Reactions of [Y(BDI)(I)2(THF)] [BDI = {HC(CMeNAr)2}−, Ar = 2,6-diisopropylphenyl] with Na[M(Cp)(CO)3] (M = Cr, W): X-ray crystal structures of [{Y(BDI)[Cr(Cp)(CO)3]2(THF)}2] and [W(Cp)(CO)3][Na(THF)2]

Reaction of [Y(BDI)(I)2(THF)] (1) with two equivalents of Na[Cr(Cp)(CO)3] affords the dimeric complex [{Y(BDI)[Cr(Cp)(CO)3]2(THF)}2] (2). Complex 2 contains two yttrium-BDI units which are each linked by two isocarbonyl bridging [Cr(Cp)(CO)3]− anions; a terminal, isocarbonyl bound [Cr(Cp)(CO)3]− anion and THF molecule completes the coordination sphere at each yttrium. This results in formation of a centrosymmetric, 12-membered C4O4Cr2Y2 ring. Forcing conditions were required to produce carbonyl metallate derivatives such as 2, as exemplified by the isolation of crystals of [W(Cp)(CO)3][Na(THF)2] (3) from the analogous reaction between 1 and two equivalents of Na[W(Cp)(CO)3]. Complex 3 loses coordinated THF very easily and all isolated samples exhibit spectra consistent with the known, un-solvated form of Na[W(Cp)(CO)3]. The crystal structure of 3 shows dimeric sodium units bridged by two THF molecules and one isocarbonyl group. Each sodium centre is further coordinated by one THF molecule and two isocarbonyl ligands. There are two crystallographically distinct [W(Cp)(CO)3]− units; one exhibits two bridging isocarbonyl groups and the other exhibits three bridging isocarbonyl groups to different sodium dimer units. This results in a 2-dimensional polymeric sheet network in the solid state. Complex 2 was characterised by single crystal X-ray diffraction, NMR spectroscopy, FTIR spectroscopy and CHN microanalysis; complex 3 was characterised by single crystal X-ray diffraction only.