Publications by authors named "Jianqiu Ma"

Dielectric metasurfaces, which are capable of manipulating incident light, have been a novel branch of flat optics. This modulation ability is realized by nanostructures with space-variant geometrical parameters such as height and diameter. Therefore, accurate profile measurement of metasurfaces is of great importance.

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Most bacteria possess only one heme-degrading enzyme for obtaining iron, however few bacteria such as Pseudomonas aeruginosa express two, namely PhuS and HemO. While HemO is a well-known heme oxygenase, previously we discovered that PhuS also possesses heme degradation activity and generates verdoheme, an intermediate of heme breakdown. To understand the coexistence of these two enzymes, using the DFT calculation we reveal that PhuS effectively enhances heme degradation through its participation in heme hydroxylation, the rate limiting reaction.

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A new discrete supramolecular metallacycle functionalized with an alkynylplatinum(II) bzimpy moiety was successfully prepared via coordination-driven self-assembly, and it displayed a reversible color change in the solid state between yellow and red, triggered by CH2Cl2 vapor or mechanical grinding. Notably, unlike many known vapochromic systems, the obtained vapochromic metallacycle exhibits ultra-stability, with the red color remaining unchanged in air for several months at room temperature or even under vacuum for >1 week. Further investigation revealed that the chair conformation of the metallacyclic scaffold, which was thought to prevent intermolecular steric repulsion between the alkyl chain and triethylphosphine, favored close molecular stacking through intermolecular Pt···Pt and π-π stacking interactions, thus allowing such vapochromic behavior with ultra-stability.

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In recent past years, investigation of hierarchical self-assembly for constructing artificial functional materials has attracted considerable attention. Discrete metallacycles based on coordination bonds have proven to be valid scaffolds to fabricate various supramolecular polymers or smart soft matter through hierarchical self-assembly. Here, we present the first example of the hierarchical self-assembly of discrete metallacycles by taking advantage of the positive charges of the organoplatinum(II) metallacycle skeleton through multiple electrostatic interactions.

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A new family of 120° carbazole-based dendritic donors D1-D3 have been successfully designed and synthesized, from which a series of novel supramolecular carbazole-based metallodendrimers with well-defined shapes and sizes were successfully prepared by [2+2] and [3+3] coordination-driven self-assembly. The structures of newly designed rhomboidal and hexagonal metallodendrimers were characterized by multinuclear NMR ((1) H and (31) P) spectroscopy, ESI-TOF mass spectrometry, FTIR spectroscopy, and the PM6 semiempirical molecular orbital method. The fluorescence emission behavior of ligands D1-D3, rhomboidal metallodendrimers R1-R3, and hexagonal metallodendrimers H1-H3 in mixtures of dichloromethane and n-hexane with different n-hexane fractions were investigated.

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The synthesis of discrete multirotaxanes with well-defined structures remains a great challenge. Herein, we present the successful construction of diverse discrete multirotaxanes with well-defined supramolecular metallacycles as cores by a modular approach. Moreover, these novel multirotaxanes featured a stimuli-responsive property that enabled the introduction and removal of the bromide anion by taking advantage of dynamic nature of the supramolecular metallacycle scaffold.

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Preparation and characterization of two new triptycene based polytopic Pt(II) organometallic complexes are being reported. These complexes have three trans-bromobis(trialkylphosphine)platinum(II) units directly attached to the central triptycene unit. These organoplatinum complexes were converted to the corresponding nitrate salts for subsequent use in self-assembly reactions.

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