Homoleptic dithiolenes tris complexes

Homoleptic dithiolene complexes such as ML , where L = dithiolene ligand (1,1-, 1,2- or 1,3-), and n = 2 [bis(dithiolene)] or 3 [tris(dithio-lene)] (see Scheme 2). Within this class of compounds, a further distinction should be made between symmetrical compounds in which all dithiolene ligands are identical [see, e.g., M(mnt)2 in Scheme 3 ... 

A. Transition Metal Homoleptic Tris(dithiolene) Complexes / 80... 

There are roughly 50 homoleptic tris (dithiolene) complexes reported in the CSDC (5). The elemental distribution of these structures is outlined in Fig. 15. As opposed to bis(dithiolene) complexes, tris(dithiolene) complexes are based predominantly on early transition metal elements. Many of the tris(dithiolene) complexes are centered on V, Mo, and W. There are also complexes of Ti, Zr, Nb, Ta, Cr, Tc, Re, Ru, and Os. In addition, there are tris(dithiolene) complexes of Fe and Co, elements that also form homoleptic complexes with two dithiolene ligands. A detailed listing of the structural units along with references and geometrical parameters (to be discussed) is given in Table IV. 

Figure 15. Distribution and frequency of homoleptic tris(dithiolene) complexes.

Average bond length and angle parameters for the homoleptic tris(dithiolene) complexes are less sensitive to the identity of the transition metal or dithiolene ligand than those of bis(dithiolene) structures. Ranges of values are summarized in Fig. 22. Average M—S bond lengths cluster between 2.263 and 2.543 A, with values for two [Fe(mnt)3]2 units (2.263 and 2.269 A) (18), Co CAlCO),, 3... 

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