Identification of face-to-face inclusion complex formation of cyclodextrin bearing an azobenzene group by electrospray ionization mass spectrometry

Abstract

The solution-based self-assembly of native and permethylated cyclodextrins (CD) bearing an azobenzene substituent has been studied by electrospray ionization mass spectrometry (ESI-MS). The results revealed that the CD molecules form either a contact or a face-to-face inclusion complex depending on the interaction of their substituents. The mass spectrometric study further demonstrated that the inclusion complex is formed through the interaction between the host CD cavity and the guest-substituent and that a contact complex is formed by hydrogen-bonding of the hydroxyl functions at the rims of the CD molecule. We also found that in order to detect the face-to-face inclusion complex by ESI-MS, the following conditions have to be met: (1) The CD moieties must be permethylated to avoid formation of the contact complex, (2) they must possess a guest-substituent of suitable length, such as an azobenzene moiety, and (3) they must possess an NH 2 or OH group at the substituent terminals for protonation and for detection as cations by ESI-MS. Formation of the inclusion complexes was further confirmed by the synthesis of a capped inclusion dimer and a capped monomer.

Elimination kinetics and molecular reaction mechanisms of cyclosarin (GF) by an oxime substituted β-cyclodextrin derivative in vitro

“…6). At 5 mM GF (6-OxP-CD:GF ratio 1:10), only bis and tris conjugates were determined with distinctly lower abundances at 5 h. (Arakawa et al, 2003;Guo et al, 2003). The remaining positively charged carbohydrate m/z 163.2 did equally exist as (up to 3-fold) dehydro compounds.…”

Monitoring of complex forming of the active pharmaceutical substance and β-cyclodextrin as an additive of the mobile phase using mass spectrometry

“…Prednost MS u odnosu na druge analitičke metode je pre svega u većoj osetljivosti i jednostavnosti, kao i mogućnosti utvrđivanja stehiometrije, budući da daje podatke o molekulskoj masi. MS elektrosprej jonizacija (ESI-MS) spada u relativno meke tehnike jonizacije, zbog čega ne dovodi do raskidanja slabih nekovalentnih veza u kompleksima koji nastaju između leka i β-CD (13,14).…”

Formation, Structure and Thermal Degradation of the Supramolecular Complex between <em>&beta;</em>-Cyclodextrin and 18-Crown-6

“…However, for the 18C6-β-CD-2, the calculated values are higher than the measured ones, but between those of 18C6 and β-CD, strongly implying that the sample is not a pure complex, but rather a mixture containing 18C6, β-CD, and the complex. ESI-MS has shown itself to be a very useful technique in describing the noncovalent interaction between β-CD and various inorganic and organic guests, [29][30][31] because of its high sensitivity, high speed and low sample consumption. It is worth mentioning that both Peak c and Peak e present extremely low RA values (Peak c, <0.01% ; Peak eʹ, <0.1% ; Peak eʺ, <0.1%) in the ESI mass spectra of the mixed solutions of β-CD and 18C6 in the cases of 1:1 molar ratio and 1:1 mass ratio (see the Supporting Information.).…”