Carbene complexes XXIII. Preparation, characterisation, and structures of the enetetramine-derived carbenerhodium(I) chloride complexes R)3>, trans-R'2)>, and 2(323)R2>> (LR or R'2 = (R = CH2Ph or Et, R' = Me) and L(323)R =

Article abstract of DOI:10.1016/0022-328X(93)86084-U

From <2> and the enetetramine L^Me₂, L^Et₂, L^CH2Ph₂, or L^(323)CH2Ph₂ the crystalline complexes R)₃> , <2<μ-L^(323)CH2Ph₂>> (2), or trans-R)₂> have been obtained in high yield .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) Angstroem; (iii) in the bis(carbene) complexes 4 and 5, as well as in 2, the five-membered almost planar 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^o; and (iv) the sum of the bond angles at each C_carb or N is close to 360^o.