Bond polarity index: application to group electronegativity

Reed, Lynne H.; Allen, Leland C.

doi:10.1021/j100180a032

Cited by 56 publications

(46 citation statements)

References 1 publication

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“…The Clc~C3 bond in 24CLPD is longer than in 24MOPD by more than 2o-and the C3--C2 bond in 24CLPD is shorter than in 24MOPD by more than 4o-. This is consistent with the recently proposed bond polarity indexes, related to the group electronegativity of C1-and MeOgroups [MeO approximated by OH since it is not included in the list (Reed & Allen, 1992)]. Because of its higher electronegativity, the C1 atom is expected to disturb the 7r-conjugated system in the Phc--C--C fragment to a greater extent than the methoxy group.…”

Section: Commentsupporting

confidence: 88%

Structures of 1,1-diphenyl-2-aza-1,3-butadienes. IV. 3-Cyano-4-(2,4-dichlorophenyl)-1,1-diphenyl-2-aza-1,3-butadiene (24CLPD) and 3-cyano-4-(2,4-dimethoxyphenyl)-1,1-diphenyl-2-aza-1,3-butadiene (24MOPD)

Macicek¹,

Angelova²,

Dryanska³

1993

Acta Crystallogr C

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Section: Commentsupporting

confidence: 88%

Structures of 1,1-diphenyl-2-aza-1,3-butadienes. IV. 3-Cyano-4-(2,4-dichlorophenyl)-1,1-diphenyl-2-aza-1,3-butadiene (24CLPD) and 3-cyano-4-(2,4-dimethoxyphenyl)-1,1-diphenyl-2-aza-1,3-butadiene (24MOPD)

Macicek¹,

Angelova²,

Dryanska³

1993

Acta Crystallogr C

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“…The greater binding affinity of Pb(II) to NACA than to NAC, as observed by XPS and HPLC, is also incongruent with known electronegativities of the –OH and –NH 2 functional groups, which in NAC and NACA differ in structure. Since –OH is the more electronegative than –NH 2 based on the bond polarity index [34], a greater affinity of Pb(II) to NAC than Pb-NACA binding would have been predicted; however, both HPLC and XPS results showed the opposite trend. This finding indicates that it is the interplay of a variety of interatomic forces (not electrostatic ones only) between Pb(II) interacting with multiple atoms within the ligand that governs the binding strength of the antioxidant chelator molecule.…”

Section: Resultsmentioning

confidence: 99%

Characterizing N-acetylcysteine (NAC) and N-acetylcysteine amide (NACA) binding for lead poisoning treatment

Chen

Erçal

Huynh

et al. 2012

Journal of Colloid and Interface Science

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Using antioxidants is an important means of treating lead poisoning. Prior in vivo studies showed marked differences between various chelator antioxidants in their ability to decrease both blood Pb(II) levels and oxidative stress resulting from lead poisoning. The comparative abilities of NAC and NACA to Pb(II) were studied in vitro, for the first time, to examine the role of the –OH/–NH2 functional group in antioxidant binding behavior. To assay the antioxidant-divalent metal interaction, the antioxidants were probed as solid surfaces, adsorbing Pb(II) onto them. Surface characterization was carried out using X-ray photoelectron spectroscopy (XPS) analysis to quantify Pb(II) in the resulting adducts. XPS of the Pb 4f orbitals showed that more Pb(II) was chemically bound to NACA than NAC. In addition, the antioxidant surfaces were probed via point-of-zero charge (PZC) measurements of NAC and NACA were obtained to gain further insight into the Pb-NAC and Pb-NACA binding, showing that Coulombic interactions played a partial role facilitating complex formation. The data correlated well with solution analysis of metal-ligand complexation. UV-vis spectroscopy was used to probe complexation behavior. NACA was found to have the higher binding affinity as shown by free Pb(II) available in solution after complexation from HPLC data. Electrospray ionization mass spectrometry (ESI-MS) was applied to delineate the structures of Pb-antioxidant complexes. Experimental results were further supported by density functional theory (DFT) calculations of supermolecular interaction energies (Einter) showing a greater interaction of Pb(II) with NACA than NAC.

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“…It should be noted that the existence of a linear dependence of [9] in organic solvents may be expected on the basis of polarographic data. 36 Previous to our investigations the experimental support was obtained for methylmercury derivatives in water.…”

Section: The Relative Electronegativity Of L N M Groupsmentioning

confidence: 99%

“…The polarity of s-bonds has a substantial effect on their energy. [6][7][8][9][10][11][12][13][14][15] Novel atomic electronegativity (AEN) scales have been proposed [16][17][18] and quantumchemical calculations of GEN have been carried out for a number of the simplest organic and organoelement groups L n E containing elements of II and III Periods (E = C, N, O, P, S). 5 It is obvious that the above properties should depend on such fundamental characteristics of L n M groups as electronegativity and hardness.…”

Section: Introductionmentioning

confidence: 99%

Electronegativity and chemical hardness of organoelement groups

Peregudov

Kravtsov

2001

Appl. Organometal. Chem.

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Q = O, S), containing a great variety of different organometallic groups containing transition or heavy main-group metals. The data on chemical hardness of L n M groups were obtained from NMR study of distribution of different L n M groups between hard and soft anions. The following basic results have been obtained. (1) The relative electronegativity and chemical hardness of L n M groups can change in parallel or not with the electronegativity and hardness of the central metal atom. (2) The substituents in Ar can substantially modify electronegativity and hardness of Ar n M groups; the influence of Ar groups has an inductive nature; the increase in electrondonating ability of aryl ligands enhances the hardness of Ar n M cations. (3) The relative electronegativity and hardness of L n M groups in L n MX are invariant and do not depend on X.

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Bond polarity index: application to group electronegativity

Cited by 56 publications

References 1 publication

Structures of 1,1-diphenyl-2-aza-1,3-butadienes. IV. 3-Cyano-4-(2,4-dichlorophenyl)-1,1-diphenyl-2-aza-1,3-butadiene (24CLPD) and 3-cyano-4-(2,4-dimethoxyphenyl)-1,1-diphenyl-2-aza-1,3-butadiene (24MOPD)

Structures of 1,1-diphenyl-2-aza-1,3-butadienes. IV. 3-Cyano-4-(2,4-dichlorophenyl)-1,1-diphenyl-2-aza-1,3-butadiene (24CLPD) and 3-cyano-4-(2,4-dimethoxyphenyl)-1,1-diphenyl-2-aza-1,3-butadiene (24MOPD)

Characterizing N-acetylcysteine (NAC) and N-acetylcysteine amide (NACA) binding for lead poisoning treatment

Electronegativity and chemical hardness of organoelement groups

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