90.
The thermally stable solids Re
2(CO)
8[μ-InRe(CO)
5]
2 and Re
4(CO)
12[μ
3-InRe(CO)
5]
4 could be obtained by treatment of In with Re
2(CO)
10 in a bomb tube. A mechanism of the formation of the latter cluster from the first one is proposed. Compared with Re
2(CO)
8[μ-InRe(CO)
5]
2, Re
4(CO)
12[μ
3_InRe(CO)
5]
4 shows in polar solvents an unusual high stability, which can be explained by the higher coordination number of In with rhenium carbonyl ligands. Re
4(CO)
12-[μ
3-InRe(CO)
5]
4 dissolves monomerically in acetone, where as Re
2(CO)
8[μ-InRe(CO)
5]
2 dissociates yielding Re(CO)
5? anions. Single-crystal X-ray analyses of Re
4(CO)
12[μ
3-InRe(CO)
5]
4 establish the metal skeleton. The central molecular fragment Re
4(CO)
12 contains a tetrahedral arrangement of four bonded Re atoms [ReRe 302.8 (5) pm]. The triangles of this fragment are capped with a μ
3-InRe(CO)
5 group each [InRe(terminal) 273.5 (7) pm; InRe (polyhedral) 281.8 (7) pm]. The bridging type of In atoms with the Re
4 tetrahedron and the metal skeleton was realized for the first time. By treating Re
4(CO)
12[μ
3-InRe(CO)
5]
4 with Br
2 the existence of Re(CO)
5 ligands could be proved by isolating BrRe(CO)
5.
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