03127nas a2200313   4500008004100000022001400041245016800055210006900223260007600292300001600368490000700384520196100391653002402352653001302376653001402389653002802403653002602431653003202457100002102489700002102510700001802531700002602549700001702575700002702592700002802619700001902647700002602666856012102692       2008                        eng d  a0947-653900aValence-state analysis through spectroelectrochemistry in a series of quinonoid-bridged diruthenium complexes [(acac)(2)Ru(mu-L)Ru(acac)(2)](n) (n =+2,+1, 0,-1,-2)0 aValencestate analysis through spectroelectrochemistry in a serie  aCOMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USAbWILEY-BLACKWELLcOCT  a10816-108280 v143 a<p>The quinonoid ligand-bridged diruthenium compounds [(acac)(2)Ru(mu-L2-)Ru(acac)(2)] (acac(-) = acetylacetonato = 2,4-pentanedionato; L2- = 2,5-dioxido-1,4-benzoquinone, 1; 3,6-dichloro-2,5-dioxido-1,4-benzoquinone, 2; 5,8-dioxido-1,4-naphthoquinone, 3; 2-3-dichloro-5,8-dioxido-1,4-naphthoquinone, 4; 1,5-dioxido-9,10-anthraquinone, 5; and 1,5-diimido-9,10-anthraquinone, 6) were prepared and characterized analytically. The crystal structure analysis of 5 in the rac configuration reveals two tris(2,4-pentanedionato)ruthenium moieties with an extended anthracenedione-derived bis(ketoenolatee) pi-conjugated bridging ligand. The weakly antiferro-magnetically coupled {Ru-III(mu-L2-)Ru–(III)} configuration in 1-6 exhibits complicated overall magnetic and EPR responses,. ne simultaneous presence of highly redox-active quinonoid-bridging ligands and of two ruthenium centers capable of adopting the oxidation states +2, +3, and +4 creates a large variety of possible oxidation state combinations. Accordingly. the complexes 1-6 exhibit two reversible one-electron oxidation steps and at least two reversible reduction processes. Shifts to positive potentials were observed on introduction of Cl substituents (1 -&gt; 2, 3 -&gt; 4) or through replacement of NH by O (6 -&gt; 5). The ligand-to-metal charge transfer (LMCT) absorptions in the visible region of the neutral molecules become more intense and shifted to lower energies on stepwise reduction with two electrons. On oxidation, the para-substituted systems 1-4 exhibit monocation intermediates with intervalence charge transfer (IVCT) transitions of (RuRuIV)-Ru-III mixed-valent species. In contrast, the differently substituted systems 5 and 6 show no such near infrared (NIR) absorption. While the first reduction steps are thus assigned to largely ligand-centered processes, the oxidation appears to involve metal-ligand delocalized molecular orbitals with variable degrees of mixing.</p>10amagnetic properties10aquinones10aruthenium10aspectroelectrochemistry10astructure elucidation10avalence-state distributions1 aGhumaan, Sandeep1 aSarkar, Biprajit1 aMaji, Somnath1 aPuranik, Vedavati, G.1 aFiedler, Jan1 aUrbanos, Francisco, A.1 aJimenez-Aparicio, Reyes1 aKaim, Wolfgang1 aLahiri, Goutam, Kumar  uhttps://library.ncl.res.in/content/valence-state-analysis-through-spectroelectrochemistry-series-quinonoid-bridged-001717nas a2200205   4500008004100000022001300041245012200054210006900176260000800245300001400253490000700267520097300274100001701247700002101264700001901285700002501304700002601329700002401355856013201379       2018                        eng d  a1144054600aVanadium-based polyoxometalate complex as a new and efficient catalyst for phenol hydroxylation under mild conditions0 aVanadiumbased polyoxometalate complex as a new and efficient cat  cAPR  a5142-51520 v423 a<p>An eco-compatible catalytic protocol for H2O2 induced hydroxylation of phenol (PH) to catechol (CT) and hydroquinone (HQ) in aqueous medium, using a polyoxovanadate (POV) complex as the catalyst, is described. The synthesis of the POV catalyst, with a new type of three dimensional framework, Na6(H2O)22(V10O28)2H2O (1) was accomplished by establishing a non-hydrothermal one-step methodology under mild conditions. The catalyst was characterized by elemental analysis, spectral studies, single crystal X-ray diffraction studies, and Brunauer–Emmett–Teller (BET) and TGA analysis. Under optimum conditions of reaction, conducted at ambient temperature, the phenol conversion reached up to 55.4% providing a TON of 138. The catalyst could be recovered easily and recycled at least up to three cycles without significant change in activity. The developed methodology is operationally simple and free from halogenated solvents or any other hazardous additives.</p>1 aSharma, Mitu1 aSaikia, Gangutri1 aAhmed, Kabirun1 aGogoi, Sandhya, Rani1 aPuranik, Vedavati, G.1 aIslam, Nashreen, S.  uhttps://library.ncl.res.in/content/vanadium-based-polyoxometalate-complex-new-and-efficient-catalyst-phenol-hydroxylation-under