Metal Complexes of Pyridylphenylisocyanides and Pyridylethynylphenylisocyanides as Building Blocks for Coordination Polymers and Supramolecular Assemblies

The isocyanides 3-(4-pyridylethynyl)phenylisocyanide, 3, 4-(4-pyridylethynyl)phenylisocyanide, 6, 2,6-diisopropyl-4-(4-pyridylethynyl)phenylisocyanide, 9, and 2,6-diisopropyl-4-(4-pyridyl)phenylisocyanide, 11, were prepared. With PdI₂ and PtI₂, these isocyanides form the complexes trans-[MI₂(CNR)₂], 12−19 (M = Pd, Pt; CNR = 3, 6, 9, 11). The previously prepared complex trans-[PdI₂(CNC₅H₄N-3)₂] and trans-[PdI₂(CNC₆H₂-(i-Pr)₂-2,6-(CC−C₅H₄N-4)-4)₂], 16, combine with copper bis(trifluoroacetylacetonate) in the ratio of 1:2 to form the adducts trans-[PdI₂(CNC₅H₄N-3)₂]·2[Cu(tfacac)₂]·2CH₂Cl₂, 20, and trans-[PdI₂(CNC₆H₂-(i-Pr)₂-2,6-(CC-C₅H₄N-4)-4)₂]·2[Cu(tfacac)₂], 21, respectively. The complexes trans-[MI₂(CNC₆H₂-(i-Pr)₂-2,6-(C₅H₄N-4)-4)₂], 19 (M = Pd) and 20 (M = Pt), react with [Pd(SO₃CF₃)₂(dppp)] (dppp = bisdiphenylphosphinopropane) to form the molecular squares [Pd(dppp)(trans-[MI₂(CNC₆H₂-(i-Pr)₂-2,6-(C₅H₄N-4)-4)₂]₄(SO₃CF₃)₈, 22 (M = Pd) and 23 (M = Pt). The crystal structure of 20 has been determined by X-ray crystallography. 20:  C₃₄H₂₈Cl₄Cu₂F₁₂I₂N₄O₈Pd, monoclinic space group, P2₁/n (No. 14), a = 10.899(3) Å, b = 13.903(1) Å, c = 17.827(6) Å, β = 105.50(2)°, Z = 2, 2618 unique reflections, R = 0.093, R_w = 0.091.