TY - JOUR
T1 - Probing valence and spin situations in selective ruthenium-iminoquinonoid frameworks. An experimental and DFT analysis
AU - Agarwala, Hemlata
AU - Das, Dipanwita
AU - Mobin, Shaikh M.
AU - Mondal, Tapan Kumar
AU - Lahiri, Goutam Kumar
PY - 2011/8/1
Y1 - 2011/8/1
N2 - The ruthenium-iminoquinone complexes, [Ru(tpm)(Cl)(Q)]+ [tpm = tris(1-pyrazolyl)methane, Q = 3,5-di-tert-butyl-N-aryl-1,2- benzoquinonemonoimine, where aryl = C6H5, [1]+; m-(OCH3)2C6H3, [2]+; m-(Cl)2C6H3, [3]+] have been synthesized. The sensitive bond distances of "Q" in [1](ClO 4) and [2](ClO4), C-O: 1.294(8), 1.281(2) ; C-N: 1.352(8), 1.335(2) ; and C-C(meta): 1.366(10)/1.367(9) , 1.364(2)/1.353(2) , respectively, and other analytical as well as theoretical (DFT) events suggest the valence configuration of [RuIII(tpm)(Cl)(QSq ̇-)]+ for [1]+-[3]+. The paramagnetic [1]+-[3]+ show sharp 1H NMR spectra with strikingly small J of 1.8-3.0 Hz. The DFT calculations on [1] + predict that the triplet (S = 1) state exists above (1004 cm -1) the singlet (S = 0) ground state. [1]+ exhibits μ = 2.2 BM at 300 K which diminishes to 0.3 BM near 2 K due to the steady decrease in the ratio of triplet to singlet population with the lowering of temperature. [1]+-[3]+ exhibit one oxidation and two successive reductions each in CH3CN. Experimental and DFT analyses collectively establish the valence configurations at the non-innocent {Ru-Q} interface along the redox chain as [(tpm)(Cl)RuIII(QQo)] 2+ ([1]2+-[3]2+) → [(tpm)(Cl)Ru III(QSq̇-)]+ ([1]+-[3]+) → [(tpm)(Cl)RuII(Q Sq̇-)] ↔ [(tpm)(Cl)Ru III(QCat)] (1-3) → [(tpm)(Cl)RuII(Q Cat)]- ([1]--[3]-). The spectral features of [1]n-[3]n (n = +2, +1, 0) have been addressed based on the TD-DFT calculations on [1]n.
AB - The ruthenium-iminoquinone complexes, [Ru(tpm)(Cl)(Q)]+ [tpm = tris(1-pyrazolyl)methane, Q = 3,5-di-tert-butyl-N-aryl-1,2- benzoquinonemonoimine, where aryl = C6H5, [1]+; m-(OCH3)2C6H3, [2]+; m-(Cl)2C6H3, [3]+] have been synthesized. The sensitive bond distances of "Q" in [1](ClO 4) and [2](ClO4), C-O: 1.294(8), 1.281(2) ; C-N: 1.352(8), 1.335(2) ; and C-C(meta): 1.366(10)/1.367(9) , 1.364(2)/1.353(2) , respectively, and other analytical as well as theoretical (DFT) events suggest the valence configuration of [RuIII(tpm)(Cl)(QSq ̇-)]+ for [1]+-[3]+. The paramagnetic [1]+-[3]+ show sharp 1H NMR spectra with strikingly small J of 1.8-3.0 Hz. The DFT calculations on [1] + predict that the triplet (S = 1) state exists above (1004 cm -1) the singlet (S = 0) ground state. [1]+ exhibits μ = 2.2 BM at 300 K which diminishes to 0.3 BM near 2 K due to the steady decrease in the ratio of triplet to singlet population with the lowering of temperature. [1]+-[3]+ exhibit one oxidation and two successive reductions each in CH3CN. Experimental and DFT analyses collectively establish the valence configurations at the non-innocent {Ru-Q} interface along the redox chain as [(tpm)(Cl)RuIII(QQo)] 2+ ([1]2+-[3]2+) → [(tpm)(Cl)Ru III(QSq̇-)]+ ([1]+-[3]+) → [(tpm)(Cl)RuII(Q Sq̇-)] ↔ [(tpm)(Cl)Ru III(QCat)] (1-3) → [(tpm)(Cl)RuII(Q Cat)]- ([1]--[3]-). The spectral features of [1]n-[3]n (n = +2, +1, 0) have been addressed based on the TD-DFT calculations on [1]n.
KW - DFT
KW - Electrochemistry
KW - Iminoquinone
KW - Ruthenium
KW - Spectra
KW - Structure
UR - http://www.scopus.com/inward/record.url?scp=79960558436&partnerID=8YFLogxK
U2 - 10.1016/j.ica.2011.02.079
DO - 10.1016/j.ica.2011.02.079
M3 - Article
AN - SCOPUS:79960558436
SN - 0020-1693
VL - 374
SP - 216
EP - 225
JO - Inorganica Chimica Acta
JF - Inorganica Chimica Acta
IS - 1
ER -