Phosphonated and epoxy-containing norbornene based monomers were prepared by Diels–Alder reaction. They were then combined with three other commercial cyclic unsaturated monomers to synthesize phosphonated homopolymers and copolymers via ring opening metathesis polymerization (ROMP) using second-generation Grubbs catalyst. Glass transitions of these polymers were tunable in a broad range from −14 to 91 °C by varying the flexibility of comonomer. Interestingly, copolymerization with cyclopentene inhibited the crystallization of polycyclopentene, and instead, led to a copolymer with two T_gs. Paradoxically, results from thermogravimetric analysis (TGA) were not consistent with the followed flame-retarding experiment, implying that the early weight loss from phosphonated moieties did not deleteriously affect the flame-resistant property which actually depended more on the percentage of char residual after thermal degradation. In application studies, the norbornene derivative phosphonated polymer was tested for the first time as flame retarding material, and showed significant self-extinguishing ability. In a second study, photolithography was also successfully performed via thiol-ene “click” chemistry, which allowed the phosphonated polymer a promising negative photoresist. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 1396-1408

Boryl radicals have the potential for the development of new molecular entities and for application in new radical reactions. However, the effects of the substituents and coordinating Lewis bases on the reactivity of boryl radicals are not fully understood. By using first-principles methods, we investigated the spin-density distribution and reactivity of a series of boryl radicals with various substituents and Lewis bases. The substituents, along with the Lewis bases, only affect the radical reactivity when an unpaired electron is in the boron p_z orbital, that is, for three-coordinate radicals. We found evidence of synergistic effects between the substituents and the Lewis bases that can substantially broaden the tunability of the reactivity of the boryl radicals. Among Lewis bases, pyridine and imidazol-2-ylidene show a similar capacity for stabilization by delocalizing the spin density. Electron-donating substituents, such as nitrogen, more efficiently stabilize boryl radicals than oxygen and carbon atoms. The reactivity of a boryl radical is always boron based, irrespective of the spin density on boron.

Di- and polyboron (hetero)arenes, site-differentiated with MIDA boronyl (MIDA=N-methyliminodiacetic acid) and pinacolato boronyl (Bpin), were prepared by an iridium-catalyzed direct CH borylation of readily available (hetero)aryl MIDA boronates. The excellent synthetic uses of these multisite nucleophiles were demonstrated by the high-yield production of a variety of multifunctionalized poly(hetero)arenes with the highly chemoselective Suzuki–Miyaura coupling (SMC) of the Bpin moiety being an essential step.

Di- and polyboron (hetero)arenes, site-differentiated with MIDA boronyl (MIDA=N-methyliminodiacetic acid) and pinacolato boronyl (Bpin), were prepared by an iridium-catalyzed direct CH borylation of readily available (hetero)aryl MIDA boronates. The excellent synthetic uses of these multisite nucleophiles were demonstrated by the high-yield production of a variety of multifunctionalized poly(hetero)arenes with the highly chemoselective Suzuki–Miyaura coupling (SMC) of the Bpin moiety being an essential step.