A conformationally flexible dinuclear Pt(II) complex with differential behavior of its two states toward quadruplex DNA.
Chemistry
; 19(34): 11429-38, 2013 Aug 19.
Article
em En
| MEDLINE
| ID: mdl-23852779
ABSTRACT
The reaction of tetrakis(pyridine-2-yl)pyrazine (tppz) with 2â
equiv of (2,2'-bpy)Pt(II) in water yields two isomeric dinuclear cations, [{Pt(2,2'-bpy)}2 (tppz)](4+) , in which Pt coordination exclusively takes place through the two pairs of pyridine-2-yl nitrogen atoms. The two conformational isomers differ in their overall shape, with the formation of "Z" and "U" shapes, which are formed at 40 °C (Z isomer, 1) and under reflux conditions (U isomer, 2), respectively. X-ray crystal-structure analyses of the Zâ
isomer, [{Pt(2,2'-bpy)}2 (tppz)](PF6 )4 â
3 CHCl3 â
4 H2 O (1 a), and of the Uâ
isomer, [{Pt(2,2'-bpy)}2 ](PF6 )4 â
2 CH3 CNâ
1.5 H2 O (2 a), were carried out. Co-crystallization of compound 2 with PtCl2 (2,2'-bpy) yielded [{Pt(2,2'-bpy)}2 (tppz)](BF4 )4 â
[PtCl2 (2,2'-bpy)]â
4.5 H2 O (3), in which the PtCl2 (2,2'-bpy) entity was sandwiched between the two 2,2'-bpy faces of the U-shaped cation (2). Quantum chemical calculations revealed that the Uâ
isomer was more stable than the Zâ
isomer, both in the gas phase and in an aqueous environment. These two isomers display different affinities toward duplex DNA and human telomeric quadruplex DNA (Htelo), as concluded from CD spectroscopy and FID assays. Thus, the Uâ
isomer binds significantly more strongly to quadruplex DNA (DC50 =0.38â
µM) than the Zâ
isomer (DC50 =8.50â
µM).
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Platina
/
Quadruplex G
/
Complexos de Coordenação
Limite:
Humans
Idioma:
En
Revista:
Chemistry
Assunto da revista:
QUIMICA
Ano de publicação:
2013
Tipo de documento:
Article
País de afiliação:
Alemanha