Computational and Experimental Determination of the Electronic Structure and Optical Properties of Three-Dimensional Zn[M(CN)4] Tetracyanates (M = Ni, Pd, and Pt)

• Published in: Journal of physical chemistry. C 2023-08, Vol.127 (32), p.16071-16080
• Main Authors: Mojica, Rodrigo, Torres, Ana Elizabeth, Lemus-Santana, Ana Adela, Borja-Urby, Raúl, Avila, Yosuan, Reguera, Edilso
• Format: Article
• Language: English
• Subjects: C: Physical Properties of Materials and Interfaces
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/acs.jpcc.3c03013

The electronic structure of cyanide-based Zn­[M­(CN)4] (M = Ni, Pd, and Pt) coordination polymers is studied by means of spectroscopic techniques and DFT-based computational calculations. The observed different ν­(CN) band shifts to higher frequencies when the inner metal from the tetracyanate moiety [M­(CN)4] changes from Ni to Pt and Ni to Pd as a consequence of the charge distribution produced by the π back-bonding phenomena and the competition between the polarization powers from M and Zn. This is evidenced by infrared, Raman, and UV–vis spectroscopic techniques in conjunction with hybrid HSE06 calculations. The sample characterization was completed from XPS spectra and HR-TEM images. The electronic structure was also studied by the computed lm-decomposed density of states and band dispersion diagrams. The nature of the valence band top and conduction band bottom is described by d-M, p-M, p-nitrogen, and c-carbon hybridized orbitals. The electronic behavior of the former solids strongly differs from that of the isolated square-planar tetracyanates, but the HOMO–LUMO electronic transitions are still dominated by the tetracyanate [M­(CN)4] and π–π* interactions in the three cases. Band gap energy values are reported for the three studied semiconductors, and the internal metal effect is analyzed. The indirect nature of the electronic transitions associated with the gap is discussed, and the values of the effective and reduced masses are reported.