@article { ISI:000351969900008,
	title = {First naphthosemiquinone complex of K+ with vitamin K3 analog: experiment and density functional theory},
	journal = {Journal of Molecular Structure},
	volume = {1088},
	year = {2015},
	month = {MAY},
	pages = {56-63},
	publisher = {ELSEVIER SCIENCE BV},
	address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS},
	abstract = {<p>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.</p>},
	keywords = {C-13 NMR, DFT, hydrogen bonding, Naphthosemiquinone, Phthiocol, Vitamin K3},
	issn = {0022-2860},
	doi = {10.1016/j.molstruc.2015.01.053},
	author = {Kathawate, Laxmi and Gejji, Shridhar P. and Yeole, Sachin D. and Verma, Prakash L. and Puranik, Vedavati G. and Salunke-Gawali, Sunita}
}
