XPS study of structural transformations in some Ni complexes

Abstract

X‐ray photoelectron spectroscopy investigations of Ni(LCH3)3(Piv)2 (1), [Ni(LCH3)2]2(Piv)2) (2), and [Ni(LCH3)2]2(CH3COO)2] (3) complexes, where LCH3—k2‐1,2‐diamino‐4,5‐dimethylbenzene‐bis(k1‐diamino‐4,5‐dimethylbenzene) and Piv—(CH3)3CCOO, are reported and discussed. The photoelectron spectra are sensitive to the temperature of the samples and evidence on structural conformations.

Amine Functionalized Metal–Organic Framework Coordinated with Transition Metal Ions: d–d Transition Enhanced Optical Absorption and Role of Transition Metal Sites on Solar Light Driven H2 Production

“…This indicates that the coordination of Co 2+ and Ni 2+ metal ions to –NH 2 group could not change the oxidation states due to less coordination tendency of –NH 2 group. However, the Cu‐MOF exhibits the peaks for both Cu 2+ (955.34 and 935.06 eV) and Cu + (952.82 and 933.01 eV) oxidation states . The existence of both +2 and +1 states can be ascribed to: i) the effective coordination of –NH 2 group through non‐bonded electrons of nitrogen and ii) the formation oxide layer on Ti‐MOF surface, which further confirms the existence of CuO x after the coordination as supported by XRD analysis.…”

“…However, the Cu-MOF exhibits the peaks for both Cu 2+ (955.34 and 935.06 eV) and Cu + (952.82 and 933.01 eV) oxidation states. [46][47][48] The existence of both +2 and +1 states can be ascribed to: i) the effective coordination of -NH 2 group through non-bonded electrons of nitrogen and ii) the formation oxide layer on Ti-MOF surface, which further confirms the existence of CuO x after the coordination as supported by XRD analysis. Moreover, the coordination environment of M 2+ ions with Ti-MOF was also studied by electron paramagnetic resonance (EPR) analysis (Figure 5d).…”