title: A copper(II) complex with a Cu-S₈ bond. Attenuated total reflectance, electron paramagnetic resonance, resonance Raman and atoms-in-molecule calculations.
abstract: Green [Cu(1,10-phenanthroline)2OH2](ClO4)2 (1) reacts with yellow elemental sulfur at room temperature in methanol to yield turquoise blue [Cu(1,10-phenanthro-line)2(S8)](ClO4)2 (2). A comparative study of the EPR spectra of 1 and 2 in solid state and in methanol glass indicates that the S8 unit in 2 is bound to the metal. High level DFT calculations show that the cation in 2 is five coordinate, distorted square pyramidal with S8 occupying the apical position. The crucial Cu(II)-S bond is around 2.9Å. Such long Cu(II)-S bonds occur in oxidized plastocyanin where it is considered to be bonding. Presence of a weak Cu-S8 bond is revealed in the resonance Raman spectra of 2. Satisfactory matching of the calculated and experimental IR spectra vindicates the theoretically derived structure of the cation in 2.
authors.affiliation: Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, Calcutta 700 032, India.
authors.forename: Nirmal K
authors.initials: NK
authors.lastname: Shee
authors.affiliation: Department of Pure and Applied Chemistry, Ladoke Akintola University of Technology, P.M.B. 4000, Ogbomoso, Nigeria.
authors.forename: Florence A O
authors.initials: FA
authors.lastname: Adekunle
authors.affiliation: Department of Applied Physics, Babasaheb Bhimrao Ambedkar University, Vidya Vihar, Lucknow 226 025, India.
authors.forename: Ravi
authors.initials: R
authors.lastname: Verma
authors.affiliation: Department of Applied Physics, Babasaheb Bhimrao Ambedkar University, Vidya Vihar, Lucknow 226 025, India.
authors.forename: Devesh
authors.initials: D
authors.lastname: Kumar
authors.affiliation: Department of Inorganic Chemistry, Indian Association for the Cultivation of Science, Calcutta 700 032, India. Electronic address: icdd@iacs.res.in.
authors.forename: Dipankar
authors.initials: D
authors.lastname: Datta
keywords: Copper(II); DFT; EPR; Elemental sulfur; Resonance Raman