02297nas a2200289   4500008004100000022001400041245009400055210006900149260007300218300001200291490000900303520131100312653002101623653001901644653001401663653002301677653001601700653001701716100002101733700002201754700001701776700001901793700002301812700002601835700002701861856011901888       2013                        eng d  a0022-286000aSynthesis and molecular structure of a zinc complex of the vitamin K-3 analogue phthiocol0 aSynthesis and molecular structure of a zinc complex of the vitam  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcSEP  a223-2290 v10483 a<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 `trans, trans' 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>10ahydrogen bonding10aNaphthoquinone10aPhthiocol10aTrans coordination10aVitamin K-310aZinc complex1 aKathawate, Laxmi1 aSproules, Stephen1 aPawar, Omkar1 aMarkad, Ganesh1 aHaram, Santosh, K.1 aPuranik, Vedavati, G.1 aSalunke-Gawali, Sunita  uhttps://library.ncl.res.in/content/synthesis-and-molecular-structure-zinc-complex-vitamin-k-3-analogue-phthiocol-002519nas a2200301   4500008004100000022001400041245012600055210006900181260007300250300001100323490000900334520145600343653000601799653001601805653002101821653002401842653002101866653002101887653001901908100002701927700001701954700002001971700002101991700002602012700002602038700002802064856012502092       2014                        eng d  a0022-286000aSynthesis, characterization and molecular structures of homologated analogs of 2-bromo-3-(n-alkylamino)-1,4-napthoquinone0 aSynthesis characterization and molecular structures of homologat  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcJAN  a97-1030 v10563 a<p>Four analogues of 2-bromo-3-(n-alkylamino)-1,4-napthoquinone (where n-alkyl is methyl in L-1Br, ethyl in L-2Br, propyl in L-3Br and butyl in L-4Br) are synthesized and characterized. A reaction mechanism is proposed for the formation of L-1 Br to L-4Br from the starting material 2,3-dibromo-1,4-naphthoquinone. The v(N-H) frequency in the FT-IR spectra is affected by the intramolecular hydrogen bonding in L-1Br to L-4Br and is observed similar to 3267 cm(-1) in L-2Br. A shift of similar to 25 cm(-1) is observed in the v(C-Br) frequency in all the compounds as compared to 2,3-dibromo-1,4-naphthoquinone (627 cm(-1)). A broad charge transfer band is observed between 400 and 600 nm in the UV-Vis spectra, which imparts red colour to all the compounds. Molecular structures of L-2Br and L-3Br were studied by single crystal X-ray diffraction studies. Molecules of L-2Br crystallize in Pca2(1), whereas the molecule L-3Br crystallizes in the P-1 space group. Molecules of L-2Br forms a polymeric chain through N-H...O interaction and forms beautiful butterfly like arrangement of molecules when viewed down the `a' axis. Ladder like polymeric chain of molecules is observed in L-3Br via C-H...O and N-H...O interactions. Every alternating neighbouring chains of L-3Br, show pi-pi stacking interactions between the quinonoid rings of the molecules, however this interaction is not observed in L-2Br. (C) 2013 Elsevier B.V. All rights reserved.</p>10a210a3-Dibromo-110a4-naphthoquinone10aAminonaphthoquinone10ahydrogen bonding10aMichael addition10api-pi stacking1 aSalunke-Gawali, Sunita1 aPawar, Omkar1 aNikalje, Milind1 aPatil, Rishikesh1 aWeyhermueller, Thomas1 aPuranik, Vedavati, G.1 aKonkimalla, Badireenath  uhttps://library.ncl.res.in/content/synthesis-characterization-and-molecular-structures-homologated-analogs-2-bromo-3-n-0