Abstract:
Sterically encumbered 2,6-di-tert-butylphenyl phosphate (dtbpph2) (1) has been synthesized in two steps from the reaction of either the lithium or sodium salt of 2,6-di-tert-butylphenol with pocl3, followed by controlled hydrolysis of the resultant (aro)p(o)cl2. Phosphate ester 1 has been characterized by analytical, spectroscopic, and single crystal x-ray diffraction studies. Crystallization of 1 in dimethylformamide (dmf) solution results in solvent decomposition to produce dimethyl amine, which then interacts with 1 to form the adduct [(me2nh2)(dtbpph)]2·h2o (2). The presence of two acidic protons in 1 prompted us to investigate its supramolecular aggregation behaviour in the presence of aliphatic and aromatic amines such as 1,4-diazabicyclo[2.2.2]octane (dabco) and 4,4′-bipyridine (bpy), producing the adducts [(dabco-h)(dtbpph)] (3) and [(bpy-h2)(dtbpph)2(dtbpph2)]·meoh (4), respectively. One-dimensional polymeric aggregation was observed for adduct 3 mediated by the presence of alternating 1,4-diazabicyclo[2.2.2]octan-1-ium cations and phosphate monoanions. Polymer 4 displays an interesting 1-d zigzag polymeric structure that contains alternating phosphate trimers and 4,4′-bipyridinium dications; the phosphate trimer itself is made up of a benzoic acid type dimer and a monomer which are linked together by p-o-h-o-p hydrogen bonds. In order to unravel the effect of steric bulkiness on the supramolecular aggregation, [(bpy-h)(dipph)] (5) and [(pip-h2)(dipp)] (6), the adducts formed by relatively less-bulkier 2,6-diisopropylphenyl phosphate (dipph2) with piperazine (pip) and 4,4′-bipyridine have been investigated. © 2022 the royal society of chemistry.