N-donor co-ligand-driven zinc coordination polymers based upon a bithiophene dicarboxylate: syntheses, structures, and luminescent properties

<div><p>Three zinc compounds assembled from a bithiophene dicarboxylic acid (H₂DMTDC) and different N-donor co-ligands, [Zn(DMTDC)(bpt)(H₂O)]_n (<b>1</b>), {[Zn(DMTDC)(5,5-dmbpy)]·0.5DMF·1.5H₂O}_n (<b>2</b>), and {[Zn(DMTDC)(1,3-bimb)]·2DMF·H₂O}_n (<b>3</b>) (H₂DMTDC = 3,4-dimethylthieno[2,3-<i>b</i>]thiophene-2,5-dicarboxylic acid, bpt = 4-amino-3,5-bis(4-pyridyl)1,2,4-triazole, 5,5′-dmbpy = 5,5′-dimethyl-2,2′-bipyridyl, 1,3-bimb = 1,3-bis(imidazol-1ylmethyl)benzene), were solvothermally synthesized and characterized. Compounds <b>1</b> and <b>2</b> are 1-D linear and zigzag chains with different supramolecular structures. In <b>1</b>, adjacent chains form zipper-like structures through N–H⋯N interactions. In <b>2</b>, however, chains in adjacent layers are stacked in an unusual unparallel level through C–H⋯O interactions. Compound <b>3</b> features a highly corrugated 2-D (4,4) layer and the layers are penetrated by each other to give 3-D polycatenations. Right- and left-handed helical Zn-bimb chains are arranged alternately within and between the layers, leading to mesomeric property of the whole network. Thermal stability and the decomposed products of all compounds were investigated. Luminescent properties of the ligands and compounds in the solid state at room temperature have also been explored. Moreover, the luminescence intensities of the compounds in different solvents are largely dependent on the solvent.</p></div

Uniting Ruthenium(II) and Platinum(II) Polypyridine Centers in Heteropolymetallic Complexes Giving Strong Two-Photon Absorption

New trinuclear RuPt₂ and heptanuclear RuPt₆ complex salts are prepared by attaching Pt^II 2,2′:6′,2″-terpyridine (tpy) moieties to Ru^II 4,4′:2′,2″:4″,4‴-quaterpyridine (qpy) complexes. Characterization includes single crystal X-ray structures for both polymetallic species. The visible absorption bands are primarily due to Ru^II → qpy metal-to-ligand charge-transfer (MLCT) transitions, according to time-dependent density functional theory (TD-DFT) calculations. These spectra change only slightly on Pt coordination, while the orange-red emission from the complexes shows corresponding small red-shifts, accompanied by decreases in intensity. Cubic molecular nonlinear optical behavior has been assessed by using Z-scan measurements. These reveal relatively high two-photon absorption (2PA) cross sections σ₂, with maximal values of 301 GM at 834 nm (RuPt₂) and 523 GM at 850 nm (RuPt₆) when dissolved in methanol or acetone, respectively. Attaching Pt^II(tpy) moieties triples or quadruples the 2PA activities when compared with the Ru^II-based cores

A Series of Four-Connected Entangled Metal–Organic Frameworks Assembled from Pamoic Acid and Pyridine-Containing Ligands: Interpenetrating, Self-Penetrating, and Supramolecular Isomerism

Five novel compounds, {[Ni(PA)(bpe)(H₂O)₂]·DMF}_<i>n</i> (<b>1</b>), {[Zn(PA)(bpe)]·DMF}_<i>n</i> (<b>2</b>), {[Zn(PA)(bpe)]·2DMF·CH₃OH}_<i>n</i> (<b>3</b>), {[Cd₂(PA)₂(bpe)₂(H₂O)]·3.5H₂O}_<i>n</i> (<b>4</b>), {[Ni₂(PA)₂(bpp)₂(H₂O)₃]·2DMF}_<i>n</i> (<b>5</b>), based on pamoic acid (H₂PA) (bpe = 1,2-bi(4-pyridyl)ethane, bpp = 1,3-bi(4-pyridyl)propane) have been synthesized. In such a system, both the PA^2– anion ligand and dipyridyl ligands act as bipodal linkers, connecting the metal centers in square or tetrahedral geometries into 4-connected topologies with different entangled modes: 3-fold interpenetrating CdSO₄ net (6⁵.8) (<b>1</b>), roto-translational [2 + 2] interpenetrating diamond pseudosupramolecular isomers (<b>2</b> and <b>3</b>), 3-fold interpenetrating (6.7⁴.8)(6⁴.7.8) (<b>4</b>) and (6.8⁵)(6⁴.8²) net with both 2-fold interpenetrating and self-penetrating characters (<b>5</b>), respectively. The formation of unique penetrating frameworks was investigated in detail. Gas adsorption and photoluminescent properties of the compounds have also been explored