Hydrogen bonding of excited states in supramolecular host–guest inclusion complexes

Abstract

Host-guest inclusion complexes represent an important type of supramolecular structure, one which finds widespread applications in diverse areas including separations science, the food industry, molecular sensors and optical devices. There are several driving forces for the formation of such inclusion complexes in solution; one of the most important is hydrogen bonding between the guest and host molecules. The nature or strength of the hydrogen bonding may change upon electronic excitation of the guest, for example during fluorescence studies or when the inclusion complex is used as an optical sensor. In this Perspective article, the impact of hydrogen bonding between excited state guests and their hosts is examined in detail, in terms of the impact on the formation and stability of such excited state complexes, the effects on guest fluorescence, changes in the stability of ground state guest complexes upon electronic excitation, the application of inclusion complexes as fluorescent sensors and materials, and the use of fluorescence spectroscopy for their study.

Hydrogen-bonding dynamics of photoexcited coumarin 138 and 339 in protic methanol solution: Time-dependent density functional theory study

“…Intermolecular hydrogen bond is one of the site-specific interactions, which plays a fundamental role in molecular photochemistry of organic and biological chromophores in solution [1][2][3][4][5][6][7]. This intermolecular interaction can assemble multiple molecules into a cluster, which is formed in the ground state and influence a series of photophysical processes, such as internal conversion (IC), photoinduced proton transfer (PPT), and photoinduced electron transfer (PET) [8][9][10][11][12][13][14].…”

Complexation and Chiral Recognition of Chiral Binaphthyl Derivatives and β-Cyclodextrins in Solution Probed by Triplet Excited State Relaxation

“…Despite chiral recognition by CDs concerns ground state interactions and extensive investigations have been devoted in this regard [1][2][3][4][5][6][7], there is an increasing trend in the past decade towards exploring such interactions via dynamics in the excited states. The importance of these studies is related to the applications of supramolecular photochemistry in a number of intriguing key fields such as photoresolution, photochirogenisis, and photochemical asymmetric synthesis [9][10][11][12][13][14][15][16]. However, very few examples on the direct chiral recognition involving CDs or other host molecules in the excited triplet state were reported in the literature [17][18][19][20][21][22][23].…”

Modulation of Twisted Intramolecular Charge Transfer Emission of 2‐(4′‐N,N‐Dimethylaminophenyl)imidazopyridines in Aqueous Cucurbit[7]uril+

“…Supramolecular systems with improved host‐guest interactions have been a topic of growing research interest. Further, these host‐guest bindings are used to modulate the photophysical and photochemical properties of the various organic dyes . To date, variety of host systems such as cyclodextrins (CDs), calixarenes, octa‐acids, cucurbit[n]urils (CBns) are used to encapsulate the guest molecules .…”

“…To date, variety of host systems such as cyclodextrins (CDs), calixarenes, octa‐acids, cucurbit[n]urils (CBns) are used to encapsulate the guest molecules . CBns are water soluble macrocylic hosts and have different number (n) of glycoluril units connected by a pair of methylene linkers ,. CBns are classified into different types, depending on the number of gycouril units .…”