Synthesis and structural characterization of hybrid Group 12, 14, 15 metals-molybdenum (tungsten) cluster compounds

For the heterometallic cluster compounds containing a core of [M3YS3M')((4 + n)+) (M = Mo, W; Y = O, S; M'= metal atom except Mo, W), a relatively comprehensive understanding has already been made when M'(n +) appears to be a transition metal. When M'(n +) is a main group metal, however, what will be the situation? This certainly arouses the interest among the chemists. In this present work, the synthesis, new reaction types, crystal structures and spectroscopic characterization of a series of 33 hybrid Mo(W)-Group 12, 14, 15 metal clusters are summarized. These crystals can be put into three categories, i.e. the single cubane type which contains a [M3YS3M'] core (M = Mo, W; Y = 0, S; M'= Sn, Pb, Sb, Bi) (SC type), the double cubane clusters coupled by two bridging oxygen atoms possessing a [Mo3OS3M' (mu -O)](2) core (M'= Pb, Bi) (DC type) and the ionic clusters (IO type) which consists of a {Mo-3} cluster cation and a M' complex anion (M' = Cd, Hg). It is shown that the incorporation of the main group metal M' is through M'-S bonding between M' and three (V-S) atoms of the [M3YS3] cluster core, similar to the case when M' is a transition metal atom. The bonding is however comparatively looser than in the case of a transition metal. The synthetic reactions and structural features of these clusters are discussed. Furthermore, information on the third-order nonlinear optical property observed in some of these compounds is reported. (C) 2001 Elsevier Science Ltd. All rights reserved.