[Investigation on the molecular structures and electronic absorption spectra of Tanshinone II A and Tanshinone II A -Cu(II) complex].

Using an intensified spectroscopic detector CCD,the UV-Vis absorption spectra of tanshinone ⅡA and Tanshinone ⅡA-Cu(Ⅱ) complex were acquired.The stable geometric structures of Tanshinone ⅡA and TanshinoneⅡA-Cu(Ⅱ) complex were obtained by using density functional theory method.Based on the optimized geometric structures,the electronic absorption spectra of Tanshinone ⅡA and TanshinoneⅡA-Cu(Ⅱ) complex in gas phase and in ethanol solution were calculated by using time-dependent density functional theory.Results show that the solvent effect induces the red shift of spectrum for Tanshinone ⅡA and the blue shift of spectrum for Tanshinone ⅡA-Cu(Ⅱ) complex.The calculated absorption spectra including the solvent effect are in good agreement with the experimental results.The present work first measured and computed the electronic absorption spectra of Tanshinone ⅡA-Cu(Ⅱ) complex.