Mechanistic diversity covering 15 orders of magnitude in rates: cyanide exchange on [M(CN)(4)](2-) (M = Ni, Pd, and Pt).

Kinetic studies of cyanide exchange on [M(CN)(4)](2-) square-planar complexes (M = Pt, Pd, and Ni) were performed as a function of pH by (13)C NMR. The [Pt(CN)(4)](2-) complex has a purely second-order rate law, with CN(-) as acting as the nucleophile, with the following kinetic parameters: (k(2)(Pt,CN))(298) = 11 +/- 1 s(-1) mol(-1) kg, DeltaH(2) (Pt,CN) = 25.1 +/- 1 kJ mol(-1), DeltaS(2) (Pt,CN) = -142 +/- 4 J mol(-1) K(-1), and DeltaV(2) (Pt,CN) = -27 +/- 2 cm(3) mol(-1).

13C and (15)N NMR Mechanistic Study of Cyanide Exchange on Oxotetracyanometalate Complexes of Re(V), Tc(V), W(IV), Mo(IV), and Os(VI).

A range of complexes with general formula [MO(X)(CN)(4)](n)()(-) of W(IV), Mo(IV), Re(V), Tc(V), and Os(VI) were prepared and characterized by (13)C, (15)N, (17)O, and (99)Tc NMR, utilizing (13)C- and (15)N-enriched cyano complexes. A correlation between M-O and M-CN bond strength from X-ray crystallographic data and |(1)J((183)W-(13)C)| coupling is reported. The cyanide (HCN/CN(-)) exchange kinetics on the trans-dioxotetracyanometalate complexes and protonated/substituted ([MO(X)(CN)(4)](n)()(-)) forms thereof were studied in aqueous medium.