Pub Date : 2020-06-19DOI: 10.5772/INTECHOPEN.92768
G. Tian, Weizhong Zhou
Three sets of ionic liquids such as 1-alkyl-3-methylimidazole chloride [Cnmim]Cl, 1-alkyl-3-methylimidazolium acetate [Cnmim]Ac and 1-octyl-3-methylimidazole salt [Omim]Y (n = 2, 4, 6, 8, and Y = Cl, BF4, HSO4, Ac and TFO) were used as corrosion inhibitor medium for corrosion protection of carbon steel. Electronic structures and reactivity of these ionic liquids, surface energy and electronic structures of the iron surface were systematically analyzed by density functional theory. By increasing the alkyl chain length of the [Cnmim]Cl and [Cnmim]Ac systems, the lowest unoccupied molecular orbital energy (ELUMO), the highest occupied molecular orbital energy (EHOMO), the softness (S) and polarizability (α) increased gradually, whereas electronegativity (χ), energy gap (ΔE), hardness (η), dipole moment (μ)and electrophilic index (ω) gradually decreased. For the [Omim]Y system, the structure parameters of ionic liquids are quite different, and only the polarizability (α) decreases gradually by increasing the length of the alkyl chain. The results show that inhibition is mainly [Cnmim]+ cations of the [Cnmim]Cl system, and the order of inhibition efficiency follows as [C2mim]Cl < [C4mim]Cl < [C6mim]Cl < [C8mim]Cl. Both [Cnmim]+ cations and the Ac− anion have inhibition effect for the [Xmim]Ac system, and the order of inhibition efficiency is [C8mim]Ac > [C6mim]Ac > [C4mim]Ac > [C2mim]Ac. For the [Omim]Y system, [Xmim]+ cations and anions (BF4−, HSO4−, Ac−, TfO−) have inhibition effect, and the order of inhibition efficiency is [Omim]TfO > [Omim]Ac > [Omim]HSO4 > [Omim]BF4 > [Omim]Cl.
{"title":"Theoretical Study of the Structure and Property of Ionic Liquids as Corrosion Inhibitor","authors":"G. Tian, Weizhong Zhou","doi":"10.5772/INTECHOPEN.92768","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.92768","url":null,"abstract":"Three sets of ionic liquids such as 1-alkyl-3-methylimidazole chloride [Cnmim]Cl, 1-alkyl-3-methylimidazolium acetate [Cnmim]Ac and 1-octyl-3-methylimidazole salt [Omim]Y (n = 2, 4, 6, 8, and Y = Cl, BF4, HSO4, Ac and TFO) were used as corrosion inhibitor medium for corrosion protection of carbon steel. Electronic structures and reactivity of these ionic liquids, surface energy and electronic structures of the iron surface were systematically analyzed by density functional theory. By increasing the alkyl chain length of the [Cnmim]Cl and [Cnmim]Ac systems, the lowest unoccupied molecular orbital energy (ELUMO), the highest occupied molecular orbital energy (EHOMO), the softness (S) and polarizability (α) increased gradually, whereas electronegativity (χ), energy gap (ΔE), hardness (η), dipole moment (μ)and electrophilic index (ω) gradually decreased. For the [Omim]Y system, the structure parameters of ionic liquids are quite different, and only the polarizability (α) decreases gradually by increasing the length of the alkyl chain. The results show that inhibition is mainly [Cnmim]+ cations of the [Cnmim]Cl system, and the order of inhibition efficiency follows as [C2mim]Cl < [C4mim]Cl < [C6mim]Cl < [C8mim]Cl. Both [Cnmim]+ cations and the Ac− anion have inhibition effect for the [Xmim]Ac system, and the order of inhibition efficiency is [C8mim]Ac > [C6mim]Ac > [C4mim]Ac > [C2mim]Ac. For the [Omim]Y system, [Xmim]+ cations and anions (BF4−, HSO4−, Ac−, TfO−) have inhibition effect, and the order of inhibition efficiency is [Omim]TfO > [Omim]Ac > [Omim]HSO4 > [Omim]BF4 > [Omim]Cl.","PeriodicalId":403695,"journal":{"name":"Density Functional Theory Calculations","volume":"74 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120873645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-03-11DOI: 10.5772/INTECHOPEN.90531
Rakesh Kumar, S. Obrai
The computational study of some s-block metal nitrophenolate complexes, [Ca(THEEN)(PIC)]+ (1), [Ca(THPEN)(H2O)2]2+ (2), Ba(THPEN)(PIC)2 (3) [Na(THPEN)]22+ (4), [Sr(THPEN)(H2O)2]22+ (5) and [Ba(THPEN)(H2O)2]22+ (6) (where THEEN (N,N,N′,N′-Tetrakis(2-hydroxyethyl)ethylenediamine) and THPEN (N,N,N′,N′-Tetrakis(2-hydroxypropyl)ethylenediamine) are tetrapodal ligands and PIC− is 2,4,6-trinitrophenolate anion), is presented here using density functional theory (DFT) in its hybrid form B3LYP. The geometries of the title complexes are described by the quantum-chemical approach using input coordinates obtained from the previously synthesized and X-ray characterized diffraction data of [Ca(THEEN)(PIC)](PIC), [Ca(THPEN)(H2O)2](PIC)2, Ba(THPEN)(PIC)2, [Na(THPEN)]2(PIC)2, [Sr(THPEN)(H2O)2]2(DNP)4 and [Ba(THPEN)(H2O)2]2(DNP)4 (where DNP is 3,5-dinitrophenolate). Only the primary coordination sphere of complexes (1–6) is optimized in the gaseous phase. Calculations of the energy gaps of frontier orbitals (HOMO-LUMO), 13C-NMR shifts and vibrational bands are carried out using B3LYP/6-31 g + (d,p)/LANL2DZ level of theory. The calculated geometric and spectral parameters reproduced the experimental data with a well agreement.
{"title":"Quantum Computational Chemistry: Modeling and Calculation of S-Block Metal Ion Complexes","authors":"Rakesh Kumar, S. Obrai","doi":"10.5772/INTECHOPEN.90531","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.90531","url":null,"abstract":"The computational study of some s-block metal nitrophenolate complexes, [Ca(THEEN)(PIC)]+ (1), [Ca(THPEN)(H2O)2]2+ (2), Ba(THPEN)(PIC)2 (3) [Na(THPEN)]22+ (4), [Sr(THPEN)(H2O)2]22+ (5) and [Ba(THPEN)(H2O)2]22+ (6) (where THEEN (N,N,N′,N′-Tetrakis(2-hydroxyethyl)ethylenediamine) and THPEN (N,N,N′,N′-Tetrakis(2-hydroxypropyl)ethylenediamine) are tetrapodal ligands and PIC− is 2,4,6-trinitrophenolate anion), is presented here using density functional theory (DFT) in its hybrid form B3LYP. The geometries of the title complexes are described by the quantum-chemical approach using input coordinates obtained from the previously synthesized and X-ray characterized diffraction data of [Ca(THEEN)(PIC)](PIC), [Ca(THPEN)(H2O)2](PIC)2, Ba(THPEN)(PIC)2, [Na(THPEN)]2(PIC)2, [Sr(THPEN)(H2O)2]2(DNP)4 and [Ba(THPEN)(H2O)2]2(DNP)4 (where DNP is 3,5-dinitrophenolate). Only the primary coordination sphere of complexes (1–6) is optimized in the gaseous phase. Calculations of the energy gaps of frontier orbitals (HOMO-LUMO), 13C-NMR shifts and vibrational bands are carried out using B3LYP/6-31 g + (d,p)/LANL2DZ level of theory. The calculated geometric and spectral parameters reproduced the experimental data with a well agreement.","PeriodicalId":403695,"journal":{"name":"Density Functional Theory Calculations","volume":"55 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120844215","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-08-14DOI: 10.5772/INTECHOPEN.88657
N. Flores-Holguín, J. Frau, D. Glossman-Mitnik
A well-behaved model chemistry previously validated for the study of the chemical reactivity of peptides was considered for the calculation of the molecular properties and structures of the clavanin family of antimicrobial marine peptides. A methodology based on conceptual density functional theory (CDFT) was chosen for the determination of the reactivity descriptors. The molecular active sites were associated with the active regions of the molecules related to the nucleophilic and electrophilic Fukui functions. Finally, the drug-likenesses and the bioactivity scores for the clavanin peptides were predicted through a homology methodology relating them with the calculated reactivity descriptors, while other properties like the pKas were determined following a methodology developed by our group.
{"title":"Conceptual DFT as a Helpful Chemoinformatics Tool for the Study of the Clavanin Family of Antimicrobial Marine Peptides","authors":"N. Flores-Holguín, J. Frau, D. Glossman-Mitnik","doi":"10.5772/INTECHOPEN.88657","DOIUrl":"https://doi.org/10.5772/INTECHOPEN.88657","url":null,"abstract":"A well-behaved model chemistry previously validated for the study of the chemical reactivity of peptides was considered for the calculation of the molecular properties and structures of the clavanin family of antimicrobial marine peptides. A methodology based on conceptual density functional theory (CDFT) was chosen for the determination of the reactivity descriptors. The molecular active sites were associated with the active regions of the molecules related to the nucleophilic and electrophilic Fukui functions. Finally, the drug-likenesses and the bioactivity scores for the clavanin peptides were predicted through a homology methodology relating them with the calculated reactivity descriptors, while other properties like the pKas were determined following a methodology developed by our group.","PeriodicalId":403695,"journal":{"name":"Density Functional Theory Calculations","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114948849","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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