Surfactant Media To Grow New Crystalline Cobalt 1,3,5-Benzenetricarboxylate Metal–Organic Frameworks

In this report, three new metal–organic
frameworks (MOFs), [Co3(μ3-OH)­(HBTC)­(BTC)2Co­(HBTC)]·(HTEA)3·H2O (NTU-Z30), [Co­(BTC)]·HTEA·H2O (NTU-Z31), [Co3(BTC)4]·(HTEA)4 (NTU-Z32), where H3BTC = 1,3,5-benzenetricarboxylic
acid, TEA = triethylamine, and NTU = Nanyang Technological University,
have been successfully synthesized under surfactant media and have
been carefully characterized by single-crystal X-ray diffraction,
powder X-ray diffraction, thermogravimetric analysis, and IR spectromtry. NTU-Z30 has an unusual trimeric [Co3(μ3-OH)­(COO)7] secondary building unit (SBU), which
is different from the well-known trimeric [Co3O­(COO)6] SBU. The topology studies indicate that NTU-Z30 and NTU-Z32 possess two new topologies, 3,3,6,7-c net
and 2,8-c net, respectively, while NTU-Z31 has a known
topology rtl type (3,6-c net). Magnetic analyses show
that all three materials have weak antiferromagnetic behavior. Furthermore, NTU-Z30 has been selected as the heterogeneous catalyst for
the aerobic epoxidation of alkene, and our results show that this
material exhibits excellent catalytic activity as well as good stability.
Our success in growing new crystalline cobalt 1,3,5-benzenetricarboxylate
MOFs under surfactant media could pave a new road to preparing new
diverse crystalline inorganic materials through a surfactant-thermal
method.