Five new coordination polymers based on Ln³⁺ and 2,5-diiodoterephthalates (2,5-I-bdc)— {[La₂(2,5-I-bdc)₃(DMF)₄]}·2DMF (1) and {[Ln₂(2,5-I-bdc)₃(DMF)₄]} (Ln = La (2), Nd (3), Sm (4) and Eu (5))—were prepared and characterized by single crystal and powder X-ray diffractometry. Luminescent behavior was examined (the highest quantum yield is 4.5%); thermal stability was examined using thermogravimetric analysis.

Reactions between Zn(II) nitrate, pentaiodobenzoic acid (HPIBA) and different pyridines in dimethylformamide (DMF) result in the formation of the heteroleptic neutral complexes [Zn(3,5-MePy)₂PIBA₂] (1) and [Zn(DMF)₃(NO₃)PIBA] (2). Both compounds were isolated in pure form, as shown by the PXRD data. The features of specific non-covalent interactions involving halogen atoms (halogen bonding) were examined by means of DFT calculations (QTAIM analysis and the estimation of corresponding energies).

Coordination polymers [Gd₂(5-iip)₃(DMF)₄]·0.4DMF (1) and [Dy₂(5-iip)₃DMF₂]·0.33DMF (2) (5-iip²⁻—5-iodoisophthalate) feature two different structural types, as follows from X-ray diffractometry data. We prepared and characterized an extended series of corresponding heterometallic complexes of the composition [Gd_xDy_2−x(5-iip)₃DMF₂]·0.33DMF and [Eu_xDy_2−x(5-iip)₃DMF₂]·0.33DMF, where x = 0.2, 0.4…1.8, and examined the changes of their luminescent properties induced by variations of metal composition, finding the promising white emission sources with high light purity.

Structural data are obtained for a coordination polymer of Cd(II) with 2-iodoterephthalic acid as a by-product of the synthesis of a heterometallic Cd/Zn MOF. The composition and structure of the [Cd(2-I-bdcH)₂] (1) compound are determined by XRD after optimizing the synthesis technique and obtaining good-quality single crystals.