridging. These two polymeric chains are interlinked via C−H⋯Cl H-bonding interactions to form a one dimensional supramolecular array. In case of 2 a dimeric unit has been realized through C−H⋯Cl H-bonding interaction while in 3 a one dimensional supramolecular array has been formed via intermolecular Te⋯Cl1 secondary bonding interactions, where both the tellurium atoms exhibit ψ-trigonal bipyramidal geometry.

Five new diorganotin(IV) compounds were prepared by reacting diorganotin dichlorides R 2 SnCl 2 (R = Me, n Bu and Ph) with sodium salts of the tridentate NO 2 ligands ( E )-3-hydroxy-2-((2-hydroxybenzylidene)amino)propanoic acid (L 1 H 2 Na) and ( E )-3-hydroxy-2-((1-(2-hydroxyphenyl)ethylidene)amino)propanoic acid (L 2 H 2 Na). The molecular structures of the resulting diorganotin (IV) compounds have been established by elemental analysis and a combination of IR and NMR ( 1 H, 13 C, 119 Sn) spectroscopy. In all cases, the 119 Sn NMR chemical shifts were indicative of five-coordinate tin atoms in solution. However, investigation of compounds [Me 2 SnL 1 H]·H 2 O ( 1 ), [Ph 2 SnL 1 H]·2C 6 H 6 ( 3 ), [Me 2 SnL 2 H]·CHCl 3 ( 4 ) and [Ph 2 SnL 2 H] ( 5 ) by single-crystal X-ray diffraction revealed that only compound 3 has a distorted trigonal–bipyramidal geometry in the solid state. For compounds 1 , 4 and 5 the coordination geometries are distorted octahedral, either due to intermolecular association through Sn⋯O interactions ( 1 ) or coordination through the oxygen atom from the pendant CH 2 OH group ( 4 and 5 ). At the supramolecular level, the molecular structures are linked through O–H⋯O hydrogen bonds to give discrete dimeric assemblies ( 4 ), 1D chains ( 3 , 5 ) and 2D hydrogen bonded layers ( 1 ).

Chloro analogs of novel organotellurium(IV) compounds (1a, 2Aa, 2Ba, 3Aa & 3Ba) have been synthesized by using electrophilic substitution reactions. The 2-pyridoylmethyltellurium(IV) trichloride, PyCOCH2TeCl3; 1a (Py = 2-C5H4N, 1) has been prepared by the condensation reaction between the parent methyl ketone (PyCOCH3) and TeCl4. Aryl(2-pyrrolylmethyl)tellurium(IV) dichlorides, Ar(PyrrCOCH2)TeCl2; 2Aa, 2Ba (Pyrr = 2-C4H4N, 2; Ar = 1-C10H7, Npl, A; 2,4,6-Me3C6H2, Mes, B) and aryl(2-oxocyclohexyl)tellurium(IV) dichlorides, Ar(Cyl)TeCl2; 3Aa, 3Ba (Cyl = 2-C6H9O, 3) have been prepared by electrophilic substitution reaction of NplTeCl3 or MesTeCl3 with 2-acetylpyrrole and cyclohexanone respectively. Formation of tellurium(IV) trichloride (PyCOCH2TeCl3, 1a) corresponds to a category of compound which are rarely obtained using this methodology. Structural aspects of Te(IV) compounds 1a, 2Ba and 3Ba have been studied using single crystal X-ray diffraction technique. Crystallographic studies of 1a has indicated a preference of the 2-pyridoylmethyl moiety for the small-bite (C, N) chelation resulting in the 1,5 Te⋯N hypervalent interaction while in PyrrCOCH2MesTeCl2, 2Ba; 2-pyrrolylmethyl moiety (C, O) chelation over less strained (C, N) coordination is preferred. In 3Ba, 1,4 Te⋯O intramolecular secondary bonding interaction (SBI) has appeared.

Two novel indium(III) phosphonates, [In2(t-BuPO3H)4(phen)2Cl2] (1) and [In3(C5H9PO3)2(C5H9PO3H)4(phen)3]·NO3·3.5H2O (2) with phen = 1,10-phenanthroline, have been synthesized by solvothermal reactions involving indium(III) salts and organophosphonic acids. 1 is a dinuclear compound where the two indium centers are bridged by a pair of isobidentate phosphonate ligands, [t-BuP(O)2OH]−, resulting in an eight-membered (In2P2O4) puckered ring. Compound 2 is trinuclear; the In3 platform is held together by two bicapping tripodal phosphonate ligands from the top and bottom of the indium plane. In addition, two bridging monoanionic phosphonate ligands serve to bind two pairs of indium centers. Both 1 and 2 also contain monodentate monoanionic phosphonate ligands. The solid-state MAS 31P NMR spectrum of complex 1 shows two signals at 21.9 and 29.3 ppm. Compound 2 contains signal maxima at 25.8 and 28.9 ppm, with a shoulder at 31.5 ppm. Room temperature solid-state fluorescence spectra of 1 and 2 are characterized ...

Oxidative addition of α-bromo-3-acetyl-2,5-dimethylthiophene to elemental tellurium and aryltellurium(II) bromide provides direct routes to (2,5-dimethyl-3-thiophenoylmethyl)tellurium(IV) dibromides, (Me2TpnCOCH2)2TeBr2 (1a; Me2Tpn = 2,5-Me2-3-C4HS) and Ar(Me2TpnCOCH2)TeBr2 (Ar = 1-C10H7, Npl, 2a; 2,4,6-Me3C6H2, Mes, 3a). The chloro analogs of 2a and 3a, Ar(Me2TpnCOCH2)TeCl2 (Ar = Npl, 2b; Mes, 3b) and derivative when Ar = Anisyl (anisyl = 4-MeOC6H4, 4b) were prepared by the condensation reaction of methyl ketone, Me2TpnCOCH3 with NplTeCl3, MesTeCl3 and anisylTeCl3 respectively while the chloro analog of 1a, bis(2,5-dimethyl-3-thiophenoylmethyl)tellurium(IV) dichloride, (Me2TpnCOCH2)2TeCl2 (1b) was obtained by the condensation reaction of methyl ketone, Me2TpnCOCH3 with TeCl4. Metathesis of these products (1a–b, 2a–b, 3a–b and 4b) with an alkali iodide affords the iodo analogs 1c, 2c, 3c and 4c. These diorganotellurium dihalides are reduced with aqueous bisulfite to diorganotellurides 1–4, which can be oxidized readily with dihalogens to the desired diorganotellurium(IV) dihalides. The crystal structures of the Te(IV) compounds 1b, 2a, 3c and 4b have been studied and all the Te(IV) compounds, the carbonyl functionalized organic moiety, show intramolecular 1,4–Te⋯O secondary bonding interaction (SBI). In the crystal lattice of 2a, the intermolecular Te⋯Br secondary bonding interactions are evident and result in a dimer. They get further associated via C–H⋯Br secondary interactions to form a 3D supramolecular motifs. In 1b, 3c and 4b supramolecular motifs are formed through C–H⋯O and C–H⋯Cl interactions.

Methyl and t-butyl esters of α-bromoacetic acid added oxidatively to elemental tellurium in the presence of sodium iodide to give high yields of crystalline bis(alkoxycarbonylmethyl)tellurium(IV) diiodides, (ROCOCH2)2TeI2. The chloro and bromo analogs were prepared via their reduction into tellurides followed by dihalogen oxidation. Activation of the α-Csp3–Br bond by ester functionality appears to be insufficient as methyl α-bromoacetate failed to add to Te(0) or aryltellurium(II) bromides. The nucleophilic substitution reaction of α-bromoesters with aryltellurolates, ArTe−Na+ (Ar = 1-C10H7, Np; 2,4,6-Me3C6H2, Mes), gave (alkoxycarbonylmethyl)aryltellurides that were characterized as mixed diorganotellurium dihalides. Crystal structures of Np(MeOCOCH2)TeBr2, Mes(MeOCOCH2)TeBr2 and Mes(t-BuOCOCH2)TeCl2 show that the functionalized organic moiety, ROCOCH2, behaves as a (C, O) chelating ligand. The carbonyl O atom of the ester group in these compounds is involved in a 1,4-Te⋯O secondary bonding interaction. However, the functionalized ligands in the case of (MeOCOCH2)2TeI2 are devoid of such an interaction. Surprisingly, one of the two organic ligands in (MeOCOCH2)2TeBr2 takes part in an intramolecular 1,4-Te⋯O interaction, the other appears to involve an intermolecular Te⋯O interaction to result in a one-dimensional array of molecules in the crystal lattice.

Synthesis and spectroscopic properties of seven new dibutyltin(IV) compounds of 2-{(E)-4-hydroxy-3-[(E)-4-(aryl)iminomethyl]phenyldiazenyl}benzoic acids (LnHH'; n=2-8) with general formula {[Bu2Sn(LnH)]2O}2 (1-7) are reported. The compounds were characterized by elemental analysis and by UV-Visible, fluorescence, IR, 1H, 13C and 119Sn NMR spectroscopies. Solid state structures of dibutyltin(IV) compounds 1-3, 6 and 7 were accomplished from single crystal X-ray crystallography which reveal the common ladder-type structure with two endo- and two exo-Sn atoms. The redox properties of LnHH' (n=2-4, 7 and 8) and their diorganotin(IV) compounds 1-3, 6 and 7 were also investigated by cyclic voltammetry. In general, the dibutyltin(IV) derivatives exhibited significant in vitro cytotoxic potency towards A375 (melanoma) and HCT116 (colon carcinoma) cell lines as determined by several experiments, like Live and Dead assay, MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) cell viability assay, LDH (lactate dehydrogenase), cleavage of caspases and PARP (poly(ADP-ribose)polymerase), and DNA fragmentation. Dibutyltin(IV) compounds increase cell death without cytolysis and decreases membrane fluidity, without interfering with p53. Among the dibutyltin(IV) compounds, compound 6 was found to be the most potent, with an IC50 value of 78nM. A mechanism of action for tumor cell death is proposed.

The title compound (Cp*Sn)BPh 4 was obtained by the metathesis reaction of Cp*SnCl with NaBPh 4 and characterized by single crystal X-ray diffraction as well as solution and solid-state 119 Sn nuclear magnetic resonance (NMR) spectroscopy. The coordination modes are best described as ( η 5 -C 5 Me 5 )Sn( μ - η 6 -Ph) 2 BPh 2 .

The fi rst series of building blocks for metal-organic frameworks (MOFs) utilizing the ( S )-2,2 ′ -diethoxy-1,1 ′ binaphthyl-6,6 ′ -dicarboxylic acid ligand linked with a number of α , ω -bis(chlorodiorganostannyl) alkane spacers and α , ω -bis(dichloroorganostannyl) alkane spacers has been synthesized and characterized. The new compounds have been shown to form monomeric chiral rings with the potential to generate large coordination networks. The potential formation of chiral supramolecular and polymeric materials from the chiral precursors was explored by investigating the structures that form as a result of the hypervalency available at metal centers. These chiral compounds were built using the concept that stemmed from the construction of MOFs. The ‘ pre-organized ’ chiral rings synthesized here can potentially fi nd use in chiral catalysis, enantioselective synthesis and in designing chiral polymers.

Chlorotelluration of terminal acetylenes, RCH CH ( R = Ph, 1 ; 4-MeC 6 H 4 , 2 ; t -Bu, 3 ) with aryltellurium trichlorides and TeCl 4 in refluxing toluene affords (2-chloro-2-organylvinyl)tellurium(IV) dichlorides, Ar[R(Cl)C CH]TeCl 2 (Ar = 1-C 10 H 7 , 1Aa – 3Aa ; 2,4,6-Me 3 C 6 H 2 , 1Ba–3Ba ; 4-MeOC 6 H 4 , 1Ca ) and [ t -Bu(Cl)C CH] 2 TeCl 2 , 3a respectively. These Te(IV) derivatives on reduction with Na 2 S 2 O 5 give the corresponding vinyltellurides as oils, except (2,4,6-Me 3 C 6 H 2 )[Ph(Cl)C CH]Te ( 1B ) which is a crystalline solid. The dibromides ( 1Ab – 3Ab , 1Bb – 3Bb , 3b ) and diiodides ( 1Ac – 3Ac , 1Bc – 3Bc , 1Cc ) were obtained by the oxidative addition of dihalogens to the tellurides. The stereochemistry of the products has been established with the help of X-ray diffraction studies of 1Aa , 1Ba , 1Bc , 1Cc , 3Aa , 3a and 1B . Intramolecular Te⋯Cl attractive interactions appear to favor the ( Z ) conformation adopted by the 2-chloro-2-organylvinyltellurium group irrespective of the steric demand of the aryl ligand of the Te(IV) electrophile and the terminal acetylene substituent. The intermolecular Te⋯X secondary bonding interactions give rise to dimeric units in the lattices of 1-naphthyl- and anisyltellurium(IV) derivatives, but are absent among the mesityl analogues, consistent with the larger steric requirement of the latter ligand.

The stepwise reaction of [2,6-Mes2C6H3In(OH)2]4 with carbon dioxide and ethylene glycol proceeded with the formation of (2,6-Mes2C6H3In)4(CO3)2(OH)4(H2O)2 (1) and (2,6-Mes2C6H3In)4(OCH2CH2O)2(OH)4 (2), respectively, and eventually produced (2,6-Mes2C6H3In)4(CO3)2(OCH2CH2OH)2(OH)2 (3). Attempts to liberate ethylene carbonate upon heating of 3 were unsuccessful.

Depolymerization of the aryltellurinic anhydrides [(RTe)2O3]n (9, R = 4-MeOC6H4; 6, R = 8-Me2NC10H6) with aqueous NaOH afforded the hydrated sodium aryltellurinates [Na(H2O)4](4-MeOC6H4TeO2) (10) and [Na(H2O)4](8-Me2NC10H6TeO2)·H2O (11·H2O) as highly crystalline materials.

Four new triphenyltin(IV) complexes of composition Ph 3SnLH (where LH = 2-/4-[(E)-2-(aryl)-1-diazenyl]benzoate) (1-4) were synthesized and characterized by spectroscopic ( 1H, 13C and 119Sn NMR, IR, 119Sn Mössbauer) techniques in combination with elemental analysis. The 119Sn NMR spectroscopic data indicate a tetrahedral coordination geometry in non-coordinating solvents. The crystal structures of three complexes, Ph 3SnL 1H (1), Ph 3SnL 3H (3), Ph 3SnL 4H (4), were determined. All display an essentially tetrahedral geometry with angles ranging from 93.50(8) to 124.5(2)°; 119Sn Mössbauer spectral data support this assignment. The cytotoxicity studies were performed with complexes 1-4, along with a previously reported complex (5) in vitro across a panel of human tumor cell lines viz., A498, EVSA-T, H226, IGROV, M19 MEL, MCF-7 and WIDR. The screening results were compared with the results from other related triphenyltin(IV) complexes (6-7) and tributyltin(IV) complexes (8-11) having 2-/4-[(E)-2-(aryl)-1-diazenyl]benzoates framework. In general, the complexes exhibit stronger cytotoxic activity. The results obtained for 1-3 are also comparable to those of its o-analogs i.e. 4-7, except 5, but the advantage is the former set of complexes demonstrated two folds more cytotoxic activity for the cell line MCF-7 with ID 50 values in the range 41-53 ng/ml. Undoubtedly, the cytotoxic results of complexes 1-3 are far superior to CDDP, 5-FU and ETO, and related tributyltin(IV) complexes 8-11. The quantitative structure-activity relationship (QSAR) studies for the cytotoxicity of triphenyltin(IV) complexes 1-7 and tributyltin(IV) complexes 8-11 is also discussed against a panel of human tumor cell lines. © 2011 Elsevier Inc. All rights reserved.

The reaction of 8-dimethylaminonaphthyllithium etherate with the tellurium(II) bis(dithiocarbamate) Te(S2CNEt2)2 provided the diaryltelluride (8-Me2NC10H6)2Te (1). The oxidation of 1 with an excess of H2O2 did not afford the expected diaryltellurium(IV) oxide (8-Me2NC10H6)2TeO (2), but the diaryltellurium(VI) dioxide (8-Me2NC10H6)2TeO2 (3). The preparation of 2 was achieved by the comproportionation reaction of 1 and 3. The protonation of 2 using triflic acid gave rise to the formation of diarylhydroxytelluronium triflate [(8-Me2NC10H6)2Te(OH)](O3SCF3) (4), which features the protonated diaryltellurium oxide [(8-Me2NC10H6)2Te(OH)]+ (4a). Compounds 1, 3·H2O·H2O2, 3·2H2O, and 4 were characterized by X-ray crystallography. The experimentally obtained molecular structures were compared to those calculated for 1–3, 4a, and (8-Me2NC10H6)2Te(OH)2 (5) as well as the related diphenyltellurium compounds Ph2Te (6), Ph2TeO (7), Ph2TeO2 (8), [Ph2Te(OH)]+ (9a), and Ph2Te(OH)2 (10) at the DFT/B3PW91 level of theory.

α-Bromo-2-acetylfuran adds oxidatively to elemental tellurium and aryltellurium(II) bromide at ambient temperature to afford (2-furoylmethyl)tellurium(IV) dibromides, (FuCOCH2)2TeBr2 (1b) and Ar(FuCOCH2)TeBr2 (Fu = 2-C4H3O; Ar = 1-C10H7, 2b; 2,4,6-Me3C6H2, 3b). The iodo analogues 1c–3c can be obtained by metathesis of the bromides with an alkali iodide. Condensation reactions of the parent methyl ketone with Te(IV) chlorides results in the corresponding chloro analogues, (FuCOCH2)2TeCl2 (1a) and Ar(FuCOCH2)TeCl2 (2a, 3a and Ar = 4-MeOC6H4 (4a)). These diorganotellurium dihalides are reduced with aqueous bisulfite to diorganotellurides 1–3, which can be oxidized readily with dihalogens to the desired diorganotellurium(IV) dihalides. The tellurated furan derivative, bis(2-furyl)tellurium(II), Fu2Te (5), obtained by detelluration of bis(2-furyl)ditelluride with electrolytic copper, gives crystalline bis(2-furyl)tellurium(IV) dichloride (5a) upon chlorination. Crystal structures of Te(IV) compounds 1a, 1b, 2a–4a, and the telluride 3 together with its thiophene analogue (2,4,6-Me3C6H2)((2-C4H3S)COCH2)Te, 6 have been studied. Among the Te(IV) compounds, the functionalized organic moiety, FuCOCH2-, behaves as a (C, O) chelating ligand, resulting in a intramolecular 1,4-Te⋯O secondary bonding interaction. Such an interaction is absent in Te(II) compounds 3 and 6, though they differ in the conformation adopted by the organic ligand. The chalcogen atoms in the heteroaroyl moiety are trans in 3 but cis in 6 which also possesses intermolecular Te⋯O interaction in its lattice.

Grignard reagent prepared from 2-thiophenyl bromide in THF consumes elemental tellurium readily at room temperature and provides a route to obtain bis(2-thiophenyl)ditelluride, Tpn2Te2 (1, Tpn = 2-C4H3S) in good yield. It can also thiophenylate aryltellurium(II) bromides, producing solutions of mixed aryl(heteroaryl)tellurides, which when chlorinated give crystalline aryl(heteroaryl)tellurium(IV) dichlorides, ArTpnTeCl2 (Ar = 1-C10H7, Npl; 2,4,6-Me3C6H2, Mes). Oxidative addition of α-bromo-N,N-diethylacetamide to (2-thiophenyl)tellurium(II) bromide, gave the mixed alkyl(heteroaryl)tellurium(IV) dibromide, (Et2NCOCH2)TpnTeBr2. Ditelluride 1 can be detellurated by electrolytic copper to the bis(2-thiophenyl)telluride, Tpn2Te (2). Chemical shifts, δ(1H, 13C and 125Te) for (2-thiophenyl)tellurium(IV) halides are reported. Crystal structures of Tpn2TeBr2 (2b), Tpn2TeI2 (2c) and Mes(Tpn)TeCl2 (2e) have been determined unambiguously. In the case of 2e, steric repulsion of the mesityl ligand counters the tellurium lone pair repulsion to widen the equatorial C–Te–C angle to the extent of 108°. In the crystal lattices of 2b and 2c, the intermolecular Te⋯X secondary bonds give rise to an interesting tetrameric supramolecular architecture with S2 symmetry that defies the stereochemical activity of the lone pair on the central tellurium atom.

The stoichiometrically controlled chlorination of the diarylditelluride (8-Me(2) NC(10) H(6) Te)(2) with SO(2) Cl(2) afforded the aryltellurinyl chloride 8-Me(2) NC(10) H(6) TeCl (1) and the aryltellurium trichloride 8-Me(2) NC(10) H(6) TeCl(3) (2). Alternatively, 1 was obtained by the reaction of the aryltellurenyl diethyldithiacarbamate 8-Me(2) NC(10) H(6) Te(S(2) CNEt(2) ) with hydrochloric acid. The base hydrolysis of 2 provided the novel telluroxanes (8-Me(2) NC(10) H(6) Te)(2) OCl(4) (3), (8-Me(2) NC(10) H(6) Te)(6) O(5) Cl(8) (4), (8-Me(2) NC(10) H(6) Te)(6) O(8) Cl(2) (5), [(8-Me(2) NC(10) H(6) Te)(2) O(3) ](n) (6) and (8-Me(2) NC(10) H(6) Te)(6) O(8) (OH)(2) (7) depending on the reaction conditions applied. The reaction of 7 with ClTe(OiPr)(3) in the presence of water gave rise to the telluroxane (8-Me(2) NC(10) H(6) Te)(6) Te(2) O(12) Cl(2) (8). The crystal and molecular structures of 1-3 and 5-8 were determined by X-ray crystallography. The telluroxane clusters and polymers 6-8 hold potential as model compounds for alkali tellurite glasses (M(2) O)(x) (TeO(2) )(1-x) (M=Li, Na, K) for which no precise structural data are available.

Room temperature oxidative addition of α-bromo-2-acetylthiophene to elemental tellurium and aryltellurium(II) bromide provides direct routes to (2-thiophenoylmethyl)tellurium(IV) dibromides, (2-(C4H3S)COCH2)2TeBr2 (1b) and 2-(C4H3S)COCH2ArTeBr2 (Ar = 1-C10H7, Npl, 2b; 2,4,6-Me3C6H2, Mes, 3b). The chloro analogues, 2-(C4H3S)COCH2ArTeCl2 (Ar = Npl, 2a; Mes, 3a) were prepared by the condensation reaction of the parent methyl ketone with NplTeCl3 or MesTeCl3. Metathesis of these products with an alkali iodide affords the iodo analogues 1c, 2c and 3c. These diorganotellurium dihalides are reduced with aqueous bisulfite to diorganotellurides 1–3, which can be oxidized readily with dihalogens to the desired diorganotellurium(IV) dihalides. Compound 1 is a rare example of a symmetrical telluroether with Csp3–Te–Csp3 grouping that has been characterized by single-crystal diffraction techniques. Preference of the 2-thiophenoylmethyl ligand for small-bite (C, O) chelation over less strained (C, S) coordination is evident in the crystal structures of the Te(IV) compounds 1b, 2a, 2b and 3a. The unexpected transoidal orientation of the two acylmethyl ligands in the solid state molecular configuration of symmetrical diorganotellurium(IV) dibromide 1b appears to be a combined effect of electronic repulsion due to the thiophene moieties and steric repulsion of bromo ligands.

Elemental tellurium inserts into the Csp3–Br bond of α-bromomesitylmethyl ketone and due to its strong carbophilic character affords the crystalline C-tellurated derivative of 2,4,6-trimethylacetophenone, (MesCOCH2)2TeBr2, 1b in over 80% yield. Electrophilic substitution of the parent ketone with aryltellurium trichlorides, at room temperature, gives nearly quantitative yields of unsymmetrical alkylaryltellurium dichlorides (MesCOCH2)ArTeCl2 (Ar = mesityl, Mes, 2a; 1-naphthyl, Np, 3a; anisyl, Ans, 4a). Fairly stable mesitoylmethyltellurium(II) derivatives, (MesCOCH2)2Te, 1 and (MesCOCH2)ArTe (Ar = Mes, 2; Np, 3 and Ans, 4) obtained as the reduction products of their dihalotellurium(IV) analogues, readily undergo oxidative addition of dihalogens to afford the corresponding (MesCOCH2)2TeX2 (X = Cl, 1a; Br 1b; I, 1c) and (MesCOCH2)ArTeX2 (X = Cl, Br, I, Ar = Mes, 2a, 2b, 2c; Np, 3a, 3b, 3c and Ans, 4a, 4b, 4c). Crystallographic structural characterization of 1, 1b, 2, 2a, 2b, 2c, 3, 3a and 4c illustrates that the steric demand of mesityl group appreciably influences primary geometry around the 5-coordinate Te(IV) atom when it is bound directly to it. It also makes the Te atom inaccessible for the ubiquitous Te⋯X intermolecular secondary bonding interactions that result in supramolecular structures. In the crystal lattice of symmetrical telluroether 1, an interesting supramolecular synthon based upon reciprocatory weak C–H⋯O H-bonding interaction gives rise to chains via self-assembly.

Aqueous solutions of Me2Te(OH)2 and (CH2)4Te(OH)2 readily absorb carbon dioxide giving rise to the formation of the dialkyltelluroxane carbonates (Me2TeOTeMe2CO3)n (1) and HO(CH2)4TeOTe(CH2)4CO3Te(CH2)4OH·2H2O (2·2H2O), which were characterised by 13C MAS and 125Te MAS NMR spectroscopy as well as X-ray crystallography. The spatial arrangement of the tellurium atoms is defined by C2O2 donor sets in the primary coordination sphere and one or two secondary Te···O contacts, which involve coordination of the carbonate moieties. In turn, the different Te–O coordination modes render a lack of symmetry to the carbonate moieties, which show significantly different C–O bond lengths, an important feature when contemplating the C–O bond activation in carbonates. The structural and spectroscopic parameters of 1 and 2 are discussed in comparison with other heavy p-block element carbonates. In solution, electrolytic dissociation of 1 and 2 takes place.

The controlled base hydrolysis of 2,6-Mes(2)C(6)H(3)SnCl(3) (1; Mes=mesityl) provided 2,6-Mes(2)C(6)H(3)Sn(OH)Cl(2).H(2)O (2) and the trinuclear organostannonic acid trans-[2,6-Mes(2)C(6)H(3)Sn(O)OH](3) (3), respectively. In moist C(6)D(6), 3 reversibly reacts with water to give the monomeric organostannonic acid 2,6-Mes(2)C(6)H(3)Sn(OH)(3) (3 a). The reaction of 3 with (tBu(2)SnO)(3), Ph(2)PO(2)H, and NaH, gives rise to the multinuclear hypercoordinated organostannoxane clusters [tBu(2)Sn(OH)OSnR(OH)(2)OC(OSntBu(2)OH)(2)(O)SnR(OH)(H(2)O)](2) (5), [RSn(OH)(2)(O(2)PPh(2))](2) (6), and Na(3)(RSn)(4)O(6)(OH)(3) (7), respectively (R=2,6-Mes(2)C(6)H(3)). The characterization of the new compounds is achieved by multinuclear NMR spectroscopy and electrospray mass spectrometry in solution and (119)Sn MAS NMR spectroscopy, IR spectroscopy, and X-ray crystallography in the solid-state.

The diastereoselective synthesis of bis(3-endo-camphoryl)phosphinic acid (1) and its 2-bornen-2-yl ester 2 from the reaction of lithium camphor enolate with phosphorus trichloride and the hydrothermal synthesis of three chiral molecular metal(II) phosphinates of the type M(O2PR2)2·2R2P(O)OH [M = Co (3); Ni (4); Pb (5); R = 3-endo-camphoryl] from the reaction of 1 with metal(II) acetates or nitrates is described. The molecular structures of 1–5 are reported.

Organostannoxane drums [n-BuSn(O)O2C-C6H4-4-OR]6 [R = −CH3 (1); −C9H19 (2); −C11H23 (3)] and [n-BuSn(O)O2C-C6H3-3,5-(OR)2]6 [R = −CH3 (4); −C9H19 (5)] were synthesized by the reaction of n-BuSn(O)(OH) with the corresponding carboxylic acid in a 1:1 stoichiometry. Analogous reactions involving [n-Bu2SnO]n in a 1:1 stoichiometry afforded the diorganostannoxane ladders {[n-Bu2SnO2C-C6H4-4-OR]2O}2 [R = −CH3 (6); −C9H19 (7); −C11H23 (8)] and {[n-Bu2SnO2C-C6H3-3,5-(OR)2]2O}2 [R = −CH3 (9) and −C9H19 (10)]. Compounds 1−10 could also be prepared by a solventless methodology, which involved grinding the reactants together in a mortar and pestle at room temperature. Compounds 1−10 exhibit gelation behavior in aromatic solvents. In contrast, in aliphatic solvents gelation behavior was not observed. Among the organostannoxanes reported here, 2, 3, 5, and 8 were found to be extremely efficient gelators based on their critical gelation concentration values. The microstructure of the organometallic gels, investigated by...

Enantiomerically pure cis- and trans-myrtanylstannanes cis-MyrSnPh3 (1), trans-MyrSnPh3 (2), cis-MyrSnPh2Cl (3), trans-MyrSnPh2Cl (4), cis-MyrSnPhCl2 (5), trans-MyrSnPhCl2 (6), cis-MyrSnCl3 (7), trans-MyrSnCl3 (8) were synthesized and fully characterized by 1H, 13C and 119Sn NMR spectroscopy. The molecular structures of 1, 3, 6, 7, and [trans-MyrSn(OH)Cl2 · H2O]2 (8a) a hydrolysis product of 8, were determined by X-ray crystallography.

Bis(3-endo-camphoryl)phosphinic acid (1) was prepared by the reaction of the lithium enolate of D-(+)-camphor and phosphorous trichloride followed by an oxidative work up. Compound 1 crystallizes from wet toluene as monohydrate 1·H2O, which was investigated by X-ray crystallography. Molecules of 1 are associated by strong hydrogen bonds giving rise to the formation of a supramolecular helix. The interior channel of the helix is filled by a one-dimensional (1D) string of water molecules that are also associated by hydrogen bonding. The 1D string adopts a twisted zigzag conformation. Although the hydrogen bond networks are not cross-linked both the screw of the helix and the twist of the 1D string of water molecules are left-handed (M) and controlled by the chiral camphoryl residues situated on the exterior of the helix. The overall supramolecular structure is strongly reminiscent of aquaporin-1, a significant membrane-channel protein responsible for the transport of water into the cells.

series of enantiomerically pure bis(myrtanyl)tin compounds, cis-Myr2SnX2 (1, X = Ph; 3, X = Cl; 5, X = H) and trans-Myr2SnX2 (2, X = Ph; 4, X = Cl; 6, X = H) were prepared starting from (–)-1S-β-pi...

Nine diorganotin(IV) compounds of Schiff bases derived from salicylaldehyde/substituted salicylaldehyde and thiosemicarbazide were synthesized. The compounds, with general formulae [R2Sn(OArCHNNCSNH2)], where R = Me, n-Bu, Ph and Ar = C6H4, C6H3(5-Cl), C6H3(5-Br), were characterized by UV and IR spectroscopy, NMR (1H, 13C and 119Sn) spectroscopy and elemental analysis. X-ray crystallographic studies of five of these complexes indicate penta-coordination of tin within a distorted C2NOS trigonal bipyramidal geometry in each case. The crystal packing in four of the structures features {··· NCNH}2 synthons, but in [Ph2Sn(OArCHNNCSNH2)] the {··· SCNH}2 synthon is predominant. The biological activity of these compounds against four fungal pathogens (Curvularia eragrostidis, Alternaria porri, Dreschlerea oryzae and Macrophomina phaseolina) of four different crops (Camellia sineusis, Guizotia abyssinica, Oryzae sativa and Solanum melongena) and some bacteria (Aeromonas hydrophila, Salmonella typhi, Salmonella typhimurium, Salmonella flexnri, Escheria coli, Salmonella aureus, Bacillus subtilis and Lactobacillus rhamnosus) were investigated. Their cytotoxicity was also investigated against several human cancer cell lines. Copyright © 2007 John Wiley & Sons, Ltd.

The synthesis and characterization of unsymmetric diorganotellurium compounds containing a sterically demanding 1-naphthyl or mesityl ligand and a small bite chelating organic ligand capable of 1,4-Te⋯N(O) intramolecular interaction is described. The reaction of ArTeCl3 (Ar = 1-C10H7, Np; 2,4,6-Me3C6H2, Mes) with (SB)HgCl [SB = the Schiff base, 2-(4,4′-NO2C6H4CH NC6H3-Me)] or a methyl ketone (RCOCH3) afforded the corresponding dichlorides (SB)ArTeCl2 (Ar = Np, 1Aa; Mes, 1Ba) or (RCOCH2)ArTeCl2 (Ar = Np; R = Ph (2Aa), Me (3Aa), Np (4Aa); Ar = Mes, R = Ph (2Ba)). Reduction of 1Aa and 1Ba by Na2S2O5 readily gave the tellurides (SB)ArTe (Ar = Np (1A), Mes, (1B)) but that of dichlorides derived from methylketones was complicated due to partial decomposition to tellurium powder and diarylditelluride (Ar2Te2), resulting in poor yields of the corresponding tellurides 2A, 2B and 3A. Oxidation of the isolated tellurides with SO2Cl2, Br2 and I2 yielded the corresponding dihalides. All the synthesized compounds have been characterized with the help of IR, 1H, 13C, and 125Te NMR and in the case of 2Aa, and 2Ba by X-ray crystallography. Appearance of only one 125Te signal indicated that the unsymmetric derivatives were stable to disproportionation to symmetric species. Intramolecular 1,4-Te⋯O secondary bonding interactions (SBIs) are exhibited in the crystal structures of both the tellurium(IV) dichlorides, 2Aa, and 2Ba. Steric repulsion of the mesityl group in the latter dominates over lone pair–bond pair repulsion, resulting in significant widening of the equatorial C–Te–C angle. This appears to be responsible for the lack of Te⋯Cl involved supramolecular associations in the crystal structure of 2Ba.