Determination of Large Zero-Field Splitting in High-Spin Co(I) Clathrochelates

Joscha Nehrkorn; Sergey L Veber; Liudmila A Zhukas; Valentin V Novikov; Yulia V Nelyubina; Yan Z Voloshin; Karsten Holldack; Stefan Stoll; Alexander Schnegg

doi:10.1021/acs.inorgchem.8b02670

Determination of Large Zero-Field Splitting in High-Spin Co(I) Clathrochelates

Inorg Chem. 2018 Dec 17;57(24):15330-15340. doi: 10.1021/acs.inorgchem.8b02670. Epub 2018 Nov 29.

Authors

Joscha Nehrkorn^{1

2

3

4}, Sergey L Veber^{5

6}, Liudmila A Zhukas^{5

6}, Valentin V Novikov⁷, Yulia V Nelyubina⁷, Yan Z Voloshin⁷, Karsten Holldack⁸, Stefan Stoll², Alexander Schnegg^{3

4}

Affiliations

¹ Department of Chemistry, Institute for Inorganic and Applied Chemistry , University of Hamburg , Martin-Luther-King-Platz 6 , D-20146 Hamburg , Germany.
² Department of Chemistry , University of Washington , Box 351700, Seattle , Washington 98195-1700 , United States.
³ Berlin Joint EPR Laboratory, Institut für Nanospektroskopie , Helmholtz-Zentrum Berlin für Materialien und Energie , Kekuléstr. 5 , D-12489 Berlin , Germany.
⁴ Max Planck Institute for Chemical Energy Conversion , Stiftstr. 34-36 , D-45470 Mülheim an der Ruhr , Germany.
⁵ International Tomography Center , Siberian Branch of the Russian Academy of Sciences , Institutskaya str. 3a , 630090 Novosibirsk , Russia.
⁶ Novosibirsk State University , Pirogova str. 1 , 630090 Novosibirsk , Russia.
⁷ Nesmeyanov Institute of Organoelement Compounds , Russian Academy of Sciences , Vavilova str. 28 , 119991 Moscow , Russia.
⁸ Institut für Methoden und Instrumentierung der Forschung mit Synchrotronstrahlung , Helmholtz-Zentrum Berlin für Materialien und Energie , Albert-Einstein-Str. 15 , D-12489 Berlin , Germany.

PMID: 30495930
DOI: 10.1021/acs.inorgchem.8b02670

Abstract

Zero-field splitting (ZFS) of three high-spin Co(I) ( S = 1) clathrochelate complexes was determined by frequency-domain Fourier-transform THz-EPR (FD-FT THz-EPR). The following axial and rhombic ZFS values ( D and E, respectively) were determined: [N( n-Bu)₄]Co^I(GmCl₂)₃(BPh)₂ (1, D/ hc = +16.43(1) cm^-1, E/ hc = 0.0(1) cm^-1), [P(Me₂N)₄]Co^I(GmCl₂)₃(BPh)₂ (2, D/ hc = +16.67(4) cm^-1, E/ hc = 0.0(1) cm^-1), and [P(C₆H₅)₄]Co^I(GmCl₂)₃(BPh)₂ (3, D/ hc = +16.72(2) cm^-1, E/ hc = 0.24(3) cm^-1). Complementary susceptibility χ T measurements and quantum chemistry calculations on 1 revealed hard-axis-type magnetic anisotropy and allowed for a correlation of ZFS and the electronic structure. Increased rhombicity of 3 as compared to 1 and 2 was assigned to symmetry changes of the ligand structure induced by the change of the counterion. 1 and 3 exhibited temperature-dependent ZFS values. Possible reasons for this phenomenon, such as structural changes and weak chain-like intermolecular antiferromagnetic interactions, are discussed.