Synthesis and binding properties of hybrid cyclophane-azamacrocyclic receptors.
Three new azamacrocyclic-cyclophane hybrid receptors L(1), L(2), and L(3) have been synthesized that incorporate either 1,4,7,10-tetraazacyclododecane (cyclen) or 1,4,7-triazacyclononane (tacn) unit(s) tethered via a short amidic spacer to an electron donor and a H-bonding crown ether polycycle. The crown ether is designed to act as a host toward biologically relevant guests, whereas the macrocycle can coordinate a zinc(II) or a copper(II) ion. The pK(a) of this bound water in the zinc(II) complex of L(1) and L(2) is approximately 7.5. Isothermal calorimetry experiments carried out on [ZnL(1)(L2)(OH(2))](CF(3)SO(3))(2) and [Zn(2)L(2)(OH(2))(2)](CF(3)SO(3))(4) in buffered water (pH 7.4) at 25 degrees C show that the host strongly binds a series of phosphate derivatives. In comparison, the complex [CuL(3)(OH(2))(2)](CF(3)SO(3))(2) is a poor receptor toward phosphate substrates.
Benniston
Andrew C
AC
Molecular Photonics Laboratory, School of Natural Sciences (Chemistry), Bedson Building, University of Newcastle, Newcastle upon Tyne NE1 7RU, UK. A.C.Benniston@ncl.ac.uk
Gunning
Patrick
P
Peacock
Robert D
RD
D002384:Catalysis; D003300:Copper / Q000737:chemistry*; D043844:Crown Ethers / Q000138:chemical synthesis*; D007700:Kinetics; D008024:Ligands; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis*; D015032:Zinc / Q000737:chemistry*
D043844:Crown Ethers; D008024:Ligands; D009942:Organometallic Compounds; D003300:Copper; D015032:Zinc