Pramanik Rajib, Rao Vishal Govind, Sarkar Souravi, Ghatak Chiranjib, Setua Palash, Sarkar Nilmoni
Department of Chemistry, Indian Institute of Technology, Kharagpur, WB, India.
J Phys Chem B. 2009 Jun 25;113(25):8626-34. doi: 10.1021/jp900627h.
The dynamics of solvent and rotational relaxation of coumarin 153 (C-153) has been studied in neat N,N,N-trimethyl-N-propyl ammonium bis(trifluoromethanesulfonyl) imide ([N(3111)][Tf(2)N]) and its mixtures with polar solvents, namely, methanol and acetonitrile at three different temperatures from 294 to 303 K. Both the solvent and rotational relaxation dynamics of C-153 in neat [N(3111)][Tf(2)N] are linearly correlated with the bulk viscosity at different temperatures. The solvent relaxation time and rotational relaxation time of C-153 decrease with gradual addition of cosolvents in [N(3111)][Tf(2)N]. The gradual addition of cosolvent decreases the viscosity of the medium, and consequently, the solvation and rotational relaxation time also decrease. The decrease of solvation time is more pronounced on addition of acetonitrile compared to methanol.
已在纯N,N,N-三甲基-N-丙基铵双（三氟甲磺酰）亚胺（[N(3111)][Tf(2)N]）及其与极性溶剂（即甲醇和乙腈）的混合物中，于294至303 K的三个不同温度下研究了香豆素153（C-153）的溶剂动力学和旋转弛豫。在纯[N(3111)][Tf(2)N]中，C-153的溶剂弛豫动力学和旋转弛豫动力学在不同温度下均与本体粘度呈线性相关。随着在[N(3111)][Tf(2)N]中逐渐加入共溶剂，C-153的溶剂弛豫时间和旋转弛豫时间会降低。共溶剂的逐渐加入会降低介质的粘度，因此，溶剂化和旋转弛豫时间也会降低。与甲醇相比，加入乙腈时溶剂化时间的降低更为明显。
