Solvent Effects on the Electronic Spectra of Transition Metal Complexes

Hush, Noel S.; Reimers, Jeffrey R.

doi:10.1021/cr980409v

Cited by 99 publications

(77 citation statements)

References 73 publications

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“…[1][2][3] These shifts are caused by a different stabilization of ground and excited states by the solvent within the Franck-Condon region, i.e., without a reorientation of the solvent molecules upon absorption or emission. In recent time, several attempts have been made to model the solvatochromic shifts of simple compounds such as acetone, 4,5 triazines or tetrazines, [6][7][8] solvatochromic organic dyes, [9][10][11] or transition metal compounds [12][13][14][15] with different explicit or implicit models for the solvent.…”

Section: Introductionmentioning

confidence: 99%

The merits of the frozen-density embedding scheme to model solvatochromic shifts

Neugebauer

Louwerse

Baerends

et al. 2005

The Journal of Chemical Physics

235

373

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We investigate the usefulness of a frozen-density embedding scheme within density-functional theory ͓J. Phys. Chem. 97, 8050 ͑1993͔͒ for the calculation of solvatochromic shifts. The frozen-density calculations, particularly of excitation energies have two clear advantages over the standard supermolecule calculations: ͑i͒ calculations for much larger systems are feasible, since the time-consuming time-dependent density functional theory ͑TDDFT͒ part is carried out in a limited molecular orbital space, while the effect of the surroundings is still included at a quantum mechanical level. This allows a large number of solvent molecules to be included and thus affords both specific and nonspecific solvent effects to be modeled. ͑ii͒ Only excitations of the system of interest, i.e., the selected embedded system, are calculated. This allows an easy analysis and interpretation of the results. In TDDFT calculations, it avoids unphysical results introduced by spurious mixings with the artificially too low charge-transfer excitations which are an artifact of the adiabatic local-density approximation or generalized gradient approximation exchange-correlation kernels currently used. The performance of the frozen-density embedding method is tested for the well-studied solvatochromic properties of the n → * excitation of acetone. Further enhancement of the efficiency is studied by constructing approximate solvent densities, e.g., from a superposition of densities of individual solvent molecules. This is demonstrated for systems with up to 802 atoms. To obtain a realistic modeling of the absorption spectra of solvated molecules, including the effect of the solvent motions, we combine the embedding scheme with classical molecular dynamics ͑MD͒ and Car-Parrinello MD simulations to obtain snapshots of the solute and its solvent environment, for which then excitation energies are calculated. The frozen-density embedding yields estimated solvent shifts in the range of 0.20-0.26 eV, in good agreement with experimental values of between 0.19 and 0.21 eV.

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Section: Introductionmentioning

confidence: 99%

The merits of the frozen-density embedding scheme to model solvatochromic shifts

Neugebauer

Louwerse

Baerends

et al. 2005

The Journal of Chemical Physics

235

373

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“…16,17 However, the metabolic action and mechanism and fate of thallium toxicity are still not well understood, though there is some experimental evidence that suggests sulfur-containing compounds have been the main detoxifying drug in the case of poisoning. 17,18 Since thallium(I) shows marked similarities to that of potassium cation, 19 its interaction with nucleotides, the monomeric units of DNA and RNA, would be of major biochemical interest.…”

Section: Introductionmentioning

confidence: 99%

Complexation of Thallium(I) with Adenosine 5′-Monophosphate in Aqueous Methanol Solutions

2005

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The development of various kinds of approaches to hydrophobic hydration is necessary for a better understanding of its key role in controlling biochemical processes in water. 1,2 In the last few years, several experimental and theoretical works dealing with the effect of solvent on many reactions have been published. [3][4][5] Most of these papers are concerned with the effect of solvent on reaction rates. There is surprisingly little work, involving the effect of solvent on the thermodynamics and complexation of some biologically important ligands. [6][7][8] Various empirical solvent polarity parameters have been used to describe the influence of solvents on physicochemical solute properties. 9One particularly useful set consists of complementary Lewis acid-base solvent parameters, now known for most common organic solvents.10,11 It was found for example, by analysis of the variation of Kamlet-Taft's, β and α values, 12 for mixtures of methanol and other organic solvents, that one important factor influencing the basicity or acidity of solvent mixtures is due to an order/disorder process, particularly in binary mixtures of protic solvents with non-hydrogen bond donor (non-HBD) solvents. 12,13 Nucleotides play a key role in almost all kinds of metabolic processes. Much effort was devoted to the complexes of AMP, adenosine 5′-monophosphate, with metal ions. The properties and structures of binary complexes of most metal ion-AMP systems in aqueous solution are now relatively well described.14,15 Depending on the kind of metal ion involved, coordination occurs not only to the phosphate chain but also to N-1, leading thus to macrochelates.Thallium has been recognized as a toxic element for many years. It produces a variety of adverse effects in human beings. This element acts on the central nervous system and induces an inflammatory response. 16,17 However, the metabolic action and mechanism and fate of thallium toxicity are still not well understood, though there is some experimental evidence that suggests sulfur-containing compounds have been the main detoxifying drug in the case of poisoning. 17,18 Since thallium(I) shows marked similarities to that of potassium cation, 19 its interaction with nucleotides, the monomeric units of DNA and RNA, would be of major biochemical interest.This work deals with the study of thallium(I) complexes by AMP and the determination their stability constants in different solutions of methanol + water to show how the solvent and their mixtures with various dielectric constants affect the complexation.Recently, more attention has been paid to binary solvent mixtures in this field. 20-22 Solute-solvent interactions are much more complex in mixed solvent systems than in pure solvents, due to the possibility of preferential solvation by any of the solvents present in the mixtures. Moreover, the solvent-solvent interactions produced in solvent mixtures can affect the solutesolvent interactions and therefore they can also affect preferential solvations. 23At present, there are two more imp...

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“…[3][4][5][6][7][8][9][10][11] one of the most interesting is that proposed by Kamlet and Taft. 12 Recently, solvent effects on transition metal complexes were reviewed 13 and more attention has been paid to binary solvent mixtures in this field.…”

Section: Introductionmentioning

confidence: 99%

Solvent Effects on Complexation of Molybdenum(VI) with Nitrilotriacetic Acid in Different Aqueous Solutions of Propanol

Mohammadi

2007

Chin. J. Chem.

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By using spectrophotometric and potentiometric techniques the formation constants of the species formed in the systems H ＋＋Mo(VI)＋nitrilotriacetic acid and H ＋＋nitrilotriacetic acid have been determined in aqueous solutions of propanol at 25 ℃ and constant ionic strength 0.1 mol•dm -3 sodium perchlorate. The composition of the complex was determined by the continuous variation method. It was shown that molybdenum(VI) forms a mononuclear 1∶1 complex with nitrilotriacetic acid of the type MoO 3 L -3 at -lg[H ＋ ]＝5.8. The formation constants in various media were analyzed in terms of Kamlet and Taft's parameters. Linear relationships were observed when lg K S was plotted versus p*. Finally, the results were discussed in terms of the effect of solvent on complexation.

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Solvent Effects on the Electronic Spectra of Transition Metal Complexes

Cited by 99 publications

References 73 publications

The merits of the frozen-density embedding scheme to model solvatochromic shifts

The merits of the frozen-density embedding scheme to model solvatochromic shifts

Complexation of Thallium(I) with Adenosine 5′-Monophosphate in Aqueous Methanol Solutions

Solvent Effects on Complexation of Molybdenum(VI) with Nitrilotriacetic Acid in Different Aqueous Solutions of Propanol

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