Solvation of Yttrium with Ammonia:  An Experimental and Theoretical Study

Simard, Benoît; Rayner, D. M.; Bénichou, Emmanuel; Mireles, Norma; Tenorio, Francisco J.; Martı́nez, Ana

doi:10.1021/jp035871k

Cited by 9 publications

(9 citation statements)

References 14 publications

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“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] Of particular interest is the relationship between cluster and bulk surface chemistry. In this area, Mitchell et al 15 studied the reactions of copper and silver dimers with ammonia in the gas phase, while Chan and Fournier 17 reported a theoretical study of the binding of ammonia to small copper and silver clusters.…”

Section: Introductionmentioning

confidence: 99%

Bonding interactions of metal clusters [Mn (M= Cu, Ag, Au; n=1-4)] with ammonia. Are the metal clusters adequate as a model of surfaces?

Martínez¹

2005

J. Braz. Chem. Soc.

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Cálculos de densidade funcional (B3LYP/LANL2DZ) para clusters metálicos de amônia foram efetuados para obter comprimentos de ligação, modos de estiramento vibracional M-N, energias de ligação, cargas atômicas de Mulliken e potenciais adiabáticos de ionização. Os resultados indicam que átomos de cobre formam ligações mais intensas com amônia do que com prata ou ouro. A interação da ligação Ag n com amônia é a mais fraca de todos os sistemas. A ligação das moléculas de amônia à clusters metálicos é comparável à de sistemas piridina-M n. Ambas moléculas apresentam uma interação dativa do par de elétrons isolado no átomo de nitrogênio. Cargas atômicas de Mulliken mostram uma pequena transferência de carga da molécula NH 3 para o átomo metálico ou cluster, sugerindo a formação da ligação dativa. Depois da transferência de carga da molécula de amônia, os clusters metálicos sofrem uma redistribuição das cargas e isto pode ser importante na estabilização do sistema. Na superfície, a redistribuição de carga deve ser menos significativa. Nesse sentido, o uso de clusters metálicos como modelo de superfície pode ser um modelo inadequado.Density Functional (B3LYP/LANL2DZ) calculations for ammonia metal clusters were done in order to obtain bond lengths, M-N stretching vibrational modes, binding energies, Mulliken atomic charges and adiabatic ionization potentials. The results indicate that copper atom forms stronger bonds with ammonia than silver or gold. The bond interaction between Ag n and ammonia is the weakest of all the systems. The bond of the ammonia molecule to the metal clusters can be compared with the pyridine-M n systems. Both molecules present a donation interaction from the lone-pair of electrons on the nitrogen atom. Mulliken atomic charges show a small charge transfer from the NH 3 molecule to the metal atom or cluster, suggestive of a dative bond formation. After the charge transfer from the ammonia molecule, the metal clusters undergo a redistribution of the charge and this could be important for the stabilization of the system. In a surface, the redistribution of the charge should be less significant. In this sense, the use of metal clusters as a model of the surface may be an inadequate model. Keywords: metal clusters, bond lengths, M-N stretching vibrational modes, binding energies, Mulliken atomic charges and adiabatic ionization potentials IntroductionComplexes of bare metal clusters with simple molecules are important model systems for fundamental studies of metal-ligand bonding in cluster and surface chemistry. 1-17Of particular interest is the relationship between cluster and bulk surface chemistry. In this area, Mitchell et al. 15 studied the reactions of copper and silver dimers with ammonia in the gas phase, while Chan and Fournier 17 reported a theoretical study of the binding of ammonia to small copper and silver clusters. A simple picture of the bonding mechanism was reported, and comparisons were made between ammonia adsorbed on the metal atoms and on bulk surfaces.The theoretical study...

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Section: Introductionmentioning

confidence: 99%

Bonding interactions of metal clusters [Mn (M= Cu, Ag, Au; n=1-4)] with ammonia. Are the metal clusters adequate as a model of surfaces?

Martínez¹

2005

J. Braz. Chem. Soc.

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“…Figure 1A shows the optimized geometries for the most stable structures that were considered and reported earlier. 1 In that study, the oxidative addition was considered as the reaction mechanism, followed by the sequential addition of three further NH 3 molecules to YNH. Kinetic modeling and DFT calculations (Figure 1A) on the stability of YNH(NH) x imide complexes were consistent with a mechanism involving the solvation of yttrium imide by molecular NH 3 .…”

Section: Resultsmentioning

confidence: 99%

“…Kinetic modeling and DFT calculations (Figure 1A) on the stability of YNH(NH) x imide complexes were consistent with a mechanism involving the solvation of yttrium imide by molecular NH 3 . 1 However, this interpretation is brought into question by these new DFT results, that reveal evidence that absorption of NH 3 on YNH is dissociative to form Y(NH 2 ) 2 and that these di-amide species can adsorb molecularly additional NH 3 molecules to form Y(NH 2 ) 2 NH 3 , Y(NH 2 ) 2 (NH 3 ) 2 , and Y(NH 2 ) 2 (NH 3 ) 3 . The new structures for these compounds are shown in Figure 1B.…”

Section: Resultsmentioning

confidence: 99%

“…Figure A shows the optimized geometries for the most stable structures that were considered and reported earlier . In that study, the oxidative addition was considered as the reaction mechanism, followed by the sequential addition of three further NH 3 molecules to YNH.…”

Section: Resultsmentioning

confidence: 99%

“…The reactivity of transition metal−ligand complexes is an important research field. Many reports have focused on the electronic structure and the reaction mechanism for these transcendental systems. − Understanding the nature of the bonding in transition metal compounds is a topic of great interest, and remarkable progress has been made in the past years . In general, the transition metal−ligand bond is well described with the scheme of ligand donation and transition metal back-donation.…”

Section: Introductionmentioning

confidence: 99%

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Solvation of Yttrium with Ammonia Revisited. Di-amide Formation in the Reaction of Yttrium with Ammonia

Martı́nez

2006

J. Phys. Chem. A

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The reactivity of yttrium atoms toward ammonia is revisited using expanded density functional theory calculations. The new results reveal that absorption of NH3 on YNH is dissociative to form Y(NH2)2. The di-amide species can adsorb further NH3 molecules molecularly to form Y(NH2)2NH3 and Y(NH2)2(NH3)2. The calculations aimed to reveal the detail of the potential energy curves between the imide and the di-amide forms. The Y(NH2)2(NH3)x species are more stable than those of YNH(NH3)x by more than 20 kcal/mol.

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