Molecular and crystal structures of N-methyl-N-nitro-2-chloroaniline

The crystal structure of N-methyl-N-nitro-2-chloroaniline is determined by X-ray diffraction [a = 9.218(2) Å, b = 12.593(3) Å, c = 14.510(2) Å, space group Pbca, and Z = 8]. The structure is solved by the direct method and refined in the anisotropic approximation to R = 0.0377. All hydrogen atoms are localized. The structural parameters obtained agree with the data of the ab initio quantum-chemical B3LYP/6-31G** calculations. The data obtained are compared with those for N-methyl-N-nitro-4-chloroaniline. Conclusions on the interaction of the functional groups in the molecule are drawn.     

Structural and Vibrational Studies of Sr2[W(CN)8]·10H2O

The crystal structure of distrontium octacyanotungstate decahydrate, Sr₂[W(CN)₈] · 10H₂O, was solved using X‐ray single crystal diffraction. The tungsten atom lies on a two fold axis. Eight cyanide anions create tetragonal antiprismatic coordination sphere of tungsten atom. The two edge‐sharing tetragonal antiprisms of [Sr(NC)₃(OH₂)₅], create a dimer, [Sr₂(CN)₆(H₂O)₆(μ‐H₂O)₂], which lies on the inversion center. One symmetry independent water molecule is located in a void of 40 Å³. Vibrational (FT‐IR and FT‐Raman spectroscopic) behavior of main structural units is discussed. It was spectroscopically confirmed that the geometry of [W(CN)₈]^4– anion is slightly distorted from that corresponding to “free” anion. The number of observed bands is significantly lower than that expected for C₂ point group.     

HSAB principle and nickel(II) ion reactivity towards 1-methyhydantoin

1-Methylhydantoin and its novel nickel(II) complex [Ni(H₂O)₄(1-mhyd)₂] were prepared and identified, by elemental analysis, single crystal X-ray determination and MS methods. In addition, the complex was characterized by spectroscopic (IR, UV-Vis), magnetic and thermal techniques. The ligand reveals an interesting supramolecular architecture with both classical and non-conventional extended HB bonding networks. All rings and chains formed due to this HB bonding are embedded into the undulated pattern. A single crystal X-ray diffraction analysis of the complex shows that the nickel ion is coordinated by deprotonated hydantoin and water ligands in a N₂O₄ tetragonal arrangement. In the [Ni(H₂O)₄(1-mhyd)₂] structure both inter and intramolecular hydrogen bonds are created with the participation of water molecules.The ESI-MS method confirmed mono-nuclearity of the complex while electronic spectroscopy proved the tetragonal and pseudooctahedral geometries around the metal ion in the solid state and solution, respectively. By application of the “average environment rule”, 10Dq parameters were obtained for the hypothetical, hexa-coordinate [Ni(1-mhyd)₆] approximation or rather more realistic [Ni(1-mhyd)₃] chelate. Based on this the mhyd ligand was ranked in the spectrochemical series close to ammonia. The general consideration of the structure of the hydantoin complexes as a function of the metal ion hardness within the framework of the HSAB theory has been provided. Both the ligand and the complex were found to be non-toxic agents against breast (MCF-7), lung carcinoma epithelial (A549) and mouse fibroblasts (Balb/3T3) cancer cell lines.     

DFT and experimental studies on structure and spectroscopic parameters of 3,6-diiodo-9-ethyl-9H-carbazole

Structural Chemistry - The first report on crystal and molecular structure of 3,6-diiodo-9-ethyl-9H-carbazole is presented. Experimental room-temperature X-ray and 13C chemical shift studies were...     

Different methods to select the best extraction system for solid‐phase extraction

The optimization methods for planning a solid‐phase extraction experiment are presented. These methods are based on a study of interactions between different parts of an extraction system. Determination of the type and strength of interaction depends on the physicochemical properties of the individual components of the system. The main parameters that determine the extraction properties are described in this work. The influence of sorbents’ and solvents’ polarity on extraction efficiency, Hansen solubility parameters and breakthrough volume determination on sorption and desorption extraction step are discussed.     

Rearrangement products of 3‐methane­sulfonyl‐N‐methyl‐N‐nitro­aniline

Two isomeric products (C₈H₁₀N₂O₄S) of the rearrangement of 3‐methane­sulfonyl‐N‐methyl‐N‐nitro­aniline have been investigated, viz. 3‐methane­sulfonyl‐N‐methyl‐2‐nitro­aniline, which was the main product of the rearrangement, and 5‐methane­sulfonyl‐N‐methyl‐2‐nitro­aniline. In both mol­ecules, the aromatic rings are appreciably deformed towards ortho‐quinonoidal geometry by electronic and steric interactions. The crystal structure is stabilized, in both cases, by weak C—H⋯O hydrogen bonds.     

Synthesis, X-ray structure, and spectroscopic investigation of new Co(II)/Cd(II) complexes formed via the reaction of 1-hydroxymethyl-3,5-dimethylpyrazole and Co0, CdCl2, NH4I

The novel complex [Co(L)Cl]₂[CdI₄] obtained in situ from the redox system (Co⁰, CdCl₂, NH₄I, 1-hydroxymethyl-3,5-dimethylpyrazole) was characterized by X-ray diffraction IR, UV–VIS as well as magnetic and thermal investigations. The ligand, tris(1-(3,5-dimethylpyrazolylmethyl)amine (L) was synthesized in situ as a product of condensation 1-hydroxymethyl-3,5-dimethylpyrazole and ammonia molecule formed during redox process. The crystal structure of 1 includes in the unit cell two chemically identical but symmetry-independent cations: [Co(1)(L)Cl]⁺ and [Co(2)(L)Cl]⁺. Each of the [Co(L)Cl]⁺ complex ions has C₃ point group symmetry, but the point group symmetry of the trigonal bipyramidal coordination spheres of [CoN₃N′Cl] and tetrahedral sphere of [CdI₄] has C_3v point group symmetry.     

Synthesis, crystal structure, spectroscopic, magnetic, theoretical, and microbiological studies of a nickel(II) complex of L-tyrosine and imidazole, [Ni(Im)2(L-tyr)2]·4H2O

The [Ni(Im)(2)(L-tyr)(2)]·4H(2)O (1) complex was obtained in crystalline form as a product of interaction of L-tyrosine sodium salt, imidazole, and NiSO(4). The X-ray structure was determined, and the spectral (IR, FIR, NIR-vis-UV, HF EPR) and magnetic properties were studied. The Ni(2+) ion is hexacoordinated by the N and O atoms from two L-tyrosine molecules and by two N atoms of imidazole, resulting in a slightly distorted octahedral [NiN(2)N(2)'O(2)] geometry with a tetragonality parameter T = 0.995. The bands observed in the electronic spectra were ascribed to the six spin-allowed electronic transitions (3)B(1g) → (3)E(g) and (3)B(2g), (3)B(1g) → (3)A(2g) and (3)E(g), and (3)B(1g) → (3)A(2g) and (3)E(g). The spin Hamiltonian parameters g, D, and E, which were determined from high-field HF EPR spectra, excellently reproduced the magnetic properties of the complex. Calculation of the zero-field splitting in the S = 1 state of nickel(II) using DFT and UHF was attempted. The biological activity of the complexes has been tested for antifungal and antibacterial effects against Aspergillus flavus, Fusarium solani, Penicillium verrucosu, Bacillus subtilis, Serratia marcescens, Pseudomonas fluorescens, and Escherichia coli.