title: Why do the [PhSiO(1.5)](8,10,12) cages self-brominate primarily in the ortho position? Modeling reveals a strong cage influence on the mechanism.
abstract: (PhSiO1.5)8,10,12 cages are bulky, electron withdrawing like CF3; yet self-brominate (60 °C), favoring ortho substitution: PhT8 (≈85%), PhT10 (≈75%) and PhT12 (60%). First-principles calculations suggest bromination initiates when Br2 is "trapped" via H-bonding to ortho-H's, followed by polarization via strong interactions with cage faces, possibly cage LUMOs.
authors.affiliation: Dept. of Mater. Sci. & Eng, Univ. of Michigan, Ann Arbor, MI 48109, USA. talsdad@umich.edu.
authors.forename: M
authors.initials: M
authors.lastname: Bahrami
authors.forename: H
authors.initials: H
authors.lastname: Hashemi
authors.forename: X
authors.initials: X
authors.lastname: Ma
authors.forename: J
authors.initials: J
authors.lastname: Kieffer
authors.forename: R M
authors.initials: RM
authors.lastname: Laine