Carbonyl clusters tetranuclear

The tetranuclear derivatives are classified as derivatives of the three principal carbonyl cluster units observed, H4M4(CO)12, H2M4(CO)13, and MjCCOlxs, with a final group involving bonding to platinum or gold. 

We are pleased to accept the invitation of the editors to present a review on metal carbonyl clusters which affords us the opportunity to discuss the tetranuclear clusters and to complete the previous discussion of 3-dimensional clusters60. ... 

Table 2. Mixed Tetranuclear Carbonyl Clusters (each compound is discussed in the section shown in parentheses)... 

The available structural data on the tetranuclear carbonyl clusters are summarized in Table 6. 

The preparation and ESR measurements of two tetranuclear carbonyl cluster radical anions have been reported . [Ir4(CO)12] , (g = 2.002) 208 and [Fe4(C0)4Cp4], ... 

As already shown in Eqs. (3), (4) and (5), fragmentation of carbonyl cluster anions, on reaction with carbon monoxide becomes easier with increasing negative charge. It is therefore not surprising that reduction of tetranuclear clusters with alkali metals in excess, gives rise to simple mononuclear derivatives [M(CO)4]-, as found for Co4(CO)12 in liquid NH3 13, e Rh4(CO)12 in THF under C056) and Ir4(CO)12 in THF under CO 17S ... 

Contents P. Chini, B. T. Heaton Tetranuclear Carbonyl Clusters. 

Tetranuclear clusters Pt4(CO)5L4 and Pt4(CO)5L3 have been prepared from the reaction of CO on the trinuclear species.336,347 For tetrametallic compounds examples are found with Pt2Mo2, Pt2Co2 and Pt2M2 (M = Cr, Mo, w).348,349 These latter complexes show an irreversible two-electron reduction leading to the rupture of the metallic core into identified fragments. These complexes are of the type [PtM(jU3-CO)(ji2-CO)2Cp(PPh3)]2, and the first two oxidation waves indicate one-electron processes.349 A tetrametallic carbonyl cluster PtOs3(fi-H)2(CO)io(PR3) has also been characterized.350... 

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