The homoleptic [M(MeCN)(4)](2+) cations (M = Pd, Pt) as the tetrafluoroborato derivatives were reacted with NHEt(2). The platinum species affords the amidino derivative {Pt[(E)-HN=C(NEt(2))Me](4)}[BF(4)](2), 1, as the only detected product of the addition of the amine to the coordinated nitrile. On the contrary, for [Pd(MeCN)(4)][BF(4)](2) competition between the substitution of the nitrile and addition of the amine to the nitrile group is operative: by carrying out the reaction in acetonitrile as solvent, complete conversion was obtained to the crystallographically defined {Pd[(E)-HN=C(NEt(2))Me](4)}[BF(4)](2). Consistent with these findings, PdCl(2)(MeCN)(2) reacts with NHEt(2) in acetonitrile yielding the substitution complex PdCl(2)(NHEt(2))(2), whereas the amidino complex cis-PtCl(2)[(E)-HN=C(NEt(2))Me](2), 3 was obtained from PtCl(2)(MeCN)(2). Complex 3 was characterized by X-ray diffractometry. (C) 2010 Elsevier B.V. All rights reserved.