Crystal engineering in ionic liquids. The crystal structures of [Mppyr]3[NdI6] and [Bmpyr]4[NdI6][Tf2N

Single crystals of [mppyr][NdI6] and [bmpyr][NdI6][Tf2N] are the first surprising examples of how the cation of an ionic liquid determines the compound formation from an ionic liquid. Depending upon the variation of the length of the alkyl chain of the quaternary pyrrolidinium cation (C3 and C4, respectively), incorporation of the anion of the ionic liquid, [Tf2N]-, can either be evoked or suppressed.     

Spectroscopic and electrochemical studies of U(IV)-hexachloro complexes in hydrophobic room-temperature ionic liquids [BuMeIm][Tf2N] and [MeBu3N][Tf2N

The behavior of U(IV) octahedral complexes [cation]2[UCl6], where the [cation]+ is [BuMeIm]+ and [MeBu3N]+, is studied using UV/visible spectroscopy, cyclic staircase voltammetry, and rotating disk electrode voltammetry in hydrophobic room-temperature ionic liquids (RTILs) [BuMeIm][Tf2N] and [MeBu3N][Tf2N], where BuMeIm+ and MeBu3N+ are 1-butyl-3-methylimidazolium and tri-n-butylmethylammonium cations, respectively, and Tf2N- is the bis(trifluoromethylsulfonyl)imide anion. The absorption spectra of [cation]2[UCl6] complexes in the RTIL solutions are similar to the diffuse solid-state reflectance spectra of the corresponding solid species, indicating that the octahedral complex UCl6(2-) is the predominant chemical form of U(IV) in Tf2N--based hydrophobic ionic liquids. Hexachloro complexes of U(IV) are stable to hydrolysis in the studied RTILs. Voltammograms of UCl(6)2- at the glassy carbon electrode in both RTILs and at the potential range of -2.5 to +1.0 V versus Ag/Ag(I) reveal the following electrochemical couples: UCl6-/UCl6(2-) (quasi-reversible system), UCl(6)2-/UCl6(3-) (quasi-reversible system), and UCl(6)2-/UCl6(Tf2N)x-3+x (irreversible reduction). The voltammetric half-wave potential, Ep/2, of the U(V)/U(IV) couple in [BuMeIm][Tf2N] is positively shifted by 80 mV compared with that in [MeBu3N][Tf2N]. The positive shift in the Ep/2 value for the quasi-reversible U(IV)/U(III) couple is much greater (250 mV) in [BuMeIm][Tf2N]. Presumably, the potential shift is due to the specific interaction of BuMeIm+ with the uranium-hexachloro complex in ionic liquid. Scanning the negative potential to -3.5 V in [MeBu3N][Tf2N] solutions of UCl6(2-) reveals the presence of an irreversible cathodic process at the peak potential equal to -3.12 V (at 100 mV/s and 60 degrees C), which could be attributed to the reduction of U(III) to U(0).     

A convenient route to lanthanide triiodide THF solvates. Crystal structures of LnI(3)(THF)(4) [Ln = Pr] and LnI(3)(THF)(3.5) [Ln = Nd, Gd, Y

The reaction between 1.5 equiv of elemental iodine and rare earth metals in powder form in THF at room temperature gives the rare earth triiodides LnI(3)(THF)(n)() in good yields. Purification by Soxhlet extraction of the crude solids with THF reliably gives the THF adducts LnI(3)(THF)(4) [Ln = La, Pr] and LnI(3)(THF)(3.5) [Ln = Nd, Sm, Gd, Dy, Er, Tm, Y] as microcrystalline solids. X-ray crystallography reveals that the early, larger lanthanide iodide PrI(3)(THF)(4) crystallizes as discrete molecules having a pentagonal bipyramidal structure, whereas the later, smaller lanthanide iodides LnI(3)(THF)(3.5) [Ln = Nd, Gd, Y] crystallize as solvent-separated ion pairs [LnI(2)(THF)(5)][LnI(4)(THF)(2)] in which the cations adopt a pentagonal bipyramidal geometry and the anions adopt an octahedral geometry in the solid state.     

Uranyl complexation by chloride ions. Formation of a tetrachlorouranium(VI) complex in room temperature ionic liquids [Bmim][Tf2N] and [MeBu3N][Tf2N

The tetrachlorouranium(VI) complex is formed in [Bmim][Tf2N] and [MeBu3N][Tf2N] from a uranium(VI) solution in the presence of a stoichiometric quantity of chloride ions. The [UVIO2Cl4]2- absorption and emission spectra show bands splitting in comparison with the [UVIO2]2+ spectra, as observed in the solid state, organic solvents, and chloroaluminate-based ionic liquids. The fluorescence lifetime of [UO2Cl4]2- in [MeBu3N][Tf2N] is 0.7 +/- 0.1 mus. The reduction potential of this complex is -1.44 and -1.8 V vs Ag/Ag+ respectively in [Bmim][Tf2N] and [MeBu3N][Tf2N] and does not depend on the chloride concentration. The mechanism proposed for the redox process is a monoelectronic reduction to form [UVO2Cl4]3-, followed by a chemical reaction. The tetrachlorouranium(V) complex seems more stable in [Bmim][Tf2N] than in [MeBu3N][Tf2N]. The electrochemical analysis put in evidence specific interactions of the ionic liquid cation with the uranium anionic species.     

{[P(o-tolyl)3]Br}2[Cu2Br6](Br2)--an ionic compound containing molecular bromine

Dark green cuboid-shaped crystals of the composition {[P(o-tolyl) 3]Br} 2[Cu 2Br 6](Br 2) are obtained by the reaction of P(o-tolyl) 3 and CuBr 2 with Br 2 in the ionic liquid [NMeBu 3][N(Tf) 2]. The bromocuprate crystallizes triclinic [space group P1; Z = 1; a = 10.667(2) A; b = 10.695(2) A; c = 11.582(2) A; alpha = 74.42(3) degrees ; beta = 75.64(3) degrees ; and gamma = 85.68(3) degrees ]. The title compound is constituted of {[P(o-tolyl) 3]Br} (+) cations and [Cu 2Br 6] (2-) anions and contains molecular dibromine [d Br-Br = 2.341(1) A]. The latter is verified by thermogravimetry and mass spectrometry.     

Synthesis and study of hexanuclear molybdenum clusters containing thiolate ligands

Four hexanuclear molybdenum chloride cluster complexes containing terminal thiolate ligands have been synthesized and fully characterized. (Bu 4N) 2[Mo 6Cl 8(SEt) 6] was prepared by reacting Na 2[Mo 6Cl 8(OMe) 6] with an excess of ethanethiol in refluxing tetrahydrofuran. (PPN) 2[Mo 6Cl 8(SBu) 6], (Bu 4N) 2[Mo 6Cl 8(SBn) 6], and (Bu 4N) 2[Mo 6Cl 8(SNC 8H 6) 6] (C 8H 6NS (-) = 3-indolylthiolate) were subsequently prepared in the reaction of [Mo 6Cl 8(SEt) 6] (2-) with an excess of HSR (R = Bu, Bn or 3-indolyl). Single crystal X-ray diffraction analyses were performed on two of these complexes: (PPN) 2[Mo 6Cl 8(SEt) 6].Et 2O, crystallizes in the triclinic space group P1 with a = 12.3894(11), b = 13.7651(12), c = 15.0974(13), alpha = 103.975(2), beta = 99.690(2), gamma = 98.062(2), and Z = 1; (PPh 3Me) 2[Mo 6Cl 8(SBn) 6].2NO 2CH 3, also crystallizes in the P1 space group with a = 12.1574(16), b = 13.4441(17), c = 14.2132(18), alpha = 89.654(2), beta = 88.365(2), gamma = 71.179(2), and Z = 1. Our studies demonstrate that [Mo 6Cl 8(SEt) 6] (2-) displays luminescent properties and that the same complex undergoes substitution reactions with different thiols, as well as reaction with electrophilic reagents such as MeI.     

Mononitrosyl tris(thiolate) iron complex [Fe(NO)(SPh)3]- and dinitrosyl iron complex [(EtS)2Fe(NO)2]-: formation pathway of dinitrosyl iron complexes (DNICs) from nitrosylation of biomimetic rubredoxin [Fe(SR)4]2-/1- (R = Ph, Et)

Nitrosylation of the biomimetic reduced- and oxidized-form rubredoxin [Fe(SR)4]2-/1- (R = Ph, Et) in a 1:1 stoichiometry led to the formation of the extremely air- and light-sensitive mononitrosyl tris(thiolate) iron complexes (MNICs) [Fe(NO)(SR)3]- along with byproducts [SR]- or (RS)2. Transformation of [Fe(NO)(SR)3]- into dinitrosyl iron complexes (DNICs) [(RS)2Fe(NO)2]- and Roussin's red ester [Fe2(mu-SR)2(NO)4] occurs rapidly under addition of 1 equiv of NO(g) and [NO]+, respectively. Obviously, the mononitrosyl tris(thiolate) complex [Fe(NO)(SR)3]- acts as an intermediate when the biomimetic oxidized- and reduced-form rubredoxin [Fe(SR)4]2-/1- exposed to NO(g) were modified to form dinitrosyl iron complexes [(RS)2Fe(NO)2]-. Presumably, NO binding to the electron-deficient [Fe(III)(SR)4]- and [Fe(III)(NO)(SR)3]- complexes triggers reductive elimination of dialkyl/diphenyl disulfide, while binding of NO radical to the reduced-form [Fe(II)(SR)4]2- induces the thiolate-ligand elimination. Protonation of [Fe(NO)(SEt)3]- yielding [Fe(NO)(SPh)3]- by adding 3 equiv of thiophenol and transformation of [Fe(NO)(SPh)3]- to [Fe(NO)(SEt)3]- in the presence of 3 equiv of [SEt]-, respectively, demonstrated that complexes [Fe(NO)(SPh)3]- and [Fe(NO)(SEt)3]- are chemically interconvertible. Mononitrosyl tris(thiolate) iron complex [Fe(NO)(SPh)3]- and dinitrosyl iron complex [(EtS)2Fe(NO)2]- were isolated and characterized by X-ray diffraction. The mean NO bond distances of 1.181(7) A (or 1.191(7) A) in complex [(EtS)2Fe(NO)2]- are nearly at the upper end of the 1.178(3)-1.160(6) A for the anionic {Fe(NO)2}9 DNICs, while the mean FeN(O) distances of 1.674(6) A (or 1.679(6) A) exactly fall in the range of 1.695(3)-1.661(4) A for the anionic {Fe(NO)2}9 DNICs.     

Influence of gamma irradiation on hydrophobic room-temperature ionic liquids [BuMeIm]PF6 and [BuMeIm](CF3SO2)2N

Stability of neat hydrophobic Room-Temperature Ionic Liquids (RTIL) [BuMeIm]X, where [BuMeIm]+ is 1-butyl-3-methylimidazolium and X- is PF6-, and (CF3SO2)2N-, was studied under gamma radiolysis (137Cs) in an argon atmosphere and in air. It was found that the density, surface tension, and refraction index of RTILs are unchanged even by an absorbed dose of approximately 600 kGy. Studied RTILs exhibit considerable darkening when subjected to gamma irradiation. The light absorbance of ionic liquids increases linearly with the irradiation dose. Water has no influence on radiolytic darkening. A comparative study of [BuMeIm]X and [Bu4N][Tf2N] leads to the conclusion that the formation of colored products is related to gamma radiolysis of the [BuMeIm]+ cation. The radiolytic darkening kinetics of RTILs is influenced by the anions as follows: Cl- < (CF3SO2)2N- < PF6-. Electrospray ionization mass spectrometry and NMR analysis reveal the presence of nonvolatile radiolysis products at concentrations below 1 mol% for an absorbed dose exceeding 1200 kGy. Initial step of BuMeIm+ cation radiolysis is the loss of the Bu* group, the H* atom from the 2 position on the imidazolium ring, and the H* atom from the butyl chain. Radiolysis of ionic liquid anions yields F* and CF3* from PF6- and [Tf2N]-, respectively. Recombinations of these primary products of radiolysis lead to various polymeric and acidic species.     

N-(trifluoromethylsulfonyl)aryloxytrifluoromethylsulfoximines [ArO-SO(CF3)=NTf] and N-aryltriflimides Ar-N(Tf)2 by thermal and photolytic dediazoniation of [ArN2][BF4] in [BMIM][Tf2N] ionic liquid: exploiting the ambident nucleophilic character of a "nonnucleophilic" anion

Arenediazonium tetrafluoroborate salts undergo metathesis on immobilization in 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonato)amide [BMIM][Tf(2)N]. The "noncoordinating", "nonnucleophilic" [Tf(2)N] anion acts as an ambident nucleophile toward the aryl cations, formed via thermal dediazoniation, to give predominantly the oxy anion quenching products [ArO-SO(CF(3))=NTf], with minimal formation of ArN(Tf)(2), irrespective of the nature of the substituent(s) on the ArN(2)+. Strong preference for the formation of oxygen trapping products did not change under photolytic conditions, where dediazoniation occurs at room temperature. A minimal amount of the Schiemann product ArF is also formed in both thermal and photolytic dediazoniation, depending on the substituent(s). Progress of dediazoniation in the IL (both thermal and photolytic) and the evolution of the products were directly monitored by (1)H and (19)F NMR. According to DFT (Density Functional Theory) calculations, PhN(Tf)(2) is more stable than PhO-SO(CF(3))=NTf by 15-17 kcal/mol, depending on the basis set. Inclusion of solvation effects (PCM, with acetone and with CH(2)ClCH(2)Cl as solvent) did not change this preference. The [ArN(2)][BF(4)] dediazoniation in [BMIM][Tf(2)N] resulted in synthesis and characterization of a series of hitherto unknown [ArO-SO(CF(3))=NTf] compounds. The X-ray structure of MesO-SO(CF(3))=NTf (Mes = mesityl) is reported. On the basis of extraction studies, suitable solvent systems have been identified that remove the products without dissolving [BMIM][NTf(2)], thus overcoming product recovery difficulties typically associated with the use of this IL.     

Trimerization of alkali dicyanamides M[N(CN)2] and formation of tricyanomelaminates M3[C6N9] (M = K, Rb) in the melt: crystal structure determination of three polymorphs of K[N(CN)2], two of Rb[N(CN)2], and one of K3[C6N9] and Rb3[C6N9] from X-ray powder diffractometry

The alkali dicyanamides M[N(CN)2] (M=K, Rb) were synthesized through ion exchange, and the corresponding tricyanomelaminates M3[C6N9] were obtained by heating the respective dicyanamides. The thermal behavior of the dicyanamides and their reaction to form the tricyanomelaminates were investigated by temperature-dependent X-ray powder diffractometry and thermoanalytical measurements. Potassium dicyanamide K[N(CN)2] was found to undergo four phase transitions: At 136 degrees C the low-temperature modification alpha-K[N(CN)2] transforms to beta-K[N(CN)2], and at 187degrees C the latter transforms to the high-temperature modification gamma-K[N(CN)2], which melts at 232 degrees C. Above 310 degrees C the dicyanamide ions [N(CN)2]- trimerize and the resulting tricyanomelaminate K3[C6N9] solidifies. Two modifications of rubidium dicyanamide have been identified: Even at -25 degrees C, the a form slowly transforms to beta-Rb[N(CN)2] within weeks. Rb[N(CN)2] has a melting point of 190 degrees C. Above 260 degrees C the dicyanamide ions [N(CN)2]- of the rubidium salt trimerize in the melt and the tricyanomelaminate Rb3[C6N9] solidifies. The crystal structures of all phases were determined by powder diffraction methods and were refined by the Rietveld method. alpha-K[N(CN)2] (Pbcm, a = 836.52(1), b = 46.90(1), c =7 21.27(1) pm, Z = 4), gamma-K[N(CN)2] (Pnma, a = 855.40(3), b = 387.80(1), 1252.73(4) pm, Z = 4), and Rb[N(CN)2] (C2/c, a = 1381.56(2), b = 1000.02(1), c = 1443.28(2) pm, 116.8963(6) degrees, Z = 16) represent new structure types. The crystal structure of beta-K[N(CN)2] (P2(1/n), a = -726.92(1), b 1596.34(2), c = 387.037(5) pm, 111.8782(6) degrees, Z = 4) is similar but not isotypic to the structure of alpha Na[N(CN)2]. alpha-Rb[N(CN)2] (Pbcm, a = 856.09(1), b = 661.711(7), c = 765.067(9) pm, Z = 4) is isotypic with alpha-K[N(CN)2]. The alkali dicyanamides contain the bent planar anion [N(CN)2]- of approximate symmetry C2, (average bond lengths: C-N(bridge) 133, C-N(term) 113 pm; average angles N-C-N 170 degrees, C-N-C 120 degrees). K3[C6N9] (P2(1/c), a = 373.82(1), b = 1192.48(5), c = 2500.4(1) pm, beta = 101.406(3) degrees, Z = 4) and Rb,[C6N9] (P2(1/c), a = 389.93(2), b = 1226.06(6), c = 2547.5(1) pm, 98.741(5) degrees, Z=4) are isotypic and they contain the planar cyclic anion [C6N9]3-. Although structurally related, Na3[C6N9] is not isotypic with the tricyanomelaminates M3[C6N9] (M = K, Rb).     

Ionic‐Liquid‐Based Synthesis of the Bromine‐Rich Bromidoplatinates [NBu3Me]2[Pt2Br10](Br2)2 and [NBu3Me]2[Pt2Br10](Br2)3

The bromine‐rich bromidoplatinates(IV) [NBu₃Me]₂[Pt₂Br₁₀](Br₂)₂ ( 1 ) and [NBu₃Me]₂[Pt₂Br₁₀](Br₂)₃ ( 2 ) were prepared by reaction of PtBr₄ and elemental bromine in the ionic liquid [MeBu₃N][N(Tf)₂] [N(Tf)₂ = bis(trifluoromethylsulfonyl)amide]. Both bromine‐rich bromidoplatinates(IV) contain [Pt₂Br₁₀]^2– anions and [NBu₃Me]⁺ cations as voluminous building units with an almost identical structural arrangement and very similar unit cells. The difference of the title compounds is related to the specific number of Br₂ molecules that link the [Pt₂Br₁₀]^2– anions to three‐dimensional networks. Whereas 1 is relatively stable under inert conditions, 2 releases bromine even at ambient pressure. The title compounds are characterized by single‐crystal structure analysis and Raman spectroscopy.     

Li24[MnN3]3N2 and Li5[(Li1-xMnx)N]3, two intermediates in the decomposition path of Li7[MnN4] to Li2[(Li1-xMnx)N]: an experimental and theoretical study

The crystal structure of Li7[Mn(V)N4] was re-determined. Isolated tetrahedral [Mn(V)N4](7-) ions are arranged with lithium cations to form a superstructure of the CaF2 anti-type (P4bar3n, No. 218, a = 956.0(1) pm, Z = 8). According to measurements of the magnetic susceptibility, the manganese (tetrahedral coordination) is in a d(2) S = 1 state. Thermal treatment of Li7[Mn(V)N4] under argon in the presence of elemental lithium at various temperatures leads to Li24[Mn(III)N3]3N2, Li5[(Li1-xMnx)N]3, and Li2[(Li1-xMn(I)x)N], respectively. Li24[Mn(III)N3]3N2 (P3bar1c, No. 163, a = 582.58(6) pm, c = 1784.1(3) pm, Z = 4/3) crystallizes in a trigonal unit cell, containing slightly, but significantly nonplanar trigonal [MnN3](6-) units with C3v symmetry. Measurements of the magnetic susceptibility reveal a d(4) S = 1 spin-state for the manganese (trigonal coordination). Nonrelativistic spin-polarized DFT calculations with different molecular models lead to the conclusion that restrictions in the Li-N substructure are responsible for the distortion from planarity of the [Mn(III)N3](6-). Li5[(Li1-xMnx)N]3 (x = 0.59(1), P6bar2m, No. 189, a = 635.9(3) pm, c = 381.7(2) pm, Z = 1) is an isotype of Li5[(Li1-xNix)N]3 with manganese in an average oxidation state of about +1.6. The crystal structure is a defect variant of the alpha-Li3N structure type with the transition metal in linear coordination by nitrogen. Li2[(Li1-xMn(I)x)N] (x = 0.67(1), P6/mmm, No. 191, a = 371.25(4) pm, c = 382.12(6) pm, Z = 1) crystallizes in the alpha-Li3N = Li2[LiN] structure with partial substitution of the linearly nitrogen-coordinated Li-species by manganese(I). Measurements of the magnetic susceptibility are consistent with manganese (linear coordination) in a low-spin d(6) S = 1 state.     

Homoleptic alkaline earth metal bis(trifluoromethanesulfonyl)imide complex compounds obtained from an ionic liquid

The first homoleptic alkaline earth bis(trifluoromethanesulfonyl)imide (Tf2N) complexes [mppyr]2[Ca(Tf2N)4], [mppyr]2[Sr(Tf2N)4], and [mppyr][Ba(Tf2N)3] were crystallized from a solution of the respective alkaline earth bis(trifluoromethanesulfonyl)imide and the ionic liquid [mppyr][Tf2N] (mppyr = 1,1-N-methyl-N-propylpyrrolidinium). In the calcium and strontium compounds, the alkaline earth metal (AE) is coordinated by four bidentately chelating Tf2N ligands to form isolated (distorted) square antiprismatic [AE(Tf2N)4]2- complexes which are separated by N-methyl-N-propylpyrrolidinium cations. In contrast, the barium compound, [mppyr][Ba(Tf2N)3], forms an extended structure. Here the alkaline earth cation is surrounded by six oxygen atoms belonging to three Tf2N- anions which coordinate in a bidentate chelating fashion. Three further oxygen atoms of the same ligands are linking the Ba2+ cations to infinite (infinity)(1)[Ba(Tf2N)3] chains.     

STRUCTURE STUDIES OF [Et_4N]_4[Cu_8(i-mnt)_6] (i-mnt=S_2C=C(CN)_2) AND [Me_4N]_4[Cu_5Ag_3(i-mnt)_6]·H_2O

<正> [Me4N]6[Ag6(i-mnt)6].H2O(1),[Et4N]4[Cu8(i-mnt)6](2) and [Me4N]4-[Cu5Ag3(i-mnt)6].H2O(3)(i-mnt=S2C=C(CN)2) were synthesized. The crystal and molecular structure of the complex 1 was reported by us.The structure of the complex 2 was determined from single crystal X-ray diffraction data. [Et4N]4[Cu8(i-mnt)s] 2, Mr=1870.46, monoclinic, P21/n, a=14.724(6), b = 17.228(3), c=15.59(1)A,β= 100.75(7)°,V=3886.3A3;Z = 2,Dc= 1.598 g/cm3. Complex 3 has been characterized by ICP elemental analyses and IR spectrum.     

Liquid/solid interface of ultrathin ionic liquid films: [C1C1Im][Tf2N] and [C8C1Im][Tf2N] on Au(111)

Ultrathin films of two imidazolium-based ionic liquids (IL), [C(1)C(1)Im][Tf(2)N] (= 1,3-dimethylimidazolium bis(trifluoromethyl)imide) and [C(8)C(1)Im][Tf(2)N] (= 1-methyl-3-octylimidazolium bis(trifluoromethyl)imide) were prepared on a Au(111) single-crystal surface by physical vapor deposition in ultrahigh vacuum. The adsorption behavior, orientation, and growth were monitored via angle-resolved X-ray photoelectron spectroscopy (ARXPS). Coverage-dependent chemical shifts of the IL-derived core levels indicate that for both ILs the first layer is formed from anions and cations directly in contact with the Au surface in a checkerboard arrangement and that for [C(8)C(1)Im][Tf(2)N] a reorientation of the alkyl chain with increasing coverage is found. For both ILs, geometry models of the first adsorption layer are proposed. For higher coverages, both ILs grow in a layer-by-layer fashion up to thicknesses of at least 9 nm (>10 ML). Moreover, beam damage effects are discussed, which are mainly related to the decomposition of [Tf(2)N](-) anions directly adsorbed at the gold surface.     

Direct measurement of the hydrogen-bonding effect on the intrinsic redox potentials of [4Fe-4S] cubane complexes

To probe how H-bonding effects the redox potential changes in Fe-S proteins, we produced and studied a series of gaseous cubane-type analogue complexes, [Fe(4)S(4)(SEt)(3)(SC(n)H(2n+1))](2-) and [Fe(4)S(4)(SEt)(3)(SC(n)H(2n)OH)](2-) (n = 4, 6, 11; Et = C(2)H(5)). Intrinsic redox potentials for the [Fe(4)S(4)](2+/3+) redox couple involved in these complexes were measured by photoelectron spectroscopy. The oxidation energies from [Fe(4)S(4)(SEt)(3)(SC(n)H(2n)OH)](2-) to [Fe(4)S(4)(SEt)(3)(SC(n)H(2n)OH)](-) were determined directly from the photoelectron spectra to be approximately 130 meV higher than those for the corresponding [Fe(4)S(4)(SEt)(3)(SC(n)H(2n+1))](2-) systems, because of the OH...S hydrogen bond in the former. Preliminary Monte Carlo and density functional calculations showed that the H-bonding takes place between the -OH group and the S on the terminal ligand in [Fe(4)S(4)(SEt)(3)(SC(6)H(12)OH)](2-). The current data provide a direct experimental measure of a net H-bonding effect on the redox potential of [Fe(4)S(4)] clusters without the perturbation of other environmental effects.     

Benzo[2,1-c:3,4-c']bis(1,2,3-thiaselenazole) (BSe) and its charge trasfer chemistry. Crystal and electronic structure of [BSe]3[ClO4]2

The S-Se-N-based heterocycle benzo[2,1-c:3,4-c']bis(1,2,3-thiaselenazole) (BSe) can be prepared by the condensation of 1,4-diaminobenzene-2,3-dithiol with selenium tetrachloride. Crystals of this compound are not isomorphous with the related benzo[2,1-c:3,4-c']bis(1,2,3-dithiazole) (BT); a structure is adopted that allows for more extensive intermolecular Se- - -Se contacts. Electro-oxidation of BSe in the presence of [n-Bu4N][ClO4] affords metallic green needles of the charge transfer salt [BSe]3[ClO4]2, which exhibit a pressed pellet conductivity sigma(RT) = 10(-1) S cm(-1). The crystal structure of [BSe]3[ClO4]2 consists of slipped pi-stacks based on the triple-decker closed shell [BSe]3(2+) building block. The packing is analogous to that found for the charge transfer salt [BT]3[FSO3]2, for which sigma(RT) = 10(-2) S cm(-1). Extended Hückel band structure calculations on these two (sulfur- and selenium-based) 3:2 salts reveal more extensive intermolecular interactions in the selenium compound. As a result, the latter has a more two-dimensional electronic structure. Crystal data for Se2S2N2C6H2, a = 4.103(2) A, b = 12.159(2) A, c = 16.171(2) A, orthorhombic, Pbnm, Z = 4. Crystal data for Se6S6N6C18H6Cl2O4, a =17.00(1) A, b = 18.36(1) A, c = 10.679(4) A, 110.27(3), monoclinic, C2/c, Z = 4.     

Preparation and characterization of ultrathin [Ru(CO)3Cl2]2 and [BMIM][Tf2N] films on Al2O3/NiAl(110) under UHV conditions

Towards a better understanding of the interface chemistry of ionic liquid (IL) thin film catalytic systems we have applied a rigorous surface science model approach. For the first time, a model homogeneous catalyst has been prepared under ultrahigh vacuum conditions. The catalyst, di-μ-chlorobis(chlorotricarbonylruthenium) [Ru(CO)(3)Cl(2)](2), and the solvent, the IL 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [BMIM][Tf(2)N], have been deposited by physical vapor deposition onto an alumina model support [Al(2)O(3)/NiAl(110)]. First, the interaction between thin films of [Ru(CO)(3)Cl(2)](2) and the support is investigated. Then, the ruthenium complex is co-deposited with the IL and the influence of the solvent on the catalyst is discussed. D(2)O, which is a model reactant, is further added. Growth, surface interactions, and mutual interactions in the thin films are studied with IRAS in combination with density functional (DFT) calculations. At 105 K, molecular adsorption of [Ru(CO)(3)Cl(2)](2) is observed on Al(2)O(3)/NiAl(110). The IRAS spectra of the binary [Ru(CO)(3)Cl(2)](2) + [BMIM][Tf(2)N] and ternary [Ru(CO)(3)Cl(2)](2) + [BMIM][Tf(2)N] + D(2)O show every characteristic band of the individual components. Above 223 K, partial decomposition of the ruthenium complex leads to species of molecular nature attributed to Ru(CO) and Ru(CO)(2) surface species. Formation of metallic ruthenium clusters occurs above 300 K and the model catalyst decomposes further at higher temperatures. Neither the presence of the IL nor of D(2)O prevents this partial decomposition of [Ru(CO)(3)Cl(2)](2) on alumina.     

铁铂硫原子簇化合物的合成与结构研究 V: [MoFe3S4]类立方烷簇合物的转化反应和[Et4N]3[Mo2Fe6S8(SC6H4CH3-m)3Cl6]的晶体结构

具[MoFe2S4]类立方烷结构单元的双类立方烷化合物[Et4N]4[Mo2Fe7S8(SR)12](1a,R=Ph; 1b, R=tolyl-m)或单类立方烷化合物[MoFe3S4(dteR2)5](2a, R=Me; 2b, R=Et)与酰氯在乙腈中反应, 分别得到不含Fe桥的双类立方烷化合物(Et4N)3[Mo2Fe6S8(SR)3Cl6](3a, R=Ph; 3b, R=toly-m)与[MoFe3S4]骨架支解后的Fe(dteR2)2Cl(4a, R=Me; 4b, R=Et)。说明在相同反应条件下, [MoFe3S4]单元在1中比在2中稳定, 本文首次将1型与3型结构通过一步化学反应连系起来。3型化合物的产生得到X射线衍射测定及^1H NMR谱的证实。本文报道3b的单晶结构及3的^!H NMR数据, 3b属六方晶系, P63/m, a=1.6827(3), c=1.5951(16)nm; V=3.91158nm^3; Dc=1.491g/cm^3;Z=2; F(000)=1780; 偏离因子R=0.048, 化合物2与酰氯反应产生4, 由红外及紫外可见光谱证实。     

Solvation of UCl6(2-) anionic complex by MeBu3N(+), BuMe2Im(+), and BuMeIm(+) cations

The complexes [MeBu 3N] 2[UCl 6] and [BuMe 2Im] 2[UCl 6] were characterized in the solid state and in solution of [MeBu 3N][Tf 2N], [BuMe 2Im][Tf 2N], and [BuMeIm][Tf 2N] room-temperature ionic liquids using single-crystal XRD, EXAFS, electrochemistry, UV-visible absorption spectroscopy, and NMR. In the solid state and in solution, the existence of hydrogen bonding between the UCl 6 (2-) complex and the ionic liquid cations was revealed by these techniques. The MeBu 3N (+) cation interacts with UCl 6 (2-) via the protons on the alpha-carbon atoms of nitrogen. The protons of the imidazolium ring account for the interaction between the BuMe 2Im (+) cation and the UCl 6 (2-) anion. For the BuMeIm (+) cation the major interaction was confirmed between the most acidic proton on C(2) and the chlorides of UCl 6 (2-). The experimental results also show that the intensity of the interaction between the UCl 6 (2-) anion and the cation varies with the ionic liquid cation in the following order: MeBu 3N (+) approximately BuMe 2Im (+) < BuMeIm (+).