An Extremly Bent Cyanide Bridge in Crystals of [(CN)₃Pt(μ-CN)Cu(NH₃)₄]. Influence of Electrostatic Forces on the Nature and Geometry of Bridging Cyanides in the Solid State^†

The dinuclear heterometallic complex [(CN)3Pt(μ-CN)Cu(NH3)4] has been obtained in the solid state, and its structure has been determined by X-ray diffraction techniques at two temperatures (102 and 233 K). C4H12CuN8Pt crystallizes in the orthorhombic system, with a = 14.554(3) Å, b = 7.1901(12) Å, c = 10.369(2) Å, and V = 1085.1(3) Å3 at 102 K (a = 14.5091(10) Å, b = 7.2739(4) Å, c = 10.4570(7) Å, and V = 1103.61(12) Å3 at 233 K), in space group Pnma, with Z = 4. The Pt and Cu atoms are linked by a CN bridge that presents a very bent C⋮N−Cu angle (120.1(6)° at 102 K). The C⋮N and N−Cu distances at 102 K are 1.147(10) and 2.394(7) Å, respectively. [(CN)3Pt(μ-CN)Cu(NH3)4] is embedded in an extensive electrostatic net formed by (N)H···N(C) interactions which, it is concluded, play an important role in the extreme deviation from linearity observed for the C⋮N−Cu angle.