The Effect of Crystal Packing and Re^IV Ions on the Magnetisation Relaxation of [Mn₆]‐Based Molecular Magnets

Abstract

The energy barrier to magnetisation relaxation in single-molecule magnets (SMMs) proffers potential technological applications in high-density information storage and quantum computation. Leading candidates amongst complexes of 3d metals ions are the hexametallic family of complexes of formula [Mn6O2(R-sao)6(X)2(solvent)y] (saoH2=salicylaldoxime; X=mono-anion; y=4–6; R=H, Me, Et, and Ph). The recent synthesis of cationic [Mn6][ClO4]2 family members, in which the coordinating X ions were replaced with non-coordinating anions, opened the gateway to constructing families of novel [Mn6] salts in which the identity and nature of the charge balancing anions could be employed to alter the physical properties of the complex. Herein we demonstrate initial experiments to show that this is indeed possible. By replacing the diamagnetic ClO4− anions with the highly anisotropic ReIV ion in the form of [ReIVCl6]2−, the energy barrier to magnetisation relaxation is increased by up to 30 %.

Self-assembly of the tetrachlorido(oxalato)rhenate(iv) anion with protonated organic cations: X-ray structures and magnetic properties

“…The g values calculated for 1 and 2 are in agreement with those previously reported for mononuclear Re IV complexes. 3,7-Please do not adjust margins Please do not adjust margins 36 The negative values of  confirm the presence of relatively strong antiferromagnetic exchange through intermolecular Re-Cl···Cl-Re pathways (see Fig. 8), with the shorter interactions in 2 resulting in stronger exchange.…”

Thioester-functionalised and oxime-based hexametallic manganese(iii) single-molecule magnets

“…The obtained J 1 , J 2 and g values result to be consistent with the torsion angles found in the crystal structures of 1 and 2, and agree with those previously reported for similar [Mn 6 ] systems. [12][13][14][15][16] In a previous work dealing with DFT studies on salicylamidoxime-based [Mn 6 ] complexes, 13c it was established that the critical angle where the exchange pathway between neighbouring Mn III ions switches from antiferromagnetic (J < 0) to ferromagnetic (J > 0) is ca. 27.0 , which is somewhat lower than that of the related salicylaldoxime-based [Mn 6 ] complexes.…”

“…The experimental data are given as reduced magnetisation in Fig. 5 [12][13][14][15][16] Besides the results obtained by tting the experimental data of the reduced magnetisation, ground state spin values of S ¼ 12 (1) and S ¼ 4 (2) were also obtained from dc susceptibility measurements. Indeed, plots of the energy versus total spin, extracted from the isotropic simulation of the magnetic susceptibility, are shown in Fig.…”

“…10 Oxime-based hexanuclear Mn III SMMs have intensively been studied in the eld of molecular magnetism. [12][13][14][15][16] In these systems, the magnetic exchange between Mn III ions depends basically on the Mn-N-O-Mn torsion angles, they possess generally spin ground states varying from 4 to 12, and the anisotropy energy barriers vary from 24 to 86 K. [12][13][14][15][16] Some of these [Mn III 6 ] SMMs have also been graed on Au surfaces and studied, as thiophene-carboxylate [Mn III 6 ] derivatives. 7,8 Nevertheless, no thioester-functionalised [Mn III 6 ] compound has been reported up to date.…”

Enhancement of Intermolecular Magnetic Exchange through Halogen···Halogen Interactions in Bisadeninium Rhenium(IV) Salts

“…[27][28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46] In particular, the simple hexahalorhenate(IV) salts [Re IV X6] 2-(X = F, Cl, Br, and I) of paramagnetic and diamagnetic cations generally show significant short-range intermolecular ferro-or antiferromagnetic interactions, which are mainly transmitted through relatively short intermolecular Re-X•••X-Re contacts, occasionally leading to collective magnetic phenomena such as ferromagnetism and spin canting (weak ferromagnetism). [47][48][49][50][51][52][53][54][55][56][57][58][59] Herein we report the synthesis and magneto-structural characterization of two novel Re IV compounds of general formula [H2ade]2[Re IV X6]X2•4H2O [H2ade 2+ = 9H-adenine-1,7-diium; X = Cl (1) and Br (2)]. 1 and 2 are the first paramagnetic salts based on diprotonated adenine.…”