A New Approach to the Synthesis of Nanocrystalline Cobalt Boride in the Course of the Thermal Decomposition of Cobalt Complexes [Co[sub.6]][sup.2+] with Boron Cluster Anions

• Published in: Molecules (Basel, Switzerland) Vol. 28; no. 1
• Main Authors: Malinina, Elena A, Myshletsov, Ivan I, Buzanov, Grigorii A, Kubasov, Alexey S, Kozerozhets, Irina V, Goeva, Lyudmila V, Nikiforova, Svetlana E, Avdeeva, Varvara V, Zhizhin, Konstantin Yu, Kuznetsov, Nikolay T
• Format: Journal Article
• Language: English
• Published: MDPI AG 01.01.2023
• Subjects: Analysis; Cobalt; Nanocrystals; Properties; Russia
• ISSN: 1420-3049; 1420-3049
• DOI: 10.3390/molecules28010453

In the course of the study, nanocrystalline cobalt monoboride was prepared by thermal decomposition of precursors [Co(DMF)[sub.6] ][An], where [An] = [B[sub.12] H[sub.12] ][sup.2−] (1), [trans-B[sub.20] H[sub.18] ][sup.2−] (2) or [B[sub.10] Cl[sub.10] ][sup.2−] (3) in an argon atmosphere. Three new salt-like compounds 1–3 were prepared when Co(NO[sub.3] )[sub.2] was allowed to react with (Et[sub.3] NH)[sub.2] [An]. Compound 1 is new; the structures of compounds 2 and 3 have been previously reported. Samples 1–3 were annealed at 900 °C in argon to form samples 1a–3a, which were characterized by single crystal XRD for 1 and powder XRD for 1–3. Powder XRD on the products showed the formation of BN and CoB for 1a in a 1:1 ratio; 2a gave a higher CoB:BN ratio but an overall decreased crystallinity. For 3a, only CoB was found. IR spectra of samples 1a–3a as well as X-ray spectral fluorescence analysis for 3a confirmed these results. The nanoparticular character of the decomposition products 1a–3a was shown using TEM; quite small particle sizes of about 10–15 nm and a quite normal size distribution were found for 1a and 2a, while the decomposition of 3 gave large particles with 200–350 nm and a broad distribution.