Two Cu-based cluster coordination polymers constructed from two thioether tripod tricarboxylic acid ligands: Synthesis, crystal structure and fluorescence sensing

Synthesis, crystal structure, and topology of a polycatenated bismuth coordination polymer

Solvothermal reaction of Bi(NO3)3·5H2O with the flexible ligand 1,3,5-tris[4-(carboxyphenyl)oxamethyl]-2,4,6-trimethylbenzene (H3TBTC) in methanol at 120 °C for 1 h led to the formation of a novel coordination polymer (CP) with the composition of Bi(TBTC). The structure of the microcrystalline material was determined through three-dimensional electron diffraction (3DED) measurements and phase purity was confirmed by a Pawley refinement, elemental analysis, and thermal analysis. The compound crystallizes in the triclinic space group P 1 ‾ $P\overline{1}$ with one Bi3+ cation and one TBTC3− trianion in the asymmetric unit. Edge-sharing of BiO7 polyhedra leads to the formation of dinuclear Bi2O12 units, which through coordination to six TBTC3− ions form a layered two-periodic structure. Upon heating the material in air, the unit cell volume contracts by 9%, which is attributed to a shift in the inter-layer arrangement and to the flexibility of the building units of the structure. The compound starts to decompose at ∼300 °C. Topological analysis revealed layers consisting of 3-c and 6-c nodes, consistent with the two-periodic kgd net – the dual of the Kagome net (kgm). However, due to the non-planar nature of the Bi(TBTC) layers, adjacent layers are interlaced by polycatenation.

Polytorsional-amide/carboxylates-directed Cd(ii) coordination polymers exhibiting multi-functional sensing behaviors

By rational assembly of polytorsional-amide [N,N′-bis(4-methylenepyridin-4-yl)-1,4-naphthalene dicarboxamide (L)] and polytorsional-carboxylates [H₂ADI = adipic acid, H₂PIM = pimelic acid, H₂SUB = suberic acid], three new Cd-based coordination polymers (CPs) C₃₀H₃₀CdN₄O₇ (1), C₃₁H₃₂CdN₄O₇ (2) and C_31.03H_30.55CdCl_0.24N₄O_5.52 (3) were successfully synthesized. CPs 1–2 and 3 are 2D networks and a 3D framework, which all display 3,5-connected topologies with different structural details. The effects of carboxylates with different carbon chains on the structure of the complexes were studied. Fluorescence experiments show that CPs 1–3 have good multi-functional sensing ability for metal cations (Fe³⁺), anions (MnO₄⁻, CrO₄²⁻, Cr₂O₇²⁻) and organochlorine pesticides (2,6-dichloro-4-nitroamine) with good anti-interference and recyclable characteristics. The possible sensing mechanism is also investigated in detail.

Three (3,5)-connected Cd(ii) coordination polymers induced by polytorsional-amide/carboxylates exhibiting controllable multifunctional fluorescent sensing activities.