TY - JOUR
T1 - Iron-based metal-organic frameworks MIL-88B and NH2-MIL-88B
T2 - High quality microwave synthesis and solvent-induced lattice "breathing"
AU - Ma, Mingyan
AU - Bétard, Angélique
AU - Weber, Irene
AU - Al-Hokbany, Noura Saad
AU - Fischer, Roland A.
AU - Metzler-Nolte, Nils
PY - 2013/6/5
Y1 - 2013/6/5
N2 - Iron-based MIL-88B and NH2-MIL-88B microcrystals with high dispersibility and uniform size were successfully synthesized by using a rapid microwave-assisted solvothermal method. By carefully controlling the reaction conditions, the microwave method provided superior quality MIL-88B crystals in high yields and excellent phase purity. Framework flexibility was observed for both MIL-88B-Fe and NH2-MIL-88B-Fe frameworks in various solvents, which however significantly differs between the two materials. MIL-88B-Fe shrinks reversibly by about 25% only when it is dispersed in the strongly hydrogen bonding solvents water or methanol. In contrast, NH2-MIL- 88B-Fe shrinks up to 33% upon replacement of dimethylformamide (DMF) by any other solvent studied (benzene, chloroform, acetone, acetonitrile, methanol, water). The change in unit cell parameters (shortening of the a axis) can be seen macroscopically, although the overall integrity of the materials is maintained. We suggest that hydrogen bonding between the oxygen atoms of the MIL-88B-Fe framework and solvent molecules plays an important role in the framework shrinkage, while in the NH2-MIL-88B-Fe framework additional hydrogen bonds may form and thus a different breathing behavior is observed.
AB - Iron-based MIL-88B and NH2-MIL-88B microcrystals with high dispersibility and uniform size were successfully synthesized by using a rapid microwave-assisted solvothermal method. By carefully controlling the reaction conditions, the microwave method provided superior quality MIL-88B crystals in high yields and excellent phase purity. Framework flexibility was observed for both MIL-88B-Fe and NH2-MIL-88B-Fe frameworks in various solvents, which however significantly differs between the two materials. MIL-88B-Fe shrinks reversibly by about 25% only when it is dispersed in the strongly hydrogen bonding solvents water or methanol. In contrast, NH2-MIL- 88B-Fe shrinks up to 33% upon replacement of dimethylformamide (DMF) by any other solvent studied (benzene, chloroform, acetone, acetonitrile, methanol, water). The change in unit cell parameters (shortening of the a axis) can be seen macroscopically, although the overall integrity of the materials is maintained. We suggest that hydrogen bonding between the oxygen atoms of the MIL-88B-Fe framework and solvent molecules plays an important role in the framework shrinkage, while in the NH2-MIL-88B-Fe framework additional hydrogen bonds may form and thus a different breathing behavior is observed.
UR - http://www.scopus.com/inward/record.url?scp=84878665839&partnerID=8YFLogxK
U2 - 10.1021/cg301738p
DO - 10.1021/cg301738p
M3 - Article
AN - SCOPUS:84878665839
SN - 1528-7483
VL - 13
SP - 2286
EP - 2291
JO - Crystal Growth and Design
JF - Crystal Growth and Design
IS - 6
ER -