SYNTHESIS, STRUCTURE, AND REACTIVITY OF CHIRAL RHENIUM AMINE COMPLEXES OF THE FORMULA [(ETA-5-C5H5)RE(NO)(PPH3)(NRR'R'')]+TFO-
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abstract
Reactions of (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 [(5-C5H5)Re(NO)(PPh3)(NRRR)]+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-15NH3 are studied in detail. The crystal structure of 3f (monoclinic, P21/n, a = 13.925 (2) , b = 24.467 (3) , c = 8.148 (1) , = 93.398 (4), Z = 4) shows P-Re-N-H and ON-Re-N-H torsion angles of-52 and 40, and a N-H-OTf hydrogen bond (H-O 2.37 (5) ). Reactions of 3a,b,f with (CH3CH2)4N+CN- and PPN+N3- (PPN = Ph3P-N-PPh3) give the substitution products (5-C5H5)-Re(NO)(PPh3)(CN) (4, 86-94%) and (5-C5H5)Re(NO)(PPh3)(N3) (5, 61-98%). Reaction of (5-C5H5)Re(NO)(PPh3)(CH3) with HBF4OEt2 and then PPN+N3- in chlorobenzene also gives 5 (67%). Reaction of (+)-(S)-3b and (CH3CH2)4N+ CN- gives (+)-(5)-4 (>98% ee, retention of configuration). 1991, American Chemical Society. All rights reserved.