原子与分子物理学报
原子與分子物理學報
원자여분자물이학보
CHINESE JOURNAL OF ATOMIC AND MOLECULAR PHYSICS
2015年
4期
572-578
,共7页
何云清%胡启山%胡文%刘柳斜
何雲清%鬍啟山%鬍文%劉柳斜
하운청%호계산%호문%류류사
白藜芦醇%异构体%三重态%自然键轨道%前线轨道%UV
白藜蘆醇%異構體%三重態%自然鍵軌道%前線軌道%UV
백려호순%이구체%삼중태%자연건궤도%전선궤도%UV
Resveratrol%Isomers%Triplet state%Natural bond orbital (NBO)%Frontier orbital%UV
在B3LYP/6-311++G( d,p)水平对白藜芦醇顺反异构体及第一三重激发态进行了结构优化、频率计算和自然键轨道( Natural Bond Orbital,NBO)分析.在MP2/6-311++G( d,p)//B3LYP/6-311++G ( d,p)水平比较了白藜芦醇顺反异构体的能量.反式白藜芦醇整个分子呈平面结构,顺式白藜芦醇两苯环之间存在约30 o扭角.第一三重激发态中两苯环几乎处于互相垂直的关系,C7-H5与C8-H6键也是几乎互相垂直的关系.顺式和反式白藜芦醇C7-C8的σ键成键情况分别为sp1.53-sp1.53和sp1.59-sp1.60,C7与C8各自提供p轨道形成π键,即形成C7=C8双键.三重态中,C7-C8的成键情况为sp1.92-sp1.89,没有p-pπ键,C7、C8均还有一个2p轨道未参与杂化,NBO分析证实C7、C8的各自剩下的2p轨道均几乎独立形成了高能量的反键轨道,分别垂直于单羟基和双羟基苯环,C7-C8键长明显长于白藜芦醇顺反异构体.顺式白藜芦醇比反式白藜芦醇的自由能高约1.3-2.5 kcal/mol,反式构型是热力学稳定构型.含时密度泛函方法(Time-Dependent Density Functional Theory,TD-DFT)方法,B3LYP/6-311++G(d,p)水平计算得反式和顺式白藜芦醇最强紫外吸收峰分别在330 nm和319 nm.
在B3LYP/6-311++G( d,p)水平對白藜蘆醇順反異構體及第一三重激髮態進行瞭結構優化、頻率計算和自然鍵軌道( Natural Bond Orbital,NBO)分析.在MP2/6-311++G( d,p)//B3LYP/6-311++G ( d,p)水平比較瞭白藜蘆醇順反異構體的能量.反式白藜蘆醇整箇分子呈平麵結構,順式白藜蘆醇兩苯環之間存在約30 o扭角.第一三重激髮態中兩苯環幾乎處于互相垂直的關繫,C7-H5與C8-H6鍵也是幾乎互相垂直的關繫.順式和反式白藜蘆醇C7-C8的σ鍵成鍵情況分彆為sp1.53-sp1.53和sp1.59-sp1.60,C7與C8各自提供p軌道形成π鍵,即形成C7=C8雙鍵.三重態中,C7-C8的成鍵情況為sp1.92-sp1.89,沒有p-pπ鍵,C7、C8均還有一箇2p軌道未參與雜化,NBO分析證實C7、C8的各自剩下的2p軌道均幾乎獨立形成瞭高能量的反鍵軌道,分彆垂直于單羥基和雙羥基苯環,C7-C8鍵長明顯長于白藜蘆醇順反異構體.順式白藜蘆醇比反式白藜蘆醇的自由能高約1.3-2.5 kcal/mol,反式構型是熱力學穩定構型.含時密度汎函方法(Time-Dependent Density Functional Theory,TD-DFT)方法,B3LYP/6-311++G(d,p)水平計算得反式和順式白藜蘆醇最彊紫外吸收峰分彆在330 nm和319 nm.
재B3LYP/6-311++G( d,p)수평대백려호순순반이구체급제일삼중격발태진행료결구우화、빈솔계산화자연건궤도( Natural Bond Orbital,NBO)분석.재MP2/6-311++G( d,p)//B3LYP/6-311++G ( d,p)수평비교료백려호순순반이구체적능량.반식백려호순정개분자정평면결구,순식백려호순량분배지간존재약30 o뉴각.제일삼중격발태중량분배궤호처우호상수직적관계,C7-H5여C8-H6건야시궤호호상수직적관계.순식화반식백려호순C7-C8적σ건성건정황분별위sp1.53-sp1.53화sp1.59-sp1.60,C7여C8각자제공p궤도형성π건,즉형성C7=C8쌍건.삼중태중,C7-C8적성건정황위sp1.92-sp1.89,몰유p-pπ건,C7、C8균환유일개2p궤도미삼여잡화,NBO분석증실C7、C8적각자잉하적2p궤도균궤호독립형성료고능량적반건궤도,분별수직우단간기화쌍간기분배,C7-C8건장명현장우백려호순순반이구체.순식백려호순비반식백려호순적자유능고약1.3-2.5 kcal/mol,반식구형시열역학은정구형.함시밀도범함방법(Time-Dependent Density Functional Theory,TD-DFT)방법,B3LYP/6-311++G(d,p)수평계산득반식화순식백려호순최강자외흡수봉분별재330 nm화319 nm.
The geometry optimizations, vibration frequencies, and natural bond orbital ( NBO) analysis of cis/trans-resveratrol and the first triplet state were performed at B3LYP/6-311++G( d,p) level, free energies of two isomers were obtained at B3LYP /6-311++G( d,p)//B3LYP/6-311++G( d,p) level.Trans-res-veratrol is a planar structure, a torsional angle of benzene rings of cis-resveratrol is about 30o.One benzene ring of the first triplet state is perpendicular to the other, and C7-H5 bond is perpendicular to C8-H6.C7-C8 σbonds in cis/trans-resveratrol are sp1.53 -sp1.53 and sp1.59 -sp1.60 , respectively, and a πbond is formed using p orbital from C7 and C8.C7-C8 in the triplet state is sp1.92 -sp1.89σbond, 2p orbital of C7 or C8 forms one high energy antibonding orbital independently, and similar to C8, and is perpendicular to the benzene ring with one hydroxy and two hydroxies, respectively, with its C7-C8 bond length longer than that in cis/trans-resveratrol.Trans-resveratrol is the thermodynamic stable structure because its free energy is lower than that of cis -resveratrol 1.3 -2.5 kcal/mol.The strongest ultraviolet absorption peaks of trans -and cis -resveratrol areat 330 nm and 319 nm, respectively, achieved at B3LYP/6 -311 ++G(d,p) level using TD -DFT method.