Synthesis and Molecular and Extended Structures for a Diaminonaphthalene-Derived Bis(amido)stannylene

The cyclic bis(amido)tin(II) compound Sn[1,8-(iPrN)2C10H6] (2) was isolated from the reaction of Li2[1,8-(iPrN)2C10H6] (1) and SnCl2. Solid-state structural analysis of 2 showed it to be a mononuclear species with a pyramidal Sn center as part of a nonplanar metallaheterocycle. The packing diagram of 2 revealed an extended one-dimensional head-to-tail chain structure with short intermolecular Sn/arene-C interactions. Computational examination of 2 (DFT/PW91 and MP2 with 6-31G* and 6-311G** basis functions) indicated that the optimum gas-phase structure of 2, which displays a Sn center in the plane of the naphthyl backbone with a slightly twisted metallaheterocycle, is approximately 24 kcal/mol lower in energy than the X-ray structure. The solid-state geometry of 2 is attributed to the intermolecular donation of the naphthalene (pi)-electrons to a Lewis acidic Sn center, which leads to the observed supramolecular structure. The crystal structure of 1 is also reported.