Sparkle/AM1 Structure Modeling of Lanthanum (III) and Lutetium (III) Complexes

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

doi:10.1021/jp057286k

Cited by 30 publications

(37 citation statements)

References 22 publications

(46 reference statements)

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“…Figure 2 presents gamma distribution fits of the UME (Ln-L) data for lutetium for both the present Sparkle/PM3 and the previously published Sparkle/AM1 model. 3 In both cases, the respective p values were well above the critical value of 0.05, thus validating the use of both Lu(III) Sparkle models. Table 2 presents unsigned mean errors for both Sparkle/PM3 and Sparkle/AM1 for various types of distances in the La(III) and Lu(III) complexes considered.…”

Section: Resultssupporting

confidence: 56%

“…To give a simple pictorial idea of this concept and also of where and how the actual UME values occurred, Figure 1 also presents superimposed histograms of the data with the number of bars chosen to best adjust the histogram to the curve obtained from the gamma distribution fit. For comparison purposes, Figure 1b presents the same gamma distribution fit for the UME (La-L) data for the already published Sparkle/AM1 model for La(III), 3 which gives a p value of 0.905. Figure 2 presents gamma distribution fits of the UME (Ln-L) data for lutetium for both the present Sparkle/PM3 and the previously published Sparkle/AM1 model.…”

Section: Resultsmentioning

confidence: 97%

“…3 Figure 1a presents a gamma distribution fit of the UME (La-L) data for the Sparkle/PM3 model for La(III). As indicated in the figure, the p value is 0.655, thus indicating that the UME values are indeed significantly randomly distributed around the mean through a gamma distribution.…”

Section: Resultsmentioning

confidence: 99%

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Structure Modeling of Trivalent Lanthanum and Lutetium Complexes: Sparkle/PM3

et al. 2007

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The recently defined Sparkle model for the quantum chemical prediction of geometries of lanthanum(III) and lutetium(III) complexes within AM1 (J. Phys. Chem. A 2006, 110, 5897) has been extended to PM3. As training sets, we used the same two groups, one for each lanthanide, of 15 high-crystallographic-quality (R factor < 0.05 A) complexes as was previously chosen to parametrize Sparkle/AM1. Likewise, in the validation procedure, we used the same Sparkle/AM1 validation sets of 60 additional La(III) and 15 additional Lu(III) complexes. The Sparkle/PM3 unsigned mean errors for all interatomic distances between the metal ions and the ligand atoms of the first sphere of coordination proved to be random around the means of 0.068 A for lanthanum(III) and 0.076 A for lutetium(III), thus being comparable to the respective Sparkle/AM1 values of 0.078 and 0.075 A. Furthermore, effective-core-potential ab initio calculations on smaller subsets of such complexes led to similar accuracies. Sparkle/PM3 and Sparkle/AM1 are therefore made available to the researcher who must decide which of the models to use based on considerations of the impact of either PM3 or AM1 on the description of the ligands and the consequence of such a choice on the properties of interest.

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Section: Resultssupporting

confidence: 56%

Section: Resultsmentioning

confidence: 97%

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Structure Modeling of Trivalent Lanthanum and Lutetium Complexes: Sparkle/PM3

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“…The sparkle concept was then applied to alkaline and alkaline earth complexes as well. 38,39 Subsequently, the model was extended to all other lanthanide ions within AM1, 40–48 and was later parameterized for PM3 49–55 and for PM6. 56 In 2006, we published an article in which we compared Sparkle calculations with ab initio effective core potential calculations.…”

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confidence: 99%

Sparkle/PM7 Lanthanide Parameters for the Modeling of Complexes and Materials

Dutra

Filho

Rocha

et al. 2013

J. Chem. Theory Comput.

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The recently published Parametric Method number 7, PM7, is the first semiempirical method to be successfully tested by modeling crystal structures and heats of formation of solids. PM7 is thus also capable of producing results of useful accuracy for materials science, and constitutes a great improvement over its predecessor, PM6. In this article, we present Sparkle Model parameters to be used with PM7 that allow the prediction of geometries of metal complexes and materials which contain lanthanide trications. Accordingly, we considered the geometries of 224 high-quality crystallographic structures of complexes for the parameterization set and 395 more for the validation of the parameterization for the whole lanthanide series, from La(III) to Lu(III). The average unsigned error for Sparkle/PM7 for the distances between the metal ion and its coordinating atoms is 0.063Å for all lanthanides, ranging from a minimum of 0.052Å for Tb(III) to 0.088Å for Ce(III), comparable to the equivalent errors in the distances predicted by PM7 for other metals. These distance deviations follow a gamma distribution within a 95% level of confidence, signifying that they appear to be random around a mean, confirming that Sparkle/PM7 is a well-tempered method. We conclude by carrying out a Sparkle/PM7 full geometry optimization of two spatial groups of the same thulium-containing metal organic framework, with unit cells accommodating 376 atoms, of which 16 are Tm(III) cations; the optimized geometries were in good agreement with the crystallographic ones. These results emphasize the capability of the use of the Sparkle Model for the prediction of geometries of compounds containing lanthanide trications within the PM7 semiempirical model, as well as the usefulness of such semiempirical calculations for materials modeling. Sparkle/PM7 is available in the software package MOPAC2012, at no cost for academics and can be obtained from http://openmopac.net.

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“…16 Besides the geometry, this allows the calculation of many other properties of the complexes, such as vibrational spectra, thermodynamic quantities, isotopic substitution effects and force constants, ionization potential, electron densities, dipole moments, etc. 17 The Sparkle/AM1 [18][19][20][21][22][23][24] was mainly designed to predict the ground state geometries of lanthanide complexes at a level of accuracy useful for complex design. 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.…”

Section: Introductionmentioning

confidence: 99%

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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Sparkle/AM1 Structure Modeling of Lanthanum (III) and Lutetium (III) Complexes

Cited by 30 publications

References 22 publications

Structure Modeling of Trivalent Lanthanum and Lutetium Complexes: Sparkle/PM3

Structure Modeling of Trivalent Lanthanum and Lutetium Complexes: Sparkle/PM3

Sparkle/PM7 Lanthanide Parameters for the Modeling of Complexes and Materials

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

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