Supramolecular inclusion complexes of a star polymer containing cholesterol end‐capped poly(ε‐caprolactone) arms with β‐cyclodextrin

Abstract

A novel hexa-armed and star-shaped polymer containing cholesterol end-capped poly(e-caprolactone) arms emanating from a phosphazene core (N 3 P 3 -(PCL-Chol) 6 ) was synthesized by a combination of ring-opening polymerization and "click" chemistry techniques. For this purpose, the terminal AOH groups of the synthesized precursor (N 3 P 3 -(PCL-OH) 6 ) were converted into -Chol through a series of reaction. Both N 3 P 3 -(PCL-OH) 6 and N 3 P 3 -(PCL-Chol) 6 were then employed in the preparation of supramolecular inclusion complexes (ICs) with b-cyclodextrin (b-CD). The latter formed ICs with b-CD in higher yield. The host-guest stoichiometry (e-CL:b-CD, mol:mol) in the ICs of N 3 P 3 -(PCL-Chol) 6 was found to be 1.2. The formation of supramolecular ICs of N 3 P 3 -(PCL-Chol) 6 with b-CD was confirmed by using Fourier transform infrared (FTIR) and 1 H nuclear magnetic resonance (NMR) spectroscopic methods, wide-angle X-ray diffraction (WAXD), and thermal analysis techniques. WAXD data showed that the obtained ICs with N 3 P 3 -(PCL-Chol) 6 had a channel-type crystalline structure, indicating the suppression of the original crystallization of N 3 P 3 -(PCL-Chol) 6 in b-CD cavities. Moreover, the thermal stabilities of ICs were found to be higher than those of the free star polymer and b-CD. Furthermore, the surface properties of N 3 P 3 -(PCL-Chol) 6 and its ICs with b-CD were investigated by static contact angle measurements. The obtained results proved that the wettability of N 3 P 3 -(PCL-Chol) 6 successfully increased with the formation of its ICs with b-CD. V C 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 3406-3420

Polyrotaxane-based supramolecular theranostics

“…2c ). XRD diffractograms of β -CD-NH 2 indicated a series of peaks ranging from 5° to 40°, confirming the macrocyclic structure 17 . PDI-PCL- b -PEG-Mal, a semicrystalline material with orthorhombic crystal structure, exhibited two distinct diffraction peaks at 22° and 24°, related to (110) and (200) lattice structures, respectively 18 .…”

“…13 ), the characteristic peaks for β -CD-NH 2 (1029, 1157, and 3347 cm −1 , corresponding to the C–O bending vibration, C–O stretching, and O–H bending vibration, respectively) and PCL segment (1168, 1727, and 2887/2944 cm −1 , corresponding to symmetric C–O–C stretching, C=O stretching, asymmetric/symmetric –CH 2 – stretching, respectively) were observed, indicating the presence of these components. In comparison with the spectrum of PDI-PCL- b -PEG-Mal, the intensity of the peak at 1727 cm −1 for PDI-PCL- b -PEG-RGD⊃ β -CD-NH 2 was much lower, because the carbonyl groups of the PCL chains were included in β -CD-NH 2 cavities 17 . The X-ray diffraction pattern (XRD) of the freeze-dried PDI-PCL- b -PEG-RGD⊃ β -CD-NH 2 was substantially different from those of PDI-PCL- b -PEG-Mal and β -CD-NH 2 (Fig.…”

Synthesis of Miktoarm Star‐Shaped Polymers with POSS Core via a Combination of CuAAC Click Chemistry, ATRP, and ROP Techniques

“…(PCL) 8 -POSS-(N 3 ) 8 was synthesized according to the literature method. [ 40 ] Tin octoate (Sn(Oct) 2 ) (0.04 g, 0.09 mmol), POSS-(N 3 ) 8 (0.19 g, 0.11 mmol), and ε -CL (2.07 g, 18.13 mmol) were added to a fl ame-dried reaction fl ask equipped with a magnetic stirring bar in that order. The reaction mixture was deoxygenated by purging gently with oxygen-free argon for 10 min.…”

Sequential Reactions for Post-polymerization Modifications

“…In the first step, the terminal hydroxyl group was treated with 3-bromopropyne to introduce an alkyne group, which could be clicked with an azide-functionalized phenolphthalein derivative in the second step (Scheme 32). The core preparation was based on dipentaerythrol, whose hydroxyl groups were transformed into alkynes using an alkyne-carrying acid bromide, as described in the literature [66,69]. This triple bond was necessary to attach azide-modified cyclodextrin onto the core.…”