Some substituted urea and thiourea complexes of Co(II), Mn(II), and Cr(III)

Askalani, Pakinam; Bailey, R. A.

doi:10.1139/v69-368

Cited by 25 publications

(5 citation statements)

References 9 publications

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“…These parameters and the v, calculated values are reported in Table 4 and CrXb3-ions, using the "law of average environment" (26,27). Table 4 shows that Dq and B' values of the complexes are in very good agreement with the literature data for CrL3X3 derivatives containing chromium-oxygen bonds in the tmderivatives and chromium-nitrogen bonds in all the other complexes.…”

supporting

confidence: 69%

Study of the Reactions of Chromium(III) Halides and Heterocyclic Ligands Containing Group VA and VIA Donor Atoms

Preti¹,

Tosi²

1974

Can. J. Chem.

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C. PRETI and G. TOSI. Can. J. Chem. 52,2845Chem. 52, (1974. Complexes of thiomorpholin-3-one, thiomorpholin-3-thione, thiazolidine-2-thione, and thiazolidine-2-selenone with CrX,,nH,O (X = C1, Br, I) were prepared and characterized. On the basis of vibrational (conventional and far infrared) and electronic spectroscopy, magnetism and conductivity measurements, the structures of these complexes were identified. The bonding occurs through the oxygen in the complexes of thiomorpholin-3-one and through the nitrogen in all the remaining complexes. The complexes CrL,X, involve unidentate ligands, are neutral, monomeric, and hexacoordinate. Spectroscopic parameters for the complexes have been calculated and compared with similar chromophores containing CrN3X,, Cr0,X3, and CrS3X3 chromophores.

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supporting

confidence: 69%

Study of the Reactions of Chromium(III) Halides and Heterocyclic Ligands Containing Group VA and VIA Donor Atoms

Preti¹,

Tosi²

1974

Can. J. Chem.

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“…The samples were heated up to 1073 K at a heating rate of 10 deg/min. Compounds (Table 1) were prepared by methods described in the literature [6][7][8] and were analysed by standard methods for metal and chloride, with good agreement with the calculated values. When required, sulfur was determined as BaSO 4.…”

Section: Methodsmentioning

confidence: 98%

Kinetics and mechanism of thermal decomposition of cadmium(II) complexes with substituted thioureas

Chruscinska

Masłowska

1987

Journal of Thermal Analysis

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From the thermal decomposition curves of cadmium(II) complexes with substituted thioureas (methyl-, dimethyl-, ethyl-, diethyl-, butyl-, dibutyl-, phenyl-, diphenyl-, acetyl-and benzoylphenylthiourea), the kinetic parameters of the thermal decompositions of these complexes were determined and a decomposition mechanism was suggested. The following thermal stability sequence is given for the Cd(I1) complexes: complexes with alkylthioureas < complexes with phenylthioureas < complexes with acylthioureas.Systematic studies on chemical and physical changes brought about by heating in chemical compounds provide information on the mechanisms and steps of their decomposition, and permit determination of the kinetic parameters of the reactions [1][2][3].The metal compounds of thioureas comprise an extensive series of sulfur-bonded complexes. Thermal decomposition studies here have been concerned with a few nickel(II) thiourea compounds [4], and acetylthiourea complexes of molybdenum [5] and Cd(II) [6]. The thermal decompositions Of methylthiourea and dimethylthiourea complexes of several transition metals, and of cadmium complexes containing various thioureas, have been studied by thermogravimetry in air and in vacuum. In vacuum, the dimethylthiourea complexes decomposed to a mixture of metal chloride and sulfide. The organic products included dimethylthiourea, methyl isothiocyanate, HC1 and polymerized material. In air, intermediates were formed in which part of the organic ligand was retained, followed by complete decomposition to inorganic salts at higher temperatures. While the overall pattern of decomposition was generally similar to that of thiourea itself, coordination

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“…Ureas may act as ligands to transition metal systems 10 through the O-or the N-atoms: the h 1 -O, h 1 -N and h 2 -N,N¢ modes of bonding 11 have been demonstrated. [15][16][17] The renovated interest in metal complexes (Mn II , Co II , Ni II , Cu II , Zn II , lanthanides) with N,N¢-dimethylurea-DMU, O-bonded to the metal, was due to their ability to form supramolecular 2D structures. Metal complexes containing 2, 4, 6 molecules of urea itself, 10,12 either O-or N-bonded have been described and a rare example of a chelate h 2 -N,N¢ mode of bonding has recently been described.…”

Section: Introductionmentioning

confidence: 99%

“…13 Metal complexes in which urea bridges two metal centres have also been characterized 14 and substituted ureas or thioureas have intensively been studied. [15][16][17] The renovated interest in metal complexes (Mn II , Co II , Ni II , Cu II , Zn II , lanthanides) with N,N¢-dimethylurea-DMU, O-bonded to the metal, was due to their ability to form supramolecular 2D structures. 18 Despite such abundance of cases, very rare studies on the reactivity of co-ordinated ureas are available in the literature: Ti-urea complexes have been thermally decomposed to afford nanoparticles of TiO 2 , 19 while Ni II -urea complexes have been reported to show an urease-like action.…”

Section: Introductionmentioning

confidence: 99%

The solid state structure and reactivity of NbCl5·(N,N′-dicyclohexylurea) in solution: evidence for co-ordinated urea dehydration to the relevant carbodiimide

et al. 2010

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NbCl(5) x (N,N'-dicyclohexylurea) 1a owns a distorted octahedral structure due to intramolecular NH...Cl bonding. The unit cell contains four units which are intermolecularly NH...Cl and NH...N bonded. An extended intramolecular network of H-bonding (N-H...Cl, CH...Cl, CH...N) causes the 3D self assembling of the units. Upon addition of base, the HCl release from 1a is observed with the transfer to Nb of the O-atom of the carbonylic function of the starting urea which is converted into the relevant carbodiimide CyN=C=NCy 4. The latter is quantitatively released by adding an excess of NEt(3) at 308 K (py and DBU are less efficient) with formation of the known NbOCl(3)(NEt(3))(2), isolated in quantitative yield. Increasing the temperature leads to a loss in selectivity as the formed DCC undergoes further reactions. At 350 K, the isocyanate CyN=C=O has been isolated in 60% yield besides a mixture of Nb-complexes. DFT calculations have been coupled to IR and NMR experiments for characterizing possible reaction intermediates and the behaviour of 1a. Several other MCl(x) species (ScCl(3), YCl(3), LaCl(3), TiCl(4), TaCl(5), AlCl(3), SnCl(4)) have been shown to be able to co-ordinate DCU but not all of them promote the conversion of urea into DCC.

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Some substituted urea and thiourea complexes of Co(II), Mn(II), and Cr(III)

Cited by 25 publications

References 9 publications

Study of the Reactions of Chromium(III) Halides and Heterocyclic Ligands Containing Group VA and VIA Donor Atoms

Study of the Reactions of Chromium(III) Halides and Heterocyclic Ligands Containing Group VA and VIA Donor Atoms

Kinetics and mechanism of thermal decomposition of cadmium(II) complexes with substituted thioureas

The solid state structure and reactivity of NbCl5·(N,N′-dicyclohexylurea) in solution: evidence for co-ordinated urea dehydration to the relevant carbodiimide

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