Oxides with trinuclear clusters

Tungsten pentachlofide [13470-13-8], WCl, mp 243°C, bp 275.6°C, is a black, crystalline, deHquescent soHd. It is only slightly soluble in carbon disulfide and decomposes in water to the blue oxide, 200 2. Magnetic properties suggest that tungsten pentachlofide may contain trinuclear clusters in the soHd state, but this stmcture has not been defined. Tungsten pentachlofide may be prepared by the reduction of the hexachloride with red phosphoms (9). 

Ceruloplasmin is involved in copper storage and transport as well as in iron mobilisation and oxidation. Among the blue oxidases it is unique since it contains, in addition to the usual motif of a type 1 combined with the trinuclear cluster, two other type 1 coppers. Electron transfer occurs, however, only between five of the six copper ions since one of the type 1 centres is not catalytically relevant due to its too high redox potential. The redox potentials of the centres were determined and possible electron transfer pathways among the copper sites were discussed.101... 

There are three important routes to the formation of the mercury-transition metal bond (a) displacement of halogen or pseudohalogen from mercury(II) salts with carbonyl metallate anions (b) reaction of a halo-phenylmercury compound with a transition metal hydride and (c) oxidative addition of a mercury halide to neutral zero valent metals.1 We report here the syntheses of three compounds containing three-centre, two-electron, mercury-ruthenium bonds utilizing trinuclear cluster anions and mercury(II) halides.2-4... 

Phthalic acid, with trinuclear Os clusters, 6, 743 n-acceptor carbon ligands, in molybdenum carbonyls, 5, 455 Ti-allyl complexes, with molybdenum with cyclopentadienyl-supporting ligands, 5, 544 monomeric complexes, 5, 546 oxide surface binding, 5, 546... 

A catalyst for cyclohexane oxidation with /-BuOOH has been designed by immobilization of a well-defined trinuclear Co cluster in a MCM-41 with covalently bound glycine ligands. Particularly high selectivities for cyclohexanone were obtained (170). 

It is in this oxidation state that the known chemistry of the two elements is most different. For rhenium di- and trinuclear cluster species predominate (Section 18-D-5), whereas for Tc there are only a few Tc and no Tc3+ complexes. Mononuclear Tc3+ species do occur. The only simple [MXJ3- complex known for either element is the [Tc(NCS)6]3 ion, but the mer-MCl3(PR3)3, MCl3py3, and [MX2(LL)2]+ complexes with X = halide, NCS , or MeS" and LL a diphosphine or diarsine are important.41 Some of these complexes can be reduced with retention of structure in the II and even I oxidation states.42... 

Au(I) can form uninuclear complexes with tris(dimethylamino)phosphane (98), or can form trinuclear cluster cations with oxide (99) or imido (100) divalent anions. The P—Au—X atoms are nearly collinear in complexes 99 and 100, the O and N atoms are at die apex of a pyramid with AU3 basis198. See also items N-3 and N-4 above. 

---