Acylpyrazolone ligands: Synthesis, structures, metal coordination chemistry and applications

This review summarizes the literature on 4-acyl-5-pyrazolone ligands, their synthesis, characterization and coordination chemistry toward main group, transition, lanthanide and actinide metals and relevant applications of their metal complexes.     

Metallo‐Polymerization/‐Cyclization of a C16‐Bridged Di‐Terpyridine Ligand and Iron(II) Ions

Summary: The coordinative polymerization/cyclization of a flexible monodisperse di‐terpyridine ligand with iron(II ) chloride is reported. Matrix‐assisted laser desorption ionization time‐of‐flight (MALDI‐TOF) investigations showed the preferred formation of a [2 + 2] macrocycle, but also larger aggregates (cycles or linear oligomers) with up to 10 monomer units were found. Because of its C₁₆‐spacer, the solubility is sufficient for performing viscosity experiments in CHCl₃/MeOH solution. A viscosity titration revealed a maximum in viscosity at the 1‐to‐1 ratio of iron(II ) ions to di‐terpyridine‐ligands, which indicates the formation of extended oligomers, polymers, catenanes and/or cycles at that ratio.

Schematic representation of intra‐ and intermolecular metallo‐macrocycles.     

联三吡啶配体组装及其金属络合物性能*

金属-配体间的配位作用是超分子化学中最重要的相互作用之一,寡聚吡啶配体可以与许多过渡金属离子配位,形成具有独特磁、光物理和电化学性质的过渡金属配合物,因此联三吡啶配体过渡金属配合物性能研究引起化学家的广泛关注。本文系统综述了联三吡啶配体及其衍生物的组装策略及其过渡金属配合物的光化学与光物理性能,包括单极、二极及多极配体以及由这类配体组装得到的各种拓扑结构的单核、多核过渡金属配合物,如线型金属寡聚物、金属聚合物、金属大环化合物、有机金属树枝状化合物等,并介绍这些配合物在该领域研究和应用前景。     

Construction of a Hexameric Zn(II)‐metallomacrocycle and its Photo‐ and Electroluminescence Properties: [Zn6(O‐hexyl‐3,5‐bis(2,2′:6′,2″‐terpyridine)phenol)6(BF4)12]

Summary: An O‐hexyl‐3,5‐bis(terpyridine)phenol ligand has been synthesized and transformed into a hexagonal Zn(II)‐metallomacrocycle by a facile self‐assembly procedure capitalizing on terpyridine‐Zn(II)‐terpyridine connectivity. The structural composition was confirmed by NMR and mass spectral techniques; photo‐ and electroluminescence properties were also investigated. The OLED device shows green electroluminescent emission at 515 nm with a maximum luminance of 39 cd · m⁻² and maximum efficiency of 0.16 cd · A⁻¹.

Structure and electroluminescent properties of the metallomacrocycle investigated.     

Synthesis of A New Terpyridine Ligand Combined with Ruthenium(II) Complex and its Usage in the Stepwise Fabrication of Complex Polymer Wires on Gold

Summary: A ruthenium complex-combined terpyridine ligand, tpyRu(dpp)-(epe)- tpyPF₆, was synthesized. Stepwise coordination reactions at the gold surface using this ligand gave Co-Ru hetero-metal complex wires, [ 1Co1Ru ], which underwent reversible redox reactions of both redox complex units.     

Terpyridine Metal Complexes as Building Blocks for Supramolecular Assemblies and Polymers: Thermal Stabilities and Thin Film Preparation

5,5'-Dimethyl-2,2':6',2'-terpyridine complexes with various transition metal ions like Zn(II), Co(II), Mn(II) and Hg(II) were investigated concerning their thermal properties. A significant dependency of the thermal stability (5% weight loss) of the complexes depending on the kind of metal ion used could be observed ranging from 315 to 390 °C. Furthermore, self-assembled thin films of such metallo-supramolecular Hg(II) complexes were prepared and characterized by synchrotron based X-ray reflectivity and fluorescence techniques.     

Metallo‐Supramolecular Graft Copolymers: A Novel Approach Toward Polymer‐Analogous Reactions

A copolymer of poly(methyl methacrylate) with terpyridine units in the side chains was synthesized utilizing free‐radical polymerization. The free terpyridine units were complexed with several different terpyridineruthenium mono‐complexes, yielding metallo‐supramolecular graft copolymers. The materials obtained were characterized by means of NMR and UV‐vis spectroscopy as well as GPC. Characterization by thermal analysis revealed distinct differences between these new materials and the initial copolymer.     

Self-assembly of emissive metallocycles with tetraphenylethylene,BODIPY and terpyridine in one system

ABSTRACT

Tetraphenylethylene (TPE) related (supra)molecules have been intensively investigated due to their aggregation-induced emission (AIE) effect based on the restriction of intramolecular rotation (RIR). Meanwhile, boron-dipyrromethene (BODIPY) tends to emit intense fluorescence with high quantum yields. Herein, we combined TPE, BODIPY and terpyridine (TPY) into one system to study the emissive behaviour of organic building block as well as a self-assembled metallo-supramolecule. The TPY and BODIPY substituents with bulky sizes provide strong hindrance to restrict the rotation of the phenyl groups on TPE, leading to enhancement of emissive properties in both solution and aggregation states. Furthermore, the BODIPY-TPE-TPY ligand (L) was assembled with Zn (II) through coordination-driven self-assembly to form a cyclic dimer (D) with typical AIE characteristics.     

Chiral 3D Coordination Polymers Consisting of Achiral Terpyridyl Precursors: from Spontaneous Resolution to Enantioenriched Induction

A pair of enantiomers of three-dimensional (3D) chiral coordination polymers (CCPs) were successfully constructed by using achiral components 4,2′:6′,4′′-terpyridyl precursors and Cu²⁺ through spontaneous resolution ( 1 a ). By utilising feeding controlled chiral-templated induction and chiral auxiliary behaviour of optically pure camphor sulfonate (CSA), the enantioenriched ( 1 b-P and 1 b-M ) and CSA captured ( 1 c-P and 1 c-M ) CCPs were successfully synthesised, respectively. The chiral information of the corresponding products was confirmed by X-ray single crystal diffraction and solid-state CD spectra. Meanwhile, the formation processes of 1 b-P and 1 b-M were monitored through solution CD spectra, UV/Vis spectra and ESI-TOF MS. Based on these results, a reasonable chiral-templated induction mechanism of forming 1 b-P and 1 b-M was proposed.     

Chiral C1-symmetric 2,2′:6′,2′′-terpyridine ligands: Synthesis,characterization, complexation with copper(II), rhodium(III) and ruthenium(II) ions and use of the complexes in catalytic cyclopropanation of styrene

Three new optically pure C₁-terpyridine ligands (L1–3) were prepared and the copper(II) complexes, of formula [Cu(L)Cl₂], the rhodium(III) complexes, of formula [Rh(L)Cl₃], and the ruthenium(II) complexes, of formula cis- or trans-[Ru(L)(X)Cl₂] (X = DMSO or CO), were synthesized. Structures of a chiral C₁-ligand, a copper complex, a rhodium complex and a ruthenium DMSO complex were analysed using X-ray crystal structure analysis. The copper, rhodium and ruthenium complexes were shown to be precursors of catalysts for cyclopropanation. Reaction of [Cu(L)Cl₂], [Rh(L)Cl₃] or cis- or trans-[Ru(L)(X)Cl₂] with AgOTf converted the complex to catalyst, which in the case of trans-[Ru(L)(CO)Cl₂] gave enantioselectivities of up to 67% ee for the cis-isomers of styrene cyclopropanes with t-butyl diazoacetate. Comparisons with C₂-analog of copper, rhodium and ruthenium catalysts were made.