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CDCl3): d=À6.04, À5.79, 14.65, 20.63, 39.04, 125.86, 128.33, 129.08,
142.45 ppm; GC-MS [m/z (%)]=178 [M]+, 163 (19), 145 (7), 135
(54), 118 (90), 100 (65), 91 (51), 85 (16), 59 (100), 43 (17).
3H); 13C NMR (75 MHz, CDCl3): d=À5.97, À5.89, 15.49, 20.90,
27.16, 126.82, 128.89, 133.80, 142.35. GC-MS [m/z (%)]=194 [M]+,
179 (1), 151 (6), 118 (17), 91 (6), 75 (100), 47 (4), 38 (1).
(1-(4-fluorophenyl)ethyl)dimethylsilanol (2g): 1H NMR (300 MHz,
CDCl3): d=7.05–76.96 (m, 4H), 2.27–2.19 (q, J=7.4 Hz, 1H), 1.39–
1.36 (d, J=7.5 Hz, 3H), 0.09 (s, 3H), 0.08 ppm (s, 3H); 13C NMR
(75 MHz, CDCl3): d=À2.51, À2.29, 14.43, 30.11, 114.84,115.12,
128.13, 128.23, 140.20 ppm; GC-MS [m/z (%)]=198 [M]+, 183 (2),
155 (10), 122 (32), 104 (100), 96 (13), 75 (99), 61 (4), 47 (12), 39(2).
General procedure for the preparation of silanols (2a–j)
In a 2 mL microtube (Eppendorf) containing organosilanes (1a–j)
(0.025 mmol), H2O (50 mL), NSs (5 mol% calculated with respect to
Au, Pt or Pd) and acetone (1 mL) were added. The mixture was
stirred for 1 h at room temperature. After the catalyst was removed
via centrifugation and the reaction content was analyzed via GC-
MS. The reaction, when necessary, was purified by column chroma-
tography (silica gel) using hexane/acetate as eluent.
Dimethyl(1-phenylpropan-2-yl)silanol(2h): 1H NMR (300 MHz,
CDCl3): d=7.34–7.16 (m, 5H), 2.91–2.85 (dd, J=3.0, 13.0 Hz, 1H),
2.45–2.36 (dd, J=6.0 Hz; J=13 Hz, 1H), 1.13–1.06 (m, 1H), 0.92–
0.90 ppm (d, J=6.0 Hz, 1H); 13C NMR (75 MHz, CDCl3): d=À6.26,
À6.01, 14.43, 20.42, 38.42, 125.61, 123.10, 128.84, 142.21 ppm; GC-
MS [m/z (%)]=194 [M]+, 176 (7), 161 (4), 152 (4), 137 (18), 118 (32),
91 (10), 75 (100), 61 (8), 47(8).
General procedure for the recycling studies
In a 2 mL microtube (Eppendorf) containing dimethyl(phenyl)silane
(1a) (0.025 mmol), H2O (50 mL), NSs (5 mol% calculated with re-
spect to Au, Pt or Pd) and acetone (1 mL) were added. The mixture
was stirred for 1 h at room temperature. After this period, the reac-
tion mixture was centrifuged for 5 min at 8500 rpm to facilitate the
removal of the reaction content and catalyst recycling. The catalyst
was washed with acetone (1 mL), sonicated for 10 min and then
the mixture was centrifuged for 5 min at 8500 rpm. This protocol
was repeated for more two times. The reaction content was ana-
lyzed via GC-MS. The nanoparticles were used for a new reaction
cycle as described above.
1
Dimethyl(2-phenylethyl)silanol (2i): H NMR (300 MHz, CDCl3): d=
7.28–7.13 (m, 5H), 2.73–2.66 (t, J=9 Hz, 2H), 1.00–0.95 (t, J=9 Hz,
2H), 0.14 ppm (s, 6H); 13C NMR (75 MHz, CDCl3): d=À4.52, 16.18,
30.53, 125.56, 127.81, 128.28, 144.77 ppm; GC-MS [m/z (%)]=180
[M]+, 165 (25), 147 (24), 137 (34), 104 (11), 91 (7), 75 (100), 61 (23),
45 (12).
Cyclohexyldimethylsilanol (2j): 1H NMR (300 MHz, CDCl3): d=
1.76–1.72 (m, 5H), 1.40–1.14 (m, 5H), 0.10 ppm (s, 6H); 13C NMR
(75 MHz, CDCl3): d=À2.27, 26.87, 26.66, 27.80, 27.41 ppm; GC-MS
[m/z (%)]=158 [M]+, 143 (5), 115 (2), 101 (2), 75 (100), 61 (16), 45
(7), 41 (4).
Dimethyl(1-phenyl)silanol (2a): 1H NMR (300 MHz, CDCl3): d=
7.62–7.60 (m, 2H), 7.41–7.39 (m, 3H), 0.42 ppm (s, 6H); 13C NMR
(75 MHz, CDCl3): 0.87, 127.70, 129.24, 133.00, 139.82 ppm; GC-MS
[m/z (%)]=152 [M]+, 137 (100), 119 (3), 91 (7), 75 (5), 69 (4), 45
(13).
General procedure for CALB attachment onto NSs (NSs-
CALB)
4-(hydroxydimethylsilyl)benzonitrile (2b): 1H NMR (300 MHz,
CDCl3): d=7.63–7–62 (m, 4H), 0.38 (s, 3H), 0.36 (s, 3H); 13C NMR
(75 MHz, CDCl3): d=À4.16, 112.79, 118.91, 131.03, 134.46,
144.30 ppm; GC-MS [m/z (%)]=177 [M]+, 162 (100), 146 (1), 130
(1), 117 (3), 103 (4), 91 (10), 75 (12), 59 (6), 45(24).
In a 2 mL microtube (Eppendorf) containing nanoshells (AgAu NSs,
AgPt NSs, and AgPd NSs, 5 mol% calculated with respect to Au, Pt,
or Pd) was added 1 mL of lipase solution (solution of Candida ant-
arctica lipase: 0.145 mgmLÀ1) in 20 mm phosphate buffer (pH 7).
The resulting mixture was stirred at 328C for 2 h under 800 rpm
(Thermomixerꢁ apparatus). The functionalized NSs with lipases
were removed from the reaction mixture by centrifugation, and
then washed with water (32 mL). The resulting aqueous solution
was used to evaluate the residual amount of protein. The NSs-
CALB systems (AgAu NSs-CALB, AgPt NSs-CALB, and AgPd NSs-
CALB) were stored in phosphate buffer (pH 7.0, 1 mL) for further
studies.
Dimethyl(naphthalen-2-yl)silanol (2c): 1H NMR (300 MHz, CDCl3):
d=8.04–8.03 (m, 1H), 7.81–7.76 (m, 3H), 7.64–7.61 (m, 1H), 7.47–
7.45 (m, 2H), 0.43 (s, 6H), 0.38 ppm; 13C NMR (75 MHz, CDCl3): d=
0.93, 125.83, 126.36, 126.94, 127.68, 128.20, 129.36, 132.82, 133.77,
133.87, 137.20 ppm; GC-MS [m/z (%)]=202 [M]+, 187 (100), 169
(23), 141 (9), 128 (15), 115 (9), 101 (3), 93 (15), 75 (7), 45(14).
1-(4-(hydroxydimethylsilyl)phenyl)ethanone
(2d):
1H NMR
(300 MHz, CDCl3): d=7.92 (dd, J=8.2, 5.2 Hz, 1H), 7.66 (dd, J=
21.6, 8.2 Hz, 1H), 2.93–2.84 (s; 1H), 0.90 (s, 3H), 0.13 (s, 3H),
0.12 ppm (s, 3H); 13C NMR (75 MHz, CDCl3): d=À0.01, 0.70, 26.64,
127.35, 129.97, 133.28, 137.67, 145.63, 176.80 ppm; GC-MS [m/z
(%)]=194 [M]+, 179 (100), 161 (3), 151 (4), 136 (7), 121 (6), 105 (2),
91 (6), 75 (18), 45(12). 176.80, 145.63, 137.67, 133.28, 129.97,
127.35, 26.64, 0.70, À0.01.
Dimethyl(1-phenylethyl)silanol (2e): 1H NMR (200 MHz, CDCl3):
d=7.30–7.10 (m, 5H), 2.30–2.22 (q, J=7.5 Hz, 1H), 1.41–1.39 (d,
J=7.5 Hz, 3H), 0.10 (s, 3H), 0.08 ppm (s, 3H); 13C NMR (50 MHz,
CDCl3): d=À2.54, À2.23, 14.14, 30.93, 124,63, 127.06, 128.29,
144.62 ppm; GC-MS [m/z (%)]=180 [M]+, 165 (1), 149 (1), 137 (7),
104 (12), 91 (1), 75 (100), 75 (100), 45 (6).
Quantification of proteins immobilized onto the bimetallic
NSs
The protein content was determined by Bradford method.[40] A cali-
bration curve was obtained at 595 nm in spectrophotometer (Bio-
spectro, sp-220), by the use of bovine serum albumin (BSA) as
standard protein solution in different concentrations.
Enzyme activity: transesterification reaction of (RS)-1-(phe-
nyl)ethanol(4) with vinyl acetate
In a 2 mL microtube (Eppendorf) containing the NSs-CALB systems
(AgAu NSs-CALB, AgPt NSs-CALB, and AgPd NSs-CALB, 62.5 mol%
calculated with respect to Au, Pt, or Pd), (RS)-1-(phenyl)ethanol
(0.002 mmol) and vinyl acetate (0.07 mmol) were dispersed in tolu-
Dimethyl(1-(p-tolyl)ethyl)silanol (2 f): H NMR (300 MHz, CDCl3):
d=7.11–6.98 (dd, J=29.5, 8.0 Hz, 4H), 3.86–3.83 (q, J=7.4, 1H),
2.33 (s, 3H), 1.41–1.38 (d, J=7.5 Hz, 3H), 0.05 (s, 3H), 0.01 ppm (s,
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