Click chemistry as a route to the synthesis of structurally new and magnetically interesting coordination clusters: a {Ni} complex with a trapezoidal prismatic topology

The synthesis of a new {Ni₈} cluster bearing tetrazolate- and azido-bridging ligands, and supported by chelating α-methyl-2-pyridine-methanol (mpmH) groups, is described herein. The reported compound has a unique trapezoidal prismatic topology, resulting from an unexpected in situ click reaction between the MeCN reaction solvent and the N₃^- ions under mild, room-temperature conditions. Such a click chemistry approach to the preparation of 0-D compounds is relatively unexplored and represents a fruitful strategy for the synthesis of new coordination clusters and molecule-based magnetic materials.

Single-chain magnets assembled in cobalt(ii) metal–organic frameworks

This feature article discusses the advantages, progress and prospects of constructing single-chain magnets in metal–organic frameworks.

Ferromagnetically coupled dinuclear MII complexes based on a boratriazine ligand framework

A boratriazine ligand, which incorporates attractive features from both bodipy and terpy, has been used to synthesize [Fe2II(μ1,1-N3)2(Py2F2BTA)2(N3)2] (1) and [Co2II(μ1,1-N3)2(Py2F2BTA)2(N3)2] (2). Both 1 and 2 feature a double end-on azido bridging motif, which promotes ferromagnetic interactions between the metal centres. Indeed, 1 represents the first report of a dinuclear FeII complex with this bridging mode exhibiting J = 5.7(9) cm-1 and D = -6.0(4) cm-1, while the isostructural Co analogue shows J = 7.1(9) cm-1 and D = 17.3(9) cm-1.

Strong ferromagnetic exchange coupling in a {Ni} cluster mediated through an air-stable tetrazine-based radical anion

A planar tetradentate 3,6-bis(2-pyrimidyl)-1,2,4,5-tetrazine (BpymTz) templating chelate affords the formation of an unprecedented BpymTz˙^- radical anion bridged {Ni} complex. Detailed magnetic measurements performed on the isolated air stable [Ni(BpymTz˙^-)Cl₆(DMF)₈]Cl·0.5(H₂O) compound reveal strong ferromagnetic Ni^II-BpymTz˙^- interactions with a coupling constant of J = 98.84 cm^-1.

The structure and magnetism of mono- and di-nuclear Ni(ii) complexes derived from {N3O}-donor Schiff base ligands

Some mononuclear and dinuclear Ni(ii) complexes with tetradentate Schiff base ligands exhibit zero-field splitting and ferromagnetic coupling, respectively.

Hydrolytically active tetranuclear [NiII2]2 complexes: synthesis, structure, spectroscopy and phosphoester hydrolysis

Hydrolytically active three tetranuclear nickel(ii) complexes of a new symmetrical μ-bis(tetradentate) ligand, H₅chdp were prepared and their catalytic activity toward the phosphoester hydrolysis was examined.

Recent developments in Cope-type hydroamination reactions of hydroxylamine and hydrazine derivatives

Cope-type hydroaminations are versatile for the direct amination of alkenes, alkynes and allenes using hydroxylamines and hydrazine derivatives. These reactions occur via a concerted, 5-membered cyclic transition state that is the microscopic reverse of the Cope elimination. This article focuses on recent developments, including intermolecular variants, directed reactions, and asymmetric variants using aldehydes as tethering catalysts, and their applications in target-oriented synthesis.

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.

Unexpected metal ion-assisted transformations leading to unexplored bridging ligands in NiII coordination chemistry: the case of PO3F2− group

The bridging potency of the O-rich PO₃F²⁻ group in Ni^II/oximate chemistry has been studied leading to interesting coordination compounds and revealing an unprecedented PO₃F²⁻ to P₂O₅F₂²⁻in situ transformation.

Novel Co-based metal-organic frameworks and their magnetic properties using asymmetrically binding 4-(4'-carboxyphenyl)-1,2,4-triazole

Two novel Co-based metal-organic frameworks (MOFs) were synthesised and characterised using an asymmetrically binding ligand, 4-(4'-carboxyphenyl)-1,2,4 triazole (Hcpt). The isolated [Co3(II)(μ3-O)(OH)(cpt)3(H2O)2]n·xH2O·yDMF, Co-MOF1, exhibits a rhombohedral crystal structure (space group, P63/mc), with a trinuclear cobalt core that resembles the MIL88 series. This MOF shows paramagnetic behaviour down to 2 K with no saturation of magnetisation up to 7 T. This is presumably due to a geometrically frustrated triangular arrangement of Co spins. The two-dimensional complex, [Co(II)(cpt)(N3)]n, Co-MOF2, crystallises in a monoclinic crystal system (space group, C2/m). The magnetic measurements reveal metamagnetic behaviour for this complex with a critical field in the range of 700-1000 Oe.