Alkoxides polynuclear complexes

Scheme 3 Syntheses of metal alkoxide polynuclear complexes [110, 115]...

In this way, alkoxides, glycolates, catecholates, carboxylates, or Schiff base complexes have been obtained.37,38 Other metal chelates have been synthesized by electro-oxidation of the bare metal electrode phosphido, azolates, phthalocyanines, semicarbazides, Schiff bases, etc.37 In addition to the syntheses of monometallic complexes, electrochemistry has been proven to yield polynuclear complexes by using assembling or multidentate ligands.37... 

The second t)q)e of cluster compounds of the lanthanide alkoxides features one or several small-unit, inorganic ligands including oxo, hydroxo, halo, and other groups as part of the cluster core structure. Frequently, a combination of such ligands is foimd in the same cluster species. In a sense, this "central spherical charge density" drives the assembly of the polynuclear complexes without their participation, no clusters are formed or species of completely different structures result. 

These complexes ure chemically like polynuclear metal carbonyl complexes (class I) but are included here instead of in Chapter 15 because they do not possess metal-carbon bonds. A rich chemistry has been developed in which alkoxides Func-... 

Copper(I) Carboxylates, Triflate, Alkoxides, and Dialky lamides. Thecarbox-ylates have varied structures. The acetate that is obtained as white air-sensitive crystals by reduction of Cu11 acetate by Cu in pyridine or MeCN has a planar chain structure (17-H-I). By contrast the trifluoroacetate [Cu02CCF3]4-2C,H6, and benzoate [Cu02CPh]4 complexes are tetramers with bridging carboxylates as in (17-H-II). This is only one type of Cut polynuclear structure (see later). There are also bridged pyrazole and pyrazolylborate compounds. 

Thompson, M.K.,Lough, A.J.,White, A.J.P.,Ws, D.J., andKahwa, 1. A. (2003) Eormation of two diverse classes of polyamino-alkoxide chelates and their mononuclear and polynuclear lanthanide(lll) complexes. Inorganic... 

The C-0 bond can be more easily activated when the CO molecule interacts with more than two metal atoms. Recently, the dissociative adsorption of carbon monoxide by polynuclear metal complexes, such as [(silox)2TaH2]2 (Eq. 57) [126, 127] and [(silox)2WCl]2 (Eq. 58) [126-129], and tetratungsten alkoxides [129] has been achieved. Hydrogenation of CO to give hydrocarbons promoted by metal clusters has been reviewed [130]. 

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