Reactions of ethyl cyanoformate with (np3)Ni, (np3)CoH [np3 = N(CH2CH2PPh2)3], and (triphos)Ni [triphos = MeC(CH2PPh2)3]. Crystal structures of the ethoxycarbonyl complexes [(np3)Ni(CO2Et)]BPh4 and (triphos)Ni(CN)(CO2Et)

Article abstract of DOI:10.1021/om00139a026

Ethyl cyanoformate, NCCO₂Et, is used as starting material to introduce ethoxycarbonyl and/or cyanide groups into complex frameworks. Thus, NCOO₂Et reacts with the Ni(0) complex (np₃)Ni (1) [np₃ = N(CH₂CH₂PPh₂)₃] or with the Ni(0) fragment (triphos)Ni [triphos = MeC(CH₂PPh₂)₃] to give [(np₃)-Ni(CO₂Et)]⁺ (3) and (triphos)Ni(CN)(CO₂Et) (4), respectively. The crystal structures of 3·BPh₄ and 4 have been determined by standard X-ray methods. Compound 3·BPh₄ crystallizes in the monoclinic space group C2/c with a = 33.429 (10) A?, b = 8.929 (2) A?, c = 38.773 (11) A?, β = 100.25 (2)°, and Z = 8. The structure was refined to an R factor of 0.068 (R_w = 0.068) by using 2908 reflections with I > 3σ(I). The coordination polyhedron of the nickel(II) atom can be described as a trigonal bipyramid whose equatorial plane is defined by the three phosphorus atoms of np₃. Compound 4 crystallizes in the orthorhombic space group Pn2₁a with a = 26.957 (8) A?, b = 13.480 (4) A?, c = 10.690 (3) A?, and Z = 4. The structure was refined to an R factor of 0.055 (R_w = 0.056) by using 1897 reflections with I > 3σ(I). The compound exhibits quite regular square-pyramidal environment of the nickel(II) atom. Reaction of NCCO₂Et with the Co(I) hydride (np₃)CoH (5) yields (np₃)Co(CN) and HCO₂Et.