title: 1H NMR, EPR, UV-Vis, and Electrochemical Studies of Imidazole Complexes of Ru(III). Crystal Structures of cis-[(Im)(2)(NH(3))(4)Ru(III)]Br(3) and [(1MeIm)(6)Ru(II)]Cl(2).2H(2)O.
abstract: Comparisons of the spectroscopic properties of a number of Ru(III) complexes of imidazole ligands provide methods of distinguishing between various types of bonding that can occur in proteins and nucleic acids. In particular, EPR and (1)H NMR parameters arising from the paramagnetism of Ru(III) should aid in determining binding sites of Ru(III) drugs in macromolecules. Electrochemical studies on several imidazole complexes of ruthenium suggest that imidazole may serve as a significant pi-acceptor ligand in the presence of anionic ligands. Crystal structures are reported on two active immunosuppressant complexes. cis-[(Im)(2)(NH(3))(4)Ru(III)]Br(3) crystallizes in the triclinic space group P&onemacr; (No. 2) with the cell parameters a = 8.961(2) Å, b = 12.677(3) Å, c = 7.630(2) Å, alpha = 98.03(2) degrees, beta = 100.68(2) degrees, gamma = 81.59(2) degrees, and Z = 2 (R = 0.044). [(1MeIm)(6)Ru(II)]Cl(2).2H(2)O crystallizes in the monoclinic space group P2(1)/n (No. 14) with the cell parameters a = 7.994(2) Å, b = 13.173(4) Å, c = 14.904(2) Å, beta = 97.89(1) degrees, and Z = 2 (R = 0.052). The average Ru(II)-N bond distance is 2.106(8) Å.
authors.affiliation: Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02167, Department of Chemistry, Northwestern University, Evanston, Illinois 60208, and Procept, Inc., Cambridge, Massachusetts 02139.
authors.forename: M. J.
authors.initials: MJ
authors.lastname: Clarke
authors.forename: V. M.
authors.initials: VM
authors.lastname: Bailey
authors.forename: P. E.
authors.initials: PE
authors.lastname: Doan
authors.forename: C. D.
authors.initials: CD
authors.lastname: Hiller
authors.forename: K. J.
authors.initials: KJ
authors.lastname: LaChance-Galang
authors.forename: H.
authors.initials: H
authors.lastname: Daghlian
authors.forename: S.
authors.initials: S
authors.lastname: Mandal
authors.forename: C. M.
authors.initials: CM
authors.lastname: Bastos
authors.forename: D.
authors.initials: D
authors.lastname: Lang