TeX(4) (X = F, Cl, Br) as Lewis acids - complexes with soft thio- and seleno-ether ligands

TeF(4) reacts with OPR(3) (R = Me or Ph) in anhydrous CH(2)Cl(2) to give the colourless, square based pyramidal 1?:?1 complexes [TeF(4)(OPR(3))] only, in which the OPR(3) is coordinated basally in the solid state, (R = Me: d(Te-O) = 2.122(2) ?; R = Ph: d(Te-O) = 2.1849(14) ?). Variable temperature (19)F{(1)H}, (31)P{(1)H} and (125)Te{(1)H} NMR spectroscopic studies strongly suggest this is the low temperature structure in solution, although the systems are dynamic. The much softer donor ligands SMe(2) and SeMe(2) show a lower affinity for TeF(4), although unstable, yellow products with spectroscopic features consistent with [TeF(4)(EMe(2))] are obtained by the reaction of TeF(4) in neat SMe(2) or via reaction in CH(2)Cl(2) with SeMe(2). TeX(4) (X = F, Cl or Br) causes oxidation and halogenation of TeMe(2) to form X(2)TeMe(2). The Br(2)TeMe(2) hydrolyses in trace moisture to form [BrMe(2)Te-O-TeMe(2)Br], the crystal structure of which has been determined. TeX(4) (X = Cl or Br) react with the selenoethers SeMe(2), MeSe(CH(2))(3)SeMe or o-C(6)H(4)(SeMe)(2) (X = Cl) in anhydrous CH(2)Cl(2) to give the distorted octahedral monomers trans-[TeX(4)(SeMe(2))(2)], cis-[TeX(4){MeSe(CH(2))(3)SeMe}] and cis-[TeCl(4){o-C(6)H(4)(SeMe)(2)}], which have been characterised by IR, Raman and multinuclear NMR ((1)H, (77)Se{(1)H} and (125)Te{(1)H}) spectroscopy, and via X-ray structure determinations of representative examples. Tetrahydrothiophene (tht) can form both 1?:?1 and 1?:?2 Te?:?L complexes. For X = Br, the former has been shown to be a Br-bridged dimer, [Br(3)(tht)Te(μ-Br)(2)TeBr(3)(tht)], by crystallography with the tht ligands anti, whereas the latter are trans-octahedral monomers. Like its selenoether analogue, MeS(CH(2))(3)SMe forms distorted octahedral cis-chelates, [TeX(4){MeS(CH(2))(3)SMe}], whereas the more rigid o-C(6)H(4)(SMe)(2) unexpectedly forms a zig-zag chain polymer in the solid state, [TeCl(4){o-C(6)H(4)(SMe)(2)}](n), in which the dithioether adopts an extremely unusual bridging mode. This is in contrast to the chelating monomer, cis-[TeCl(4){o-C(6)H(4)(SeMe)(2)}], formed with the analogous selenoether and may be attributed to small differences in the ligand chelate bite angles. The wider bite angle xylyl-linked bidentates, o-C(6)H(4)(CH(2)EMe(2))(2) behave differently; the thioether forms cis-chelated [TeX(4){o-C(6)H(4)(CH(2)SMe)(2)}] confirmed crystallographically, whereas the selenoether undergoes C-Se cleavage and rearrangement on treatment with TeX(4), forming the cyclic selenonium salts, [C(9)H(11)Se](2)[TeX(6)]. The tetrathiamacrocycle, [14]aneS(4) (1,4,8,11-tetrathiacyclotetradecane), does not react cleanly with TeCl(4), but forms the very poorly soluble [TeCl(4)([14]aneS(4))](n), shown by crystallography to be a zig-zag polymer with exo-coordinated [14]aneS(4) units linked via alternate S atoms to a cis-TeCl(4) unit. Trends in the (125)Te{(1)H} NMR shifts for this series of Te(iv) halides chalcogenoether complexes are discussed.     

Preparation, characterization, and structural systematics of diphosphane and diarsane complexes of gallium(III) halides

The diphosphane o-C6H4(PMe2)2 reacts with GaX3 (X = Cl, Br, or I) in a 1:1 molar ratio in dry toluene to give trans-[GaX2{o-C6H4(PMe2)2}2][GaX4], the cations of which contain the first examples of six-coordinate gallium in a phosphane complex. The use of a 1:2 ligand/GaCl3 ratio produced [GaCl2{o-C6H4(PMe2)2}][GaCl4], containing a pseudotetrahedral cation, and similar pseudotetrahedral [GaX2{o-C6H4(PPh2)2}][GaX4] complexes are the only products isolated with the bulkier o-C6H4(PPh2)2. On the other hand, Et2P(CH2)2PEt2, which has a flexible aliphatic backbone, formed [(X3Ga)2{mu-Et2P(CH2)2PEt2}], in which the ligand bridges two pseudotetrahedral gallium centers. The diarsane, o-C6H4(AsMe2)2, formed [GaX2{o-C6H4(AsMe2)2}][GaX4], also containing pseudotetrahedral cations, and in marked contrast to the diphosphane analogue, no six-coordinate complexes form; a very rare example where these two much studied ligands behave differently towards a common metal acceptor. The complexes [(I3Ga)2{mu-Ph2As(CH2)2AsPh2}] and [GaX3(AsMe3)] are also described. The X-ray structures of trans-[GaX2{o-C6H4(PMe2)2}2][GaX4] (X = Cl, Br or I), [GaCl2{o-C6H4(PPh2)2}][GaCl4], [GaX2{o-C6H4(AsMe2)2}][GaX4] (X = Cl or I), [(I3Ga)2{mu-Ph2As(CH2)2AsPh2}], and [GaX3(AsMe3)] (X = Cl, Br or I) are reported, and the structural trends are discussed. The solution behavior of the complexes has been explored using a combination of 31P{1H} and 71Ga NMR spectroscopy.     

Transition metal complexes with wide-angle dithio-, diseleno- and ditelluroethers: properties and structural systematics

The ligands o-C(6)H(4)(CH(2)EMe)(2) (E = S or Se) have been prepared and characterised spectroscopically. A systematic study of the coordination chemistry of these, together with the telluroether analogue, o-C(6)H(4)(CH(2)TeMe)(2), with late transition metal centers has been undertaken. The planar complexes [MCl(2){o-C(6)H(4)(CH(2)SMe)(2)}] and [M{o-C(6)H(4)(CH(2)EMe)(2)}(2)](PF(6))(2) (M = Pd or Pt; E = S or Se), the distorted octahedral [RhCl(2){o-C(6)H(4)(CH(2)EMe)(2)}(2)]Y (E = S or Se: Y = PF(6); E = Te: Y = Cl) and [RuCl(2){o-C(6)H(4)(CH(2)EMe)(2)}(2)] (E = S, Se or Te), the dithioether-bridged binuclear [{RuCl(2)(p-cymene)}(2){micro-o-C(6)H(4)(CH(2)SMe)(2)}] and the tetrahedral [M'{o-C(6)H(4)(CH(2)EMe)(2)}(2)]BF(4) (M' = Cu or Ag; E = S, Se or Te) have been obtained and characterised by IR and multinuclear NMR spectroscopy ((1)H, (63)Cu, (77)Se{(1)H}, (125)Te{(1)H} and (195)Pt), electrospray MS and microanalyses. Crystal structures of the parent o-C(6)H(4)(CH(2)SMe)(2) and seven complexes are described, which show three different stereoisomeric forms for the chelated ligands, as well as the first example of a bridging coordination mode in [{RuCl(2)(p-cymene)}(2){micro-o-C(6)H(4)(CH(2)SMe)(2)}]. These studies reveal the consequences of the sterically demanding o-xylyl backbone, which typically leads to unusually obtuse E-M-E chelate angles of approximately 100 degrees .     

Unexpected reactivity and coordination in gallium(III) and indium(III) chloride complexes with geometrically constrained thio- and selenoether ligands

Reaction of GaCl(3) with 1 mol equiv of [14]aneS(4) in anhydrous CH(2)Cl(2) gives the exocyclic chain polymer [GaCl(3)([14]aneS(4))] (1) whose structure confirms trigonal bipyramidal coordination at Ga with a planar GaCl(3) unit. In contrast, using [16]aneS(4) and GaCl(3) or [16]aneSe(4) and MCl(3) (M = Ga or In) in either a 1:1 or a 1:2 molar ratio produces the anion-cation complexes [GaCl(2)([16]aneS(4))][GaCl(4)] (2) and [MCl(2)([16]aneSe(4))][MCl(4)] (M = Ga, 3 and M = In, 4) containing trans-octahedral cations with endocyclic macrocycle coordination. The ligand-bridged dimer [(GaCl(3))(2){o-C(6)H(4)(SMe)(2)}] (5) is formed from a 2:1 mol ratio of the constituents and contains distorted tetrahedral Ga(III). This complex is unusually reactive toward CH(2)Cl(2), which is activated toward nucleophilic attack by polarization with GaCl(3), producing the bis-sulfonium species [o-C(6)H(4)(SMeCH(2)Cl)(2)][GaCl(4)](2) (6), confirmed from a crystal structure. In contrast, the xylyl-based dithioether gives the stable [(GaCl(3))(2){o-C(6)H(4)(CH(2)SEt)(2)}] (8). However, replacing GaCl(3) with InCl(3) with o-C(6)H(4)(CH(2)SEt)(2) preferentially forms the 4:3 In:L complex [(InCl(3))(4){o-C(6)H(4)(CH(2)SEt)(2)}(3)] (9) containing discrete tetranuclear moieties in which the central In atom is octahedrally coordinated to six bridging Cl's, while the three In atoms on the edges have two bridging Cl's, two terminal Cl's, and two mutually trans S-donor atoms from different dithioether ligands. GaCl(3) also reacts with the cyclic bidentate [8]aneSe(2) to form a colorless, extremely air-sensitive adduct formulated as [(GaCl(3))(2)([8]aneSe(2))] (10), while InCl(3) gives [InCl(3)([8]aneSe(2))] (14). Very surprisingly, 10 reacts rapidly with O(2) gas to give initially the red [{[8]aneSe(2)}(2)][GaCl(4)](2) (11) and subsequently the yellow [{[8]aneSe(2)}Cl][GaCl(4)] (12). The crystal structure of the former confirms a dimeric [{[8]aneSe(2)}(2)](2+) dication, derived from coupling of two mono-oxidized {[8]aneE(2)}(+?) cation radicals to form an Se-Se bond linking the rings and weaker transannular 1,5-Se···Se interactions across both rings. The latter (yellow) product corresponds to discrete doubly oxidized {[8]aneSe(2)}(2+) cations (with a primary Se-Se bond across the 1,5-positions of the ring) with a Cl(-) bonded to one Se. Tetrahedral [GaCl(4)](-) anions provide charge balance in each case. These oxidation reactions are clearly promoted by the Ga(III) since [8]aneSe(2) itself does not oxidize in air. The new complexes have been characterized in the solid state by IR and Raman spectroscopy, microanalysis, and X-ray crystallography where possible. Where solubility permits, the solution characteristics have been probed by (1)H, (77)Se{(1)H}, and (71)Ga NMR spectroscopic studies.     

Thio- and seleno-ether complexes with Group 4 tetrahalides and tin tetrachloride: preparation and use in CVD for metal chalcogenide films

Reaction of TiCl(4) or ZrI(4) with the soft, neutral o-C(6)H(4)(CH(2)EMe)(2) (E = S or Se) in anhydrous CH(2)Cl(2) (or toluene) yields the distorted octahedral chelate complexes [MX(4){o-C(6)H(4)(CH(2)EMe)(2)}]. Using Et(2)Se gives [MX(4)(Et(2)Se)(2)] (M = Zr, X = Cl or I; M = Hf, X = I). The Sn(IV) analogues, [SnCl(4){o-C(6)H(4)(CH(2)EMe)(2)}] and [SnCl(4)(Et(2)Se)(2)] were obtained similarly. These complexes have been characterised spectroscopically and analytically, and crystal structures of trans-[SnCl(4)(Et(2)Se)(2)] and some selenonium salts derived as minor by-products from the parent Group 4 complexes are described. The neutral chalcogenoether complexes have been evaluated as single source precursors to ME(2)/ME thin films via LPCVD. [TiCl(4){o-C(6)H(4)(CH(2)EMe)(2)}] leads to the deposition of air and moisture stable TiE(2) films (with no residual Cl). Coverage of the substrate is uniform with platelet growth perpendicular to the surface. The heavier Zr(IV) species do not lead to significant ZrE(2) deposition. On the other hand, LPCVD of [SnCl(4){o-C(6)H(4)(CH(2)SMe)(2)}] leads to deposition of SnS(2) at lower temperatures and SnS at higher temperatures, while [SnCl(4){o-C(6)H(4)(CH(2)SeMe)(2)}] gives rather uneven coatings of SnSe(2). The Et(2)Se derivative, [SnCl(4)(Et(2)Se)(2)] leads to uniform deposition of SnSe(2) with growth perpendicular to the substrate surface. The SnE(2)/SnE films are stable indefinitely to air and moisture. The generation of TiS(2), SnS(2) and SnS in this way are very rare examples of metal sulfide deposition from C-S bond fission within a thioether complex.     

Synthesis, spectroscopic, and structural studies on transition metal complexes involving homoleptic tripodal selenoether and telluroether coordination

The reaction of [MCl2(NCMe)2] (M = Pd or Pt) with 2 molar equiv of MeC(CH2ER)3 (E = Se, R = Me; E = Te, R = Me or Ph) and 2 molar equiv of TlPF6 affords the bis ligand complexes [M(MeC(CH2ER)3)2][PF6]2. The crystal structure of [Pt(MeC(CH2SeMe)3)2][PF6]2 (C16H36F12P2PtSe6, a = 12.272(10) A, b = 18.563(9) A, c = 15.285(7) A, beta = 113.18(3) degrees, monoclinic, P2(1)/n, Z = 4) confirms distorted square planar Se4 coordination at Pt(II), derived from two bidentate tripod selenoethers with the remaining arm not coordinated and directed away from the metal center. Solution NMR studies indicate that these species are fluxional and that the telluroether complexes are rather unstable in solution. The octahedral bis tripod complexes [Ru(MeC(CH2SMe)3)2][CF3-SO3]2 and [Ru(MeC(CH2TePh)3)2][CF3SO3]2 are obtained from [Ru(dmf)6][CF3SO3]3 and tripod ligand in EtOH solution. The thioether complex (C18H36F6O6RuS8, a = 8.658(3) A, b = 11.533(3) A, c = 8.659(2) A, alpha = 108.33(2) degrees, beta = 91.53(3) degrees, gamma = 106.01(2) degrees, triclinic, P1, Z = 1) is isostructural with its selenoether analogue, involving two facially coordinated trithioether ligands in the syn configuration. NMR spectroscopy confirms that this configuration is retained in solution for all of the bis tripod Ru(II) complexes. These low-spin d6 complexes show unusually high ligand field splittings. The hexaselenoether Rh(III) complex [Rh(MeC(CH2SeMe)3)2][PF6]3 was obtained by treatment of [Rh(H2O)6]3+ with 2 molar equiv of MeC(CH2SeMe)3 in aqueous MeOH in the presence of excess PF6- anion, while the iridium(III) analogue [Ir(MeC(CH2SeMe)3)2][PF6]3 was obtained via the reaction of the Ir(I) precursor [IrCl(C8H14)2]2 with the selenoether tripod in MeOH/aqueous HBF4. NMR studies reveal different invertomers in solution for both the Rh and Ir species. The Cu(I) complexes [Cu(MeC(CH2ER)3)2]PF6 were obtained from [Cu(NCMe)4]PF6 and tripod ligand in CH2Cl2 solution. The corresponding Ag(I) species [Ag(MeC(CH2TeR)3)2]CF3SO3 (R = Me or Ph) were obtained from Ag[CF3SO3] and tripod telluroether. In contrast, a similar reaction with 2 molar equiv of MeC(CH2SeMe)3 afforded only the 1:1 complex [Ag(MeC(CH2SeMe)3)]CF3SO3. The structure of this species (C9H18AgF3O3SSe3, a = 8.120(3) A, b = 15.374(3) A, c = 14.071(2) A, beta = 93.86(2) degrees, monoclinic, P2(1)/n, Z = 4) reveals a distorted trigonal planar geometry at Ag(I) derived from one bidentate selenoether and one monodentate selenoether. These units are then linked to adjacent Ag(I) ions to give a one-dimensional linear chain cation.     

Preparation, properties and structures of the first series of organometallic Pt(II) and Pt(IV) complexes with stibine co-ligands

The planar Pt(II) monomers [PtMe2(L-L)] and [(PtMe2)2(L'-L')2] dimers (L-L = R2Sb(CH2)3SbR2, o-C6H4(CH2SbMe2)2; L'-L' = R2SbCH2SbR2; R = Me or Ph) are obtained in good yield via reaction of [PtMe2(SMe2)2] with L-L or L'-L' in benzene. The Pt(iv) stibines, [PtMe3(L-L)I] (L-L = R2Sb(CH2)3SbR2, o-C6H4(CH2SbMe2)2 or 2 x SbPh3, SbMePh2 or SbMe2Ph) are obtained by treatment of [PtMe3I] with L-L in chloroform. These represent the first series of stable Pt(IV) stibine complexes. All of the products have been characterised by 1H, 13C{1H}, 195Pt NMR spectroscopy, electrospray mass spectrometry and analysis. Crystal structure determinations on [PtMe3{R2Sb(CH2)3SbR2}I], [PtMe3{o-C6H4(CH2SbMe2)2}I] and [PtMe3(SbPh3)2I] confirm the distorted octahedral environment at Pt, with fac Me groups and mutually cis Sb donor atoms. The Sb-Pt-Sb angle in the seven-membered chelate ring of the o-C6H4(CH2SbMe2)2 complex is ca. 96 degrees , compared to <90 degrees in the complexes with six-membered chelates. The C1-distibines R2SbCH2SbR2 afford only the dinuclear [(PtMe3)2(mu-R2SbCH2SbR2)(mu-I)2] in which the stibine ligand and two I atoms bridge two Pt atoms giving an edge sharing bioctahedral geometry which has been confirmed by a crystal structure analysis. The Pt(II) species undergo oxidative addition with MeI to give the corresponding Pt(IV) species, while the Pt(IV) species reductively eliminate ethane upon thermolysis.     

Self-Assembly of Ribbons and Frameworks Containing Large Channels Based upon Methylene-Bridged Dithio-, Diseleno-, and Ditelluroethers

Homoleptic copper(I) and silver(I) complexes [M(n)(L-L)(2)(n)()](BF(4))(n)() (M = Cu or Ag; L-L = MeECH(2)EMe; E = S, Se or Te) have been prepared and characterized by analysis, FAB mass spectrometry, and IR and multinuclear NMR spectroscopy ((1)H, (77)Se, (125)Te, (63)Cu and (109)Ag). The single-crystal X-ray structures of [Cu(n)()(MeSeCH(2)SeMe)(2)(n)()](PF(6))(n)() (orthorhombic, P2(1)2(1)2(1), a = 10.879(7) ?, b = 16.073(7) ?, c = 9.19(1) ?, Z = 4) and [Ag(n)()(MeSeCH(2)SeMe)(2)(n)()](BF(4))(n)() (monoclinic, P2(1)/c, a = 14.546(9) ?, b = 14.65(1) ?, c = 30.203(9) ?, Z = 4) reveal extended three-dimensional cationic frameworks in the solid state which contain large cylindrical or rectangular channels accommodating the PF(6)(-) or BF(4)(-) counterions. In contrast, a single-crystal X-ray structure of [Cu(n)()(MeSCH(2)SMe)(2)(n)()](PF(6))(n)().nMeNO(2) (orthorhombic, Pbcn, a = 15.506(3) ?, b = 8.934(2) ?, c = 25.859(3) ?, Z = 8) shows tetrahedral Cu(I) ions coordinated to bridging dithioethers forming an cationic ribbon-like arrangement of 8-membered rings. Adjacent rings are linked by the Cu atoms. Variable temperature NMR studies have been used to probe various exchange processes occurring in solution in these systems.     

Synthesis, spectroscopic and structural properties of hexavalent molybdenum complexes with thio- and seleno-ether ligands

The highly unusual Mo(VI) thioether complexes [MoO(2)X(2)(L-L)][space](X = Cl or Br; L-L = MeS(CH(2))(2)SMe or EtS(CH(2))(2)SEt) were obtained by reaction of MoO(2)X(2) with L-L in rigorously anhydrous CH(2)Cl(2) solution. Similar reaction of MoO(2)Cl(2) with the diselenoether MeSe(CH(2))(2)SeMe gives the very reactive [MoO(2)Cl(2)[MeSe(CH(2))(2)SeMe]] as a yellow solid. These compounds are very moisture sensitive and were characterised by IR, diffuse reflectance UV-vis and multinuclear ((1)H, (13)C[(1)H], (77)Se and (95)Mo) NMR spectroscopy. The data are consistent with distorted 6-coordination at Mo(vi)viatrans X ligands, mutually cis oxo groups and a chelating dithio- or diseleno-ether ligand. Variable temperature (1)H and (13)C[(1)H] NMR data indicate fast pyramidal inversion at the coordinated chalcogen atoms occurs at room temperature, but cooling slows this process to reveal resonances consistent with the meso and dl forms. The (95)Mo NMR spectra are single resonances in the region 200-300 ppm, as expected for Mo(vi) complexes, and show inverse dependence of the chemical shifts upon both halide and chalcogen type. Crystal structures of three of the dithioether complexes are described and provide unequivocal evidence for Mo(vi) thioether coordination, confirming chelation of the dithioether through long Mo-S interactions of ca. 2.7 [Angstrom]. Attempts to extend the range of compounds by using other chalcogenoether ligands failed, indicating that to obtain complexes involving these extremely mis-matched metal ligand combinations requires both the favourable 5-membered chelate ring and small terminal alkyl substituents on the chalcogen.     

Arsenic(III) halide complexes with acyclic and macrocyclic thio- and selenoether coligands: synthesis and structural properties

The preparations of the new complexes [AsBr(3)[MeS(CH(2))(2)SMe]], [AsX(3)([9]aneS(3))] (X = Cl, Br or I; [9]aneS(3) = 1,4,7-trithiacyclononane), [AsCl(3)([14]aneS(4))] ([14]aneS(4) = 1,4,8,11-tetrathiacyclotetradecane), [AsX(3)([8]aneSe(2))] ([8]aneSe(2) = 1,5-diselenacyclooctane), [(AsX(3))(2)([16]aneSe(4))] ([16]aneSe(4) = 1,5,9,13-tetraselenacyclohexadecane), and [(AsBr(3))(2)([24]aneSe(6))] ([24]aneSe(6) = 1,5,9,13,17,21-hexaselenacyclotetracosane) are described. These are obtained from direct reaction of the appropriate AsX(3) and 1 mol equiv of the thio- or selenoether ligand in anhydrous CH(2)Cl(2) (or thf for X = I) solution. The products have been characterized by microanalysis and IR and (1)H NMR spectroscopy. In solution they are extensively dissociated, reflecting the weak Lewis acidity of AsX(3). Reaction of AsX(3) with MeSe(CH(2))(2)SeMe or MeC(CH(2)EMe)(3) (E = S or Se) gave only oils. Treatment of PCl(3) or PBr(3) with Me(2)S, MeE(CH(2))(2)EMe, or [9]aneS(3) failed to give solid complexes, and there was no evidence from NMR spectroscopy for any adduct formation in solution. The crystal structures of the first series of thioether and selenoether complexes of As(III) are described: [AsBr(3)[MeS(CH(2))(2)SMe]], C(4)H(10)AsBr(3)S(2), a = 10.2818(6) A, b = 7.8014(5) A, c = 14.503(1) A, beta = 102.9330(2) degrees, monoclinic, P2(1)/c, Z = 4; [AsI(3)[MeS(CH(2))(2)SMe]], C(4)H(10)AsI(3)S(2), a = 9.1528(1) A, b = 11.5622(2) A, c = 12.0939(2) A, beta = 93.863(1) degrees, monoclinic, P2(1)()/n, Z = 4; [AsCl(3)([9]aneS(3))], C(6)H(12)AsCl(3)S(3), a = 17.520(4) A, b = 17.520(4) A, c = 16.790(7) A, tetragonal, I4(1)cd, Z = 16; [AsCl(3)([14]aneS(4))], C(10)H(20)AsCl(3)S(4), a = 13.5942(2) A, b = 7.7007(1) A, c = 18.1270(3) A, beta = 111.1662(5) degrees, monoclinic, P2(1)()/n, Z = 4; [(AsCl(3))(2)([16]aneSe(4))], C(12)H(24)As(2)Cl(6)Se(4), a = 9.764(3) A, b = 13.164(1) A, c = 10.627(2) A, beta = 114.90(1) degrees, monoclinic, P2(1)()/n, Z = 2; [(AsBr(3))(2)([16]aneSe(4))], C(12)H(24)As(2)Br(6)Se(4), a = 10.1220(1) A, b = 13.4494(2) A, c = 10.5125(2) A, beta = 113.49(2) degrees, monoclinic, P2(1)()/n, Z = 2. [AsBr(3)[MeS(CH(2))(2)SMe]] and [AsI(3)[MeS(CH(2))(2)SMe]] reveal discrete mu(2)-halo As(2)X(6) dimeric structures involving distorted octahedral As(III), with the dithioether ligand chelating. [AsCl(3)([9]aneS(3))] adopts a discrete molecular distorted octahedral geometry with the thioether behaving as a weakly coordinated fac-capping ligand. [AsCl(3)([14]aneS(4))] forms an infinite sheet involving two mu(2)-chloro ligands on each As but bridging to two distinct As centers. Each macrocycle coordinates to two adjacent As centers via one S atom, giving a cis-octahedral Cl(4)S(2) donor set at As(III). The structures of [(AsCl(3))(2)([16]aneSe(4))] and [(AsBr(3))(2)([16]aneSe(4))] adopt 2-dimensional sheet structures with mu(2)-dihalo As(2)X(6) dimers cross-linked by mu(4)-tetraselenoether macrocycles, giving a disorted cis-X(4)Se(2) donor set at each As center. These species are compared with their antimony(III) and bismuth(III) analogues where appropriate.     

Preparation, characterization, and structural systematics of diphosphane and diarsane complexes of indium(III) halides

The ligands o-C6H4(PMe2)2 and o-C6H4(AsMe2)2 (L-L) react with anhydrous InX3 (X = Cl, Br, or I) in a 2:1 InX3/ligand ratio to form [InX2(L-L)][InX4] containing distorted tetrahedral cations, established by X-ray crystal structures for L-L = o-C6H4(PMe2)2 (X = Br or I) and o-C6H4(AsMe2)2 (X = I). IR, Raman, and multinuclear NMR ((1)H, (31)P, (115)In) spectroscopy show that these are the only species present in solution in chlorocarbons and in the bulk solids. The products from reactions in a 1:1 or 1:2 molar ratio are more diverse and include the halide-bridged dimers [In2Cl6{o-C6H4(PMe2)2}2] and [In2X6{o-C6H4(AsMe2)2}2] (X = Cl or Br) and the distorted octahedral cation trans-[InBr2{o-C6H4(PMe2)2}2][InBr4]. The neutral complexes partially rearrange in chlorocarbon solution, with multinuclear NMR spectroscopy revealing [InX4](-) among other species. The iodo complexes trans-[InI2(L-L)2][InI4(L-L)] contain rare examples of six-coordinate anions, as authenticated by an X-ray crystal structure for L-L = o-C6H4(PMe2)2. Two species of formula [In2Cl5(L-L)2]n[InCl4]n (L-L = o-C6H4(PMe2)2 and o-C6H4(AsMe2)2) were identified crystallographically and contain polymeric cations with six-coordinate indium centers bonded to one chelating L-L and a terminal chlorine, linked by alternating single and double chlorine bridges into chains. The complicated chemistry of InX3 with these two rigid chelates is contrasted with that of the flexible diphosphane Et2P(CH2)2PEt2, which forms [In2Cl6{Et2P(CH2)2PEt2}2], and with more sterically demanding o-C6H4(PPh2)2 (Sigl et al. Eur. J. Inorg. Chem. 1998, 203-210). The results also contrasted with those found for GaX3 with the same ligands (Cheng et al. Inorg. Chem. 2007, 46, 7215-7223).     

Cyclotetraphosphinophosphonium ions: synthesis, structures, and pseudorotation

The first derivatives of catenated cyclotetraphosphinophosphonium cations, [(PhP)4PPhMe]+ (8a), [(MeP)4PMe2]+ (8b), [(CyP)4PPh2]+ (8d), [(CyP)4PMe2]+ (8e), [(PhP)4PPh2]+ (8f), [(PhP)4PMe2]+ (8g), are synthesized as trifluoromethanesulfonate (triflate, OSO2CF3-) salts through the reaction of cyclopentaphosphines (PhP)5 (4a) or (MeP)5 (4b) with methyl triflate (MeOTf) or by a net phosphenium ion [PR2+, R = Ph, Me; from R2PCl and trimethylsilyltriflate (Me3SiOTf)] insertion into the P-P bond of either cyclotetraphosphine (CyP)4 (3c) or cyclopentaphosphines (PhP)5 (4a) or (MeP)5 (4b). Although more conveniently prepared from 4a, compound 8a[OTf] can also be formed from (PhP)4 (3a) and MeOTf, and derivatives 8f[OTf] and 8g[OTf] are also accessible through reactions of 3a and R2PCl/Me3SiOTf with R = Ph or Me, respectively. A tetrachlorogallate salt of [(PhP)4PPhtBu]+ (8c) has been synthesized by alkylation of 4a with tBuCl/GaCl3. 31P[1H] NMR parameters for all derivatives of 8 have been determined by iterative simulation of experimental data. Derivatives 8a[OTf], 8b[OTf], 8c[GaCl4], 8e[OTf], 8f[OTf], and 8g[OTf] and have been characterized by X-ray crystallography, showing the most favorable all-trans configuration of substituents for the phosphine centers, thus minimizing steric interactions. Each derivative adopts a unique envelope or twist conformation of C1 symmetry. The effective C2 symmetry observed for 8b, d, e, f, and g in solution, signified by their 31P[1H] NMR AA'BB'X spin systems, implies a rapid conformational exchange for derivatives of 8. The core frameworks of the cations in the solid state are viewed as snapshots of different conformational isomers within the solution-phase pseudorotation process.     

Enhanced reactivity of 2-rhodaoxetanes through a labile acetonitrile ligand

New cationic, square-planar, ethene complexes [(Rbpa)RhI(C2H4)]+ [2a]--[2c]+ (Rbpa = N-alkyl-N,N-di(2-pyridylmethyl)amine; [2a]+: alkyl =R=Me; [2b]+: R = Bu; [2c]+: R = Bz) have been selectively oxygenated in acetonitrile by aqueous hydrogen peroxide to 2-rhoda(III)oxetanes with a labile acetonitrile ligand, [(Rbpa)RhIII(kappa2-C,O-CH2CH2O-)(MeCN)]+, [3a]+-[3c]+. The rate of elimination of acetaldehyde from [(Rbpa)RhIII(kappa2-C,O-CH2CH2O-)(MeCN)]+ increases in the order R = Me< R = Bu< R = Bz. Elimination of acetaldehyde from [(Bzbpa)RhIII(kappa2-C,O-CH2CH2O)(MeCN)]+ [3c]+, in the presence of ethene results in regeneration of ethene complex [(Bzbpa)RhI(C2H4)]+ [2c]+, and closes a catalytic cycle. In the presence of Z,Z-1,5-cyclooctadiene (cod) the corresponding cod complex [(Bzbpa)RhI(cod)]+ [6c]+ is formed. Further oxidation of [3c]+ by H2O2 results in the transient formylmethyl-hydroxy complex [(Bzbpa)RhIII(OH)[kappa1-C-CH2C(O)H]]+ [5c]+.     

Spontaneous formation of heteroligated PtII complexes with chelating hemilabile ligands

The spontaneous formation of the heteroligated complex [PtCl(kappa(2)-Ph(2)PCH(2)CH(2)SMe)(Ph(2)PCH(2)CH(2)SPh)]Cl (8 a) by a novel ligand rearrangement process has been observed. By using the weak-link approach, the relative arrangement of the alkyl and aryl groups can be controlled by abstraction of chloride from 8 a to form the closed complex [Pt(kappa(2)-Ph(2)PCH(2)CH(2)SMe)(kappa(2)-Ph(2)PCH(2)CH(2)SPh)][BF(4)](2) (5) and reopening using halide ions to form semi-open complexes [PtX(kappa(2)-Ph(2)PCH(2)CH(2)SMe)(Ph(2)PCH(2)CH(2)SPh)]BF(4) (8 b; X=Cl(-)) and (8 c; X=I(-)). Analogous procedures using Ph(2)PCH(2)CH(2)SMe and 1,4-(Ph(2)PCH(2)CH(2)S)(2)C(6)H(4) lead to heteroligated bimetallic complexes 7 and 9, illustrating that this ligand rearrangement process can be used as a tool for the assembly of complementary metallosupramolecular structures.     

Self-assembly of luminescent Sn(IV)/Cu/S clusters using metal thiolates as metalloligands

Through the use of (Bu4N)2[Sn3S4(edt)3] (edt=SCH2CH2S(2-)) and Sn(SPh)4 as metalloligands, three neutral compounds have been obtained: [(Ph3P) 2Cu] 2SnS(edt)(2).2CH2Cl2.H2O (1a), [(Ph3P) 2Cu]2SnS(edt)2.2DMF.H2O (1b), and [(Ph3P)Cu] 2Sn(SPh)(6).3H 2O (2). Single-crystal X-ray diffraction studies revealed that compounds 1a and 1b contain the same neutral butterfly-like [(Ph3P)2Cu]2SnS(edt)2 cluster, which consists of one central SnS 5 dreich trigonal bipyramid sharing one vertex and two sides with two slightly distorted CuS 2P2 tetrahedrons. Compound 2 has a linear [(Ph3P)Cu]2Sn(SPh)6 cluster that is composed of a central distorted SnS 6 octahedron sharing two opposite planes with two slightly distorted CuS 3P tetrahedrons. Compound 1a exhibited an emission at 568 nm (tau=12.86 micros) in the solid state, while in CH 2Cl 2 solution, 1a exhibited a green emission at 534 nm (tau=4.75 micros). Compound 2 showed an intense red emission at 696 nm (tau=3.64 micros) upon excitation at 307 nm in the solid state.     

Di- and tri-alkylphosphine adducts of S-donor palladacycles as catalysts in the Suzuki coupling of aryl chlorides

The reaction of tricyclohexylphosphine with the S-based palladacycle [(Pd(mu-OAc)(kappa2-S,C-C(6)H(4)CH(2)SMe))(2)] gives several products, regardless of stoichiometry, one of which, [Pd(kappa1-OAc)(eta1-C(6)H(4)CH(2)SMe)(PCy3)2], has been characterised crystallographically. Despite this, catalysts formed in situ from di- and tri-alkylphosphines and [(Pd(mu-OAc)(kappa2-S,C-C(6)H(4)CH(2)SMe))2] show excellent activity in the Suzuki coupling of a range of deactivated, non-activated and activated aryl chloride substrates.     

Experimental investigations and ab initio studies of selenium(II) dialkanethiolates, Se(SR)2

Selenium(II) dimethanethiolate, Se(SMe)(2), was synthesized by reaction of SeO(2) with HSMe. Basic spectroscopic data for Se(SMe)(2) and selenium(II) bis(2-methyl-2-propanethiolate), Se(S(t)Bu)(2), were recorded and interpreted with the support of ab initio calculations. Both compounds are thermodynamically unstable relatively to selenium and the corresponding disulfide. The UV/vis spectra of both compounds are qualitatively similar, the two bands being attributed to n(Se)-sigma*(Se-S) transitions. The bands at 369 and 397 cm(-1) in the IR spectra of Se(SMe)(2) and Se(S(t)Bu)(2), respectively, are assigned to nu(as)(SeS(2)). The (77)Se NMR shifts of Se(SMe)(2)(784 ppm) and Se(S(t)Bu)(2)(556 ppm) differ substantially from each other and show positive temperature gradients. Calculations at the GIAO-HF/962+(d) level reproduced the difference of the (77)Se NMR chemical shifts between Se(SMe)(2) and Se(S(t)Bu)(2). At the same level, the effect of conformational changes on (77)Se shifts were studied for Se(SMe)(2). In the solid state Se(SMe)(2) forms long intermolecular SeS contacts while Se(S(t)Bu)(2) does not. Both compounds exhibit anti-conformations of the methyl and tert-butyl groups with respect to the SeS(2) plane. MP2/LANL2DZ(d) geometry optimizations, single point energy and frequency calculations performed for Se(SMe)(2) show, that syn- (C(s)) and anti-conformers (C(2)) represent minima on the potential energy surface, the latter being by 8 kJ mol(-1) lower in energy than the former. Both conformers are stabilized by intramolecular pi-type n(S(1))-sigma*(Se-S(2)) orbital interactions. The energy of the transition state for the mutual conversion of the two conformers was calculated to be 31 kJ mol(-1) above that of the syn conformer, allowing a rapid interconversion of the two conformers at room temperature. Intermolecular interactions between Se(SMe)(2) molecules were also studied by means of calculations at the MP2/LANL2DZ(d) level. For Se(S(t)Bu)(2) MP2/LANL2DZ(d) geometry optimizations and single point energy calculations revealed a C(2)-symmetric anti- and a C(1) symmetric syn-conformer, the latter being 21 kJ mol(-1) higher in energy than the former. Se(SMe)(2) and Se(S(t)Bu)(2) exchange thiolate groups with other selenium(II) dithiolates, tellurium(II) dithiolates and with thiols, if catalytic amounts of p-CH(3)C(6)H(4)SO(3)H are added.     

Syntheses and X-ray structures of monocyclic,bicyclic, and spirocyclic gallium and indium boraamidinates

The reactions of [Li(2)[PhB(N(t)Bu)(2)]](2) with GaCl(3) in various stoichiometries yield [Li(thf)(4)][PhB(mu-N(t)Bu)(2)GaCl(2) x GaCl(3)] (1), [PhB(mu-N(t)Bu)(2)GaCl](2) (2), and [mu-Li(OEt(2))[PhB(N(t)Bu)(2)]Ga] (3a), a series of complexes in which the three chloride ligands are successively replaced by the dianion [PhB(N(t)Bu)(2)](2-). The X-ray structures of 1, 2, and 3a show that the boraamidinate ligand adopts an N,N'-chelating mode. In the ion-separated complex 1, one of the nitrogen atoms is coordinated to a GaCl(3) molecule. The related indium complexes [mu-LiCl(thf)(2)][PhB(mu-N(t)Bu)(2)InCl](2) (4) and [mu-Li(OEt(2))[PhB(mu-N(t)Bu)(2)]In] (3b) were obtained in a similar manner. Complex 4 is the indium analogue of 2 with the incorporation of a bissolvated LiCl molecule. In 3a and 3b the spirocyclic [[PhB(mu-N(t)Bu)(2)](2)M](-) (M = Ga, In) anions are N,N'-chelated to the [Li(OEt(2))](+) counterion. Prolonged reactions result in the formation of [PhB(mu-N(t)Bu)(2)GaCl][(t)BuN(H)GaCl(2)] (5) and [[PhB(mu-N(t)Bu)(2)InCl][(t)BuN(H)InCl(2)][mu-LiCl(OEt(2))(2)]] (6), respectively. The X-ray structures of 5 and 6 reveal bicyclic structures which formally involve the entrapment of the monomers (t)BuN(H)MCl(2) by a four-membered BN(2)M ring (M = Ga, In). The synthesis and X-ray structure of Cl(2)Ga[mu-N(H)(t)Bu](2)GaCl(2) are also reported.     

Novel hydridoirida-beta-diketones containing small molecules, CO, or ethylene: their behavior in coordinating solvents such as dimethylsulfoxide or acetonitrile

New hydridoirida-beta-diketones [IrH[(PPh2(o-C6H4CO))2H](CO)]ClO4 2 and [IrH[(PPh2(o-C6H4CO))2H](olefin)]BF4 (olefin = C2H4, 5; 1-hexene, 10) have been prepared. These complexes may afford new diacylhydridoiridium(III) derivatives. In chloroform solution, complex 2 is in equilibrium with the deprotonated diacylhydride trans-[IrH(PPh2(o-C6H4CO))2(CO)] complex 3. In DMSO, deprotonation of 2 occurs to yield the kinetically favored product 3, which isomerizes to the thermodynamically favored complex cis-[IrH(PPh2(o-C6H4CO))2(CO)] 4. Reprotonation of 4 with HBF4 in chlorinated solvents gives the cation in 2. In coordinating solvents such as dimethyl sulfoxide or acetonitrile, complex 5 undergoes displacement of ethylene to afford [IrH{(PPh2(o-C6H4CO))2H](L)]BF4 (L = DMSO, 7; CH3CN, 9). Complexes 5 and 7 undergo deprotonation by NEt3 to give the corresponding diacylhydrides. The ethylene complex gives only trans-[IrH(PPh2(o-C6H4CO))2(C2H4)] 6, while the dimethyl sulfoxide derivative affords a mixture of trans- and cis-[IrH(PPh2(o-C6H4CO))2(DMSO)] 8. Complex 10 shows inhibited alkene rotation around the Ir-olefin axis. All of the complexes were fully characterized spectroscopically. Single-crystal X-ray diffraction analysis was performed on complexes 3, 4, and 9. The 13C NMR and X-ray data point to a carbenoid character in the carbon atoms bonded to iridium in the irida--diketone fragment, so that it can be considered as an acyl(hydroxycarbene) moiety.     

(Fluoren-9-ylidene)methanedithiolato complexes of gold: synthesis, luminescence, and charge-transfer adducts

Piperidinium 9H-fluorene-9-carbodithioate and its 2,7-di-tert-butyl-substituted analogue [(pipH)(S(2)CCH(C(12)H(6)R(2)-2,7)), R = H (1a), t-Bu (1b)] and 2,7-bis(octyloxy)-9H-fluorene-9-carbodithioic acid [HS(2)CCH(C(12)H(6)(OC(8)H(17))(2)-2,7), 2] and its tautomer [2,7-bis(octyloxy)fluoren-9-ylidene]methanedithiol [(HS)(2)C=C(C(12)H(6)(OC(8)H(17))(2)-2,7), 3] were employed for the preparation of gold complexes with the (fluoren-9-ylidene)methanedithiolato ligand and its substituted analogues. The gold(I) compounds Q(2)[Au(2)(mu-kappa(2)-S,S-S(2)C=C(C(12)H(6)R(2)-2,7))(2)], where Q(+) = PPN(+) or Pr(4)N(+) for R = H (Q(2)4a) or Q(+) = Pr(4)N(+) for R = OC(8)H(17) [(Pr(4)N)(2)4c], were synthesized by reacting Q[AuCl(2)] with 1a or 2 (1:1) and excess piperidine or diethylamine. Complexes of the type [(Au(PR'3))(2)(mu-kappa(2)-S,S-S(2)C=C(C(12)H(6)R(2)-2,7))(2)] with R = H and R' = Me (5a), Et (5b), Ph (5c), and Cy (5d) or R = t-Bu and R' = Me (5e), Et (5f), Ph (5g), and Cy (5h) were obtained by reacting [AuCl(PR'(3))] with 1a,b (1:2) and piperidine. The reactions of 1a,b or 2 with Q[AuCl(4)] (2:1) and piperidine or diethylamine gave Q[Au(kappa(2)-S,S-S(2)C=C(C(12)H(6)R(2)-2,7))(2)] with Q(+) = PPN(+) for R = H [(PPN)6a], Q(+) = PPN(+) or Bu(4)N(+) for R = t-Bu (Q6b), and Q(+) = Bu(4)N(+) for R = OC(8)H(17) [(Bu(4)N)6c]. Complexes Q6a-c reacted with excess triflic acid to give [Au(kappa(2)-S,S-S(2)C=C(C(12)H(6)R(2)-2,7))(kappa(2)-S,S-S(2)CCH(C(12)H(6)R(2)-2,7))] [R = H (7a), t-Bu (7b), OC(8)H(17) (7c)]. By reaction of (Bu(4)N)6b with PhICl(2) (1:1) the complex Bu(4)N[AuCl(2)(kappa(2)-S,S-S(2)C=C(C(12)H(6)(t-Bu)(2)-2,7))] [(Bu(4)N)8b] was obtained. The dithioato complexes [Au(SC(S)CH(C(12)H(8)))(PCy(3))] (9) and [Au(n)(S(2)CCH(C(12)H(8)))(n)] (10) were obtained from the reactions of 1a with [AuCl(PCy(3))] or [AuCl(SMe(2))], respectively (1:1), in the absence of a base. Charge-transfer adducts of general composition Q[Au(kappa(2)-S,S-S(2)C=C(C(12)H(6)R(2)-2,7))(2)].1.5TCNQ.xCH(2)Cl(2) [Q(+) = PPN(+), R = H, x = 0 (11a); Q(+) = PPN(+), R = t-Bu, x = 2 (11b); Q(+) = Bu(4)N(+), R = OC(8)H(17), x = 0 (11c)] were obtained from Q6a-c and TCNQ (1:2). The crystal structures of 5c.THF, 5e.(2)/(3)CH(2)Cl(2), 5g.CH(2)Cl(2), (PPN)6a.2Me(2)CO, and 11b were solved by X-ray diffraction studies. All the gold(I) complexes here described are photoluminescent at 77 K, and their emissions can be generally ascribed to LMMCT (Q(2)4a,c, 5a-h, 10) or LMCT (9) excited states.