3-(2-Chloro­ethyl)-2-methyl-4H-pyrido[1,2-a]pyrimidin-4-one

In the title mol­ecule, C11H11ClN2O, the pyrido[1,2-a]pyrimidine ring system is planar (maximum deviation = 0.0148 Å) and the methyl C and carbonyl O atoms are nearly coplanar to it. The chloro­ethyl side chain is in a synclinal conformation, nearly orthogonal to the pyrimidine ring, with a dihedral angle between the chloro­ethyl side chain and the pyrimidine ring of 88.5 (1)°. Weak inter­molecular C—H⋯N and C—H⋯Cl hydrogen bonds along with π–π inter­actions between the pyrimidine and pyridine rings [centroid–centroid distance is 3.538 (2) Å] form a three-dimensional network. The crystal is a racemic twin with a 0.68 (12):0.32 (12) domain ratio. MOPAC AM1 and density functional theory (DFT) theoretical calculations at the B3-LYP/6–311+G(d,p) level support these observations

Syntheses, structures, and geometric and spectral characteristics of the hexachlorodicuprate(II) complexes with the protonated 4-azafluoren-9-one derivatives: The crystal and molecular structures of bis(4-azafluoren-9-onium) hexachlorodiaquadicuprate(II) dihydrate

Three complexes containing hexachlorodicuprate(II) anions and protonated 4-azafluorenone derivatives as counterions were isolated. The crystal and molecular structures of 4-azafluoren-9-one, (HL1) 2[(CuCl2(H2O))2(μ-Cl) 2] • 2H2O (L1), and spectral characteristics of the complexes were determined. Relationships relating the degree of distortion of the crystal structure of the hexachlorodicuprate(II) anions to the spectral characteristics of the compounds were proposed on the basis of the experimental and published data. © 2009 Pleiades Publishing, Ltd

Bis(1-amino-4-azafluoren-9-olium) and bis(2-amino-3-hydroxypyridinium) tetrachlorocobaltates(II): Crystal and molecular structure

Crystal and molecular structure and spectral characteristics are determined for bis(1-amino-4-azafluoren-9-olium) and bis(2-amino-3-hydroxypyridinium) tetrachlorocobaltates(II): CoCl4(C12H11N 2O)2 and CoCl4(C5H7N 2O)2, respectively. The structural units of the complexes are CoCl 4 2- anions and organic cations protonated at the pyridine nitrogen atom. © 2008 Pleiades Publishing, Ltd

Bis(1-amino-4-azafluoren-9-olium) and bis(2-amino-3-hydroxypyridinium) tetrachlorocobaltates(II): Crystal and molecular structure

Crystal and molecular structure and spectral characteristics are determined for bis(1-amino-4-azafluoren-9-olium) and bis(2-amino-3-hydroxypyridinium) tetrachlorocobaltates(II): CoCl4(C12H11N 2O)2 and CoCl4(C5H7N 2O)2, respectively. The structural units of the complexes are CoCl 4 2- anions and organic cations protonated at the pyridine nitrogen atom. © 2008 Pleiades Publishing, Ltd

Synthesis and physicochemical properties of some transition metal complexes with 3-hydroxypyridine

The complexes ML2·2H2O and CrL 3·8H2O were synthesized by the reaction of Cu(II), Ni(II), Co(II), Cd(II), and Cr(III) nitrates with 3-hydroxypyridine (HL) and identified. The spectroscopic characteristics of neutral, anionic, and cationic forms of the ligand were determined. It was shown that 3-hydroxypyridine enters the complex as an anion to give polymeric chains due to the ligand coordination through the N and O atoms. Complexation of copper, cobalt, and chromium nitrates with 3-hydroxypyridine in ethanol solutions was studied, and the formation constant of the copper complex was calculated. It was found that Cu(II) and Cr(III) complexes are formed in the solid state and in solutions (M: L = 1:2 and 1:3, respectively; in the case of Cu(II), the M:L ratio is 1:3)

Spectral characteristics and acid-base equilibria of 4,9-dihydroxy-5,10-dioxo-4,5,9,10-tetrahydro-4,9-diazapyrene and its 2,7-derivatives

The IR and electronic spectra of 2,7-disubstituted 4,9-dihydroxy-5,10-dioxo-4,5,9,10-tetrahydro-4,9-diazapyrene (R = H, I, NH2, NO2, OH) are studied. Analysis of the IR bands shows that, in crystalline form and in neutral and basic solutions, the compounds exist predominantly in the hydroxamic form. It is established that in sulfuric acid solutions the oxygen atoms of the C=O groups are protonated. The spectral characteristics of the neutral and ionized forms of the compounds are determined. The acid ionization constants are measured by potentiometric titration. © 1993 Plenum Publishing Corporation

Experimental and theoretical investigation of the structure and spectral characteristics of bis(4-aza-9-fluorenone)dibromocopper(II)

The molecular and crystal structure of bis(4-aza-9-fluorenone) dibromocopper(II) [CuL2Br2] was determined by X-ray diffraction. The organic molecule is coordinated in the monodentate fashion with participation of lone electron pairs of heterocyclic nitrogen atoms of 4-aza-9-fluorenone. The coordination unit parameters were calculated by DFT with PBE functional. The Cu-Br and Cu-N coordination bonds are covalent, the electron pairs of the ligand are transferred to the vacant orbitals of the central ion. The computational methods adequately reproduce the structure of the IR spectrum of the complex. © Pleiades Publishing, Ltd., 2010

Refinement of the Molecular Structure of Ammonium Pentachloroaquaferrate (NH₄)₂[FeCl₅(H₂O)]

The crystal structure of ammonium pentachloroaquaferrate (NH4)2[FeCl5(H2O)] is refined (CIF file CCDC no. 1831198). Compounds (А)х[FeCl5(H2O)], where A is an organic or inorganic anion (х = 1, 2), crystallize in the orthorhombic crystal system. The geometry and structural parameters of the [FeCl5(H2O)]2– anion are nearly independent of the counterion nature