330836-64-1Relevant academic research and scientific papers
Synthesis, redox chemistry and EPR spectroscopy of the mixedsandwich complexes (ri-arene)(T|-cycloheptatrienyl)metal(z+) (M = Cr or Mo;z = 1 or 2): Crystal structures of the redox pair [Cr(Ti-C6H5Me)(η-C7H6C 6H4Me-4)][PF6]n (n = I or 2)
Beddoes, Roy L.
, p. 4669 - 4676 (2007/10/03)
The mixed sandwich complexes [M(n-arene)(n-C7H6R')r (M = Cr, R' = H, arene = C6H4Me2-l,4, la; or C6H3Me31,3,5, 2a; R' = C6H4Me-4, arene = C6H5Me, 3a;M = Mo, R' = H, arene = C6H3Me3-l,3,5,4a) were prepared by reflux of [M(CO)3(n-C7H6R')r in the appropriate arene solvent. Reflux of [MoOi-CsHjMeXri-C,!)] with an excess of HOCBu' in acetone affords [Mo(n-C6H3BuVl,3,5)(n-C7H7)]+, 5a cycijc voltammetric studies in NCMe reveal that each of la, 2a, 3a and 5a undergoes reversible one-electron oxidation processes to give the corresponding, isolable 17-electron radical dications, Ib, 2b, 3b and 5b which have been characterised by EPR spectroscopy. NMR data for the 18-electron monocations suggest an enhanced electron density at the arene ring in the chromium derivatives by comparison with molybdenum analogues and this is reflected in the stability of complexes la, 2a and 3a towards arene displacement reactions. The crystal structure of 3a reveals only a small asymmetry in the average chromium-toring carbon bond lengths for the arene and cycloheptatrienyl rings. One-electron oxidation of 3a to give 3b results in a small increase in metal-to-ring distances (ca. 0.02 A) consistent with a HOMO which is essentially non-bonding with respect to the metal-ring interaction. The Royal Society of Chemistry 2000.
