Sparkle Model for the Calculation of Lanthanide Complexes:  AM1 Parameters for Eu(III), Gd(III), and Tb(III)

Freire, Ricardo O.; Rocha, Gerd B.; Simas, Alfredo M.

doi:10.1021/ic048530+

Cited by 136 publications

(210 citation statements)

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“…15 We also present some evidence that geometries obtained via Sparkle/PM3 calculations are indeed trustworthy.…”

Section: Introductionmentioning

confidence: 69%

“…In a recent paper we introduced Sparkle/AM1, 15 a new paradigm for semiempirical quantum chemical calculations on lanthanide complexes. In this model, when a lanthanide complex is calculated, the lanthanide is represented by a sparkle, whereas the ligands are modeled by AM1.…”

Section: Introductionmentioning

confidence: 99%

“…1640 was essentially the same as the one of our previous work. 15 Accordingly, we only used high quality crystallographic structures (R-factor < 5%) of complexes taken from the Cambridge Structural Database 2003 (CSD), [47][48][49] having found a total of 96 structures of complexes of Eu(III), 70 of Gd(III), and 42 of Tb(III). As training sets we used the same three subsets of 15 complexes each, already chosen for the parameterization of Sparkle/AM1 for the same ions.…”

mentioning

confidence: 99%

“…Recent research on lanthanide complexes has in fact indicated that Sparkle/AM1 coordination polyhedron geometries are comparable to, if not better than geometries obtained from the best contemporary ab-initio full geometry optimization calculations with effective core potentials. 25,26 Besides, Sparkle/AM1 calculations are hundreds of times faster, 15 and have been recently employed for the study of quantum yields of luminescence. [27][28][29][30][31][32][33][34] However, although AM1 generally produces satisfactory results and its trustworthiness has been extensively timetested, other semiempirical models may prove more advantageous for some particular applications.…”

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confidence: 99%

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Sparkle/PM3 for the modeling of europium(III), gadolinium(III), and terbium(III) complexes

Freire¹,

Rocha

Simas³

2009

J. Braz. Chem. Soc.

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O modelo Sparkle/PM3 é parametrizado para complexos de európio (III), gadolínio (III) e térbio (III). A validação do modelo foi realizada utilizando noventa e seis complexos de Eu(III), setenta complexos de Gd(III) e quarenta e dois complexos de Tb(III); todos a partir de estruturas cristalográficas de alta qualidade, com fator R < 5%. Os erros médios absolutos, obtidos com o modelo Sparkle/PM3, considerando todas as distâncias interatômicas do tipo lantanídeo-átomo ligante, foram 0,080 Å para Eu(III), 0,063 Å para Gd(III) e 0,070 Å para Tb(III). Estes valores médios são similares aos obtidos com o modelo Sparkle/AM1 (0,082 Å, 0,061 Å, e 0,068 Å, respectivamente). Além disso, a exatidão em reproduzir o poliedro de coordenação de complexos de Eu(III), Gd(III) e Tb(III) é similar à obtida utilizando métodos ab initio com potenciais efetivos de caroço. Finalmente, com o objetivo de avaliar se as geometrias preditas com o modelo Sparkle/PM3 são confiáveis, escolhemos um dos complexos de Eu(III), BAFZEO, para o qual geramos centenas de diferentes geometrias iniciais, onde variamos de forma aleatória as distâncias e ângulos entre os ligantes e o íon Eu(III). Em seguida, todas essas geometrias iniciais foram otimizadas usando o modelo Sparkle/PM3. Como resultado, observamos uma tendência significativa onde a geometria que apresentou o menor erro médio absoluto apresentou também a energia total mais baixa, o que reforça a validade do modelo Sparkle.The Sparkle/PM3 model is extended to europium(III), gadolinium(III), and terbium(III) complexes. The validation procedure was carried out using only high quality crystallographic structures, for a total of ninety-six Eu(III) complexes, seventy Gd(III) complexes, and forty-two Tb(III) complexes. The Sparkle/PM3 unsigned mean error, for all interatomic distances between the trivalent lanthanide ion and the ligand atoms of the first sphere of coordination, is: 0.080 Å for Eu(III); 0.063 Å for Gd(III); and 0.070 Å for Tb(III). These figures are similar to the Sparkle/AM1 ones of 0.082 Å, 0.061 Å, and 0.068 Å respectively, indicating they are all comparable parameterizations. Moreover, their accuracy is similar to what can be obtained by present-day ab initio effective core potential full geometry optimization calculations on such lanthanide complexes. Finally, we report a preliminary attempt to show that Sparkle/PM3 geometry predictions are reliable. For one of the Eu(III) complexes, BAFZEO, we created hundreds of different input geometries by randomly varying the distances and angles of the ligands to the central Eu(III) ion, which were all subsequently fully optimized. A significant trend was unveiled, indicating that more accurate local minima geometries cluster at lower total energies, thus reinforcing the validity of sparkle model calculations. Keywords:Sparkle model, AM1, PM3, lanthanide complexes, rare earth coordination compounds IntroductionLanthanide complexes of the trivalent ions of europium, gadolinium, and terbium display a wide range of applications, with newer one...

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“…15 We also present some evidence that geometries obtained via Sparkle/PM3 calculations are indeed trustworthy.…”

Section: Introductionmentioning

confidence: 69%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Sparkle/PM3 for the modeling of europium(III), gadolinium(III), and terbium(III) complexes

Freire¹,

Rocha

Simas³

2009

J. Braz. Chem. Soc.

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“…And indeed, the rather compact but energetically high-lying 4f orbitals are incontestably shielded from the environment by the more diffuse 5s and 5p closed shells. In quantum mechanical studies, this chemical inactivity translates into semiempirical models where the lanthanide cation is represented by a central model potential [2], or into ab initio methods resorting to pseudopotentials (PP) that include the 4f electrons within a frozen core [3,4].…”

Section: Introductionmentioning

confidence: 99%