Premium
ATP Recognition Through a Fluorescence Change in a Multicomponent Dinuclear System Containing a Ru(Tpy) 2 2+ Fluorescent Core and a Cyclam−Cu 2+ Complex
Author(s) -
PadillaTosta Miguel E.,
Lloris José Manuel,
MartínezMáñez Ramón,
Pardo Teresa,
Sancenón Felix,
Soto Juan,
Marcos M. Dolores
Publication year - 2001
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/1099-0682(200105)2001:5<1221::aid-ejic1221>3.0.co;2-#
Subject(s) - cyclam , chemistry , fluorescence , bioinorganic chemistry , stereochemistry , photochemistry , metal , organic chemistry , physics , quantum mechanics
The Cu 2+ complex of the ligand L 1 (L 1 = [Ru(tpycyclam)(mtpy)] 2+ , tpycyclam = 1‐[4′‐ p ‐tolyl‐(2,2′:6′,2′′‐terpyridyl)]‐1,4,8,11‐tetraazacyclotetradecane and mtpy = 4′‐methyl‐2,2′:6′,2′′‐terpyridine) is able to display a selective sensing response against anions such as ATP. The L 1 −Cu 2+ system contains a Ru(tpy) 2 2+ fluorescent core and a cyclam−Cu 2+ subunit. The fluorescent response of the Ru(tpy) 2 2+ core in an aqueous environment (acetonitrile/water, 70:30) is governed by the quenching produced by the Cu 2+ cation. In the presence of anions the L 1 −Cu 2+ system shows a rich emission fluorescent response. Electrochemical studies on the Cu(cyclam) 2+ complex in propylene carbonate in the presence of certain anions allowed us to conclude that the interaction with the anions sulfate, phosphate, ATP, ADP and GMP is mainly electrostatic whereas chloride and bromide form axial covalent bonds with the copper atom in the Cu(cyclam) 2+ complex. The addition of anions that coordinate at the axial positions of the square‐planar Cu 2+ −cyclam subunit (such as Cl − , Br − and OH − ) produced an enhancement of the emission intensity. This enhancement is attributed to the occupation of the apical positions of copper in the Cu 2+ −L 1 complex that might reduce the probability of an interaction between the Cu 2+ ions and the Ru(tpy) 2 2+ groups reducing the quenching process and, consequently, resulting in an enhancement of the fluorescence. A prediction of the fluorescent behaviour with the anions sulfate, phosphate, ATP, ADP and GMP that give electrostatic interactions with the positively charged cyclam−Cu 2+ and/or Ru(tpy) 2 2+ centres is rather difficult. Potentiometric studies on the L 1 −Cu 2+ −H + −ATP system suggested that the [Cu(L 1 )(ATP)] complex is responsible for the quenching observed at basic pH in the presence of ATP. It is noticeable that the quenching of the intensity of the fluorescence due to ATP in the pH range 9 to 10 is selective and no other anion studied is able to quench the emission of the Ru(tpy) 2 2+ core in this pH range.