incorporated into spherosilicate molecules was proved by the appearance of new
signals in the
1 H NMR spectra (d = 3.3 ppm: –N
+
–(CH 3 ) 2 –, d = 3.5 ppm: –N
+
–
CH 2 –) and the decrease in the intensity of the line due to the initial amine group
(d = 2.2 ppm: –N(CH 3 ) 2 ). Additionally, based on
1 H NMR spectra, degrees of
quaternization were calculated. Antimicrobial properties of aqueous solutions of the
prepared compounds as well as of PDMS coating containing them were tested [108,
109].
Nonlinear optical [110, 113], liquid crystalline [111] properties and photoisomerization of the introduced azobenzene moieties [111, 112] of the prepared
materials with azobenzene-based substituents were investigated. Electrochemical
properties of spherosilicate containing carbazole units were evaluated using cyclic
voltammetry, whereas optical properties—by measuring the electronic absorption
and photoluminescence spectra [114]. Spherosilicate modified by isocyanate groups
was applied as the monomer in the synthesis of polyurethane with poly(ethylene
glycol) of various molecular weights and dibutyltin dilaurate serving as the second
monomer and catalyst, respectively [115].
Multistep processes in which hydrosilylation was the first one were used to
incorporate amine groups [116] or adenine, i.e., one of nucleobases, moieties [117]
to Q 8 M 8
H .
The procedure developed by Schäffer and Kickelbick [116] consisted of three
steps. In the first one, Q 8 M 8
H was reacted with x-alkenyl bromides of various chain
lengths (Karstedt’s catalyst, toluene, 80 °C). The resultant cage molecules modified
by bromine-terminated alkyl groups (Table 12.3, S27) were then transformed in the
reaction with NaN 3 to the ones with terminal azide moieties which—after hydrogenation over Pd/C in ethanol—gave quantitatively amine functions. All successive
transformations were accompanied by changes in FTIR and
1 H NMR spectra
(FTIR: no Si–H band at *2200 cm
−1 after hydrosilylation, the band at 2090 cm
−1
due to azide groups after the reaction with NaN 3 which disappeared after hydrogenation;
1 H NMR: no signals at d = 5.74, 4.89 ppm and at d = 4.7 ppm of vinyl
and Si–H groups, respectively, after hydrosilylation, shifts in the signals assigned to
CH 2 unit next to the transformed group—d = 3.41 ppm for CH 2 Br, d = 3.26 ppm
for CH 2 N 3 , d = 2.66 ppm for CH 2 NH 2 , Fig. 12.9a). As revealed by FTIR
(Fig. 12.9b) and
29 Si NMR spectroscopies (disappearance of the band at 557 cm
−1
and the signal at d = −108 ppm, respectively), aminoalkylspherosilicates easily
degraded upon storage with cleavage of their cage structure. They could be,
however, quantitatively converted in situ by treatment with propyl isocyanate to the
hydrogen bond forming spherosilicates with introduced ureido groups. In the
authors’ opinion, these final compounds can interact with appropriate polymers to
yield the materials showing shape memory effect or self-healing properties [116].
Hu et al. [117] reacted Q 8 M 8
H with vinyl benzyl chloride first (Karstedt’s catalyst, toluene, 80 °C). Then, the generated spherosilicate with incorporated benzyl
chloride moieties (Table 12.3, S28) was treated with adenine (DMF, 70 °C, K 2 CO 3
added) to form adenine-substituted cage molecules.
1 H NMR spectra of the reaction
product showed that in the hydrosilylation step, all Si–H groups in Q 8 M 8
H were
392
A. Chechelska-Noworyta et al.
signals in the
1 H NMR spectra (d = 3.3 ppm: –N
+
–(CH 3 ) 2 –, d = 3.5 ppm: –N
+
–
CH 2 –) and the decrease in the intensity of the line due to the initial amine group
(d = 2.2 ppm: –N(CH 3 ) 2 ). Additionally, based on
1 H NMR spectra, degrees of
quaternization were calculated. Antimicrobial properties of aqueous solutions of the
prepared compounds as well as of PDMS coating containing them were tested [108,
109].
Nonlinear optical [110, 113], liquid crystalline [111] properties and photoisomerization of the introduced azobenzene moieties [111, 112] of the prepared
materials with azobenzene-based substituents were investigated. Electrochemical
properties of spherosilicate containing carbazole units were evaluated using cyclic
voltammetry, whereas optical properties—by measuring the electronic absorption
and photoluminescence spectra [114]. Spherosilicate modified by isocyanate groups
was applied as the monomer in the synthesis of polyurethane with poly(ethylene
glycol) of various molecular weights and dibutyltin dilaurate serving as the second
monomer and catalyst, respectively [115].
Multistep processes in which hydrosilylation was the first one were used to
incorporate amine groups [116] or adenine, i.e., one of nucleobases, moieties [117]
to Q 8 M 8
H .
The procedure developed by Schäffer and Kickelbick [116] consisted of three
steps. In the first one, Q 8 M 8
H was reacted with x-alkenyl bromides of various chain
lengths (Karstedt’s catalyst, toluene, 80 °C). The resultant cage molecules modified
by bromine-terminated alkyl groups (Table 12.3, S27) were then transformed in the
reaction with NaN 3 to the ones with terminal azide moieties which—after hydrogenation over Pd/C in ethanol—gave quantitatively amine functions. All successive
transformations were accompanied by changes in FTIR and
1 H NMR spectra
(FTIR: no Si–H band at *2200 cm
−1 after hydrosilylation, the band at 2090 cm
−1
due to azide groups after the reaction with NaN 3 which disappeared after hydrogenation;
1 H NMR: no signals at d = 5.74, 4.89 ppm and at d = 4.7 ppm of vinyl
and Si–H groups, respectively, after hydrosilylation, shifts in the signals assigned to
CH 2 unit next to the transformed group—d = 3.41 ppm for CH 2 Br, d = 3.26 ppm
for CH 2 N 3 , d = 2.66 ppm for CH 2 NH 2 , Fig. 12.9a). As revealed by FTIR
(Fig. 12.9b) and
29 Si NMR spectroscopies (disappearance of the band at 557 cm
−1
and the signal at d = −108 ppm, respectively), aminoalkylspherosilicates easily
degraded upon storage with cleavage of their cage structure. They could be,
however, quantitatively converted in situ by treatment with propyl isocyanate to the
hydrogen bond forming spherosilicates with introduced ureido groups. In the
authors’ opinion, these final compounds can interact with appropriate polymers to
yield the materials showing shape memory effect or self-healing properties [116].
Hu et al. [117] reacted Q 8 M 8
H with vinyl benzyl chloride first (Karstedt’s catalyst, toluene, 80 °C). Then, the generated spherosilicate with incorporated benzyl
chloride moieties (Table 12.3, S28) was treated with adenine (DMF, 70 °C, K 2 CO 3
added) to form adenine-substituted cage molecules.
1 H NMR spectra of the reaction
product showed that in the hydrosilylation step, all Si–H groups in Q 8 M 8
H were
392
A. Chechelska-Noworyta et al.