02214nas a2200277 4500008004100000022001400041245010800055210006900163260007300232300001000305490000900315520124800324653001301572653000801585653002101593653002301614653001401637653001501651100002101666700002401687700002201711700002301733700002601756700002701782856012701809 2015 eng d a0022-286000aFirst naphthosemiquinone complex of K+ with vitamin K3 analog: experiment and density functional theory0 aFirst naphthosemiquinone complex of K with vitamin K3 analog exp aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcMAY a56-630 v10883 a
Synthesis and characterization of potassium complex of 2-hydroxy-3-methyl-1,4-naphthoquinone (phthiocol), the vitamin K3 analog, has been carried out using FT-IR, UV-Vis, H-1 and C-13 NMR, EPR, cyclic voltammetry and single crystal X-ray diffraction experiments combined with the density functional theory. It has been observed that naphthosemiquinone binds to two K+ ions extending the polymeric chain through bridging oxygens O(2) and O(3). The crystal network possesses hydrogen bonding interactions from coordinated water molecules showing water channels along the c-axis. C-13 NMR spectra revealed that the complexation of phthiocol with potassium ion engenders deshielding of C(2) signals, which appear at delta = similar to 14.6 ppm whereas those of C(3) exhibit up-field signals near delta similar to 6.9 ppm. These inferences are supported by the M06-2x based density functional theory. Electrochemical experiments further suggest that reduction of naphthosemiquinone results in only a cathodic peak from catechol. A triplet state arising from interactions between neighboring phthiocol anion lead to a half field signal at g = 4.1 in the polycrystalline X-band EPR spectra at 133 K. (C) 2015 Elsevier B.V. All rights reserved.
10aC-13 NMR10aDFT10ahydrogen bonding10aNaphthosemiquinone10aPhthiocol10aVitamin K31 aKathawate, Laxmi1 aGejji, Shridhar, P.1 aYeole, Sachin, D.1 aVerma, Prakash, L.1 aPuranik, Vedavati, G.1 aSalunke-Gawali, Sunita uhttp://library.ncl.res.in/content/first-naphthosemiquinone-complex-k-vitamin-k3-analog-experiment-and-density-functional-0