Synthesis and characterization of functionalized third generation molecular motors

Light-driven molecular motors exhibit the capability to perform work when exposed to light irradiation. To harness work, it is necessary to overcome their random motion. A solution concerns their immobilization onto a surface. This thesis project originates from this challenge. The primary objective of this project is to synthesize and characterize third-generation molecular motors incorporating substituent groups on their rotor. These substituents are intended to be used to enable the immobilization of the motors onto a solid surface. Third-generation motors featuring functional groups on their rotors represent an unexplored challenge. The synthesis of these motors was conducted following the Barton-Kellogg procedure, which employs a diazo compound and a thioketone reagent, resulting in the formation of sterically hindered alkenes. As a starting point, attempts were made to synthesize motors with two different substituents on the rotors, the methoxy and bromine groups, positioned in two distinct locations. Several attempts were made to obtain these compounds, as the literature-reported procedure did not yield any valid results. Through the adaptation of synthetic procedures and the variation of reaction parameters, two different molecular motors were successfully synthesized: 9,9’-(2-fluoro-2,4,7-trimethyl-1H-indene-1,3(2H)-diylidene)bis(2,7-dibromo-9H-fluorene) and 9,9’-(2-fluoro-2,4,7-trimethyl-1H-indene-1,3(2H)-diylidene)bis(3,6-dibromo-9H-fluorene). Both motors featured bromine as the substituent, but in two different positions. Unfortunately, the motor with the methoxy groups could not be successfully synthesized, despite numerous optimization attempts. Once the aforementioned motors were obtained, they underwent detailed characterization using various spectroscopic techniques. NMR analyses provided insights into the molecular structure of the compounds.