Synthesis and Structures of Infinite Coordination Polymers from 1,3-Bis(4-pyridyl)propane Ligand and Zinc Salts

Host-Guest Complexes of C-Ethyl-2-methylresorcinarene and Aromatic N,N'-Dioxides

The C‐ethyl‐2‐methylresorcinarene (1) forms 1:1 in‐cavity complexes with aromatic N,N′‐dioxides, only if each of the aromatic rings has an N−O group. The structurally different C‐shaped 2,2′‐bipyridine N,N′‐dioxide (2,2′‐BiPyNO) and the linear rod‐shaped 4,4′‐bipyridine N,N′‐dioxide (4,4′‐BiPyNO) both form 1:1 in‐cavity complexes with the host resorcinarene in C_4v crown and C_2v conformations, respectively. In the solid state, the host–guest interactions between the 1,3‐bis(4‐pyridyl)propane N,N′‐dioxide (BiPyPNO) and the host 1 stabilize the unfavorable anti‐gauche conformation. Contrary to the N,N′‐dioxide guests, the mono‐N‐oxide guest, 4‐phenylpyridine N‐oxide (4PhPyNO), does not form an in‐cavity complex in the solid state. The host–guest complexation and the relative guest affinities were studied through ¹H NMR competition experiments in methanol. Single‐crystal X‐ray crystallography of the 1:1 complexes supports the proposed solution‐state structures, also revealing strong hydrogen bonds between the host and the guests, not observed in solution owing to hydrogen/deuterium (H/D) exchange processes in methanol.

Molecular structure and vibrational spectra of 1,3-bis(4-pyridyl)propane by quantum chemical calculations

The experimental and theoretical study on the structures and vibrations of 1,3-bis(4-pyridyl)propane are presented. The FT-IR and Raman spectra of molecule have been measured. The optimized geometric bond lengths have been obtained by DFT show the best agreements with experimental values. The harmonic vibrational frequencies were calculated and scaled values have been compared with experimental FT-IR and FT-Raman spectra. Majority of the computed wavenumbers were found to be in good agreement with experimental observations. A complete assignment of the fundamentals was proposed based on the total energy distribution (TED) calculation.