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The silylated ferrocenyl selenium reagent 1,1′-Fe(η5-C5H4SeSiMe3)2 has been used for the high yield formation of the phosphine-ligated copper complexes Cu2(fcSe2)(PtPr3)2 (1) and Cu4(fcSe2)2(PnPr3)4 (2) from solublilized CuOAc, as determined by single-crystal X-ray diffraction. The incorporation of a source of Se2- into the reaction scheme with the reagent Se(SiMe3)2 yields the mixed selenide/ferrocenyldiselenolate cluster [Cu20Se6(Se2fc)4(PnPr3)10] (3). Partial substitution of the PnPr3 ligand shell in 3 with the phosphinothiol Ph2P(CH2)3SH leads to an expansion of the framework and the high yield formation of the crystallographically characterized cluster Cu36(fcSe2)6Se12(PnPr3)10(Ph2P(CH2)3SH)2 (5), which contains surface alkylthiol groups on a copper-selenium core. [ABSTRACT FROM AUTHOR]

Studies the syntheses of Ru-S clusters with kinetically labile ligands via photolysis. Derivatives; Attempted synthesis; Electrochemistry.

CuCI and bis(diphenylphosphanyl)metharre (dppm) react in the presence of small amounts of FeCl3 with PhSeSiMe3 and Se(SiMe3)2 to yield [Cu30Fe2Se6(SePh)24(dppm)4]. The crystal structure of the compound was determined by single-crystal X-ray analysis to give a mixed copper selenide/selenolate cluster molecule of a new structural type incorporating Iwo central iron atoms. The formal oxidation state of the iron atoms was determined by Mbssbauer spectroscopy to be +3, in agreement with quantum chemical calculations and modeling of the magnetic data. In addition, Mdssbauer studies show no magnetic hyperfine structure in zero field, and the magnetically perturbed spectrum displays a pattern typical tora diamagnetic species in a transverse field, suggesting a singlet ground state. However, the inclusion of the iron atoms has a distinct influence on the optical properties of the compound compared to similar clusters containing only copper and selenium atoms. [ABSTRACT FROM AUTHOR]

Examines the class of ruthenium sulfide clusters. Characterization of clusters in nitrogenase; Administration of chromatographic purification of hydrolyzed samples; Formation of rationalized conformation of H[sub 2].

The Co(II) and Mn(II) complexes (tmeda)Co(ESiMe3)2 (E = S, la; E = Se, 1 b), (3,5-Me2C5H3N)2Co(ESiMe3)2 (E = S, 2a; E = Se, 2b), [Li(tmeda)]2[(tmeda)Mn5(μ-ESiMe3)2(ESiMe3)4(μ4-E)(μ3-E)2] (E = S, 3a; E = Se, 3b), [Li(tmeda)]2[Mn(SSiMe3)4] (4), [Li(tmeda)]4[Mn4(SeSiMe3)4(μ3-Se)4] (5), and [Li(tmeda)]4[Mn(Se4)3] (6) (tmeda = N,N,N,N-tetramethylethylenediamine) have been isolated from reactions of Li[ESiMe3] and the chloride salts of these metals. The treatment of (tmeda)CoCl2 with two equivalents of Li[ESiMe3] (E = S, Se) yields la and 1 b, respectively, whereas similar reactions with MnCl2 yield the polynuclear complexes 3a (E = S) and 3b (E = Se). The selective preparation of the mononuclear complex 4 is achieved by increasing the reaction ratios of Li[SSiMe3J to MnCl2 to 4:1. Single crystal X-ray analysis of complexes 1-5, confirms the presence of the trimethylsilylchalcogenolate moieties and distorted tetrahedral geometry around the metal centers in each of these complexes. The structure of the tris(tetraselenide) complex [Li(tmeda)]4[Mn(Se4)3] (6), isolated in small quantities from the preparation of 5, is also described. [ABSTRACT FROM AUTHOR]

The bifunctional Iigand estechol-4,5 dithiol, H2Dtcat, has been synthesized, and the structure of the bin Br adduct, (HS)2C6H2(OH)2·2Ph4Br·H2O, has been determined. The syntheses, molecular structures, electronic structures, and magnetic properties of the monoanionic [(Dtcat2-)2M], (M = Ni, V and M o Cu, VI) complexes have been obtained as Ph4PBr double salts, [M(S2C6H2(OH)2)2][Ph4P]3Br2. These and the antiferromagnetically coupled dimetic [(Dtcal)2 Fe][Ph4P]2·4DMF domplex, VII, have been structurally chaiacterized. The centrosymmetric (M(S2C6H2(OH)f complexes in the X-ray isomorphous V and Vi are connected via H-bonding to Br ions to form one-dimensional chains well separated from each other by the Ph4P+ cations. Magnetic measurements show V to be a S o ½ and VI a S = O molecules. The distribution of electrons in these compounds have been determined by density functional theory calculations which show V to be a radical anion Ni(ll) complex and Via partially otddiced-Iigand, reduced-copper complex. The 4,5 dithio-oquinorle [(Dtoq)2Ni][Ph4P]2 and [(Dtoq)2Cu][Ph4P]2 orthoquinone derivatives of V and VI have been obtained by oxidaton, and their molecular structures have been determined. The dimetic ([FeS2C6H2(OH)2)2)2- complex, (VII) also cystallizes in chains where all OH groups partidpate in extensive H-bonding. The structure of the dianion VII contains S-coordinated Fe(Ill) tais in a square pyramidal coordination. In VII, two low spin Fe(III) (S = ½) sites are weakly coupled antitenomagneticalty with a μeff of 2.81BM at 270 K and 0.91 BM at 10 K. [ABSTRACT FROM AUTHOR]

Sandwich-type lanthanide complexes with macrocyclic ligand cucurbit[6]uril (C36H36N24O12, CB[6]) were synthesized under hydrothermal conditions from aqueous solutions of lanthanide(lll) bromides, CB[6], and 4-cyanopyridine. According to X-ray analysis (Ln = La, Pr, Dy, Ho, Er, and Yb), the compounds with different structural types of lanthanide cores have a common fragment where the tetranuclear hydroxo complex is sandwiched between two macrocycles {(lN@CB[6])Ln4(μ3-OH)4(lN@CB[6])}6+ (IN = isonicotinate). The photoluminescence (for Ln = Eu) and Fourier transform ion cyclotron resonance mass spectra (for Ln = Pr, Dy, and Er) were studied. The compounds are used for the first time as precursors for the synthesis of lanthanide-silver heterometallic coordination polymers. The chainlike crystal structure of polymers (Ln = La, Pr, and Dy) is constituted by the sandwich complexes linked via the coordination of IN nitrogen atoms to the silver atoms. [ABSTRACT FROM AUTHOR]

Inclusion compounds of a macrocyclic cavitand cucurbit[8]uril (CB[8]) with cobalt(III) and nickel(II) complexes of 1,3-diaminopropane (tn) and 1,3-diamino-2-propanol (tmOH) {trans-[Co(tn)2Cl2] @ CB[8]}Cl · 14H2O (1), {trans-[Co(tmOH)-(tmO))@CB[8]}Cl2 · 22H2O (2), and {trans-[Ni(tmOH)2]@CB[8]}Cl2 · 22H2O (3) were synthesized and charactenzed by X-ray single crystal analysis, IR spectroscopy, ESI-MS, and by solid-state stripping voltammetry. The encapsulation of trans-[Co(tn)2Cl2]+ within the cavity of CB[8] stabilizes the complex toward ligand substitution reactions in aqueous solution. The electrochemical study demonstrates that CB[8] prefers the oxidized species in trans-[Co(tn)2Cl2]+/trans-[Co(tn)2Cl2]0 and trans-[Co(tmO)(tmOH)2]2+/trans-{Co(tmO)(tmOH)2]+ redox couples, but stabilizes the reduced form trans-[Ni(tmOH)2]2+ against the oxidized species. The reversibility of voltammogram shapes evidence that for the inclusion compounds 1-3 electron transfer reactions proceed within the cavity of the host. [ABSTRACT FROM AUTHOR]

The reaction of [(AuCI)2dppm] (dppm = Ph2PCH2PPh2) with PhP(SiMe3)2 and P(SiMe3)3 leads to the formation of the gold cluster compound [Au18(P)2(PPh)4(PHPh)(dppm)6]Cl3 (1). The crystal structure investigation shows a central Au7P2 unit formed by two P centered gold tetrahedra sharing the central gold corner. This central unit is surrounded by a 10-membered Au5P5 ring which, together with the remaining six gold atoms, builds two Au4P rectangular and two Au3P trigonal pyramids. The different structure motifs are connected by the phosphine ligands. The compound has been characterized using microanalysis, IR spectroscopy, ESI-MS, and 31P NMR techniques. Luminescence measurements have also been carried out. [ABSTRACT FROM AUTHOR]

Treatment of [Et4N]2[WSe4] with a 1:1 mixture of AgNO3 and PCy3 (Cy = cyclohexyl) in the absence of iodide afforded a linear trinuclear compound [(μ-WSe4)(AgPCy3)2] (1). A similar reaction in the presence of iodide gave rise to the isolation of the cubanelike compound [(μ3-WSe4)Ag3(PCy3)3(μ3-I)] (2). Treatment of [Et4N]2[WSe4] with Agi in the presence of bidentate phosphine ligands bis(diphenylphosphino)amine (dppa) and bis(diphenylphosphino)-methane (dppm) afforded the tetranuclear compounds [(μ3-WSe4)Ag3(μ-l)(μ-dppa)2] (3) and [(μ3-WSe4)Ag3(μ3-I)-(μ-dppm)2] (4), respectively, which exhibit an open butterfly configuration. A novel hexanuclear cluster compound [(μ3-WSe4)2Ag4(μ-dppm)3] (5) was obtained from interaction of [Et4N]2[WSe4] with AgNO3 and dppm in the absence of iodide source. The above cluster compounds are electrically neutral and air-stable in both solution and the solid state and have been characterized by electronic, infrared, mass, and NMR spectroscopies. The solid-state structures of five cluster compounds have been established by X-ray crystallography. The nonlinear optical properties of compounds 4 and 5 were examined by z-scan techniques with 7 ns pulses at 532 nm. The optical limiting effects of compounds 1, 2, 4, and 5 were determined and compared with related argentoselenometallic compounds. [ABSTRACT FROM AUTHOR]

The coplanar cluster compound [Et4N]4[(μ4-WSe4)Cu4l6] (1) was prepared from reaction of [Et4N]2[WSe4] with 4 equiv of Cul in N,N-dimethylformamide (DMF) solution in the presence of [Et4N]l. Treatment of 1 with pyridine (py) in dry MeCN gave the neutral cluster [(μ4-WSe4)Cu4(py)6l2] (2) in good yield. Recrystallization of 1 from py/i-PrOH resulted in the reorganization of the coplanar WSe4Cu4 core and the formation of a neutral polymeric cluster [(μ3-WOSe3)Cu3(py)3(μ-l)]n (3) containing a nest-shaped OWSe3Cu3 core and a terminal W=O bond. The interaction of cluster 1 with excess PPh3 in CH2Cl2 gave [(μ3-WSe4)Cu3(PPh3)3(μ3-l)] (4) which has a cubanelike SeWSe3Cu3l core. Treatment of 1 with 1 equiv of Cul in dimethyl sulfoxide (DMSO) yielded [Et4N]4[μ5-WSe4)(Cul)5(μ-l)2] (5) which has a crownlike core structure. Treatment of 1 in DMF with 2 equiv of Cul in the presence of py resulted in the formation of a two-dimensional polymeric cluster, [(μ6-WSe4)Cu6l4(py)4]n (6), consisting of an octahedral WSe4Cu6 repeating unit. The solid-state structures of clusters 3, 5, and 6 have been further established by X-ray crystallography. The nonlinear optical properties of 6 have been also investigated. Cluster 6 was found to exhibit good photostability and a large optical limiting effect with the limiting threshold being ca. 0.3 J cm-2. [ABSTRACT FROM AUTHOR]

Examines the preparation and properties of aqua ions. X-ray crystal structures of aqua ions; Chemistry of transition-metal chalcogenic clusters; Role of cuboidal M[sub 4]Q[sub 4] complexes in transition metal chemistry; Increase in the reducing properties of tungsten content.

Examines the crystal structure of phosphorous acid and arsenious acid complexes. Coordination of the ligands to the Pd site of a heterometal cuboidal cluster with the Mo[sub 3]PdS[sub 4][sup 4+]; Crystallization of the complexes; Hydrogen bonds within the complexes.