title: Nucleic acid intercalators and avidin probes derived from luminescent cyclometalated iridium(III)-dipyridoquinoxaline and -dipyridophenazine complexes.
abstract: Six luminescent cyclometalated iridium(III)-dipyridoquinoxaline and -dipyridophenazine complexes [Ir(ppy)2(N-N)](PF6) (Hppy = 2-phenylpyridine; N-N = dipyrido[3,2-f:2',3'-h]quinoxaline, dpq (1); 2-n-butylamidodipyrido[3,2-f:2',3'-h]quinoxaline, dpqa (2); 2-((2-biotinamido)ethyl)amidodipyrido[3,2-f:2',3'-h]quinoxaline, dpqB (3); dipyrido[3,2-a:2',3'-c]phenazine, dppz (4); benzo[i]dipyrido[3,2-a:2',3'-c]phenazine, dppn (5); 11-((2-biotinamido)ethyl)amidodipyrido[3,2-a:2',3'-c]phenazine, dppzB (6)) have been designed as luminescent intercalators for DNA and probes for avidin. The structure of complex 4 has been studied by X-ray crystallography. The photophysical and electrochemical properties of the complexes have also been investigated. The binding of these complexes to double-stranded calf thymus DNA and synthetic double-stranded oligonucleotides poly(dA) x poly(dT) and poly(dG) x poly(dC) has been investigated by spectroscopic titrations. The interactions between the two biotin-containing complexes and avidin have been studied by 4'-hydroxyazobenzene-2-carboxylic acid (HABA) assays and emission titrations.
authors.affiliation: Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, People's Republic of China. bhkenlo@cityu.edu.hk
authors.forename: Kenneth Kam-Wing
authors.initials: KK
authors.lastname: Lo
authors.forename: Chi-Keung
authors.initials: CK
authors.lastname: Chung
authors.forename: Nianyong
authors.initials: N
authors.lastname: Zhu
mesh_terms: D001360:Avidin / Q000737:chemistry*; D001391:Azo Compounds / Q000737:chemistry; D018360:Crystallography, X-Ray; D004247:DNA / Q000737:chemistry; D005456:Fluorescent Dyes / Q000737:chemistry; D007364:Intercalating Agents / Q000737:chemistry*; D007495:Iridium / Q000737:chemistry*; D015335:Molecular Probes / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D010619:Phenazines / Q000737:chemistry*; D011810:Quinoxalines / Q000737:chemistry*; D013050:Spectrometry, Fluorescence
chemical_list: D001391:Azo Compounds; D005456:Fluorescent Dyes; D007364:Intercalating Agents; D015335:Molecular Probes; D009942:Organometallic Compounds; D010619:Phenazines; D011810:Quinoxalines; D001360:Avidin; C001413:HABA; D007495:Iridium; D004247:DNA; C427203:calf thymus DNA