Two new tetranuclear cationic metalla-bowls 4 and 5 were self-assembled from a bis-pyridine amide ligand (H(2)L) (1) and arene-ruthenium acceptors, [(Ru(2)(μ-η(4)-C(2)O(4))(η(6)-p-cymene)(2)](O(3)SCF(3))(2) (2) and [Ru(2)(dhnd)(η(6)-p-cymene)(2)](O(3)SCF(3))(2) (dhnd = 6,11-dihydroxy-5,12-naphthacenedionato) (3), respectively. The metalla-bowls were characterized by multinuclear NMR, ESI-MS, UV-Vis spectroscopy, and single crystal X-ray diffraction study of 4. The crystal structure of 4 reveals unambiguous proof for the molecular shape of the metalla-bowl and the encapsulation of one triflate anion in the cavity through hydrogen bonding. The metalla-bowl 5 has been evaluated for anion binding studies by use of amide ligand as a hydrogen bond donor and arene-Ru acceptor as a signalling unit. UV-Vis titration studies showed that 5 selectively binds with multi-carboxylate anions such as oxalate, tartrate and citrate in a 1 : 1 fashion with high binding constants of 4.0-5.5 × 10(4) M(-1). Furthermore, the addition of multi-carboxylate anions into a solution of 5 gave rise to a large enhancement of fluorescence intensity attributable to the blocking of a photo-induced electron transfer process from the arene-ruthenium moiety to the amidic donor in 5. However, the fluorescence intensity almost remains unchanged upon addition of other anions including F(-), Cl(-), PF(6)(-), MeCOO(-), NO(3)(-) and PhCOO(-), as identically seen in the UV-Vis titration experiments, pointing to the high selectivity of 5 for the sensing of multi-carboxylate anions.
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http://dx.doi.org/10.1039/c1dt11612f | DOI Listing |
Dalton Trans
October 2013
College of Chemistry and Molecular Engineering, Zhengzhou University, Zhengzhou 450001, Henan, P. R. China.
2-Carboxylphenyl, 3-carboxylphenyl and 4-carboxylphenyl groups were introduced into the 2-position of imidazole-4,5-dicarboxylate system, respectively, obtaining three multi-functional ligands 2-(2-carboxylphenyl)-1H-imidazole-4,5-dicarboxylic acid (o-CPhH4IDC), 2-(3-carboxylphenyl)-1H-imidazole-4,5-dicarboxylic acid (m-CPhH4IDC) and 2-(4-carboxylphenyl)-1H-imidazole-4,5-dicarboxylic acid (p-CPhH4IDC). Then the three organic ligands are employed to react with Sr(II) and Cd(II) ions. Subsequently, five 3D or 2D polymers, [Sr(o-CPhH2IDC)]n (1), [Sr3(m-CPhHIDC)2(H2O)3]n (2), [Sr(p-CPhH2IDC)(H2O)]n (3), [Cd(o-CPhH2IDC)(H2O)2]n (4) and {[Cd3(m-CPhHIDC)2(H2O)8]·2H2O}n (5), have been hydro(solvo)thermally synthesized and structurally characterized.
View Article and Find Full Text PDFDalton Trans
July 2013
College of Chemistry and Chemical Engineering, Luoyang Normal University, Luoyang, 471022, P. R. China.
Reactions of lanthanide(III) nitrates with multi-donor carboxylate ligand in the presence of oxalate anion afforded four new lanthanide coordination polymers with three dimensional (3D) frameworks, namely, {[Ln2(DPPA)2(μ2-C2O4)(H2O)2]·2H2O}n (Ln = Nd (1), Sm (2)) and [Ln2(HDPPA)2(DPPA)2]n (Ln = Tb (3), Yb (4)), (H3DPPA = 3-(4-hydroxyl pyridinium-1-yl) phthalic acid and H2C2O4 = oxalic acid). Compounds 1 and 2 are isostructural and isomorphous, featuring oxalate pillared binodal (4,5)-connected porous 3D framework with intersected 1D channels, in which the coordinated and lattice waters are accommodated. The complexes 3 and 4 are also isostructural, but featuring a (4,6)-connected 3D network based on a rectangular window composed of {Ln(HDPPA)}(+) extended anion chains, further interlinked by DPPA.
View Article and Find Full Text PDFDalton Trans
January 2012
Department of Chemistry, University of Ulsan, Ulsan, 680-749, Republic of Korea.
Two new tetranuclear cationic metalla-bowls 4 and 5 were self-assembled from a bis-pyridine amide ligand (H(2)L) (1) and arene-ruthenium acceptors, [(Ru(2)(μ-η(4)-C(2)O(4))(η(6)-p-cymene)(2)](O(3)SCF(3))(2) (2) and [Ru(2)(dhnd)(η(6)-p-cymene)(2)](O(3)SCF(3))(2) (dhnd = 6,11-dihydroxy-5,12-naphthacenedionato) (3), respectively. The metalla-bowls were characterized by multinuclear NMR, ESI-MS, UV-Vis spectroscopy, and single crystal X-ray diffraction study of 4. The crystal structure of 4 reveals unambiguous proof for the molecular shape of the metalla-bowl and the encapsulation of one triflate anion in the cavity through hydrogen bonding.
View Article and Find Full Text PDFChemistry
July 2011
Department of Chemistry, University of Ulsan, Ulsan 680-749, Republic of Korea.
Novel arene-ruthenium [2+2] metalla-rectangles 4 and 5 have been synthesized by self-assembly using dipyridyl amide ligand 3 and arene-ruthenium acceptors (arene: benzoquinone (1), naphthacenedione (2)) and characterized by NMR spectroscopy and ESI-MS. The solid-state structure of 5 was determined by X-ray diffraction and shows encapsulated diethyl ether molecule in the rectangular cavity of 5. The luminescent 5 was further used for anion sensing with the amidic linkage serving as a hydrogen-bond donor site for anions and the ruthenium moiety serving as a signaling unit.
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