Cyanoisocyanoarene metal complexes as building blocks for coordination polymers: Structural nonrigidity of a metal-nitrile linkage

The complexes trans-[PdI2(CNR)(2)], 1a-1e, (CNR = 3-CN-C6H4-CN (1a), 4-CN-3-C2H5-C6H3-CN (1b), c: 4-CN-3-Cl-C6H3-CN (1c), 4-CN-1,2-(NC)(2)-C6H3 (1d), 4-CN-C6H3-CH2CN (1e)), have been prepared. Complex 2a forms a coordination polymer, 3, with copperbis(hexafluoroacetylacetonate) in the ratio of 1:2. The crystal structures of compounds 2b, 2c, 2e, and 3 have been determined by X-ray crystallography. 2b: C20H16I2N4-Pd, monoclinic space group, P1 (no. 2), a = 4.630(2) Angstrom, b = 8.365(4) Angstrom, c = 14.835(5) Angstrom, beta = 98.03(2)degrees, Z = 1 1964 unique reflections, R = 0.038, R-w = 0.036. 2c: C16H6C12I2N4Pd, monoclinic space group, P1 (no. 2), a = 7.569(1) Angstrom, b = 8.229(1) Angstrom, c = 9.114(2) Angstrom, beta = 77.21(1)degrees, Z = 1, 1633 unique reflections, R = 0.030, R-w = 0.028. 2e: C18H12I2N4Pd, monoclinic space group, C2/c (no. 15), a = 14.171(3) Angstrom, b = 8.3781(7) Angstrom, c = 18.096(4) Angstrom, beta =103.41(1)degrees, Z = 4, 2198 unique reflections, R = 0.036, Rw = 0.023. 3: C36H12Cu2F24I2N4O8Pd, monoclinic space group, P1 (no. 2), a = 10.946(2) Angstrom, b = 11.315(3) Angstrom, c = 12.261(3) Angstrom, beta = 99.39(1)degrees, Z = 1, 2698 unique reflections, R = 0.049, R-w = 0.057.