Di(imino)aryltin(IV) dichlorides as tectons for heterometallic coordination compounds

Hydrolysis of [2-{(CH2O)2CH}C6H4]2SnCl2 (1) [prepared from 2-[(CH2O)2CH]C6H4MgBr and SnCl4, in 2 : 1 molar ratio] gave [2-(O=CH)C6H4]2SnCl2 (2). Treatment of with the appropriate amine, in the absence of a solvent or catalyst, resulted in the isolation in high yields of [2-(RN[double bond, length as m-dash]CH)C6H4]2SnCl2 [R = 2'-C10H7 (3), 2',4',6'-Me3C6H2 (4), PhCH2 (5), Me2NCH2CH2 (6), 2'-PyCH2 (7)]. The reaction of with [Pd(COD)Cl2] provided the heterometallic species [Cl2Pd{2-(2'-PyCH2N[double bond, length as m-dash]CH)C6H4}2SnCl2] (8). The compounds were characterised by multinuclear NMR spectroscopy in solution, and mass spectrometry and IR spectroscopy in the solid state. The molecular structures of 1, 2, 4-7 and 8·CH3CN were established by single-crystal X-ray diffraction. For all diorganotin(IV) dichlorides intramolecular O→Sn or Nimine→Sn coordination results in hypercoordinated species with a distorted octahedral (C,E)2SnCl2 core (E = O, N). The presence of intramolecular N→Sn interactions in solution, responsible for the restriction of free rotation of mesityl groups around the C-N(=C) single bonds, is suggested by (1)H and (13)C NMR data. In the heterometallic dinuclear complex 8 the octahedral coordination around tin is preserved as in 7 and the nitrogen atoms from the pyridyl groups in the pendant arms are coordinated to palladium, leading to a trans-square planar PdCl2N2 core.

Synthesis and biological activity of organoantimony(III)-containing heteropolytungstates

Three discrete organoantimony(III)-containing heteropolytungstates [(PhSb(III))(4)(A-α-Ge(IV)W(9)O(34))(2)](12-) (1), [(PhSb(III))(4)(A-α-P(V)W(9)O(34))(2)](10-) (2), and [{2-(Me(2)NCH(2)C(6)H(4))Sb(III)}(3)(B-α-As(III)W(9)O(33))](3-) (3) have been synthesized in one-pot reactions in aqueous medium using the appropriate lacunary heteropolyanion precursor and organoantimony(III) source. Polyanions 1-3 were isolated as hydrated salts, (NH(4))(12)[(PhSb(III))(4)(A-α-Ge(IV)W(9)O(34))(2)]·20H(2)O (1a), Rb(9)Na[(PhSb(III))(4)(A-α-P(V)W(9)O(34))(2)]·20H(2)O (2a), and Rb(3)[{2-(Me(2)NCH(2)C(6)H(4))Sb(III)}(3)(B-α-As(III)W(9)O(33))]·7H(2)O (3a). The compounds 1a-3a were fully characterized in the solid state using infrared (IR) spectroscopy, single-crystal XRD, and thermogravimetric and elemental analyses. The stability of 1-3 in aqueous solution was confirmed by multinuclear NMR ((1)H, (13)C, (31)P, and (183)W) spectroscopy. Preliminary studies on the biological activity of 1-3 showed that all three compounds might act as potent antimicrobial agents.

Organomercury(II) and tellurium(II) compounds with the "pincer" ligand 2,6-[O(CH2CH2)2NCH2]2C6H3--stabilization of an unusual organotellurium(II) cationic species

The reaction of RH (1) with Hg(OAc)(2), in EtOH, gave the acetate RHgOAc (2) [R = 2,6-[O(CH(2)CH(2))(2)NCH(2)](2)C(6)H(3)]. The corresponding RHgCl (3) was obtained from 2 and LiCl. The reaction of 3 with TeCl(4) (1:1 molar ratio), in anhydrous 1,4-dioxane, resulted in the transfer of the organic ligand from mercury to tellurium and the isolation of the unexpected ionic compounds [RTe](2)[Hg(2)Cl(6)] (4) and [RH(3)][HgCl(4)] (5). The molecular structures of 1-4 and 5·H(2)O were established by single-crystal X-ray diffraction. The acetate 2 and the chloride 3 are monomeric in solid state. In both mercury and tellurium organometallic compounds the organic group acts as an (N,C,N) "pincer" ligand. This coordination pattern provided stability for the rare [RTe](+) cation. Weak cation-anion interactions [Te···Cl 3.869(3) Å] are present between [RTe](+) and the dinuclear anion [Hg(2)Cl(6)](2-) in the crystal of 4. Theoretical calculations with DFT methods were performed for models of 3 and 4. The results show that in the cation of 4 the coordination of the nitrogen atoms play an important role for the stabilization of the structure found in the crystal whereas in 3 the coordination of the nitrogen atoms to the metal centre stabilizes to a less extent the structure found in solid state.

Bis(8-methyl-2,8-dicarba-closo-dodeca-boran-2-yl) tris-elenide

In the title compound, C₆H₂₆B₂₀Se₃, the geometry around the central Se atom is V-shaped, with the Se—Se—Se angle being 105.60 (4)°. The Se—Se bond lengths are consistent with single covalent bonds.

Di-μ-chlorido-bis[chloridobis(dimethyl sulfoxide-κO)tin(II)]

The structure of the title compound, [Sn₂Cl₄(C₂H₆OS)₄], contains dimers formed through weak Sn⋯Cl [3.691 (2) Å] inter­actions, resulting in a planar Sn₂Cl₂ core with an inversion center at the centre of the four-membered ring. The Sn^II atoms are penta­coordinated and have a distorted octa­hedral Ψ-SnCl₃O₂ coordination geometry. The O atoms from the dimethyl sulfoxide mol­ecules occupy trans positions, while the Cl atoms exhibit a meridional arrangement.

μ-Carbonato-bis-(bis-{2-[(diethyl-amino)-meth-yl]phen-yl}bis-muth(III))

The mol­ecular structure of the title compound, [Bi₂(C₁₁H₁₆N)₄(CO₃)], consists of a symmetrically bridging carbonato group which binds two [2-Et₂NCH₂C₆H₄]₂Bi units that are crystallographically related via a twofold rotation axis bis­ecting the carbonate group. The two Bi atoms and two of the C atoms directly bonded to bis­muth are quasi-planar [deviations of 0.323 (1) and 0.330 (9)Å for the Bi and C atoms, respectively] with the carbonate group. The remaining two ligands are in a trans arrangement relative to the quasi-planar (CBi)₂CO₃ system. The metal atom is strongly coordinated by the N atom of one pendant arm [Bi—N = 2.739 (6) Å], almost trans to the O atom, while the N atom of the other pendant arm exhibits a weaker intra­molecular inter­action [Bi⋯N = 3.659 (7) Å] almost trans to a C atom. If both these intra­molecular N→Bi inter­actions per metal atom are considered, the overall coordination geometry at bis­muth becomes distorted square-pyramidal [(C,N)₂BiO cores] and the compound can be described as a hypervalent 12-Bi-5 species. Additional quite short intra­molecular Bi⋯O inter­actions are also present [3.796 (8)–4.020 (9) Å]. Inter­molecular associations through weak η⁶⋯Bi inter­actions [Bi⋯centroid of benzene ring = 3.659 (1) Å] lead to a ribbon-like supra­molecular association.

Study of the coordination abilities of stibine ligands to gold(I)

The reaction of [AuCl(tht)] (tht = tetrahydrothiophene) with SbMes(n)Ph(3-n) (n = 3 (1), 2 (2), 1 (3)) produces the 1:1 adducts [AuCl(SbMes(n)Ph(3-n))] (n = 3 (4), 2 (5), 1 (6)), with a Sb-Au-Cl environment, regardless of the molar ratio used (1:1 to 1:4). Addition of the same stibines to [Au(tht)(2)]ClO(4) (molar ratio 1:1 to 1:4) results in isolation of the 1:2 adducts [Au(SbMes(n)Ph(3-n))(2)]ClO(4) (n = 3 (7), 2 (10)), containing linear Sb-Au-Sb fragments, or the 1:3 adduct [Au(SbMesPh(2))(3)]ClO(4) (11), with a quasi trigonal planar AuSb(3) core. The same 1:2 cations are produced when [Au(tht)(2)]CF(3)SO(3) is reacted with 1 or following a rearrangement process when 4 is treated with AgSbF(6), that is, [Au(SbMes(3))(2)]X (X = CF(3)SO(3) (8), SbF(6) (9)). The compounds were characterized by spectroscopic methods, and the molecular structures of 2-4, 7, 8.2CDCl(3), 9, and 11 were established by single-crystal X-ray diffraction. Theoretical calculations were carried out on model systems of type ER(3) and [Au(ER(3))(n)](+) (E = P or Sb; R = Ph or Mes; n = 2, 3, or 4) to gain insight into the bonding nature of SbR(3) ligands in homoleptic gold-stibine adducts, in comparison with phosphine-gold(I) compounds. Steric effects govern the coordination of stibines with mesityl substituents. A preference for higher coordination numbers is observed for SbPh(3) when compared with PPh(3) and experimentally observed C-Sb-C and Sb-C structural distortions of stibines upon coordination are reproduced theoretically.

3,5-Dibromo-2',3',4',5',6'-penta-methyl-1,1'-biphen-yl

In the crystal structure of the title compound, C(17)H(18)Br(2), the benzene rings are almost perpendicular [dihedral angle = 84.0 (3)°]. The crystal structure is consolidated by the presence of C-Br⋯π inter-actions.

Dichlorido[(Z)-4-(2,6-diisopropyl-anilino)pent-3-en-2-one]dimethyl-tin(IV)

In the crystal structure of the title compound, [Sn(CH₃)₂Cl₂(C₁₇H₂₅NO)], the Sn atom adopts a trigonal-bipyramidal geometry with the O and one Cl atom in axial positions. A weak intra­molecular N—H⋯O hydrogen bond occurs. The crystal structure displays weak inter­molecular C—H⋯Cl inter­actions.

[2-(4-Methyl-piperazin-1-ylmeth-yl)phen-yl]diphenyl-phosphane

In the title compound, C(24)H(27)N(2)P, the P atom is bonded to three C atoms in a trigonal-pyramidal geometry. The overall Ψ-trigonal-bipyramidal coordination of the P atom is established when the contribution of the electron lone pair and of the N-P donor-acceptor distance of 3.051 (3)Å are considered. The 4-methyl-piperazinyl ring adopts a chair conformation. Intra- and inter-molecular C-H⋯π hydrogen bonding leads to the consolidation of the structure.

Bis[2-(morpholinometh-yl)phen-yl]phenyl-phosphane

The title compound, C(28)H(33)N(2)O(2)P, contains a penta-coordinated P atom as a result of the weak N→P intra-molecular inter-actions, with three C atoms, two N atoms and the lone pair arranged in a dicapped pseudo-tetra-hedral geometry. The morpholine rings exhibit an almost ideal chair conformation. In the crystal, two weak C-H⋯O hydrogen-bond inter-actions link the mol-ecules in layers stacked along the a axis; there are no further inter-actions between the layers.

Chloridobis{2-[(dimethyl-amino)-meth-yl]phen-yl}anti-mony(III)

In the title compound, [Sb(C(9)H(12)N)(2)Cl], the Sb atom adopts a Ψ-trigonal-bipyramidal geometry. The two 2-[(dimethyl-amino)-methyl]-phenyl ligands are coordinated asymmetrically to the Sb atom. The carbon atoms of one of the ligands are disordered over sets of sites with equal occupancy, resulting in two conformational isomers in the crystal. The Sb-C and Sb-N distances in the ordered ligand are: 2.153 (4) and 3.326 (5) Å, respectively. The corresponding distances in the disordered ligand are: 2.103 (5)/2.188 (5) and 2.454 (3) Å, respectively. The structure displays intra-molecular C-H⋯Cl hydrogen bonding.

Organotin meclofenamic complexes: Synthesis, crystal structures and antiproliferative activity of the first complexes of meclofenamic acid - novel anti-tuberculosis agents

The complexes [Me(2)(Meclo)SnOSn(Meclo)Me(2)](2) (2) and [Ph(3)Sn(Meclo)] (3) where HMeclo is meclofenamic acid, N-(2,6-dichloro-m-tolylanthranilic acid)], have been prepared and structurally characterized by means of vibrational, (1)H and (13)C NMR spectroscopies. The crystal structure of complexes (2) and (3) have been determined by X-ray crystallography. Three distannoxane rings are present to the dimeric tetraorganodistannoxane of planar ladder arrangement of (2). The structure is centro symmetric and features a central rhombus Sn(2)O(2) unit two additional tin atoms linked at the oxygen atoms. Five- and six-coordinated tin centers are present in the dimer distannoxane. X-ray analysis of (3) revealed a penta-coordinated structure containing Ph(3)Sn coordinated to the chelated carboxylato group. The polar imino hydrogen atom participates in intra-molecular hydrogen bonds. Complexes (2) and (3) are self-assembled via pi-->pi, C-H-pi, stacking interactions and intra-molecular hydrogen bonds. Meclofenamic acid and [Ph(3)Sn(Meclo)] have been evaluated for antiproliferative activity in vitro against three human cancer cell lines: MCF-7 (human breast cancer cell line), T24 (bladder cancer cell line), A-549 (non-small cell lung carcinoma) and a mouse L-929 (a fibroblast-like cell line cloned from strain L). The [Ph(3)Sn(Meclo)] complex exhibited high cytotoxic activity against all the cancer cell lines. Meclofenamic and [Ph(3)Sn(Meclo)] were tested for anti-mycobacterial activity against Mycobacterium tuberculosis H37Rv. The [Ph(3)Sn(Meclo)] complex was found to be a promising anti-mycobacterial lead compound, displaying high activity against M. tuberculosis H37Rv.

Hydrogen bonding in substitutionally disordered di-μ-hydroxido-bis-{aqua-tri[bromido/chlorido(1/2)]tin(IV)} acetone disolvate

The structure of the title compound, [Sn₂Br_1.97Cl_4.03(OH)₂(H₂O)₂]·2C₃H₆O, contains two hexa­coordinated Sn atoms bridged symmetrically by two hydroxide groups, with an inversion center in the middle of the planar Sn₂O₂ ring, half of the mol­ecule being generated by inversion symmetry. The other sites of the distorted octa­hedral coordination geometry are occupied by halide atoms and water mol­ecules. The structure exhibits substitutional disorder of the halide atoms bonded to the Sn atom, with 0.672 (4) occupancy for Cl and 0.328 (4) for Br for each halide position. The compound crystallizes with two acetone mol­ecules, which are involved in intra- and inter­molecular O—H⋯O contacts. The water mol­ecules coordinated to the Sn atoms are also involved in O—H⋯O and O—H⋯X contacts, leading to a polymeric array along the a axis.

Heterocycles 21. Reaction of 2-phenyl-thiazol-4-carbaldehyde with 2-bromoacetophenone

The condensation reaction of 2-phenyl-thiazol-4-carbaldehyde with 2-bromoacetophenone was performed in basic catalysis, resulting in a mixture of 2,3-epoxy-1-phenyl-3-(2-phenyl-thiazol-4-yl)-propan-1-one (1), 1-phenyl-3-(2-phenyl-thiazol-4-yl)-propane-1,2-dione (2) and 2-phenyl-4,5-bis-(2-phenyl-thiazol-4-yl)-3-hydroxy-furane (4). The isolated solids were structurally investigated by spectroscopic methods, i.e. infrared spectroscopy, mass spectrometry and NMR. In solution the dicarbonylic derivative 2 undergoes a tautomeric process, resulting in the enol 2-hydroxy-1-phenyl-3-(2-phenyl-thiazol-4-yl)-prop-2-en-1-one 3. Compounds 3 and 4 were transformed in the corresponding acetyl derivatives 5 and 6, respectively, by reacting them with acetic anhydride. For the furane 4 the single crystal X-ray diffraction structure was determined.

4-Benzylpiperazin-1-ium chloride chloroform solvate

The ions of the title chloro­form-solvated salt, C₁₁H₁₇N₂⁺·Cl⁻·CHCl₃, are linked by a strong N—H⋯Cl hydrogen bond; the solvent mol­ecule also inter­acts with the chloride ion through a C—H⋯Cl hydrogen bond. Additionally, neighboring cations form weak hydrogen bonds to the anion, resulting in a supra­molecular ribbon that runs along the a axis.

Di-μ-chlorido-bis-{[2-(morpholinometh-yl)phenyl-κC,N]palladium(II)}

The title compound, [Pd(2)(C(11)H(14)NO)(2)Cl(2)], has a dimeric structure with Cl atoms bridging the two Pd atoms, one half of the mol-ecule being generated by symmetry due to the crystallographic inversion centre located in the middle of the perfectly planar Pd(2)Cl(2) ring. The five-membered ring adopts an envelope conformation, while the morpholino group has a chair conformation. The geometry around the metal centres is distorted square-planar, as a result of a strong intra-molecular N→Pd coordination trans to a Pd-Cl bond. In the crystal structure, the dimeric structure is strengthened by inter-molecular C-H⋯Cl hydrogen bonds. C-H⋯C(phen-yl) inter-actions link the dimers into a columnar supra-molecular array along the a axis; the dimers are further connected by C-H⋯Ph inter-actions into a three-dimensional supra-molecular arrangement.