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A high-nuclearity {Ni 18 } complex (1) with a unique 'flying saucer' motif has been prepared from the organic chelate, α-methyl-2-pyridine-methanol (mpmH), in conjunction with bridging azido (N 3 - ) and peroxido (O 2 2- ) ligands. Magnetic susceptibility measurements revealed the presence of both ferro- and antiferromagnetic exchange interactions between the metal centres in 1, and the stabilization of spin states with appreciable S values at two different temperature regimes. The end-on bridging azido and alkoxido groups are in all likelihood the ferromagnetic mediators, while the η 3 :η 3 } nanosized cluster behaves as a single-molecule magnet, exhibiting magnetic hysteresis at low temperatures and two relaxation processes at 15 K and 1.3 K, a very rare phenomenon in polynuclear magnetic 3d-metal clusters.6 -bridging peroxides most likely promote the antiparallel alignment of the metals' spin vectors, yielding an overall non-zero spin ground state for the centrosymmetric compound 1. Furthermore, the {Ni 18 } nanosized cluster behaves as a single-molecule magnet, exhibiting magnetic hysteresis at low temperatures and two relaxation processes at 15 K and 1.3 K, a very rare phenomenon in polynuclear magnetic 3d-metal clusters., (© 2024 The Author(s). Chemistry - A European Journal published by Wiley-VCH GmbH.)

The reaction of the NIT-2Py-3Py nitronyl nitroxide radical (NIT-2Py-3Py: 2-(2′,3′-bipyridine)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) containing two additional pyridine units with Ln(hfac)3·2H2O (hfac: hexafluoroacetylacetonate) gave rise to two one-dimensional chains [Ln(hfac)3(NIT-2Py-3Py)]n (Ln = GdIII1, NdIII2) and a trinuclear complex [Dy3(hfac)9(NIT-2Py-3Py)2] (3). In complexes 1 and 2, the NIT-2Py-3Py radicals are ligated to the LnIII ions in a "head-to-tail" mode to form zigzag chains. Complex 3 exhibits a linear trinuclear structure composed of one Dy(hfac)3 with two coordinated pyridine groups and two {DyIII–NIT radical} chelating units. Magnetic measurements indicate that the trinuclear Dy derivative shows magnetic relaxation characteristics, featuring an energy barrier of reversal of magnetization Ueff/kB of 22.9 K. [ABSTRACT FROM AUTHOR]

Starting from the alkyne complex Cp2Zr(py)(η2-Me3SiC2SiMe3) (Cp = η5-cyclopentadienyl, py = pyridine), the synthesis and complete characterisation of a zirconocene(IV) triazenido hydride complex and its use in the activation of small molecules is reported. The reaction with CO2 led to the formation of a zirconocene(IV) triazenido-formate complex, which was further investigated for its stability towards different bases with respect to the formation of formic acid. The experimentally observed reaction pathway was investigated computationally using DFT methods, revealing the favourable role of pyridine coordination in the hydrogen transfer from the triazene to the alkyne unit of the zirconocene reagent. [ABSTRACT FROM AUTHOR]

We report a continuous flow approach generating bicyclic cyclobutanes from unactivated alkenes in a metal-free manner that is inspired by the Kochi–Salomon reaction. A filtered Hg-lamp in combination with a simple flow set-up and acetone as UV light-absorbing co-solvent are crucial for this method thus showcasing attractive features for further exploitations. [ABSTRACT FROM AUTHOR]

A relatively unexplored approach in heterometallic chemistry of transition metals and lanthanides has been developed toward the controlled synthesis of a new family of linear heterotrinuclear Ln(III)-Pd(II)-Ln (III) complexes with the general formula [Ln2Pd(pao)2(NO3)6(MeOH)2(H2O)2]·[Pd(pao)2]4, where LnIII = DyIII (2), GdIII (3), ErIII (4) and YbIII (5). This strategy was based on the diamagnetic 'metalloligand' [Pd(pao)2] (1), where pao- is the anion of 2-pyridinealdoxime, containing two dangling oximate O-atoms which were trans to each other and available for binding with oxophilic lanthanide ions. Because of their transconfiguration, the [Pd(pao)2] 'metalloligand' was able to direct the binding of two {Ln(NO3)3(MeOH)(H2O)} units on opposite sites, thus yielding the reported trinuclear {Ln-Pd-Ln} clusters. Complexes 2-5 constitute a new family of trinuclear heterometallic {Ln2Pd} species, and they represent the first examples of a directional assembly approach towards the coordination of 4f-metal ions. Compounds 2 and 5 exhibit out-of-phase signals under applied dc fields of 300 and 2000 Oe, respectively, characteristics of the slow magnetization relaxation, albeit with very small energy barriers for the magnetization reversal. This was due to the combined onset of fast quantum tunneling and the weak crystal field effects induced by the coordinated ligands. The combined results highlight the potential of using the 'metal complexes as ligands' method to deliberately prepare heterometallic PdII-LnIII complexes with unique structural and interesting physicochemical (magnetic, optical, catalytic) properties. [ABSTRACT FROM AUTHOR]

The prominence of binuclear, bimetallic catalysts underlines the need for the design and development of diverse bifunctional ligand frameworks that exhibit tunable electronic and structural properties. Such strategies enable metal-metal and ligand-metal cooperation towards catalytic applications, improve catalytic activity, and are essential for advancing multi-electron transfers for catalytic application. In this work we present the synthesis, crystal structure, and photocatalytic properties of a binuclear Ni(II) complex, [Ni 2 (1,10-phenanthroline) 2 (2-sulfidophenolate) 2 ] (1). Complex 1 crystallizes in the centrosymmetric triclinic system (P-1) showing extensive intra- and inter- non-coordinated interactions. 1 is employed as a catalyst for light driven hydrogen evolution. Its catalytic efficiency in a noble-metal-free photo-driven system using fluorescein as photosensitizer and triethanolamine as the electron donor, reaches TON 2900, threefold the efficiency of the corresponding homoleptic mononuclear complex [Ni(2-sulfidophenolate) 2 ]. Efficiency rises up to 9000 TONs when thioglycolic-coated CdTe quantum dots are used as photosensitizers in the presence of ascorbic acid at pH 4.5. UV-Vis spectroscopy, dynamic light scattering techniques, and Hg-poisoning measurements reveal that 1 maintains its molecular structure during catalysis. Electrochemical studies in DMF with TFA as the proton source were also performed for the elucidation of the mechanism of its catalytic action and its stability, suggesting that the proximity of two nickel ions plays a part in the increased catalytic activity, facilitating hydrogen evolution., (© 2025 The Author(s). Chemistry - A European Journal published by Wiley-VCH GmbH.)