A NEW SYNTHETIC ROUTE TO SE2NCL3 LEADING TO A NEW MODIFICATION OF THIS CHLORIDE NITRIDE OF TRIVALENT SELENIUM

Se2NCl3 was prepared in 58% yield by the reaction of SeCl4 with Se-2[N (SiMe(3))(2)](2). This method provides a new and convenient one-day an d one-pot synthesis for the preparation of this neutral chloronitride of trivalent selenium. The low-temperature structure was determined by a single-crystal X-ray diffraction analysis. The compound crystallize s in the monoclinic space group P2(1)/a with Z = 4 and unit cell dimen sions a = 7.605(3), b = 8.7643(20), c = 8.966(3) Angstrom, and beta = 93.23(3)degrees. The structure is made up of essentially planar Se2NCl 3 molecules (C-2v symmetry) that are packed in a coplanar fashion to f orm one-dimensional chains. There are strong intermolecular interactio ns with short intermolecular Se...Se distances of 3.82 Angstrom, which is significantly shorter than the sum of the covalent radii (4.0 Angs trom). This explains the golden color and the metallic luster of this compound. Se2NCl3 was first reported in 1992 by K. Dehnicke et al. to form transparent red crystals (orthorhombic, space group P bca, a = 12 .290(6), b = 8.046(4), c = 24.336(12) Angstrom) without significant in termolecular interactions (Se...Se, 4.10 Angstrom). Therefore, Se2NCl3 is polymorphic, crystallizing either in the orthorhombic or in the mo noclinic system. (C) 1996 John Wiley & Sons, Inc.