Anion-Exchange Properties and Reversible Phase Transitions of Metal-Cation-Mediated Bridged Organic-Inorganic Hybrid Mesoscopic Materials Xianzhu Xu, †,‡ Yu Han, † Lan Zhao, † Yi Yu, † Defeng Li, † Hong Ding, † Nan Li, † Ying Guo, † and Feng-Shou Xiao* ,† Department of Chemistry & State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University, Changchun 130023, China, and Department of Chemistry, Northeast Forestry University, Harbin 150040, China Received June 13, 2002. Revised Manuscript Received October 11, 2002 The anion-exchange properties of metal-cation-mediated bridged hybrid mesoscopic material (MBH) are carefully investigated. The results of chemical element analysis, XRD, FT-IR, and TG indicate that both small anions such as CH 3 COO - , NO 3 - , and large anion surfactant such as SDS - can be exchanged into MBH easily. All anion sites in MBH are exchangeable, which results in a remarkable anion-exchange capacity of 3.9 mmol g -1 . MBH shows reversible phase transitions among nearly hexagonal, lamellar, and amorphous structures when various anions are exchanged, which is assigned to the flexible nature of the alkyl chain in the framework of MBH. Introduction It is well-known that aluminosilicate zeolites are widely used as cation exchangers due to their anionic framework. 1,2 However, studies on materials, especially on inorganic materials, with anion-exchange capacity are rarely made. The most commonly used anion exchangers are anion-exchange resins, which is organi- cally based. Hydrotalcite clays 3 are one class of inorganic materials with anion-exchange properties. As for me- soporous materials, 4-10 which have a larger open frame- work than that of conventional zeolites, there are only a few reported examples 11-13 on anion-exchange proper- ties. Stein and co-workers prepared ordered alumino- phosphate and galloaluminophosphate mesoporous ma- terials with anion-exchange properties using polyoxo- metalate cluster as precursors. 11,12 Bhaumik and Ina- gaki synthesized mesoporous titanium phosphate with unusually high anion-exchange capacity. 13 So far, there is no silica-based mesoporous material with anion- exchange capacity reported in the literature to our knowledge. On the other hand, the development of hybrid mesoporous organosilicas 14-18 has greatly been made. Recently, Zhang and Dai reported the prepara- tion of ordered silica-based inorganic-organic hybrid mesoscopic materials, 17 which are metal-cation-medi- ated bridged and therefore designated MBH. MBH contains metal ions (Cd 2+ , Zn 2+ , and Ni 2+ ) as an integral part of their backbone, which have strong Coulombic interaction with anionic surfactant and are coordinated by functional ligands of 3-aminopropyltriethoxysilane (aptes, H 2 NCH 2 CH 2 CH 2 Si(OEt) 3 ). The siloxanes (aptes) connect with one another by condensation to form the whole framework. Thus, metal ions, organic functional groups, and silica are uniformly distributed in the framework of MBH. In this investigation, we find a remarkable anion- exchange capacity of MBH, which results from the * To whom correspondence should be addressed. Phone: +86-431- 8922331-2314. Fax: +86-431-5671974. E-mail: fsxiao@mail.jlu.edu.cn. † Jilin University. ‡ Northeast Forestry University. (1) Szostak, R. Molecular Sieves: Principles of Synthesis and Identification; Van Nostrand Reinhold: New York, 1989. (2) Corma, A. Chem. Rev. 1997, 97, 2373. (3) Matsushita, T.; Ebitani, K.; Kaneda, K. Chem. Commun. 1999, 265. (4) (a) Kresge, C. T.; Leonowicz, M. E.; Roth, W. J.; Vartuli, J. C.; Beck, J. S. Nature 1992, 352, 710. (b) Beck, J. S.; Vartuli, J. C.; Roth, W. J.; Leonowicz, M. E.; Kresge, C. T.; Schmitt, K. D.; Chu, C. T-W.; Olson, D. H.; Sheppard, E. W.; McCullen, S. B.; Higgins, J. B.; Schlenker, J. L. J. Am. Chem. Soc. 1992, 114, 10834. (5) (a) Huo, Q.; Margolese, D. I.; Stucky, G. D. Chem. Mater. 1996, 8, 1147. (b) Zhao, D.; Feng, J.; Huo, Q.; Melosh, N.; Fredrickson, G. H.; Chmelka, B. F.; Stucky, G. D. Science 1998, 279, 548. (c) Zhao, D.; Huo, Q.; Feng, J.; Chmelka, B. F.; Stucky, G. D. J. Am. Chem. Soc. 1998, 120, 6024. (6) Tanev, P. T.; Pinnavaia, T. J. Science 1995, 267, 865. (7) (a) Ryoo, R.; Kim, J. M.; Shin, C. H. J. Phys. Chem. 1996, 100, 17718. (b) Ryoo, R.; Joo, S. H.; Kruk, M.; Jaroniec, M. Adv. Mater. 2001, 13, 677. (c) Joo, S. H.; Choi, S. J.; Oh, I.; Kwak, J.; Liu, Z.; Terasaki, O.; Ryoo, R. Nature 2001, 412, 169. (8) (a) Ying, J. Y.; Mehnert, C. P.; Wong, M. S. Angew. Chem., Int. Ed. 1999, 38, 56. (b) Wong, M. S.; Jeng, E. S.; Ying, J. Y. Nano Lett. 2001, 1, 637. (9) (a) Liu, Y.; Zhang, W.; Pinnavaia, T. J. J. Am. Chem. Soc. 2000, 122, 8791. (b) Liu, Y.; Zhang, W.; Pinnavaia, T. J. Angew. Chem., Int. Ed. 2001, 40, 1255. (10) Zhang, Z.; Han, Y.; Zhu, L.; Wang, R.; Yu, Y.; Qiu, S.; Zhao, D.; Xiao, F.-S. Angew. Chem., Int. Ed. 2001, 40, 1258. (11) Holland, B. T.; Isbester, P. K.; Blanford, C. F.; Munson, E. J.; Stein, A. J. Am. Chem. Soc. 1997, 119, 6796. (12) Kron, D. A.; Holland, B. T.; Wipson, R.; Maleke, C.; Stein, A. Langmuir 1999, 15, 8300. (13) Bhaumik, A.; Inagaki, S. J. Am. Chem. Soc. 2001, 123, 691. (14) Inagaki, S.; Guan, S.; Fukusgima, Y.; Ohsuma, T.; Terasaki, O. J. Am. Chem. Soc. 1999, 121, 9611. (15) Melde, B. J.; Holland, B. T.; Blanford, C. F.; Stein, A. Chem. Mater. 1999, 11, 3302. (16) Asefa, T.; Maclachlan, M. J.; Coombs, N.; Ozin, G. A. Nature 1999, 402, 867. (17) Zhang, Z.; Dai, S. J. Am. Chem. Soc. 2001, 123, 9204. (18) Inagaki, S.; Guan, S.; Ohsuna, T.; Terasaki, O. Nature 2002, 416, 304. 74 Chem. Mater. 2003, 15, 74-77 10.1021/cm020666n CCC: $25.00 © 2003 American Chemical Society Published on Web 11/09/2002