Synthesis, Crystal Structure, Magnetic Susceptibility, and Single-Crystal EPR Studies of [DafoneH < inf > 2 < /inf > ][(CuCl < inf > 3 < /inf > H < inf > 2 < /inf > O)Cl]

Abstract

[DafoneH2][(CuCl3H2O)]Cl (dafone = 4,5-diazafluoren-9-one) crystallizes in the monoclinic space group P21/c with a = 14.585(2) Å,b = 14.143(7) Å, c = 7.076(6), Å, β = 91.3(2)°, and Z = 4. The crystal contains the unusual chromophore [(CuCl3H2O)Cl]2- showing coordinated water and a semicoordinate Cl-. Moderately strong antiferromagnetic exchange (J = −72.8 K, with Hex = −2JŜ1Ŝ2) is present. The exchange pathway appears to be via an H-bond involving H2O and Cl- of inversion-related molecules. Cl···Cl contacts also exist, but on the basis of geometry, EHMO calculations, and comparison with other systems, they are ruled out as the main exchange pathway. Single-crystal EPR studies (g1 = 2.069, g2 = 2.089, g3 = 2.250) show further weak exchange via H-bonding between the semicoordinate Cl- and H2O. © 1994, American Chemical Society. All rights reserved.