Synthesis and Evaluation of Thioether-Based Tris-Melamines as Components of Self-Assembled Aggregates Based on the CA·M Lattice
作者:Xinhua Li、Donovan N. Chin、George M. Whitesides
DOI:10.1021/jo951098g
日期:1996.1.1
Two new tris-melamine derivatives, triazine-thio-M(3) (5) (C3N3-2,4,6-[SCH2C6H4-3-N(CH2C6H4-4C(CH3)(3))COC6N3-2- NHC3N3(NH2)(NHCH2CH2CH3)(3)-5-Br](3)) and benzene-thio-M(3) (6) (C6H3-1,3,5-[SCH2C6H4-3-N(CH2C6H4-4-C(CH3)(3))COC6H3-2-NH2)(NHCH2CH2C(CH3)(3))-5-Br](3)), were synthesized by reactions of 2,4,6-trithiocyanuric acid and 1,3,5-trimercaptobenzene with a bromobenzyl melamine derivative 19 (BrCH2C6H4-3-N(CH2C6H4-4-C(CH3)(3))COC6H3-2NHC(3)N(3)(NH2)(NHCH2CH2C(CH3)(3))-5-Br). These two compounds formed stable and structurally well-defined 1 + 3 supramolecular aggregates with neohexyl isocyanurate (R'CA) (9) as shown by NMR spectroscopy and gel permeation chromatography. H-1 NMR competition experiments indicated that the stability of triazine-thio-M(3) .(R'CA)(3) (1) was similar to that of benzene-thio-M(3) .(R'CA)(3) (2). The order of stabilities of tris-melamine-based 1 + 3 complexes was hubM(3) .(R'CA)(3) (3) > triazine-thio-M(3) .(R'CA)(3) (1) similar to benzene-thio-M(3) .(R'CA)(3) (2) > flexM(3) .(R'CA)(3) (4). Computational simulations were also carried out on triazine-thio-M(3) .(R'CA)(3) and hubM(3) .(R'CA)(3) fully solvated in CHCl3. Values of DP (the deviation from planarity of the cyanuric acid and melamine rosette) obtained from these simulations correlated correctly with the observed stabilities and suggested a structural reason why triazinethio-M(3) .(R'CA)(3) was less stable than hubM(3) .(R'CA)(3).