H2PO4–- and Solvent-Induced Polymorphism of an Amide-Functionalized [Pt(N^C^N)Cl] Complex

Solid-State Structural Transformation and Photoluminescence Properties of Supramolecular Coordination Compounds

The combination of strong coordination bonds and hydrogen bonding interactions were used to generate a series of supramolecular coordination materials (SCMs), which was achieved by reacting a bis-pyridyl amide ligand, namely N-(4-pyridyl)nicotinamide (4PNA) with copper(II), zinc(II), and cadmium(II) benzoates. The SCMs were structurally characterized using X-ray diffraction and the key intermolecular interactions were identified via Hirshfeld surface analysis. The role of solvent molecules on the supramolecular architecture was analyzed by synthesizing the SCMs in different solvents/solvent mixtures. A solvent-mediated solid-state structural transformation was observed in copper(II) SCMs and we were able to isolate the intermediate form of the crystal-to-crystal transformation process. The luminescence experiments revealed that complexation enhanced the fluorescence properties of 4PNA in the zinc(II) and cadmium(II) SCMs, but a reverse phenomenon was observed in the copper(II) SCMs. This work demonstrated the tuning of supramolecular assembly in coordination compounds as a function of solvents for generating SCMs with diverse properties.

Reversible stimuli-responsive chromism of a cyclometallated platinum(II) complex

We report the reversible chromism and luminescence of a cyclometalated platinum(ii) complex that forms dimers, with close PtPt interactions that can be modulated by solvent and temperature. The precise reversible control may be exploited in future stimuli-responsive chemosensing or optoelectronic devices.

Macrocyclic Metal Complexes Bearing Rigid Polyaromatic Ligands: Synthesis and Catalytic Activity

We synthesised palladium and platinum complexes possessing cyclic and acyclic pincer-type polyaromatic ligands and investigated their structural effect on the catalysis. The pincer-type bis(6-arylpyridin-2-yl)benzene skeleton was constructed via Kröhnke pyridine synthesis under transition metal-free conditions on gram-scale quantity. Ligand structure significantly influenced catalytic activity toward the platinum-catalysed hydrosilylation of diphenyl acetylenes, despite the ligand-independence of the conformations and electronic properties of these complexes.

Stabilizing Metastable Polymorphs of Metal-Organic Frameworks via Encapsulation of Graphene Oxide and Mechanistic Studies

Polymorphic transition from a metastable phase to a stable phase often occurs in metal-organic frameworks (MOFs) under the action of external stimuli. However, these transitions sometimes result in deteriorating their special performances and can even lead to serious safety problems. Therefore, developing a simple and efficient strategy for enhancing the stabilities of metastable MOF polymorphs is very imperative and meaningful. Herein, we propose a simple graphene oxide (GO)-encapsulating strategy for improving the stabilities of metastable MOF polymorphs. To illustrate this strategy, we designed and synthesized two polymorphic MOFs [MOF(ATA-a) and MOF(ATA-b)] as examples, which are based on energetic 5-amino-1 H-tetrazole as ligands. Single-crystal X-ray diffraction showed that these two polymorphs have a same chemical composition [Zn₂(ATA)₃(ATA)_2/2] _n, but different space groups, space systems, and different stacking modes of the neighboring ligands. As expected, the metastable polymorph [MOF(ATA-a)] underwent a complete polymorphic transition at room temperature to form its stable polymorph [MOF(ATA-b)]. Using the proposed strategy, we successfully encapsulated a small amount of GO in the metastable polymorph [GO⊂MOF(ATA-a)]. The resultant composite exhibited better chemical stability, extremely higher thermal stability, and larger Brunauer-Emmett-Teller surface area compared to both its precursor and the physically mixed analogue. Remarkably, its onset decomposition temperature ( T_d) was as high as 377.4 °C, which is even higher than that of 1,3,5-triamino-2,4,6-trinitrobenzene ( T_d = 321 °C), making it a potential heat-resistant explosive. The mechanism of stabilization was investigated in detail using various analytical techniques. This work may not only provide new insights into the stabilization of functional MOF polymorphs but also open up a new field for the application of GO.

Synthesis, crystal structure, photophysical property and metal ion-binding behavior of a cyclometalated platinum(ii) terpyridylacetylide with efficient π-conjugation degree

The “Donor–Phosphore–Receptor” platform as a novel building block for formation of heterotrinuclear transition metal complexes.