posted on 2022-01-27, 13:39authored byCynthia Melendrez, Jorge A. Lopez-Rosas, Camron X. Stokes, Tsz Ching Cheung, Sang-Jun Lee, Charles James Titus, Jocelyn Valenzuela, Grace Jeanpierre, Halim Muhammad, Polo Tran, Perla Jasmine Sandoval, Tyanna Supreme, Virginia Altoe, Jan Vavra, Helena Raabova, Vaclav Vanek, Sami Sainio, William B. Doriese, Galen C. O’Neil, Daniel S. Swetz, Joel N. Ullom, Kent Irwin, Dennis Nordlund, Petr Cigler, Abraham Wolcott
Bromination of high-pressure, high-temperature
(HPHT) nanodiamond
(ND) surfaces has not been explored and can open new avenues for increased
chemical reactivity and diamond lattice covalent bond formation. The
large bond dissociation energy of the diamond lattice–oxygen
bond is a challenge that prevents new bonds from forming, and most
researchers simply use oxygen-terminated NDs (alcohols and acids)
as reactive species. In this work, we transformed a tertiary-alcohol-rich
ND surface to an amine surface with ∼50% surface coverage and
was limited by the initial rate of bromination. We observed that alkyl
bromide moieties are highly labile on HPHT NDs and are metastable
as previously found using density functional theory. The strong leaving
group properties of the alkyl bromide intermediate were found to form
diamond–nitrogen bonds at room temperature and without catalysts.
This robust pathway to activate a chemically inert ND surface broadens
the modalities for surface termination, and the unique surface properties
of brominated and aminated NDs are impactful to researchers for chemically
tuning diamond for quantum sensing or biolabeling applications.