Key indicators: single-crystal X-ray study; T = 200 K; mean (C-C) = 0.004 Å; Hatom completeness 97%; disorder in solvent or counterion; R factor = 0.040; wR factor = 0.103; data-to-parameter ratio = 12.7.The title compound, [Co 2 (C 9 H 4 N 2 O 4 ) 2 (H 2 O) 8 ]Á5H 2 O, contains two Co II ions that are bridged by two 1H-benzimidazole-5,6dicarboxylate ligands to form an M 2 L 2 type complex (M = metal and L = ligand). There are two crystallographically distinct M 2 L 2 units, each on an inversion centre, along with coordinated and uncoordinated water molecules, in the asymmetric unit. The Co II ions are octahedral. Extensive hydrogen bonding exists between the complex and water molecules, and this helps to stabilize the crystal structure. One water molecule is disordered over two sites with occupancies 0.84:0.16.
Related literatureMetal-organic coordination polymers using 1H-benzimidazole-5-carboxylic acid as a bridging ligand were reported by Guo et al. (2006) and Liu et al. (2005).
ExperimentalCrystal data [Co 2 (C 9 H 4 N 2 O 4 ) 2 (H 2 O) 8 ]Á5H 2 O M r = 760.35 Monoclinic, P2 1 =c a = 13.4210 (2) Å b = 9.1096 (2) Å c = 23.8185 (4) Å = 99.5191 (6) V = 2871.95 (9) Å 3 Z = 4 Mo K radiation = 1.25 mm À1 T = 200 (2) K 0.30 Â 0.18 Â 0.08 mm Data collection Nonius KappaCCD diffractometer Absorption correction: multi-scan (SADABS; Sheldrick, 2003) T min = 0.776, T max = 0.905 22168 measured reflections 5249 independent reflections 4216 reflections with I > 2(I) R int = 0.032
1-Bromo-2-phenylcyclopropene (2) underwent [2+2] dimerization to generate 1,2-dibromo-4,5-diphenyltricyclo[3.1.0.0(2,4)]hexane (5), which was heated to form 1,2-dibromo-4,5-diphenylcyclohexa-1,4-diene (6) followed by oxidation to yield 4',5'-dibromo-o-terphenyl (7). o-Terphenyl 7 could be synthesized in one-pot reactions from 1,1,2-tribromocyclopropane (3). When cyclopropane 3 was treated with 1.5 equiv of methyllithium followed by slowly adding the proton source, crossed [2+2] adduct 8 was isolated in 40% yield. Compound 8 was heated and oxidated to produce 4'-bromo-o-terphenyl (11).
After thiophene and furan were treated with n‐BuLi, respectively, the mixtures were reacted with various ketones and then dehydrated under acidic conditions. This reaction sequence led to the formation of 1‐(2‐heteroaryl)cycloalkenes and (2‐heteroaryl)alkenes. When the alkenes were treated with 10 mol % NIS, calix[4]arenes were produced as the major products, with minor amounts of calix[6]arenes sometimes being produced. Reducing the loading of NIS to 1 mol % and increasing its overall concentration to 6 M resulted in a substantial increase in the yield of hexaspirocyclohexyl calix[6]thiophene (from 2 to 66 %).
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