Carbene complexes: XXIII. Preparation, characterisation, and structures of the enetetramine-derived carbenerhodium(I) chloride complexes [RhCl(L R) 3], trans-[RhCl(CO)(L 2R′)], and [{RhCl(COD)} 2{μ-L 2(323)R}] [L 2R or R′ = [formula omitted]2) 2N R(or R′) (R  CH 2)Ph or Et, R′  Me) and L (323)R  [formula omitted](CH 2) 2[formula omitted](CH 2) 3N(R)C (R  CH 2Ph)

Abstract

From [{Rh(μ-Cl)COD)} 2 and the enetetramine L 2 Me, L 2 Et, L 2 CH 2Ph , or L( 2 323)CH 2Ph) the crystalline complexes [RhCl(L R) 3][R  CH 2Ph ( 1) or Et ( 3)], [{RCl(COD)} 2{μL 2 (323)CH 2Ph }] ( 2), or trans-[RhCl(CO)(L R) 2] [R  CH 2Ph ( 4) or Me ( 5)] have been obtained in high yield [L R CN(R)(CH 2) 2N R and L{(su323)R}  CN(R)(CH 2) 3N (CH 2) 2 N(CH 2) 3N(R)C ]. Complex 2 provides a rare example of a bridging bis(carbene) dimetal complex and the first for one derived from an enetetramine. The X-ray structures of 1–5 show that (i) the mutually trans-RhC carb bonds for 1 and 3 are longer than the cis-; (ii) the RhCl bond lengths range from 2.268(4) ( 5) to 2.464(6) (3)Å; (iii) in the bis(carbene) complexes 4 and 5, as well as in 2, the five-membered almost planar C carb,NC 2N ring (or fragment for 2) is approximately orthogonal to the plane containing Rh, Cl, and C carb, while in the tris(carbene) complexes 1 and 3 the mutually trans-carbene ligands are twisted from a parallel arrangement by 49°; and (iv) the sum of the bond angles at each C carb or N is close to 360°.