Bis 1H-benzimidazole Research Articles

Fine tuning of the Cd(II)–bis(benzimidazole) networks by changing carboxylate anions

Three new polymeric frameworks, [Cd(bbbi)(ita)(H2O)] · H2O (1), [Cd(bbbi)(fma)] (2), and [Cd(bbbi)(fma)(H2O)] · 2H2O (3) (bbbi = 1,1-(1,4-butanediyl)bis-1 H-benzimidazole, H2ita = itaconic acid, and H2fma = fumaric acid), have been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction. Complex 1 is a 2-D (4,4) network containing infinite 1-D zigzag Cd(II)-bbbi chains linked by auxiliary ita ligands. In the structure of 2, infinite 1-D linear Cd(II)-bbbi chains are linked by fma ligands to generate an undulated 2-D (4,4) network. In 3, an in situ ligand transformation occurred with malate converted to H2fma by dehydration. Thus, a 2-D (4,4) grid network constructed from bbbi and fma was obtained. The carboxylates with different substituents play an important role in the formation of the final frameworks and coordination modes of Cd(II). Thermal stability and luminescent properties of 1–3 were investigated.

A new compound based on Preyssler-type P5W30 anion modified by CoII and flexible bis(benzimidazole) ligand

Abstract A new Preyssler-type polyoxometalates-based inorganic–organic hybrid compound [Co(Hbbbm)2(H2O)2(H2P5W30O110)]2·9H2bbbm·20H2O ( 1 ) [bbbm = 1,1′-(1,4-butanediyl)bis-1 H-benzimidazole] has been synthesized under hydrothermal conditions and characterized by IR, TG and XRD. Single crystal X-ray diffraction analysis reveals that compound 1 is composed of two Preyssler-type [H2P5W30O110]13− anions (P5W30), two [Co(Hbbbm)2(H2O)2]4+ cations, nine discrete protonated [H2bbbm]2+ molecules and twenty crystallization water molecules. Two P5W30 anions are covalently bridged by two [Co(Hbbbm)2(H2O)2]4+ cationic fragments to form a P5W30-based dimer. The dimers are ultimately extended to a three dimensional (3D) network by π∙∙∙π stacking and hydrogen-bonding interactions. Compound 1 represents the first bisupporting Preyssler-type structure modified by transition metal coordination complex (TMC). Additionally, the electrochemical behavior and electrocatalysis of compound 1 have been investigated.

Impact of counteranion on the self-assembly of Cd(II)-containing MOFs: Syntheses, structures and photoluminescent properties

Three Cd(II)-containing metal–organic frameworks based on 1,1′-(1,5-pentanediyl)bis-1 H-benzimidazole (pbbm), namely, { [ Cd ( NO 3 ) ( pbbm ) 2 ] 2 · ( NO 3 ) 2 · H 2 O } n ( 1 ) , [CdSO 4(pbbm) 2] n ( 2) and [CdI 2(pbbm)] 2 ( 3) are prepared systematically by using hydrothermal technique to examine the effects of counteranion on the topology of the resultant network. In complexes 1 and 2, pbbm acts as a bidentate ligand to link two Cd atoms to result in two different 1D chain structures. Complex 3 has a dimeric structure in which two Cd(II) cations are bridged by two pbbm ligands. The significant differences of these MOFs indicate that the counteranions have great impact on the assembling and structures of the resultant MOFs. The photoluminescent properties of these new materials have been studied in the solid state at room temperature. Further investigation reveals that their photoluminescent characteristics obtained from experiments accord with the computed parameters.

Catalytic applications of Cu II-containing MOFs based on N-heterocyclic ligand in the oxidative coupling of 2,6-dimethylphenol

Two Cu II complexes bearing a N-heterocyclic ligand, namely [Cu(SO 4)(pbbm)] n ( 1) and {[Cu(Ac) 2(pbbm)] · CH 3OH} n ( 2) (pbbm = 1,1′-(1,5-pentanediyl)bis-1 H-benzimidazole) have been synthesized with the aim of exploiting new and potent catalysts. Single crystal X-ray diffraction shows that new polymeric complex 1 features 1-D double-chain framework. The catalytic studies on 1 and 2 indicate that they are efficient homogeneous catalysts for the oxidative coupling of 2,6-dimethylphenol (DMP) to poly(1,4-phenylene ether) (PPE) and diphenoquinone (DPQ) with H 2O 2 as oxidant and NaOMe as co-catalyst at room temperature. Optimal reaction conditions are obtained by examining the effects of solvent, the reaction time, temperature as well as the amounts of co-catalyst, catalyst and oxidant. Under the optimal conditions, the selectivity to PPE is almost up to 90% for both complexes, and the conversion of DMP is 85% for 1 and 90% for 2, comparable to those observed for highly active catalyst systems in the literature. Further comparison of their catalytic performances with those of the corresponding copper salt together with organic ligand, copper salt alone and free ligand reveals that the coordination of ligand to Cu II ion plays a key role in generating the superior reactivities of complexes.

1D helical Zn II metal–organic polymers: Syntheses, structures and fluorescent properties

Hydrothermal reactions of 1,1′-(1,5-pentanediyl)bis-1 H-benzimidazole (pbbm) with ZnCl 2 afford two 1D helical metal–organic polymers {[ZnCl 2(pbbm)] · (H 2O) 1/8} n ( 1) and {[Zn(pbbm) 2] · Cl 2 · (H 2O) 1/2} n ( 2). Polymer 1 features a 1D single helical architecture, whereas 2 possesses a 1D cationic double helical chain framework. Photoluminescence investigations reveal that both of them display strong emissions in the solid state at room temperature, which could originate from a ligand-to-ligand charge-transfer (LLCT) transition, as confirmed by the molecular orbital (MO) calculations.

Adaptable metal cluster block: Facile construction of photoluminescent CuI coordination polymeric clusters with metal (I) iodides

Solution reaction of Cu(I) iodide with organic multifunctional ligands generated two different structure motifs: 0D cluster [(CuI) 2(dpds) 2] 1 (dpds = 2,2′-dipyridyldisulfide), and 1D polymer [(CuI)(bbbm)] n 2 (bbbm = 1,1′-(1,4-butanediyl)bis-1 H-benzimidazole). Both compounds contain the flexible rhomboid Cu 2I 2 cluster unit. The solution-state luminescence spectra showed that the high-energy emission may be associated with a metal-to-ligand [Cu → π ∗(pyridine)] or ligand-to-ligand [I − → π ∗(pyridine)] charge-transfer excited state.

A novel helical chain zinc(II) coordination polymer derived from both ferrocenecarboxylato and bibenzimidazolyl ligands: synthesis, crystal structure and properties

A novel zinc(II) coordination polymer {[Zn(FcCOO) 2(bbbm)]·2H 2O} n (Fc=( η 5–C 5H 5)Fe( η 5–C 5H 4); bbbm=1,1′-(1,4-butanediyl)bis-1 H-benzimidazole) was obtained by the reaction of Zn(OAc) 2·2H 2O with bbbm and FcCOONa in methanol solution. The molecule reveals an infinite one-dimensional (1D) helical chain [Zn(bbbm)] n with the ferrocenecarboxylate anion as monodentate coordinating to the Zn ion. Its thermal and electrochemical properties were also investigated.