Formation of spirocyclic imidophosphinato complexes: crystal structures of [V(OPPh2NPPh2O)2O] and [Mo(NPPh2NPPh2O)2Cl2]

Abstract

Treatment of tetrahydrofuran (thf) solutions of [[graphic omitted])Cl₂]1b with Bu^tOH, LiOBu^t or NaOSiPh₃ affords in small yields the spirocyclic vanadyl complex [[graphic omitted])₂O]2. This complex is formed in nearly quantitative yield from [VOCl₂(thf)₂] and Na[OPPh₂NPPh₂O]. It crystallizes in the monoclinic space group P2₁/c with a= 1572.0(8), b= 1056.3(5), c= 2685.0(13) pm, β= 94.30(2)° 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 The nitrogen atoms in 1b adjacent to the metal have been replaced by oxygen atoms during alcoholysis.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 [[graphic omitted])Cl₃]1a and the spirocyclic molybdenum compound [[graphic omitted])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, α= 82.86(2), β= 68.26(2), γ= 64.15(2)° and Z= 1. The Mo atom has a distorted-octahedral geometry with short Mo–N bond lengths (average 177.8 pm).