Polymeric nitrogen donor ligands

Poly-4-vinylpyridine is a versatile polymer since in the non-protonated form it may function as a polymeric nitrogen-donor ligand. Thus, redox centres may be anchored by coordination to pendant 4-pyridyl groups on the polymer chains. 

Metal Ion Binding at Polymeric Nitrogen Donor Ligands... 

One-dimensional coordination polymers based on Ag(I) complexes with aromatic nitrogen-donor ligands have recently been reviewed in [84]. The main focus was on coordination polymers 29 based on Ag(I) cations with Lipyridyl ligands (X = linear, angular or a flexible linker) with various different geometries. The process of coordination polymerization is totally reversible because of the high lability of the Ag-donor atom bond. For example, in the case of Ag(I) complexes with A,A -bis(2-pyridylmethyl)piperazine a onedimensional polymer 30 with a 1 1 composition was obtained. 

Fujita reported a wide range of systems formed by the self-assembly of several nitrogen-donor ligands and palladium and platinum centers.In the assembly of some of these systems, the ternplating properties of anions play an important role. When the square planar complex [Pd(en)2(N03)2] is reacted with l,3,5-rm(4-pyridyl-methyl)benzene in the presence of anionic species having a hydrophobic moiety (such as 4-methoxyphenylacetate), the nearly quantitative formation of the cage structure 9 is observed (see Fig. 3). In the absence of the anionic/ hydrophobic species, this reaction gives rise to a considerable amount of polymeric material. Similarly, the... 

S- and Se-donor ligands. The e.s.r. and electronic spectra of [Co(sacsac)2] and [Co(sacsac)2L] (sacsac = dithioacetylacetonate, L = py or piperidine) have been studied, and a polarographic study of [Co(sacsac)J (n = 2 or 3) in acetone has shown the complexes to have a well-defined capacity to accept one or two electrons in a reversible stepwise manner. The magnitude of the potentials and their reversible nature suggest that isolation of cobalt-sacsac complexes of low formal oxidation states should be possible." Co complexes of l,5-bis-(2-methylmercaptoethylthio)pentane are both hydrated and polymeric, and thermal decomposition in air or nitrogen leads to oxida tion to Co . Ethylenethiourea (etu) and tetramethylthiourea (tmtu) form the complexes [Co(etu) ](N03)2 and [Co(tmtu) ](C10 )2, which are tetrahedral, and [Co(etu)2(N03)2] and [Co(tmtu)2(N03)2] which have distorted octahedral co-ordination. 3-Diphenylphosphinothioyl-l-phenylthiourea, -1,1-diethyl-thiourea, and -1,1-dimethylthiourea form complexes with Co in which the ligands are bidentate. ... 

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