Topic
Aquation
About: Aquation is a research topic. Over the lifetime, 1443 publications have been published within this topic receiving 17507 citations.
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TL;DR: In this article, the rate of aquation of tris(5-nitro-1,10-phenanthroline)iron(II) is increased when tetra-n-butylammonium bromide is added but decreased when potassium bromides, tetraethylammiumbromide, tetramerethylammoniam bromidal, tetramethylam-monium (TMB), or caesium Bromide are added.
Abstract: The rate of aquation of tris(5-nitro-1,10-phenanthroline)iron(II) is increased when tetra-n-butylammonium bromide is added but decreased when potassium bromide, tetraethylammonium bromide, tetramethylammonium bromide, or caesium bromide are added. These effects are analysed in terms of salt effects on both the initial and transition states. In this analysis, use is made of the dependence of the solubility of the ligand, 5-nitro-1,10-phenanthroline, in water on added salt and of parameters which describe cation–cation interactions in mixed-salt solutions.
9 citations
TL;DR: In this paper, the authors show that acridinium ion sensitizes both ammonia and thiocyanate aquation, the presence of oxygen affecting the latter but not the former mode.
Abstract: Biacetyl and acridinium ion but not Michler's ketone sensitize the aquation of Cr(NH3
5(NCS)2+ in 0.1 N sulfuric acid solution. Phosphorescence quenching occurs in first system, and the kinetics of this and of the sensitized reaction in the presence and absence of oxygen indicate that transfer of excitation energy occurs from the biacetyl first triplet state. The reaction is entirely one of ammonia aquation, indicating that the first quartet excited state of the complex is populated. Acridinium ion sensitizes both ammonia and thiocyanate aquation, the presence of oxygen affecting the latter but not the former mode. The kinetics of the fluorescence quenching by the complex and that of the sensitized ammonia aquation indicate that the latter process is induced by the first singlet excited state of acridinium ion, along with a small component of thiocyanate aquation. The oxygen dependence results indicate that the remainder of the thiocyanate aquation is induced by the first triplet excited state of the donor. It is concluded that, in this system, the singlet excited state of acridinium ion populates the first quartet excited state of the complex ion while the triplet state populates the doublet excited state of the complex. Some of the complexities of excited state processes of Cr(III) complexes are discussed.
9 citations
TL;DR: In this article, a chiral carboxylic acid (Hbnap), bearing imide and imidazole functionalities with some structural relevance to tryptophan and histidine amino acids, was designed.
Abstract: A chiral carboxylic acid, (−)-N-(2-imidazol-5-yl-1-carboxyethyl)-1,8-naphthalimide (Hbnap), bearing imide and imidazole functionalities with some structural relevance to tryptophan and histidine amino acids, was designed. Various solvates and salts of Hbnap were synthesized and structurally characterized, namely, Hbnap·H2O (1), 4Hbnap·MeOH·3H2O (2), Hbnap·DMSO {DMSO = dimethyl sulfoxide} (3), Hbnap·DMF {DMF = N,N′-dimethylformamide} (4), Hbnap·DMA {DMA = N,N′-dimethylacetamide} (5), Hbnap·2quinoline (6), Hbnap·pyridine (7), bnap·Hdbu·2H2O {dbu = 1,8-diazabicyclo[5.4.0]undec-7-ene} (8), [H2bnap]Br·0.5MeOH (9), [H2bnap]I·0.5MeOH (10), [H2bnap]2SO4·DMF·H2O (11), and [H2bnap]NO3 (12). Their packing patterns were analyzed in detail, showing that an interplay of hydrogen bonds, aquation, and π-stacking control the formation of distinct one-, two-, or three-dimensional (1D, 2D, or 3D) supramolecular assemblies. The H-bonded 2D underlying networks of solvates 1–8 were topologically classified revealing three dist...
9 citations
TL;DR: It is found that there exists little difference in free enthalpies of activation, such that these platinum‐based anticancer drugs are likely to behave the same way in aqueous media.
Abstract: Aquation free energy profiles of neutral cisplatin and cationic monofunctional derivatives, including triaminochloroplatinum(II) and cis-diammine(pyridine)chloroplatinum(II), were computed using state of the art thermodynamic integration, for which temperature and solvent were accounted for explicitly using density functional theory-based canonical molecular dynamics (DFT-MD) For all the systems, the "inverse-hydration" where the metal center acts as an acceptor of hydrogen bond has been observed This has motivated to consider the inversely bonded solvent molecule in the definition of the reaction coordinate required to initiate the constrained DFT-MD trajectories We found that there exists little difference in free enthalpies of activation, such that these platinum-based anticancer drugs are likely to behave the same way in aqueous media Detailed analysis of the microsolvation structure of the square-planar complexes, along with the key steps of the aquation mechanism, is discussed
9 citations