Consanguineous Families of Coordinated Carbon: A ReC4Re Assembly That Is Isolable in Three Oxidation States, Including Crystallographically Characterized ReCCCCRe and +ReCCCCRe+ Adducts and a Radical Cation in Which Charge Is Delocalized between Rhenium Termini
- Additional Document Info
- View All
Reaction of (5-C5Me5)Re(NO)(PPh3)(C CH) and Cu(OAc)2 (1.5 equiv, 80 C, pyridine) gives the orange-brown ReC4Re complex (5-C5Me5)Re(NO)(PPh3)(C CC C)(Ph3P)(ON)Re(5-C5Me5) (2, 88%) as a 50:50 diastereomer mixture. Crystallization affords (SS,RR)-2 2CH2Cl2 and solutions enriched in (SR,RS)-2 (meso). Addition of Ag+PF6- ( 2 equiv) yields deep blue (SS,RR)- and (SR,RS)-22+2PF6- (86%), which give two geometric isomers (62:38, 89:11; CD2Cl2, -93 C) about the +Re = C = C = C = C = Re+ linkages. Crystal structures of (SS,RR)-2 2CH2Cl2 and (SS,RR)-22+2PF6- show ReC4Re units with bond angles (169-178) and lengths (C C, 1.202(7); C-C 1.398(5); C = C 1.260-1.305(10) ) near those of butadiyne or cumulenes. Natural bond order analysis and topological electron density calculations confirm the valence formulations. Reactions of (SS,RR)-2 with (SS,RR)-22+2PF6- or Ag+PF6- (1 equiv) give a green radical cation (SS,RR)-2.+PF6- ( = 1.74 (B); Faraday method). Edata yield a K(c) value of 1.1 x 109 (CH2Cl2, 22.5 C) for the comproportionation. ESR spectra show undecets with A(iso,Re) values (98 G) half those of related monorhenium radical cations, indicating spin delocalization over two rheniums (I = 5/2). Accordingly, IR spectra give only one (NO) band, positioned between those of 2 and 22+2PF6- (CH2Cl2, 1665 vs 1623/1719 cm-1). Near IR spectra show unique solvent-independent bands (883, 1000, 1200 nm; 15000, 9400, 3200 M-1 cm-1). Sodium naphthalenide reduces (SS,RR)- or (SR,RS)-2.+PF6- to (SS,RR)- or (SR,RS)-2, establishing configurational stability. These and related data are analyzed in detail.
Journal of the American Chemical Society
author list (cited authors)
Brady, M., Weng, W., Zhou, Y., Seyler, J. W., Amoroso, A. J., Arif, A. M., ... Gladysz, J. A.
complete list of authors
Brady, Monika||Weng, Weiqing||Zhou, Yuanlin||Seyler, Jeffery W||Amoroso, Angelo J||Arif, Atta M||Böhme, Marlis||Frenking, Gernot||Gladysz, JA