Inorganic Chemistry
Article
Table 1. Overview of the Optimized Synthesis Conditions for 1 ([Ni(H DPBP) (H O) ]), 2 ([Co(H DPBP) (H O) ]), CAU-
3
2
2
4
3
2
2
4
4
6 ([Ni (H TPPE)(H O) ]·4H O), CAU-47 ([Co (H TPPE)(H O) ]·3H O), and Co-CAU-48 ([Co (H TPPE)]·6H O) and
2 4 2 6 2 2 4 2 4 2 2 4 2
a
Results of the Elemental Analyses
elemental anal. calcd/found (%)
compound
M [mL]
L [mg]
H O [mL]
2
reactor size [mL]
yield [%]
C
H
N
1
2
0.054
0.054
0.27
0.27
5.4
11.7
11.7
58.7
58.7
1174
0.146
0.146
0.73
0.73
14.6
0.25
0.25
2
2
30
∼3
∼3
15.3
7.1
b
b
b
b
b
b
CAU-46
CAU-47
Co-CAU-48
32.47/34.96
34.68/35.11
35.55/37.79
5.07/3.4
4.7/3.5
4.13/3.43
0/0.18
0/0.06
0/0.09
11.8
a
The yields are based on the amount of linker employed in the reaction. M corresponds to the aqueous metal nitrate solution (c = 1 mol/L) and L
b
to the linker (introduced as powder). CHN values could not be determined due to small amounts of samples.
2
4
For the sorption measurements, the samples were activated for 16 h
a filling volume of 1 mL as described previously. The effect of molar
ratios, reactant concentration, temperature−time-program, and
various counterions of the metal salts was investigated. A complete
at elevated temperatures (between 80 and 120 °C) under reduced
pressure (<10− kPa). The H O sorption experiments were carried
2
2
out at 298 K and the N sorption experiments at 77 K. The integrity
2
of the sample after the sorption experiment was confirmed by PXRD
measurements. For CAU-46 and CAU-47, an activation temperature
of 80 °C was chosen, while for M-CAU-48 (M = Ni, Co) activation
temperatures of 120 °C were used.
Optimized Reaction Parameters of the Title Compounds.
The linker was introduced into the Teflon inserts as a powder.
Subsequently, water and the aqueous metal nitrate solution (c = 1
mol/L) were added. The reactor was sealed and heated using a
temperature program involving a constant temperature ramp for 6 h
to 180 °C, held at this temperature for 48 h, and gradually cooled over
6 h. After filtration, the microcrystalline powders of CAU-46, CAU-47
and Co-CAU-48 were stirred in 10 mL of water and subsequently in
MeOH for 24 h to remove trace impurities of 1 or 2, respectively,
after which they were filtered off and dried at room temperature. In
Table 1, exact amounts and yields are given.
Synthetic Procedures. Synthesis of 1,1,2,2-Tetrakis[4-
phosphonophenyl]ethylene (H TPPE). The three-step synthesis of
8
the new tetraphosphonic acid H TPPE is shown in Figure 2. The first
8
step is the bromination of tetraphenylethylene, and it is carried out
21
following the procedure described by Vyas et al., which was first
2
2
published by Buckles et al. in 1950. For the synthesis of
tetrabromophenylethylene, liquid bromine (11.58 mL, 217.16
mmol) is introduced into the lower part of a desiccator. Tetraphenyl-
ethylene (10.3 g, 31.02 mmol) is placed onto the rack above it, and
the desiccator lid is closed. After 5 days at room temperature, the
desiccator is opened, and the resulting red-brownish powder is
recrystallized from a dichloromethane−methanol mixture (2:1) to
yield white needles of tetrabromophenylethylene (15.81 g, 24 mmol,
Crystal Structure Determination and Topological Analysis.
enough for single-crystal X-ray diffraction (SCXRD) (Figure S2). The
25
crystal structures were solved using the program SHELXT and
26
refined with SHELXL. In the data set of 1, H-atoms could be
unequivocally located from the Fourier map, and their positions were
freely refined. However, in the data set of 2, only H-atoms attached to
the aromatic rings could be localized and freely refined. The
remaining protons were added via AFIX instructions and refined
using a riding model.
7
8% yield).
The second step, the substitution of bromine by diethyl
phosphonate, is a Michaelis−Arbuzov reaction. This procedure, first
23
described by Tavs et al., was adapted with modified stoichiometry.
Tetrabromophenylethylene (12 g, 18.5 mmol) and oven-dried (120
Due to the microcrystalline morphology of CAU-46, -47, and -48,
their structures were determined by a combination of electron
CAU-46 and CAU-47 were refined against PXRD data employing the
Rietveld method. However, for M-CAU-48, only a structure model
elucidated from electron diffraction from a Co-CAU-48 sample can be
presented since the Rietveld refinement did not converge to a
chemically sensible structure. This is probably due to a large unit cell
and the complexity of the triclinic crystal structure. Nevertheless, a
very good agreement between measured and simulated PXRD
°
C, 3 h) NiCl (2.28g, 17.57 mmol) were introduced into 420 mL of
2
1
,3-diisopropylbenzene, which was degassed for 30 min by bubbling
N2 through the solvent. The mixture, under N -atmosphere, was
2
heated to 170 °C, and triethyl phosphite (22.01 mL, 138.75 mmol)
was added dropwise within 1 h under stirring. The reaction mixture
was stirred for an additional 24 h at 170 °C, and after the reaction was
cooled to room temperature, the solvent was removed under reduced
pressure. The resulting black residue was dissolved in 200 mL of
dichloromethane and 100 mL of water, and the organic phase was
washed five times with water (100 mL). The organic phase was
separated, and the solvent was removed under reduced pressure.
Tetra(diethylphosphono)phenylethylene is obtained as a white solid
(
12.46 g, 15.8 mmol, 85% yield).
The linker molecule H TPPE was obtained by stirring of
27
8
All topological analyses were carried out using ToposPro, as well
tetra(diethylphosphono)phenylethylene in 250 mL of concentrated
HCl for 3 days under reflux. The resulting precipitate was filtered,
stirred for 24 h in dichloromethane, filtered again, and dried under
ambient conditions. Tetraphosphonophenylethylene is obtained as a
white powder (6.82 g, 10.45 mmol, 56% yield based on
tetrabromophenylethylene).
Synthesis of the Title Compounds. Three different reactor sizes
were employed for the discovery, synthesis optimization, and scale-up
of the metal phosphonates.
28,29
as Systre and 3dt (both part of the Gavrog package).
RESULTS AND DISCUSSION
■
Synthesis. The new tetraphosphonic acid H TPPE was
8
synthesized in a three-step reaction (Figure 2). The
bromination at room temperature in a desiccator and the
workup procedure can easily be carried out at a larger scale,
and recrystallization of the raw product always led to white,
product as confirmed via NMR spectroscopy (Figure S13).
Although the hydrolysis of the ester is carried out using boiling
concentrated hydrochloric acid, no hydrochlorination of the
Discovery of the Title Compounds. High-throughput (HT)
2
+
2+
2+
investigations of the systems M /H TPPE/H O with M = Co
8
2
and Ni2+ were carried out using a custom-made 48-multiclave and
Teflon inserts with a total volume of 250 μL and a filling volume of
2
00 μL or a 24-multiclave and inserts with a total volume of 2 mL and
C
Inorg. Chem. XXXX, XXX, XXX−XXX