Assembly of alternating spin-chains with magnetically anisotropic cobalt(II) dimers

Construction of magnet-type coordination polymers using high-spin {Ni4}-citrate cubane as secondary building units

A robust ferromagnetic secondary building unit based on {Ni₄}-citrate cubane is identified to be able to construct diverse structures while retaining the original magnetism.

Self-assembly of linear [Mn(II)2Mn(III)] units with end-on azido bridges: the construction of a ferromagnetic chain using ST = 7 high-spin trimers

The controlled organization of high-spin complexes into 1D coordination polymers is a challenge in molecular magnetism. In this work, we report a ferromagnetic Mn trimer Mn3(HL)2(CH3OH)6(Br)4·Br·(CH3OH)2 1 (H2L = 2-[(9H-fluoren-9-yl)amino]propane-1,3-diol) with the ground spin state of ST = 7 that can be assembled into a one-dimensional coordination chain [Mn3(HL)2(CH3OH)2(Br)4(N3)(H2O)·CH3OH]∞ 2 using azido bridging ligands. Interestingly, the ferromagnetic nature of 1 is well retained in 2. However, due to the negligible magnetic anisotropy in 1, both 1 and 2 do not show slow-relaxation of magnetization, which indicates that during the process of molecular assembly not only the intratrimer magnetic interaction but also the magnetic anisotropy of the trimer can be reserved.

Dynamic magnetism of an iron(II)-chlorido spin chain and its hexametallic segment

An air-stable iron(ii) chain compound [Fe(phen)(Cl)2]n (, phen = 1,10-phenanthroline) was prepared and exhibits intrachain ferromagnetic interactions as well as competing interchain antiferromagnetic interactions that are mediated by π-π stacking of the phen ligands, resulting in metamagnetic behaviour. The interchain interactions can be altered by changing the external magnetic field, and disparate magnetic dynamics was thus observed from zero to the critical field of 1500 Oe. Zero-field cooled (ZFC) and field-cooled (FC) magnetization and heat capacity measurements indicate that long-range antiferromagnetic ordering occurs at lower fields, and this ordering disappears when the external field is larger than 1500 Oe. The low-frequency ac susceptibility data are consistent with the exponential increase of the temperature-dependent dc data, indicating a Glauber-type dynamics under the field of 1500 Oe. Thus, is considered as a metamagnetic single-chain magnet. For further analysis, a discrete hexametallic segment of the chain, [Fe6(phen)6(Cl)12] (), was also isolated and was shown to possess a high-spin ground state and display slow magnetic relaxations like single-molecule magnets. Magnetic analysis using CONDON suggests weak ferromagnetic interactions between the metal centres. The polymeric compound can be viewed as being constructed using the hexametallic unit which is of a low energy barrier, suggesting the significance of intrachain ferromagnetic interactions in enhancing the spin-reversal energy barrier of the short chains.