Bis(isothiocyanato)bis(phosphine) complexes of group 10 metals: reactivity toward organic isocyanides

Treatment of Ni(NCS)(2)(PMe2Ph)(2) With organic isocyanides CN-R gave five-coordinate isocyanide Ni(II) complexes, Ni(CN-R)(NCS)(2)(PMe2Ph)(2) (R = C6H3-2,6-Me-2 (1), t-Bu (2)). Interestingly, the corresponding reaction of Ni(NCS)(2)(P(n-Pr)(3))(2) with 2 equiv. of CN-t-Bu gave an unusual compound, which exists as an ion pair of the trigonal bipyramidal cation [Ni(P(n-Pr)(3))(2)(CN-t-Bu)(3)](2+) (3) and the dinuclear NCS-bridged anion [Ni(1,3-mu-NCS)(NCS)(3)](2) (2-) (4). In contrast, Pd(NCS)(2)(P(n-Pr)(3))(2) underwent substitution with 2 equiv. of CN-t-Bu to give the four-coordiriate mono(isocyanide) Pd(II) complex Pd(NCS)(SCN)(CN-t-Bu)(P(n-Pr)(3)) (5) t4a phosphine dissociation. Reactions of M(NCS)(2)L-2 (M = Pd, Pt; L = PMe3, PEt3, PMePh2, P(n-Pr)(3)) With two equiv. of CN-R (R = t-Bu, i-Pr, C6H3-2,6-Me-2) gave the corresponding bis(isocyanide) complexes [M(CN-R)(2)(PR3)(2)](SCN)(2) (7-13), except for Pd(NCS)(2)(PEt3)(2) that reacted with CN-R' (R' = i-Pr, C6H3-2,6-Me-2) and produced the rnono(isocyanide) Pd(II) complexes [Pd(CN-R')(SCN)(PEt3)(2)](SCN) (14 and 15). Finally, treatment of M(NCS)(2)(PMe3)(2) (M = Ni, Pd, Pt) with sterically bulky isocyanide CN-C6H3-2,6-i-Pr-2 gave various products, (16-18) depending on the identity of the metal.