Synthesis and Characterisation of Molecular Polarised-Covalent Thorium-Rhenium and -Ruthenium Bonds

Separate reactions of [Th{N(CH2CH2NSiMe2But)(2)(CH2CH2NSi(Me)(Bu-t)(mu-CH2)](2) (1) with [Re(eta(5)-C5H5)(2)(H)] (2) or [Ru(eta(5)-C5H5)(H)(CO)(2)] (3) produced, by alkane elimination, [Th(Tren(DMBS))Re(eta(5)-C5H5)(2)] (ThRe, Tren(DMBS) = {N(CH2CH2NSiMe2But)(3)}(3-)), and [Th(Tren(DMBS))Ru(eta(5)-C5H5)(CO)(2)] (ThRu), which were isolated in crystalline yields of 71% and 62%, respectively. Complex ThRe is the first example of a molecular Th-Re bond to be structurally characterised, and ThRu is only the second example of a structurally authenticated Th-Ru bond. By comparison to isostructural U-analogues, quantum chemical calculations, which are validated by IR and Raman spectroscopic data, suggest that the Th-Re and Th-Ru bonds reported here are more ionic than the corresponding U-Re and U-Ru bonds.

Automated summary

Two new thorium-rhenium and thorium-ruthenium compounds were synthesized through alkane elimination reactions, with crystalline yields of 71% and 62% respectively. The molecular Th-Re and Th-Ru bonds were structurally characterized and found to be more ionic than the corresponding U-Re and U-Ru bonds, as indicated by quantum chemical calculations validated by IR and Raman spectroscopic data.