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Wei BY, Cao CZ, Cao CT. Influences of polarizability effect of alkyl group and homoring competition effect of substituents on the NMR spectra of salen-type Schiff base. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2021; 59:701-712. [PMID: 33403765 DOI: 10.1002/mrc.5131] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Revised: 12/31/2020] [Accepted: 01/03/2021] [Indexed: 06/12/2023]
Abstract
Salen-type Schiff bases are a kind of important compounds and are widely used. In order to explore the effect of alkyl groups and substituents attached to aromatic ring on the chemical shifts, 63 title compounds were synthesized. Their 1 H NMR and 13 C NMR spectra were obtained; and the effects of the alkyl chain length and substituents on the chemical shifts (δH (CHN), δC (CHN), δH (OH), and δC (COH)) were studied. The results show that (1) the alkyl polarizability effect index (PEI) has an important influence on the chemical shifts of the above four atoms, with the increase of PEI, the values of δH (CHN) and δc(CHN) decrease, and the values of δH (OH) and δC (COH) increase. (2) The influence of substituent X attached to aromatic ring on the chemical shift is related to its position by taking OH or CHN as reference. As for the effect of substituent on the chemical shifts, the effect of Hammett constant σ(X)OH and excited-state substituent parameter σ CC ex X OH with OH as reference are different from that ofσ(X)CHN and σ CC ex X CH N with CHN as reference, and there is a "homoring competition effect" of the substituent. (3) The effect of the cross-interaction between X and OH on the chemical shift is also significantly different due to the different position of X. Quantitative correlation equations against chemical shifts were built for the four atoms, and the stability and prediction ability of the obtained equations were confirmed by leave-one-out cross validation.
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Affiliation(s)
- Bai-Ying Wei
- School of Resource Environment and Safety Engineering, School of Chemistry and Chemical Engineering, Key Laboratory of Theoretical Organic Chemistry and Function Molecule, Ministry of Education, Hunan University of Science and Technology, Xiangtan, China
| | - Chen-Zhong Cao
- School of Resource Environment and Safety Engineering, School of Chemistry and Chemical Engineering, Key Laboratory of Theoretical Organic Chemistry and Function Molecule, Ministry of Education, Hunan University of Science and Technology, Xiangtan, China
| | - Chao-Tun Cao
- School of Resource Environment and Safety Engineering, School of Chemistry and Chemical Engineering, Key Laboratory of Theoretical Organic Chemistry and Function Molecule, Ministry of Education, Hunan University of Science and Technology, Xiangtan, China
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Dobrowolski JC, Dudek WM, Karpińska G, Baraniak A. Substituent Effect in the Cation Radicals of Monosubstituted Benzenes. Int J Mol Sci 2021; 22:6936. [PMID: 34203254 PMCID: PMC8269098 DOI: 10.3390/ijms22136936] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 06/19/2021] [Accepted: 06/22/2021] [Indexed: 01/30/2023] Open
Abstract
In 30 monosubstituted benzene cation radicals, studied at the ωB97XD/aug-cc-pVTZ level, the phenyl rings usually adopt a compressed form, but a differently compressed form-equivalent to an elongated one-may coexist. The computational and literature ionization potentials are well correlated. The geometrical and magnetic aromaticity, estimated using HOMA and NICS indices, show the systems to be structurally aromatic but magnetically antiaromatic or only weakly aromatic. The partial charge is split between the substituent and ring and varies the most at C(ipso). In the ring, the spin is 70%, concentrated equally at the C(ipso) and C(p) atoms. The sEDA(D) and pEDA(D) descriptors of the substituent effect in cation radicals, respectively, were determined. In cation radicals, the substituent effect on the σ-electron system is like that in the ground state. The effect on the π-electron systems is long-range, and its propagation in the radical quinone-like ring is unlike that in the neutral molecules. The pEDA(D) descriptor correlates well with the partial spin at C(ipso) and C(p) and weakly with the HOMA(D) index. The correlation of the spin at the ring π-electron system and the pEDA(D) descriptor shows that the electron charge supplied to the ring π-electron system and the spin flow oppositely.
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Affiliation(s)
- Jan Cz. Dobrowolski
- National Medicines Institute, 00-725 Warsaw, Poland; (G.K.); (A.B.)
- Institute of Nuclear Chemistry and Technology, 03-195 Warsaw, Poland;
| | - Wojciech M. Dudek
- Institute of Nuclear Chemistry and Technology, 03-195 Warsaw, Poland;
| | | | - Anna Baraniak
- National Medicines Institute, 00-725 Warsaw, Poland; (G.K.); (A.B.)
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Cao C, Yan L, Cao C. Determination and application of the excited‐state substituent constants of pyridyl and substituted phenyl groups. J PHYS ORG CHEM 2021. [DOI: 10.1002/poc.4246] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Chao‐Tun Cao
- Key Laboratory of Theoretical Organic Chemistry and Function Molecule, Ministry of Education, Key Laboratory of QSAR/QSPR of Hunan Provincial University, School of Chemistry and Chemical Engineering Hunan University of Science and Technology Xiangtan China
| | - Lu Yan
- Key Laboratory of Theoretical Organic Chemistry and Function Molecule, Ministry of Education, Key Laboratory of QSAR/QSPR of Hunan Provincial University, School of Chemistry and Chemical Engineering Hunan University of Science and Technology Xiangtan China
| | - Chenzhong Cao
- Key Laboratory of Theoretical Organic Chemistry and Function Molecule, Ministry of Education, Key Laboratory of QSAR/QSPR of Hunan Provincial University, School of Chemistry and Chemical Engineering Hunan University of Science and Technology Xiangtan China
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Dobrowolski JC, Karpińska G. Substituent Effect in the First Excited Triplet State of Monosubstituted Benzenes. ACS OMEGA 2020; 5:9477-9490. [PMID: 32363300 PMCID: PMC7191863 DOI: 10.1021/acsomega.0c00712] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 03/16/2020] [Indexed: 05/08/2023]
Abstract
The structure of 30 monosubstituted benzenes in the first excited triplet T1 state was optimized with both unrestricted (U) and restricted open shell (RO) approximations combined with the ωB97XD/aug-cc-pVTZ basis method. The substituents exhibited diverse σ- and π-electron-donating and/or -withdrawing groups. Two different positions of the substituents are observed in the studied compounds in the T1 state: one distorted from the plane and the other coplanar with a quinoidal ring. The majority of the substituents are π-electron donating in the first group while π-electron withdrawing in the second one. Basically, U- and RO-ωB97XD approximations yield concordant results except for the B-substituents and a few of the planar groups. In the T1 state, the studied molecules are not aromatic, yet aromaticity estimated using the HOMA (harmonic oscillator model of aromaticity) index increases from ca. -0.2 to ca. 0.4 with substituent distortion, while in the S1 state, they are only slightly less aromatic than in the ground state (HOMA ≈0.8 vs ≈1.0, respectively). Unexpectedly, the sEDA(T1) and pEDA(T1) substituent effect descriptors do not correlate with analogous parameters for the ground and first excited singlet states. This is because in the T1 state, the geometry of the ring changes dramatically and the sEDA(T1) and pEDA(T1) descriptors do not characterize only the functional group but the entire molecule. Thus, they cannot provide useful scales for the substituents in the T1 states. We found that the spin density in the T1 states is accumulated at the Cipso and Cp atoms, and with the substituent deformation angle, it nonlinearly increases at the former while decreases at the latter. It appeared that the gap between singly unoccupied molecular orbital and singly occupied molecular orbital (SUMO-SOMO) is determined by the change of the SOMO energy because the former is essentially constant. For the nonplanar structures, SOMO correlates with the torsion angle of the substituent and the ground-state pEDA(S0) descriptor of the π-electron-donating substituents ranging from 0.02 to 0.2 e. Finally, shapes of the SOMO-1 instead of SOMO frontier orbitals in the T1 state somehow resemble the highest occupied molecular orbital ones of the S0 and S1 states. For several planar systems, the shape of the U- and RO-density functional theory-calculated SOMO-1 orbitals differs substantially.
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Yuan H, Chen PW, Li MY, Zhang Y, Peng ZW, Liu W, Paton RS, Cao C. Effects of substituents X and Y on the NMR chemical shifts of 2-(4-X phenyl)-5-Y pyrimidines. J Mol Struct 2020. [DOI: 10.1016/j.molstruc.2019.127489] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Cao C, Zhou W, Cao C. Additional effect of para‐hydroxyl on the reduction potentials of theN‐benzylidenebenzenamines. J PHYS ORG CHEM 2019. [DOI: 10.1002/poc.4028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Chao‐Tun Cao
- Key Laboratory of Theoretical Organic Chemistry and Function Molecule, Ministry of Education, Hunan Provincial University Key Laboratory of QSAR/QSPR, School of Chemistry and Chemical EngineeringHunan University of Science and Technology Xiangtan China
| | - Wei Zhou
- Key Laboratory of Theoretical Organic Chemistry and Function Molecule, Ministry of Education, Hunan Provincial University Key Laboratory of QSAR/QSPR, School of Chemistry and Chemical EngineeringHunan University of Science and Technology Xiangtan China
| | - Chenzhong Cao
- Key Laboratory of Theoretical Organic Chemistry and Function Molecule, Ministry of Education, Hunan Provincial University Key Laboratory of QSAR/QSPR, School of Chemistry and Chemical EngineeringHunan University of Science and Technology Xiangtan China
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Yuan H, Li MY, Chen CN, Zhang Y, Liu WQ. Substituent effects on the UV absorption energy of 2,5-disubstituted pyrimidines. J PHYS ORG CHEM 2018. [DOI: 10.1002/poc.3860] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Hua Yuan
- Key Laboratory of Theoretical Organic Chemistry and Function Molecule, Ministry of Education, Hunan Provincial Key Laboratory of Controllable Preparation and Functional Application of Fine Polymers, National Demonstration Center for Experimental Chemical Engineering and Materials, School of Chemistry and Chemical Engineering; Hunan University of Science and Technology; Xiangtan 411201 Hunan Province PR China
| | - Meng-Yang Li
- Key Laboratory of Theoretical Organic Chemistry and Function Molecule, Ministry of Education, Hunan Provincial Key Laboratory of Controllable Preparation and Functional Application of Fine Polymers, National Demonstration Center for Experimental Chemical Engineering and Materials, School of Chemistry and Chemical Engineering; Hunan University of Science and Technology; Xiangtan 411201 Hunan Province PR China
| | - Chun-Ni Chen
- Key Laboratory of Theoretical Organic Chemistry and Function Molecule, Ministry of Education, Hunan Provincial Key Laboratory of Controllable Preparation and Functional Application of Fine Polymers, National Demonstration Center for Experimental Chemical Engineering and Materials, School of Chemistry and Chemical Engineering; Hunan University of Science and Technology; Xiangtan 411201 Hunan Province PR China
| | - Yan Zhang
- Key Laboratory of Theoretical Organic Chemistry and Function Molecule, Ministry of Education, Hunan Provincial Key Laboratory of Controllable Preparation and Functional Application of Fine Polymers, National Demonstration Center for Experimental Chemical Engineering and Materials, School of Chemistry and Chemical Engineering; Hunan University of Science and Technology; Xiangtan 411201 Hunan Province PR China
| | - Wan-Qiang Liu
- Key Laboratory of Theoretical Organic Chemistry and Function Molecule, Ministry of Education, Hunan Provincial Key Laboratory of Controllable Preparation and Functional Application of Fine Polymers, National Demonstration Center for Experimental Chemical Engineering and Materials, School of Chemistry and Chemical Engineering; Hunan University of Science and Technology; Xiangtan 411201 Hunan Province PR China
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Dobrowolski JC, Lipiński PFJ, Karpińska G. Substituent Effect in the First Excited Singlet State of Monosubstituted Benzenes. J Phys Chem A 2018; 122:4609-4621. [PMID: 29698609 DOI: 10.1021/acs.jpca.8b02209] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
sEDA, pEDA, and cSAR descriptors of the substituent effect were determined for >30 monosubstituted benzenes in the first excited singlet S1 state at the LC-ωB97XD/aug-cc-pVTZ level. It was found that in the S1 state, the σ- and π-valence electrons are a bit less and a bit more affected, respectively, than in the S0 state, but basically, the effect in both states remains the same. In the S0 and S1 states, the d(C-X) distances to the substituent's first atom and the ring perimeter correlate with the sEDA and pEDA in the appropriate states, respectively. The energies and the gap of the frontier orbitals in the two states are linearly correlated and for the HOMO(S1), LUMO(S1), and HOMO(S1)-LUMO(S1) gap correlate also with the pEDA(S1) and cSAR(S1) descriptors. In all studied correlations, three similar groups of substituents can be distinguished, for which correlations (i) are very good, (ii) deviate slightly, and (iii) deviate significantly. Comparison of the shape of the HOMO(S0) and HOMO(S1) orbitals shows that for case (i) HOMO orbitals exhibit almost perfect antisymmetry against the benzene plane, for case (ii) the antisymmetry of HOMO in one of the states is either perturbed or changed, and for case (iii) one HOMO state has σ-character.
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Affiliation(s)
- Jan Cz Dobrowolski
- Department for Medicines Biotechnology and Bioinformatics , National Medicines Institute , 30/34 Chełmska Street , 00-725 Warsaw , Poland
| | - Piotr F J Lipiński
- Department of Neuropeptides , Mossakowski Medical Research Centre PAS , 5 Pawińskiego Street , 02-106 Warsaw , Poland
| | - Grażyna Karpińska
- Department for Medicines Biotechnology and Bioinformatics , National Medicines Institute , 30/34 Chełmska Street , 00-725 Warsaw , Poland
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Is there substituent cross-interaction effect in all the conjugated systems containing C N polar bond? The substituent effects on the NMR chemical shifts of 2,5-disubstituted pyrimidines. J Mol Struct 2018. [DOI: 10.1016/j.molstruc.2017.10.111] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Qu J, Cao CT, Cao C. Determining the excited-state substituent constants of furyl and thienyl groups. J PHYS ORG CHEM 2018. [DOI: 10.1002/poc.3799] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Junyan Qu
- Key Laboratory of Theoretical Organic Chemistry and Function Molecule, Ministry of Education, Key Laboratory of QSAR/QSPR of Hunan Provincial University, School of Chemistry and Chemical Engineering; Hunan University of Science and Technology; Xiangtan China
| | - Chao-Tun Cao
- Key Laboratory of Theoretical Organic Chemistry and Function Molecule, Ministry of Education, Key Laboratory of QSAR/QSPR of Hunan Provincial University, School of Chemistry and Chemical Engineering; Hunan University of Science and Technology; Xiangtan China
| | - Chenzhong Cao
- Key Laboratory of Theoretical Organic Chemistry and Function Molecule, Ministry of Education, Key Laboratory of QSAR/QSPR of Hunan Provincial University, School of Chemistry and Chemical Engineering; Hunan University of Science and Technology; Xiangtan China
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