Thermal and solvent effects on the triplet formation in cinnoline

被引:62
作者
Etinski, Mihajlo [1 ]
Tatchen, Joerg [2 ]
Marian, Christel M. [2 ]
机构
[1] Univ Belgrade, Fac Phys Chem, Belgrade 11158, Serbia
[2] Univ Dusseldorf, Inst Theoret & Computat Chem, D-40225 Dusseldorf, Germany
关键词
GAUSSIAN-BASIS SETS; ABSORPTION-SPECTRA; ELECTRONIC-SPECTRA; LARGE MOLECULES; RESOLUTION; STATE; AZANAPHTHALENES; MODES; RAMAN;
D O I
10.1039/c3cp53247j
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
Cinnoline (1,2-diazanaphthalene) is of particular interest among the diazanaphthalenes. Its triplet quantum yield upon photoexcitation depends strongly on the temperature and the solvent environment. At the beginning of this study, the properties of the lowest triplet electronic state were not understood either. To elucidate the photophysics of cinnoline, we implemented algorithms based on the time-dependent approach for calculating intersystem crossing rates and one-photon spectra of thermally equilibrated vibronic levels. Our quantum chemical investigations reveal that the triplet formation in hydrocarbon solutions at low temperatures is an El-Sayed forbidden process. At higher temperatures and in hydroxylic solutions an additional El-Sayed allowed channel opens up, increasing the intersystem crossing rate substantially. Furthermore, we have solved the old puzzle concerning the character of the lowest triplet state of cinnoline. In the gas phase the electronic structure has mainly n pi(*) character with additional contributions from pi pi(*) configurations since the nuclear arrangement in the pyridazine ring is not planar. In hydroxylic solvents, the electronic structure of the T-1 state is altered. The simulation of the triplet emission shows that the experimentally observed phosphorescence of cinnoline in ethanol most certainly stems from the (3)(pi pi(*)) emission.
引用
收藏
页码:4740 / 4751
页数:12
相关论文
共 53 条
[1]  
[Anonymous], 1996, AMFI IS ATOMIC SPIN
[2]   DENSITY-FUNCTIONAL THERMOCHEMISTRY .3. THE ROLE OF EXACT EXCHANGE [J].
BECKE, AD .
JOURNAL OF CHEMICAL PHYSICS, 1993, 98 (07) :5648-5652
[3]   THE 2ND-ORDER APPROXIMATE COUPLED-CLUSTER SINGLES AND DOUBLES MODEL CC2 [J].
CHRISTIANSEN, O ;
KOCH, H ;
JORGENSEN, P .
CHEMICAL PHYSICS LETTERS, 1995, 243 (5-6) :409-418
[4]   Spin-orbit coupling patterns induced by twist and pyramidalization modes in C2H4:: A quantitative study and a qualitative analysis [J].
Danovich, D ;
Marian, CM ;
Neuheuser, T ;
Peyerimhoff, SD ;
Shaik, S .
JOURNAL OF PHYSICAL CHEMISTRY A, 1998, 102 (29) :5923-5936
[6]  
Duschinsky F, 1937, ACTA PHYSICOCHIM URS, V7, P551
[7]   TRIPLET STATE - ITS RADIATIVE AND NONRADIATIVE PROPERTIES [J].
ELSAYED, MA .
ACCOUNTS OF CHEMICAL RESEARCH, 1968, 1 (01) :8-&
[8]   ENERGY GAP LAW FOR RADIATIONLESS TRANSITIONS IN LARGE MOLECULES [J].
ENGLMAN, R ;
JORTNER, J .
MOLECULAR PHYSICS, 1970, 18 (02) :145-+
[9]   Time-dependent approaches for the calculation of intersystem crossing rates [J].
Etinski, Mihajlo ;
Tatchen, Joerg ;
Marian, Christel M. .
JOURNAL OF CHEMICAL PHYSICS, 2011, 134 (15)
[10]   Overruling the energy gap law: fast triplet formation in 6-azauracil [J].
Etinski, Mihajlo ;
Marian, Christel M. .
PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 2010, 12 (48) :15665-15671