Yun-Hua Li

Syntheses, structures and photoluminescent properties of a series of Ag(I) coordination architectures based on 2,4-diamino-6-methyl-1,3,5-triazine and dicarboxylates: from a 0D discrete molecule to a 3D infinite network

Five mixed-ligand Ag(I) coordination complexes (CCs), namely, [Ag2(dmt)2(suc)·H2O]n (1), [Ag2(dmt)2(suc)(H2O)·0.5H2O] (2), [Ag2(dmt)2(glu)]n (3), [Ag2(dmt)2(adip)]n (4), and [Ag2(dmt)2(tpa)]n (5) (dmt = 2,4-diamino-6-methyl-1,3,5-triazine, H2suc = succinic acid, H2glu = glutaric acid, H2adip = adipic acid, H2tpa = terephthalic acid), have been synthesized through a one-pot ultrasonic reaction of AgNO3, dmt and different dicarboxylates and characterized by elemental analysis, IR spectroscopy, and X-ray single-crystal diffraction. Complexes 1 and 2 formed in different solvent systems (methanol/acetonitrile for 1 and methanol/ethanol for 2) exhibit a two-dimensional (2D) sheet and a zero-dimensional (0D) tetranuclear motif, respectively. Different solvent systems influence the coordination modes (μ2-N,N′ for 1 and μ1-N for 2) of dmt and the conformations (anti for 1 and gauche for 2) of the suc anion; as a result, two diverse structures are produced. Complex 3 is a one-dimensional (1D) chain structure running along the a axis constructed from the [Ag2(μ1-dmt)2] subunit and the gauche–gauche μ5-η1:η1:η1:η2 glu ligand. Similarly, complex 4 is also a 1D chain structure, but the adip ligand adopts an anti–anti–anti conformation to link the [Ag2(μ1-dmt)2] subunit to complete the 1D chain. Complex 5 is a complicated 3D framework built from a tetrahedral Ag(I) center, a quadridentate tpa and an angular bidentate dmt ligand which can be simplified as a new (2,4,4)-connected 3-nodal net with the Schlafli symbol of {4.84.12}2{42.82.102}{8}2. The results show that the dicarboxylate and the solvent system play crucial roles in the formation of the resulting structures. Additionally, results about thermogravimetric curves and photoluminescence spectra were discussed.

Probing hydrogen bond energies by mass spectrometry.

Mass spectrometry with desorption electrospray ionization (DESI) is demonstrated to be useful for probing the strength of hydrogen bonding, exemplified by various complexes of benzothiazoles and carboxylic acids in the solid state. Efficiencies for fragmentation of the complexes, quantified by collision-induced dissociation (CID) technology, correspond well with energies of the hydrogen bonds of O-H···N and N-H···O bridging each pair of benzothiazole and carboxylic acid. Linear correlations (with correlation factors of 0.8953 and 0.9928) have been established for the calibration curves of normalized collision energy at 100% fragmentation rate vs the length between donor and acceptor (in the hydrogen bond of O-H···N) as well as the slope of the fragmentation efficiency curve vs the average length difference between O-H···N and N-H···O in the complex. The mechanism responsible for determination of the hydrogen bonds is proposed on the basis of the experiments starting from the mixtures of the complexes as well as labeling with deuterium. As a complement of previously available methods (e.g., X-ray diffraction analysis), expectably, the proposed mass spectrometric method seems to be versatile for probing hydrogen bond energies.

CCDC 827639: Experimental Crystal Structure Determination

Related Article: Di Sun, Yun-Hua Li, Hong-Jun Hao, Fu-Jing Liu, Yi-Mei Wen, Rong-Bin Huang, Lan-Sun Zheng|2011|Cryst.Growth Des.|11|3323|doi:10.1021/cg2006953

CCDC 823092: Experimental Crystal Structure Determination

Related Article: Di Sun, Fu-Jing Liu, Hong-Jun Hao, Yun-Hua Li, Na Zhang, Rong-Bin Huang, Lan-Sun Zheng|2011|CrystEngComm|13|5661|doi:10.1039/c1ce05622k

CCDC 823094: Experimental Crystal Structure Determination

Related Article: Di Sun, Fu-Jing Liu, Hong-Jun Hao, Yun-Hua Li, Na Zhang, Rong-Bin Huang, Lan-Sun Zheng|2011|CrystEngComm|13|5661|doi:10.1039/c1ce05622k