Atomically Precise Platinum Carbonyl Nanoclusters: Synthesis, Total Structure, and Electrochemical Investigation of [Pt27(CO)31]4– Displaying a Defective Structure

• Published in: Inorganic chemistry 2022-08, Vol.61 (32), p.12534-12544
• Main Authors: Cesari, Cristiana, Berti, Beatrice, Funaioli, Tiziana, Femoni, Cristina, Iapalucci, Maria Carmela, Pontiroli, Daniele, Magnani, Giacomo, Riccò, Mauro, Bortoluzzi, Marco, Vivaldi, Federico Maria, Zacchini, Stefano
• Format: Article
• Language: English
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/acs.inorgchem.2c00965

The molecular Pt nanocluster [Pt27(CO)31]4– (1 4– ) was obtained by thermal decomposition of [Pt15(CO)30]2– in tetrahydrofuran under a H2 atmosphere. The reaction of 1 4– with increasing amounts of HBF4 ·Et2O afforded the previously reported [Pt26(CO)32]2– (3 2– ) and [Pt26(CO)32]− (3 – ). The new nanocluster 1 4– was characterized by IR and UV–visible spectroscopy, single-crystal X-ray diffraction, direct-current superconducting quantum interference device magnetometry, cyclic voltammetry, IR spectroelectrochemistry (IR SEC), and electrochemical impedance spectroscopy. The cluster displays a cubic-close-packed Pt27 framework generated by the overlapping of four ABCA layers, composed of 3, 7, 11, and 6 atoms, respectively, that encapsulates a fully interstitial Pt4 tetrahedron. One Pt atom is missing within layer 3, and this defect (vacancy) generates local deformations within layers 2 and 3. These local deformations tend to repair the defect (missing atom) and increase the number of Pt–Pt bonding contacts, minimizing the total energy. The cluster 1 4– is perfectly diamagnetic and displays a rich electrochemical behavior. Indeed, six different oxidation states have been characterized by IR SEC, unraveling the series of 1 n – (n = 3–8) isostructural nanoclusters. Computational studies have been carried out to further support the interpretation of the experimental data.