Ligand tetrahedral cluster complexes with

Fig. 8.8. Structures of some carbonyl complexes with M-M bonds, showing (a) a simple unbridged single bond, (b) a tetrahedral M4 cluster with both terminal and bridging CO ligands, (c) a square planar M4 cluster with two GeCH3 groups completing an octahedron, (d) a trigonal-bipyramidal M5 cluster with no bridging CO ligands and (e) a square pyramidal Ms cluster with a carbon atom at the centre of the basal plane.

Another class of chiral tetranuclear complexes are tetrahedral metal-ligand assembled clusters of M4L6 stoichiometry for Ga(III), A1(III), and Fe(III) with A,/V -bis(2,3-dihydroxybenzoyl)-1,5-diamino-naphthalene. This ligand acts as a... 

Geometrically, the main group element tends to retain a tetrahedral nearest neighbor environment, whereas the transition metal element tends to retain an octahedral environment. As a consequence, transition metal clusters with more than six metal atoms have a tendency toward ligand loss, leading to the formation of condensed clusters (multiple interstitial metal atoms). This leads eventually to close-packed structures that mimic bulk metal structures (see Polynuclear Organometallic Cluster Complexes). On the... 

The NacNac ligand, N(Dipp)C(Me)CHC(Me)N(Dipp), has been extensively employed as an ancillary ligand in f-element chemistry and this area has been reviewed elsewhere [78,79]. Recently, the NacNac ligand has been used to stabilize an approximately tetrahedral Yb(II) cluster complex [ Yb(NacNac)(THF) 2 p-Yb(Fp) ] (36 Fp = [Fe(Cp)(CO)2] ), unusually exhibits four Fe—Yb bonds to the same Yb(II) center. Compound 36 was initially isolated as a minor product from the decomposition of [Yb(NacNac)(I)(THF)(p-Fp)]2 in a non-coordinating solvent, however it was found that 36 could be rationally synthesized by the 2 1 reaction of [Yb(NacNac)(I)(THF)(p-Fp)l2 with [Yb(Fp)2(THF)3l2 [80] (Scheme 23). 

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