@article {UGC-New Delhi},
	title = {Single crystal X-ray structure of lawsone anion: evidence for coordination of alkali metal ions and formation of naphthosemiquinone radical in basic media},
	journal = {Journal of Molecular Structure},
	volume = {1010},
	number = {3-4},
	year = {2012},
	month = {FEB},
	pages = {38-45},
	publisher = {ELSEVIER SCIENCE BV},
	address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS},
	abstract = {<p>2-hydroxy-1,4-naphthoquinone; Lawsone (Lw) is a natural compound found in henna leaves. The reaction of lawsone with {\textquoteleft}Na{\textquoteright} metal (Lw-1), CH3COONa (Lw-2), NaOH (Lw-3), KOH (Lw-4), K2CO3 (Lw-5) and Tris(hydroxymethyl)aminomethane (Lw-6) were studied. Red orange solids obtained for Lw-1 to Lw-6 are characterized by Elemental Analysis, FTIR, (HNMR)-H-1 and EPR studies. The results reveal the coordination of alkali metals {\textquoteleft}Na{\textquoteright} and {\textquoteleft}K{\textquoteright} to lawsone anion. The single crystal X-ray structure of Lw-6 was solved and it crystallizes in triclinic space group P-1 with extensive hydrogen bonding network of C-H center dot center dot center dot O, N-H center dot center dot center dot O and O-H center dot center dot center dot O between cations and anions. Polycrystalline powder X-band EPR spectra of Lw-1 to Lw-5 shows signals similar to 2.004 at 133 K, while Lw-6 is EPR silent. The naphthosemiquinone (NSQ) radical formed in Lw-2 to Lw-5, is due to disproportion reaction of catechol and naphthoquinone. (C) 2011 Elsevier B.V. All rights reserved.</p>},
	keywords = {2-Hydroxy-1, 4-naphthoquione, EPR, hydrogen bonding, Lawsone, Naphthosemiquinone radicals},
	issn = {0022-2860},
	doi = {10.1016/j.molstruc.2011.11.015},
	author = {Salunke-Gawali, Sunita and Kathawate, Laxmi and Shinde, Yogesh and Puranik, Vedavati G. and Weyhermueller, Thomas}
}
@article { ISI:000323468500032,
	title = {Synthesis and molecular structure of a zinc complex of the vitamin K-3 analogue phthiocol},
	journal = {Journal of Molecular Structure},
	volume = {1048},
	year = {2013},
	month = {SEP},
	pages = {223-229},
	publisher = {ELSEVIER SCIENCE BV},
	address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS},
	abstract = {<p>The complex [Zn(phthiocol)(2)(H2O)(2)]; 1, where phthiocol is 2-hydroxy-3-methyl-1,4-naphthoquinone, has been synthesized and characterized by elemental analysis, FT-IR, H-1 NMR, UV-vis spectroscopy, thermogravimetric (TG) analysis, electrochemical and single crystal X-ray diffraction studies. The v(C=O) stretch shifts to lower frequencies upon complexation of phthiocol to Zn2+. H-1 NMR spectra show an upfield shift of the benzenoid ring protons in 1. There is a bathochromic shift of the LMCT band in the UV-vis spectra of 1. Single crystal X-ray structure of 1 show distorted octahedral geometry around Zn2+. Two phthiocol ligands are in plane with the metal, while water molecules are trans to this plane. Coordination of deprotonated phthiocol ligands is {\textquoteleft}trans, trans{\textquoteright} to Zn2+. Intra as well as intermolecular interactions are observed in 1. Molecules of 1 show three dimensional network through C-H center dot center dot center dot O and O-H center dot center dot center dot O interactions. Additional anodic peaks are observed in cyclic voltammogram of phthiocol ligand due to oxidation of reduced species formed during reduction. One-electron reduction of 1 is shown to be reversible and DFT studies define this redox event as ligand-centered. (c) 2013 Elsevier B.V. All rights reserved.</p>},
	keywords = {hydrogen bonding, Naphthoquinone, Phthiocol, Trans coordination, Vitamin K-3, Zinc complex},
	issn = {0022-2860},
	doi = {10.1016/j.molstruc.2013.05.057},
	author = {Kathawate, Laxmi and Sproules, Stephen and Pawar, Omkar and Markad, Ganesh and Haram, Santosh K. and Puranik, Vedavati G. and Salunke-Gawali, Sunita}
}
