The interaction of the complex[Cu 2 Cl 4 (C 17 H 20 Cl 2 N 2 ) 2 ] with bovine serum albumin (BSA) has been investigated by fluorescence spectroscopy and UV-absorption under simulative physiological conditions. The experimental results indicated that the quenching mechanism of fluorescence of BSA by complex was a static quenching process. The binding constants(K a ) and the number of binding sites(n) were calculated ; The thermodynamic parameters. the enthalpy change (ǻH) and the entropy change (ǻS) were calculated to be -13.01kJ/mol, 13.35 kJ/mol respectively, which indicated that the interaction between complex and BSA was driven, mainly by electrostatic force. The negative sign for Gibbs free energy (ǻG = -89.98 kJ/mol) means that the interaction process is spontaneous. The binding distance between complex and BSA was calculated to be 3.79 nm on the EDVLV RI WKH )ĘVWHU ¶V WKHRU\, which indicates the energy transfer from BSA to complex can occur. The synchronous fluorescence and UV-absorption of BSA showed that complex could change the conformation of BSA.

Key indicators: single-crystal X-ray study; T = 298 K; mean (C-C) = 0.005 Å; R factor = 0.057; wR factor = 0.188; data-to-parameter ratio = 13.2.In the title compound, C 18 H 14 O 4 ÁC 2 H 6 O, the coumarin ring system is approximately planar with a maximum deviation of 0.037 (3) Å and is nearly perpendicular to the benzene ring, making a dihedral angle of 86.55 (9) . In the crystal, molecules are linked by classical O-HÁ Á ÁO hydrogen bonds and weak C-HÁ Á ÁO interactions. Related literature