267664-37-9Relevant articles and documents
[Ru(II)(hedta)]- complexes of 2,2'-dipyridylamine (dpaH) and a bifunctional tethered analog, N,N,N',N'-tetrakis(2-pyridyl)adipamide (tpada)
Shepherd, Rex E.,Chen, Ya,Kortes, Richard A.,Ward, Matthew S.
, p. 30 - 39 (2000)
[Ru(II)(hedta)L]- complexes (hedta3- = N-hydroxyethylethylenediamine-N,N,N'-triacetate); L = dpaH (2,2'-dipyridylamine) and tpada (N,N,N',N'-tetrakis(2-pyridyl)adipamide)) have been studied by 1H NMR and electrochemical methods in aqueous solution. The bidentate rings of dpaH and tpada are differentiated as shown by NMR upon coordination to Ru(II) due to differences in the local environment. The dpa-R headgroup of each ligand binds 'in-plane' with the en backbone of hedta3- and with one pyridyl ring being nearer the amine of hedta3- having the pendant glycinato group (matching the known arrangement with bpy (2,2'-bipyridine)). Ru(II/III) E(1/2) values follow the order dpaH (0.32 V) a weaker π-acceptor ligand than bpy, and that the withdrawing carbonyl functionality enhances the π-acceptor capacity for the tpada ligand, approaching the stability imparted by bpy. Only the 1:1 [Ru(II)(hedta)(dpaH)]- complex forms even in the presence of excess dpaH. [Ru(II)(hedta)(dpaH)] has a pK(a) of the dipyridylamine proton of approximately 5.0 with [Ru(II)(hedta)(dpa-)] undergoing aquation (k(H2O)= 1.4 10-2 s-1) and OH--assisted dissociation (k(OH) = 1.33 104 M-1 s-1). The {[Ru(II)-(hedta)]2(tpada)}2- complex serves as a water-soluble model as to how {[ML']2(tpada)} complexes might act as an extended bridge between two metal binding sites, potentially those of metallo-derivatized DNA strands, or between one DNA strand and a protein crosslink. In this model M represents an appropriate metal for DNA derivatization such as Ru(II), Pt(II) or Pd(II) and L' represents the attachments to DNA nucleobase sites, aminocarboxylates/peptide coordination for antitumor purposes. (C) 2000 Elsevier Science S.A.
