Oxygen Of Carbonyl Group Research Articles

New metal-chelate complexes derived from the condensation product of biacetylmonoxime andN,N-dimethylglycine hydrazide hydrochloride (Girard's D Reagent)

The reactions between the condensation product of biacetylmonoxime andN,N-dimethylglycine hydrazide hydrochloride, [BMGD]Cl, and the hydrated NiII, CuII, CdII, HgII and UVIO2 salts give chelate complexes of types [M(BMGD)Cl2]Cl (M = CdII or HgII), [Cu(BMGD)2Br2]Cl2 and [M(BMGD-H)2(H2O)2]Cl2 · YH2O (M=NiII, CuII or UVIO2). Elemental analyses, magnetic measurements and spectra (i.r., visible, n.m.r.) have been used to characterize the complexes. I.r. spectral data show that the ligand is monodentate, coordiingvia the azomethine group of the hydrazone, or bidentate, coordinating through the azomethine and the carbonyl oxygen groups. The enolization of the carbonyl oxygen involves the NH rather than the CH2 group. The stereochemistry of the NiII and CuII complexes is discussed.

New Chelating Resins: 2-Hydroxy-4-methoxyacetophenone-Formaldehyde and 2-Hydroxy-4-methoxyacetophenone Oxime-Formaldehyde

Abstract This paper describes the syntheses and characterization of chelating resins, 2-hydroxy-4-methoxyacetophenone-formaldehyde (I) and 2-hydroxy-4-methoxyacetophenone oxime-formaldehyde (II). The number-average molecular weights have been determined by vapor pressure osmometry and nonaqueous conductometric titration methods. Metal chelates of the resins with Co(II), Ni(II) and Cu(II) were prepared. Elemental analysis of the chelates indicates a metal-to-ligand ratio of 1:2. The diffuse reflectance spectra and magnetic moments of Ni(II) and Co(II) chelates show a tetrahedral structure whereas Cu(II) chelate shows a square planar structure. Infrared spectral study show that the metal ions are coordinated through the oxygen of carbonyl group in I or nitrogen of the oximino group in II, and through the oxygen of the phenolic hydroxyl group. The presence of methylene bridges in the resins is also indicated by IR spectral studies.

The geometrical structures of the substituted oxiranes

The oxiranecarbaldehydes exist as single conformers in solution. The carbonyl group is rotated out of the plane of the bisector of the oxide ring by some 40°, the carbonyl-group oxygen being thereby separated from the oxide-ring oxygen. This conformation is favored from the standpoint of dipole-dipole interactions.

Rare Earth Complexes of 1-(2-Pyridylazo)-2-naphthol

Abstract The rare earth complexes of 1-(2-pyridylazo)-2-naphthol (PAN=Hpan) are prepared in the solid state. The analytical, molecular weight and differential thermal analysis data of the complexes indicated the metal-ligand ratio as 1:3 with the general formulae Ln(pan)3·H2O (Ln=Pr3+, Nd3+, and Sm3+) and Ln(pan)3 (Ln=La3+, Eu3+, Gd3+, Tb3+, Dy3+, Ho3+, Er3+, and Yb3+). Based on IR, UV, and visible absorption spectra, electrical conductance and magnetic susceptibility data, an octahedral structure having the metal ion bonded through nitrogen of azo and oxygen of carbonyl groups of the ligand has been postulated to these complexes.

Über die Infrarotspektren einiger Metallkomplexe des Mono- und Dimethylolharnstoffes

Coordination products of mono- and dimethyl-urea were synthesised with salts of copper, manganese, cobalt, nickel, and zink and their infrared spectra were obtained. By comparison with the pure ligands spectra it was established that the coordination with metals is accomplished through the carbonyl group oxygen.

Trimethylsilyl and diethylboron derivatives of ethyl N-nitrocarbamate

The trimethylsilyl and diethylboron derivatives of ethyl-N-nitrocarbamate were prepared. The former compound was found to exist as an equilibrium mixture of three stereoisomers, i.e., the N- and O-derivatives together with the previously unknown “imide” isomer. A mechanism of the tautomeric rearrangements in the system, involving both the charged ring intramolecular and the dissociative migration of the Si(CH3)3 group is suggested. The latter compound appears to exist in its “imide” form in which the boron atom is coordinated to the carbonyl group oxygen. The pyridine complex of this derivative has the N-isomer structure.

Hydrolysis of ethyl isovalerate in aqueous hydrochloric and sulfuric acid solutions

1. Effective rate constants (kef) for the hydrolysis of ethyl isovalerate in aqueous solutions containing from 4.95 to 41.3 mass % HCl, or from 2.52 to 94.0 mass % H2SO4, have been determined spectrophotometrically at 25°C. 2. The quantity kef increases with increasing acid concentration in aqueous HCl solutions. In aqueous sulfuric acid solutions, kef passes through a maximum at 49.8–55.9% H2SO4 and a minimum at 74.9% H2SO4. 3. In the hydrochloric acid and sulfuric acid solutions in question here (up to 74.9% H2SO4), the hydrolysis of ethyl isovalerate proceeds through an activated complex containing one un-ionized ester molecule and one hydronium ion carrying at least one solvation water molecule. The water molecule functions here as a nucleophilic agent. 4. The data obtained can be interpreted quantitatively by assuming that ionizatioa results in the formation of a protonized form of the ester and an unreactive complex in which the carbonyl group oxygen is bound to the hydronium ion. 5. Hydrolysis proceeds through the protonized form of the ester in sulfuric acid solutions with concentrations in excess of 74.9%.

Spectroscopic investigation of ion-molecule interactions in polymer solutions

The interaction between a number of inorganic salts and polyvinyl acetate (PVAc), a vinyl alcohol-vinyl acetate copolymer (VA-VAc) and polyvinyl alcohol (PVA) has been studied. It has been shown that, when perchlorates are introduced into solutions of PVAc or the VA-VAc copolymer in acetonitrile, the cation of the salt forms a donor-acceptor bond with the oxygen of hydroxyl and carbonyl groups of the polymers. When iodides are dissolved, in addition to these interactions, H bonds are formed in which the salt's anion and hydroxyl groups of the polymer participate. Possible types of transverse bonds between macromolecules in the gel forming systems studied are put forward; the role of the electrolyte in the formation of these bonds is explained.

Microwave spectrum, conformation, barrier to internal rotation and dipole moment of pyruvic acid

Microwave spectra of CH 3COCOOH and CH 3COCOOD are reported. The preferred conformation of the molecule is demonstrated to possess a planar HCCOCOOH skeleton with two out-of-plane hydrogens. The two carbonyl groups are trans to each other and a weak five-membered hydrogen bond is formed between the carboxyl group hydrogen atom and the carbonyl group oxygen atom. The methyl group conformation is discussed. A computer programme based on “the principal axis method” is described in some detail and the results of a least squares analysis of the observed spectra are outlined. The barrier to internal rotation was determined as V 3 = 965±40 cal mol −1 for both isotopic species. Stark effect measurements yielded μ a = 2.27±0.02 D, μ b = 0.35±0.02 D and μ tot = 2.30±0.03 D for the dipole moment and its components along the principal axes.