Reactivity of [1(2,3)4]pentamantane (Td-pentamantane): a nanoscale model of diamond.
To model the chemical properties of the hydrogen-terminated nanodiamond {111} and {110} surfaces, the functionalizations of the higher diamondoid [1(2,3)4]pentamantane were studied. [1(2,3)4]Pentamantane reacts selectively with neat bromine to give the medial 2-mono- and 2,4-disubstitution products. In contrast, oxidation with nitric acid as well as single-electron-transfer oxidation involving the [1(2,3)4]pentamantane radical cation results in apical C7-substitutions. This substitution pattern dominates in the free-radical bromination under phase-transfer catalytic conditions that gives a mixture of 7- and 2-bromo[1(2,3)4]pentamantane in a 95:5 ratio. Replacement of the functional groups in [1(2,3)4]pentamantane occurs without isomerization. This was demonstrated for the interconversions of the bromo and hydroxy derivatives as well as for the preparation of [1(2,3)4]pentamantyl-7-thiol from 7-hydroxy[1(2,3)4]pentamantane. Thus, the selective functionalization of hydrogen-terminated nanodiamonds is possible by means of reactions with common electrophiles-oxidizers.
Fokin
Andrey A
AA
Institut für Organische Chemie and Institut für Anorganische und Analytische Chemie, Justus-Liebig University, Heinrich-Buff-Ring 58, D-35392 Giessen, Germany.
Schreiner
Peter R
PR
Fokina
Natalie A
NA
Tkachenko
Boryslav A
BA
Hausmann
Heike
H
Serafin
Michael
M
Dahl
Jeremy E P
JE
Liu
Shenggao
S
Carlson
Robert M K
RM