Subpicosecond transient absorption analysis of the photophysics of 2,2'-bipyridine and 4,4'-bipyridine in solution

被引:92
作者
Buntinx, G
Naskrecki, R
Poizat, O
机构
[1] CNRS,SPECTROCHIM INFRAROUGE & RAMAN LAB,F-94320 THIAIS,FRANCE
[2] POZNAN UNIV,DEPT PHYS,PL-60780 POZNAN,POLAND
关键词
D O I
10.1021/jp960900v
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
The transient absorption spectra of 2,2'-bipyridine (22BPY) and 4,4'-bipyridine (44BPY) following femtosecond excitation at 266 nm in a series of organic solvents have been measured in the 300-670-nm wavelength range with subpicosecond time resolution. The results have been correlated with those obtained in the microsecond time domain. The S-1 states are characterized and attributed to n pi* levels in both molecules. The S-1 state of 22BPY decays essentially via intersystem crossing to the T-1 pi pi* state in all solvents (tau s(1) = 50-80 ps). The 44BPY S-1 lifetime varies from 10 to 70 ps depending on the solvent. The shortest lifetimes are found in alcohols (10-20 ps) and alkanes (approximate to 11 ps) where the fast formation of the N-hydro radical 44BPYH(.), already evidenced in previous nanosecond experiments, is shown to occur with high yields from the S-1 state in parallel to ISC. Ln alcohols this process is found to be activated by the protic character of the solvent and to take place within H-bonded solute/solvent complexes pre-existing in the ground state. A mechanism involving a surprisingly fast H-atom abstraction by the 44BPY S-1 state via homolytic breaking of the alcohol OH bond is suggested.
引用
收藏
页码:19380 / 19388
页数:9
相关论文
共 42 条
[1]   FLUORESCENCE-SPECTRUM OF 2,2'-BIPYRIDINE - THE ROLE OF ASSOCIATE FORMATION AND ROTATIONAL-ISOMERISM [J].
AGRESTI, A ;
BACCI, M ;
CASTELLUCCI, E ;
SALVI, PR .
CHEMICAL PHYSICS LETTERS, 1982, 89 (04) :324-328
[2]   PICOSECOND FLUORESCENCE DECAYS FROM ELECTRONIC EXCITED-STATES OF 2,2'-DIPYRIDINE SOLUTIONS [J].
ANGELONI, L ;
CASTELLUCCI, E ;
SALVI, PR .
JOURNAL OF MOLECULAR STRUCTURE, 1986, 141 :433-436
[3]  
[Anonymous], 1985, ION SOLVATION
[4]   PHOTOREDUCTION OF 4,4'-BIPYRIDINE BY TRIETHYLAMINE AND BY 1,4-DIAZABICYCLO[2.2.2]OCTANE IN ACETONITRILE AS STUDIED BY NANOSECOND ABSORPTION AND RAMAN SPECTROSCOPIES [J].
BUNTINX, G ;
VALAT, P ;
WINTGENS, V ;
POIZAT, O .
JOURNAL OF PHYSICAL CHEMISTRY, 1991, 95 (23) :9347-9352
[5]   TRANSIENT ABSORPTION AND RESONANCE RAMAN STUDIES OF THE PHOTOREDUCTION OF 2,2'-BIPYRIDINE BY AMINES [J].
BUNTINX, G ;
POIZAT, O ;
VALAT, P ;
WINTGENS, V ;
RIGHINI, R ;
FOGGI, P .
JOURNAL DE CHIMIE PHYSIQUE ET DE PHYSICO-CHIMIE BIOLOGIQUE, 1993, 90 (09) :1733-1748
[6]   TRIPLET (T1) STATE AND RADICAL CATION RESONANCE RAMAN INVESTIGATION OF BIPHENYL DERIVATIVES [J].
BUNTINX, G ;
POIZAT, O .
JOURNAL OF CHEMICAL PHYSICS, 1989, 91 (04) :2153-2162
[7]   TRANSIENT ABSORPTION AND RESONANCE RAMAN INVESTIGATION OF THE PHOTOCHEMICAL REACTIVITY OF 2,2'-BIPYRIMIDINE IN SOLUTION [J].
BUNTINX, G ;
POIZAT, O ;
LEYGUE, N .
JOURNAL OF PHYSICAL CHEMISTRY, 1995, 99 (08) :2343-2352
[8]   RAMAN-SPECTROSCOPIC STUDIES OF VIBRATIONAL-RELAXATION AND CHEMICAL-EXCHANGE BROADENING IN HYDROGEN-BONDED SYSTEMS .1. INVESTIGATION OF RELAXATION PROCESSES IN BINARY-MIXTURES OF PYRIDINE AND ETHANOL [J].
CABACO, MI ;
BESNARD, M ;
YARWOOD, J .
MOLECULAR PHYSICS, 1992, 75 (01) :139-155
[9]   Two-photon excitation spectra of the lowest electronic states of 2,2'-bipyridine [J].
CASTELLUCCI, E ;
SALVI, PR ;
FOGGI, P .
CHEMICAL PHYSICS, 1982, 66 (03) :281-291
[10]   MECHANISMS OF DEACTIVATION OF THE LOW-LYING ELECTRONIC STATES OF 2,2'-BIPYRIDINE [J].
CASTELLUCCI, E ;
ANGELONI, L ;
MARCONI, G ;
VENUTI, E ;
BARALDI, I .
JOURNAL OF PHYSICAL CHEMISTRY, 1990, 94 (05) :1740-1745