6533b861fe1ef96bd12c442b

RESEARCH PRODUCT

Encapsulation of tetramethylphosphonium cations

subject

description

International audience; The weak interactions and capsule formation of tetramethylphosphonium (TMP) cation with resorcinarenes 1 and 2 and the corresponding pyrogallarenes 3 and 4 were studied in the solid state by single crystal X-ray diffraction, in solution by NMR and in the gas phase by mass spectrometry. In methanol-D4, the NMR titration studies reveal that the association constants for the 1:1 complexes of TMP@3 and TMP@4 are much higher (TMP@4:390±37 M-1) than for the corresponding TMP@1 and TMP@2 (TMP@2:130±10 M-1) complexes. In the gas phase both monomeric 1:1 TMP@1-TMP@4 complexes as well as the dimeric 1:2 capsule complexes, TMP@12-TMP@42 were observed. The 1:1:2 molar mixtures of 1:2:TMP or 3:4:TMP resulted in homo- and heterocapsules TMP@12, TMP@1+2 and TMP@22 with the expected statistical 1:2:1 ratio. Using 1:1:2 ratio of 1:3:TMP, 1:4:TMP, 2:3:TMP or 2:4:TMP showed a marked prefence to the homopyrogallarene capsules TMP@32 and TMP@42 thus supporting the stronger complexation of TMP with 3 and 4 as observed in solution. The X-ray structures confirmed the dimeric capsular structures with only minor structural differences to the corresponding tetramethylammonium (TMA) capsules reported earlier.