Afaq Sheereen, Akram Muhammad Usman, Malik Wasif Mahmood Ahmed, Ismail Muhammad, Ghafoor Abdul, Ibrahim Muhammad, Nisa Mehr Un, Ashiq Muhammad Naeem, Verpoort Francis, Chughtai Adeel Hussain
Institute of Chemical Sciences, Bahauddin Zakariya University, Multan 60800, Pakistan.
Department of Chemistry, Emerson University Multan, Multan 60000, Pakistan.
ACS Omega. 2023 Feb 10;8(7):6638-6649. doi: 10.1021/acsomega.2c07137. eCollection 2023 Feb 21.
Acyl-amide is extensively used as functional group and is a superior contender for the design of MOFs with the guest accessible functional organic sites. A novel acyl-amide-containing tetracarboxylate ligand, bis(3,5-dicarboxy-pheny1)terephthalamide, has been successfully synthesized. The HL linker has some fascinating attributes as follows: (i) four carboxylate moieties as the coordination sites confirm affluent coordination approaches to figure a diversity of structure; (ii) two acyl-amide groups as the guest interaction sites can engender guest molecules integrated into the MOF networks through H-bonding interfaces and have a possibility to act as functional organic sites for the condensation reaction. A mesoporous MOF ([Cu(L)(HO)]·4DMF·6HO) has been prepared in order to produce the amide FOS within the MOF, which will work as guest accessible sites. The prepared MOF was characterized by CHN analysis, PXRD, FTIR spectroscopy, and SEM analysis. The MOF showed superior catalytic activity for Knoevenagel condensation. The catalytic system endures a broad variety of the functional groups and presents high to modest yields of aldehydes containing electron withdrawing groups (4-chloro, 4-fluoro, 4-nitro), offering a yield > 98 in less reaction time as compared to aldehydes with electron donationg groups (4-methyl). The amide decorated MOF (LOCOM-1-) as a heterogeneous catalyst can be simply recovered by centrifugation and recycled again without a flagrant loss of its catalytic efficiency.
酰基酰胺作为官能团被广泛使用，是设计具有客体可及官能有机位点的金属有机框架（MOF）的优秀候选物。一种新型的含酰基酰胺的四羧酸配体，双（3,5 - 二羧基苯基）对苯二甲酰胺，已成功合成。配体HL具有以下一些引人关注的特性：（i）四个羧基部分作为配位位点确保了丰富的配位方式以形成多样的结构；（ii）两个酰基酰胺基团作为客体相互作用位点能够使客体分子通过氢键界面整合到MOF网络中，并有可能作为缩合反应的官能有机位点。为了在MOF内部产生酰胺官能有机位点（FOS），制备了一种介孔MOF（[Cu(L)(H₂O)]·4DMF·6H₂O），该位点将作为客体可及位点。通过CHN分析、粉末X射线衍射（PXRD）、傅里叶变换红外光谱（FTIR）和扫描电子显微镜（SEM）分析对所制备的MOF进行了表征。该MOF对Knoevenagel缩合反应表现出优异的催化活性。该催化体系能耐受多种官能团，对于含有吸电子基团（4 - 氯、4 - 氟、4 - 硝基）的醛类，产率较高至中等，与含有供电子基团（4 - 甲基）的醛相比，在更短的反应时间内产率>98%。作为非均相催化剂的酰胺修饰的MOF（LOCOM - 1 - ）可以通过离心简单回收并再次循环使用，而其催化效率不会明显损失。
