Propeller-shaped molecules with a thiazole hub: structural landscape and hydrazone cap mediated tunable host behavior in 4-hydrazino-1,3-thiazoles

Abstract

Propeller-shaped molecules with 2,4,5-trisubstituted-1,3-thiazole as the hub and tunable blades (B₁–B₃) were synthesized as trivariant scaffolds. B₁–B₃ were modulated by varying the hydrazone capping in B₁, the isothiocyanate in B₂ and the α-haloketone in B₃ and the structural landscapes examined. Multicomponent molecular crystals formed nitrogen rich channels (NRCs) of varied shapes and dimensions which were largely steered by the substitution pattern in B₁ and established by varying carbonyl components. Isopropylidene derivatives (IPHAT) stabilized single file water inside the NRC (~34 Ų) between B₁ and B₂, benzylidene derivatives (BzHAT) formed a constricted NRC and accommodated solvates inside a hydrophobic cavity between B₁ and B₃ whereas a pincer-shaped NRC devoid of guest molecules was formed by cyclohexylidene derivatives (CyHAT). The hydrazone substituent-driven variation in solid state landscapes indicates a wide scope of expandability of these thiazole templates as supramolecular synthons for tunable hosts.