Effective Na⁺-Binding Ability and Molecular Assembly of an Alkylamide-Substituted Penta(ethylene)glycol Derivative

Abstract

A new amphiphilic penta(ethylene glycol) derivative (1) bearing two hydrogen-bonding −CONHC 14 H 29 chains was prepared. Compound 1 exhibited ion-recognition abilities for Na + and K + , and its properties were compared with those of the macrocyclic [18]crown-6. Although both compound 1 and [18]crown-6 have six ether oxygen atoms (−OC 2 H 2 −), the Na +binding ability of the former was much higher than that of the latter. K + -binding ability of cyclic [18]crown-6 was much higher than its Na + -binding ability, while the reverse was true for acyclic compound 1. Single-crystal X-ray structural analysis of Na + •1• B(Ph) 4 − •(hexane) 2 at 100 K revealed the existence of a wrapped Na + -coordination by six ether and one carbonyl oxygen atoms of 1, which was further stabilized by intramolecular N−H•••O hydrogen-bonding interactions. The complex phase transition during glass (G) formation and recrystallization was confirmed in the thermal cycle of Na + •1•B(Ph) 4 − , whose molten state showed two kinds of liquid phases, Na + -complexed (Na + •1) + B(Ph) 4− and completely dissociated Na + + 1 + B(Ph) 4 − . The Na + conductivity of the molten state was 2 orders of magnitude higher than that of the G phase.

Electrospray Gold Standards of Molecular Mass 32- to 52-kDa: Charging Patterns of the Ubiquitous Virus-like Clusters, I - 197Au144-5(SR)60, R = 8 Variants, in Native [HPLC]-ESI-MS

“…Tetra ethylene glycol units are known to bind sodium ions well. 41 In the spectrum shown in Figure 3 (h) the distribution having the highest signal strength ranges from 7 + to 11 + , with 9 + being the most abundant. The intact mass determined from the sequence of higher abundance charge states is consistent with a {n, p; 144, 60} cluster, (where n, p represent the number of Au atoms and thiols, respectively).…”