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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
Authors:
 [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
Type:
Accepted Manuscript
Journal Name:
Polyhedron
Additional Journal Information:
Journal Volume: 103; Journal Issue: PA; Journal ID: ISSN 0277-5387
Publisher:
Elsevier
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
Language:
English
Subject:
14 SOLAR ENERGY; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; Dirhodium; Naphthyridine; Diazaperylene; Light absorption; Electrochemistry
OSTI Identifier:
1430205
Alternate Identifier(s):
OSTI ID: 1359777

White, Travis A., Dunbar, Kim R., Thummel, Randolph P., and Turro, Claudia. Electronic influences of bridging and chelating diimine ligand coordination in formamidinate-bridged Rh2 (II,II) dimers. United States: N. p., Web. doi:10.1016/j.poly.2015.10.015.
White, Travis A., Dunbar, Kim R., Thummel, Randolph P., & Turro, Claudia. Electronic influences of bridging and chelating diimine ligand coordination in formamidinate-bridged Rh2 (II,II) dimers. United States. doi:10.1016/j.poly.2015.10.015.
White, Travis A., Dunbar, Kim R., Thummel, Randolph P., and Turro, Claudia. 2015. "Electronic influences of bridging and chelating diimine ligand coordination in formamidinate-bridged Rh2 (II,II) dimers". United States. doi:10.1016/j.poly.2015.10.015. https://www.osti.gov/servlets/purl/1430205.
@article{osti_1430205,
title = {Electronic influences of bridging and chelating diimine ligand coordination in formamidinate-bridged Rh2 (II,II) dimers},
author = {White, Travis A. and Dunbar, Kim R. and Thummel, Randolph P. and Turro, Claudia},
abstractNote = {We report two new formamidinate-bridged Rh2II,II complexes, cis-[Rh2II,II(μ-DTolF)2(μ-np)2]2+ (3; DTolF = N,N'-di-p-tolylformamidinate; np = 1,8-naphthyridine) and cis-[Rh2II,II(μ-DTolF)2(κ2-dap)2]2+ (4; dap = 1,12-diazaperylene), were synthesized from cis-[Rh2II,II(μ-DTolF)2(CH3CN)6](BF4)2 (1), and their properties were compared to those of cis-[Rh2II,II(μ-DTolF)2(phen)2](BF4)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 Rh2/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 Rh2/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 CH3CN. 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 Rh2II,II complexes throughout the visible region is potentially useful for the development of new photocatalysts for H2 production and photochemotherapeutics.},
doi = {10.1016/j.poly.2015.10.015},
journal = {Polyhedron},
number = PA,
volume = 103,
place = {United States},
year = {2015},
month = {10}
}