Electron-and Ligand-Transfer Reactions Involving N,N-Dialkylcarbamates. Synthesis and Molecular Structure of V 2 [η 5 -(C 5 H 5 )] 2 [O 2 CN(C 2 H 5 ) 2 ] 4

Electron-and ligand-transfer reactions of low-valent organometallic compounds of titanium and vanadium with N,N-dialkylcarbamates of titanium(IV) are reported. The reaction of VCp 2 (Cp = η 5 -cyclopentadienyl) with Ti(O 2 CNEt 2 ) 4 affords, inter alia, the dimeric vanadium(III) N ,N-diethylcarbamato derivative V 2 Cp 2 (O 2 CNEt 2 ) 4 which has been studied by X-ray diffraction methods. Crystal data; triclinic, space group P1̄ ; a = 10.802(2), b = 11.004(1), c = 8.960(1) Å; α = 112.879(9), β = 102.66(1), γ = 102.42(1)°; V = 902.3(6) Å 3 ; Z = 1; F(000) = 368, ρ calc = 1.282 g cm -3 ; μ = 5.47 cm -1 . It consists of a centrosymmetric dimer, the two vanadium atoms being surrounded by four oxygen atoms of the bridging N,N-diethylcar-bamato groups and by the cyclopentadienyl ligand. The metal atom exhibits a distorted square-pyramidal coordination geometry with the oxygen atoms occupying the basal plane. The reaction of TiCp 2 (CO) 2 or Vmes 2 (mes = η 6 -1,3 ,5 -Me 3 C 6 H 3 ) with Ti(O 2 CNEt 2 ) 4 affords Ti(III) and V(III) N,N-diethylcarbamato derivatives by a simultaneous ligand-and electron-transfer reaction. Magnesium N ,N-diisopropylcarbamate, Mg(O 2 CNPr i 2 ) 2 , has been obtained by a ligand-transfer reaction between MgCp 2 and Ti(O 2 CNPr i 2 ) 3 .