US EPA

7744756 

Journal Article 

PHOTOPHYSICS OF A STERICALLY CROWDED TERTIARY-SATURATED AMINE - TRIISOPROPYLAMINE 

Halpern, AM; Ramachandran, BR 

1992 

1 

Journal of Physical Chemistry
ISSN: 0022-3654 

96 

24 

9832-9839 

English 

10.1021/j100203a047 

WOS:A1992KA29800047 

The spectroscopic and photophysical properties of triisopropylamine (TIPA), a sterically overcrowded amine, are reported in the vapor phase and in n-hexane and tetrahydrofuran solution. On the basis of available experimental data and several semiempirical and ab initio quantum mechanical calculations, it is concluded that TIPA is planar or nearly planar in the ground state. Inversion barriers of NH3, trimethylamine, and TIPA are examined with the aid of computational methods. In the vapor phase, E00 and Evert are 36550 and 38000 cm-1, respectively, for the S0 → S1 transition. The zero-pressure-extrapolated fluorescence lifetime and quantum efficiency are 57.8 ns and 0.79, respectively. Its properties are compared with other tri-C3-substituted amines, such as tri-n-propylamine (TNPA) and the cage amine, 1-azabicyclo[3.3.3]undecane (ABCU). As compared with TNPA, the S0 → S1 absorption of TIPA is red shifted and its Stokes shift is smaller. The cage structure of ABCU results in the S0 ↔ S1 transitions being very vertical. Multielectron configuration interaction calculations using MNDO are used to determine the E00 and Evert values of the amines; the results are compared with experiment. © 1992 American Chemical Society.