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Title: Electronic influences of bridging and chelating diimine ligand coordination in formamidinate-bridged Rh 2 (II,II) dimers

We report two new formamidinate-bridged Rh 2 II,II complexes, cis-[Rh 2 II,II(μ-DTolF) 2(μ-np) 2] 2+ (3; DTolF = N,N'-di-p-tolylformamidinate; np = 1,8-naphthyridine) and cis-[Rh 2 II,II(μ-DTolF) 22-dap) 2] 2+ (4; dap = 1,12-diazaperylene), were synthesized from cis-[Rh 2 II,II(μ-DTolF) 2(CH 3CN) 6](BF 4) 2 (1), and their properties were compared to those of cis-[Rh 2 II,II(μ-DTolF) 2(phen) 2](BF 4) 2 (2). Density functional theory (DFT) and electrochemical analyses support the description of the highest occupied molecular orbitals (HOMOs) of 3 and 4 as possessing contributions from the metals and formamidinate bridging ligands, with Rh 2/form character, and lowest unoccupied molecular orbitals (LUMOs) localized on the respective diimine ligand np and dap π* orbitals. Both 3 and 4 display strong, low energy Rh 2/form → diimine(π*) metal/ligand-to-ligand charger transfer ( 1ML–LCT) transitions with maxima at 566 nm (ε = 3600 M -1 cm -1) for 3 and at 630 nm (ε = 2900 M -1 cm -1) for 4 in CH 3CN. Time dependent-DFT (TD-DFT) calculations support these assignments. Finally, the ability of both the bridging np and chelating dap diimine ligands to produce strong absorption of these Rh 2 II,II complexes throughout the visible region is potentially useful formore » the development of new photocatalysts for H 2 production and photochemotherapeutics.« less
 [1] ; ORCiD logo [2] ;  [3] ; ORCiD logo [1]
  1. The Ohio State Univ., Columbus, OH (United States). Department of Chemistry and Biochemistry
  2. Texas A & M Univ., College Station, TX (United States). Department of Chemistry
  3. University of Houston, TX (United States). Department of Chemistry
Publication Date:
Grant/Contract Number:
SC0010542; SC0010721
Accepted Manuscript
Journal Name:
Additional Journal Information:
Journal Volume: 103; Journal Issue: PA; Journal ID: ISSN 0277-5387
Research Org:
The Ohio State Univ., Columbus, OH (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
14 SOLAR ENERGY; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Dirhodium; Naphthyridine; Diazaperylene; Light absorption; Electrochemistry
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1359777