Studies on the non-covalent interactions between cyclodextrins and aryl alkanol piperazine derivatives by mass spectrometry and fluorescence spectroscopy.
The non-covalent complexes of alpha- and beta-cyclodextrins (alpha-, beta-CDs) with two aryl alkanol piperazine derivatives (Pipe I and Pipe II) have been studied by electrospray ionization mass spectrometry (ESI-MS) and fluorescence spectroscopy. The ESI-MS experimental results demonstrated that Pipe I can conjugate to beta-CD and form 1:1 or 1:2 stoichiometric non-covalent complexes, and Pipe II can only form 1:1 complexes with alpha- or beta-CD. Fluorescence spectra indicated that the fluorescence intensities of Pipe I and Pipe II can be enhanced by increasing the content of beta-CD. The mass spectrometric titration experiments showed that the dissociation constants K(d1) were 5.77 and 9.52 x 10(-4) mol L(-1) for the complexes of alpha-CD with Pipe I and Pipe II, respectively, revealing that the binding of alpha-CD-Pipe I was stronger than alpha-CD-Pipe II. The K(d1) and K(d2) values were 9.81 x 10(-4) mol L(-1) and 1.11 x 10(-7) (mol L(-1))(2) for 1:1 and 1:2 complexes of Pipe I with beta-CD, respectively. The K(d) values obtained from fluorescence spectroscopy were in agreement with those from ESI-MS titration.
Chu
Yan-Qiu
YQ
Laser Chemistry Institute, Chemistry Department, Fudan University, Shanghai 200433, China.
Dai
Xin-Hua
XH
Jiang
Dan
D
Jiang
Gong-Yu
GY
Fang
Xiang
X
Ding
Chuan-Fan
CF
D003505:Cyclodextrins / Q000737:chemistry*; D007700:Kinetics; D013058:Mass Spectrometry / Q000379:methods*; D010879:Piperazines / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods
D003505:Cyclodextrins; D010879:Piperazines