The new redox systems (acac)2Ru(m-Q1)Ru(acac)2n (1n) and (acac)2Ru(m-Q2)Ru(acac)2n (2n) with Q1 = 1,10-phenanthroline-5,6-dione and Q2 = 1,10-phenanthroline-5,6-diimine were studied for n = +, 0, -, and 2- using UV-visible-NIR spectroelectrochem. and, in part, EPR and susceptometry. The ligands can bind the first metal (left) through the phenanthroline N atoms and the second metal (right) at the o-quinonoid chelate site. The neutral compds. are already different: Compd. 1 is formulated as a RuII(m-Q1).bul.-RuIII species with partially coupled semiquinone and Ru(III) centers. In contrast, a RuIII(m-Q2)2-RuIII structure is assigned to 2, which shows a weak antiferromagnetic spin-spin interaction (J = -1.14 cm-1) and displays an intense half-field signal in the EPR spectrum. The 1-electron reduced forms are also differently formulated as RuII(m-Q1)2-RuIII for 1- with a RuIII-typical EPR response and as RuII(m-Q2).bul.-RuII for 2- with a radical-type EPR signal at g = 2.0020. In contrast, both 12- and 22- can only be described as RuII(m-Q)2-RuII species. The monooxidized forms 1+ and 2+ show very similar spectroscopy, including a RuIII-type EPR signal. Although no unambiguous assignment was possible here for the alternatives RuII(m-Q)0RuIII, RuIII(m-Q)2-RuIV or RuIII(m-Q).bul.-RuIII, the last description is favored. The reasons for identical or different oxidn. state combinations are discussed. on SciFinder(R)
%0 Journal Article
%1 Ghumaan.2005b
%A Ghumaan, Sandeep
%A Sarkar, Biprajit
%A Patra, Srikanta
%A van Slageren, Joris
%A Fiedler, Jan
%A Kaim, Wolfgang
%A Lahiri, Goutam Kumar.
%D 2005
%J Inorganic Chemistry
%K EPR complex dinuclear oxidn phenanthrolinediimine phenanthrolinediimine;ruthenium phenanthrolinedione prepn ruthenium spectroelectrochem state unsym
%N 9
%P 3210--3214
%R 10.1021/ic048309x
%T Sensitive Oxidation State Ambivalence in Unsymmetrical Three-Center (M/Q/M) Systems (acac)2Ru(m-Q)Ru(acac)2n, Q = 1,10-Phenanthroline-5,6-dione or 1,10-Phenanthroline-5,6-diimine (n = +, 0, -, 2-)
%V 44
%X The new redox systems (acac)2Ru(m-Q1)Ru(acac)2n (1n) and (acac)2Ru(m-Q2)Ru(acac)2n (2n) with Q1 = 1,10-phenanthroline-5,6-dione and Q2 = 1,10-phenanthroline-5,6-diimine were studied for n = +, 0, -, and 2- using UV-visible-NIR spectroelectrochem. and, in part, EPR and susceptometry. The ligands can bind the first metal (left) through the phenanthroline N atoms and the second metal (right) at the o-quinonoid chelate site. The neutral compds. are already different: Compd. 1 is formulated as a RuII(m-Q1).bul.-RuIII species with partially coupled semiquinone and Ru(III) centers. In contrast, a RuIII(m-Q2)2-RuIII structure is assigned to 2, which shows a weak antiferromagnetic spin-spin interaction (J = -1.14 cm-1) and displays an intense half-field signal in the EPR spectrum. The 1-electron reduced forms are also differently formulated as RuII(m-Q1)2-RuIII for 1- with a RuIII-typical EPR response and as RuII(m-Q2).bul.-RuII for 2- with a radical-type EPR signal at g = 2.0020. In contrast, both 12- and 22- can only be described as RuII(m-Q)2-RuII species. The monooxidized forms 1+ and 2+ show very similar spectroscopy, including a RuIII-type EPR signal. Although no unambiguous assignment was possible here for the alternatives RuII(m-Q)0RuIII, RuIII(m-Q)2-RuIV or RuIII(m-Q).bul.-RuIII, the last description is favored. The reasons for identical or different oxidn. state combinations are discussed. on SciFinder(R)
@article{Ghumaan.2005b,
abstract = {The new redox systems [(acac)2Ru(\textgreek{m}-Q1)Ru(acac)2]n (1n) and [(acac)2Ru(\textgreek{m}-Q2)Ru(acac)2]n (2n) with Q1 = 1,10-phenanthroline-5,6-dione and Q2 = 1,10-phenanthroline-5,6-diimine were studied for n = +, 0, -, and 2- using UV-visible-NIR spectroelectrochem. and, in part, EPR and susceptometry. The ligands can bind the first metal (left) through the phenanthroline N atoms and the second metal (right) at the o-quinonoid chelate site. The neutral compds. are already different: Compd. 1 is formulated as a RuII(\textgreek{m}-Q1).bul.-RuIII species with partially coupled semiquinone and Ru(III) centers. In contrast, a RuIII(\textgreek{m}-Q2)2-RuIII structure is assigned to 2, which shows a weak antiferromagnetic spin-spin interaction (J = -1.14 cm-1) and displays an intense half-field signal in the EPR spectrum. The 1-electron reduced forms are also differently formulated as RuII(\textgreek{m}-Q1)2-RuIII for 1- with a RuIII-typical EPR response and as RuII(\textgreek{m}-Q2).bul.-RuII for 2- with a radical-type EPR signal at g = 2.0020. In contrast, both 12- and 22- can only be described as RuII(\textgreek{m}-Q)2-RuII species. The monooxidized forms 1+ and 2+ show very similar spectroscopy, including a RuIII-type EPR signal. Although no unambiguous assignment was possible here for the alternatives RuII(\textgreek{m}-Q)0RuIII, RuIII(\textgreek{m}-Q)2-RuIV or RuIII(\textgreek{m}-Q).bul.-RuIII, the last description is favored. The reasons for identical or different oxidn. state combinations are discussed. [on SciFinder(R)]},
added-at = {2019-07-15T13:41:23.000+0200},
author = {Ghumaan, Sandeep and Sarkar, Biprajit and Patra, Srikanta and {van Slageren}, Joris and Fiedler, Jan and Kaim, Wolfgang and Lahiri, Goutam Kumar.},
biburl = {https://puma.ub.uni-stuttgart.de/bibtex/2c667a58e5aeec47917babf1ccda86a5c/b_schwederski},
doi = {10.1021/ic048309x},
interhash = {b9a51e090dca12569f4cd3d0d0a0c0da},
intrahash = {c667a58e5aeec47917babf1ccda86a5c},
issn = {0020-1669},
journal = {Inorganic Chemistry},
keywords = {EPR complex dinuclear oxidn phenanthrolinediimine phenanthrolinediimine;ruthenium phenanthrolinedione prepn ruthenium spectroelectrochem state unsym},
number = 9,
pages = {3210--3214},
timestamp = {2019-07-15T11:42:10.000+0200},
title = {Sensitive Oxidation State Ambivalence in Unsymmetrical Three-Center (M/Q/M) Systems [(acac)2Ru(\textgreek{m}-Q)Ru(acac)2]n, Q = 1,10-Phenanthroline-5,6-dione or 1,10-Phenanthroline-5,6-diimine (n = +, 0, -, 2-)},
volume = 44,
year = 2005
}