Conformational Polymorphism of Ni(NCS)2 (P(CH2CH2CN)3)2: A Crystallographic Study of Three Polymorphs

摘要

Three conformational polymorphs of Ni(NCS)2(P(CH2CH2CN)3)2 have been synthesized and their crystal structures determined by single-crystal X-ray diffraction techniques. All three crystallize in space group P21/c: cell constants for polymorph 1, a = 13.44(2) A, b = 9.04(1) A, c = 24.45(2) A, and beta = 115.4(1) degrees; polymorph 2, a = 16.153(5) A, b = 12.393(4) A, c = 13.852(4) A, and beta = 107.89(4) degrees; polymorph 3, a = 11.032(3) A, b = 10.335(3) A, c = 11.801(4) A, and beta = 107.21(5) degrees. Full matrix least-squares refinement of positional and thermal parameters led to R = 0.205, R sub W = 0.224; R = 0.070, R sub W =0.107; and R = 0.038, R sub W =0.045 for polymorphs 1, 2, and 3, respectively, with 519, 2499 and 1852 reflections (F greater than 3.92 sigma(F)). All three complexes have the expected square-planar geometry. However, polymorphs 2 and 3 have distinct bonding and packing environments, while the packing and non-bonded interactions of polymorph 1 display features common to both.