Synthetic routes, characterization and photophysical properties of luminescent, surface functionalized nanodiamonds

Abstract

The functionalization of small diameter (ca. 50 nm) polycarboxylated nanodiamond particles using amide coupling methodologies in both water and acetonitrile solvent has been investigated. In this manner, the surfaces of nanodiamond particles were adorned with different luminescent moities, including a green fluorescent 1,8-naphthalimide moiety (Nap-1), and a red emitting ruthenium(II) tris-bipyridine complex (Ru-1), as well as dual functionalisation with both luminophores. Comprehensive characterization of the surface functionalized nanodiamonds has been achieved using a combination of dynamic light scattering, nanoparticle tracking analysis, transmission electron microscopy, X-ray photoelectron spectroscopy, zeta potential measurements, microwave plasma atomic emission spectroscopy and time-resolved photophysics. The tendency of the functionalized nanodiamonds to aggregate reflects the degree of surface substitution, yielding small aggregates with typical particle sizes ca. 150 nm. This is likely to be driven by the reduction of the zeta potential, concomitant with the conversion of surface charged carboxylate groups to neutral amide functions. The results show that luminescent nanodiamond materials can be synthesised with tuneable photophysical properties. 1

High-Density Covalent Grafting of Spin-Active Molecular Moieties to Diamond Surfaces

“…Figure shows the ZP of nanodiamond samples after grafting with 10-undecenoic acid for different lengths of time, starting with air-annealed diamond samples that were then H-terminated as described above. Figure shows that H-terminated nanodiamond samples initially have a positive ZP, consistent with prior studies. , As the grafting reaction proceeds, the ZP becomes more negative due to the surface carboxylate groups, also in agreement with prior studies . Our data suggest that the initial grafting of reactant molecules is complete within approximately 30 min.…”

“…Figure 2 shows that H-terminated nanodiamond samples initially have a positive ZP, consistent with prior studies. 28,29 As the grafting reaction proceeds, the ZP becomes more negative due to the surface carboxylate groups, also in agreement with prior studies. 29 Our data suggest that the initial grafting of reactant molecules is complete within approximately 30 min.…”

Pickering emulsions stabilized by carboxylated nanodiamonds over a broad pH range

“…[70] Because of the low toxicity [24][25] and biocompatibility of ND, these emulsions hold promise in pharmaceutical and drug delivery applications. [29][30][31] We also envisage the manufacture of ND/polymer nanocomposites [21] by dissolving polymers in a volatile oil phase or by miniemulsion polymerization.…”

“…[28] Also, carboxylic functionalization of ND allows the covalent bonding or adsorption of a variety of moieties of interest in materials science and biomedicine, as well as superior drug and biomaterial loading capabilities. [29][30][31] 4…”

Porphyrin–Nanodiamond Hybrid Materials—Active, Stable and Reusable Cyclohexene Oxidation Catalysts

“…This allows surface functionalization, allowing the formation of electrostatic [4][5][6] or covalent linkages, and facilitating the preparation of hybrid organic-nanodiamond materials [7,8]. This has greatly contributed to a widespread application of these organic-nanodiamond carbon materials [9][10][11][12][13][14], in biomedicine [15][16][17][18], nonlinear optical materials [19,20], energy devices [21,22] and tribology [23,24].…”