Higher Nuclearity Clusters Containing Osmium and Tin Atoms. Synthesis and Structure of [(OC)3Os(SnMe2)]3, Os4(SnMe2)4(CO)14, and Os4(μ3-O)2(SnMe2)4(CO)14
journal contributionposted on 19.03.1996, 00:00 by Weng Kee Leong, Frederick W. B. Einstein, Roland K. Pomeroy
Pyrolysis of [(OC)4Os(SnMe2)]2 (1) at 170 °C gave [(OC)3Os(SnMe2)]3 (2) as the major product. The structure of 2 reveals a planar triangulated (raftlike) Os3Sn3 unit (6̄ crystallographic symmetry, with Os−Os = 2.974(1) Å and Os−Sn = 2.667(1) and 2.673(1) Å). UV irradiation of 1 in hexane provided the yellow, insoluble Os4(SnMe2)4(CO)14(3). The structure of 3 shows an essentially planar Os4Sn4 skeleton comprised of a central rhomboidal Os2Sn2 unit with each Os atom part of two outer Os2Sn triangles. The Os−Sn bonds of the Os2Sn2 unit at 2.760(1) and 2.780(1) Å are significantly longer than the corresponding bonds of the Os2Sn groups (2.678(1) and 2.727(1) Å); the Os−Os bonds in 3 are long at 3.0414(5) Å. From the treatment of 1 in solution with Me3NO, Os4(μ3-O)2(SnMe2)4(CO)14 (4) was isolated in low yield. The structure of 4 has a central six-membered (OsOSn)2 ring to which are fused two OsOSnOs rings such that each outer ring shares a common OsO edge with the central ring. The outer rings of 4 are planar, but the central ring has a boat conformation.