CRYSTAL-STRUCTURES OF DIASTEREOMERIC STYRENE COMPLEXES OF THE CHIRAL RHENIUM FRAGMENT [(ETA(5)-C5H5)RE(NO)(PPH(3))](- EFFECT OF LIGATING ENANTIOFACE UPON BONDING AND CONFORMATION() )

The styrene complex [(eta(5)-C5H5)Re(NO)(PPh(3))H2C = CHC6H5)](BF4-)-B -+ (1) can exist as two configurational diastereomers, RS,SR and RR,SS , that differ in the C=C enantioface bound to rhenium. Crystal structu res show that the eleven atom (eta(5)-C5H5)Re(NO)-(P)(C<($)triple over dot-C) units of each are virtually superimposable ((RS,SR)-1; triclin ic, P ($) over bar 1, a=11.438(2) Angstrom, b=12.449(3) Angstrom, c=10 .712(2) Angstrom, alpha=99.86 (1)degrees, beta=105.01(1)degrees, gamma =99.43(1)degrees, Z=2; (RR,SS)-1; monoclinic, P2(1)/n (No. 14), a=9.67 3(1) Angstrom, b=9.517(1) Angstrom, c=30.928(2) Angstrom, beta=94.98(1 )degrees, Z=4). Steric interactions between the styrene phenyl group a nd cyclopentadienyl ligand in the less stable diastereomer (RR,SS)-1 a re apparent. These and other structural features are analyzed in detai l.