Milan Melnik

Bio: Milan Melnik is an academic researcher from University of York. The author has contributed to research in topics: Copper & Crystal structure. The author has an hindex of 26, co-authored 219 publications receiving 2513 citations. Previous affiliations of Milan Melnik include York University & Slovak University of Technology in Bratislava.

Structural aspects of iron coordination compounds: i. monomeric derivatives

Abstract: This review summarises almost nine hundred crystallographic structures of monomelic iron coordination compounds. The number of examples per given oxidation state for the iron increases in the order: Fe(-II) (tetrahedral) < Fe(-I) (tetrahedral) < Fe(IV) (six coordinated and square pyramidal) < Fe(0) (five coordinated ) < Fe(I) (square pyramidal and square planar) < Fe(III) (three to seven coordinated) < Fe(II) (two to eight and ten coordinated). Variations and trends in bond lengths and angles are discussed.

Preparation, Structure, Spectral, and Magnetic Properties of Copper(II) Halogenonicotinates: Crystal and Molecular Structure of Tetrakis(μ-2-chloronicotinato-O,O′)-diaquadicopper(II)

Abstract: The characterization of the complexes [Cu2(2-Clnic)4(H2O)2] (1), [Cu(2,6-Cl2nic)2(H2O)2] (2) and [Cu(5-Brnic)2(H2O)2]n (3) (where 2-Clnic = 2-chloronicotinate, 2,6-Cl2nic = 2,6-dichloronicotinate or 5-Brnic = 5-bromonicotinate) was based on elemental analysis, IR, electronic and EPR spectra, and magnetic susceptibility. Complex 1 was also studied by X-ray analysis at 298 1a and 80 K 1b. The complex 1 contains a dinuclear Cu-acetate molecular structure in which the carboxyl groups of the 2-chloronicotinate ligands act as bridges and water molecules are at apical positions. The stereochemistry about Cu atom at both temperatures is typical for square pyramidal geometry with CuO4O chromophore. The Cu-Cu distance is 2.6513(8) and 2.6382(6) A for 1a and 1b, respectively. The Cu atoms are displaced by 0.2069(9) and 0.1973(7) A, respectively, from the plane containing four oxygen atoms bonded to the Cu atom toward the apical water molecules. Strong and weak hydrogen bonds as well as C–Cl···π interactions in the crystal structure are discussed as well. Both complexes, monomeric [Cu(2,6-Cl2nic)2(H2O)2] (2) and polymeric [Cu(5-Brnic)2(H2O)2]n (3), possess octahedral copper(II) stereochemistry with differing tetragonal distortions.

Thermal and spectral properties of Cu(II)-5-halogenosalicylates with or without nicotinamide

Abstract: This paper deals with the preparation and investigation of thermal and spectral properties of the complexes Cu(5-ClSal)2·2H2O (I), Cu(5-BrSal)2·2H2O (II), Cu(5-ClSal)2(nia)(H2O) (III), Cu(5-BrSal)2(nia)(H2O) (IV), and Cu(5-ISal)2(nia)(H2O) (V) (where Sal=salicylate, and nia=nicotinamide). TG, DTG, DTA, EPR, IR and electronic spectra have been used to study thermal and spectral properties of the complexes. The chemical composition of the complexes, the solid intermediates and the resultant products of thermolysis have been identified by means of elemental analysis and complexometric titration. Schemes of the decomposition of the complexes are suggested. Heating of the compounds first resulted in the release of water molecules. The thermal stability of these complexes can be ordered in the sequence: I

Shape‐Controlled Synthesis of Metal Nanocrystals: Simple Chemistry Meets Complex Physics?

Abstract: Nanocrystals are fundamental to modern science and technology. Mastery over the shape of a nanocrystal enables control of its properties and enhancement of its usefulness for a given application. Our aim is to present a comprehensive review of current research activities that center on the shape-controlled synthesis of metal nanocrystals. We begin with a brief introduction to nucleation and growth within the context of metal nanocrystal synthesis, followed by a discussion of the possible shapes that a metal nanocrystal might take under different conditions. We then focus on a variety of experimental parameters that have been explored to manipulate the nucleation and growth of metal nanocrystals in solution-phase syntheses in an effort to generate specific shapes. We then elaborate on these approaches by selecting examples in which there is already reasonable understanding for the observed shape control or at least the protocols have proven to be reproducible and controllable. Finally, we highlight a number of applications that have been enabled and/or enhanced by the shape-controlled synthesis of metal nanocrystals. We conclude this article with personal perspectives on the directions toward which future research in this field might take.