1
|
Tzeli D, Petsalakis ID, Theodorakopoulos G, Rahman FU, Yu Y, Rebek J. The role of electric field, peripheral chains, and magnetic effects on significant 1H upfield shifts of the encapsulated molecules in chalcogen-bonded capsules. Phys Chem Chem Phys 2021; 23:19647-19658. [PMID: 34524297 DOI: 10.1039/d1cp02277f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The chalcogen-bonded homo-cavitand and hetero-cavitand AY+AY' capsules (Y, Y' = Se, Te), as well as their encapsulated complexes with one or two guest molecules have been studied theoretically via density functional theory (DFT), while the 1H NMR spectra of the homo-cavitand encapsulated complexes (in ASe+ASe) have been measured experimentally. There is excellent agreement between theoretical and experimental spectra. In all cases, we found significant 1H upfield shifts which are more intense in the ASe+ASe cage compared to the ATe+ATe and ASe+ATe cages. The non-uniform electron distribution which gives rise to an inherent electric field and a non-zero electric dipole moment of the encapsulated complexes, the induced electric field effects, the magnetic anisotropy which is enhanced due to the polarizability of chalcogen atoms, and the peripheral chains, which are responsible for the solubility of the cages, increase the upfield shifts of 1H of the encapsulated molecules; the peripheral chains lead to an increase of the upfield shifts by up to 1.8 ppm for H of the rim and up to 1.2 ppm for the terminal H in the interior of the cage. Hence, substantial 1H upfield chemical shifts of the guests in these capsules are consequences of (i) the enhanced aromaticity of the walls of the capsules due to the polarizability of chalcogen atoms, (ii) the induced and inherent electric field effects, and (iii) the peripheral chains.
Collapse
Affiliation(s)
- Demeter Tzeli
- Laboratory of Physical Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis Zografou, Athens 157 71, Greece. .,Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vassileos Constantinou Ave., Athens 116 35, Greece.
| | - Ioannis D Petsalakis
- Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vassileos Constantinou Ave., Athens 116 35, Greece.
| | - Giannoula Theodorakopoulos
- Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vassileos Constantinou Ave., Athens 116 35, Greece.
| | - Faiz-Ur Rahman
- Inner Mongolia Mongolia University Research Center for Glycochemistry of Characteristic Medicinal Resources, Department of Chemistry and Chemical Engineering, Inner Mongolia University, Hohhot, China.,Center for Supramolecular Chemistry and Catalysis and Department of Chemistry, Shanghai University, 99 Shang-Da Road, Shanghai 200444, P. R. China
| | - Yang Yu
- Center for Supramolecular Chemistry and Catalysis and Department of Chemistry, Shanghai University, 99 Shang-Da Road, Shanghai 200444, P. R. China
| | - Julius Rebek
- Center for Supramolecular Chemistry and Catalysis and Department of Chemistry, Shanghai University, 99 Shang-Da Road, Shanghai 200444, P. R. China.,Skaggs Institute for Chemical Biology and Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, USA
| |
Collapse
|
2
|
Chalcogen S∙∙∙S Bonding in Supramolecular Assemblies of Cadmium(II) Coordination Polymers with Pyridine-Based Ligands. CRYSTALS 2021. [DOI: 10.3390/cryst11060697] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Two cadmium(II) coordination polymers, with thiocyanate and pyridine-based ligands e.g., 3-acetamidopyridine (3-Acpy) and niazid (nicotinic acid hydrazide, nia), namely one-dimensional {[Cd(SCN)2(3-Acpy)]}n (1) and two-dimensional {[Cd(SCN)2(nia)]}n (2), are prepared in the mixture of water and ethanol. The adjacent cadmium(II) ions in 1 are bridged by two N,S-thiocyanate ions and an N,O-bridging 3-Acpy molecule, forming infinite one-dimensional polymeric chains, which are assembled by the intermolecular N–H∙∙∙S hydrogen bonds in one direction and by the intermolecular S∙∙∙S chalcogen bonds in another direction. Within the coordination network of 2, the adjacent cadmium(II) ions are bridged by N,S-thiocyanate ions in one direction and by N,O,N’-chelating and bridging nia molecules in another direction. The coordination networks of 2 are assembled by the intermolecular N–H∙∙∙S and N–H∙∙∙N hydrogen bonds and S∙∙∙S chalcogen bonds. Being the only supramolecular interactions responsible for assembling the polymer chains of 1 in the particular direction, the chalcogen S∙∙∙S bonds are more significant in the structure of 1, whilst the chalcogen S∙∙∙S bonds which act in cooperation with the N–H∙∙∙S and N–H∙∙∙N hydrogen bonds are of less significance in the structure of 2.
Collapse
|