The reactivity of complexed carbocycles XII: mono- and dimetallic cyclooctatetraene complexes of manganese and rhenium: synthesis, structure and dynamic behaviour

On irradiation of C5Me5Re(CO)(3) in the presence of C8H8, complexes C5Me5Re (CO)(2)(eta(2)-C8H8) (1) as well as C5Me5Re(eta(6-)C(8)H(8)) (2) are formed . The latter was characterised by a crystal structure analysis. The reactio n of K-2[C8H8] with [Re-Br(CO)(3)(THF)(2)] yields a dimetallic complex (CO) (3)Re(mu-C8H8)Re(CO)(3) (3), which has a syn-bridging structure and is flux ional in solution. The manganese complex (eta(5)-C8H9)Mn(CO)(3) can be depr otonated to give the anion [eta(4)-C8H8)Mn(CO)(3)](-), which is used as a b uilding block for heterodimetallic complexes. It reacts with cationic 12-el ectron fragments [LnM](+) to give dimetallic compounds [(CO)(3)Mn(mu-C8H8)M Ln]. These complexes have either syn- or anti-bridging structures. Both str uctural types exhibit dynamic behaviour in solution. The carbonyl groups of complex (CO)(3)Mn(mu-C8H8)Rh(CO)(2) were labelled with (CO)-C-13 and shown to undergo very slow intermetallic scrambling. (C) 1999 Elsevier Science S .A. All rights reserved.