Molecular tectonics: pyridyl containing thiacalix[4]arene based tectons for the generation of 2- and 3-D silver coordination networks

Abstract

Three new organic tectons (2–4) based on the p-tert-butylthiacalix[4]arene backbone, blocked in the 1,3-alternate conformation, bearing four pyridyl coordinating moieties, have been synthesised and characterised in the solid state. The ligands are positional isomers and differ by the position of the N atom on the pyridyl unit (ortho for 2, meta for 3 and para for 4). Their combination with the Ag+ cation leads, reproducibly, to the formation of 2- and 3-D infinite silver coordination networks. Independent of the nature of the anion, the combination of 2 offering four (N,S) type chelates with the Ag+ cation affords an unprecedented diamond type 3D network. Both 3 and 4, behaving as tetrakis monodentate ligands, lead to the formation of 2-D architectures.

Template Synthesis of Tetrakis-triazolylthiacalix[4]arene in the Cone Conformation and Supramolecular Structure of Its Hexanuclear Complex with Ag(I)

“…[18,19] It appeared of interest to investigate the propensity of compound 2 to form either discrete complexes or infinite networks in the presence of Ag(I) cation.…”

Molecular Tectonics: 1D Tubular Type and 3D Diamond Like Mercury(II) Coordination Polymers Based on Pyridyl Appended p-tert-Butyltetrathiacalix[4]arene

“…However, for both TCA and TMTCA, the presence of bridging S atoms not only leads to an enhancement of the size of the macrocycle cavity but also provides additional coordinating sites. Tetrasubstituted thiacalix[4]arene derivatives bearing cyano, [17][18][19] carboxyl, [20][21][22] pyridyl, [23][24][25][26][27][28] coordinating groups were combined with metal cations for the formation of coordination networks displaying a variety of dimensionalities (1D-3D). In contrast to CA, for these sulfur containing tectons, only the 1,3-alternate conformation has been used.…”

The first study about the relationship between the extractability of thiacalix[4]arene derivatives and the position of the coordination binding sites

“…Recently, Ferlay reported a 1,3-alternate conformation thiacalix[4]arene armed with four pyridyl (ortho), complexed with Ag + cation through N⋯Ag + ⋯S interactions. 13 Thus, the extractability (E%) of 2-4 which followed the order of 2 > 3 > 4, may be attributed to the shorter distance, the stronger N⋯Ag + ⋯S interactions, the higher extractability (E%).…”

“…Thus, when 2 complexes with Ag + , the Ag + is easily captured through N⋯Ag + ⋯S interactions. 13 As a result, since the pyridine moieties are orientated inwards, the ring current shielding effect 14 operating in the two thiacalixarene benzene rings is destroyed, forcing the steric conformation change. This affects the protons H 6 , H 5 , H 4 and H 3 of the pyridine rings which shift to lower field, due to the deshielding effect.…”