Metal–Organic Conjugated Microporous Polymers

Abstract

Microporous materials have potential applications in areas including molecular separation, gas sorption and catalysis. [1] Materials such as metal-organic frameworks (MOFs), [2] covalent organic frameworks (COFs), [3] microporous organic polymers, [4] and porous organic molecular solids [5] all contain organic functionalities which, in principle, can allow significant synthetic diversification. A particular advantage of microporous organic polymers [4] is the potential to introduce a range of useful chemical functionalities into the pores. [6] This stems from the chemical and thermal stability of these networks which facilitates a variety of chemical transformations.Conjugated microporous polymers (CMPs) [4a] can exhibit extended p-conjugation and have been the subject of much recent interest. A variety of CMPs (and closely related structures) have been developed. [4a, 7] The incorporation of metal sites into CMPs could open up second-generation porous materials with useful combined chemical and physical properties such as catalytic activity, electrical conductivity, or light-absorption/emission.[8] For example, metalated CMP materials might be of interest in heterogeneous catalysis or photocatalysis, where high surface areas would be beneficial. There are, however, few demonstrations of the functionalization of CMP networks with metals at the molecular level. The incorporation of metal nanoparticles into microporous networks has been demonstrated.[4e, 7e, 9a] Also, a lithiated CMP showing very high H 2 sorption was described recently but the precise nature of the metal incorporation at the molecular level was not clear.[9b] Another recent report details a porphyrin-derived microporous organic polymer which shows high catalytic activity for the oxidation of thiols. [10] Beyond this, there are no reports on the purposeful synthesis of metal-functionalized CMPs. Here, we report two versatile strategies for preparing metal-organic CMPs (MO-CMPs). Unlike MOFs, [2] the resulting metal-containing conjugated polymers are amorphous. Another significant difference is that the metal sites need not be nodes in the network but can also be attached pendant to the polymer chains, thus allowing the introduction of vacant metal sites and a range of chemically active functionalities. The introduction of pendant metal sites rather than metal nodes also allows the preparation of materials with unbroken extended conjugation.The MO-CMP networks were prepared either by posttreating a bipyridine-functionalized CMP precursor with a metal complex or by the direct Sonogashira-Hagihara crosscoupling of 1,3,5-triethylbenzene or 1,4-dibromobenzene and a halogenated metal-organic co-monomer. These two strategies can be defined as post-synthetic metalation and direct metal incorporation by copolymerization. The representative structures of the target MO-CMP networks are shown in Scheme 1. These polymers combine conjugation along the main chain with functional units such as bipyridine or phenylpyridine in the backbone in order to provide site...

A review: methane capture by nanoporous carbon materials for automobiles

“…Furthermore, conjugated microporous polymers (CMPs) have been of interest because of their porous structures with organic functionalities, for such applications as gas storage, capture, and separation [61][62][63][64]. In particular, the committee of CMPs offers novel materials capable of CH 4 storage and their properties can be reduced effectively.…”

Conjugated Microporous Polymers for Heterogeneous Catalysis

“…[13] By comparison, the metal node in CMP-1 does not break the conjugation in the network, although it does in MOFs. [14] CMP-1 as ah eterogeneous catalyst showed high catalytic activity for reductive amination for aw ide range of substrates ( Figure 1).…”

“…Asian J. 2018,13,[9][10][11][12][13][14][15][16][17][18][19] www.chemasianj.org 2018 Wiley-VCH Verlag GmbH &Co. KGaA, Weinheim activity waso bservedw ith Ru/CMP-5d after three cycles,t he ee value decreased from 94 %t o9 0% (reaction time:2 4h). Additionally, CMP-5d supported Ir species displayedh ighera ctivity for asymmetrich ydrogenationo fq uinaldine than the homogeneousI r/BINAP system.…”

“…Asian J. 2018,13,[9][10][11][12][13][14][15][16][17][18][19] www.chemasianj.org Figure 10. Structureso fCMPs used as photocatalysts.…”

Imine-linked conjugated organic polymer bearing bis(imino)pyridine ligands and its catalytic application in C–C coupling reactions

“…The successful design and synthesis of these polymers linked by B-O [3][4][5], C-C [6,7], C-N [8], and C=N [9][10][11][12] bonds have been reported. Recent studies have shown that conjugated organic polymers (COPs) with extended π-conjugation possess high thermal stability and structure diversity [13][14][15]. However, the synthesis of these COP materials usually requires expensive precursors and intricate techniques.…”