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91.
Hunks WJ Jennings MC Puddephatt RJ 《Chemical communications (Cambridge, England)》2002,(17):1834-1835
The first neutral, hybrid organic-inorganic coordination polymers with linear gold(I) centres in the backbone have the formula [X(OCH2CH2O2CCH2SAu)2(mu-dppee)]n, X = 1,4-C6H4 or C10H6, dppee = trans-bis(diphenylphospino)ethylene, are easily formed by self-assembly during crystallization from macrocyclic isomers (n = 1), and form sheet structures anchored by secondary Au...S and S...S interactions in the solid state. 相似文献
92.
Burchell TJ Eisler DJ Puddephatt RJ 《Dalton transactions (Cambridge, England : 2003)》2005,(2):268-272
Reaction of trans-[PdX2(SMe2)2](X = Cl or Br) with the chiral ligand LL = 1,1'-binaphthyl-2,2'-(NHC(= O)-3-C5H4N)2 gave the [2]catenane complexes trans-[{(PdX2)2(micro-LL)2}2], which are formed by self-assembly from 4 units each of trans-PdX2 and LL. The catenation is favored by the formation of multiple hydrogen bonds between the constituent macrocycles (4 x NHClPd, 2 x NHO double bond C). If the ligand LL is racemic, each macrocycle trans-[(PdX2)2(micro-LL)2] is formed in the meso form trans-[(PdX2)2(micro-R-LL)(micro-S-LL)] but the resulting [2]catenane is chiral as a direct result of the catenation step. This is the first time that this form of chiral [2]catenane has been observed. The enantiomers of the [2]catenane further self-assemble in the crystalline form, through secondary intermolecular PdX bonding, to form a racemic infinite supramolecular polymer of [2]catenanes. 相似文献
93.
The enthalpies of the reactions 1 and 2 have been determined as ΔH = Pt(PPh3)2(CPhCPh)cryst. + HClg → Pt(PPh3)2(Cl)(CPhCHPh)cryst. (1) Pt(PPh3)2(CPhCPh)cryst. + 2HClg → cis-Pt(PPh3)2Cl2cryst. + trans-CHPhCHPhg (2) ?90.2 ± 6 and ΔH = ?139.0 ± 16 kJ mol?1, respectively; dissociation energies of bonds involving platinum are expressed by the relationship: 41 kJ mol?1 + D(Pt-tolane) = 2D(PtCPhCHPh) = {D1(PtCl) + D2(PtCl)} ?350 kJ mol?1 相似文献
94.
M.J. Cooper A.K. Holliday P.H. Makin R.J. Puddephatt P.J. Smith 《Journal of organometallic chemistry》1974,65(3):377-382
207Pb chemical shifts are reported for the compounds (CH3)4?nPb Xn, where n = 1 · 4, X = 4-FC6H4; n = 1, 2, 4, X = CH3 CC; n = 1, 4, X = CH2CH; n = 1, X = Cl, CH3O, CH3CO2. A correlation between δ(207Pb) and δ(19F) for the 4-fluorophenyl derivatives is discussed, and solvent effects on δ(207Pb) for the propynyl derivatives are interpreted in terms of complex formation. 相似文献
95.
96.
Resorcinarene tetraphosphinite ligands, P4, react with silver(I) trifluoroacetate or silver(I) triflate, AgX, to give the corresponding [Ag4X4(P4)] complexes. The resorcinarene skeleton in these complexes adopts a boat conformation with the silver(I) phosphinite units on the horizontal, rather than the upright, arene units of the resorcinarene. The [Ag4X4(P4)] complexes react with free P4 ligand to yield the [Ag2X2(P4)] or [AgX(P4)] complexes, which are characterized in solution by NMR spectroscopy to have a conformation opposite to that of the [Ag4X4(P4)] complexes; the silver(I) phosphinite groups are on the upright arene rings of the resorcinarene "boat" instead of the horizontal arene units. There is an easy equilibrium between these complexes. When X = triflate, the [Ag4X4(P4)] complexes disproportionate and add aqua ligands during slow crystallization to give "capsule complexes", which are characterized crystallographically as [Ag10(O3SCF3)10(OH2)6(P4)2], [Ag10(O3SCF3)6(OH2)8(P4)2][O3SCF3]4, or [Ag13(O3SCF3)13(OH2)7(P4)2] depending on the resorcinarene tetraphosphinite ligand P4 used. These unusual capsule complexes are formed by the tail-to-tail self-assembly of pairs of [Ag4(P4)]4+ units linked by additional silver ions that bind to the phenyl substituents of one resorcinarene through {Ag(eta2-C6H5)}+ binding and to the bridging triflate ligands, aqua ligands, or both of the other resorcinarene unit. 相似文献
97.
LeClair P Swagten HJ Kohlhepp JT van De Veerdonk RJ de Jonge WJ 《Physical review letters》2000,84(13):2933-2936
Co/Al2O3/Co magnetic tunnel junctions with an interfacial Cu layer have been investigated with in situ growth characterization and ex situ magnetotransport measurements. Cu interlayers grown on Co give an approximately exponential decay of the tunneling magnetoresistance with xi approximately 0.26 nm while those grown on Al2O3 have a decay length of 0.70 nm. The difference in decay lengths can be explained by different growth morphologies, and in this way clarifies a present disagreement in the literature. For monolayer coverage of Cu, we show that the tunneling spin polarization is suppressed by at least a factor of 2 compared to Co and beyond approximately 5 ML it becomes vanishingly small. 相似文献
98.
Wong KL Chu MS Luce TC Petty CC Politzer PA Prater R Chen L Harvey RW Austin ME Johnson LC La Haye RJ Snider RT 《Physical review letters》2000,85(5):996-999
Experimental evidence is reported of an internal kink instability driven by a new mechanism: barely trapped suprathermal electrons produced by off-axis electron cyclotron heating on the DIII-D tokamak. It occurs in plasmas with an evolving safety factor profile q(r) when q(min) approaches 1. This instability is most active when ECCD is applied on the high field side of the flux surface. It has a bursting behavior with poloidal/toroidal mode number = m/n = 1/1. In positive magnetic shear plasmas, this mode becomes the fishbone instability. This observation can be qualitatively explained by the drift reversal of the barely trapped suprathermal electrons. 相似文献
99.
Focsa C Poclet A Pinchemel B Le Roy RJ Bernath PF 《Journal of Molecular Spectroscopy》2000,203(2):330-338
The A'(1)Pi-X(1)Sigma(+) near-infrared system of CaO was observed for the first time at high resolution using a Fourier transform spectrometer. The A'(1)Pi-X(1)Sigma(+) chemiluminescence was excited in a Ca + N(2)O flame produced in a Broida-type oven. More than 3000 rotational lines, classified into 19 bands involving the A'(1)Pi 0 = v' = 3 and the X(1)Sigma(+) 1 = v" = 7 vibrational levels were measured in the 4000-10 000 cm(-1) region with a precision of 0.005 cm(-1). The X(1)Sigma(+) (v = 0, 1) millimeter-wave and X(1)Sigma(+) (v = 0-3) infrared data available in the literature were merged with our new electronic data in order to obtain improved Dunham constants for the ground state of CaO. Very peculiar perturbations are observed in the higher vibrational levels of the A'(1)Pi state, so the upper levels of transitions with v' = 2 and 3 were represented by term values in our least-squares analysis. The interaction of the A'(1)Pi (v >/= 2) levels with the nearby b(3)Sigma(+) (v-2) levels has been detected. An extended set of A'(1)Pi (v = 0-3) data has been obtained which is suitable for use in a future multistate deperturbation analysis of the a(3)Pi approximately A'(1)Pi approximately b(3)Sigma(+) approximately A(1)Sigma(+) complex of excited states. The new near-infrared spectra of the A'(1)Pi-X(1)Sigma(+) transition of CaO also permits the first direct high-resolution linkage between the orange and green systems and the near-infrared bands. Copyright 2000 Academic Press. 相似文献
100.
McArdle CP Irwin MJ Jennings MC Puddephatt RJ 《Angewandte Chemie (International ed. in English)》1999,38(22):3376-3378
The value of n in Ph(2)P(CH(2))(n)PPh(2) controls whether a simple ring or a [2]catenane is formed in the reaction with a digold(I) diacetylide. Simple macrocyclic gold complexes are obtained for n=2 and the family of organometallic [2]catenanes for n=4 and 5 (see structure); a mixture of these products as well as a third isomer results when n=3. 相似文献