Eu-MOFs with 2-(4-carboxyphenyl)imidazo[4,5-f]-1,10-phenanthroline and ditopic carboxylates as coligands: synthesis, structure, high thermostability, and luminescence properties.

Hydrothermal reactions of europium(III) salt with 2-(4-carboxyphenyl)imidazo[4,5-f]-1,10-phenanthroline and dicarboxylic acid as coligands-benzene-1,4-dicarboxylic acid, 4,4'-biphenyldicarboxylic acid, 2,5-dibromoterephthalic acid, and naphthalene-1,4-dicarboxylic acid-lead to four europium fluorescent materials (1-4). Structural analyses reveal that 1-4 have binuclear 3D metal-organic frameworks with different channels, void volumes, and conjugated structures tuned by ditopic carboxylates. There are no latticed and coordinated water molecules occurring in 1-3, while the free water molecules fill in 1D channels of 4. 4' was readily obtained via water removal of 4. Thermal analyses of all compounds show the high thermal stability of the main framework up to 450 °C. Optical studies indicate that 1-4 and 4' show the characteristic red luminescence emission of the Eu(III) ion in the visible regions at room temperature. On the basis of emission spectra, their luminescence lifetimes were determined. In particular, compound 4' shows a longer lifetime (τ = 0.942 ms) and significantly enhanced quantum yield (39%) compared with those of 1 (11%, 0.770 ms), 2 (4%, 0.414 ms), 3 (18%, 0.807 ms), and 4 (26%, 0.858 ms).

A new polymorph of 5,5'-(ethane-1,2-di-yl)bis-(1H-tetra-zole).

The asymmetric unit of the title compound, C(4)H(6)N(8), contains a quarter of the mol-ecule, which possesses a crystallographically imposed centre of symmetry with all non-H atoms situated on a mirror plane. The crystal packing exhibits inter-molecular N-H⋯N hydrogen bonds and π-π stacking inter-actions between the tetra-zole rings of adjacent mol-ecules [centroid-centroid distance = 3.4402 (10) Å].

2-(5-Amino-2H-tetra-zol-2-yl)acetic acid.

In the title mol-ecule, C(3)H(5)N(5)O(2), the tetra-zole ring and carboxyl group form a dihedral angle of 82.25 (14)°. In the crystal, adjacent mol-ecules are linked through O-H⋯N, N-H⋯O and N-H⋯N hydrogen bonds into layers parallel to the bc plane.

Ethane-1,2-diaminium bis-{5-[4-(1H-tetra-zol-5-yl)phen-yl]tetra-zolide} dihydrate.

In the two anions of the title salt, C(2)H(10)N(2) (2+)·2C(8)H(5)N(8) (-)·2H(2)O, the central aromatic rings make dihedral angles of 13.53 (6) and 6.53 (7)° with the deprotonated tetra-zole rings, and 11.39 (6) and 10.41 (9)° with the other tetra-zole groups. In the crystal, the cations, anions and water mol-ecules are linked by an extensive O-H⋯N, N-H⋯O and N-H⋯N hydrogen-bond network into two-dimensional wave-like duplex sheets extending parallel to the bc plane. π-π stacking inter-actions between benzene rings [inter-centroid distances are 3.8482 (4) and 3.9621 (5) Å] and between tetra-zole rings [inter-centroid distances are 3.4350 (4) and 3.7169 (4) Å] further consolidate the crystal structure.

Bis[(1-methyl-1H-tetra-zol-5-yl)sulfan-yl]ethane.

The title compound, C(6)H(10)N(8)S(2), was prepared by the nucleophilic substitution reaction of 5-mercapto-1-methyl-tetra-zole and dichloro-ethane. In the crystal, the mol-ecule possesses an approximate non-crystallographic twofold symmetry axis. The crystal packing is stabilized by weak inter-molecular C-H⋯N and π-π inter-actions [centroid-centroid distances = 3.448 (6), 3.5085 (5) and 3.4591 (2) Å]. The two five-membered rings form a dihedral angle of 1.9 (2)°.

Bis[(1-methyl-1H-tetra-zol-5-yl)sulfan-yl]methane.

The mol-ecule of the title compound, C(5)H(8)N(8)S(2), lies on a twofold rotation axis that relates on 1-methyl-tetra-zolyl group to the other; the five-membered rings are twisted by 53.1 (1)°.