FORMATION OF SPIROCYCLIC IMIDOPHOSPHINATO COMPLEXES CRYSTAL-STRUCTURES OF [V(OPPH2NPPH2O)2O] AND [MO(NPPH2NPPH2O)2CL2]

Treatment of tetrahydrofuran (thf) solutions of [activated V(NPPh2NPPh2N)Cl2] 1b with Bu(t)OH, LiOBu(t) or NaOSiPh3 affords in small yields the spirocyclic vanadyl complex [activated V(OPPh2NPPh2O)2O] 2. This complex is formed in nearly quantitative yield from [VOCl2(thf)2] and Na[OPPh2NPPh2O]. It crystallizes in the monoclinic space group P2(1)/c with a = 1572.0(8), b = 1056.3(5), c = 2685.0(13) pm, beta = 94.30(2)-degrees and Z = 4. The structure was refined to R = 0.033, R' = 0.044. The nitrogen atoms in 1b adjacent to the metal have been replaced by oxygen atoms during alcoholysis. The V atom has a square-pyramidal geometry. The d1 electronic state was confirmed by ESR measurements. Reaction of MoOCl4 and [H2NPPh2NPPh2NH2]Cl yields the already known [activated Mo(NPPh2NPPh2N)Cl3] 1a and the spirocyclic molybdenum compound [activated Mo(NPPh2NPPh2O)2Cl2] 3. The 1:1 MeCN adduct of 3 crystallizes in the acentric space group P1 with a = 1087.1(5), b = 1156.4(6), c = 1166.5(6) pm, alpha = 82.86(2), beta = 68.26(2), gamma = 64.15(2)-degrees and Z = 1. The Mo atom has a distorted-octahedral geometry with short Mo-N bond lengths (average 177.8 pm).