Repository Data for Magic Diamond: Covalent Bond Formation of Melamine and other Amines on Nanodiamond Surfaces

Includes the data for X-ray absorption spectroscopy, resonant inelastic X-ray scattering maps, X-ray photoelectron spectroscopy and FTIR spectroscopy. The uploaded data is for the manuscript entitled Magic Diamond: Covalent Bond Formation of Melamine and other Amines on Nanodiamond Surfaces. ACS Omega and the American Chemical Society highly encourage open source sharing of data.

Abstract:
High-temperature high-pressure (HPHT) nanodiamond (ND) hosts nitrogen-vacancy (NV) centers, solid-state qubits that enable room-temperature quantum sensing by all-optical magnetometry, electrometry, and thermometry. However, covalent surface functionalization of nanoscale diamond remains largely limited to carboxylate-based chemistries. Amine termination is particularly attractive because theoretical studies predict suppression of mid-gap states and extended electron-spin coherence times. Recently, chemical activation of alcohol-terminated NDs to alkyl bromides (ND-Br) using SOBr₂ has enabled nucleophilic substitution through a carbocation intermediate, allowing formation of simple amine terminations. Here, we evaluate whether sterically demanding amines can form covalent diamond–nitrogen bonds on ND-Br surfaces. ND-Br was reacted with branched, linear, and cyclic amines, including polyethyleneimine, diethylenetriamine, and melamine. X-ray spectroscopies were used to confirm successful amination and to probe the resulting electronic structure at the diamond–amine interface. These results expand the chemical toolbox for tuning diamond surface dipoles and electron affinity, providing new pathways for engineering nanodiamond surfaces for quantum sensing and photocatalysis applications.