Structure studies molybdenum arenes

The reaction of [MoBr2(CO)4] with the DPT anion (DPT = 2,6-di-phenylthiophenolate) differs from that with other 2,6-substituted aromatic thiolates. The stoichiometry [Mo(DTP)2(CO)] of the product initially suggested three coordination however, spectroscopic studies and an X-ray crystal structure revealed that one of the 2,6-phenyl groups is 7j -bonded to the molybdenum (Fig. 6). The 7j -arene ligand is labile and can be reversibly replaced by three CO ligands. Replacement of this ligand also occurs with 2,2 -bipyridyl (bipy), 1,10-phenanthroline... 

T -Arene complexes containing late metals have been known for many years, but the scope and utility of these complexes have increased in recent years. Copper(I) and silver form labile arene complexes of various stoichiometries that are apparently T -arene complexes. A few of these complexes have been structurally characterized. More recently, a large number of V-arene and heteroarene complexes of osmium, rhenium, molybdenum, and tungsten have been prepared for the purpose of dearomatization of the arene or heteroarenes. Two examples are shown in Figure 2.33. This dearomatization creates a diene or vinyl unit that imdergoes the organic chemistry of ttiese isolated units, instead of the chemistry of an arene. n -Arene complexes of rhodium and platinum have been characterized structurally and studied in the context of their likely intermediacy in the oxidative addition of arene C-H bonds. ... 

Chromium, Molybdenum and Tungsten The intramolecular rotational behaviour of a series of highly substituted Ti -arene chromium and molybdenum compounds has been examined in detail. Dynamic processes in the solid state, using spin-lattice relaxation time measurements, have been studied for two structurally characterised polymethyl benzenechromium tricarbonyl complexes. The mechanism of migration of the Cr(CO)3 unit from the six to the five membered ring in indenyl anions has been reported. The synthesis and cyclic voltammetry of (Ti -phenylmethylsila-14-crown-5)chromiumtricarbonyl has appeared. ... 

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