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ble for X-ray analysis. (0.020 g, 0.022 mmol, 25%); MS (ESI+) m/z:
calcd for C31H35F6N6Ni2O5P·MeOH: 659 [M–PF6–OAc–H]+; found:
659; elemental analysis. calcd (%) for C31H35F6N6Ni2O5P·MeOH: C
44.38, H 4.54, N 9.70; found C 44.30, H 4.48, N 9.60.
adsorb arsenate efficiently over a wide pH range, with the
maximum adsorption occurring at pH 7. Adsorption from solu-
tions containing high levels of competing ions and from natu-
ral groundwaters demonstrates that Zn–HypoGel performs
much better than Bayoxide E33 and therefore has potential for
use in water remediation. Furthermore, Zn–HypoGel could also
be regenerated and re-used by simply washing with a basic
sodium acetate solution and showed no loss of performance
even after multiple desorption cycles. Put together, these re-
sults show that our new functionalised polymeric material per-
forms better than the currently used adsorbent Bayoxide E33.
Crystal data for 5
[C31H35N6Ni2O5](PF6)·MeOH, M=866.08, monoclinic, P21/c (no. 14),
a=10.52058(6),
b=14.41429(10),
c=24.21878(16) ꢂ,
b=
96.3228(6)8, V=3650.36(4) ꢂ3, Z=4, 1cald =1.576 gcmꢀ3, m(CuKa)=
2.427 mmꢀ1, T=173 K, blue/pale blue dichroic blocky needles,
Oxford Diffraction Xcalibur PX Ultra diffractometer; 7118 independ-
ent measured reflections (Rint =0.0214), F2 refinement,[33] R1(obs)=
0.0282, wR2(all)=0.0732, 6437 independent observed absorption-
corrected reflections [jFo j >4s(jFoj), 2qmax =1458], 486 parameters.
Experimental Section
General
Crystal data for 7
Ligand L2, metal complexes 1–4 and 6, and compounds 8–10 were
prepared by slight modifications of previously reported procedures
(see the Supporting Information for details).
[C68H76As2N12O12Zn4](BF4)2·2MeOH, M=1902.43, monoclinic, P21/
c
(no. 14), a=19.3412(3), b=14.3874(2), c=28.4490(3) ꢂ, b=
94.4691(12)8, Z=4,
V=7892.42(18) ꢂ3, 1cald =1.601 gcmꢀ3
,
m(MoKa)=2.121 mmꢀ1, T=173 K, colourless tablets, Oxford Diffrac-
tion Xcalibur 3 diffractometer; 26853 independent measured re-
flections (Rint =0.0405), F2 refinement,[33] R1(obs)=0.0579, wR2(all)=
0.1416, 17000 independent observed absorption-corrected reflec-
tions [jFo j > 4s(jFoj), 2qmax =668], 1073 parameters.
2,6-Bis((bis(pyridin-2-ylmethyl)amino)methyl)-4-methylphe-
nol (L1)
This Finkelstein activation was carried out under solvent-free con-
ditions. Di-(2-picolyl)amine (1.1 mL, 6 mmol), potassium iodide
(0.499 g, 3 mmol), potassium carbonate (1.001 g, 3 mmol) and PEG-
400 (0.1 mL, 0.3 mmol) were ground together with a mortar and
pestle for 5 mins to form a yellow paste. 2,6-Bis(chloromethyl)-4-
methylphenol (0.620 g, 3 mmol) was added and the resulting
green paste was ground vigorously for 45 min, yielding a sticky
green solid. This material was taken up in CH2Cl2 and washed with
water until the aqueous layer was no longer cloudy. The organic
layer was then dried overnight with sodium sulfate and filtered.
The solvent was removed under reduced pressure to give a green
oil (crude yield 88%); this was recrystallised from 1:1 hexane/ether
to give the desired product, L1, as a yellowish solid. (0.848 g,
1.6 mmol, yield 54%); m.p.=95–978C; 1H NMR (400 MHz, CDCl3):
d=10.79 (s, 1H, ꢀOH), 8.54 (d, 4H, J=4.5 Hz, PyꢀH), 7.62 (td, 4H,
J=7.8 Hz, 1.8 Hz, PyꢀH), 7.52 (d, 4H, J=7.8 Hz, PyꢀH), 7.14 (m, 4H,
PyꢀH), 7.01 (s, 2H, ArH), 3.89 (s, 8H, PyCH2), 3.80 (s, 4H, ArCH2),
2.25 (s, 3H, ArCH3); 13C NMR (100 MHz, CDCl3): d=159.3, 148.9,
136.5, 129.8, 123.7, 123.0, 122.0, 77.4, 77.1, 76.8, 59.8, 54.8; MS
(ESI+): m/z: calcd for C33H34N6O: 531.29 [M+H]+; found: 531.29; el-
emental analysis calcd (%) for. C33H34N6O·0.5H2O: C 73.44, H 6.54, N
15.57; found C 73.81, H 6.38, N 15.34.
CCDC-995883 (5) and CCDC-995884 (7) contain the supplementary
crystallographic data for this paper. These data can be obtained
free of charge from The Cambridge Crystallographic Data Centre
HypoGel resin–ligand loading
HypoGel resin (amine acylated with succinic acid, loading:
0.9 mmolgꢀ1, 0.203 g, 0.18 mmol) was swelled in 8 mL DMF. After
1 hour the solvent was removed by filtration. Compound 11
(0.200 g, 0.36 mmol), EDCI·HCl (0.041 g, 0.216 mmol), HOBt
(0.033 g, 0.216 mmol) and triethylamine (0.062 mL, 0.45 mmol)
were dissolved in DMF (8 mL) and this solution was shaken with
the swollen resin at room temperature for 48 h. Ligand uptake was
monitored by HPLC analysis. After 48 h the reaction solution was
removed by filtration. The resin was washed once with 2 mL DMF
and then with excess DCM, DMF, MeOH and Et2O, before being
dried under vacuum until the weight no longer changed (0.233 g,
0.25 mmolgꢀ1 loading, 33%).
HypoGel resin–zinc loading
HypoGel resin loaded with 11 (loading: 0.25 mmolgꢀ1, 0.223 g,
0.059 mmol 11) was shaken in 10 mm HEPES buffer at pH 7 (5 mL)
for 30 min to allow the resin to swell. After the buffer was removed
by filtration, the resin was shaken in a HEPES-buffered solution
containing Zn(NO3)2·6H2O (0.073 g, 0.24 mmol) at room tempera-
ture for 24 h. After this time the solution was removed by filtration,
and the resin was washed 3 times with 3 mL of buffer (30 min
each). The resin was then swollen in buffer again, and this loading
and washing cycle was repeated twice more. After the final buffer
wash, the resin was rinsed with Milli-Q water, methanol and diethyl
ether and finally dried under vacuum. The zinc concentration in
each of the starting and final solutions, as well as in the 3 buffer
washes, was quantified using UV/Vis spectroscopy in conjunction
with a colorimetric zinc indicator (PV). These concentration values
were used to determine the amount of zinc taken up by the resin.
Zn content=0.46 mmolgꢀ1 (91% sites filled).
1,3-Bis(bis(pyridin-2-ylmethyl)amino)propan-2-olbis-nickel(-
II)hexafluorophosphatediacetate (5)
1,3-Bis(bis(pyridin-2-ylmethyl)amino)propan-2-ol
(0.036 g,
0.08 mmol) was stirred in methanol (5 mL) at 558C. Triethylamine
(0.012 mL, 0.08 mmol) was added and the hot solution was stirred
for 10 min. Nickel acetate hydrate (0.032 g, 0.16 mmol) was then
added and the temperature was raised to 678C. Sodium hexafluor-
ophosphate (0.027 g, 0.16 mmol) was then added and the mixture
heated at reflux for 30 min. The solution was then allowed to cool
to room temperature and placed in the freezer (ꢀ188C) for 2
weeks. After this time, pink crystals had formed, which were re-
moved by filtration. The mother liquor was then decanted and
concentrated under nitrogen. This methanolic solution was then
placed in the fridge, and after slow diffusion of diethyl ether the
di-nickel product 5 was obtained as large deep-blue crystals suita-
Chem. Eur. J. 2014, 20, 17168 – 17177
17175
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