SYNTHESIS, STRUCTURE, AND REACTIVITY OF CHIRAL RHENIUM AMINE COMPLEXES OF THE FORMULA [(ETA-5-C5H5)RE(NO)(PPH3)(NRR'R'')]+TFO-

Reactions of (eta-5-C5H5)Re(NO)(PPh3)(OTf) (2) and (a) ammonia, (b) methylamine, (c) [(trimethylsilyl)methyl]amine, (d) aniline, (e) isopropylamine, (f) dimethylamine, (g) dibenzylamine, (h) pyrrolidine, and (i) trimethylamine give amine complexes [(eta-5-C5H5)Re(NO)(PPh3)(NRR'R")]+TfO- (3,55-99%). An analogous reaction of optically active (+)-(R)-2 and methylamine gives (+)-(S)-3b (79%, > 98% ee, retention of configuration). The spectroscopic properties of 3a-i and isotopomer 3a-(NH3)-N-15 are studied in detail. The crystal structure of 3f (monoclinic, P2(1)/n, a = 13.925 (2) angstrom, b = 24.467 (3) angstrom, c = 8.148 (1) angstrom, beta = 93.398 (4)-degrees, Z = 4) shows P-Re-N-H and ON-Re-N-H torsion angles of -52 and 40-degrees, and a N..H..OTf hydrogen bond (H..O 2.37 (5) angstrom). Reactions of 3a,b,f with (CH3CH2)4N+CN- and PPN+N3- (PPN = Ph3P-N-PPh3) give the substitution products (eta-5-C5H5)-Re(NO)(PPh3)(CN) (4, 86-94%) and (eta-5-C5H5)Re(NO)(PPh3)(N3) (5, 61-98%). Reaction of (eta-5-C5H5)Re(NO)(PPh3)(CH3) with HBF4.OEt2 and then PPN+N3- in chlorobenzene also gives 5 (67%). Reaction of (+)-(S)-3b and (CH3CH2)4N+ CN- gives (+)-(S)-4 (> 98% ee, retention of configuration).