Infrared Absorption Spectra of Inorganic Coördination Complexes. X. Studies of Some Metal-Urea Complexes<sup>1a,b</sup>

Penland, R. B.; Mizushima, Shôji; Curran, Columba; Quagliano, J. V.

doi:10.1021/ja01564a014

Cited by 257 publications

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“…Figures 3(a)-3(d) shows SEM images of samples taken at different stages from a synthesis where the molar ratio of CTAB to MnSO 4 ·H 2 O was 3. When the hydrolysis took place at a temperature of 75 °C [32], only an amorphous morphology was apparent in the SEM images ( Fig. 3(a)).…”

Section: Resultsmentioning

confidence: 99%

Shape-controlled synthesis of Mn3O4 nanocrystals and their catalysis of the degradation of methylene blue

et al. 2010

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Various sizes and shapes of Mn 3 O 4 nanocrystals have been prepared in a one-pot synthesis in extremely dilute solution by soft template self-assembly. To better control size and shape, the effects of varying the growth time, reaction temperature, surfactant, and manganese source were examined. The average size of octahedral Mn 3 O 4 crystallites was found to be related to the reaction time, while higher reaction temperature (150 °C ) and the use of a cetyltrimethylammonium bromide/poly(vinylpyrrolidone) (CTAB/PVP) mixture allowed construction of a better-defined octahedral morphologies. When PVP or poly(ethylene oxide)-poly(propylene oxide) (P123) was used as template, large-scale agglomeration resulting in loss of the octahedral morphology occurred and crystallites with a quasi-spherical shape were obtained. The nano-octahedral crystallites were shown to be an efficient catalyst for the oxidation of methylene blue.

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Section: Resultsmentioning

confidence: 99%

Shape-controlled synthesis of Mn3O4 nanocrystals and their catalysis of the degradation of methylene blue

et al. 2010

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“…The double-bond oxygen of HyU may then form a weak hydrogen-type bond with hydroxyl or titanium atom of another cluster. This is schematically shown below: 38,39 In the first case, the nitrogen binding to a metal brings about increased CQO double bond character. 38 In contrast, in the second case the coordination increases the single bond character of the CQO group, moving the correspondent band to low energies; consequently, the C-N band moves to higher frequencies.…”

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confidence: 99%

TiO2 doping by hydroxyurea at the nucleation stage: towards a new photocatalyst in the visible spectral range

Azouani¹,

Tieng²,

Chhor³

et al. 2010

Phys. Chem. Chem. Phys.

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We report an original method of preparation of OCN-doped TiO 2 for photocatalysis in the visible spectral range. The preparation is achieved by a sol-gel route using titanium tetraisopropoxide precursor. Special attention was paid to fluid micromixing, which enables homogeneous reaction conditions in the reactor bulk and monodispersity of the produced clusters/nanoparticles. The dopant hydroxyurea (HyU, CH 4 N 2 O 2 ) is injected into the reactive fluid at the nucleation stage, which lasts tens of milliseconds. The doping results in a strong yellow coloration of the nanocolloids due to the absorption band in the spectral range 380-550 nm and accelerates the aggregation kinetics of both nuclei at the induction stage and sub-nuclei units (clusters) at the nucleation stage. FTIR, Raman and UV-visible absorption analyses show the formation of a stable HyU-TiO 2 complex. EXAFS spectra indicate no appreciable changes of the first-shell Ti atom environment. The doping agent takes available surface sites of TiO 2 clusters/ nanoparticles attaining B10% molar loading. The reaction kinetics then accelerates due to a longer collisional lifetime between nanoparticles induced by the formation of a weak QOÁ Á ÁTi bond. The OCN-group bonding to titanium atoms produces a weakening of the CQO double bond and a strengthening of the C-N and N-O bonds.

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“…It is expected that coordination affects the vibrational frequencies of urea, especially those of NH2 stretching and CO stretching vibrations. In fact, Penland et al 10) have found that dichloro(bisurea)platinum (II) and dichloro-(bisurea)palladium (II) show a decrease in the frequencies of NH2 stretchings and antisymmetric CN stretching as well as an increase in the frequencies of CO stretching coupled with NH2 scissoring and concluded that nitrogen is involved as donor atoms in coordination. On the other hand, Table IV shows that no marked differences can be found in the NH2 stretchings, the CO stretching mixed with the NH2 scissoring, the antisymmetric CN stretching, etc.…”

Section: Discussionmentioning

confidence: 99%

Infrared Spectra of Urea Complexes of Copper(II) n-Alkanoates

Kuroda¹,

Sasano²,

Kubo³

1966

Bulletin of the Chemical Society of Japan

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The infrared absorption spectra of various urea complexes of copper(II) carboxylates were recorded and the assignments of observed frequencies have been carried out to various modes of vibration. On the basis of comparison of the observed spectra with those of related compounds, it is concluded that copper(II) carboxylate monoureas and hemiureas form dimer molecules in crystals as in copper(II) acetate monohydrate, that copper(II) formate bisurea dihydrate has a crystal structure bearing resemblance to that of copper(II) formate tetrahydrate, and that urea molecules in these urea complexes are involved in bonding by electrostatic forces or hydrogen bondings instead of being bonded to copper atoms by coordination bonds.

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Infrared Absorption Spectra of Inorganic Coördination Complexes. X. Studies of Some Metal-Urea Complexes^1a,b

Cited by 257 publications

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Shape-controlled synthesis of Mn3O4 nanocrystals and their catalysis of the degradation of methylene blue

Shape-controlled synthesis of Mn3O4 nanocrystals and their catalysis of the degradation of methylene blue

TiO2 doping by hydroxyurea at the nucleation stage: towards a new photocatalyst in the visible spectral range

Infrared Spectra of Urea Complexes of Copper(II) n-Alkanoates

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Infrared Absorption Spectra of Inorganic Coördination Complexes. X. Studies of Some Metal-Urea Complexes1a,b

Cited by 257 publications

References 0 publications

Shape-controlled synthesis of Mn3O4 nanocrystals and their catalysis of the degradation of methylene blue

Shape-controlled synthesis of Mn3O4 nanocrystals and their catalysis of the degradation of methylene blue

TiO2 doping by hydroxyurea at the nucleation stage: towards a new photocatalyst in the visible spectral range

Infrared Spectra of Urea Complexes of Copper(II) n-Alkanoates

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Infrared Absorption Spectra of Inorganic Coördination Complexes. X. Studies of Some Metal-Urea Complexes^1a,b