Patent number: 6376664
Abstract: Cyclic bis benzimidazole ligands of the following formula are formed by contacting a (2-aminophenyl)-benzimidazole-4-carboxaldehyde ethylene acetal or a (2-nitrophenyl)-benzimidazole-4-benzaldehyde with an acid optionally in the presence of a metal or a metal salt.
wherein
R1 and R2 may be the same or different and are selected from H, an alkyl having 1 to 10 carbon atoms, a benzyl group, a substituted 2-ethylphenyl group, a carbonyl group, a phenyl substituent, a tosyl group, and an alkylsulfonate group;
R3 and R4 may be the same or different and are selected from H, methyl, and ethyl; and
R5, R6, R7, R8, R9, R10, R11, R12, R13, R14, R15, R16, R17, and R18 may be the same or different and are selected from H, alkyl having 1 to 10 carbon atoms, fluoride, chloride, bromide, iodide, nitro, amino, a carboxylate, an ester, and a phenyl group.
Type:
Grant
Filed:
March 17, 2000
Date of Patent:
April 23, 2002
Assignee:
The Ohio State University
Inventors:
Michael K. Chan, Wai H. Kwok, Huichang Zhang, Maosheng Duan