Heterogeneous catalysts with programmable topologies generated by reticulation of organocatalysts into metal-organic frameworks:The case of squaramide

• 作者: Anna Broto-Ribas Claudia Vignatti Alicia Jimenez-Almarza Javier Luis-Barrera Zahra Dolatkhah Felipe Gándara Inhar Imaz Rubén Mas-Ballesté José Alemán Daniel Maspoch
• 来源期刊: 纳米研究（英文版）
• 年，卷（期）: 2021,（2）
• 所属期刊栏目: Research Articles
• 页码范围: 458-465
• 页数: 8页
• 语种: 英文

摘要

A well-established strategy to synthesize heterogeneous,metal-organic framework (MOF) catalysts that exhibit nanoconfinement effects,and specific pores with highly-localized catalytic sites,is to use organic linkers containing organocatalytic centers.Here,we report that by combining this linker approach with reticular chemistry,and exploiting three-dimensioanl (3D) MOF-structural data from the Cambridge Structural Database,we have designed four heterogeneous MOF-based catalysts for standard organic transformations.These programmable MOFs are isoreticular versions of pcu IRMOF-16,fcu UiO-68 and pillared-pcu SNU-8X,the three most common topologies of MOFs built from the organic linker p,p'-terphenyldicarboxylic acid (tpdc).To synthesize the four squaramide-based MOFs,we designed end synthesized a linker,4,4'-((3,4-dioxocyclobut-l-ene-1,2-diyl)bis(azanedyil))dibenzoic acid (Sq_tpdc),which is identical in directionality and length to tpdc but which contains organocatalytic squaramide centers.Squaramides were chosen because their immobilization into a framework enhances its reactivity and stability while avoiding any self-quenching phenomena.Therefore,the four MOFs share the same organocatalytic squaramide moiety,but confine it within distinct pore environments.We then evaluated these MOFs as heterogeneous H-bonding catalysts in organic transformations:a Friedel-Crafts alkylation and an epoxide ring-opening.Some of them exhibited good performance in both reactions but all showed distinct catalytic profiles that reflect their structural differences.