Showing papers in "Polyhedron in 1988"

TL;DR: In this paper, the homogeneous Ziegler-Natta catalyst, consisting of zirconocene compounds and methylalumoxane, leads to extremely high polymerization activities, and polyethylene with activities up to 40 x 106 g PE/g Zr·h is formed.

TL;DR: In this article, the authors proposed to remove the ligand sphere together with the outer shell of metal atoms to generate the inner naked M13 nuclei, which are metastable and build up novel structures.

TL;DR: In this article, the authors presented images that show columns or layers of cluster molecules with a distance of 2.1± 0.1 nm, including the ligand shell and of the naked cluster.

TL;DR: In this paper, the periodic trends of simple transition metal species as determined by guided ion beam mass spectrometry are reviewed with an eye on developing ways of applying the data to condensed phase species.

TL;DR: The presence of Cu retards the transformation of ferrihydrite (5Fe 2 O 3 · 9H 2 O) into crystalline products Low levels of Cu (9 mol%) suppress formation of goethite [(α-FeO(OH)] and lead to a product consisting entirely of haematite as mentioned in this paper.

TL;DR: In this article, the full details of product, kinetic and CoC5′ bond dissociation energy studies of the thermolysis of AdoB 12 in ethylene glycol are presented.

TL;DR: In this paper, a review of the literature of radical cage effects in solution is presented, and the available evidence for the operation of solvent cage effect in organotransition metal chemistry is summarized.

TL;DR: In this paper, the first results of aldehydes are produced due to the presence of the rhodium center. But when L is a triphenylphosphine ligand no more than 85% of linear aldehyde is obtained for a full selectivity of the conversion of alkenes into the corresponding aldeenes, the major effect observed is electronic.

TL;DR: In this article, the authors discuss recent results from their laboratory on the chemistry, photochemistry and thermodynamics of simple metal-ligand ionic species in the gas phase using laser desorption coupled to Fourier transform mass spectrometry, and successfully generated numerous highly unsaturated metal ions including bare metal carbenes, methyls, hydrides, nitrenes and amides.

TL;DR: In this paper, the strength of metal ligand bonds in early and late transition metal systems was analyzed in terms of electronic and steric factors, and the order of the D (TiL) bond strength was calculated to be O(453) > OCH 3 (427) > CN(410) > NH 2 (365) > SH(283) > CH 3 (268) > H(251) > SiH 3 (211) > PH 2 (191) >

TL;DR: In this article, the dinuclear cluster [Re2(pyS)2(CO)6] contains three fused four-membered rings, which can be easily cleaved by ligand addition and in redistribution reactions with Re2(MepyS) 2(CO), the 6-methyl-substituted derivative for which the X-ray structure is reported.

TL;DR: In this article, the relationship between the intermolecular oxidative addition reaction of carbon-hydrogen bonds in organic molecules to transition metal centres, and the dissociation energies of the CH, MH, and MR bonds that undergo changes during this process is discussed.

TL;DR: An efficient procedure for the preparation of 4,4′,4″-tri- tert -butylterpyridine (trpy*) which is formed together with 4, 4′-di- tert-butylbipyridine(bipy*) is described in this paper.

TL;DR: In this article, the molecular structure of [Zr(NMe2)4]2 has been determined by an x-ray study and shown to involve a central Zr2N8 moiety involving the fusing of two trigonal bipyramidal units along a common axial-equatorial edge.

TL;DR: In this article, all isomers of (Ph2P)nC6H6−n (n = 1-4) have been prepared by the reaction between the corresponding isomer of C6H 6−nFn and Ph2PNa in liquid ammonia.

TL;DR: In this article, the equilibria in aqueous solution in the system L -alanine+VO 2+ have been studied by a combination of pH-potentiometric and spectroscopic methods (EPR, visible absorption and circular dichroism) in the pH range 1.5-13.

TL;DR: In the presence of oxygen, [Fe(CN)4NO]2− can reform as mentioned in this paper to give an effective stoichiometry of RS− to [Fe[CN]5NO]-2− substantially greater than 1 : 1 ; in the absence of oxygen and with a stoichiometric ratio of 1: 1, the [Fe{4NO}2− follows a well established pathway to yield [Fe·6]4−, Fe2+ and NO.

TL;DR: In this paper, the authors used SiO2-supported carbonyl clusters as molecular precursors for tailored bimetal catalysts, which exhibited high activity and selectivities for C1 + C2 alcohols in a CO + H2 reaction and higher alcohols for olefin hydroformylation.

TL;DR: Hexamethyldisiloxane is a useful reagent for the convenient, high yield preparation of oxyhalide derivatives of molybdenum and tungsten as discussed by the authors.

TL;DR: In this article, the relative bond dissociation energies (BDEs) have been obtained by equilibrating early transition metal alkyls and hydrides with H2 or the CH bonds of hydrocarbons.

TL;DR: In this paper, the Diamagnetic Technetium(V) complexes of general formulae [TcNX 2 (Ph 3 Y) 2 ] and [T cNX 3 (Me 2 PhP) 3 ] (X = Cl, Br; Y = P, As) were prepared starting from TcCl 4 − and TcNBr 4 −, respectively and characterized.

TL;DR: The following adducts of Group III trialkyls with phosphines have been prepared, either by direct reaction in hydrocarbon solution or by displacement of ether from the metal Trialkyl etherate: Me3M·PPh3 (M = Ga, In); Me3In·P(2-MeC6H4)3; (R3M)2·(Ph2PCH2)2 (R

TL;DR: In this paper, the new Fe(III), Co(II), Ni(II, Cu(II) and Zn-II complexes with tridentate Schiff base, the product of condensation of o-aminobenzyl alcohol with salicylaldehyde have been synthesized and characterized by elemental analysis, IR, electronic, EPR and Mossbauer spectra.

TL;DR: In this article, the reaction of a cyclopentadienide with a metal halide was used to obtain the THF-soluble complexes (C5H5)2Ca(THF)2 and (Me5C5) 2M(THFs)2 (M = Ca, Sr, Ba).

TL;DR: In this paper, a linear correlation of LnMX to HX BDEs was found for the two dissimilar metal centres for phosphine dissociation from Cp(PMe3)2RuX complexes and suggest the principle of functional group additivity has limited applicability in organometallic thermochemistry.

TL;DR: The N8 crytand was obtained in good yield by a Schiff-base condensation of tris(2-amino ethyl)amine with terephthalaldehyde, and X-ray crystal structure determination of the disilver(I) cryptate revealed distorted tetrahedral coordination for Ag+ and an internuclear AgAg distance of 6.06 A.

TL;DR: In this paper, the authors proposed a method for determining transition metal-alkyl bond dissociation energies in solution using free radical traps and showed that the free radical trap can be used to determine the activation enthalpies of the homolytic bond reaction and reverse (recombination) reaction.