自由基离子的分子结构和超精细结构的理论研究
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摘要
本论文主要研究对象是1-戊烯、2-戊烯、1-己烯、2-己烯、3-己烯、环丁烷和二环[2，2，1]庚烷阳离子自由基，以及硫氧阴离子自由基等。主要运用密度泛函理论中的B3LYP方法计算研究了它们的分子结构、电子态、绝热和垂直电子亲和亲和势以及自旋性质(质子的各向同性超精细偶合常数a(H)值)等，通过和以前文献的结论进行比较，我们得到了新的结论。在此我们以具有代表性的离子自由基为例来论述本论文研究的过程。
烃类自由基阳离子作为化学反应和生化反应的中间体和引发剂，多年来一直受到理论和实验工作者的重视，许多化学家对它们的分子结构和自旋性质进行过研究。在以往关于烯烃阳离子的理论研究，针对乙烯、丙烯阳离子的较多。文献中关于四个或多于四个碳原子的烯烃阳离子的研究报道较少。Lunell等[1]和Bach等曾用非限制性HF理论、非限制性Moller-Plesset二阶微扰理论(UMP2)和单双激发组态相互作用(SDCI)等方法对1-C_5H_(10)~+，2-C_5H_(10)~+，1-C_6H_(12)~+，2-C_6H_(12)~+和3-C_6H_(12)~+进行了理论计算。本论文使用密度泛函理论B3LYP方法和6-31G(d，p)，6-31+G(d，p)，6-311G(d，p)及6-311+G(d，p)基组，分别对1-C_5H_(10)~+，2-C_5H_(10)~+，1-C_6H_(12)~+，2-C_6H_(12)~+和3-C_6H_(12)~+的各种构象进行了几何构型优化，并用B3LYP／6-311G(d，p)进行了频率分析计算，确定了最稳定构型。计算预言1-C_5H_(10)~+具有非平面陶型，与以往报道的从头算计算结论相反。在各优化构型上，使用B3LYP和MP2(full)方法进行了超精细结构的计算。计算的2-C_5H_(10)~+和3-C_6H_(12)~+的各向同性超精细偶合常数a(H)值比以往的计算结果更好，同时还找到一个非平面的构型，其能量与平面的构型的能量很接近；1-C_5H_(10)~+、1-C_6H_(12)~+和2-C_6H_(12)~+的各向同性超精细偶合常数目前尚无实验数据报道，本计算预言了它们的各向同性超精细偶合常数值a(H)值和最稳定构型。对于环丁烷自由基阳离子，我们用B3LYP方法和各种标准基组研究了它的势能面，得到的电子垂直和绝热亲和势接近
摘要
实验数据。优化得到了平行四边形，菱形和矩形三种构型，而没有得
到梯形的优化构型。所以我们认为具有平行四边形构型的阳离子是最
稳定构型，而不是以前文献报道的梯形构型。固定平行四边形构型碳
骨架二面角，通过部分优化得到构型而计算的各向同性超精细偶合常
数也与实验值吻合得很好。
硫氧化合物在氧化作用中一直被认为是重要的引发剂和中间
体。实验上己经得到了气态游离的二氧化硫和三氧化硫分子的阴离
子，并测得了502一和503一的分子结构和超精细偶合常数值，以及对
应的分子(50:和50;)的绝热电子亲合势(AEA)的实验数据报
道。本论文使用二次组态相互作用(QCISD)方法和6一3 1 10(d)，
6一311+G(d)，6一3llG(Zd)及6一311+G(Zd)基组研究了502一和503一的分
子结构，超精细偶合常数(hfcc)及其对应的分子的绝热电子亲合势
(AEA)。发现在QCISD/6一3 11十G(2d)水平上计算的两个分子离子的
结构，hfcc值(在335和’70上的)和AEA值与实验值符合得都很好
(除503一中的在335上的hfec值比实验值小23%)。作为比较，我
们使用相同基组作了B3LYP方法计算，得到的超精细偶合常数和
AEA值都却与实验符合得不好。
本论文的创新之处在于:(l)计算预一言1一CSH!0一具有非平面构
型，与以往报道的从头算UHF和MPZ等计算结论(平面构型)不同;
确认2一CSHI‘为平面t)’ans构型，同时本计算还得到了一个非平面构
型，其能量和最稳定的平面构型的能量很接近;优化得到的2一C6H12十
最稳定构型与以往报道的MPZ的报道的构型不同。(2)计算预言了
环丁烷自由基阳离子的一种新构型，即平行四边形结构，通过改变碳
骨架的二面角，计算的a(H)值能够和实验值很好得吻合。(3)通过
对硫氧分子阴离子大量的理论方法和基组的尝试计算，找到了一种比
较好的计算此类阴离子体系超精细结构的方法。
The present work is the continuous one, closely connected with Dr. Liu Ya-Jun's. The main species studied are included 1-pentene cation (l-C_(5)H_(10)~(+)), 2-pentene cation(2-C_(5)H_(10)~(+)), 1-hexene cationO-C_(6)H_(12)~(+)), 2-hexene(2-C_(6)H_(12)~(+)), 3-hexene(3-C_(6)H_(12)~(+)), cyclobutane cation(c-C_(4)H_(8)+) and bicyclo[2,2,l] hexptane or norbomane and sulfur oxide anions(SO_(2)~(-), SO_(3)~(-) ), Whose molecular structure, electronic states, adibatic electron affinities and spin properties(proton isotropic hyperfme coupling constants a(H) values) have been calculated. Here are several representative ions listed to set forth the research course of the present work.
Hydrocarbon radical cations form a fundamental class of compounds with a variety of intriguing properties and reactivity intermedium in chemistry and biology chemistry. Many chemists have been attaching importance to them. In previous papers there are many research work about the theoretical study of the ethene and propylene cations, which of the hydrocarbon four and more carbon atoms have been rare, otherwise. Lunell and et al carried out ab intio hyperfme structure studies for radical cations of various kinds of hydrocarbon, and they used the (U)HF (Hartree Fock theory) and (U)MP2(second-order unrestricted Moller-Plesset perturbation theory [12,13]) methods in the geometry optimization calculations and the SDCI method for the hyperfme structure (a(H) calculations.
Here density functional theory B3LYP method, together with 6-31G(d,p), 6-31+G(d,p), 6-311G(d,p) and 6-311+G(d,p) basis, has been used. The molecular geometries for various conformations of the pentene and hexene cations have been optimized, and the frequency analysis calculations are performed at the B3LYP/6-311G(d,p) level. The most stable geometries are concluded. l-C_(5)H_(10)~(+) ion is predicted to have a nonplanar structure, which is in contrast to the previous conclusions based on ab initio calculations. At the same time, except for the planar 2-C_(5)H_(10)~(+) , the nonplanar geometry is found, but its
energy is close to the planar one. Based on the B3LYP optimized geometries, the proton isotropic hyperfine coupling constants ( hfcc's ), a(H) values have been calculated at the B3LYP and MP2(full) levels. The calculated isotropic hfcc results of 2-C_(5)H_(10)~(+) and 3-C_(6)H_(12)~(+) are in good agreement with experimental data and more accurate than the previous theoretical results. No experimental hfcc data are available for 1-C_(5)H_(10)~(+), l-C_(6)H_(12)~(+) and 2-C_(6)H_(12)~(+) ions. The hfcc's and the most stable structures for three are predicted in the present work. The potential e0nergy surface of the cyclobutane(c-C_(4)H_(8)) radical cation has been explored at the B3LYP method with all the kinds of standard basis sets. The electron vertical and adiabatic affinities calculations are very near to the experimental data. At B3LYP level the parallelogram and rhombus and rectangle geometries of its radical cation(c-C_(4)H_(8)+) are optimized. It is concluded that the parallelogram geometry, not the thomboidal one, is the most stable one energetically. And the isotropic proton hyperfine coupling constants(a(H)) of pucked parallelogram geometry are in good agreement with experiment.
Sulfur oxide compunds have previously been proposed as important intriguing substances and reactive intermediate in oxidation process. Experimentally, the gas isolated SO_(2)~(-) and SO_(3)~(-) species were reported, together with their molecular structure and hyperfine coupling constants. The adiabatic electron affinities of the corresponding neutral molecules were also determined on the experiment. In the present work the molecular geometries, the proton isotropic hyperfine coupling constants (hfcc) of SO_(2)~(-) and SO_(3)~(-), and the adiabatic electron affinities(AEAs) of the corresponding neutral molecules have been calculated by performinig the quadratic CI calculations including single and double substitutions (QCISD) with the 6-311G(d), 6-311+G(d), 6-311G(2d) and 6
烃类自由基阳离子作为化学反应和生化反应的中间体和引发剂，多年来一直受到理论和实验工作者的重视，许多化学家对它们的分子结构和自旋性质进行过研究。在以往关于烯烃阳离子的理论研究，针对乙烯、丙烯阳离子的较多。文献中关于四个或多于四个碳原子的烯烃阳离子的研究报道较少。Lunell等[1]和Bach等曾用非限制性HF理论、非限制性Moller-Plesset二阶微扰理论(UMP2)和单双激发组态相互作用(SDCI)等方法对1-C_5H_(10)~+，2-C_5H_(10)~+，1-C_6H_(12)~+，2-C_6H_(12)~+和3-C_6H_(12)~+进行了理论计算。本论文使用密度泛函理论B3LYP方法和6-31G(d，p)，6-31+G(d，p)，6-311G(d，p)及6-311+G(d，p)基组，分别对1-C_5H_(10)~+，2-C_5H_(10)~+，1-C_6H_(12)~+，2-C_6H_(12)~+和3-C_6H_(12)~+的各种构象进行了几何构型优化，并用B3LYP／6-311G(d，p)进行了频率分析计算，确定了最稳定构型。计算预言1-C_5H_(10)~+具有非平面陶型，与以往报道的从头算计算结论相反。在各优化构型上，使用B3LYP和MP2(full)方法进行了超精细结构的计算。计算的2-C_5H_(10)~+和3-C_6H_(12)~+的各向同性超精细偶合常数a(H)值比以往的计算结果更好，同时还找到一个非平面的构型，其能量与平面的构型的能量很接近；1-C_5H_(10)~+、1-C_6H_(12)~+和2-C_6H_(12)~+的各向同性超精细偶合常数目前尚无实验数据报道，本计算预言了它们的各向同性超精细偶合常数值a(H)值和最稳定构型。对于环丁烷自由基阳离子，我们用B3LYP方法和各种标准基组研究了它的势能面，得到的电子垂直和绝热亲和势接近
摘要
实验数据。优化得到了平行四边形，菱形和矩形三种构型，而没有得
到梯形的优化构型。所以我们认为具有平行四边形构型的阳离子是最
稳定构型，而不是以前文献报道的梯形构型。固定平行四边形构型碳
骨架二面角，通过部分优化得到构型而计算的各向同性超精细偶合常
数也与实验值吻合得很好。
硫氧化合物在氧化作用中一直被认为是重要的引发剂和中间
体。实验上己经得到了气态游离的二氧化硫和三氧化硫分子的阴离
子，并测得了502一和503一的分子结构和超精细偶合常数值，以及对
应的分子(50:和50;)的绝热电子亲合势(AEA)的实验数据报
道。本论文使用二次组态相互作用(QCISD)方法和6一3 1 10(d)，
6一311+G(d)，6一3llG(Zd)及6一311+G(Zd)基组研究了502一和503一的分
子结构，超精细偶合常数(hfcc)及其对应的分子的绝热电子亲合势
(AEA)。发现在QCISD/6一3 11十G(2d)水平上计算的两个分子离子的
结构，hfcc值(在335和’70上的)和AEA值与实验值符合得都很好
(除503一中的在335上的hfec值比实验值小23%)。作为比较，我
们使用相同基组作了B3LYP方法计算，得到的超精细偶合常数和
AEA值都却与实验符合得不好。
本论文的创新之处在于:(l)计算预一言1一CSH!0一具有非平面构
型，与以往报道的从头算UHF和MPZ等计算结论(平面构型)不同;
确认2一CSHI‘为平面t)’ans构型，同时本计算还得到了一个非平面构
型，其能量和最稳定的平面构型的能量很接近;优化得到的2一C6H12十
最稳定构型与以往报道的MPZ的报道的构型不同。(2)计算预言了
环丁烷自由基阳离子的一种新构型，即平行四边形结构，通过改变碳
骨架的二面角，计算的a(H)值能够和实验值很好得吻合。(3)通过
对硫氧分子阴离子大量的理论方法和基组的尝试计算，找到了一种比
较好的计算此类阴离子体系超精细结构的方法。
The present work is the continuous one, closely connected with Dr. Liu Ya-Jun's. The main species studied are included 1-pentene cation (l-C_(5)H_(10)~(+)), 2-pentene cation(2-C_(5)H_(10)~(+)), 1-hexene cationO-C_(6)H_(12)~(+)), 2-hexene(2-C_(6)H_(12)~(+)), 3-hexene(3-C_(6)H_(12)~(+)), cyclobutane cation(c-C_(4)H_(8)+) and bicyclo[2,2,l] hexptane or norbomane and sulfur oxide anions(SO_(2)~(-), SO_(3)~(-) ), Whose molecular structure, electronic states, adibatic electron affinities and spin properties(proton isotropic hyperfme coupling constants a(H) values) have been calculated. Here are several representative ions listed to set forth the research course of the present work.
Hydrocarbon radical cations form a fundamental class of compounds with a variety of intriguing properties and reactivity intermedium in chemistry and biology chemistry. Many chemists have been attaching importance to them. In previous papers there are many research work about the theoretical study of the ethene and propylene cations, which of the hydrocarbon four and more carbon atoms have been rare, otherwise. Lunell and et al carried out ab intio hyperfme structure studies for radical cations of various kinds of hydrocarbon, and they used the (U)HF (Hartree Fock theory) and (U)MP2(second-order unrestricted Moller-Plesset perturbation theory [12,13]) methods in the geometry optimization calculations and the SDCI method for the hyperfme structure (a(H) calculations.
Here density functional theory B3LYP method, together with 6-31G(d,p), 6-31+G(d,p), 6-311G(d,p) and 6-311+G(d,p) basis, has been used. The molecular geometries for various conformations of the pentene and hexene cations have been optimized, and the frequency analysis calculations are performed at the B3LYP/6-311G(d,p) level. The most stable geometries are concluded. l-C_(5)H_(10)~(+) ion is predicted to have a nonplanar structure, which is in contrast to the previous conclusions based on ab initio calculations. At the same time, except for the planar 2-C_(5)H_(10)~(+) , the nonplanar geometry is found, but its
energy is close to the planar one. Based on the B3LYP optimized geometries, the proton isotropic hyperfine coupling constants ( hfcc's ), a(H) values have been calculated at the B3LYP and MP2(full) levels. The calculated isotropic hfcc results of 2-C_(5)H_(10)~(+) and 3-C_(6)H_(12)~(+) are in good agreement with experimental data and more accurate than the previous theoretical results. No experimental hfcc data are available for 1-C_(5)H_(10)~(+), l-C_(6)H_(12)~(+) and 2-C_(6)H_(12)~(+) ions. The hfcc's and the most stable structures for three are predicted in the present work. The potential e0nergy surface of the cyclobutane(c-C_(4)H_(8)) radical cation has been explored at the B3LYP method with all the kinds of standard basis sets. The electron vertical and adiabatic affinities calculations are very near to the experimental data. At B3LYP level the parallelogram and rhombus and rectangle geometries of its radical cation(c-C_(4)H_(8)+) are optimized. It is concluded that the parallelogram geometry, not the thomboidal one, is the most stable one energetically. And the isotropic proton hyperfine coupling constants(a(H)) of pucked parallelogram geometry are in good agreement with experiment.
Sulfur oxide compunds have previously been proposed as important intriguing substances and reactive intermediate in oxidation process. Experimentally, the gas isolated SO_(2)~(-) and SO_(3)~(-) species were reported, together with their molecular structure and hyperfine coupling constants. The adiabatic electron affinities of the corresponding neutral molecules were also determined on the experiment. In the present work the molecular geometries, the proton isotropic hyperfine coupling constants (hfcc) of SO_(2)~(-) and SO_(3)~(-), and the adiabatic electron affinities(AEAs) of the corresponding neutral molecules have been calculated by performinig the quadratic CI calculations including single and double substitutions (QCISD) with the 6-311G(d), 6-311+G(d), 6-311G(2d) and 6
引文
1. B. Knight, Jr., J.Steadman, D. Feller and E. R. Davidson, J. Am. Chem. Soc.,106(1984) 3700.
2. S. Lunell, M-B. Huang, J.Chem. Soc., Chem, Commun. 1989(1031).
3. ouma, W. J., Poppinger, D., Radom, L. Isr. J. Chem. 23(1983)21.
4. S. Lunell, L. A. Eriksson, M.-B. Huang, J. Mol. Struct.(Theochem.). 230 (1991) 263 (and references therein).
5. M.-B. Huang, S. Lunell, J. Mol. Struct.(Theochem,). 205 (1990) 317 (and references therein).
6. N. Salhi-Benachenhou, B. Engles, M.-B. Huang, S.Lunell, Chem. Phys. 23 (1998) 53.
7. S. Lunell, L.A. Eriksson, L. Worstbrock, J. Am. Chem. Soc. 113 (1991) 7508 (and references therein).
8. S. Lunell, M.-B. Huang, Chem. Phys. Lett. 168 (1990) 63.
9. k.A. Eriksson, and S. Lunell, J.Chem. Soc.,Faraday Trans. 86 (1990) 3287.
10. M.-B. Huang, S.Lunell, J. Chem. Phys. 92(1990)6081.
11. J. W. Gauld, L. A. Eriksson, L. Radom, J. Phys. Chem. 101(1997) 1352.
12. H. Zuihof, J.P. Dinnocenzo, A.C. Reddy, A.Shaik, J. Phys. Chem. 100(1996)15 774
13. L. A. Eriksson, S. Lunell, R. J. Boyd, J. Am. Chem. Soc. 115(1993) 6896.
14. L. A. Eriksson, V. G. Malkin, O. L. Malkina, D. R. Salahub, J. Chem. Phys. 99(1993)9756.
15. L. A. Eriksson, V.G. Malkin, O. L. Malkina, D.R. Salahub, Int. J. Quanturn Chem. 52(1994)879.
16. C. Moller, M.S. Plesset, Phys. Rev. 46(1934).
17. J.A. Pople, J. S. Binkley, R. Seeger, Int. J. Quant, Chem. Symp. 10(1976)1.
18. P. Hohenberg, W. Kohn, Phys. Rev. B 136(1964) 864.
19. W. Kohn, L. J. Sham, Phys. Rev. A140(1965) 1133.
20. A. D. Becke, J. Chem. Phys. 98(1993) 5648.
21. C. Lee, W.Yang, R.G. Parr, Phys. Rev. B37(1988)785.
22. M.-B. Huang, Z.-X. Wang, J. Chem. Phys. 109(1998)8953.
2. S. Lunell, M-B. Huang, J.Chem. Soc., Chem, Commun. 1989(1031).
3. ouma, W. J., Poppinger, D., Radom, L. Isr. J. Chem. 23(1983)21.
4. S. Lunell, L. A. Eriksson, M.-B. Huang, J. Mol. Struct.(Theochem.). 230 (1991) 263 (and references therein).
5. M.-B. Huang, S. Lunell, J. Mol. Struct.(Theochem,). 205 (1990) 317 (and references therein).
6. N. Salhi-Benachenhou, B. Engles, M.-B. Huang, S.Lunell, Chem. Phys. 23 (1998) 53.
7. S. Lunell, L.A. Eriksson, L. Worstbrock, J. Am. Chem. Soc. 113 (1991) 7508 (and references therein).
8. S. Lunell, M.-B. Huang, Chem. Phys. Lett. 168 (1990) 63.
9. k.A. Eriksson, and S. Lunell, J.Chem. Soc.,Faraday Trans. 86 (1990) 3287.
10. M.-B. Huang, S.Lunell, J. Chem. Phys. 92(1990)6081.
11. J. W. Gauld, L. A. Eriksson, L. Radom, J. Phys. Chem. 101(1997) 1352.
12. H. Zuihof, J.P. Dinnocenzo, A.C. Reddy, A.Shaik, J. Phys. Chem. 100(1996)15 774
13. L. A. Eriksson, S. Lunell, R. J. Boyd, J. Am. Chem. Soc. 115(1993) 6896.
14. L. A. Eriksson, V. G. Malkin, O. L. Malkina, D. R. Salahub, J. Chem. Phys. 99(1993)9756.
15. L. A. Eriksson, V.G. Malkin, O. L. Malkina, D.R. Salahub, Int. J. Quanturn Chem. 52(1994)879.
16. C. Moller, M.S. Plesset, Phys. Rev. 46(1934).
17. J.A. Pople, J. S. Binkley, R. Seeger, Int. J. Quant, Chem. Symp. 10(1976)1.
18. P. Hohenberg, W. Kohn, Phys. Rev. B 136(1964) 864.
19. W. Kohn, L. J. Sham, Phys. Rev. A140(1965) 1133.
20. A. D. Becke, J. Chem. Phys. 98(1993) 5648.
21. C. Lee, W.Yang, R.G. Parr, Phys. Rev. B37(1988)785.
22. M.-B. Huang, Z.-X. Wang, J. Chem. Phys. 109(1998)8953.