Cobalt(II) and Copper(II) Complexes Constructed from Bis(benzimidazole) and 2,6‐Pyridinedicarboxylate Co‐ligands: Synthesis, Crystal Structures, and Catalytic Properties

Abstract

Three metal complexes based on the flexible bis(benzimidazole) derivatives, namely [Co 2 (L1) 4 (pydc) 2 ]·2H 2 O (1), {[Cu(L1)(pydc)]·0.75H 2 O} n (2), and [Co 2 (L2) 2 (pydc) 2 ]·8H 2 O (3), [L1 = 1,2-bis(5,6-dimethylbenzimidazol-1-ylmethyl)benzene, H 2 pydc = 2,6-pyridinedicarboxylic acid, L2 = 1,4-bis(5-methylbenzimidazol-1-ylmethyl)benzene] were hydrothermally synthesized and characterized by IR spectra, elemental analysis, UV/Vis diffuse refraction spectroscopy, and X-ray single-crystal diffraction. Complexes 1 and 3 exhibit a dinuclear structure composed of two central cobalt atoms * Dr. G. H. Cui Fax: +86-0315-2592170 E-Mail: tscghua@126.com [a] College of Chemical EngineeringComplex 3 was synthesized by a similar procedure to that of 1, except that L1 ligand was replaced by L2 (38.0 mg, 0.1 mmol). The block-

A copper(II) complex with pyridine-2,6-dicarboxylic acid: Synthesis, characterization, thermal decomposition, bioactivity and interactions with herring sperm DNA

“…Pyridine dicarboxylic acids which contain a pyridine ring and two carboxylate groups can form various coordinated geometries [9][10][11], and their complexes have been used as electron carriers in some model biological systems as specific molecular tools in DNA cleavage and as NO scavengers [12]. Among the isomers (viz 2,3-, 2,4-, 2,5-, 2,6-, 3,4-and 3,5-H 2 pdc), pyridine-2,6-dicarboxylic acid (2,6-H 2 pdc) has attracted much interest in the synthesis of compounds, because two carboxyl groups with a 120° angle can provide widely varying coordination modes and form both discrete and consecutive metal complexes under the appropriate conditions [13]. 2,6-H 2 pdc is a versatile N and O donor ligand, and it can form stable chelates with numerous metal ions and exhibit diverse coordination geometries, such as bidentate, tridentate, meridian or bridging [14,15].…”

Effect of Flexible Bis(Benzimidazole) Ligands on the Structures of Cobalt(II) Coordination Polymers Derived from 2,6‐Naphthalenedicarboxylic Acid

“…All coordinated bonds are within normal distances. [25,26] The completely deprotonated nda 2-ligands adopt μ 2 -η 1 :η 1 -bidentate bridging through two carboxyl oxygen atoms con-necting the adjacent Co atoms along the bc direction to give rise to 1D zigzag chain with two kinds of Co1···Co1 separations of 13.3753(8) Å and 13.2148(8) Å and a Co1···Co1···Co1 angle of 100.759(3)° (Figure 1b). The difference observed in the Co1···Co1 separation by nda ligands can be attributed to slight adjustment in the coordination process between carboxylate groups and central Co atoms.…”

“…Overall, both complexes exhibited higher catalytic properties on the degradation of Congo red in a Fenton-like process than other reported complexes. [26,37,38] Since Co II species may play an important role in the reactions, hence, a further control experiment using equimolar CoCl 2 ·6H 2 O as used for the complexes were carried out under similar conditions. In the case, the degradation efficiency only reaches 55.5 %.…”

Pyridine-2,6-Dicarboxylic Acid Esters (pydicR2) as O,N,O-Pincer Ligands in CuII Complexes

“…Pyridine-2-6-dicarboxylate (pydic 2− ) is a frequently used ligand and coordinates are usually in a deprotonated tridentate mode. The coordinates use the N donor atom and the two carboxylate O donor functions, including the possibility of bridging (Scheme 1) [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. In contrast to this, the pydic ester ligands are neutral and have three options of tris-chelate O,N,O binding, which gives rise to three different isomers O carbonyl -M-O carbonyl (CC isomer), O carbonyl -M-O alkoxy (CA isomer), and O alkoxy -M-O alkoxy (AA isomer) (Scheme 1) while a bridging mode observed frequently for pydic 2− is less probable [15][16][17].…”