O acac

Among the chelated species, octacoordination is often encountered. The tetrakis-acetylacetonate complex of U(IV) (a-form) and Ce(IV) are isostructural. A two-dimensional X-ray analysis showed a slightly distorted square antiprismatic geometry [109—111) for Ce(acac)4 belonging to space group P2i/c [Ctn] with an average Ce—O (acac) bond length of 2.40 A and an <0—Ce—0 of 72°. The a-form of Th(acac)4 is found to be isomorphous (770) with Ce(acac)4 (Th—0=2.41 A)... 

Ir(III) complexes can also be used to catalyze the hydroarylation of olefins [5, 6], The catalyst precursors (acac-0,0)2Ir(Ph)(L) (L= pyridine or H20) and [Ir(w-acac-0,0,C3)(acac-0,0)(acac-C3)]2 have been reported and are depicted in Scheme 3, with representative catalytic reactions. Among these catalyst precursors, (acac-0,0)2Ir(Ph)(H20) has been demonstrated to be the most active system [5], The lin-ear-to-branched ratios observed for Ir(III) catalyzed reactions of a-olefins are remarkably similar to those obtained using TpRu(CO)(NCMe)(Ph). For example, hydrophenylation of propene using 11 r (a-acac- O, O,C ) (acac-O, O) (acac-C3) ]2 as catalyst produces a 1.6 1 ratio of linear propylbenzene to cumene (identical to the ratio observed using the Ru(II) catalyst). Similar to the TpRu(CO)(NCMe)(R) catalysts, the regioselectivity of hydroarylation of ethylene that incorporates monoalkyl arenes produces meta- and para-disubstituted alkyl arenes in approximately 2 1 ratio without observation of ortho-disubstituted products. 

Pd(acac)2(PPh3)] 0.078 square-planar Pd with co-ordination via P. two O (acac bidentate), and y-C (acac unidentate) h... 

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