Abstract
Sodium diselenide reacts with 1,4,5,8-tetrachloronaphthalene (2) in N.iV-dimethylformamide to give 1,8:4,5-bis(diseleno)naphthalene (tetraselenonaphthalene, TSeN, 1) and l,8-diseleno-4,5-dichloronaphthalene (3) as minor and major products, respectively. Purification via gradient sublimation of crude TSeN leads to a black solid whose properties are not in accord with a previous report. Cyclic voltammetry of TSeN in benzonitrile solution reveals reversible one-electron transfers at +0.15 and +0.54 V vs. the Ag/Ag+ reference. The electron spin resonance of TSeN+, generated in dichloromethane solution with trifluoroacetic acid, exhibits a single line 10.4 G wide with g = 2.0431. Grown from chlorobenzene solution, TSeN is a monoclinic crystal of space group P’2,l/c with a = 7.722 (2) Á, b = 4.226 (1) Á, c = 15.305 (4) Á, ß = 102.15 (3)°, V = 488.3 A3, and Z = 2. The structure, solved by Patterson and difference-Fourier syntheses, involves linear chains of TSeN molecules stacked along b with interstack Se-"Se contacts at 3.626 and 3.534 A.