Osmium−Germanium Clusters. Structures of [(OC)₄Os(GeMe₂)]₂, Os₂(GeMe₂)₃(CO)₆, Os₃(GeMe₂)₂(CO)₁₁, [(OC)₃Os(GeMe₂)]₃, and Os₄(GeMe₂)₄(CO)₁₂

Abstract

The complex [(OC) 4 Os(GeMe 2 )] 2 (1) has been prepared from Na 2 [Os(CO) 4 ] and Me 2 GeCl 2 in THF. Photolysis of 1 in hexane affords the known [(OC) 3 Os(GeMe 2 )] 3 (4) as the major product, along with the new clusters Os 3 (GeMe 2 ) 2 (CO) 11 (3) and Os 4 (GeMe 2 ) 4 (CO) 12 (5). Pyrolysis of 1, in hexane at 100 °C, gives the same compounds except that Os 2 (GeMe 2 ) 3 -(CO) 6 (2) was also isolated, albeit in low yield. The structures of 1-5 have been determined; the configurations of 1, 2, and 4 are analogous to those previously found for group 8-group 14 congeners. The skeleton of 3 consists of two Os 2 Ge triangles that share a common osmium atom, that is, a "bow-tie" arrangement; the Os-Os lengths in 3 are crystallographically equivalent at 2.981(1) Å, and the Os-Ge lengths are 2.520(1) and 2.522(1) Å. The framework of 5 consists of a central triangulated (raftlike) Os 3 Ge 3 unit (similar to that in 4) to one Os atom of which is bound an (OC) 4 Os(GeMe 2 ) fragment so as to give an Os 2 Ge triangle that lies in the plane of the other metal atoms. The Os-Os bond length associated with this triangle is long (3.069(1) Å). The other Os-Os lengths in 4 range from 2.860(1) to 2.967(1) Å; the Os-Ge lengths are in the range 2.475(2)-2.584(2) Å. The 1 H NMR spectrum of 5 in toluene-d 8 is consistent with rotation of the (OC) 4 Os(GeMe 2 ) unit with respect to the rest of the molecule at temperatures above 60 °C.

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

“…The axial carbonyls in 1 show a marked leaning toward the SnMe 2 groups: the C(11)−Os(1)−C(13) angle is 162.8(5)°. We have observed the same leaning in the crystal structures of related compounds: for example, [(OC) 4 Os(GeMe 2 )] 2 and Os 2 (SnMe 2 ) 2 (CO) 7 (PMe 3 ) 22a and cis -Fe(CO) 4 (SnPh 3 ) 2 ,22b but it is not as pronounced as in cis -Ru(CO) 4 (GeCl 3 ) 2 22c…”

Germanium-Rich Pentaruthenium Carbonyl Clusters Including Ru5(CO)11(μ-GePh2)4(μ5-C) and Its Reactions with Hydrogen

“…Preparation of bimetallic nanoparticles from bimetallic molecular clusters as precursors has received much attention in recent years. − Bimetallic nanoparticles have been shown to exhibit superior catalytic activity under heterogeneous conditions. , Ruthenium combined with the group 14 elements, germanium, tin, or lead, has also been of interest in catalysis. − There is extensive literature on transition metal complexes containing group 14 elements; − however, there are only a few examples of ruthenium−germanium complexes and these consist only of mono-, di-, and triruthenium species. − …”

Synthesis and Structure of [Os(CO)4(SnPh2)]6: A Compound with an Unprecedented 12-Membered Ring of Metal Atoms

“…Compound 2 with a planar four-membered ring of metal atoms was the expected product. It has been found that reactions of [M(CO) 4 ] 2- (M = Fe, Ru, Os) with R 2 ECl 2 (E = Ge, Sn, Pb; R = Me, Bu t ) yield analogous derivatives with M 2 E 2 units. − The spectroscopic properties of 2 are unremarkable.

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“…The structural motifs exhibited by molecules with group 8 metals and the heavier 14 elements are many and diverse . Recent work from this laboratory has described the synthesis and structure of several Os−Ge and Os−Sn clusters with various skeletal geometries. , One of these, Os 4 (SnMe 2 ) 4 (CO) 14 , was envisaged as the result of dimerization of Os 2 (SnMe 2 ) 2 (CO) 7 , which in turn was the product of loss of CO from the precursor [Os(CO) 4 (SnMe 2 )] 2 …”