SYNTHESIS AND STRUCTURES OF 3 EDGE-SHARING BIOCTAHEDRAL COMPOUNDS OF (VI)A METALS CONTAINING FORMAMIDINATO LIGANDS

The direct oxidation of Mo-2(DTolF)(4) with PhICl(2) in CH2Cl2 and cry stallization from toluene resulted in the isolation of the edge-sharin g dimolybdenum(III,IV) compound Mo-2(DTolF)(4)Cl-3 . C7H8 . C6H14 (1), containing two DTolF(-) ligands that are bridging, one that is chelat ing and one that bridges the metal centers in a monodentate fashion. T he oxidation of Cr-2(DTolF)(4) by the same method yielded the symmetri cal dichromium(III,III) compound Cr-2(DTolF)(4)Cl-2 . 3C(6)H(6) (2), c ontaining two bridging and two chelating DTolF(-) ligands. Refluxing M oCl3(THF)(3) and HDPhF with PPh(4)Cl in o-dichlorobenzene followed by crystallization from CH2Cl2 yielded [PPh(4)][Mo-2(DPhF)(2)(NPh)Cl-5]. 2CH(2)Cl(2) (3), in which the bridging imido NPh(2-) group is thought to have resulted from the cleavage of formamidine molecules. The struc tures of these compounds have been determined by X-ray crystallography and their crystallographic data are as follows: 1, monoclinic P2(1)/n with a=14.384(2), b=20.913(2), c=23.601(1) Angstrom, beta=102.498(6)d egrees, V=6931 (1) Angstrom(3), Z=4, R=0.049, wR2=0.121; 2, triclinic P ($) over bar 1 with a=10.128(4), b=11.817(4), c=14.859(7) Angstrom, alpha=103.51(4), beta=95.80(4), gamma=95.30(4)degrees, V=1707(1) Angst rom(3), Z=1, R=0.067, R(w)=0.084; 3, triclinic P ($) over bar 1 with a =15.268(8), b=20.024(2), c=10.401(1) Angstrom, alpha=90.36(1), beta=97 .80(2), gamma=69.92(2)degrees, V=2956(2) Angstrom(3), Z=2, R=0.043, wR 2=0.105.