Abstract
New complexes of manganese(II) hexafluoroacetylacetonate [Mn(hfac)2] with 2-(1-R-3-pyrazol-4-yl)-4,4,5,5-tetramethyl-2-imidazoline-3-oxide-1-oxyl (R = CHF2, CH2CH2F, CH2CHF2 or CH2CF3) were synthesised and characterised structurally and magnetically. All complexes were prepared under similar conditions. Nonetheless, their crystal structures were considerably different. Depending on the structure of fluorinated alkyl substituent R, the complexation reaction led to complexes of three types: chain-polymeric complexes with the head-to-head or head-to-tail motif and complexes of molecular structure. All complexes show strong antiferromagnetic behaviour in a high-temperature region (150–300 K) and weak ferro- or antiferromagnetic exchange interactions at low temperatures. The stronger antiferromagnetic exchange, −101.7 ± 1.5 or −136 ± 10 cm−1, −82.3 ± 1.3 cm−1 and −87.4 ± 1.3 cm−1, was attributed to the magnetic interaction in three- or two-spin clusters: {>N∸O–Mn2+–O∸N<} or {>N∸O–Mn2+}, respectively. The weaker antiferromagnetic interaction, −0.005, between three-spin clusters or ferromagnetic interactions, 0.18–0.81 cm−1, between two-spin clusters are realised through the pyrazole ring or intermolecular contacts.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.