共查询到20条相似文献,搜索用时 15 毫秒
1.
Xu L Setyawati IA Pierreroy J Pink M Young VG Patrick BO Rettig SJ Orvig C 《Inorganic chemistry》2000,39(26):5958-5963
The oxorhenium(V) complexes with ligands containing N4 (H2pmen) and N4O2 (H2bbpen, H2Clbbpen, and H2bped) donor atom sets have been synthesized. X-ray crystallographic analyses of the [ReO(H2pmen)Cl2]+, [ReO(bbpen)]+, and [ReO(bped)]+ complexes showed that all three cations share a rare seven-coordinate structure with a distorted pentagonal bipyramidal geometry, which represents a novel and potentially general structural motif in ReV = O complexes. 1H NMR spectroscopy shows that the structures of the complexes are retained in the solution. 相似文献
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用CNDO/2(s,p,d)方法研究了类立方烷系列Fe-S簇合物[Fe_4S_4Cl_4(?)(S_2CNEt_2)_n]~(2-)(n=0,1,2,4)的电子结构。得出[S_2CN(Et)_2]-螯合配位Fe_4S_4~(2+)簇合物中存在两类不同价态铁原子的结论;骨架Fe_4S_4~(2+)中μ_3-S电子是非定域化的,同Mssbauer谱测定结果一致。讨论了簇合物Fe—Fe之间的成键作用、螫合配体的作用和氧化还原性质。 相似文献
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The treatment of Cr(III)(X(4)SQ)(3) (SQ = o-semiquinonate; X = Cl and Br) with acetonitrile affords trans-Cr(III)(X(4)SQ)(X(4)Cat)(CH(3)CN)(2) (X = Cl (1) and Br (2)). In the presence of 2,2'-bipyridine (bpy) or 3,4,7,8-tetramethyl-1,10-phenanthrene (tmphen), the reaction affords Cr(III)(X(4)SQ)(X(4)Cat)(bpy).nCH(3)CN (X = Cl, n = 1 (3); X = Br, n = 0.5 (4)) or Cr(III)(X(4)SQ)(X(4)Cat)(tmphen) (X = Cl (5) and Br (6)), respectively. All of the complexes show a ligand-based mixed-valence (LBMV) state with SQ and Cat ligands. The LBMV state was confirmed by the presence of the interligand intervalence charge-transfer band. Spectroscopic studies in several solvent media demonstrate that the ligand dissociation included in the conversion of Cr(III)(X(4)SQ)(3) to 1-6 occurs only in solvents with relatively high polarity. On the basis of these results, the effects of solvent media were examined and an equilibrium, Cr(III)(X(4)SQ)(3) <--> Cr(III)(X(4)BQ)(X(4)SQ)(X(4)Cat) (BQ = o-benzoquinone), is proposed by assuming an interligand electron transfer induced by solvent polarity. 相似文献
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Christine Bauhofer Hansjürgen Mattausch Reinhard K. Kremer Arndt Simon 《无机化学与普通化学杂志》1995,621(9):1501-1507
The Gadolinium Carbide Halides, Gd4C2X3 (X = Cl, Br) The compounds Gd4C2X3 (X = Cl, Br) and Tb4C2Br3 have been prepared by reaction of the metals (RE), REX3, and C in sealed Ta capsules at 1 100° and 1 300°C, respectively. Monophasic samples of Gd4C2Br3 and Tb4C2Br3 were obtained by reacting stoichiometric mixtures of the starting materials for five days. The needle shaped crystals are bronze-coloured and sensitive to air and moisture. Gd4C2X3 crystallizes in the space group Pnma (No. 62) with lattice constants a = 1 059.6(4), b = 368.4(1), c = 1 962.7(8) pm (Gd4C2Cl3), a = 1 084.4(1), b = 373.0(1), c = 2 036.1(1) pm (Gd4C2Br3). According to Guinier photographs, Tb4C2Br3 is isotypic (a = 1 074.3(2), b = 370.6(1), c = 2 019.4(1) pm). In the crystal structure C is octahedrally coordinated by Gd. The Gd6 octahedra are linked via common edges to form corrugated layers. The X-anions coordinate all free edges and corners of these layers and connect them via Xi? Xi contacts parallel [001]. Gd4C2Br3 shows metallic conductivity. The magnetic susceptibility follows at high temperatures a Curie Weiss law with an effective moment of 7.95 μB. At temperatures below 50 K antiferromagnetic order is observed. 相似文献
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The reactions of Te2Br with MoOBr3, TeCl4 with MoNCl2/MoOCl3, and Te with WBr5/WOBr3 yield black, needle-like crystals of [Te15X4][MOX4]2 (M = Mo, W; X = Cl, Br). The crystal structure determinations [Te15Br4][MoOBr4]2: monoclinic, Z = 1, C2/m, a = 1595.9(4) pm, b = 403.6(1) pm, c = 1600.4(4) pm, β = 112.02(2)°; [Te15Cl4][MoOCl4]2: C2/m, a = 1535.3(5) pm, b = 402.8(2) pm, c = 1569.6(5) pm, β = 112.02(2)°; [Te15Br4][WOBr4]2: C2, a = 1592.4(4) pm, b = 397.5(1) pm, c = 1593.4(5) pm, β = 111.76(2)° show that all three compounds are isotypic and consist of one-dimensional ([Te15X4]2+)n and ([MOX4]?)n strands. The structures of the cationic strands are closely related to the tellurium subhalides Te2X (X = Br, I). One of the two rows of halogen atoms that bridges the band of condensed Te6 rings is stripped off, and additionally one Te position has only 75% occupancy which leads to the formula ([Te15X4]2+)n (X = Cl, Br) for the cation. The anionic substructures consist of tetrahalogenooxometalate ions [MOX4]? that are linked by linear oxygen bridges to polymeric strands. The compounds are paramagnetic with one unpaired electron per metal atom indicating oxidation state Mv, and are weak semiconductors. 相似文献
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《Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy》1992,48(2):205-211
Vibrational spectra are reported and assigned for the planar D3h symmetry cyclopropenium cations [C3X3]+ (X= Cl, Br or I) from investigations of the compounds C3Cl3AlCl4, C3Cl3GaCl4, C3Cl3FeCl4, C3Cl3SbCl6, C3Br3AlBr4 and C3l4, using conventional infrared and Raman spectroscopy and Fourier transform Raman spectroscopy. The symmetric C—X stretching modes of [C3X3]+ occur at 458, 269 and 180 cm−1 and the ring-breathing modes at 1790, 1732 and ca. 1650 cm−1 in [C3Cl3]+, [C3Br3]+ and [C3I3]+, respectively. A normal coordinate calculation is performed for [C3Cl3]+. 相似文献
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A series of mercury(II) ionic liquids, [C(n)mim][HgX(3)], where [C(n)mim] = n-alkyl-3-methylimidazolium with n = 3, 4 and X = Cl, Br, have been synthesized following two different synthetic approaches, and structurally characterized by means of single-crystal X-ray structure analysis ([C(3)mim][HgCl(3)] (1), Cc (No. 9), Z = 4, a = 16.831(4) ?, b = 10.7496(15) ?, c = 7.4661(14) ?, β = 105.97(2)°, V = 1298.7(4) ?(3) at 298 K; [C(4)mim][HgCl(3)] (2), Cc (No. 9), Z = 4, a = 17.3178(28) ?, b = 10.7410(15) ?, c = 7.4706(14) ?, β = 105.590(13)°, V = 1338.5(4) ?(3) at 170 K; [C(3)mim][HgBr(3)] (3), P2(1)/c (No. 14), Z = 4, a = 10.2041(10) ?, b = 10.7332(13) ?, c = 14.5796(16) ?, β = 122.47(2)°, V = 1347.2(3) ?(3) at 170 K; [C(4)mim][HgBr(3)] (4), Cc (No. 9), Z = 4, a = 17.093(3) ?, b = 11.0498(14) ?, c = 7.8656(12) ?, β = 106.953(13)°, V = 1421.1(4) ?(3) at 170 K). Compounds 1, 2, and 4 are isostructural and are characterized by strongly elongated trigonal [HgX(5)] bipyramids, which are connected via common edges in chains. In contrast, 3 contains [Hg(2)Br(6)] units formed by two edge-sharing tetrahedra. With melting points of 69.3 °C (1), 93.9 °C (2), 39.5 °C (3), and 58.3 °C (4), all compounds qualify as ionic liquids. 1, 2, and 4 solidify upon fast cooling as glasses, whereas 3 crystallizes. Cyclic voltammetry shows two separate, quasi-reversible redox processes, which can be associated with the 2Hg(2+)/Hg(2)(2+) and Hg(2)(2+)/2Hg redox couples. 相似文献
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Roszak S Koski WS Kaufman JJ Balasubramanian K 《SAR and QSAR in environmental research》2001,11(5-6):383-396
Theoretical studies of structures of neutral molecules and their anions as well as dissociative electron attachment properties are presented for the halomethanes of general formula CX(n) Y(m); X=H, F; Y=Cl, Br, I; n=0,4; m=4-n. The dissociative electron attachment seems to be the primary process resulting in toxicity of these species. The halomethane anions containing hydrogens are formed as radical-anion adducts. When H is replaced by F, these species become true sigma* radicals. The electron affinities are computed using a variety of computational techniques including the four-order M?ller-Plesset (MP4) technique that included 250 basis functions. It is challenging to compare the computed results with experiment due to dearth of experimental data and uncertainties in the existing experimental data. Thus in certain cases larger differences are found between the computed and experimental values. 相似文献
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Structures of protonated alane-Lewis base donor-acceptor complexes H2X2AlNHn(CH3)(3-n)+ (X = F, Cl, and Br; n = 0-3) as well as their neutral parents were investigated. All the monocations H2X2AlNHn(CH3)(3-n)+ are Al-H protonated involving hypercoordinated alane with a three-center two-electron bond and adopt the C(s) symmetry arrangement. The energetic results show that the protonated alane-Lewis complexes are more stable than the neutral ones. They also show that this stability decreases on descending in the corresponding periodic table column from fluorine to bromine atoms. The calculated protonation energies of HX2AlNHn(CH3)(3-n) to form H2X2AlNHn(CH3)(3-n)+ were found to be highly exothermic. The possible dissociation of the cations H2X2AlNHn(CH3)(3-n)+ into X2AlNHn(CH3)(3-n)+ and molecular H2 is calculated to be endothermic. 相似文献
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Bromotrinitrosyl iron was prepared by passing a stream of nitrogen monoxide over a mixture of iron dibromide and iron powder at elevated temperatures. It readily loses NO to give [(ON)2Fe(μ‐Br)Fe(CO)2]. The structure of freshly obtained [Fe(NO)3Br] was determined by X‐ray diffraction at 200 K and shows (distorted) tetrahedral coordination with N–Fe–N and N–Fe–Br angles of 107.9(2)° and 111.0(2)° and bent Fe–N–O groups (162.5(6)°). The DFT calculations in the series [Fe(NO)3X] (X = Cl, Br, I) reproduce well the experimental structural parameters and vibrational frequencies. 相似文献
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Sydora OL Henry TP Wolczanski PT Lobkovsky EB Rumberger E Hendrickson DN 《Inorganic chemistry》2006,45(2):609-626
A convenient synthesis of (t)Bu(3)SiSH and (t)Bu(3)SiSNa(THF)(x)() led to the exploration of "(t)Bu(3)SiSMX" aggregation. The dimer, [((t)Bu(3)SiS)Fe](2)(mu-SSi(t)Bu(3))(2) (1(2)), was formed from [{(Me(3)Si)(2)N}Fe](2)(mu-N(SiMe(3))(2))(2) and the thiol, and its dissolution in THF generated ((t)Bu(3)SiS)(2)Fe(THF)(2) (1-(THF)(2)). Metathetical procedures with the thiolate yielded aggregate precursors [X(2)Fe](mu-SSi(t)Bu(3))(2)[FeX(THF)]Na(THF)(4) (3-X, X = Cl, Br) and cis-[(THF)IFe](2)(mu-SSi(t)Bu(3))(2) (4). Thermal desolvations of 3-Cl, 3-Br and 4 afforded molecular wheels [Fe(mu-X)(mu-SSi(t)Bu(3))](12)(C(6)H(6))(n) (5-FeX, X = Cl, Br) and the ellipse [Fe(mu-I)(mu-SSi(t)Bu(3))](14)(C(6)H(6))(n) (6-FeI). Related metathesis and desolvation sequences led to wheels [Co(mu-Cl)(mu-SSi(t)Bu(3))](12)(C(6)H(6))(n) (5-CoCl) and [Ni(mu-Br)(mu-SSi(t)Bu(3))](12)(C(6)H(6))(n) (5-NiBr). The nickel wheel disproportionated to give, in part, [((t)Bu(3)SiS)Ni](2)(mu-SSi(t)Bu(3))(2) (7), which was also synthesized via salt metathesis. X-ray structural studies of 1(2) revealed a roughly planar Fe(2)S(4) core, while 1-(THF)(2), 3-Br, and 4 possessed simple distorted tetrahedral and edge-shared tetrahedral structures. X-ray structural studies revealed 5-MX (MX = FeCl, FeBr, CoCl, NiBr) to be wheels based on edge-shared tetrahedra, but while the pseudo-D(6)(d) wheels of 5-FeCl, 5-CoCl, and 5-FeBr pack in a body-centered arrangement, those of pseudo-C(6)(v)() 5-NiBr exhibit hexagonal packing and two distinct trans-annular d(Br...Br). Variable-temperature magnetic susceptibility measurements were conducted on 5-FeCl, 5-CoCl, 5-FeBr, and 6-FeI, and the latter three are best construed as weakly antiferromagnetic, while 5-FeCl exhibited modest ferromagnetic coupling. Features suggesting molecular magnetism are most likely affiliated with phase changes at low temperatures. 相似文献
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Velicković S Djordjević V Cvetićanin J Djustebek J Veljković M Nesković O 《Rapid communications in mass spectrometry : RCM》2006,20(20):3151-3153
Molecules of Li(n)X (n = 2, 3; X = Cl, Br, I) were examined with a magnetic sector mass spectrometer by surface ionization using a triple rhenium filament impregnated with fullerene (C60). The ionization energies obtained for Li(2)Cl, Li(2)Br and Li(2)I molecules are 3.8 +/- 0.1, 3.9 +/- 0.1 and 4.0 +/- 0.1 eV, respectively. The first ionization energy of Li(2)Cl is documented, while there are no literature data for the ionization energies of Li(2)Br and Li(2)I. The molecules of Li(3)Cl, Li(3)Br and Li(3)I were detected experimentally for the first time with ionization energies of 4.0 +/- 0.1, 4.1 +/- 0.1 and 4.1 +/- 0.1 eV, respectively. The ionization energies of Li(n)X (n = 2, 3; X = Cl, Br, I) are in correlation with the theoretical prediction of their hyperlithiated configurations. 相似文献
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On three-electron bonds and hydrogen bonds in the open-shell complexes [H2X2]+ for X = F, Cl, and Br
The [H2X2]+ (X = Cl, Br) formula could refer to two possible stable structures, namely, the hydrogen-bonded complex and the three-electron-bonded one. In contrary to the results published by other authors, we claim that for the F-type structures the hydrogen-bonded form is the only possible one and the [HFFH]+ complex is an artifact as its wave function is unstable. For all analyzed molecules, the IR anharmonic spectra have been simulated, which enabled a deeper analysis of other authors' published results of IR low-temperature matrix experiments. Topological atoms in molecules and electron localization function investigations have revealed that the nature of the bond in three-electron-bonded structures is similar to the covalent-depleted one in F2 or HOO molecules, but the effect of removing electrons from the bond area is stronger. 相似文献
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Open sheet and framework structures [CuX{cyclo-(MeAsO)4}] (X=Cl, Br, I) 1 – 3 and [Cu3X3{cyclo-(MeAsO)4}2] (X=Cl, Br) 4 and 5 may be prepared by self-assembly from CuX and methylcycloarsoxane (MeAsO)n in acetonitrile solution. 1 – 3 exhibit 44 nets in which (CuX)2 units are connected through μ-1 KAs1 : 2 KAs3 coordinated (MeAsO)4 ligands into large 28-membered rings. In contrast, adjacent [CuX] chains in 4 and 5 are connected into sheets by μ4-K4 As coordinated (MeAsO)4 building blocks, with μ-1 KAs1 : 2 KAs3 bridging of these layers by independent (MeAsO)4 cyclotetramers leading to the generation of a porous framework structure. 1 – 5 were characterised by X-ray structural analysis. 相似文献
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Mixtures of [Ph(3)PNPPh(3)](+)Cl(-) with CuBr(2) (or CuBr(2)+CuCl(2)) in ethanol/dichloromethane yield crystals containing three-coordinate copper(II) with mixed chloride and bromide ligands, namely [Ph(3)PNPPh(3)](+)[CuCl(0.9)Br(2.1)](-) (1) and [Ph(3)PNPPh(3)](+)[CuCl(2.4)Br(0.6)](-) (2). The trigonal-planar coordination of copper(II) is angularly distorted but unambiguous, as there is no other halide ligand within 6.7 A of the copper atom. Density functional theory (DFT) calculations on planar [CuClBr(2)](-) show that the energy surface for angle bending is very soft. Crystallisation in the presence of CH(3)CN yields [Ph(3)PNPPh(3)](+)[CuCl(0.7)Br(2.3)(NCCH(3))](-) (3), in which there is additional secondary coordination by NCCH(3) (Cu-N 2.44 A). DFT calculations of the potential energy surface for this secondary coordination show that it is remarkably flat (<3 kcal mol(-1) for a variation of Cu-N by 0.8 A). The crystal packing in 1, 2 and 3, which involves multiple phenyl embraces between [Ph(3)PNPPh(3)](+) ions and numerous C-H...Cl and C-H...Br motifs, is associated with intermolecular energies that are larger than the variations in intramolecular energies. For reference, the crystal structures of [Ph(3)PNPPh(3)(+)](2)[Cu(2)Cl(6)](2-) (4) and [Ph(3)PNPPh(3)(+)](2)[Cu(2)Br(6)](2-) (5) are described. We conclude 1) that three-coordinate copper(II) with monatomic halide ligands, although uncommon, can be regarded as normal, 2) that steric control by ligands is not necessary to enforce three-coordination, 3) that a hydrophobic aryl environment stabilises [Cu(Cl/Br)(3)](-), and 4) that the energy change in the transition from three- to four-coordinate copper(II) is very small (ca 5 kcal mol(-1)). 相似文献
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《Journal of Coordination Chemistry》2012,65(15):2356-2370
Technetium dimers Tc2(O2CCH3)4X2 (X =?Cl, Br) were synthesized and studied by X-ray Absorption Fine Structure spectroscopy (XAFS). EXAFS analysis gave for Tc2(O2CCH3)4Cl2: d Tc-Tc =?2.18(1) Å, d Tc–Cl =?2.43(1) Å and for Tc2(O2CCH3)4Br2: d Tc–Tc =?2.19(1) Å, d Tc-Br =?2.63(1) Å. The Tc Tc separations are in agreement with Raman studies while the Tc–X distances are somewhat larger. Comparison with other Tc(III) quadruply bonded dimers indicates that the carboxylate compounds exhibit larger Tc–Tc separations. The effect of the terminal ligand (nature and position) on the Tc–Tc separation is discussed. 相似文献
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Dr. Sergei I. Ivlev Konstantin Gaul Mengyi Chen Prof. Dr. Antti J. Karttunen Prof. Dr. Robert Berger Prof. Dr. Florian Kraus 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(22):5793-5802
[Br3][SbF6] and [Br3][IrF6] were synthesized by interaction of BrF3 with Sb2O3 or iridium metal, respectively. The former compound crystallizes in the orthorhombic space group Pbcn (No. 60) with a=11.9269(7), b=11.5370(7), c=12.0640(6) Å, V=1660.01(16) Å3, Z=8 at 100 K. The latter compound crystallizes in the triclinic space group P (No. 2) with a=5.4686(5), b=7.6861(8), c=9.9830(9) Å, α=85.320(8), β=82.060(7), γ=78.466(7)°, V=406.56(7) Å3, Z=2 at 100 K. Both compounds contain the cation [Br3]+, which has a bent structure and is coordinated by octahedron-like anions [MF6]− (M=Sb, Ir). Experimentally obtained cell parameters, bond lengths, and angles are confirmed by solid-state DFT calculations, which differ from the experimental values by less than 2 %. Relativistic effects on the structure of the tribromonium(1+) cation are studied computationally and found to be small. For the heaviest analogues containing At and Ts, however, pronounced relativistic effects are found, which lead to a linear structure of the polyhalogen cation. 相似文献