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Title: Molecular and electronic structure of Re 2Br 4(PMe 3) 4

The dinuclear rhenium(II) complex Re 2Br 4(PMe 3) 4 was prepared from the reduction of [Re 2Br 8] 2– with ( n-Bu 4N)BH 4 in the presence of PMe 3 in propanol. The complex was characterized by single-crystal X-ray diffraction (SCXRD) and UV–visible spectroscopy. It crystallizes in the monoclinic C2/c space group and is isostructural with its molybdenum and technetium analogues. The Re–Re distance (2.2521(3) Å) is slightly longer than the one in Re 2Cl 4(PMe 3) 4 (2.247(1) Å). The molecular and electronic structure of Re 2X 4(PMe 3) 4 (X = Cl, Br) were studied by multiconfigurational quantum chemical methods. The computed ground-state geometry is in excellent agreement with the experimental structure determined by SCXRD. The calculated total bond order (2.75) is consistent with the presence of an electron-rich triple bond and is similar to the one found for Re 2Cl 4(PMe 3) 4. The electronic absorption spectrum of Re 2Br 4(PMe 3) 4 was recorded in benzene and shows a series of low-intensity bands in the range 10 000–26 000 cm –1. The absorption bands were assigned based on calculations of the excitation energies with the multireference wave functions followed by second-order perturbation theory using the CASSCF/CASPT2more » method. As a result, calculations predict that the lowest energy band corresponds to the δ* → σ* transition, while the next higher energy bands were attributed to the δ* → π*, δ → σ*, and δ → π* transitions.« less
Authors:
 [1] ;  [1] ;  [2] ;  [1] ;  [3] ;  [3] ;  [3] ;  [1] ;  [4]
  1. Univ. of Nevada, Las Vegas, NV (United States)
  2. College de France, Paris Cedex (France)
  3. Uppsala Univ., Uppsala (Sweden)
  4. Univ. of Nevada, Las Vegas, NV (United States); Argonne National Lab. (ANL), Argonne, IL (United States)
Publication Date:
Grant/Contract Number:
AC02-06CH11357
Type:
Accepted Manuscript
Journal Name:
Inorganic Chemistry
Additional Journal Information:
Journal Volume: 55; Journal Issue: 14; Journal ID: ISSN 0020-1669
Publisher:
American Chemical Society (ACS)
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
Swedish Research Council (SRC); Uppsala University; Knut and Alice Wallenberg Foundation; USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Rhenium; DFT; electronic structure; metal-metal bonds; single crystal X-ray diffraction
OSTI Identifier:
1339564