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). 4H(2)O followed by slow evaporation produces [Cd(NO3)(2)(15-crown-5)] o r [Cd(NO3)(2)(18-crown-6)]. Crystals of [Cd(NO3)(2)(15-crown-5)] are orthor hombic with space group Pbca and cell parameters a = 13.562(5), b = 15.941( 9), and c = 15.011(7) Angstrom at 295 K. [Cd(NO3)(2)(18-crown-6)] crystalli zes in the monoclinic space group C2/c with a = 11.235(2), b = 11.196(5), c = 15.385(3) Angstrom, and beta = 99.89(2)degrees at 295 K. The metal cente r in [Cd(NO3)(2)(15-crown-5)] rests atop the macrocyclic donor array with t wo cis-bound nitrate anions and adopts a distorted tricapped trigonal prism atic geometry. [Cd(NO3)(2)(18-crown-6)] resides on an equatorial twofold ro tation axis with Cd2+ coordinated in the 18-crown-6 cavity and the nitrate anions oriented in twisted trans positions.