Boron compounds containing polymer group and their applications

Boron compounds with Lewis acidic boron centers attract the attention of the academic community day by day due to their wide application areas. Due to its unique properties and different chemical structures, it has tremendous influence in the development of new chemical compounds and broadened the scope of the skeleton of accessible complex molecules. Recent studies clearly show that boron compounds containing polymeric groups can be perfectly synthesized through controlled/live polymerization, ring-opening polymerization (ROP) and other polymerization techniques. Here, boron compounds containing polymer group, which is an important member of the boron class, have been reviewed. First, tri-coordinated boron-based biodegradable poly(ε-caprolactone) (PCL) and poly(L-lactide) (PLLA) polymers with well-defined structures and their tetra-coordinated forms containing B←N coordination bonds were synthesized. The newly synthesized boronate ester and polymers were characterized by elemental analysis, NMR (1H, 13C, and 11B) spectroscopy, FT-IR spectroscopy, UV-Vis spectroscopy, fluorescence spectroscopy, and LC-MS/MS spectrometry. The thermal and morphological behavior of the boron polymers were studied by TG-DTA, DTG, and SEM techniques. Secondly, boron-containing salen ligands and their tetra-coordinated boron-based polymers containing N→B coordination bonds were synthesized under suitable conditions. Structures of synthesized boron-containing salen ligands and tetra-coordinated polymers containing corresponding N→B coordination bonds, melting point, elemental analysis, LC-MS/MS spectrometry, FT-IR spectroscopy, UV-Vis spectroscopy and NMR (1H, 13C and 11B NMR) spectroscopy was illuminated. The use of synthesized boron-containing salen ligands and their polymers containing N→B coordination bonds as novel organocatalysts in the transfer hydrogenation of various aromatic ketones under suitable conditions were tested. Considering all the catalytic results, salen ligands and tetra-coordinated boron-based polymers containing their N→B coordination bonds appear to be suitable organocatalysts for future transfer hydrogenation. And thirdly, boronic acid and boronate ester-based polymers containing polymer groups were synthesized. Structures of synthesized boronic acid and boronate ester-based polymers were characterized by NMR (1H, 13C, and 11B) spectroscopy, FT-IR spectroscopy, UV-Vis spectroscopy, fluorescence spectroscopy, and LC-MS/MS spectrometry.