Theoretical studies on the first proton macroaffinity of Ni(ii), Cu(ii), Zn(ii) and Cd(ii) complexes of four triazacycloalkanes ([X]ane N3, X = 9–12): good correlations with the formation constants in solution

Salehzadeh, Sadegh; Shooshtari, Amir; Bayat, Mehdi

doi:10.1039/b822260f

Cited by 16 publications

(13 citation statements)

References 11 publications

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“…Also, a LFER correlation between the DFT-calculated gas-phase proton macroaffinities (first protonation step) of metal complexes with the tripodal tetraamine ligands 14 and triazacycloalkanes 15 and corresponding formation constants in solution (log K 1 )…”

Section: But This Does Not Apply To the Formation Constants Of Metal mentioning

confidence: 99%

A Density Functional Theory- and Atoms in Molecules-based Study of NiNTA and NiNTPA Complexes toward Physical Properties Controlling their Stability. A New Method of Computing a Formation Constant

Cukrowski

Govender

2010

Inorg. Chem.

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The log K 1 value of analytical quality was obtained for the NiNTPA complex using the DFTcomputed (at the B3LYP/6-311++G(d,p) level of theory in solvent, CPCM/UAKS) G (aq) values of the lowest energy conformers of the ligands, NTA (nitrilotriacetic acid) and NTPA (nitrilotri-3-propanoic acid), and Ni(II) complexes (NiNTA and NiNTPA). The described mathematical protocol is of general nature. The topological analysis, based on the Quantum Theory of Atoms in Molecules (QTAIM) of Bader, was used to characterize coordination bonds, chelating rings and additional intramolecular interactions in the complexes. The topological data, but not the structural analysis, explained the observed difference in stability of the NiNTA and NiNTPA complexes. It was found that the structural H···H contacts (classically regarded H-clashes, a steric hindrance destabilizing the complex) are in fact the H-H bonds contributing to the overall stability of NiNTPA. Also a CH-O bond was found in NiNTPA. The absence of intramolecular bonds between the atoms that fulfill a distance criterion in NiNTPA is explained by the formation of adjacent intramolecular rings that have larger electron density at the ring critical points when compared with the rings containing these atoms. It is postulated that the strength of a chelating ring (a chelating effect) can be measured by the electron density at the ring critical point. It was found that the strain energy, E s , in the as-in-complex NTPA ligand (E s is significantly lowered by the presence of the intramolecular bonded interactions found by QTAIM) is responsible for the decrease in strength of NiNTPA; the E s ratio (NTPA/NTA) of 1.9 correlates well with the experimental log K 1 ratio (NTA/NTPA) of 1.98.2

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Section: But This Does Not Apply To the Formation Constants Of Metal mentioning

confidence: 99%

A Density Functional Theory- and Atoms in Molecules-based Study of NiNTA and NiNTPA Complexes toward Physical Properties Controlling their Stability. A New Method of Computing a Formation Constant

Cukrowski

Govender

2010

Inorg. Chem.

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“…(1)- (3) for calculation of first proton macroaffinity of complexes studied here from the corresponding proton microaffinities. 18,19 …”

Section: Proton Affinities and Formation Constantsmentioning

confidence: 98%

“…Obviously, as the stability of a particular metal-ligand complex increases (a result of ligandmetal bonding interactions), the proton affinity of the coordinated ligand will be decreased. 18,19 We remember that the product of the protonation of the metal complex of a polydentate ligand is a new complex in which, at least, one of the donor atoms of the ligand is protonated and removed from the metal ion. Thus, the amount of energy of the protonation process, the proton microaffinity of the complex, depends on the energy difference between the complex and its protonated form.…”

Section: Proton Affinities and Formation Constantsmentioning

confidence: 99%

“…Protonation of each individual basic site of the polydentate ligand corresponds to one proton micoaffinity. 18,19 The number of proton microaffinities depends not only upon the number of basic sites but also upon the symmetry of the complex. 38 The complexes investigated here belong to M(AB 3 ) [i.e., M(tren) and M(tpt)], M(AB 2 C) [i.e., M(pee), M(ppe), and M(ppb)], and M(ABCD) [i.e., M(epb)] general types, in which the bridgehead tertiary amine atom is denoted as A, and the primary amine sites are denoted as B/C/D.…”

Section: Proton Affinities and Formation Constantsmentioning

confidence: 99%

“…19 The basicity has been defined as a change in Gibbs free energy, DG, for protonation process, L 1 H 1 … HL 1 . For calculation of macrobasicities, we simply replaced the PA i , microaffinity, with the DG i , microbasicity, in formulas 1-3 as below 19 :…”

Section: Proton Affinities and Formation Constantsmentioning

confidence: 99%

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Theoretical studies on the structure and protonation of Cu(II) complexes of a series of tripodal aliphatic tetraamines: Good correlations with the experimental data

Salehzadeh

Bayat

2010

J Comput Chem

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DFT(B3LYP) studies on first protonation step of a series of Cu(II) complexes of some tripodal tetraamines with general formula N[(CH(2))(n)NH(2)][(CH(2))(m)NH(2)][(CH(2))(p)NH(2)] (n = m = p = 2, tren; n = 3, m = p = 2, pee; n = m = 3, p = 2, ppe; n = m = 3, tpt; n = 2, m = 3, p = 4, epb; and n = m = 3, p = 4; ppb) are reported. First, the gas-phase proton macroaffinity of all latter complexes was calculated with considering following simple reaction: [Cu(L)](2+)(g) + H(+)(g) --> [Cu(HL)](3+)(g). The results showed that there is a good correlation between the calculated proton macroaffinities of all complexes with their stability constants in solution. Then, we tried to determine the possible reliable structures for microspecies involved in protonation process of above complexes. The results showed that, similar to the solid state, the [Cu(L)(H(2)O)](2+) and [Cu(HL)(H(2)O)(2)](3+) are most stable species for latter complexes and their protonated form, respectively, at gas phase. We found that there are acceptable correlations between the formation constants of above complexes with both the -Delta E and -Delta G of following reaction: [Cu(L)(H(2)O)](2+)(g) + H(+)(g) + H(2)O(g) --> [Cu(HL)(H(2)O)(2)](3+)(g). The -Delta E of the latter reaction can be defined as a theoretically solvent-proton macroaffinity of reactant complexes because they have gained one proton and one molecule of the solvent. The unknown formation constant of [Cu(epb)](2+) complex was also predicted from the observed correlations. In addition, the first proton affinity of all complexes was studied in solution using DPCM and CPCM methods. It was shown that there is an acceptable correlation between the solvent-proton affinities of [Cu(L)(H(2)O)](2+) complexes with formation constants of [Cu(HL)(H(2)O)(2)](3+) complexes in solution.

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From 3D to 2D Transition Metal Nitroprussides by Selective Rupture of Axial Bonds

Ávila

Osiry

Plasencia

et al. 2019

Chemistry A European J

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1-methyl-2-pyrrolidone( 1m2p)i sasolvent with proven abilitiesf or 2D-solid exfoliation due to its extremely high surface tension. In principle, such af eature could be used also to induce the selectiveb reaking of certain bonds in solids to obtain new materials. Such ah ypothesis is demonstrated in this study for transition metal nitroprussides, where 2D solids are obtained from 3D frameworks by selective rupture of axial bonds. This contribution discusses the mechanism involved in such molecular manufacture. The crystal structuref or the formed 2D solids was solved and refined from XRD powder patterns recordedu sing synchrotron radiation.M çssbauer,I Ra nd Ramans pectrap rovided fine details on the electronic structure of the resulting new series of layered materials. The experimental information was complemented with calculations for the molecule configuration in its non-activated and activated forms. In the obtained 2D solids,n eighboring layers of about 1nmo ft hickness remain separated by activated1 m2p molecules. The interaction betweenn eighboring layers is of ap hysicaln ature, withoutt he presence of ac hemical bond between them,a sc orresponds to a2Dm aterial.For 1m2p: n(C =O) = 1688 cm À1 and n(NÀC CH3 ) = 1402 cm À1 ;[ a] Ta ken from Raman spectrum.

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Theoretical studies on the first proton macroaffinity of Ni(ii), Cu(ii), Zn(ii) and Cd(ii) complexes of four triazacycloalkanes ([X]ane N3, X = 9–12): good correlations with the formation constants in solution

Cited by 16 publications

References 11 publications

A Density Functional Theory- and Atoms in Molecules-based Study of NiNTA and NiNTPA Complexes toward Physical Properties Controlling their Stability. A New Method of Computing a Formation Constant

A Density Functional Theory- and Atoms in Molecules-based Study of NiNTA and NiNTPA Complexes toward Physical Properties Controlling their Stability. A New Method of Computing a Formation Constant

Theoretical studies on the structure and protonation of Cu(II) complexes of a series of tripodal aliphatic tetraamines: Good correlations with the experimental data

From 3D to 2D Transition Metal Nitroprussides by Selective Rupture of Axial Bonds

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