Intramolecular charge transfer in 1:1 Cu(II)/pyrenylcyclam dendrimer complexes.
Two newly synthesized pyrenylcyclam dendrons (1 and 2) exhibit a new emission band centered at 450 nm when coordinated with copper triflate. Observed fluorescence shifts induced by coordinative metalation indicate an unusual intramolecular charge transfer from a pyrenyl excited state to the coordinated metal ion that competes with pyrene excimer formation. This interaction likely proceeds by photoexcitation of pi-complex of the appended arene, followed by intramolecular charge transfer within the dendritic 1:1 cyclam/metal complex, effecting reduction of the bound Cu(II) metal ion. The appended dendritic groups not only decrease the equilibrium binding constant with Cu(II) but also participate in a new excited-state pathway as an alternative to energy-dissipative excimer formation.
Gu
Tao
T
Department of Chemistry and Biochemistry, University of California at San Diego, La Jolla, California 92093-0358, USA.
Whitesell
James K
JK
Fox
Marye Anne
MA
D003300:Copper / Q000737:chemistry*; D050091:Dendrimers / Q000737:chemistry*; D047029:Lactams, Macrocyclic / Q000737:chemistry*; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*
D050091:Dendrimers; D047029:Lactams, Macrocyclic; D009942:Organometallic Compounds; D003300:Copper