Hydrazide-Based Quadruply Hydrogen-Bonded Heterodimers. Structure, Assembling Selectivity, and Supramolecular Substitution

Abstract

This paper describes the synthesis, self-assembly, and characterization of a new class of highly stable hydrazide-based quadruply hydrogen-bonded heterodimers. All of the hydrazide-derived heterodimers possess the complementary ADDA-DAAD hydrogen-bonding sequences. Hydrazide derivatives 1, which has two intramolecular S(6) RO.H-N hydrogen bonds, and 2 complex to afford two fastly exchanging isomeric heterodimers 1.2 and 1.2' in chloroform, as a result of two different conformational arrangements of 2. An average binding constant K(assoc) of 4.7 x 10(4) M(-)(1) was determined for heterodimer 1.2 and 1.2' by (1)H NMR titration of 1 with changing 2 in chloroform-d. In contrast, 1 binds 11 and 12, both of which are introduced with two intramolecular S(6) hydrogen bonds, to exclusively afford heterodimers 1.11 and 1.12, with K(assoc) values of 1.8 x 10(4) and 5.0 x 10(2) M(-)(1), respectively. Fluorine-containing 19, which has a hydrazide skeleton identical to that of 1 but two intramolecular S(6) F.H-N hydrogen bonds, can also complex with 2, 11, and 12, to afford heterodimers 19.2, 19.2', 19.11, and 19.12, with K(assoc) values of of 1.2 x 10(4) (average value for 19.2 and 19.2'), 5.4 x 10(3), and 1.9 x 10(2) M(-)(1), respectively. The structures of the new heterodimers have been proven with NOESY, IR, and VPO (for some of the heterodimers) experiments. Moreover, 1 and 19 can also strongly bind 2,7-dilauroylamido-1,8-naphthyridine 23 to afford dimers 1.23 and 19.23 with K(assoc) values of 6.0 x 10(5) and 1.4 x 10(5) M(-)(1), respectively. Adding 1 to the 1:1 solution of 23 and 1-octyl-3-(4-oxo-3,4-dihydro-pyrido[2,3-d]pyrimidin-2-yl)urea 24 or 1-octyl-3-(4-oxo-1,4-dihydro-pyrimidin-2-yl)urea 25, which had been developed initially by Zimmerman and Meijer, respectively, induces dimers 23.24 and 23.25 to dissociate, leading to the formation of dimers 1.23 and 24.24 or 25.25, respectively. The new hydrazide-based hydrogen-bonding modules described are useful building blocks for self-assembly and open a new avenue to recognition between discrete supramolecular species.

Phase Behavior of Complementary Multiply Hydrogen Bonded End-Functional Polymer Blends

“…The supramolecular diblock architecture was chosen due to the ease with which the chain end-functionalized linear homopolymers could be synthesized, with the well-studied quadruple hydrogen bonded dimer of 2-ureido-4[1H]-pyrimidinone (UPy) and 2,7-diamido-1,8-naphthyridine (Napy) 40,[52][53][54][55][56][57] serving as the reversible link between them.…”

Model Transient Networks from Strongly Hydrogen-Bonded Polymers

“…Additionally, supramolecular gels based on hydrogen bonding in ionic liquids have been demonstrated and their rheological properties related to the strength and number of hydrogen bonds as well as stoichiometry of donor and acceptor units. 29,30 To broaden the scope and applicability of supramolecular polymer chemistry, many new strongly hydrogen-bonding moieties have been synthesized [31][32][33][34][35][36][37] and incorporated into networkforming materials. [12][13][14][15][38][39][40][41] The strength and specificity of multiple-hydrogen-bonded (MHB) groups vary widely, from weakly complementary pyridine-phenol pairs 42 to extremely strong, self-complementary 6-H-bonded dimers.…”

Strapped porphyrin rosettes based on the melamine–cyanuric acid motif. Self-assembly and supramolecular recognition

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] Because of its unique feature of directionality, specificity, and stability, hydrogen bonding has been one of the most versatile non-covalent forces for the self-assembly of well-defined supramolecular systems. [17][18][19][20][21] Over the years, a number of efficient triple and quadruple hydrogen bonding modes have been developed. [17][18][19] The triply hydrogen bonded melamine-cyanuric acid motif has been extensively studied for the formation of the so-called 'rosette' supramolecuar structures.…”