Highly Dynamic and Tunable Behavior of 1D Coordination Polymers Based on the Bispidine Ligand

Abstract

Ligands L1 and L2 have been designed, synthesized, and used to build for the first time bispidine‐based coordination polymers (CPs) in combination with MnII. The novel CPs have been structurally characterized by single‐crystal (SC) and powder X‐ray diffraction (P‐XRD) techniques, showing that they are composed of 1D ribbon‐like chains that adopt various arrangements depending on the trapped solvent species. These materials show highly dynamic behavior as they undergo heterogeneous solid/liquid and solid/vapor multiple solvent exchange processes, comprising crystalline–amorphous–crystalline, selective adsorption and SC‐to‐SC transformations, where major structural reorganization of the 1D ribbons are observed. By tuning inter‐ribbon interactions through expansion of the ligand's accessible surface, the dynamic behavior can be effectively modulated.

Synthesis of Natural Compounds Based on the [3,7]‐Diazabicyclo[3.3.1]nonane (Bispidine) Core

“…Recently, the bispidine scaffold was employed to design a multidentate ligand with the aim to obtain new coordination polymers [73] . In Scheme 42 the example illustrates the bispidinic ligand 188 having two divergent nitrogens in the pyridine rings.…”

Tuneable solvent adsorption and exchange by 1D bispidine-based Mn(ii) coordination polymers via ligand design

“…Crystallization under different solvent-mixture conditions using a three-layers crystallization method (see Experimental Section) yielded monosolvated and bisolvated structures, always containing linear ribbon-like arrays. 11,13,14 In particular, the monosolvated CPs 1•TCM SC , 1•NB SC , 4•TCM SC and 4•NB SC , were fully characterized. Within the same family of monosolvated species, two additional CPs containing DCB were obtained.…”

“…Third, the 1D ribbons pack entrapping a variety of solvents between adjacent ribbons (NB, DCB, oNT, pCT and TCM). Considering the crystallization conditions, 11 it can be said that MeOH and THF have no tendency to be trapped within the CP lattice.…”

“…In an earlier work, the synthesis and characterization of CPs with ligands L1 and L4 were fully described. 11 In particular, PXRD, NMR and Thermogravimetric Analysis (TGA) were used to identify each crystalline phase (in combination with simulated PXRD patterns obtained from SC data); moreover, we studied their thermal stability. Here, we present the data relative to CPs with ligands L2, L3 and L5.…”

“…10 Recently, we reported on the first bispidine-based CPs, obtained by orienting the pyridine N donors of the ligand in a divergent fashion, as in L1 (Scheme 1a), and using Mn(II) ions. 11 SC-XRD analysis revealed the formation of monosolvated 1D CPs characterized by ribbon-like linear arrays made of -[Mn(Cl)2(L1)2]-units, and containing chloroform (TCM), nitrobenzene (NB) or dichlorobenzene (DCB) within their lattice. These materials, either as single crystals or microcrystalline powders, proved to be capable to undergo various type of transformations via solvent exchange and adsorption processes.…”