Synthesis and X-ray crystallographic characterization of [Cd(NO3)2(15-Crown-5)] and [Cd(NO3)2(18-Crown-6)]

Reaction of 15-crown-5 or 18-crown-6 in 3:1 (v/v) CH3CN:CH3OH with Cd(NO3)2·4H2O followed by slow evaporation produces [Cd(NO3)2(15-crown-5)] or [Cd(NO3)2(18-crown-6)]. Crystals of [Cd(NO3)2(15-crown-5)] are orthorhombic with space group Pbca and cell parameters a = 13.562(5), b = 15.941(9), and c = 15.011(7) Å at 295 K. [Cd(NO3)2(18-crown-6)] crystallizes in the monoclinic space group C2/c with a = 11.235(2), b = 11.196(5), c = 15.385(3) Å, and β = 99.89(2)° at 295 K. The metal center in [Cd(NO3)2(15-crown-5)] rests atop the macrocyclic donor array with two cis-bound nitrate anions and adopts a distorted tricapped trigonal prismatic geometry. [Cd(NO3)2(18-crown-6)] resides on an equatorial two-fold rotation axis with Cd2+ coordinated in the 18-crown-6 cavity and the nitrate anions oriented in twisted trans positions.