| Abstrakt: |
The structures of Au(4-C≡CC6H4XYC6H4-4′-NO2)(PPh3) (XY= (E)-CH=CH (1), (Z)-CH=CH (2), C≡C (3), N=CH (4)) have been determined by single-crystal X-ray diffraction analyses, refining by full-matrix least-squares analysis. For (1), crystals are triclinic, space group P-1, with a8·847(1), b17·870(4), c19·705(3) Å, α116·25(1), β 93·33(1), γ 92·64(2)˚, Z4, 6747 unique reflections (703 parameters), converging at R0·025 and Rw0·029. For (2), crystals are monoclinic, space group P21/a, with a10·718(6), b19·398(5), c14·469(3) Å, β 108·96(2)˚, Z4, 3295 unique reflections (352 parameters), converging atR0·040 and Rw0·034. For (3), crystals are triclinic, space group P-1, with a10·671(4), b17·599(7), c18·220(8) Å, α 116·31(3), β 105·00(4), γ 95·08(4)˚, Z4, 4828 unique reflections (703 parameters), converging at R0·043 and Rw0·030. For (4), crystals are triclinic, space group P-1, with a8·8314(6), b17·834(2), c20·001(2) Å, α 115·249(7), β 90·930(7), γ 94·082(7)˚, Z4, 4724 unique reflections (703 parameters), converging at R0·035 and Rw0·034. Despite the [ligated metal donor]-bridge-[nitro acceptor] composition of these complexes, Au–C and C≡C distances are normal and consistent with minimal allenylidene contribution to the ground-state geometry. Within the 3σ confidence limits, the structural data do not provide evidence for π*-back-bonding in these complexes |
