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This paper presents three new lanthanide coordination polymers [Pr2(pim)3(phen)2(H2O)]n·3nH2O (1) (H2pim=pimelic acid; phen=1,10-phenanthroline) and [Ln(Hpim)(pim)(phen)]n·1.5nH2O (Ln=Nd, 2; Er, 3) prepared by the hydrothermal reaction. The structural details of complexes 1, 2 and 3 are reported. In complex 1, the Pr(III) ions are bridged by pim in three modes to form 2D layers. Adjacent layers are assembled by hydrogen bonds and π–π stacking between phen ligands into a 3D network. In complex 2, the Nd(III) ions are connected by pim and Hpim in two modes into 1D chains. Hydrogen bonding and π–π stacking between chains result in a 3D supramolecular structure. Single crystal X-ray diffraction analysis shows that complex 3 is isostructural with complex 2. [Copyright &y& Elsevier]

Reported herein are the hydrothermal synthesis and crystal structures of four lanthanide coordination polymers with nitrilotriacetic acid (H3NTA) [Ln(NTA)(H2O)]n (Ln=La, 1; Pr, 2; Nd, 3; Eu, 4). Despite similar syntheses, compounds 1 to 4 show transformation in coordination mode of NTA and coordination number of Ln3+ duo to lanthanide contraction. The Ln(III) ions in 1 and 2 are nine-coordinated and connected through octadentate bridging ligands (NTA) to form a three-dimensional network. The Ln(III) ions in 3 and 4 are eight-coordinated and bridged by heptadentate bridging ligands (NTA) to form an extended two-dimensional layer structure, which further construct a three-dimensional supramolecular structure via coordination bond and three-centered hydrogen bonding between adjacent layers. [Copyright &y& Elsevier]

[Eu(ABA)(phen)2(H2O)3](ClO4)3·3phen·4.5H2O (1) and [Eu(Val)(phen)2(H2O)3](ClO4)3·3phen·2H2O (2) are two new europium complexes with amino acids and 1,10-phenanthroline (phen=1,10-phenanthroline, ABA=α-amino butyl acid, Val=l-valine). Their crystal structures were measured by X-ray crystallography. Europium atoms in both complexes are nine-coordinated with bidentate 1,10-phenanthroline and carboxylate anion of amino acids, and water molecules. In the solid state, 1 and 2 have a structure involving aromatic stacking of the coordinated and non-coordinated 1,10-phenanthroline and the oxygen atoms of non-coordinated perchlorate anions being H-bond acceptors connect [Eu(ABA)(phen)2(H2O)3]3+·3phen·4.5H2O or [Eu(Val)(phen)2(H2O)3]3+·3phen·2H2O in their structures. In their interactions, several C–H⋯O bonds play an important role. Owing to their different amino acid ligands and the number of lattice water molecules, there is some difference in their hydrogen bond patterns in 1 and 2. The side chain of l-valine is involved in the formation of C–H⋯O bonds. Hydrogen bond and π–π interactions determine the supramolecular formation of three-dimensional net works of both complexes. [Copyright &y& Elsevier]

A new fluorescent sensor 6-(2,3-dihydroxyphenyl)-5,6-dihydrobenzoimidazo[1,2-c] quinazoline (H 2 L) and the Zn(II) complex [Zn 2 L 1 2 ]∙C 2 H 5 OH (H 2 L 1 = 3-{[2-(1 H -benzoimidazol-2-yl)-phenylimino]-methyl}-benzene-1,2-diol) ( 1 ) were synthesized and characterized by single-crystal X-ray diffraction. H 2 L can be used to recognize Cu 2+ in aqueous media as an on–off fluorescent sensor, forming the Cu(II) Schiff-base complex (CuL 1 ). Furthermore, CuL 1 can serve as an off–on fluorescent sensor to detect histidine (His) via the ligand displacement approach. The sequential detection of Cu(II) and histidine shows on–off–on phenomenon. The crystal structure of the dinuclear Zn(II) complex indicates that the coordination of H 2 L with Zn(II) promotes C N bond breakage, resulting in the quinazoline ring-opening of H 2 L to form the Zn(II) Schiff-base complex ( 1 ). The experimental results proved that H + can also assist the ring-opening of H 2 L to form a Schiff base, H 2 L 1 . H 2 L is stable in neutral and weak basic solutions. This is further confirmed by the theoretical calculations. The cell imaging studies indicated that H 2 L and CuL 1 can be used to detect the intracellular Cu 2+ ion and His under physiological conditions, respectively. CuL 1 can also be used to determine His in urine. [ABSTRACT FROM AUTHOR]

A chemosensor 3-[(2-hydroxybenzylidene)-amino]-1H-pyridin-2-one (HL) for multi-ions was synthesized and characterized by single-crystal X-ray diffraction. HL is a turn-on fluorescence chemosensor for Al 3+ , F − , and CN − ions in DMSO. F − and CN − anions could be further distinguished by the ratiometric absorption spectrometry method. Job plot and 1 H NMR data showed that the binding stoichiometries of HL with Al 3+ , F − , or CN − all were 1:1. Further observations of 1 H NMR titration and ESI-MS showed that the possible fluorescent species of Al 3+ with HL was [AlL(OH)(DMSO) 2 ] + in DMSO. The spectroscopic observations of the Al(III) complex showed that the two oxygen atoms and one imine nitrogen atom of HL were coordinated to the Al(III) ion. While the crystal structure of the Ni(II)-L complex confirmed the tridentate coordination mode of HL in the complexes. The experimental results revealed that HL and F − ion formed hydrogen bond in DMSO, while CN − attacked the carbon atom at –C N of HL to undergo a nucleophilic addition. The theoretical calculations confirmed that HL showed very weak fluorescence because of the excited-state intramolecular proton transfer (ESIPT). The turn-on sensing of HL to Al 3+ , F − , and CN − ions arose from the inhibition of ESIPT. MTT tests showed that HL was low toxic to cells. Also, HL could probe intracellular Al 3+ and F − ions by bioimaging. [ABSTRACT FROM AUTHOR]

A quinazoline-based fluorescence chemosensor, 6-phenol-2-yl-(5,6-dihydrobenzimidazo[1,2-c])quinazoline (HL), for highly selective recognition of Cu(ii) in aqueous media was synthesized. The detection limit was of the order of 10−6 M. The crystal structures of the Cu(ii) and Cd(ii) complexes showed that HL changed to a Schiff base when it reacts with metal salts and that the metal ions coordinate with two nitrogen atoms and one hydroxyl oxygen atom from the Schiff base. The theoretical calculations at B3LYP-SCRF/6-31G(d) confirmed that it is the Cu(ii) ion that assisted the ring-opening of the quinazoline derivative, forming a Cu(ii) Schiff base complex during the detection. LMCT leads to the disappearance of fluorescence. A cell imaging study indicated that HL could be used to detect the intracellular Cu2+ ion. [ABSTRACT FROM AUTHOR]

Three novel isostructural lanthanide(III) coordinationpolymers(LnCPs), {[Ln3(bidc)4(phen)2(NO3)]·2H2O}n(Ln= Gd (1), Eu (2), Tb (3); H2bidc = benzimidazole-5,6-dicarboxylic acid, and phen = 1,10-phenanthroline),were synthesized via hydrothermal reaction and characterized. Thecomplexes crystallize in the chiral space group P212121. They possess 1D structuresbased on lanthanide trinuclear clusters containing Ln(1)O9, Ln(2)O6N2, and Ln(3)O6N2polyhedra by bidc linkers, and phen and nitrate act as terminalligands. The bidc and phen ligands provide efficient energy transferfor the sensitization of Eu(III) and Tb(III) complexes. The complexes 2and 3emit red and green light, respectively.Lifetimes and quantum yields of luminescence are 0.86 ms and 13.20%for 2and 0.32 ms and 2.08% for 3. Tuningof white-light emission by adjusting the doping concentration of Eu(III)and Tb(III) ions in the Gd(III) complex was achieved. [ABSTRACT FROM AUTHOR]