Determination of enantiomeric excess of leucine and valine by X-ray powder diffraction

Two amino acids, leucine and valine, were studied by X-ray powder diffraction (XRPD). The linear correlations between intensity of racemate (decrease) or enantiomer (increase) and enantiomeric excesses were observed in each case

Supplementary data for the article: Adhikary, J.; Chakraborty, A.; Dasgupta, S.; Chattopadhyay, S. K.; Kruszynski, R.; Trzesowska-Kruszynska, A.; Stepanović, S.; Gruden-Pavlović, M.; Swart, M.; Das, D. Unique Mononuclear Mn II Complexes of an End-off Compartmental Schiff Base Ligand: Experimental and Theoretical Studies on Their Bio-Relevant Catalytic Promiscuity. Dalton Transactions 2016, 45 (31), 12409–12422. https://doi.org/10.1039/c6dt00625f

Supplementary material: [https://doi.org/10.1039/c6dt00625f]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2294

Unique mononuclear Mn-II complexes of an end-off compartmental Schiff base ligand: experimental and theoretical studies on their bio-relevant catalytic promiscuity

Three new mononuclear manganese(II) complexes, namely [Mn(HL)(2)]center dot 2ClO(4) (1), [Mn(HL)(N(CN)(2)) (H2O)(2)]center dot ClO4 (2) and [Mn(HL)(SCN)(2)] (3) [LH = 4-tert-butyl-2,6-bis-[(2-pyridin-2-yl-ethylimino)-methyl]-phenol], have been synthesized and structurally characterized. An "end-off" compartmental ligand (LH) possesses two symmetrical compartments with N2O binding sites but accommodates only one manganese atom instead of two due to the protonation of the imine nitrogen of one compartment. Although all three complexes are mononuclear, complex 1 is unique as it has a 1 : 2 metal to ligand stoichiometry. The catalytic promiscuity of complexes 1-3 in terms of two different bio-relevant catalytic activities namely catecholase and phenoxazinone synthase has been thoroughly investigated. EPR and cyclic voltametric studies reveal that radical formation rather than metal centered redox participation is responsible for their catecholase-like and phenoxazinone synthase-like catalytic activity. A computational approach suggests that imine bond bound radical generation rather than phenoxo radical formation is most likely responsible for the oxidizing properties of the complexes.Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/3657

On construction of lead coordination polymers derived from <i>N</i>′-(2-hydroxybenzylidene)nicotinohydrazide via covalent and non-covalent interactions

<div><p>Lead(II) and lead(IV) coordination polymers with <i>N</i>′-(2-hydroxybenzylidene)nicotinohydrazide have been synthesized from lead(II) salts, and subsequently characterized by solid-state UV‒Vis‒IR spectroscopy, thermal analysis, and powder and single-crystal X-ray diffraction techniques. The compounds crystallize in the same space group but differ in the oxidation state of lead, composition, conformation of the organic ligand, its charge, and tautomeric form. The coordination network is propagated by the hydrazone anion in the lead(II) metal-organic framework <i>catena</i>-[(<i>μ</i>₂-<i>N</i>-((2-oxidophenyl)methylidene)pyridine-3-carbohydrazonoato-<i>N</i>:<i>N</i>′,<i>O</i>,<i>O</i>′)-lead(II) (<b>1</b>) and by nitrate in a one-dimensional lead(IV) coordination polymer <i>catena</i>-(<i>μ</i>₂-nitrato-O,O)-(nitrato-O,O′)-(salicylaldehydeisonicotinoylhydrazonato-N,N′,O)-lead(IV) nitrate (<b>2</b>). The formation of metal-organic framework of <b>1</b> is affected by Pb···<i>π</i> interactions.</p></div