Polymorphism of 1,3-Phenylene Bis(diselenadiazolyl) - Solid-State Structural and Electronic-Properties of Beta-1,3-[(Se2n2c)c6h4(cn2se2)]
by Cordes, A. Wallace; Haddon, Robert C.; Hicks, Robin G.; Oakley, Richard T.; Palstra, Thomas T. M.; Schneemeyer, Lynn F.; Waszczak, Joseph V.
The solid-state characterization of a second or beta-phase of the 1,3-phenylene-bridged diselenadiazolyl diradical 1,3-[(Se2N2C)C6H4(CN2Se2)] is reported. Crystals of this beta-phase are monoclinic, space group P2(1)n, with a = 9.108 (6), b = 15.233 (13), c = 16.110 (5) angstrom, beta = 103.37 (5)-degrees, Z = 8. The crystal structure consists of chain-like arrays of discrete dimers (4 per unit cell), although one intradimer Se-Se linkage is notably longer (3.411 angstrom) than the other three (3.125, 3.196, 3.204 angstrom). The dimer units lie in chains that are linked by a complex three-dimensional array of Se-Se contacts. Variable-temperature single-crystal conductivity measurements on this phase indicate a band gap of 0.77 eV. Consistent with the conductivity measurements, extended Huckel band structure calculations suggest a relatively isotropic electronic structure.
- Journal of the American Chemical Society
- Start Page
- 1520-5126; 0002-7863