The structures of
Ni(C≡CR)(PPh3)(η-C5H5)
(R = Ph (1),
C6H4-4-NO2
(2),
4-C6H4C6H4-4′-NO2
(3),
(E)-4-C6H4CH=CHC6H4-4′-NO2
(4),
4-C6H4C≡CC6H4-4′-NO2
(5),
4-C6H4N=CHC6H4-4′-NO2
(6)) have been determined by single-crystal X-ray diffraction studies,
refining by full-matrix least-squares analysis. For (1), crystals are
triclinic, space group
P-1, with
a 10·094(2),
b13·429(3), c
18·835(5) Å,α 103·24(2), β 91·50(2),
γ 90·10(2)°, Z 4, 5844 unique reflections
(595 parameters), converging at R 0·033 and
Rw 0·024. For (2), crystals
are orthorhombic, space group
Pna21, with
a 16·799(2), b
8·681(2), c 17·485(2) Å,
Z 4, 1774 unique reflections (325 parameters),
converging at R 0·031 and
Rw 0·029. For (3), crystals
are monoclinic, space group P
21/c, with
a 11·140(3), b
18·282(4), c 15·296(2) Å, β
105·18(2)°, Z 4, 3132 unique reflections
(397 parameters), converging at R 0·039 and
Rw 0·024. For (4), crystals
are monoclinic, space group P
21/n, with
a 12·929(7), b
16·953(8), c 15·601(7) Å, β
112·55(3), Z 4, 3023 unique reflections (397
parameters), converging at R 0·039 and
Rw 0·025. For (5), crystals
are monoclinic, space group P
21/n, with
a 12·710(5), b
16·882(3), c 15·693(4) Å, β
111·37(3)°, Z 4, 3216 unique reflections (397
parameters), converging at R 0·035 and
Rw 0·030. For (6), crystals
are monoclinic, space group P
21/n, with
a 12·594(1), b
16·936(2), c 15·611(1) Å, β
112·476(5)°, Z 4, 3564 unique reflections
(397 parameters), converging at R 0·038 and
Rw 0·041. For structurally
characterized 18-electron (cyclopentadienyl)nickel(II) acetylide complexes,
statistically insignificant decreases in the average Ni-C(1) distance and
trans influence and an increase in the average C(1)-C(2) parameter are
observed on introduction of an acceptor substituent at the alkynyl ligand.
