Heteronuclear clusters

The red tetrathiomolybdate ion appears to be a principal participant in the biological Cu—Mo antagonism and is reactive toward other transition-metal ions to produce a wide variety of heteronuclear transition-metal sulfide complexes and clusters (13,14). For example, tetrathiomolybdate serves as a bidentate ligand for Co, forming Co(MoSTetrathiomolybdates and their mixed metal complexes are of interest as catalyst precursors for the hydrotreating of petroleum (qv) (15) and the hydroHquefaction of coal (see Coal conversion processes) (16). The intermediate forms MoOS Mo02S 2> MoO S have also been prepared (17). 

Heteronuclear Carbonyls and High Nuclearity Carbonyl Clusters... 

In addition to the heteronuclear clusters considered in the preceding paragraphs. As, Sb and Bi also form homonuclear clusters. We have already seen that alkaline earth phosphides M3P14 contain the [Pv] cluster isoelectronic and isostructural with P4S3, and the analogous clusters [Asy] " and [Sbv] have also been synthesized. Thus, when As was heated with metallic Ba at 800° C, black lustrous prisms of BasAs were obtained, isotypic with Ba3Pi4 these contained the [Asv] anion with dimensions as shown in Fig. 13.25(a).Again,... 

Heteronuclear clusters can be prepared by the reduction of AuClPPhj with Cs3V(CO)5 or Au(N03)PPh3 with [Ir2(M-H)3(H)2(PPh3)4)[PF6], which yield, respectively, (AuPPhjIjVfCOj and [Au3lr(N03XPPh3)5][PFj. 

Heteronuclear Gold Cluster Compounds D. Michael P. Mingos and Michael J. Watson... 

The heteronuclear cluster [Mo3CoS4(H2O)10]4+ has been reported, where the Co is formally zerova-lent.168 The core structure (18) features two edge-linked cubane units with Co—S bridging the two clusters. 

Various homo- or heteronuclear cluster species which contain both a- and 7r-bonded alkynyl groups have been synthesized and characterized, e.g., [Ag5(C=CPh)6]-,278... 

Heteronuclear compounds containing gold(I) and other metal atoms which present Au -M interactions are well represented in the area of metal carbonyl clusters. The addition of a AuPR3+ or Au2(/u-P-P)2+ fragment to a metal cluster results in the formation of Au—M bonds often with retention of the cluster framework. Several reviews have been reported recently,3153-3155 and so it will not be treated here. Some representative examples are found in Figure 26. 

Pignolet, L. H. Krogstad, D. A. The Heteronuclear Cluster Chemistry of the Group 11 Metals—Some Recent Advances. In Gold, Progress in Chemistry, Biochemistry and Technology Schmidbaur, H., Ed. Wiley Chichester, U.K., 1999, pp 429-493. 

Adamantoid systems [(//-ChR)6(MX)4]2 (Ch = S, Se, Te R usually Ph M = Cd, Hg X = halogene) have been prepared and studied by X-ray structure analyses, heteronuclear NMR and vibrational spectrometries, and partly by UV/vis spectrometry.337-341 Meanwhile, the systems have been expanded to superadamantoid clusters with four fused adamantoid subunits [MioCh ChPh fTPhAd342 343 and related clusters,344 and finally to nanoclusters with up to 32 metal atoms in one cluster.34, 3 6... 

The novel T 2- X2-SiO bonding mode observed in these heterometallic complexes may have relevance to the stabilization of unsaturated, catalytically active heteronuclear systems. It also provides a new structural model for the bonding of small clusters or aggregates onto silica [1], a dominant theme in heterogenous catalysis. 

A further point of interest is their ready interconversion in solution, which we have studied by variable temperature n.m.r. measurements (8). Reaction of [(n-C5H5)(0C)2W =CR] with polynuclear metal carbonyl species is likely to afford many new heteronuclear cluster compounds containing tungsten. 

More recently, Adams and coworkers have provided a very interesting case of heteronuclear clusters that are very active for the hydrogenation of alkynes [4, 54, 55]. The high-nuclearity layer-segregated Pt-Ru complex [Pt3Ru6(CO)21(jU3-H)(/ -H)j], consisting of three stacked triangular layers of metal atoms with an... 

Metal bromides, 4 322-330 Metal can food packaging, 18 37-39 Metal-carbene complexes, 26 926 Metal-carbon compounds, 4 648, 650 Metal-carbon eutectic fixed points, 24 454 Metal carbonyl catalysts, supported, 16 75 Metal carbonyl complexes, 16 73 Metal carbonyls, 15 570 16 58-78 bonding and structure of, 16 59-64 from carbon monoxide, 5 12 in catalysis, 16 72-75 economic aspects of, 16 71 health and safety aspects of, 16 71 heteronuclear, 16 69-71 high nuclearity, 16 66-69 high nuclearity carbonyl clusters, 16 64-66... 

Trinuclear Carbonyls and Substituted Carbonyls for Heteronuclear Clusters... 

This field has developed at a rapid pace since 1968, and a wide range of heteronuclear complexes of the tri- and tetranuclear variety has been established. It will be convenient to discuss the compounds in the first instance on the basis of nuclearity and, for the tetranuclear species, to subdivide the discussion on the basis of the carbonyl stoichiometry and cluster electron count. We have excluded from the discussion the interaction with nontransition elements, such as Hg, Tl, and Cd, which form a wide range of compounds. 

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