Hengjiang Cong

Deciphering the Spatial Arrangement of Metals and Correlation to Reactivity in Multivariate Metal–Organic Frameworks

Thirty-six porphyrin-based metal-organic frameworks (MOFs) with composition of (M3O)2(TCPP-M)3 and M3O trigonal SBUs of various metals, Mg3O, Mn3O, Co3O, Ni3O, and Fe3O including mixed-metal SBUs, MnxFe3-xO, NixFe3-xO, CoxNi3-xO, MnxCo3-xO, MnxMg3-xO, and MnxNi3-xO were synthesized and characterized. These multivariate MOFs (MTV-MOFs) were examined by X-ray photoelectron spectroscopy, UV-vis diffuse reflectance spectra, and for the first time, their metal spatial arrangement deciphered and were found to exist in the form of either domains or well-mixed. We find that MTV-MOFs with well-mixed metals in their SBUs, rather than the SBUs having one kind of metal but different from one SBU to another, perform better than the sum of their parts in the test reaction involving the photo-oxidation of 1,5-dihydroxynaphthalene.

Principles of Designing Extra-Large Pore Openings and Cages in Zeolitic Imidazolate Frameworks

We report three design principles for obtaining extra-large pore openings and cages in the metal-organic analogues of inorganic zeolites, zeolitic imidazolate frameworks (ZIFs). Accordingly, we prepared a series of 15 ZIFs, members of which have the largest pore opening (22.5 Å) and the largest cage size (45.8 Å) known for all porous tetrahedral structures. The key parameter allowing us to access these exceptional ZIFs is what we define as the steric index (δ), which is related to the size and shape of the imidazolate linkers employed in the synthesis. The three principles are based on using multiple linkers with specific range and ratios of δ to control the size of rings and cages from small to large, and therefore are universally applicable to all existing ZIFs. The ZIF with the largest cage size (ZIF-412) shows the best selectivity of porous materials tested toward removal of octane and p-xylene from humid air.

Discovery of a 19F MRI sensitive salinomycin derivative with high cytotoxicity towards cancer cells

Salinomycin is a promising anti-cancer agent which selectively targets cancer stem cells. To improve its potency and selectivity, an analog library of salinomycin was generated by site-specific modification and CuAAc derivatization. Through a cytotoxicity analysis of the library, a fluorinated analog with high potency, selectivity, and (19)F MRI sensitivity was discovered as a novel theranostic agent.

Metal-organic frameworks for precise inclusion of single-stranded DNA and transfection in immune cells

Effective transfection of genetic molecules such as DNA usually relies on vectors that can reversibly uptake and release these molecules, and protect them from digestion by nuclease. Non-viral vectors meeting these requirements are rare due to the lack of specific interactions with DNA. Here, we design a series of four isoreticular metal-organic frameworks (Ni-IRMOF-74-II to -V) with progressively tuned pore size from 2.2 to 4.2 nm to precisely include single-stranded DNA (ssDNA, 11–53 nt), and to achieve reversible interaction between MOFs and ssDNA. The entire nucleic acid chain is completely confined inside the pores providing excellent protection, and the geometric distribution of the confined ssDNA is visualized by X-ray diffraction. Two MOFs in this series exhibit excellent transfection efficiency in mammalian immune cells, 92% in the primary mouse immune cells (CD4+ T cell) and 30% in human immune cells (THP-1 cell), unrivaled by the commercialized agents (Lipo and Neofect).Non-viral vectors are important for transfection but can be limited in the uptake, protection and release of ssDNA. Here, the authors report on the design of metal-organic-framework vectors with precisely controlled pore geometry and demonstrate the vector in the transfection of immune cells.

CCDC 1525655: Experimental Crystal Structure Determination

Related Article: Jingjing Yang, Yue-Biao Zhang, Qi Liu, Christopher A. Trickett, Enrique Gutierrez-Puebla, M. Angeles Monge, Hengjiang Cong, Abdulrahman Aldossary, Hexiang Deng, and Omar M. Yaghi|2017|J.Am.Chem.Soc.|139|6448|doi:10.1021/jacs.7b02272

CCDC 1423169: Experimental Crystal Structure Determination

Related Article: Jingjing Yang, Yue-Biao Zhang, Qi Liu, Christopher A. Trickett, Enrique Gutierrez-Puebla, M. Angeles Monge, Hengjiang Cong, Abdulrahman Aldossary, Hexiang Deng, and Omar M. Yaghi|2017|J.Am.Chem.Soc.|139|6448|doi:10.1021/jacs.7b02272

CCDC 1423175: Experimental Crystal Structure Determination

Related Article: Jingjing Yang, Yue-Biao Zhang, Qi Liu, Christopher A. Trickett, Enrique Gutierrez-Puebla, M. Angeles Monge, Hengjiang Cong, Abdulrahman Aldossary, Hexiang Deng, and Omar M. Yaghi|2017|J.Am.Chem.Soc.|139|6448|doi:10.1021/jacs.7b02272

CCDC 1423165: Experimental Crystal Structure Determination

Related Article: Jingjing Yang, Yue-Biao Zhang, Qi Liu, Christopher A. Trickett, Enrique Gutierrez-Puebla, M. Angeles Monge, Hengjiang Cong, Abdulrahman Aldossary, Hexiang Deng, and Omar M. Yaghi|2017|J.Am.Chem.Soc.|139|6448|doi:10.1021/jacs.7b02272