Gang Min Lee and S.W. Lee
Polyhedron 202 (2021) 115229
Table 1
tered and then concentrated by slow evaporation. The crystals
formed were filtered, washed with dichloromethane (2 ꢂ 2 mL)
and air-dried to give brown crystals of compound 1 (0.0075 g,
0.0064 mmol, yield: 64%). IR (KBr, cmꢁ1): 638, 693, 746, 789,
832, 923, 972, 1029 (msSO3), 1102, 1154 (msCF), 1254 (masCF),
1432, 1616 (C@N). Anal Calcd for C51H42F6N4O7P2PdS2: C, 52.38;
X-ray data collection and structure refinement.
Compound 1ꢀ(H2O)
C51H42F6N4O7P2PdS2
1169.34
223(2)
monoclinic
P21/n
Empirical formula
Formula weight
Temperature (K)
Crystal system
Space group
a (Å)
H, 3.62; N, 4.79. Found: C, 53.02; H, 4.12; N, 4.52%.
13.276(3)
23.777(5)
21.451(4)
90
b (Å)
c (Å)
2.3. Microwave-assisted optimization of the Sonogashira cross-
coupling reaction of iodobenzene with phenylacetylene
a
(°)
b (°)
105.92(3)
90
6512(2)
4
1.193
0.459
A
mixture of iodobenzene (1.0 mmol), phenylacetylene
c
(°)
V (Å3)
(1.0 mmol), TEA (triethylamine, 1.2 mmol), compound 1 (5 mol
%), copper(I) iodide (7 mol%) and H2O (5 mL) in a 10 mL microwave
reaction vial was heated under microwave conditions (40, 60, 80
and 100 °C) in air for an appropriate time. After the mixture was
cooled to room temperature, the crude product was extracted with
ether (3 ꢂ 10 mL), the combined organic phases were dried over
sodium sulfate and then concentrated by rotary evaporation. The
desired product was isolated by silica gel column chromatography.
Z
q
l
(g cmꢁ3
(mmꢁ1
)
)
F(000)
No. of reflections collected
No. of independent reflections
No. of reflections with I > 2
Tmaximum
Tminimum
2376
188,371
16,248
9774
0.7457
0.6178
658
r(I)
No. of parameters
Goodness-of-fit on F2
R1a
1.029
2.4. Microwave-assisted Sonogashira cross-coupling reaction of aryl
halides with phenylacetylene
0.0643
0.1639
2.583
ꢁ1.069
wR2b
Maximum in
Minimum in
D
q
(e Åꢁ3
(e Åꢁ3
)
)
D
q
A
mixture of the aryl halide (1 mmol), phenylacetylene
a
(1 mmol), copper(I) iodide (7 mol%), compound 1 (5 mol%), TEA
(1.2 mmol) and H2O (5 mL) in a microwave reaction vial was
heated under microwave conditions in air at 100 °C for 2 h and
then cooled to room temperature. The crude product was purified
by column chromatography. All coupled products were treated by
a similar workup (for the NMR spectra and melting points of the
products, see the supporting information).
R1 =
R
[|Fo| – |Fc|]/
R
|Fo|], bwR2 = {
R
[w(F2o ꢁ F2c)2]/
R
[w(F2o)2]}1/2
parison, the IR spectrum of the ligand shows a C@N bond stretch at
1625 cmꢁ1 [27].
Fig. 1 shows the asymmetric unit of compound 1, which con-
sists of a Pd2+ ion, a 4,40-bipyridine-type ligand (L), a dppp ligand,
an aqua ligand (a lattice water), as well as two triflate counterions.
The local coordination environment around the central Pd atom is
presented in Fig. 2, in which the Pd metal is 4-coordinated. The Pd
(dppp) units are linked by the L ligands in the [010] direction to
form a one-dimensional zigzag chain (Fig. 3). As discussed in the
introduction, crystal structures of the Pd CPs and MOFs are cur-
rently limited and only a few structures have been reported. Pud-
dephatt and coworkers reported the 1D structures of trans-
[PdCl2(3-NC5H4COOH)2], trans-[PdCl2(4-NC5H4COOH)2] and trans-
[PdCl2(2-Ph-NC9H5COOH)2] [16]. In addition, Jain’s group reported
the 1D structure of [Pd2(SeCH2CH2CH2NMe2)2(CH3COO)](OTf) [17].
A third example, which closely resembles our compound (1), is a
1D zigzag chain reported by Sara and coworkers [18].
2.5. X-ray structure determination
X-ray data for compound 1 was collected with a Bruker Smart
APEX2 diffractometer (Madison, WI, USA) equipped with a Mo X-
ray tube at the Korea Basic Science Institute (KBSI). The reflection
data were absorption-corrected with SADABS based upon the Laue
symmetry by using equivalent reflections [30]. All calculations
were carried out with SHELXTL programs [31].
A
brown crystal of 1ꢀ(H2O) of approximate dimensions
0.20 ꢂ 0.17 ꢂ 0.13 mm, shaped as a block, was used for crystal
and intensity data collection. The structure was solved by direct
methods. All non-hydrogen atoms were refined anisotropically.
All hydrogen atoms were generated in idealized positions and
refined in a riding model, except those in the lattice water mole-
cules, which could not be located. Details of the crystal data, inten-
sity collection and refinement details are given in Table 1. Selected
bond lengths and angles are shown in Table 2.
3.2. Microwave-assisted optimization for the Sonogashira cross-
coupling reaction
To determine the optimum conditions, we performed the cou-
pling reactions of iodobenzene with phenylacetylene under aero-
bic conditions. Under the conditions in which the product is
diphenylacetylene, the solvent was water, the amount of catalyst
(compound 1) was 5 mol% and the reaction time was 2 h, whilst
the reactions were carried out at various temperatures (40–
100 °C, Scheme 2). The results (entries 1–4 in Table 3) revealed that
the yield increases with increasing temperature and the highest
yield (60%) was obtained at 100 °C. Consequently, subsequent reac-
tions were performed at this temperature. Next, we performed the
reactions for various reaction times (0.5–10 h) and found the opti-
mum time to be 2 h (entries 5–15 in Table 3). Finally, the reactions
were carried out at 100 °C for 2 h using various catalyst concentra-
tions (1–10 mol%) and the optimum catalyst concentration was
found to be 5 mol% (entries 16–25 in Table 3). Hence, from entries
1–25 in Table 3, the optimum reaction conditions can be summa-
3. Results and discussion
3.1. Synthesis and structure of the Pd coordination polymer (1)
The one-dimensional palladium coordination polymer [Pd
(dppp)(L)](OTf)2ꢀ(H2O) (1) was prepared from a 4,40-bipyridine-
type ligand (L) and [Pd(dppp)(OTf)2] in dichloromethane
(Scheme 1). The product was characterized by IR and X-ray crystal-
lography. Compound 1 is insoluble in common organic solvents,
such as dichloromethane, acetonitrile, toluene and acetone. The
IR spectrum of compound
1 displays a C@N stretch at
1616 cmꢁ1, a CF3 asymmetric stretch at 1254 cmꢁ1, a CF3 symmet-
ric stretch at 1154 cmꢁ1, and an SO3 band at 1029 cmꢁ1. As a com-
2