Coordination polymers benzimidazoles

When benzimidazole acts as a corrosion inhibitor for copper this involves formation of a coordination polymer which results from aerial oxidation of the initial benzimidazole-Cu" complex to give a film of bis-benzimidazolatocopper + (51) on the metal surface <89JCS(P2)33>. 

Liu JC, Cao J, Deng WT, Chen BH. Synthesis, crystal structure, photoluminescent, and electrochemical properties of a novel 2-D silver(I) coordination polymer with lH-l,2,4-triazole-1 -methylene-1 H-benzimidazole-1 -acetic acid. J Chem Crystallogr 2011 41(6) 806-10. 

Polymers containing benzimidazole units in their backbones have also been used in the synthesis of coordination metallopolymers (159-162). Osmium and ruthenium coordinated polymers with bipyridine ligands have been prepared (159,160). These polymers (72, 73) possessed metal-metal interactions through their conjugated backbones. Communication between the ruthenium centers of 72 increased by deprotonating the imidazole protons (160). The osmium coordinated polymer (73) showed two reduction waves separated by 0.32 V, indicative of strong cnmmimication between the Os centers (159). 

Sun Y-G, Yu W, Wang L et al (2010) Synthesis, structures, and luminesctaice of lanthanide coordination polymers constructed from benzimidazole-5,6-dicarboxylate and oxalate ligands. Inorg Chem Commun 13 479-483... 

It is worth noting that the coordination unit MNO is present in layer polymers containing fragments of deprotonated nitrylnitroxyl radicals, which have an imidazole or benzimidazole substituent in the position 2, as shown by structure 450 [790] ... 

Polymers 250 and 251, formed by coordination of Ru11 complexes to the preformed 2,6-poly(bis(benzimidazol-2-yl)pyridine), showed a strong enhancement of absorption and photosensitivity in the visible region relative to the unmetalated polymer.141 The metalated polymers, with ca. 90% of the coordination sites occupied, showed an inherent viscosity of 1.8 dLg-1. Although the polymers have low conductivities (ca. 10 10Scm-1), they exhibited higher photocurrents than the organic precursor polymer. 

A photoactive metal center is introduced in these systems. The ruthenium bipyridyl complexes are coordinated to the emeraldine base to form the corresponding polymer complexes as described above." The incorporation of the ruthenium centers to the pyridyl backbone has been also reported to give the ruthenium complexes Conjugated ruthenium bipyridine complexes thus obtained are evaluated to be photorefractive materials. Other transition metal complexes can be employed to form the corresponding polymer complexes. The pyridine unit is replaced by bithienyl, 1,4-diazabutadiene, ethylene, benzimidazole or thiazole. ... 

Wei Y, Yu Y, Wu K (2008) Highly stable live-coordinated Mn(II) polymer [Mn(hbidc)]n (hbidc = lH-benzimidazole-5,6-dicarboxylate) crystal structure, antiferromegnetic property, and strong Icnig-lived luminescence. Cryst Growth Des 8 2087-2089... 

A conjugated polymer that contains a tridentate 2,6- )w(benzimidazol-2-yljpyridine ligand coordinated to ruthenium has also been synthesized by Chan et al. (Scheme 20). ° Reaction of polymer 83 with 2,6-Z)i5 (benzimidazol-2-yl)pyridine ruthenium trichloride formed polymer 84. The complexation reactions were greater than 90% successful according to elemental analyses. While polymer 83 was luminescent, its ruthenium complexed form (84) was not luminescent because of photodissociation of the terminal benzimidazole... 

In a wide definition, PBI refers to a large family of aromatic heterocyclic polymers containing benzimidazole units. PBI with different structures can be synthesized from hundreds of combinations of tetraamines and diacids. In a specific way, PBI refers to the commercial product under the trademark Celazole , poly(2,2 -m-(phenylene)-5,5 -bibenzimidazole) (Fig. 4.1). In the context of PBI with different structures, this specific PBI is also named as meia-PBI because phenylene ring is meto-coordinated. As an amorphous thermoplastic polymer, the aromatic nuclei of PBI provide the polymer high thermal stabihty (glass transition temperature, Fg = 425-436 °C), excellent chemical resistance, retention of stiffness and toughness, but poor process-abihty [56-58]. Primarily used in textile fibers, the selection of poly(2,2 -m-(phenyl-ene)-5,5 -bibenzimidazole) as the commercial product was made on the basis of its... 

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