Synthesis and Structure of an Enantiopure Dirhodium Loop with Unusual Axial Coordination

摘要

The crystals of enantiopure SS-[cis-Rh2(Ph2C6H4)2(O2CC2F4CO2)]2((CH3)2CHCH2NH2)3(1) were obtained from the reaction of S-[cis-Rh2(Ph2C6H4)2(CH3CN)6]BF4(S-2) and(Et4N)2(O2CC2F4CO2) in CH2Cl2/CH3OH under the presence of sec-butyl amine.Compound 1 crystallizes in orthorhombic,space group P212121 with a = 16.880(5),b = 28.728(9),c = 20.475(6) ,V = 9929(5) 3,Z = 4,C95H96Cl5F8N3O8.50P4Rh4,Mr = 2280.52,Dc = 1.526 g/cm3,F(000) = 4608 and μ(MoKα) = 0.922 mm-1.The final R = 0.0488 and wR = 0.1164 for 17204 observed reflections with I > 2σ(I) and R = 0.0814 and wR = 0.1374 for all data with absolute structure parameter =-0.04(3).Compound 1 contains two inherently chiral S-[cis-Rh2(Ph2C6H4)2] moieties which are connected by two(O2CC2F4CO2) dicarboxylate ligands in the equatorial positions.One of the dirhodium units with Rh-Rh distance of 2.5445(8)  is further coordinated by a sec-butyl amine in each axial position.Another dirohdium unit has only one axial sec-butyl amine ligand,and its Rh-Rh distance is 2.5079(9) .