Title

Wheel-Shaped Mn16 Single-Molecule Magnets

Abstract

The syntheses, structures, and magnetic properties of two new single-stranded hexadecanuclear manganese wheels [Mn16(CH 3COO)8(CH3CH2CH2COO) 8(teaH)12]·10 MeCN (1·10 MeCN) and [Mn 16((CH3)2CHCOO)16(teaH) 12]·4CHCl3 (2·4CHCl3), where teaH2- is the dianion of triethanolamine, are reported. 1 crystallizes in the tetragonal I41/a space group [a = b = 33.519(4) Å and c = 16.659(2) Å]. 2 crystallizes in the monoclinic C2/c space group [a = 21.473(5), b = 26.819(6), c = 35.186(7), and β = 93.447(5)°]. Both complexes consist of 8 Mn(II) and 8 Mn(III) ions alternating in a wheel-shaped topology with 12 monoprotonated triethanolamine ligands. Variable-temperature direct current (DC) magnetic susceptibility data were collected in 1 T, 0.1 and 0.01 T fields, and in the 1.8-300 K temperature range for 1 and 2. Variable-temperature variable-field DC magnetic susceptibility data were obtained in the 1.8-10 K and 0.1-5 T ranges and least-squares fitting of these reduced magnetization versus H/T data indicates a S = 13 ground-state for 1 and 2. Single-crystal magnetization hysteresis measurements were performed in a 0.04-1 K temperature range for complex 2. Hysteresis loops were observed that showed a temperature dependence, which indicates that 2 exhibits magnetization relaxation and is a SMM. Both 1 and 2 show frequency-dependent out-of-phase signals in the AC susceptibility measurements, collected in a temperature range of 1.8-5 K and in the frequency range of 50-10 000 Hz. Extrapolation of the in-phase component of the AC susceptibility data to 0 K indicates an S = 12 ground state for 1 and an S = 11 ground-state for 2. Complex 1 has the highest-spin ground state reported to date for a single-stranded manganese wheel and is likely to be an SMM based on a frequency-dependent out-of-phase signal in the AC susceptibility. The AC susceptibility as well as magnetization hysteresis data for 2 confirm that this species is an SMM. © 2008 American Chemical Society.

Publication Date

7-21-2008

Publication Title

Inorganic Chemistry

Volume

47

Issue

14

Number of Pages

6245-6253

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1021/ic800277j

Socpus ID

48649097065 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/48649097065

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