The new redox-active complexes [RuH(CO)(EPh3)2(m-Q2-)RuH(CO)(EPh3)2], E = P (1) and E = As (2) with the bis-chelate bridging ligand Q2-= 1,4-dioxido-9,10-anthraquinone were prepd. and characterized. The related compd. [RuCl(CO)(PPh3)2(m-Qx2-)RuCl(CO)(PPh3)2] (4) with E = P and Qx2- = 5,8-dioxido-1,4-naphthoquinone 4 revealed trans-positioned PPh3 groups. The electrogenerated 1-electron oxidized states 1+ and 2+ were examd. using spectroelectrochem. techniques (EPR, IR and UV/visible/NIR). In situ EPR studies gave spectra with 31P or 75As hyperfine splitting of $\sim$16 G, small 99,101Ru coupling and small g-anisotropy in the frozen soln. state. The 31P and 75As hyperfine values reflect axial positioning of the four Ru-E bonds relative to the plane of an anthrasemiquinone bridge. Single CO stretching bands around 1910 cm-1 of the precursors 1 and 2 shift by $\sim$25 cm-1 to higher energies on oxidn. The direction, uniformity and the extent of the shifts confirm ligand bridge-based oxidn. Absorbance by the cations in the near IR region is thus assigned to intra-ligand transitions of ruthenium(II)-bonded anthrasemiquinones and not to intervalence charge transfer of mixed-valent species. Ruthenium(II) stabilization by CO and EPh3 is made responsible for the anthrasemiquinone formation instead of metal-centered oxidn. [on SciFinder(R)]
%0 Journal Article
%1 Kamatchi.2017
%A Kamatchi, Thangavel Sathiya
%A Mondal, Sudipta
%A Scherer, Thomas
%A Bubrin, Martina
%A Natarajan, Karuppannan
%A Kaim, Wolfgang.
%D 2017
%J Chemistry - A European Journal
%K IR absorption complex complex;ruthenium crystal dioxidoanthraquinone potential prepn redox ruthenium structure
%N 70
%P 17810--17816
%R 10.1002/chem.201703888
%T Near-Infrared-Absorbing Organometallic Diruthenium Complex Intermediates: Evidence for Bridging Anthrasemiquinone Formation and against Mixed Valency
%V 23
%X The new redox-active complexes [RuH(CO)(EPh3)2(m-Q2-)RuH(CO)(EPh3)2], E = P (1) and E = As (2) with the bis-chelate bridging ligand Q2-= 1,4-dioxido-9,10-anthraquinone were prepd. and characterized. The related compd. [RuCl(CO)(PPh3)2(m-Qx2-)RuCl(CO)(PPh3)2] (4) with E = P and Qx2- = 5,8-dioxido-1,4-naphthoquinone 4 revealed trans-positioned PPh3 groups. The electrogenerated 1-electron oxidized states 1+ and 2+ were examd. using spectroelectrochem. techniques (EPR, IR and UV/visible/NIR). In situ EPR studies gave spectra with 31P or 75As hyperfine splitting of $\sim$16 G, small 99,101Ru coupling and small g-anisotropy in the frozen soln. state. The 31P and 75As hyperfine values reflect axial positioning of the four Ru-E bonds relative to the plane of an anthrasemiquinone bridge. Single CO stretching bands around 1910 cm-1 of the precursors 1 and 2 shift by $\sim$25 cm-1 to higher energies on oxidn. The direction, uniformity and the extent of the shifts confirm ligand bridge-based oxidn. Absorbance by the cations in the near IR region is thus assigned to intra-ligand transitions of ruthenium(II)-bonded anthrasemiquinones and not to intervalence charge transfer of mixed-valent species. Ruthenium(II) stabilization by CO and EPh3 is made responsible for the anthrasemiquinone formation instead of metal-centered oxidn. [on SciFinder(R)]
@article{Kamatchi.2017,
abstract = {The new redox-active complexes [RuH(CO)(EPh3)2(\textgreek{m}-Q2-)RuH(CO)(EPh3)2], E = P (1) and E = As (2) with the bis-chelate bridging ligand Q2-= 1,4-dioxido-9,10-anthraquinone were prepd. and characterized. The related compd. [RuCl(CO)(PPh3)2(\textgreek{m}-Qx2-)RuCl(CO)(PPh3)2] (4) with E = P and Qx2- = 5,8-dioxido-1,4-naphthoquinone 4 revealed trans-positioned PPh3 groups. The electrogenerated 1-electron oxidized states 1+ and 2+ were examd. using spectroelectrochem. techniques (EPR, IR and UV/visible/NIR). In situ EPR studies gave spectra with 31P or 75As hyperfine splitting of $\sim$16 G, small 99,101Ru coupling and small g-anisotropy in the frozen soln. state. The 31P and 75As hyperfine values reflect axial positioning of the four Ru-E bonds relative to the plane of an anthrasemiquinone bridge. Single CO stretching bands around 1910 cm-1 of the precursors 1 and 2 shift by $\sim$25 cm-1 to higher energies on oxidn. The direction, uniformity and the extent of the shifts confirm ligand bridge-based oxidn. Absorbance by the cations in the near IR region is thus assigned to intra-ligand transitions of ruthenium(II)-bonded anthrasemiquinones and not to intervalence charge transfer of mixed-valent species. Ruthenium(II) stabilization by CO and EPh3 is made responsible for the anthrasemiquinone formation instead of metal-centered oxidn. [on SciFinder(R)]},
added-at = {2022-06-15T11:26:56.000+0200},
author = {Kamatchi, Thangavel Sathiya and Mondal, Sudipta and Scherer, Thomas and Bubrin, Martina and Natarajan, Karuppannan and Kaim, Wolfgang.},
biburl = {https://puma.ub.uni-stuttgart.de/bibtex/2e409b367d93061cf277dcf2c62f07f1b/huebleriac},
doi = {10.1002/chem.201703888},
interhash = {26b06b15e3b3d8e89165db90a87b2e8e},
intrahash = {e409b367d93061cf277dcf2c62f07f1b},
issn = {0947-6539},
journal = {Chemistry - A European Journal},
keywords = {IR absorption complex complex;ruthenium crystal dioxidoanthraquinone potential prepn redox ruthenium structure},
number = 70,
pages = {17810--17816},
timestamp = {2022-06-15T09:26:56.000+0200},
title = {Near-Infrared-Absorbing Organometallic Diruthenium Complex Intermediates: Evidence for Bridging Anthrasemiquinone Formation and against Mixed Valency},
volume = 23,
year = 2017
}
