Cadmium cyanide–ether clathrates: crystal structures of Cd8(CN)16(H2O)6·6G (G = Et2O or Pri2O) and Cd3(CN)6(H2O)2·2Prn2O

Abstract

The cadmium cyanide host clathrates Cd₈(CN)₁₆(H₂O)₆·6G (G = Et₂O 1a or Prⁱ₂O 1b) and Cd₃(CN)₆(H₂O)₂·2Prⁿ₂O 2 have been prepared and their structures determined by X-ray crystallography: 1a, cubic, space group P3n, a= 15.661 (5)Å, Z= 2, R= 0.045 for 565 reflections; 1b, cubic, space group P3n, a= 15.762(9)Å, Z= 2, R= 0.035 for 653; 2, monoclinic, space group C2/c, a= 14.044(6), b= 18.034(6), c= 12.931 (4)Å, β= 111.47(2)°, Z= 4, R= 0.040 for 2003. The novel hosts in 1a and 1b contain tetrahedral and octahedral Cd atoms in a 5:3 ratio. The host in 2 is isostructural to that of the previously reported Cd₃(CN)₆(H₂O)₂·2PrⁱOH 3, containing tetrahedral and octahedral cadmium atoms in a ratio of 2:1. The guest ether molecules are accommodated in cage-like cavities, and participate in hydrogen bonding between their O atoms and those of the co-ordinated water molecules.