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Dinuclear organometallics bonds

As an illustrative example taken from the current literature, consider the variation of C-C and C-O bond lengths in the deltate species CsO2- held within a dinuclear organometallic uranium(IV) complex. In a remarkable synthesis, this cyclic aromatic oxocarbon dianion is generated by the metal-mediated reductive cyclotrimerization of carbon monoxide, as indicated in the reaction scheme... [Pg.524]

Because of the great strength of iridium-iridium bonds, there is a wealth of information on polynuclear metal-carbonyl cluster compounds of iridium (see Dinuclear Organometallic Cluster Complexes mA Polynuclear Organometallic Cluster Complexes). It4(CO)i2 (45) may be synthesized from... [Pg.1859]

In general, high-oxidation state complexes have far fewer than 18 electrons becanse extreme steric crowding would result if enough ligands were bonded to the metal center to form either a 17- or 19-electron species. Similarly, dimerization to generate cluster-type complexes is often prevented for steric reasons see Dinuclear Organometallic Cluster Complexes). [Pg.3591]

Electrochemical techniques have also been applied to determining metal-metal bond energies in dinuclear organometallic molecules (44). Using a combination of redox equilibration experiments with reagents of known potentials and fast scan cyclic voltammetry, it is possible to obtain E° data for the kinds of reactions shown in Equations 33 and 34, respectively. The result is the free energy (but not the... [Pg.8]

M-H bonds are sufficiently weak that hydrides can also transfer H to C-C double bonds. Examples of H acceptors include methyl methacrylate, a-methylstyrene, and the dinuclear organometallic complex in Figure 3.39. The resulting radicals must be stabilized in order for H transfer to proceed at an appreciable rate. [Pg.133]

Barckholtz and Bursten have released Part 1 of a (hopefully) larger study of density functional calculations of dinuclear organometallic carbonyl complexes. This part deals with metal-metal and metal-CO bond energies. [Pg.173]

Porter, L.C. and Fackler, J.P. Jr (1986) Structure of the first example of an organometallic dinuclear gold(II) complex possessing bonds to oxygen. Acta CrystaUographica, 42, 1128-1131. [Pg.40]

DR. ANTHONY POE (University of Toronto) As Dr. Geoffroy mentioned, there is a fair bit of work being done on dinuclear metal-metal bonded carbonyls but rather less on metal clusters [Geoffroy, G. L. Wrighton, M. S., "Organometallic Photochemistry," Academic Press New York, 1979]. We have been interested for some time in the thermal fragmentation of metal clusters, and have recently looked at some photochemical reactions as well. I would like to present some results here today which are very preliminary. [Pg.377]

The extended Hiickel method, which is a semiempirical quantum chemistry method, is often used as a preliminary step in the DFT study of molecular orbital analysis. The acetylide-bridged organometallic dinuclear complexes 5.2 were studied by Halet et al. using the extended Hiickel method for qualitative analysis and DFT for additional electronic properties [97], The extended Hiickel analysis concluded that the main contribution of the Pt-C bond arises from ct type interactions while the n back-donation is very weak. The DFT/BP86 calculation gives a 2.371 eV HOMO-LUMO gap. The electronic communication parameter Hdb between the bis-ferrocene compound linked with platinum acetylide (5.3) was calculated to be 0.022 eV, compared with 0.025 eV obtained experimentally by Rapenne and coworkers using DFT and the extended Hiickel method [98],... [Pg.182]


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Dinuclear

Dinuclear organometallics

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