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1.
The reactions of scandium atoms and O(2) have been reinvestigated using matrix isolation infrared spectroscopy and density functional theory calculations. A series of new oxygen-rich scandium oxide/dioxygen complexes were prepared and characterized. The ground state scandium atoms react with dioxygen to form OSc(eta(2)-O(3)), a side-on bonded scandium monoxide-ozonide complex. The OSc(eta(2)-O(3)) complex rearranges to a more stable Sc(eta(2)-O(2))(2) isomer under visible light irradiation, which is characterized to be a side-on bonded superoxo scandium peroxide complex. The homoleptic trisuperoxo scandium complex, Sc(eta(2)-O(2))(3), and the superoxo scandium bisozonide complex, (eta(2)-O(2))Sc(eta(2)-O(3))(2), are also formed upon sample annealing. The Sc(eta(2)-O(2))(3) complex is determined to have a D(3h) symmetry with three equivalent side-on bonded superoxo ligands around the scandium atom. The (eta(2)-O(2))Sc(eta(2)-O(3))(2) complex has a C(2) symmetry with two equivalent side-on bonded O3 ligands and one side-on bonded superoxo ligand. 相似文献
2.
The reaction of [Sn(NMe(2))(2)](2) (1) with 4 equiv of HOCH(2)CMe(3) (HONep) leads to the isolation of [Sn(ONep)(2)](infinity) (2). Each Sn atom is four coordinated with mu-ONep ligands bridging the metal centers; however, if the free electrons of the Sn(II) metal center are considered, each Sn center adopts a distorted trigonal bipyramidal (TBP) geometry. Through (119)Sn NMR experiments, the polymeric compound 2 was found to be disrupted into smaller oligomers in solution. Titration of 2 with H(2)O led to the identification of two unique hydrolysis products characterized by single-crystal X-ray diffraction as Sn(5)(mu(3)-O)(2)(mu-ONep)(6) (3) and Sn(6)(mu(3)-O)(4)(mu-ONep)(4) (4). Compound 3 consists of an asymmetrical molecule that has five Sn atoms arranged in a square-based pyramidal geometry linked by four basal mu-ONep ligands, two facial mu(3)-O, and two facial mu-ONep ligands. Compound 4 was solved in a novel octahedral arrangement of six Sn cations with an asymmetric arrangement of mu(3)-O and mu-ONep ligands that yields two square base pyramidal and four pyramidal coordinated Sn cations. These compounds were further identified by multinuclear ((1)H, (13)C, (17)O, and (119)Sn) solid-state MAS and high resolution, solution NMR experiments. Because of the complexity of the compounds and the accessibility of the various nuclei, 2D NMR experiments were also undertaken to elucidate the solution behavior of these compounds. On the basis of these studies, it was determined that while the central core of the solid-state structures of 3 and 4 is retained, dynamic ligand exchange leads to more symmetrical molecules in solution. Novel products 3 and 4 lend structural insight into the stepwise hydrolysis of Sn(II) alkoxides. 相似文献
3.
The doubly bridged pyridine-2-thionate (pyS) dimolybdenum complex [Mo(eta(3)-C(3)H(5))(CO)(2)](2)(mu-eta(1),eta(2)-pyS)(2) (1) is accessible by the reaction of [Mo(eta(3)-C(3)H(5))(CO)(2)(CH(3)CN)(2)Br] with pySK in methanol at room temperature. Complex 1 reacts with piperidine in acetonitrile to give the complex [Mo(eta(3)-C(3)H(5))(CO)(2)(eta(2)-pyS)(C(5)H(10)NH)] (2). Treatment of 1 with 1,10-phenanthroline (phen) results in the formation of complex [Mo(eta(3)-C(3)H(5))(CO)(2)(eta(1)-pyS)(phen)] (3), in which the pyS ligand is coordinated to Mo through the sulfur atom. Four conformational isomers, endo,exo-complexes [Mo(eta(3)-C(3)H(5))(CO)(eta(2)-pyS)(eta(2)-diphos)] (diphos = dppm, 4a-4d; dppe, 5a-5d), are accessible by the reactions of 1 with dppm and dppe in refluxing acetonitrile. Homonuclear shift-correlated 2-D (31)P((1)H)-(31)P((1)H) NMR experiments of the mixtures 4a-4d have been employed to elucidate the four stereoisomers. The reaction of 4 and pySK or [Mo(CO)(3)(eta(1)-SC(5)H(4)NH)(eta(2)-dppm)] (6) and O(2) affords allyl-displaced seven-coordinate bis(pyridine-2-thionate) complex [Mo(CO)(eta(2)-pyS)(2)(eta(2)-dppm)] (7). All of the complexes are identified by spectroscopic methods, and complexes 1, 5d, 6, and 7 are determined by single-crystal X-ray diffraction. Complexes 1 and 5d crystallize in the orthorhombic space groups Pbcn and Pbca with Z = 4 and 8, respectively, whereas 6 belongs to the monoclinic space group C2/c with Z = 8 and 7 belongs to the triclinic space group Ponemacr; with Z = 2. The cell dimensions are as follows: for 1, a = 8.3128(1) A, b = 16.1704(2) A, c = 16.6140(2) A; for 5d, a = 17.8309(10) A, b = 17.3324(10) A, c = 20.3716(11) A; for 6, a = 18.618(4) A, b = 16.062(2) A, c = 27.456(6) A, beta = 96.31(3) degrees; for 7, a = 9.1660(2) A, b = 12.0854(3) A, c = 15.9478(4) A, alpha = 78.4811(10) degrees, beta = 80.3894(10) degrees, gamma = 68.7089(11) degrees. 相似文献
4.
5.
Oxidative addition of the sulfur-sulfur bond of 2,2'-pyridine disulfide (C(5)H(4)NS-SC(5)H(4)N) with L(3)W(CO)(3) [L = pyridine, (1)/(3)CHPT; CHPT = cycloheptatriene] in methylene chloride solution yields the seven-coordinate W(II) thiolate complex W(eta(2)-mp)(2)(CO)(3) (mp = monoanion of 2-mercaptopyridine). This complex undergoes slow further oxidative addition with additional pyridine disulfide, yielding W(eta(2)- mp)(4). Reaction of W(eta(2)-mp)(2)(CO)(3) with NO results in quantitative formation of the six-coordinate W(0) complex W(eta(2)-mp)(2)(NO)(2). Reaction of W(eta(2)-mp)(2)(CO)(3) with NO in the presence of added pyridine disulfide yields the seven-coordinate W(II) nitrosyl complex W(eta(2)-mp)(3)(NO) as well as W(eta(2)-mp)(2)(NO)(2) and trace amounts of W(eta(2)-mp)(4). The complex W(eta(2)-mp)(3)(NO) is formed during the course of the reaction and not by reaction of W(eta(2)-mp)(4) or W(eta(2)-mp)(2)(NO)(2) with NO under these conditions. The crystal structures of W(eta(2)- mp)(2)(CO)(3), W(eta(2)-mp)(2)(NO)(2), and W(eta(2)-mp)(3)(NO) are reported. 相似文献
6.
Ethylenediamine (en) solutions of [eta(4)-P(7)M(CO)(3)](3)(-) ions [M = W (1a), Mo (1b)] react under one atmosphere of CO to form microcrystalline yellow powders of [eta(2)-P(7)M(CO)(4)](3)(-) complexes [M = W (4a), Mo (4b)]. Compounds 4 are unstable, losing CO to re-form 1, but are highly nucleophilic and basic. They are protonated with methanol in en solvent giving [eta(2)-HP(7)M(CO)(4)](2)(-) ions (5) and are alkylated with R(4)N(+) salts in en solutions to give [eta(2)-RP(7)M(CO)(4)](2)(-) complexes (6) in good yields (R = alkyl). Compounds 5 and 6 can also be prepared by carbonylations of the [eta(4)-HP(7)M(CO)(3)](2)(-) (3) and [eta(4)-RP(7)M(CO)(3)](2)(-) (2) precursors, respectively. The carbonylations of 1-3 to form 4-6 require a change from eta(4)- to eta(2)-coordination of the P(7) cages in order to maintain 18-electron configurations at the metal centers. Comparative protonation/deprotonation studies show 4 to be more basic than 1. The compounds were characterized by IR and (1)H, (13)C, and (31)P NMR spectroscopic studies and microanalysis where appropriate. The [K(2,2,2-crypt)](+) salts of 5 were characterized by single crystal X-ray diffraction. For 5, the M-P bonds are very long (2.71(1) ?, average). The P(7)(3)(-) cages of 5 are not displaced by dppe. The P(7) cages in 4-6 have nortricyclane-like structures in contrast to the norbornadiene-type geometries observed for 1-3. (31)P NMR spectroscopic studies for 5-6 show C(1) symmetry in solution (seven inequivalent phosphorus nuclei), consistent with the structural studies for 5, and C(s)() symmetry for 4 (five phosphorus nuclei in a 2:2:1:1:1 ratio). Crystallographic data for [K(2,2,2-crypt)](2)[eta(2)-HP(7)W(CO)(4)].en: monoclinic, space group C2/c, a = 23.067(20) ?, b = 12.6931(13) ?, c = 21.433(2) ?, beta = 90.758(7) degrees, V = 6274.9(10) ?(3), Z = 4, R(F) = 0.0573, R(w)(F(2)) = 0.1409. For [K(2,2,2-crypt)](2)[eta(2)-HP(7)Mo(CO)(4)].en: monoclinic, space group C2/c, a = 22.848(2) ?, b = 12.528(2) ?, c = 21.460(2) ?, beta = 91.412(12) degrees, V = 6140.9(12) ?(3), Z = 4, R(F) = 0.0681, R(w)(F(2)) = 0.1399. 相似文献
7.
Antimony compounds that feature multidentate aryloxide ligands, namely [eta4-N(o-C6H4O)3]Sb(OSMe2), {{[eta3-N(o-C6H4OH)(o-C6H4O)2]Sb}2(mu2-O)}2, and {[eta3-PhN(o-C6H4O)2]Sb}4(mu3-O)2 have been synthesized from N(o-C6H4OH)3 and PhN(o-C6H4OH)2 and structurally characterized by X-ray diffraction. While [eta4-N(o-C6H4O)3]Sb(OSMe2) exists as a discrete mononuclear species, the oxo complexes {{[eta3-N(o-C6H4OH)(o-C6H4O)2]Sb}2(mu2-O)}2 and {[eta3-PhN(o-C6H4O)2]Sb}4(micro3-O)2 are multinuclear. Specifically, the dinuclear fragment {[eta3-N(o-C6H4OH)(o-C6H4O)2]Sb}2(mu2-O)} exists in a dimeric form due to the bridging oxo ligand participating in an intermolecular hydrogen bonding interaction, while the dinuclear fragment {[eta3-PhN(o-C6H4O)2]Sb}2(mu-O) exists in a dimeric form due to the bridging oxo ligand serving as a donor to the antimony of a second fragment. The structures of {{[eta3-N(o-C6H4OH)(o-C6H4O)2]Sb}2(mu2-O)}2 and {[eta3-PhN(o-C6H4O)2]Sb}4(mu3-O)(2), therefore, indicate that an oxo ligand bridging two Sb(III) centers is sufficiently electron rich to serve as both an effective hydrogen bond acceptor and as a ligand for an additional Sb(III) center. 相似文献
8.
Mohler DL Shell JR Coonce JG Mirandi JL Riera L Cuesta L Pérez J 《The Journal of organic chemistry》2007,72(23):8755-8759
DNA damage by MoCH3(eta3-allyl)(CO)2(phen) complexes has been shown to occur by two mechanisms: by backbone cleavage via the abstraction of H1' and/or H5' from the deoxyribose moiety and by base modification, resulting in G-specific cleavage via the formation of base-labile residues methylguanine, methoxyguanine, and 8-oxo-G. 相似文献
9.
Dioxygen addition to the 16-electron complexes [OsX(P-P)2]+ (3) gives the dioxygen adducts [OsCl(eta 2-O2)(P-P)2]+ (3), which in turn react with HCl gas to give the novel osmium(IV) oxo complexes trans-[OsX(O)(P-P)2]+ (5) (X = Cl, Br; P-P = 1,2-bis(dicyclohexylphosphino)ethane (dcpe), 1,2-bis(diethylphosphino)ethane (depe), 1,2-bis((2R,5R)-2,5-dimethylphospholano)benzene (Me-duphos)). The complexes [OsX(dcpe)2]+ (X = Cl, Br) (3) are studied by X-ray crystallography and are shown to have a "Y-shaped" coordination geometry in the equatorial plane. The X-ray structural analysis of [OsCl(eta 2-O2)(dcpe)2]+ (4a) reveals an exceptionally short O-O bond (1.315(5) A). trans-[OsCl(O)(dcpe)2]+ (5a), the first oxo complex of osmium(IV) investigated crystallographically, exhibits a long Os-O distance of 1.834(3) A. The reactivity of 4 and 5 as oxidants is described. The dioxygen complex 4a transfers one oxygen atom to PPh3 (to give Ph3PO) or oxidizes iodide ions to triiodide ions in the presence of anhydrous HCl. In both reactions, the corresponding oxo species 5a is quantitatively formed as the only metal-containing product. Oxo complexes 5 are surprisingly stable and unreactive toward standard reducing agents such as phosphines. 相似文献
10.
The reactions of the binuclear oxomolybdenum(V) complex [Cl(2)(O)Mo(&mgr;-OEt)(2)(&mgr;-HOEt)Mo(O)Cl(2)] (1) with Me(3)Si(allyl) and SbF(3) produce the compounds [Mo(6)O(6)Cl(6)(&mgr;(3)-O)(2)(&mgr;(2)-OEt)(6)(&mgr;(2)-Cl)(2)] (2) and [Mo(8)O(8)Cl(6)(&mgr;(3)-O)(4)(OH)(2)(&mgr;(2)-OH)(4)(&mgr;(2)-OEt)(4)(HOEt)(4)] (3), respectively. Treatment of 1 with the Lewis base PMe(3) affords the tetrameric complex [Mo(4)O(4)Cl(4)(&mgr;(2)-OEt)(4)(HOEt)(2)(&mgr;(3)-O)(2)] (4), which represents another link in the chain of clusters produced by the reactions of 1 and simulating the build-up of polymeric molybdenum oxides by sol-gel methods. The crystal structure of 4 has been determined [C(12)H(32)Cl(4)Mo(4)O(12), triclinic, P&onemacr;, a = 7.376(2) ?, b = 8.807(3) ?, c = 11.467(4) ?, alpha = 109.61(1) degrees, beta = 92.12(3) degrees, gamma = 103.75(2) degrees, Z = 1]. By contrast, reaction of 1 with the nitrogen base NEt(3), followed by treatment with [PPN]Cl.2H(2)O ([PPN](+) = [Ph(3)P=N=PPh(3)](+)), gives the complex [PPN](+)[Et(3)NH](+)[Cl(2)(O)Mo(&mgr;(2)-O)(2)Mo(O)Cl(2)](2)(-) (6) in 90% yield. Its crystal structure [C(36)H(30)Cl(4)MoNOP(2), triclinic, Pna2(1), a = 21.470(6) ?, b = 16.765(2) ?, c = 9.6155(14) ?, alpha = 90 degrees, beta = 90 degrees, gamma = 90 degrees, Z = 16] includes the anion [Cl(2)(O)Mo(&mgr;(2)-O)(2)Mo(O)Cl(2)](2)(-), which is a charged derivative of the species forming the gels in sol-gel processes starting from chloromolybdenum ethoxides. Furthermore, compound 1 is found to be catalytically active in esterification and dehydration reactions of alcohols. 相似文献
11.
12.
Figuerola A Tangoulis V Ribas J Hartl H Brüdgam I Maestro M Diaz C 《Inorganic chemistry》2007,46(26):11017-11024
The synthesis, crystal structure, and magnetic properties of two trinuclear oxo-centered carboxylate complexes are reported and discussed: [Cr3(mu3-O)(mu2-PhCOO)6(H2O)3]NO3.4H2O.2CH3OH (1) and [Cr3(mu3-O)(mu2-PhCOO)2(mu2-OCH2CH3)2(bpy)2(NCS)3] (2). For both complexes the crystal system is monoclinic, with space group C2/c for 1 and P1/n for 2. The structure of complex 1 consists of discrete trinuclear cations, associated NO3- anions, and lattice methanol and water molecules. The structure of complex 2 is built only by neutral discrete trinuclear entities. The most important feature of 2 is the unusual skeleton of the [Cr3O] core due to the lack of peripheral bridging ligands along one side of the triangular core, which is unique among the structurally characterized (mu3-oxo)trichromium(III) complexes. Magnetic measurements were performed in the 2-300 K temperature range. For complex 1, in the high-temperature region (T > 8 K), experimental data could be satisfactorily reproduced by using an isotropic exchange model, H = -2J12S1S2 - 2J13S1S3 - 2J23S2S3 (J12 = J13 = J23) with Jij = -10.1 cm(-1), g = 1.97, and TIP = 550 x 10(-6) emu mol(-1). The antisymmetric exchange interaction plays an important role in the magnetic behavior of the system, so in order to fit the experimental magnetic data at low temperature, a new magnetic model was used where this kind of interaction was also considered. The resulting fitting parameters are the following: Gzz = 0.25 cm(-1), delta = 2.5 cm(-1), and TIP = 550 x 10(-6) emu mol(-1). For complex 2, the experimental data could be satisfactorily reproduced by using an isotropic exchange model, H = -2J1(S1S2 + S1S3) - 2J2(S2S3) with J1 = -7.44 cm(-1), J2 = -51.98 cm(-1), and g = 1.99. The magnetization data allows us to deduce the ground term of S = 1/2, characteristic of equilateral triangular chromium(III) for complex 1 and S = 3/2 for complex 2, which is confirmed by EPR measurements. 相似文献
13.
Casey CP Boller TM Kraft S Guzei IA 《Journal of the American Chemical Society》2002,124(44):13215-13221
Hydride abstraction from C(5)Me(5)(CO)(2)Re(eta(2)-PhC triple bond CCH(2)Ph) (1) gave a 3:1 mixture of eta(3)-propargyl complex [C(5)Me(5)(CO)(2)Re(eta(3)-PhCH-C triple bond CPh)][BF(4)] (5) and eta(2)-1-metalla(methylene)cyclopropene complex [C(5)Me(5)(CO)(2)Re(eta(2)-PhC-C=CHPh)][BF(4)] (6). Observation of the eta(2)-isomer requires 1,3-diaryl substitution and is favored by electron-donating substituents on the C(3)-aryl ring. Interconversion of eta(3)-propargyl and eta(2)-1-metalla(methylene)cyclopropene complexes is very rapid and results in coalescence of Cp (1)H NMR resonances at about -50 degrees C. Protonation of the alkynyl carbene complex C(5)Me(5)(CO)(2)Re=C(Ph)C triple bond CPh (22) gave a third isomer, the eta(3)-benzyl complex [C(5)Me(5)(CO)(2)Re[eta(3)(alpha,1,2)-endo,syn-C(6)H(5)CH(C triple bond CC(6)H(5))]][BF(4)] (23) along with small amounts of the isomeric complexes 5 and 6. While 5 and 6 are in rapid equilibrium, there is no equilibration of the eta(3)-benzyl isomer 23 with 5 and 6. 相似文献
14.
Exposing [Bi(OR)3(toluene)]2 (1, R = OC6F5) to different solvents leads to the formation of larger polymetallic bismuth oxo alkoxides via ether elimination/oligomerization reactions. Three different compounds were obtained depending upon the conditions: Bi4(mu 4-O)(mu-OR)6(mu 3-OBi(mu-OR)3)2(C6H5CH3) (2), Bi8(mu 4-O)2(mu 3-O)2(mu 2-OR)16 (3), Bi6(mu 3-O)4(mu 3-OR)(mu 3-OBi(OR)4)3 (4). Compounds 2 and 3 can also be synthesized via an alcoholysis reaction between BiPh3 and ROH in refluxing dichloromethane or chloroform. Related oxo complexes NaBi4(mu 3-O)2(OR)9(THF)2 (5) and Na2Bi4(mu 3-O)2(OR)10(THF)2 (6) were obtained from BiCl3 and NaOR in THF. The synthesis of 1 and Bi(OC6Cl5)3 via salt elimination was successful when performed in toluene as solvent. For compounds 2-6 the single-crystal X-ray structures were determined. Variable-temperature NMR spectra are reported for 2, 3, and 5. 相似文献
15.
Weber L Bayer P Stammler HG Neumann B 《Chemical communications (Cambridge, England)》2005,(12):1595-1597
Reaction of (eta5-Cp)(CO)2M=P=C(SiMe3)2 4a (M = Mo) and 4b (M = W) with (eta5-Cp*)(CO)2Fe-As=C(NMe2)2 5 affords the eta3-1-arsa-2-phosphaallyl complexes [(eta5-Cp*)(CO)2Fe-AsPC(SiMe3)2]M(CO)2(eta5-Cp) 6a and 6b, the molecular structures of which were determined by X-ray analyses. 相似文献
16.
We have searched for new species of small oxygen-containing gas-phase dianions produced in a secondary ion mass spectrometer by Cs+ ion bombardment of solid samples with simultaneous exposure of their surfaces to O2 gas. The targets were a pure zinc metal foil, a copper-contaminated zinc-based coin, two silicon-germanium samples (Si(1-x)Ge(x)(with x= 6.5% or 27%)) and a piece of titanium metal. The novel dianions Zn3O(4)(2-), Zn4O(5)(2-), CuZn2O(4)(2-), Si2GeO(6)(2-), Ti2O(5)(2-) and Ti3O(7)(2-) have been observed at half-integer m/z values in the negative ion mass spectra. The heptamer dianions Zn3O(4)(2-) and Ti2O(5)(2-) have been unambiguously identified by their isotopic abundances. Their flight times through the mass spectrometer are approximately 20 micros and approximately 17 micros, respectively. The geometrical structures of the two heptamer dianions Ti2O(5)(2-), and Zn3O(4)(2-) are investigated using ab initio methods, and the identified isomers are compared to those of the novel Ge2O(5)(2-) and the known Si2O(5)(2-) and Be3O(4)(2-) dianions. 相似文献
17.
Christe KO Boatz JA Gerken M Haiges R Schneider S Schroer T Tham FS Vij A Vij V Wagner RI Wilson WW 《Inorganic chemistry》2002,41(16):4275-4285
SO(2) solutions of azide anions are bright yellow, and their Raman spectra indicate the presence of covalently bound azide. Removal of the solvent at -64 degrees C from CsN(3) or N(CH(3))(4)N(3) solutions produces yellow (SO(2))(2)N(3)(-) salts. Above -64 degrees C, these salts lose 1 mol of SO(2), resulting in white SO(2)N(3)(-) salts that are marginally stable at room temperature and thermally decompose to the corresponding azides and SO(2). These anions were characterized by vibrational and (14)N NMR spectroscopy and theoretical calculations. Slow loss of the solvent by diffusion through the walls of a sealed Teflon tube containing a sample of CsSO(2)N(3) in SO(2) resulted in white and yellowish single crystals that were identified by X-ray diffraction as CsSO(2)N(3).CsSO(3)N(3) with a = 9.542(2) A, b = 6.2189(14) A, c = 10.342(2) A, and beta = 114.958(4) degrees in the monoclinic space group P2(1)/m, Z = 2, and Cs(2)S(2)O(5).Cs(2)S(2)O(7).SO(2), respectively. Pure CsSO(3)N(3) was also prepared and characterized by vibrational spectroscopy. The S-N bond in SO(2)N(3)(-) is much weaker than that in SO(3)N(3)(-), resulting in decreased thermal stability, an increase in the S-N bond distance by 0.23 A, and an increased tendency to undergo rotational disorder. This marked difference is due to SO(3) being a much stronger Lewis acid (pF(-) value of 7.83) than SO(2) (pF(-) value of 3.99), thus forming a stronger S-N bond with the Lewis base N(3)(-). The geometry of the free gaseous SO(2)N(3)(-) anion was calculated at the RHF, MP2, B3LYP, and CCSD(T) levels. The results show that only the correlated methods correctly reproduce the experimentally observed orientation of the SO(2) group. 相似文献
18.
Angaridis PA Baran P Boca R Cervantes-Lee F Haase W Mezei G Raptis RG Werner R 《Inorganic chemistry》2002,41(8):2219-2228
The nine-membered [-Cu(II)-N-N-](3) ring of trimeric copper-pyrazolato complexes provides a sturdy framework on which water is twice deprotonated in consecutive steps, forming mu(3)-OH and mu(3)-O species. In the presence of excess chlorides the mu(3)-O(H) ligand is replaced by two mu(3)-Cl ions. The interconversion of mu(3)-OH and mu(3)-O and the exchange of mu(3)-O(H) and mu(3)-Cl are reversible, and the three species involved have been structurally characterized: [PPN][Cu(3)(mu(3)-OH)(mu-pz)(3)Cl(3)(thf)].CH(2)Cl(2) (1a), monoclinic P2(1)/n, a = 10.055(2) A, b = 35.428(5) A, c = 15.153(2) A, beta = 93.802(3) degrees, V = 5386(1) A(3), Z = 4; [Bu(4)N][Cu(3)(mu(3)-OH)(mu-pz)(3)Cl(3)] (1b), triclinic P-1, a = 9.135(2) A, b = 13.631(2) A, c = 14.510(2) A, alpha = 67.393(2) degrees, beta = 87.979(2) degrees, gamma = 80.268(3) degrees, V = 1643.2(4) A(3), Z = 2; [PPN](2)[Cu(3)(mu(3)-O)(mu-pz)(3)Cl(3)] (2), monoclinic P2/c, a = 12.807(2) A, b = 13.093(2) A, c = 23.139(4) A, beta = 105.391(3) degrees, V = 3741(1) A(3), Z = 2; [PPN](2)[Cu(3)(mu(3)-Cl)(2)(mu-pz)(3)Cl(3)].0.75H(2)O.0.5CH(2)Cl(2) (3a), triclinic P-1, a = 14.042(2) A, b = 23.978(4) A, c = 25.195(4) A, alpha = 76.796(3) degrees, beta = 79.506(3) degrees, gamma = 77.629(3) degrees, V = 7988(2) A(3), Z = 4; [Bu(4)N](2)[Cu(3)(mu(3)-Cl)(2)(mu-pz)(3)Cl(3)] (3b), monoclinic C2/c, a = 17.220(2) A, b = 15.606(2) A, c = 20.133(2) A, beta = 103.057(2) degrees, V = 5270(1) A(3), Z = 4; [Et(3)NH][Cu(3)(mu(3)-OH)(mu-pz)(3)Cl(3)(pzH)] (4), triclinic P-1, a = 11.498(2) A, b = 11.499(2) A, c = 12.186(2) A, alpha = 66.475(3) degrees, beta = 64.279(3) degrees, gamma = 80.183(3) degrees, V = 1331.0(5) A(3), Z = 2. Magnetic susceptibility measurements show that the three copper centers of 2 are strongly antiferromagnetically coupled with J(Cu-Cu) = -500 cm(-1). 相似文献
19.
The electronic structure and metal-metal bonding in the classic d(7)d(7) tetra-bridged lantern dimer [Pt(2)(O(2)CCH(3))(4)(H(2)O)(2)](2+) has been investigated by performing quasi-relativistic Xalpha-SW molecular orbital calculations on the analogous formate-bridged complex. From the calculations, the highest occupied and lowest unoccupied metal-based levels are delta(Pt(2)) and sigma(Pt(2)), respectively, indicating a metal-metal single bond analogous to the isoelectronic Rh(II) complex. The energetic ordering of the main metal-metal bonding levels is, however, quite different from that found for the Rh(II) complex, and the upper metal-metal bonding and antibonding levels have significantly more ligand character. As found for the related complex [W(2)(O(2)CH)(4)], the inclusion of relativistic effects leads to a further strengthening of the metal-metal sigma bond as a result of the increased involvement of the higher-lying platinum 6s orbital. The low-temperature absorption spectrum of [Pt(2)(O(2)CCH(3))(4)(H(2)O)(2)](2+) is assigned on the basis of Xalpha-SW calculated transition energies and oscillator strengths. Unlike the analogous Rh(II) spectrum, the visible and near-UV absorption spectrum is dominated by charge transfer (CT) transitions. The weak, visible bands at 27 500 and 31 500 cm(-)(1) are assigned to Ow --> sigma(Pt(2)) and OAc --> sigma(Pt(2)) CT transitions, respectively, although the donor orbital in the latter transition has around 25% pi(Pt(2)) character. The intense near-UV band around 37 500 cm(-)(1) displays the typical lower energy shift as the axial substituents are changed from H(2)O to Cl and Br, indicative of significant charge transfer character. From the calculated oscillator strengths, a number of transitions, mostly OAc --> sigma(Pt-O) CT in nature, are predicted to contribute to this band, including the metal-based sigma(Pt(2)) --> sigma(Pt(2)) transition. The close similarity in the absorption spectra of the CH(3)COO(-), SO(4)(2)(-), and HPO(4)(2)(-) bridged Pt(III) complexes suggests that analogous spectral assignments should apply to [Pt(2)(SO(4))(4)(H(2)O)(2)](2)(-) and [Pt(2)(HPO(4))(4)(H(2)O)(2)](2)(-). Consequently, the anomalous MCD spectra reported recently for the intense near-UV band in the SO(4)(2)(-) and HPO(4)(2)(-) bridged Pt(III) complexes can be rationalized on the basis of contributions from either SO(4) --> sigma(Pt-O) or HPO(4) --> sigma(Pt-O) CT transitions. The electronic absorption spectrum of [Rh(2)(O(2)CCH(3))(4)(H(2)O)(2)] has been re-examined on the basis of Xalpha-SW calculated transition energies and oscillator strengths. The intense UV band at approximately 45 000 cm(-)(1) is predicted to arise from several excitations, both metal-centered and CT in origin. The lower energy shoulder at approximately 40 000 cm(-)(1) is largely attributed to the metal-based sigma(Rh(2)) --> sigma(Rh(2)) transition. 相似文献
20.
The reactions between triphenylbismuth, salicylic acid, and the metal alkoxides M(OCH(2)CH(3))(5) (M = Nb, Ta) or Ti[OCH(CH(3))(2)](4) have been investigated under different reaction conditions and in different stoichiometries. Six novel heterobimetallic bismuth alkoxy-carboxylate complexes have been synthesized in good yield as crystalline solids. These include Bi(2)M(2)(sal)(4)(Hsal)(4)(OR)(4) (M = Nb, Ta; R = CH(2)CH(3), CH(CH(3))(2)), Bi(2)Ti(3)(sal)(8)(Hsal)(2), and Bi(2)Ti(4)(O(i)Pr)(sal)(10)(Hsal) (sal = O(2)CC(6)H(4)-2-O; Hsal = O(2)CC(6)H(4)-2-OH). The complexes have been characterized spectroscopically and by single-crystal X-ray diffraction. Compounds of the group V transition metals contain metal ratios appropriate for precursors of ferroelectric materials. The molecules exhibit excellent solubility in common organic solvents and good stability against unwanted hydrolysis. The nature of the thermal decomposition of the complexes has been explored by thermogravimetric analysis and powder X-ray diffraction. We have shown that the complexes are converted to the corresponding oxide by heating in an oxygen atmosphere at 500 degrees C. The mass loss of the complexes, as indicated by thermogravimetric analysis, and the resulting unit cell parameters of the oxides are consistent with the formation of the desired heterobimetallic oxide. The complexes decomposed to form the bismuth-rich phases Bi(4)Ti(3)O(12) and Bi(5)Nb(3)O(15) as well as the expected oxides BiMO(4) (M = Nb, Ta) and Bi(2)Ti(4)O(11). 相似文献