Crystal Structures and Magnetic and Ferroelectric Properties of Chiral Layered Metal−Organic Frameworks with Dicyanamide as the Bridging Ligand

Pyridine alcohols: New applications reviving interest in metal complexes of a classical ligand

Pyridine-based alcohols and their metal complexes show unique characteristics, such as redox activity, variable coordination modes, and reactivity towards organic substrates, resulting in multifaceted properties and diverse applications. This review explores the structural properties of these ligands when coordinated to metal ions, particularly focusing on their ability to form mononuclear and polynuclear complexes with transition metals such as copper, manganese, nickel, and cobalt. Moreover, square planar complexes with silver, platinum, palladium, and gold are discussed as well. Structural studies have revealed various coordination geometries of these complexes, providing insights into their potential applications in various fields. We focus mainly on recent literature (2014-2024) and describe the structural and biological effects of the complexes. Despite the seeming obscurity of pyridine alcohol derivative ligands, we wish to emphasize their potential and the significant applications reported, highlighting the renewed interest in synthesizing coordination complexes with various metal ions.

{Ni4} Cubanes from enantiomerically pure 2-(1-hydroxyethyl)pyridine ligands: supramolecular chirality

Homometallic {NiII4} cubane-like clusters with a rare chiral core have been prepared via the employment of enantiomerically pure 2-(1-hydroxyethyl)pyridine (Hmpm). Comparison with the achiral cubanes derived from the related 2-pyridinemethanol (Hpym) ligand reveals drastic structural changes as a consequence of the transfer of chirality from the ligands to the whole structure. Their magnetic properties have been related to the structural features of their cubane-type cores.

Luminescent metal organic frameworks for sensing and gas adsorption studies

Two three-dimensional metal organic frameworks (LZn and LCd) were synthesized solvothermally for sensing of nitro phenolic explosives and gas adsorption studies. LZn showed selectivity towards N₂ gas at 77 K.

A series of novel cadmium(ii) coordination polymers with photoluminescence and ferroelectric properties based on zwitterionic ligands

Herein, a series of Cd(ii) compounds were obtained by using a zwitterionic ligand (H₃LBr₃) and an aromatic secondary ligand (H₄BTC).

Copper(ii) cubanes with a {Cu4O} core and well defined S = 1 ground state

Three copper cubanes with the unusual S = 1 ground state have been characterized and their magnetic properties rationalized as a function of the asymmetry of the {Cu₄O₄} cage and correlated with the Cu–O–Cu bond angles.

Solvent-dependent assemblies, structure diversities and magnetic properties of two homochiral Co(ii)/Na(i) coordination polymers

Two novel homochiral Co(ii)/Na(i) coordination polymers based on chiral tridentate S-H₃L ligand have been successfully synthesized and structurally characterized.

Butterfly-like enantiomerically homochiral {CoII6CoIII4} clusters exhibiting both slow magnetic relaxation and ferroelectric property

A pair of butterfly-like enantiomerically homochiral [Co^II₆Co^III₄] clusters with both slow magnetic relaxation behaviour and ferroelectric property was synthesized.

On the nature of the reversibility of hydration-dehydration on the crystal structure and magnetism of the ferrimagnet [MnII(enH)(H2O)][CrIII(CN)6].H2O

We report the synthesis, crystal structure, and thermal and magnetic properties of the two-dimensional achiral soft ferrimagnet [Mn(II)(enH)(H(2)O)][Cr(III)(CN)(6)].H(2)O (1), en = 1,2-diaminoethane, as well as the recyclability of the dehydration and rehydration and their influence on the crystal structure and its magnetic properties. Unlike [Mn(S-pnH)(H(2)O)][Cr(CN)(6)].H(2)O (2S, pn = 1,2-diaminopropane), which is a chiral (P2(1)2(1)2(1)) enantiopure ferrimagnet (T(C) = 38 K), 1 crystallizes in the achiral orthorhombic Pcmn space group, having a similar two-dimensional square network of Mn-Cr with bridging cyanide, and 1 behaves also as a soft ferrimagnet (T(C) = 42 K). X-ray diffraction experiments on a single crystal of 1 indicate a transformation from a single crystal to an amorphous phase upon dehydrataion and partial recovery of its crystallinity upon rehydration. The dehydrated phase 1-DP exhibits long-range ordering at 75 K to a ferrimagnetic state and coercive field at 2 K of 100 Oe, which are a higher critical temperature and coercive field than for the virgin sample (H(C) = 60 Oe). Thermogravimetric analyses indicate that the crystallinity deteriorates upon hydration-dehydration cycling, with persistence toward the amorphous phase, as also seen by magnetization measurements. This effect is associated with an increase of statistical disorder inherent in the dehydration-rehydration process. X-ray powder diffraction suggests that 1-DP may retain order within the layers but loses coherence in the stacking of the layers.