Robust gold−carbon nanoparticles were synthesized by the sodium borohydride reduction of the diazonium tetrachloroaurate(III) complex [C 8 F 17 -4-C 6 H 4 NN]AuCl 4 . FT-IR, 1 H NMR, thermogravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS) of the ruby red gold nanoparticles indicated the absence of the diazonium nitrogen and the presence of the organic shell C 8 F 17 -4-C 6 H 4 . Temperature-dependent Xray powder diffraction (TD-XRD) measurements showed intense cubic gold nanoparticle diffraction patterns in the temperature range 300−500 °C.The effective hydrodynamic size measured by a nanoparticle track analyzer (NTA) in ethanol is 45 nm, and the average core size estimated by transmission electron microscopy (TEM) is 3.2 ± 0.2 nm. The core−shell bonding is strong and is able to withstand prolonged sonication in ethanol and acetonitrile and indefinite exposure to ambient conditions in the solid state.

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We measured the near-field infrared response of MnPS3 in bulk, few-, and single-layer form and compared our findings with traditional far field vibrational spectroscopies, a symmetry analysis, and first principles lattice dynamics calculations. Trends in the Bu mode near 450 cm −1 are striking, with the disappearance of this structure in the thinnest sheets. Combined with the amplified response of the activated Ag mode and analysis of the Au + Bu features, we find that symmetry is unexpectedly increased in few-and single-sheet MnPS3 due to a restoration of the threefold axes of rotation. Monoclinicity in this system is therefore a consequence of the long-range stacking pattern and temperature rather than local structure.

We combine Raman scattering spectroscopy and lattice dynamics calculations to reveal the fundamental excitations of the intercalated metal monolayers in the Fe x TaS 2 (x = 1/4, 1/3) family of materials. Both in-and out-of-plane modes are identified, each of which has trends that depend upon the metal−metal distance, the size of the van der Waals gap, and the metal-to-chalcogenide slab mass ratio. We test these trends against the response of similar systems, including Crintercalated NbS 2 and RbFe(SO 4 ) 2 , and demonstrate that the metal monolayer excitations are both coherent and tunable. We discuss the consequences of intercalated metal monolayer excitations for material properties and developing applications.