Synthese und Struktur bicyclischer arsenhaltiger Schwefel-Stickstoff-Metallkomplexe / Synthesis and Structure of Bicyclic Sulphur Nitrogen Metal Complexes Containing Arsenic

(PhAsNSN)2 (1) reacts with M(CO) 4 (C 7 H 8 ) (M = a Cr. b Mo) to yield (PhAsNSN) 2 M(CO) 4 (2). 2a and 2b are dark red air stable complexes. 2b was characterized by X-ray diffraction. Crystals of 2b are monoclinic, space group C2/c, with a = 2884.7(4). b = 1166.2(2), c = 1344.1(2) pm, fβ = 104.81(2)° and Z = 8. The molecule exhibits approximate mm (C 2v ) symmetry with mean bond lengths: Mo-As 255.1. Mo-C 201.8. As-N 186.2 and S -N 152.8 pm.