Structural Modularity of Unique Multicomponent Hydrogen-Bonded Organic Frameworks Based on Organosilanetriols and Silanediols as Molecular Building Blocks

• Published in: Crystal growth & design 2018-07, Vol.18 (7), p.3805-3819
• Main Authors: de J. Velásquez-Hernández, Miriam, Torres-Huerta, Aaron, Martínez-Otero, Diego, Sánchez-González, Elí, Hernández-Balderas, Uvaldo, Ibarra, Ilich A, Jancik, Vojtech
• Format: Article
• Language: English
• ISSN: 1528-7483; 1528-7505
• DOI: 10.1021/acs.cgd.8b00030

In this study we examined the use of a new class of molecular building blocks with tetrahedral nodes based on organo-bis­(silanetriols) (1,4-[(HO)3­SiOCEt2]2­C6H4 (1) and 4,4′-[(HO)3­SiOCEt2]2-(1,1′-biphenyl) (2)) and organo-bis­(silanediol) (1,4-[{(HO)2­( t BuO)­Si}­OCEt2]2­C6H4 (3)) for the synthesis of multicomponent hydrogen-bonded organic frameworks (HOFs) with adjustable supramolecular patterns, and modular assembly. Thus, such reticular arrangements were readily obtained by the cocrystallization of bridged organosilanols (1, 2, and 3) with an organic diamine (1,4-diazabicyclo[2.2.2]­octane (a) or trans-1,2-bis­(4-pyridyl)­ethylene (b)) to yield the corresponding HOFs 1a, 1b, 2a, 2b, 3a, and 3b. Single-crystal X-ray diffraction analysis revealed that the dimensionality of the network, and by consequence, its porosity, can be easily engineered by means of the modulation of the central organic backbone of the organosilanol-based tectons, as well as by the Lewis basicity and the size of the corresponding organic diamine. In this context, it was found that although 1a presents a nonporous arrangement, changing either the organic diamine as in 1b, or the spacer’s size as in 2a, it is possible to generate one-dimensional channels or zero-dimensional voids, respectively. Moreover, through gas sorption experiments, it was demonstrated that 1b exhibits structural flexibility and permanent porosity with selective adsorption of CO2 over N2.