Crystal structure of caesium tetra-methyl-dithio-imidodiphosphinate.

In the title crystal, the salt [CsMe2P(S)NP(S)Me2] is self-assembled as an undulating supra-molecular two-dimensional polymeric structure, poly[(µ4-tetra-methyl-dithio-imidodiphosphinato)caesium], [Cs(C4H12NP2S2)] n , which is parallel to the bc plane. The Cs cations are hexa-coordinated, being chelated by two thio-imidophosphinate groups and two sulfur atoms from neighboring ligands. The anions are linked to the Cs cations by Cs⋯S and Cs⋯N electrostatic inter-actions.

Lanthanide(III) complexes with 4,5-bis(diphenylphosphinoyl)-1,2,3-triazolate and the use of 1,10-phenanthroline as auxiliary ligand.

New lanthanide complexes with 4,5-bis(diphenyl)phosphoranyl-1,2,3-triazolate (L(-)), LnL(3).nH(2)O (1-8) and LnL(3)(phen).nH(2)O (9-16) (Ln = La, Ce, Nd, Sm, Eu, Gd, Tb, Er), have been prepared and spectroscopically characterized. The structures of LnL(3).nH(2)O (Ln = La, Ce, Nd, Sm and Gd) were determined by X-ray crystallography. The metal centers exhibit a distorted trigonal dodecahedron coordination environment with two symmetrically O,O-bidentate ligands and one unsymmetrically O,N- ligand attached to the metal; two oxygen atoms from neighboring dimethyl sulfoxide (DMSO) molecules complete the coordination sphere. This unsymmetrical ligand coordination behavior was also identified in solution through (31)P{(1)H} NMR studies. Photoluminescence spectroscopy experiments in CH(2)Cl(2) for both types of complexes containing Eu(III) (6, 14) and Tb(III) (7, 15) exhibit strong characteristic red and green emission bands for Eu(III) and Tb(III), respectively. Furthermore, NdL(3) (phen).5H (2)O (11) displays emission in the near-infrared spectral region ((4)F(3/2) --> (4)F(9/2) at 872 nm and (4)F(3/2) --> (4)F(11/2) at 1073 nm). The complexes containing 1,10-phenantroline exhibit higher quantum yields upon excitation at 267 nm, indicating that this auxiliary ligand promotes the luminescence of the complexes; however, luminescence lifetimes (tau) in this case are shorter than those of the LnL(3).nH(2)O series.

Coordination diversity of aluminum centers molded by triazole based chalcogen ligands.

Equimolar and excess ratio reactions of AlMe(3) and Al(i)Bu(3) with the ligands 4,5-(P(E)Ph(2))(2)tzH (tz = 1,2,3-triazole; E = O (1), S (2), Se(3)) were performed, showing a vast variety of coordination modes. The products obtained, [AlR(2){kappa(2)-O,O'-[4,5-(P(O)Ph(2))(2)tz]}] (R = Me (4), (i)Bu (5)), [AlR(2){kappa(3)-N,N',S-[4,5-(P(S)Ph(2))(2)tz]}(mu-tz)](2) (R = Me (6), R = (i)Bu (7)), [AlMe(2){kappa(2)-N,Se-[4,5-(P(Se)Ph(2))(2)tz]}] (8), [Al{kappa(2)-N,Se-[4,5-(P(Se)Ph(2))(2)tz]}(3)] (9), [AlR(2){kappa(2)-O,O'-[4,5-(P(O)Ph(2))(2)tz]}-(N'-AlR(3))] (R = Me (10), (i)Bu (11)), and [AlR(2){kappa(2)-N,S-[4,5-(P(S)Ph(2))(2)tz]}-(N'-AlR(3))] (R = Me (12), R = (i)Bu (13)), were characterized by spectroscopic methods, and the structures of 1, 4, 6, 7, 9, 10, and 12 were obtained through X-ray diffraction studies. Theoretical calculations were performed on the deprotonated ligands and on selected compounds to obtain information regarding the coordination variety observed for these compounds.

Solubilizing functionalized molecular aluminosilicates.

Molecular aluminosilicate Al(SH)(micro-O)Si(OH)(O(t)Bu)(2) ( = [HC{C(Me)N(Ar)}(2)](-), Ar = 2,6-(i)Pr(2)C(6)H(3)) has been prepared from Al(SH)(2) and ((t)BuO)(2)Si(OH)(2) in high yield. When reacted with one equiv. of water, the unique aluminosilicate containing two terminal hydroxy groups Al(OH.THF)(mu-O)Si(OH)(O(t)Bu)(2) can be isolated. However, when is reacted with the bulkier silanol ((t)BuO)(3)SiOH, no reaction is observed. The desired Al(SH)(micro-O)Si(O(t)Bu)(3) can be prepared in a two-step synthesis between AlH(2) and ((t)BuO)(3)SiOH giving first Al(H)(micro-O)Si(O(t)Bu)(3), which reacts further with elemental sulfur to give as the only product. Direct hydrolysis of was conducted to obtain Al(OH)(micro-O)Si(O(t)Bu)(3), however, such hydrolysis always resulted in a complete decomposition of the starting material. Therefore we used boric acid, which condenses in non-polar solvents and slowly evolve water, to hydrolyze to under mild conditions. Compounds , and have been characterized by single-crystal X-ray diffraction.

Structural variety of alkali metal compounds containing P-E-M (E = S, Se; M = Li, Na, K) units derived from nitrogen rich heterocycles.

The preparation of novel alkali metal chalcogenides supported by multidentate nitrogen rich ligands is reported. Treatment of the ligand precursors [H{(4,5-(P(E)Ph(2))(2)tz}] (E = S (1a), Se (1b)) with organolithium reagents or elemental sodium and potassium in tetrahydrofuran (THF) leads to the isolation of 2-7 in high yields. These compounds were characterized by elemental analysis, IR spectroscopy, mass spectrometry, solution and solid-state multinuclear NMR spectroscopy, and single crystal X-ray diffraction analysis. In the solid state, 2, 4, and 5 are dimers that contain bimetallic six-membered (M(2)N(4)) rings (M = Li, Na). In 3, the discrete monomer [Li{4,5-(P(Se)Ph(2))(2)tz}(thf)(2)] (tz = 1,2,3-triazole) contains a five-membered CPSeLiN ring which adopts an envelope conformation. The polymeric arrangement [K{4,5-(P(S)Ph(2))(2)}tz](infinity) in 6 displays different bonding modes based on the hapticity of the ligand upon binding to the potassium atom. In compounds 2-6, the presence of secondary bonding features the alkali metal chalcogen bonds.

Soluble, reactive and stable - unique aluminosilicate ligands and a heterobimetallic derivative [LAl(SLi)(micro-O)Si(OLi.2thf)(OtBu)2]2.

The heterobimetallic aluminosilicate [LAl(SLi)(micro-O)Si(OLi.2thf)(O(t)Bu)(2)](2) was prepared from the LAl(SH)(micro-O)Si(OH)(O(t)Bu)(2) (L = [HC{C(Me)N(Ar)}(2)](-), Ar = 2,6-di-(i)Pr(2)C(6)H(3)) ligand, which can also be hydrolyzed to LAl(OH.thf)(micro-O)Si(OH)(O(t)Bu)(2)- leading to the first aluminosilicate-dihydroxide soluble in organic solvents.

An unknown coordination mode of the phosphite unit and a carbon-free heterocycle in two different heterobimetallic alumophosphites.

The unique alumophosphite reagent LAl(SH)(mu-O)P(OEt)2 was prepared and used for the synthesis of the heterobimetallic alumophosphites [{kappa2-S,P-LAl(S)(mu-O)P(OEt)2}2Zn] and [{kappa4-S,O,O-LAl(SLi)(mu-O)P(OEt)2}2]. The first contains a rare example of two carbon-free five-membered heterocycles (Al-S-Zn-P-O) connected in a spiro fashion through the zinc atom, whereas the second possesses an unknown example of a coordination environment of a phosphite unit M-O-P(mu-OEt)2M with an uncoordinated lone electron pair on the phosphorus center.

Synthesis and characterization of aluminum-containing tin(IV) heterobimetallic sulfides.

Three novel aluminum-containing tin(IV) heterobimetallic sulfides are reported. The reaction of [LAl(SLi)2(THF)2]2 (1) [L = HC(CMeNAr)2, Ar = 2,6-iPr2C6H3] with Ph2SnCl2, Me2SnCl2, and SnCl4 in THF respectively afforded LAl(mu-S)2SnPh2 (2), LAl(mu-S)2SnMe2 (3), and LAl(mu-S)2Sn(mu-S)2AlL (4) in moderate yields. Compounds 2, 3, and 4 were characterized by elemental analysis, NMR, electron-impact mass spectrometry, and single-crystal X-ray structural analysis.

Oxidative degradation of ethers promoted by strontium and barium tetraphenylimidodiphosphinates.

The novel M[(OPPh2)2N]2.nTHF (M = Sr (2), Ba (3)) complexes were prepared and characterized. Upon exposure to atmospheric oxygen, 2 and 3 were transformed to the dinuclear species Sr2-[(OPPh2)2N]4.2C3H6O3 (4) and Ba(2)[(OPPh2)2N]4.2C4H8O3 (5), respectively. Compounds 4 and 5 contain coordinated carboxylic acids obtained from the oxidative degradation of DME and THF, respectively, which were used as solvents for crystallization.

True square planar [M{N(SePiPr2)2-Se,Se'}2][M = Sn, Se] complexes. An extraordinary geometrical arrangement for well known centers [Sn(II), Se(II)].

The syntheses and molecular structures of [M{N(SeP(i)Pr2)2-Se,Se'}2][M = Sn(2), Se(3)] are described, these complexes consist of discrete, monomeric molecules featuring MSe4 cores that comprise true square-planar geometries.

Template-assisted self assembly of two lipophilic polyion aggregates derived from sodium tetraphenyl imidodiphosphinate-complexes containing sodium ions in four different coordination environments.

The molecular structures of two lipophilic polyion aggregates derived from tetraphenyl imidodiphosphinate are described: [Na(crown ether)][MNa(2)[Ph(2)P(O)NP(O)Ph(2)](4)] with crown ether = 15-crown-5 for 1and benzo-15-crown-5 for (M = Na(+) for 1 and Na(H(2)O)(+) for 2).

S-adenosyl-L-methionine is able to reverse micronucleus formation induced by sodium arsenite and other cytoskeleton disrupting agents in cultured human cells.

Deficiencies of folic acid and methionine, two of the major components of the methyl metabolism, correlate with an increment of chromosome breaks and micronuclei. It has been proposed that these effects may arise from a decrease of S-adenosyl-L-methionine (SAM), the universal methyl donor. Some xenobiotics, such as arsenic, originate a reduction of SAM levels, and this is believed to alter some methylation processes (e.g. DNA methylation). The aim of the present work was to analyze the effects of exogenous SAM on the micronucleus (MN) frequency induced by sodium arsenite in human lymphocytes treated in vitro and to investigate whether these effects are related to DNA methylation. Results showed a reduction in the MN frequency in cultures treated with sodium arsenite and SAM compared to those treated with arsenite alone. To understand the mechanism by which SAM reduced the number of micronucleated cells, its effect on MN induced by other xenobiotics was also analyzed. Results showed that SAM did not have any effect on the increase in MN frequency caused by alkylating (mitomycin C or cisplatin) or demethylating agents (5-azacytidine, hydralazine, ethionine and procainamide), but it reduced the number of micronucleated cells in those treated with agents that inhibit microtubule polymerization (albendazole sulphoxide and colcemid). Since albendazole sulphoxide and colcemid inhibit microtubule polymerization, we decided to evaluate the effect of SAM on microtubule integrity. Data obtained from these evaluations showed that sodium arsenite, albendazole sulphoxide, and colcemid affect the integrity and organization of microtubules and that these effects are significantly reduced when cultures were treated at the same time with SAM. The data taken all together point out that the positive effects of SAM could be due to its ability to protect microtubules through an unknown mechanism.

Cytotoxic Activities of O-Cholesteryl-O-Phenyl-N-Phenylphosphoramidate and Its Organometallic Tin(lV) Derivatives.

O-Cholesteryl-O-phenyl-N-phenylphosphoramidate (1) and four organotin (lV) derivatives of the ambidentate O-cholesteryl-O -phenyl phosphorothioate ligand formulated as Me(3) SnOSPR'R"(2), Ph(3)SnOSPR'R"(3), O(CH(2)CH(2)S)(2)Sn(n-Bu)OSPR'R"(4), S(CH(2)CH(2)S)(2)Sn(n-Bu)OSPR'R"(5), (R' = O-phenyl; R"= O-cholesteryl) were subjected to cytotoxicity screening against KB (nasopharingel carcinoma), OVCAR-5 (ovarium carcinoma) and SQC-1 UlSO (squamous cell cervix carcinoma) cell cultures. The results of the bioassay showed that these compounds possess potent antitumor activities against the studied human carcinoma cell lines.

Stereochemical Consequences of the Bismuth Atom Electron Lone Pair, a Comparison between MX(6)E and MX(6) Systems. Crystal and Molecular Structures of Tris[N-(P,P-diphenylphosphinoyl)-P,P-diphenylphosphinimidato]bismuth(III), [Bi{(OPPh(2))(2)N}(3)], -indium(III), [In{(OPPh(2))(2)N}(3)].C(6)H(6), and -gallium(III), [Ga{(OPPh(2))(2)N}(3)].CH(2)Cl(2).

The tetraphenylimidodiphosphinate [N-(P,P-diphenylphosphinoyl)-P,P-diphenylphosphinimidate] ion forms stable tris-chelates with the Bi(III), In(III), and Ga(III) cations. The crystal and molecular structures of [M{(OPPh(2))(2)N}(3)] (M = Ga, In, Bi) were determined by X-ray diffractometry. The geometry around the bismuth atom in compound 3 displays an approximately C(3)(v)() symmetry. This arrangement suggests the presence of a stereoactive lone pair of electrons, which is located in one of the triangular octahedral faces. Derivative 3 crystallizes in the triclinic space group P&onemacr; with Z = 2, a = 14.006(6) Å, b = 14.185(4) Å, c = 17.609(8) Å, alpha = 88.45(2) degrees, beta = 79.34(2) degrees, and gamma = 78.23(2) degrees. The structures of the gallium(III) and indium(III) tris-chelate oxygen-based complexes (1 and 2, respectively) were compared with the bismuth analogue in order to determine the ligand steric bulk influence on the coordination sphere in the absence of the electron lone pair. Complex 1 crystallizes as the [Ga{(OPPh(2))(2)N}(3)].CH(2)Cl(2) solvate in the triclinic space group P&onemacr;; Z = 2, a = 13.534(4) Å, b = 13.855(4) Å, c = 18.732(7) Å, alpha = 95.48(2) degrees, beta = 98.26(2) degrees, and gamma = 97.84(2) degrees. Crystal data for the benzene solvate of 2, [In{(OPPh(2))(2)N}(3)].C(6)H(6): triclinic space group P&onemacr;, Z = 2, a = 13.542(9) Å, b = 15.622(3) Å, c = 18.063(5) Å, alpha = 98.21(1) degrees, beta = 104.77(0) degrees, and gamma = 92.260(0) degrees.