Jednačak, Tomislav; Đilović, Ivica; Korica, Milenko; Balić, Tomislav; Novak, Jurica (2026) Macrocyclic N4O4 - donor Schiff bases: the effect of an aldehyde precursor on structure, conformation and properties. Journal of Molecular Structure, 1364 . ISSN 0022-2860
![[img]](http://fulir.irb.hr/style/images/fileicons/application_pdf.png) |
PDF
- Accepted Version
- article
Restricted to Closed Access until 6 March 2028. Available under License Creative Commons Attribution Non-commercial No Derivatives. Download (1MB) | Request a personal copy from author |
Abstract
Porous imine-based macrocycles are promising materials for the detection and removal of toxic chemical species. These compounds can be rationally designed by utilizing different amine and aldehyde precursors for a specific application. In this work, we used dialdehyde precursors with different aliphatic chain lengths and p-phenylenediamine for the preparation of 36-, 40-, and 42-membered N4O4-donor macrocyclic Schiff base analogues (pDo4 = 1,6,19,24-tetraaza-2,5:8,9:16,17:20,23:26,27:34,35-hexabenzo-10,15,28,333-tetraoxa-cyclohexatriakonta-1,6,19,24-tetraen, pDo6 = 1,6,21,26-tetraaza-2,5:8,9:18,19:22,25:28,29:38,39-hexabenzo-10,17,30,37-tetraoxa-cyclotetraconta-1,6,21,26-tetraen, pDo7 = 1,6,22,27-tetraaza-2,5:8,9:19,20:23,26:29,30:40,41-hexabenzo-10,18,31,39-tetraoxa-cyclodotetraconta-1,6,20,25-tetraen). The prepared macrocycles were structurally characterized using experimental (NMR, IR, TG) and theoretical (MMFF, DFT) methods. The crystal structure of pDo7 was determined by single-crystal X-ray diffraction. The pDo7 molecule is N4O4– donor macrocyclic Schiff base with 42 non-hydrogen atoms in the macrocyclic ring that crystallizes as a benzene solvate. It is planar and rectangular in shape and connected by weak C−H‧‧‧π and C−H‧‧‧C interactions forming a sheet-like supramolecular motif. The compound can be regarded as a shape-persistent porous material, with pores occupied by solvent molecules in the solid state. NMR studies in solution pointed towards higher flexibility of larger macrocycles, allowing additional interactions with the solvent. Characteristic peaks in the solid-state NMR spectra indicated similar orientations of all imine nitrogens, which is in line with the structures in solution. The conformational landscapes of pDo4 and pDo6 were systematically explored using MMFF-preoptimized structures followed by DFT calculations in the gas phase. While pDo4 exhibits a relatively compact ensemble of low-energy conformers with subtle structural variations, pDo6 shows a broader and more heterogeneous conformational distribution, reflecting its enhanced flexibility and longer linker architecture.
| Item Type: | Article | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Uncontrolled Keywords: | macrocyclic Schiff bases; synthesis; structure characterization; conformational analysis; force field; DFT optimization | ||||||||||||
| Subjects: | NATURAL SCIENCES NATURAL SCIENCES > Chemistry |
||||||||||||
| Divisions: | Center for Informatics and Computing | ||||||||||||
| Projects: |
|
||||||||||||
| Depositing User: | Jurica Novak | ||||||||||||
| Date Deposited: | 18 Mar 2026 11:59 | ||||||||||||
| URI: | http://fulir.irb.hr/id/eprint/11363 | ||||||||||||
| DOI: | 10.1016/j.molstruc.2026.145872 |
Actions (login required)
 |
View Item |
Altmetric
Altmetric
