Non-covalent bonded 1D-3D supramolecular salts from tert‑butylamine and organic acids

Abstract

Cocrystallization of the widely available simplest voluminous primary amine, tert‑butylamine, with a set of acids got a total of 14 salts, which have been featured by XRD technique, Infrared spectra and elemental analysis. Their melting points were also surveyed. Their structural and supramolecular aspects are analyzed in detail. All compounds are ionic, with H-transferring to the NH2 of the tert‑butylamine. The results unveil that among all the studied crystals the NH2 in L are protonated when the acids are deprotonated, the crystal packing is interpreted via the strong NH⋯O H-bond from the NH3+ and the deprotonated acids. Apart from the NH⋯O H-bond, the OH···O H-bonds were also existed at 6 and 12. Salts 1 - 2 had the NH⋯S H-bond. The NH···Cl H-bond existed in 7. Further view of the crystal packing told that a different array of additional CH3···S, O···Cl, S···S, CH3···C, CH3···CH3, CH···O/CH3···O, CH2···Cl, CH···N, CH3···π and π···π contacts help the stabilization and expansion of the whole structures. For the synergism of the various nonbonding contacts these structures had the hetero supramolecular synthons. Some classical synthons of R22(8), R42(8), R43(10) and R44(12), commonly present in solids of organic acids with amine, were again shown to be created in making these H-bonding nets.