Synthesis of Periodic Large Mesoporous Organosilicas and Functionalization by Incorporation of Ligands into the Framework Wall Haoguo Zhu, Deborah J. Jones,* Jerzy Zajac, Roger Dutartre, Mohammed Rhomari, and Jacques Rozie `re Laboratoire des Agre ´ gats Mole ´ culaires et Mate ´ riaux Inorganiques, UMR CNRS 5072, Universite ´ Montpellier II, Place Euge ` ne Bataillon, 34095 Montpellier Cedex 5, France Received December 27, 2001. Revised Manuscript Received June 11, 2002 Highly ordered large mesopore organosilicas have been obtained by direct liquid crystal templating in acid media using bridged silsesquioxane (EtO) 3 Si-CH 2 -CH 2 -Si(OEt) 3 [bis- (triethoxysilyl)ethane, BTSE] precursor and triblock copolymers as structure-directing species. The degree of long-range ordering of the structure as determined from X-ray diffraction and transmission electron microscopy, and the most probable pore diameter, in the range 4-8 nm, were observed to depend on the concentration of triblock copolymer used in the synthesis. Further pore-wall functionalization was achieved by co-condensation with Cu(II)-complexed N,N′-bis[3-(trimethoxysilyl)propyl]ethylenediamine (BTSPED). Surfactant extraction produces periodic mesoporous organosilicas functionalized with this complex in the framework, from which the Cu(II) can then be removed by acid leaching. Such hybrid bridged bifunctional organosilicas are homogeneously mesoporous, and the pore diameter increases in the range 11-21 nm as the mole ratio of BTSPED to BTSE is increased from 0.1 to 0.3. 29 Si MAS NMR shows that under the conditions used, no cleavage of the Si-C bond occurs, and suggests that the degree of condensation is higher in the bridged bifunctional organosilicas than in the bridged monofunctional organosilicas. Introduction The properties of ordered mesoporous materials and hybrid organic-inorganic frameworks have recently been combined in a novel class of materials possessing organic fragments as wall components of a mesoporous framework. 1-3 These materials, denoted unified organi- cally functionalized mesoporous networks (UOFMN) 2 or periodic mesoporous organosilicas (PMOs), 3 are pre- pared through the surfactant-templated condensation of bifunctional organosiloxane presursors (R′O) 3 SiRSi- (OR′) 3 with R )-CH 2 -, -CH 2 -CH 2 -, -CH 2 d CH 2 -, etc. 1-9 The elaboration of PMOs represents an exciting new development, as the choice of the organic groups incorporated, and the synthesis conditions employed, create a broad opportunity for fine-tuning of porous structure, surface and framework characteristics, reac- tivity and functionality, for example in catalysis, sepa- rations, and advanced materials design. Since the first three papers devoted to PMOs were published in 1999, 1-3 periodic mesoporous organosilicas have, to the best of our knowledge, been synthesized in solutions of low surfactant concentration, with surfactant liquid crystal phases and mesoporous organosilicas being formed in a cooperative manner driven by charge density matching between surfactant assemblies and inorganic precursors; and in all cases the pore diameters of well-ordered materials are limited to less than 4 nm. However, PMOs with larger pores are desirable for a variety of possible applications such as hosts for chemi- cal reactions, uses in separations, immobilization or encapsulation involving large molecules, etc. 10-12 Gen- erally speaking, the family of nonionic block copolymers can template the synthesis of large mesoporous silica in strong acid (2 M HCl). 13 In bridged silsesquioxane systems, however, the charge density on organosilicate species formed by hydrolysis and oligomerization of organosiloxanes under acid or base conditions is lower than that on a silicate species formed from monosilane * To whom correspondence should be addressed. E-mail: debtoja@ univ-montp2.fr. (1) Inagaki, S.; Guan, S.; Fukushima, Y.; Ohsuna, T.; Terasaki, O. J. Am. Chem. Soc. 1999, 121, 9611. (2) Melde, B. J.; Hollande, B. T.; Blanford, C. F.; Stein, A. Chem. Mater. 1999, 11, 3302. (3) Asefa, T.; MacLachlan, M. J.; Coombs, N.; Ozin, G. A. Nature 1999, 402, 867. (4) MacLachlan, M. J.; Asefa, T.; Ozin, G. 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Soc. 1998, 120, 6024. 4886 Chem. Mater. 2002, 14, 4886-4894 10.1021/cm011742+ CCC: $22.00 © 2002 American Chemical Society Published on Web 11/01/2002