REDOX REACTIONS OF LOW-VALENT GROUP-4 ORGANOMETALLICS WITH 9,10-PHENANTHRENEQUINONE (PQ) - CRYSTAL AND MOLECULAR-STRUCTURE OF A 10-MEMBEREDTETRAOXAMETALLACYCLE OF BIS(CYCLOPENTADIENYL)ZIRCONIUM(IV)

The bis(arene) derivative of titanium(0), Ti(eta(6)-toluene)(2), react s with 9,10-phenanthrenequinone (PQ) with release of the arene ligands and formation of a diamagnetic brown compound best formulated as a di nuclear titanium(IV) derivative containing both 9,10-phenanthrenesemiq uinone (PSQ) and 9,10-phenanthrenediolato (PDA) ligands. MCp2(CO)(2) ( M = Zr, Hf) react with PQ to give MCp(2)PDA which has been characteriz ed by single crystal X-ray diffractometry for M = Zr. Crystal data: C4 8H36O4Zr2, M = 859.26 g mol(-1), monoclinic, space group P2(1)/n (No. 14), a = 11.647(8), b = 17.07(1), c = 18.80(1)Angstrom, beta = 97.17(6 )degrees, V = 3709(7)Angstrom 3, Z = 4, d(calc) = 1.539 g cm(-3), mu = 5.97 cm(-1), F(000) = 1744. The structure consists of dinuclear [ZrCp (2)PDA](2) units, the two ZrCp2 groups being bridged by the PDA ligand s to give a 10-membered tetraoxazirconacycle. (C) 1997 Elsevier Scienc e S.A.