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991.
Qian-Feng Zhang Yu-Jie Liu Richard D. Adams Alexander Rothenberger Dieter Fenske Wa-Hung Leung 《Journal of Cluster Science》2006,17(3):445-455
Treatment of tetracopper(I)-phosphonitocavitand [1·Cu4(μ-Cl)4(μ4-Cl)] (2) (1 = tetraphosphonitocavitand [rccc-2,8,14,20-tetrakis-(iso-butyl)-phosphonitocavitand (C44H48O8P4Ph4)]) with PhSeSiMe3 in THF at low temperature afforded a novel polyanionic cluster [pyH]6[(CuCl)9(μ3-SePh)5(μ4-SePh)] (4) as a major product along with a new tetracopper(I)-phosphonitocavitand (3) with a centered μ3-Cl. Molecular structure of anionic cluster in 4 consists of six PhSe− bridging ligands containing five μ3-SePh and one exceptional μ4-SePh bridging nine copper atoms, of which eight copper atoms have trigonal coordination geometry and the other has distorted
tetrahedral geometry.
Dedicated to Professor Han-Qin Liu on the occasion of his 70th birthday. 相似文献
992.
Four dithiooxalato (Dto) bridged one-dimensional Ni(ll) and Ni(ll)Cu(ll) complexes (Me6[14]dieneN4)Ni2(Dto)2) (1), (Me6[14]dieneN4)CuNi(Dto)2 (2), (Me6[14]aneN4)Ni2(Dto)2 (3), and (Me6[14]aneN4)CuNi(Dto)2(4), were synthesized. These complexes have been characterized by elemental analysis, IR, UV and ESR spectra. The crystal structure of complex 3 was determined. It crystallizes in the monoclinic system, space group C2/c with a = 2.2425(4) nm, b = 1.0088(2) nm, c=1.4665(3) nm, β= 125.32(3)° ;Z=4; R = 0.076, Rw = 0.079. In the complex, Ni(1) coordinates four sulphur atoms of two Dto ligands in plane square environment. Ni(2) lies in the center of mac-rocyclic ligand. For Dto ligand, two sulphur atoms coordinate Ni(1), and O(1) coordinates Ni(2) and forms weak coordination bond. O(2) is linked to N(2) of macrocyclic ligand through hydrogen bond. 相似文献
993.
Qing-Lun Wang Li-Na Zhu Dai-Zheng Liao Shi-Ping Yan Zong-Hui Jiang Peng Cheng Guang-Ming Yang 《Journal of Molecular Structure》2005,754(1-3):10-15
A new oxamato-bridged NiIICuIINiII species, [Ni(tacn)(H2O)]2[μ-Cu(pba)](ClO4)2·6H2O 1, (tacn=1,4,7-triazacyclononane; pba=1,3-propylenebis(oxamato)) has been synthesized and structurally as well as magnetically characterized. Complex 1 has a discrete trinuclear NiIICuIINiII structure: Two nickel(II) ions are bridged by [Cu(pba)]2− anion, macrocyclic ligand tacn works as terminal ligand of the nickel(II) center. The magnetic data of compound 1 was analyzed by means ofleading to gCu=2.19, gNi=2.18, J=−112.8 cm−1, D=±4.31 cm−1. The parameters are compared with the similar complexes and the irregular spin state structure of complex 1 is also described here. 相似文献
994.
Balandina A Kalinin A Mamedov V Figadère B Latypov S 《Magnetic resonance in chemistry : MRC》2005,43(10):816-828
(1)H, (13)C and (15)N NMR chemical shifts for a variety of novel quinoxalines were determined by different 2D methods and were calculated using the GIAO DFT approach. Comparison with experimental data shows good correlations in the case of (1)H, (13)C and (15)N chemical shifts. Different combinations of basis sets were tested. In non-polar solvents quinoxalines exist as dimers owing to strong hydrogen bonding. Calculations for dimers improve the correlation between experiment and theory. Additive empirical methods for estimating chemical shifts have drawbacks and have to be used with a great care for this type of compound. 相似文献
995.
Jos Ruiz M. Teresa Martínez Consuelo Vicente Venancio Rodríguez Gregorio Lpez Jos Prez Penny A. Chaloner Peter B. Hitchcock 《无机化学与普通化学杂志》2005,631(11):2227-2231
Mononuclear palladium‐hydroxo complexes of the type [Pd(N–N)(C6F5)(OH)][(N–N) = 2,2′‐bipyridine (bipy), 4,4′‐dimethyl‐2,2′‐bipyridine (Me2bipy), 1,10‐phenantroline (phen) or N,N,N′,N′‐tetramethylethylenediamine (tmeda) react with phenols ArOH in tetrahydrofuran giving the corresponding aryloxo complexes [Pd(N–N)(C6F5)(OAr)]. Elemental analyses and spectroscopic (IR, 1H and 19F) methods have been used to characterize the new complexes. The X‐ray crystal structure of [Pd(tmeda)(C6F5)(OC6H4NO2‐p)] has been determined. In the crystal packing the planes defined by two C6H4 rings show a parallel orientation. There are also intermolecular C–H···F and C‐H···O hydrogen bonds. 相似文献
996.
The reactions of a range of 2-arsa- and 2-stiba-1,3-dionato lithium complexes with group 4-7 metals have been investigated. These have given rise to several complexes in which an arsadionate acts as a chelating ligand; [V{η2-O,O-OC(But)AsC(But)O}3], [M{η2-O,O-OC(But)AsC(But)O}2(DME)], M=Cr or Mn; or as an η1-As-diacylarsenide, [MnBr(CO)4{As[C(O)But]2Li(DME)}]2. In addition, reactions of lithium arsadionates with TaCl5 have led to metal mediated arsadionate decomposition reactions and arsadionate oxidative coupling reactions to give the known arsaalkyne tetramer, As4C4But4, and the new tetraacyldiarsane, [{As[C(O)Mes]2}2] Mes=mesityl, respectively. The treatment of several lithium arsadionates with [MoBr2(CO)2(PPh3)2] has also initiated arsadionate decomposition reactions and the formation of the metal carboxylate complexes, [MoBr(CO)2{η2-O2C(R)}(PPh3)2] R=But, Ph, Mes. The X-ray crystal structures of six of the prepared complexes are discussed. 相似文献
997.
We formulate a Hartree–Fock‐LAPW method for electronic band structure calculations. The method is based on the Hartree–Fock–Roothaan approach for solids with extended electron states and closed core shells where the basis functions of itinerant electrons are linear augmented plane waves. All interactions within the restricted Hartree–Fock approach are analyzed and in principle can be taken into account. In particular, we obtained the matrix elements for the exchange interactions of extended states and the crystal electric field effects. To calculate the matrix elements of exchange for extended states, we first introduce an auxiliary potential and then integrate it with an effective charge density corresponding to the electron exchange transition under consideration. The problem of finding the auxiliary potential is solved by using the strategy of the full potential LAPW approach, which is based on the general solution of periodic Poisson's equation. Here, we use an original technique for the general solution of periodic Poisson's equation and multipole expansions of electron densities. We apply the technique to obtain periodic potentials of the face‐centered cubic lattice and discuss its accuracy and convergence in comparison with other methods. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002 相似文献
998.
P. Thuéry M. Nierlich C. Bressot V. Lamare J. F. Dozol Z. Asfari J. Vicens 《Journal of inclusion phenomena and macrocyclic chemistry》1995,23(4):305-312
The crystal structures of two binuclear complexes between caesium and 1,3-calix[4]-bis-crowns have been determined. Cs2
Bis-benzoC6(NO3)2. 3CHCl3 (1) in whichBis-benzoC6 is 1,3-calix[4]-bis-benzo-crown-6, crystallizes in the orthorhombic system: space groupPca2
1 a=19.513(10),b=15.382(5),c=23.708(9) Å,V=7116(5) Å3,Z=4. Refinement led to a final conventionalR value of 0.065 for 2321 reflections. The structure of (1) is analogous to those already reported withBis-C6, (in whichBis-C6 is, 1,3-calix[4]-bis-crown-6) and NO
3
–
as a counter-ion. Cs2
Bis-C6(NCS)2 (2) crystallizes in the monoclinic system: space, groupC2 a=36.57(2),b=11.47(1),c=13.65(1) Å, =109.03(5)°.,V=5415(6) Å3,Z=4. Refinement led to a final conventionalR value of 0.063 for 2227 reflections. Compound (2) is made of dimers bridged by a disordered NCS– ion. The crown ether chain conformations are discussed.
Supplementary data relating to this article (atomic coordinates, anisotropic displacement parameters, bond distances and angles and observed and calculated structure factors) are deposited with the British Library as Supplementary Publication No. SUP 82199 (52 pages). 相似文献
999.
M. Broschag T. M. Klaptke A. Schulz I. C. Tornieporth-Oetting P. Umbach P. S. White 《无机化学与普通化学杂志》1994,620(6):1132-1136
Fluorination of Cyanuric Chloride and Low-Temperature Crystal Structure of [(ClCN)3F]+[AsF6]? The low-temperature fluorination of cyanuric chloride, (ClCN)3, with F2/AsF5 in SO2F2 solution yielded the salt [(ClCN)3F]+ [AsF6]? ( 1 ) essentially in quantitative yield. Compound 1 was identified by a low-temperature single crystal X-ray structure determination: R 3 c, trigonal, a = b = 10.4246(23) Å, c = 15.1850(24) Å, V = 1429.1(4) Å 3, Z = 6, RF = 0.056, Rw = 0.076 (for significant reflections), RF = 0.088, Rw = 0.079 (for all reflections). Fluorination of neat (ClCN)3 with [NF4]+ [Sb2F11]? yielded NF3, CClF3, SbF3, N2 and traces of CF4. A qualitative scale for the oxidizing strength of the oxidative fluorinators NF4+ and (XCN)3F+ (X = H, F, Cl) has been computed ab initio. 相似文献
1000.
A New Samarium Nitride Sulfide: Sm4N2S3 The oxidation of samarium with sulfur in the presence of SmCl3 and NaN3 as nitrogen source (molar ratio: 12:9:4:2, evacuated silica vessel, some NaCl as flux, 850°C, 7 d) yields Sm4N2S3 as lath-shaped, dark red single crystals. The by-products (NaCl and NaSm2Cl6) are rinsed with water from the crude product. The crystal structure of Sm4N2S3 (monoclinic, C2/m (no. 12), Z = 2, a = 1 318.04(12), b = 391.57(2), c = 1 031.76(9) pm, β = 130.874(6)°, R = 0.036, Rw = 0.031) contains two crystallographically different Sm3+, both in sixfold coordination of the anions. Besides distorted octahedra [(Sm1)N3S3] and [(Sm2)NS5], tetrahedra [(N3?)(Sm)] connected via two cis-oriented edges to form chains [N(Sm1)3/3(Sm2)1/1]3+ build up the Mayn structural feature. These are arranged in the fashion of a closest packing of rods and held together by two crystallographically different S2? anions which take care for charge neutrality and three-dimensional interconnection. 相似文献