Ji-Dong Leng

We report the synthesis, structural characterization, and magnetic properties of three pentacoordinate Co(II) complexes [CoX(dppb)₂]X (X = Cl (1Cl), Br (2Br), and I (3I)) supported by the bidentate phosphine ligand 1,2-bis(diphenylphosphino)benzene (dppb). Single-crystal X-ray diffraction reveals that all three complexes adopt similar vacant octahedron (C_4v) geometries with the halide ligand in one axial position. Magnetic studies demonstrate that these complexes exhibit field-induced slow magnetic relaxation behaviors, with positive D values of 25.3(2), 21.6(1), and 19.4(2) cm⁻¹ for 1Cl, 2Br, and 3I, respectively. Detailed analysis of the relaxation dynamics reveals that Raman processes dominate at higher temperatures, with systematic variations in relaxation parameters across the series. The systematic variations in magnetic anisotropy and slow magnetic relaxation behaviors of the three complexes correlate with the decreasing electronegativity of the halide ligands.

This work reports three six-coordinate lanthanide complexes showing field-induced slow magnetic relaxation, where the unique cis-arrangement of chloride ligands leads to distinct magnetic relaxation dynamics.

A novel series of molecular Co(II) complexes with aza‐bridged bis‐1,10‐phenanthroline (bpa) ligands have been synthesized and reported for the catalytic hydrogen evolution reaction (HER). Various nitrogen donor substituents are introduced at the aza‐bridge of the bis‐phenanthroline moieties render intramolecular basic sites in the complexes’ second‐coordination sphere. Modifying the pendant nitrogen donor significantly influences the catalytic HER performance. Among these, the cobalt complex with the (2‐pyridyl)methyl substituted bis‐phenanthroline ligand (L3) exhibits the most photocatalytic HER efficiency in both organic and aqueous media. Under optimized conditions with [Ru(bpy)₃]²⁺ as a sensitizer and ascorbic acid as an electron donor, [Co^II(L3)(TfO⁻)₂] achieves an initial turnover frequency (TOF) of 1882±65 h⁻¹ per catalyst and a turnover number (TON) of 4842±122 in a 3 hour reaction period under the irradiation of visible light. Combined experimental and theoretical evidences illustrate that phenanthroline moieties of the bpa ligands act as electron mediators during the HER catalysis, while the pendant nitrogen donor substituents mediate proton transfer. This work provides a unique example for understanding the activity‐structure relationship of homogeneous HER catalyst concerning the redox‐active properties and second coordination sphere basic sites of organic ligand platforms.

This study presents the synthesis, structural characterization, and evaluation of the photocatalytic performance of two novel one-dimensional (1D) lead(II) bromide hybrids, [Co(2,2′-bpy)₃][Pb₂Br₆CH₃OH] (1) and [Fe(2,2′-bpy)₃][Pb₂Br₆] (2), synthesized via solvothermal reactions. These compounds incorporate transition metal complex cations as structural directors, contributing to the unique photophysical and photocatalytic properties of the resulting materials. Single-crystal X-ray diffraction analysis reveals that both compounds crystallize in monoclinic space groups with distinct 1D lead bromide chain configurations influenced by the nature of the complex cations. Optical property assessments show band gaps of 3.04 eV and 2.02 eV for compounds 1 and 2, respectively, indicating their potential for visible light absorption. Photocurrent measurements indicate a significantly higher electron–hole separation efficiency in compound 2, correlated with its narrower band gap. Additionally, photocatalytic evaluations demonstrate that while both compounds degrade organic dyes effectively, compound 2 also exhibits notable hydrogen evolution activity under visible light, a property not observed in 1. These findings highlight the role of metal complex cations in tuning the electronic and structural properties of lead(II) bromide hybrids, enhancing their applicability in photocatalytic and optoelectronic devices.

Two Ln ^III complexes Ln(HTMSA) ₃ (H ₂ O) ₂ ·5.5H ₂ O (Ln = Dy (1) and Tb (2)) and two Mn ^II –Ln ^III clusters [Mn(H ₂ O) ₆ ][MnLn ₂ (TTMSA) ₄ (HTTMSA) ₂ (H ₂ O) ₆ ]·4H ₂ O (Ln = Dy (3) and Tb (4)) have been synthesized and structurally characterized.

Based on the uncommon Kramers ions Ce^III, Sm^III and Yb^III, three mononuclear complexes toward single-ion magnets were obtained and fully characterized.

Three stereoisomeric 2D and 3D coordination polymers based on six-coordinate Dy( iii ) ions with facial or meridional coordination environments were isolated. Their different configurations lead to their distinct magnetic behaviours.

A D_5h equatorial compressed ligand field of the central Ln^III ion is achieved. The samarium complex is the first Sm^III mono-nuclear complex with slow magnetic relaxation. The Dy^III analogue, in contrast, relaxes much faster

Two isostructural mononuclear Co^II complexes, [Co(xantpo)(NCE)₂] (E=S (1) and O (2); xantpo=9,9‐dimethyl‐4,5‐bis(diphenylphosphoryl) xanthene), supported by a bidentate phosphine oxide ligand are reported. The cobalt complexes exhibit characteristic tetrahedral structures coordinated with two oxygen and two nitrogen atoms. Magnetic property measurements show their similar static magnetic behaviours but very different dynamic magnetic behaviours. Both complexes show field‐induced slow magnetic relaxation behaviours, but the relaxation of 2 is much slower than that of 1. Fittings to the magnetic data and ab initio CASSCF calculations reveal significant changes in the zero field splitting (ZFS) parameters (D and E), which can be attributed to the small geometrical changes of the Co ions and the different ligand field strength of the two terminal ligands.

New heterometallic rings containing Cr(iii) and tetravalent metals are reported, including a {Cr₆Th₂} cage.