CARBENE COMPLEXES .23. PREPARATION, CHARACTERIZATION, AND STRUCTURES OF THE ENETETRAMINE-DERIVED CARBENERHODIUM(I) CHLORIDE COMPLEXES [RHCL(L(R))(3)], TRANS-[RHCL(CO)(L(2)R')], AND [(RHCL(COD))(2)(MU-L(2)(323)R)] L(2)R OR R'=CN(R OR R')(CH2)2NR(OR R') (R = CH2PH OR ET, R' = ME) AND L((323)R)=CN(R)(CH2)3N(CH2)2N(CH2)3N(R)C (R = CH2PH)]

From [(Rh(A-Cl)(COD))2] and the enetetramine L2Me, L2Et, L2CH2Ph, or L 2(323)CH2Ph the crystalline complexes [RhCl(L(R))3] [R = CH2Ph (1) or Et (3)], [{RCl(COD)}2{mu-L2(323)CH2Ph}] (2), or trans-[RhCl(CO)(L(R)2] [R = CH2Ph (4) or Me (5)] have been obtained in high yield [L(R) = CN (R)(CH2)2NR and L(323)R = CN(R)(CH2)3N(CH2)2N(CH2)3N(R)C]. Complex 2 p rovides a rare example of a bridging bis(carbene)dimetal complex and t he 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) angstrom; (iii) in the bis(carbene) complexes 4 a nd 5, as well as in 2, the five-membered almost planar C(carb)NC2N rin g (or fragment for 2) is approximately orthogonal to the plane contain ing Rh, Cl, and C(carb), while in the tris(carbene) complexes 1 and 3 the mutually trans-carbene ligands are twisted from a parallel arrange ment by 49-degrees; and (iv) the sum of the bond angles at each C(carb ) or N is close to 360-degrees.