The development of metal-organic frameworks using palladium metal complexes for catalysis and the utilization of a dihaloimidazolidinedione for easy acid chloride generation

Part 1. Metal-Organic Frameworks (MOFs) have been extensively studied due to their functional versatility and well-defined, porous structures. It is, however, exceptionally rare to find MOFs that use late transition metal complexes as a building block. Incorporation of these complexes would have immediate applications in catalysis and enhanced gas adsorption/storage. Furthermore, because of the MOF’s well-defined structures, heterogeneous catalysis properties can be more readily studied and improved. Herein, 1,2-bis(bi(para-carboxyl)phenylphosphino)benzene palladium dichlo-ride’s (PdCl2(BBCB)) catalytic ability is studied using the Mizoroki-Heck reaction, and 1,2-bis(bi(4-carboxy-biphenyl-4’-phosphino))ethane palladium dichloride (PdCl2(BBCE-1L)) is used to make a MOF with an enlarged pore size and greater catalytic ability. BBCB, a tetra-para-carboxylic acid derivative of dppb, is used to form a palladium dichloride bis(phosphine) complex. This complex was found to perform a Mizoroki-Heck reaction in decent yields despite formation of palladium black. BBCE-1L, a tetra-4-carboxylic acid biphenyl derivative of dppe, was then developed to deter palladium black formation and enlarge the pore size of the MOF. A MOF was made using a Zn(II) paddlewheel as the metal node and PdCl2(BBCE-1L) as the organic linker. This MOF was found to have moderate thermal stability and potentially high pore volume. Part 2. Acid chloride generation is a widely researched field for the synthesis of amides and esters, motifs found throughout nature and pharmaceuticals. Recently, we found that dihaloimidazolidinediones could substitute a variety of alcohols with halogens through an amide-stabilized carbocation. As an extension of this chemistry, we were able to activate most carboxylic acids into the corresponding acid chloride with near quantitative yields. Mechanistic studies of electronic and steric effects suggest that the rate-determining step is the nucleophilic attack of a free chloride ion on the carbonyl center to produce the corresponding acid chloride. Electronic effects of ring size on electrophilicity was also observed and explained through analysis of a simplified Walsh diagram.