Four rare structurally characterized hetero-pentanuclear [Zn4Ln] bis(salamo)-type complexes: Syntheses, crystal structures and spectroscopic properties

Article abstract of DOI:10.1039/c9ra07423f

Four new hetero-pentanuclear 3d-4f complexes [Zn₄(L)₂La(NO₃)₂(OEt)(H₂O)] (1), [Zn₄(L)₂Ce(NO₃)₂(OMe)(MeOH)] (2), [Zn₄(L)₂Pr(NO₃

Full text of DOI:10.1039/c9ra07423f

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Four rare structurally characterized hetero-
pentanuclear [Zn4Ln] bis(salamo)-type complexes:
Cite this: RSC Adv., 2019, 9, 37331
syntheses, crystal structures and spectroscopic
properties†
Lu-Mei Pu, Lan Wang,b Xiao-Yan Li,b Yin-Xia Sun,b Quan-Peng Kang,b
a
*
a
b
Hai-Tao Long,a Wei-Bing Xu
and Wen-Kui Dong
*
Four new hetero-pentanuclear 3d–4f complexes [Zn4(L)2La(NO3)2(OEt)(H2O)] (1), [Zn4(L)2Ce(NO3)2-
(OMe)(MeOH)] (2), [Zn4(L)2Pr(NO3)2(OEt)(EtOH)] (3) and [Zn4(L)2Nd(NO3)2(OMe)(MeOH)] (4) were
synthesized by the reactions of a newly synthesized octadentate bis(salamo)-based tetraoxime ligand (H4L)
with Zn(OAc)2$2H2O and Ln(NO3)3$6H2O (Ln ¼ La, Ce, Pr and Nd), respectively, and characterized via
elemental analyses, FT-IR, UV-Vis spectroscopy and single crystal X-ray crystallography. The X-ray
crystallographic investigation revealed that all ZnII ions were located in N2O3 coordination spheres, and
possessed a trigonal bipyramid coordination environment. The LnIII ion lay in an O8 coordination sphere,
and adopted a distorted square antiprismatic coordination environment. Furthermore, supramolecular
interactions and fluorescence properties were investigated.
Received 15th September 2019
Accepted 6th November 2019
DOI: 10.1039/c9ra07423f
rsc.li/rsc-advances
characterized. Meanwhile, the luminescence properties of
complexes 1–4 were studied.
1 Introduction
Salen-type ligands and their analogues are very versatile chelating
ligands in inorganic and organometallic chemistry.1 Their
complexes have considerable intrinsic value due to their wide
applications in electrochemistry,2 building supramolecular struc-
tures,3 catalysis elds,4 magnetism,5 biological elds6 and so forth.
In recent years, a preferable class of salen-type compounds
(salamo: (R–CH]N–O–(CH2)n–O–N]CH–R)) has been re-
ported,7 and the large electronegativity of O atoms is expected to
lead to different and novel structures and properties of the
resulting complexes. The 3d–4f complexes have attracted much
attention due to the visible and near-infrared luminescence
produced by lanthanide f–f transitions.8 Luminescence appli-
cations of lanthanides are a consequence of their narrow
emission bands, large Stokes shis, negligible environmental
inuences and relatively long luminescence lifetimes. However,
3d–4f complexes with salamo-like ligands have been rarely
reported.9
2 Experimental
2.1. Materials and methods
1,2-Dimethoxybenzene, 1,2-dibromoethane, TMEDA, n-butyl-
lithium, boron tribromide and 2-hydroxy-1-naphthaldehyde
(99%) were purchased from Alfa Aesar and used without
further purication. Other reagents and solvents were
analytical grade reagents from Tianjin Chemical Reagent
Factory.
Elemental analyses for carbon, hydrogen and nitrogen
were obtained using a GmbH VariuoEL V3.00 automatic
elemental analysis instrument (Berlin, Germany). LaIII, CeIII
,
PrIII and NdIII were gained using an IRIS ER/S-WP-1 ICP
atomic emission spectrometer (Berlin, Germany). Melting
points were obtained via a microscopic melting point appa-
ratus made by Beijing Taike Instrument Company Limited.
IR spectra (4000–400 cmꢀ1) were determined via a Vertex 70
FT-IR spectrophotometer (Bruker, Billerica, MA, USA), with
samples prepared as KBr pellets. UV-Vis absorption spectra
were determined using a Shimadzu UV-3900 spectrometer
(Shimadzu, Japan). 1H NMR spectra were determined via
German Bruker AVANCE DRX-400/600 spectroscopy. X-ray
single crystal structure determinations for complexes 1, 2, 3
and 4 were carried out on a Bruker APEX-II CCD diffractom-
eter. Fluorescence spectra were recorded on an F-7000 FL
Herein, a series of rare heteropentanuclear [Zn4Ln] (Ln ¼ La,
Ce, Pr and Nd) complexes containing octadentate bis(salamo)-
based tetraoxime ligand H4L were synthesized and structurally
aCollege of Science, Gansu Agricultural University, Lanzhou, Gansu 730070, P. R.
China. E-mail: pulm@gsau.edu.cn
bCollege of Chemical and Biological Engineering, Lanzhou Jiaotong University,
Lanzhou, Gansu, 730070, P. R. China. E-mail: dongwk@126.com
† Electronic supplementary information (ESI) available. CCDC 1894560, 1894557,
1894559 and 1894558 for complexes 1–4. For ESI and crystallographic data in CIF
or other electronic format see DOI: 10.1039/c9ra07423f
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Scheme 1 Synthetic route to H4L.
Scheme 2 Synthetic routes to H4L and its complexes 1–4.
spectrophotometer. Near infrared (NIR) spectra were deter-
mined through PTI QM4 spectrouorometer with a PTI QM4
Near infrared InGaAs detector.
2.2. Synthesis of the H4L
The reaction steps of the ligand (H4L) can be seen from Scheme
1. 1,2-Bis(aminooxy)ethane, 2,3-dihydroxybenzene-1,4-dicarbal-
Fig. 1 IR spectra of H4L and its corresponding complexes 1–4.
37332 | RSC Adv., 2019, 9, 37331–37343
Fig. 2 UV-Vis spectra of the free ligand H4L and its complexes 1–4.
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Table 1 Crystal data and the structure refinements for complexes 1–4
Complex
1
2
3
4
Empirical formula
Formula weight
T (K)
C
70H59LaZn4N10O24
C70H59CeZn4N10O24
1824.86
173(2)
0.71073
Monoclinic
C2/c
16.9226(7)
23.3361(10)
24.4208(13)
90
109.4290(10)
90
C72H63PrZn4N10O24
1854.71
173(2)
0.71073
Monoclinic
C2/c
16.7809(7)
23.4499(7)
24.1484(11)
90
108.736(5)
90
C70H59NdZn4N10O24
1829.99
173(2)
0.71073
Monoclinic
C2/c
16.9226(7)
23.3361(10)
24.4208(13)
90
109.4290(10)
90
1824.66
296(2)
0.71073
Monoclinic
C2/c
23.8927(11)
15.5212(7)
45.813(2)
90
97.7300(10)
90
˚
Wavelength (A)
Crystal system
Space group
˚
a (A)
˚
b (A)
˚
c (A)
a (ꢁ)
b (ꢁ)
g (ꢁ)
3
˚
V (A )
16 835.2(13)
8
1.440
9094.8(7)
4
1.333
8999.1(7)
4
1.369
9094.8(7)
4
1.336
Z
Dcalc. (g cmꢀ3
)
Absorption
1.694
1.599
1.653
1.669
coefficient (mmꢀ1
F (000)
)
7344
3672
3744
3684
Crystal size (mm)
0.270 ꢂ 0.250 ꢂ 0.220
0.220 ꢂ 0.190 ꢂ 0.160
0.220 ꢂ 0.200 ꢂ 0.180
0.220 ꢂ 0.190 ꢂ 0.160
q Range (ꢁ)
2.044–25.010
2.485–25.008
1.548–26.000
2.485–25.008
Index ranges
ꢀ25 # h # 28
ꢀ20 # h # 20
ꢀ22 # k # 27
ꢀ20 # h # 20
ꢀ27 # k # 28
ꢀ20 # h # 17
ꢀ27 # k # 27
ꢀ18 # k # 18
ꢀ51 # l # 54
ꢀ29 # l # 29
ꢀ29 # l # 29
ꢀ29 # l # 28
Reections
collected/unique
59 539/14 818 [Rint ¼ 0.0347]
32 276/7999 [Rint ¼ 0.0371]
19 902/8832 [Rint ¼ 0.0179]
32 970/8002 [Rint ¼ 0.0391]
Completeness to q
Data/restraints/
parameters
99.8% (q ¼ 25.010)
99.8% (q ¼ 25.008)
99.7% (q ¼ 25.242)
99.8% (q ¼ 25.008)
14 818/0/1009
7999/0/493
8832/5/496
8002/6/487
GOF
0.963
1.049
1.043
1.030
Final R1, wR2 indices
R1, wR2 indices
(all data)
0.0399, 0.1006
0.0454, 0.1044
0.0363, 0.1003
0.0448, 0.1059
0.0315, 0.0971
0.0412, 0.1007
0.0377, 0.0974
0.0465, 0.1020
Largest diff. peak
1.492 and ꢀ1.009
1.563 and ꢀ0.981
1.048 and ꢀ0.805
1.814 and ꢀ0.783
ꢀ3
˚
and hole (e A
)
dehyde and 2-[O-(1-ethyloxyamide)]oxime-2-naphthol were constant magnetic stirring, and an ethanol solution (3 mL) of
prepared according to analogous methods reported earlier.10
La(NO3)3$6H2O (4.33 mg, 0.015 mmol) was then added. The
An ethanol solution (10 mL) of 2,3-dihydroxybenzene-1,4- mixed solution was stirred for 15 minutes at room temperature
dicarbaldehyde (166.2 mg, 1.0 mmol) was added to an ethanol and then ltered off, and the ltrate was transferred to a cillin
solution (20 mL) of 2-[O-(1-ethyloxyamide)]oxime-2-naphthol bottle. Sealed the opening of the bottle with tinfoil and let it
(492.6 mg, 2 mmol). The mixed solution was stirred at 55 ꢁC stand for two weeks, some block-like crystals suitable for X-ray
for 8 h, cooling to room temperature, the precipitate was ltered diffraction were formed.
and washed with n-hexane to obtain a yellow powder. Yield:
Complex 1, yellow block-like crystals. Yield: 52%.
ꢁ
87%. mp.: 198–200 C. Anal. calc. for C34H30N4O8: C, 65.59; H, Elemental analysis: anal. calc. for [Zn4(L)2La(NO3)2(OEt)
4.86; N, 9.00%. Found: C, 65.65; H, 4.94; N, 8.92%. 1H NMR (400 (H2O)] (C70H59LaZn4N10O24) (%): C, 46.08; H, 3.26; N, 7.68; Zn,
MHz, CDCl3) d 10.82 (s, 2H), 9.70 (s, 2H), 9.17 (s, 2H), 8.25 (d, J ¼ 14.33; La, 7.61. Found (%): C, 46.19; H, 3.38; N, 7.53; Zn, 14.41;
2.5 Hz, 2H), 7.96 (d, J ¼ 8.7 Hz, 2H), 7.80–7.72 (m, 4H), 7.50 (t, J La, 7.48.
¼ 7.7 Hz, 2H), 7.35 (t, J ¼ 7.5 Hz, 2H), 7.20 (d, J ¼ 9.0 Hz, 2H),
Complex 2, yellow block-like crystals. Yield: 62%. Elemental
analysis: anal. calc. for [Zn4(L)2Ce(NO3)2(OMe)(MeOH)] (C70-
H59CeZn4N10O24) (%): C, 46.05; H, 3.26; N, 7.67; Zn, 14.32; Ce,
7.67. Found (%): C, 46.12; H, 3.37; N, 7.56; Zn, 14.39; Ce, 7.81.
Complex 3, yellow block-like crystals. Yield: 69%. Elemental
6.75 (s, 2H), 4.56 (s, 8H).
2.3. General procedure for the preparation of complexes 1–4
The synthesis methods of complexes 2–4 are similar to that of
analysis: anal. calc. for [Zn4(L)2Pr(NO3)2(OEt)(EtOH)] (C72H63
-
complex
1 (Scheme 2). An ethanol solution (3 mL) of
PrZn4N10O24) (%): C, 46.62; H, 3.42; N, 7.55; Zn, 14.10; Pr, 7.60.
Found (%): C, 46.79; H, 3.48; N, 7.50; Zn, 14.15; Pr, 7.68.
Zn(OAc)2$2H2O (13.155 mg, 0.065 mmol) was added to a chlo-
roform solution (5 mL) of H4L (18.675 mg, 0.03 mmol) under
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Fig. 3 (a) Molecule structure of complex 1 ([Zn4(L)2La(NO3)2(OEt)(H2O)]) (hydrogen atoms and solvent molecules are omitted for clarity). (b)
Coordination polyhedrons for ZnII and LaIII ions of complex 1.
Complex 4, yellow block-like crystals. Yield: 64%.
Elemental analysis: anal. calc. for [Zn4(L)2Nd(NO3)2(OMe)
(MeOH)] (C70H59NdZn4N10O24) (%): C, 45.94; H, 3.25; N, 7.65;
Zn, 14.29; Nd, 7.88. Found (%): C, 46.09; H, 3.38; N, 7.53; Zn,
14.38; Nd, 7.96.
2.4. X-ray crystallographic analysis
Crystal data for complexes 1–4 were collected on a Bruker APEX-
˚
II CCD area detector with Mo Ka radiation (l ¼ 0.71073 A) at
296(2), 173(2), 173(2) and 173(2) K. respectively. Reection data
were corrected for LP factors semi-empirical absorption were
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Table 2 Selected bond lengths (A˚) and angles (ꢁ) for complexes 1–4a
Complex 1
Bond
Lengths
Bond
Lengths
Bond
Lengths
Zn1–O19
Zn2–O1
Zn2–O24
Zn3–O7
Zn4–O14
Zn2–N2
Zn3–N5
La1–O5
La1–O20
La1–O1
2.001(3)
2.051(2)
2.014(3)
2.081(2)
2.059(3)
2.011(3)
2.019(3)
2.491(2)
2.496(3)
2.534(3)
Zn1–O20
Zn2–O4
Zn3–O5
Zn4–O12
Zn1–N3
Zn2–N6
Zn4–N7
La1–O12
La1–O4
La1–O13
2.085(3)
1.957(2)
1.975(2)
1.999(3)
2.149(3)
2.108(3)
2.038(4)
2.497(2)
2.505(2)
2.537(3)
Zn1–O22
Zn1–O22#1
Zn3–O6
Zn4–O13
Zn1–N4
Zn3–N1
Zn4–N8
La1–O19
La1–O7
2.054(6)
2.019(14)
1.983(3)
2.057(3)
2.048(3)
2.127(3)
2.120(3)
2.500(2)
2.514(2)
Complex 1
Bond
Angles
Bond
Angles
Bond
Angles
O19–Zn1–O22
O19–Zn1–O22#1
O22#1–Zn1–O20
O19–Zn1–N3
O22–Zn1–N3
O4–Zn2–O24
N2–Zn2–O1
N2–Zn2–N6
O5–Zn3–O6
O5–Zn3–O7
O5–Zn3–N1
O7–Zn3–N1
N7–Zn4–O13
O13–Zn4–O14
O13–Zn4–N8
O5–La1–O20
O5–La1–O19
O5–La1–O4
109.0(2)
134.0(5)
105.3(4)
N4–Zn1–O22
O19–Zn1–N4
N4–Zn1–O20
O22#1–Zn1–N3
O20–Zn1–N3
N2–Zn2–O24
O24–Zn2–O1
O24–Zn2–N6
O5–Zn3–N5
O6–Zn3–O7
O6–Zn3–N1
O12–Zn4–N7
O12–Zn4–O14
O12–Zn4–N8
O14–Zn4–N8
O5–La1–O12
O20–La1–O19
O20–La1–O4
O5–La1–O7
123.2(2)
O19–Zn1–O20
O22#1–Zn1–N4
O22–Zn1–O20
N4–Zn1–N3
O4–Zn2–N2
O4–Zn2–O1
O4–Zn2–N6
O1–Zn2–N6
O6–Zn3–N5
N5–Zn3–O7
N5–Zn3–N1
O12–Zn4–O13
N7–Zn4–O14
N7–Zn4–N8
81.62(10)
101.9(4)
124.08(12)
83.62(11)
89.3(4)
85.79(17)
95.80(14)
129.50(12)
83.74(10)
89.59(11)
171.90(12)
117.44(14)
84.77(11)
97.33(13)
82.80(10)
130.82(13)
96.06(14)
86.56(12)
106.58(18)
109.62(13)
85.55(11)
95.24(12)
113.02(12)
83.24(10)
87.25(11)
169.29(12)
84.94(12)
94.37(12)
169.00(13)
91.87(9)
148.96(9)
62.34(8)
126.01(8)
81.51(8)
124.73(8)
77.66(8)
77.97(8)
165.20(13)
120.27(14)
93.95(12)
92.61(13)
128.10(12)
90.74(12)
97.52(14)
124.57(13)
103.94(11)
87.66(12)
93.24(14)
129.19(8)
64.64(8)
78.16(8)
65.16(8)
93.10(8)
90.06(9)
64.15(8)
169.01(8)
93.23(9)
O20–La1–O12
O12–La1–O19
O12–La1–O4
O20–La1–O7
O4–La1–O7
O12–La1–O1
O7–La1–O1
O12–La1–O13
O7–La1–O13
126.29(8)
63.26(8)
146.66(8)
89.17(9)
125.23(8)
91.02(8)
170.10(8)
64.41(8)
90.31(9)
O19–La1–O4
O12–La1–O7
O5–La1–O1
O19–La1–O1
O5–La1–O13
O19–La1–O13
O1–La1–O13
O19–La1–O7
O20–La1–O1
O4–La1–O1
O20–La1–O13
O4–La1–O13
126.35(8)
92.31(9)
Complex 2
Bond
Lengths
Bond
Lengths
Bond
Lengths
O12–Zn1
O9–Zn2
N4–Zn2
N1–Zn1
Ce1–O3
Ce1–O3#2
Ce1–O10
2.020(3)
2.026(3)
2.015(3)
2.019(3)
2.475(2)
2.475(2)
2.475(2)
O11–Zn1
O4–Zn2
N3–Zn2
2.043(2)
1.985(2)
2.137(3)
O10–Zn2
O3–Zn1
N2–Zn1
2.068(2)
1.972(2)
2.110(3)
Ce1–O10#2
Ce1–O4#2
Ce1–O4
2.475(2)
2.479(2)
2.479(2)
Ce1–O11#2
Ce1–O11
2.511(2)
2.511(2)
Complex 2
Bond
Angles
Bond
Angles
Bond
Angles
O3–Zn1–O12
O3–Zn1–O11
O3–Zn1–N2
O11–Zn1–N2
N4–Zn2–O9
113.98(12)
81.90(10)
88.94(11)
169.37(12)
127.60(13)
O3–Zn1–N1
O12–Zn1–O11
O12–Zn1–N2
O4–Zn2–N4
O4–Zn2–O10
127.13(12)
93.03(11)
95.64(12)
122.97(12)
82.84(9)
O12–Zn1–N1
N1–Zn1–O11
N1–Zn1–N2
O4–Zn2–O9
N4–Zn2–O10
117.85(14)
85.67(12)
95.67(13)
109.03(11)
84.60(11)
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Table 2 (Contd.)
Complex 2
Bond
Angles
Bond
Angles
Bond
Angles
O9–Zn2–O10
O9–Zn2–N3
96.52(12)
93.18(14)
126.22(11)
127.67(8)
146.35(8)
63.21(8)
78.78(8)
65.57(8)
63.21(8)
146.35(8)
65.57(8)
78.78(8)
O4–Zn2–N3
87.24(11)
167.93(12)
92.34(8)
92.34(8)
130.09(11)
80.04(8)
63.72(8)
90.07(8)
168.48(8)
125.03(8)
90.03(8)
N4–Zn2–N3
95.14(13)
O10–Zn2–N3
O3–Ce1–O3#2
O3–Ce1–O10
O3–Ce1–O4#2
O3#2–Ce1–O4#2
O10–Ce1–O4#2
O10#2–Ce1–O4#2
O3–Ce1–O4
O3#2–Ce1–O10
O3–Ce1–O10#2
O4#2–Ce1–O4
O3#2–Ce1–O10#2
O10–Ce1–O10#2
O3–Ce1–O11
127.67(8)
87.78(12)
63.72(8)
80.03(8)
168.47(8)
90.07(8)
90.02(8)
125.03(8)
94.20(11)
O3–Ce1–O11#2
O3#2–Ce1–O11#2
O10–Ce1–O11#2
O10#2–Ce1–O11#2
O4#2–Ce1–O11#2
O4–Ce1–O11#2
O3#2–Ce1–O11
O10–Ce1–O11
O10#2–Ce1–O11
O4#2–Ce1–O11
O4–Ce1–O11
O3#2–Ce1–O4
O10–Ce1–O4
O10#2–Ce1–O4
O11#2–Ce1–O11
Complex 3
Bond
Lengths
Bond
Lengths
Bond
Lengths
N1–Zn1
N4–Zn2
O8–Zn2
O1–Pr1
O4–Pr1
O5–Pr1
2.015(2)
2.018(3)
2.0372(19)
2.4646(19)
2.4605(19)
2.4471(19)
N2–Zn1
O1–Zn1
O12–Zn2
O8–Pr1
2.143(3)
2.0699(19)
2.015(2)
2.5097(19)
2.4646(19)
2.4605(19)
N3–Zn2
O5–Zn2
2.110(3)
1.9785(19)
O5#3–Pr1
O8#3–Pr1
2.4471(19)
2.5097(19)
O1#3–Pr1
O4#3–Pr1
Complex 3
Bond
Angles
Bond
Angles
Bond
Angles
O4–Zn1–N1
O4–Zn1–O1
O4–Zn1–N2
O1–Zn1–N2
O12–Zn2–N4
N4–Zn2–O8
N4–Zn2–N3
O5#3–Pr1–O5
O5#3–Pr1–O4
O5–Pr1–O4
O5#3–Pr1–O4#3
O5–Pr1–O4#3
O4–Pr1–O4#3
O5#3–Pr1–O1
O5–Pr1–O1
O4–Pr1–O1
O4#3–Pr1–O1
122.13(9)
82.56(8)
86.69(9)
167.33(9)
118.79(11)
85.60(9)
95.59(10)
125.71(9)
146.19(6)
63.29(6)
63.29(6)
146.19(6)
130.59(9)
91.97(6)
128.04(6)
65.99(6)
79.10(6)
O4–Zn1–O9
N1–Zn1–O1
N1–Zn1–N2
O5–Zn2–O12
O5–Zn2–O8
110.45(9)
85.70(9)
94.43(10)
113.73(10)
81.60(8)
89.31(9)
169.44(9)
128.04(6)
91.97(6)
79.09(6)
65.99(6)
89.04(9)
63.92(6)
80.03(6)
89.19(6)
125.13(6)
N1–Zn1–O9
O9–Zn1–O1
O9–Zn1–N2
O5–Zn2–N4
O12–Zn2–O8
O12–Zn2–N3
127.21(10)
97.27(9)
92.74(10)
126.50(9)
93.65(9)
O5–Zn2–N3
O8–Zn2–N3
94.94(10)
O5#3–Pr1–O1#3
O5–Pr1–O1#3
O4–Pr1–O1#3
O4#3–Pr1–O1#3
O1–Pr1–O1#3
O5#3–Pr1–O8#3
O5–Pr1–O8#3
O4–Pr1–O8#3
O4#3–Pr1–O8#3
O1–Pr1–O8#3
O1#3–Pr1–O8#3
O5#3–Pr1–O8
O5–Pr1–O8
88.83(7)
167.92(6)
80.03(6)
63.92(6)
125.13(6)
89.19(6)
167.93(6)
88.83(7)
95.65(9)
O4–Pr1–O8
O4#3–Pr1–O8
O1–Pr1–O8
O1#3–Pr1–O8
O8#3–Pr1–O8
Complex 4
Bond
Lengths
Bond
Lengths
Bond
Lengths
N1–Zn1
N4–Zn2
O9–Zn2
O12–Zn1
Nd1–O4
Nd1–O4#4
Nd1–O3#4
2.020(3)
2.017(3)
2.023(3)
2.017(3)
2.444(2)
2.444(2)
2.450(2)
N2–Zn1
O3–Zn1
O10–Zn2
2.110(3)
1.968(3)
2.061(3)
N3–Zn2
O4–Zn2
O11–Zn1
2.133(3)
1.985(2)
2.046(3)
Nd1–O3
2.450(2)
2.452(2)
2.452(2)
Nd1–O11#4
Nd1–O11
2.481(3)
2.481(3)
Nd1–O10
Nd1–O10#4
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Table 2 (Contd.)
Complex 4
Bond
Angles
Bond
Angles
Bond
Angles
O3–Zn1–O12
O3–Zn1–O11
O3–Zn1–N2
O11–Zn1–N2
N4–Zn2–O9
113.61(13)
81.28(10)
89.29(12)
169.03(13)
127.58(13)
96.81(13)
93.47(14)
129.52(12)
145.82(8)
63.98(8)
O3–Zn1–N1
O12–Zn1–O11
O12–Zn1–N2
O4–Zn2–N4
O4–Zn2–O10
127.19(13)
93.77(12)
95.15(13)
122.85(13)
82.07(10)
87.26(12)
167.13(12)
78.43(9)
65.72(8)
128.56(8)
91.74(8)
88.34(12)
89.50(8)
126.21(8)
64.06(8)
O12–Zn1–N1
N1–Zn1–O11
N1–Zn1–N2
O4–Zn2–O9
N4–Zn2–O10
N4–Zn2–N3
118.26(15)
86.07(12)
95.29(14)
109.21(11)
85.26(12)
94.59(14)
O9–Zn2–O10
O9–Zn2–N3
O4–Zn2–N3
O10–Zn2–N3
O4–Nd1–O4#4
O4–Nd1–O3#4
O4#4–Nd1–O3#4
O4–Nd1–O3
O4–Nd1–O10#4
O4#4–Nd1–O10#4
O3#4–Nd1–O10#4
O3–Nd1–O10#4
O10–Nd1–O10#4
O4–Nd1–O11#4
O4#4–Nd1–O11#4
O3#4–Nd1–O11#4
O3–Nd1–O11#4
O10–Nd1–O11#4
O10#4–Nd1–O11#4
O4–Nd1–O11
90.19(9)
167.33(8)
126.22(8)
89.50(8)
79.37(8)
64.06(9)
167.33(8)
90.20(9)
93.93(12)
63.98(8)
O4#4–Nd1–O11
O3#4–Nd1–O11
O3–Nd1–O11
O4#4–Nd1–O3
O3#4–Nd1–O3
O4–Nd1–O10
O4#4–Nd1–O10
O3#4–Nd1–O10
O3–Nd1–O10
145.82(8)
125.79(12)
65.72(8)
78.43(9)
91.73(8)
O10–Nd1–O11
O10#4–Nd1–O11
O11#4–Nd1–O11
79.37(8)
128.56(8)
a
Symmetry transformations used to generate equivalent atoms: #13/2 ꢀ x, ꢀ1/2 + y, 3/2 ꢀ z; #2ꢀx + 1, y, ꢀz + 1/2; #3ꢀx, y, ꢀz + 1/2; #4ꢀx + 1, y, ꢀz + 1/2.
using SADABS. The single crystal structures were solved by the absorption spectrum of H4L (1.0 ꢂ 10ꢀ5 M) showed four rela-
direct methods (SHELXS-2016).11a All hydrogen atoms were tively strong absorption peaks at ca. 302, 313, 341 and 355 nm,
included at the calculated positions, and their positions were the former two peaks can be assigned to the p–p* transitions of
rened by a riding model. All non-hydrogen atoms were rened the naphthalene rings. The later two absorption peaks can be
anisotropically using a full-matrix least-squares procedure on F2 assigned to the intra-ligand p–p* transition of the oxime
with SHELXL-2016.11b Crystallographic data and the structure group.15 Compared with the absorption peaks of the free ligand
renements for complexes 1–4 are presented in Table 3.
H4L, the rst absorption peaks were observed at 326, 325, 321
and 325 nm in complexes 1–4, respectively. These peaks are
bathochromically shied, indicating coordination of the (L)4ꢀ
moieties with metal(II/III) ions. Meanwhile, the new peaks
emerged at ca. 382 nm in complexes 1–4, respectively, which
belong to the n–p* charge transfer transitions from the lone-
pair electrons of the N atoms of C]N groups to benzene rings.16
3 Results and discussion
3.1. IR spectra
IR spectra of H4L and its corresponding complexes 1–4 dis-
played various bands in the 4000–400 cmꢀ1 region (Fig. 1).
In the infrared spectrum of H4L, a typical C]N stretching
band appeared at ca. 1603 cmꢀ1, and C]N stretching bands of
complexes 1–4 were observed at 1609–1614 cmꢀ1, indicating
that H4L has coordinated with ZnII ions.12 In addition, the free
ligand H4L exhibited a typical Ar–O stretching frequency at ca.
1239 cmꢀ1, while the Ar–O stretching frequencies in complexes
1–4 were observed at ca. 1232, 1235, 1231 and 1232 cmꢀ1, which
are shied to lower frequencies, indicating that the Zn–O or Ln–
O bond is formed between the oxygen atoms of phenolic group
and the metal ions.13 Meanwhile, the hydroxyl stretching band
of H4L was observed at ca. 3435 cmꢀ1 that belongs to the
phenolic O–H groups. These absorption bands in complexes 1–
4 were observed at ca. 3441–3443 cmꢀ1, indicating the existence
of coordinated water, methanol or ethanol molecules.14
3.3. Crystal structure descriptions
X-ray crystallographic analysis revealed the crystal structures of
complexes 1–4. Selected bond lengths and angles are given in
Table 1
3.3.1. Crystal structure of complex 1. The crystallographic
data revealed that complex 1 ([Zn4(L)2La(NO3)2(OEt)(H2O)]) was
a hetero-pentanuclear complex, crystallizes in the monoclinic
system, space group C2/c, and consists of four ZnII ions, one
LaIII ion, two (L)4ꢀ units, one coordinated ethoxy group, one
coordinated water molecule and two nitrate groups (Fig. 3).
N2O2 sites of the salamo moieties were occupied by four ZnII
ions (Zn1, Zn2, Zn3 and Zn4), the ZnII ions were located in N2O3
coordination spheres, and assumed trigonal bipyramid coor-
dination environment (s1 ¼ 0.68, s2 ¼ 0.71, s3 ¼ 0.69 and s4 ¼
0.64).17 Meanwhile, the eight phenoxo donors (O1, O4, O5, O7,
3.2. UV-Vis spectra
The UV-Vis absorption spectra of H4L and its complexes 1–4 in O12, O13, O19 and O20) from two completely deprotonated
CHCl3/CH3CH2OH solution (v/v ¼ 1 : 1) are shown in Fig. 2. The (L)4ꢀ units as a central O8 site coordinated to LaIII ion, the LaIII
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Fig. 4 (a) View of the intramolecular hydrogen bonding interactions of complex 1. (b) View of an infinite 2D supramolecular structure of
complex 1.
ion lay in an O8 coordination sphere, and adopted a distorted H8A/O10) as shown in Fig. 4.19 Meanwhile, a self-assembled
square antiprismatic coordination environment. Finally, innite 2D supramolecular structure was formed by C12–
complex 1 formed a rare heteropentanuclear 3d–4f complex.18 H12A/O3 and C47–H47A/O15 hydrogen bond interactions20
The distances of Zn/La1, Zn–N, Zn–O and La1–O bonds are in (Fig. 4).
the ranges of 3.6130(5)–3.6513(5), 2.011(3)–2.149(3), 1.957(2)–
3.3.2. Crystal structure of complex 2. The crystallographic
data revealed that complex 2 ([Zn4(L)2Ce(NO3)2(OMe)(MeOH)])
˚
2.085(3) and 2.491(2)–2.537(3) A, respectively.
The intramolecular and intermolecular hydrogen bonds for crystallizes in the monoclinic system, space group C2/c. Unlike
complex 3 are presented in Table 2. Each molecule formed ve complex 1, it consists of four ZnII ions, one CeIII ion, two ligand
intramolecular hydrogen bonds (C23–H23A/O12 and C8– (L)4ꢀ units, one coordinated methoxo group, one coordinated
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number of CeIII ion is 8, consisting of eight phenolic oxygen
atoms from two full deprotonated (L)4ꢀ units and adopted
a distorted square antiprismatic coordination environment
(Fig. 5).18
In the crystal structure of complex 2, there were many
intramolecular hydrogen bonds (C2–H2/O9, C11–H11/O1
and C22–H22A/O7).19 As shown in Fig. 6. Moreover, the 2D
supramolecular structure was formed by C12–H12A/O7
hydrogen bonding interactions in complex 2 (ref. 21) (Fig. 6).
3.3.3. Crystal structure of complex 3. Complex 3 ([Zn4(L)2-
Pr(NO3)2(OEt)(EtOH)]) crystallizes in the monoclinic crystal
system, space group C2/c. X-ray crystallography clearly showed
the formation of complex 3. Different from complexes 1 and 2, it
consists of four ZnII ions, one PrIII ion, two ligand (L)4ꢀ units,
one coordinated ethoxy group, one coordinated ethanol mole-
cule and two monodentate nitrate groups (Fig. S2†).
The ZnII ions also were located in the N2O2 sites, and four
ZnII ions are also penta-coordinated. The ZnII ions (Zn1 and
Zn2) adopted trigonal bipyramid coordination environment
(s1 ¼ 0.67 and s2 ¼ 0.72).17 The PrIII ion was also located in the
O8 site that consists of eight phenoxo oxygen atoms,
forming
a distorted square antiprismatic coordination
environment.18
The main interactions in complex 3 are listed in Table 3, four
pairs of intramolecular hydrogen bonds (C13–H13B/O10,
C24–H24/O7, C27–H27/O9 and C35–H35B/O11) were
formed.19 Besides, The O10 atom of nitrate group as acceptor
formed a hydrogen bond with the donor (C23H23B–) in
complex 3, which adopted a 2D supramolecular structure22
(Fig. S3†).
3.3.4. Crystal structure of complex 4. As shown in Fig. S4,†
X-ray crystallographic analysis of complex
4 ([Zn4(L)2-
Nd(NO3)2(OMe)(MeOH)]) revealed that crystallizes in the
monoclinic system, space group C2/c. Similar to the structure of
complex 2, it consists of four ZnII ions, one NdIII ion, two ligand
(L)4ꢀ units, one coordinated methoxo group, one coordinated
methanol molecule and two monodentate nitrate groups.
All ZnII ions lay in N2O3 coordination spheres. The Zn1 and
Zn2 (Zn1#4 and Zn2#4) ions were all made of the N2O2 cavities
and one coordinated nitrate group, which assumed trigonal
bipyramid coordination environments (s1 ¼ 0.69 and s2
¼
0.66).17 The NdIII ion exhibited an O8 coordination sphere,
which is made of eight phenoxo donors (O3, O4, O10, O11,
O3#4, O4#4, O10#4 and O11#4) from two completely deproto-
nated (L)4ꢀ units, while the central NdIII ion is octa-
coordinated with a distorted square antiprismatic coordina-
tion environment.18
Fig.
5 (a) Molecule structure of complex 2 ([Zn4(L)2Ce(NO3)2(-
OMe)(MeOH)]) (hydrogen atoms and solvent molecules are omitted
for clarity). (b) Coordination polyhedrons for ZnII and CeIII ions of
complex 2.
In complex 4, three pairs of signicant intramolecular
hydrogen bonds (C2–H2A/O9, C11–H11/O1 and C22–H22A/
O7) were formed19 (Fig. S5(a)†). Meanwhile, complex 4 molecules
formed
a 2D supramolecular structure by intermolecular
hydrogen bonds (C6–H6/O8 and C12–H12A/O7)23 (Fig. S5(b)†).
methanol molecule and two monodentate nitrate groups
(Fig. 5).
Zn1 and Zn2 ions were located in penta-coordinated
spheres and adopted trigonal bipyramid coordination envi-
ronments (s1 ¼ 0.704 and s2 ¼ 0.67).17 The coordination
3.4. Spectroscopic properties
The free ligand H4L and its corresponding complexes 1–4 were
excited at 385 nm (lex) respectively (Fig. 7). The emission
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Fig. 6 (a) View of the intramolecular hydrogen bonding interactions of complex 2. (b) View of an infinite 2D supramolecular structure of
complex 2.
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Fig. 7 (a) Visible luminescence spectra of complexes 1–3. (b) NIR luminescence spectrum of complex 4.
spectrum of H4L exhibited a broad emission band, and the and 4F3/2 / 4I13/2 transitions.25 The ligand (L)4ꢀ units could serve
emission maximum at 454 nm, which can be assigned to the p– as sensitizing agent for NdIII luminescence in the NIR region.
p* electronic transitions in the ligand.24 Compared to H4L, the
absorption peaks of complexes 1–3 are bathochromically-
shied, which is may originated from the LMCT emission.
4 Conclusions
Due to energy mismatch, complexes 1–3 have no NIR lumi-
In this work, four rare hetero-pentanuclear 3d–4f complexes of
a bis(salamo)-type ligand (H4L) have been synthesized and
structurally characterized. In complexes 1–4, all four ZnII ions
presented N2O3 coordination spheres. The LnIII ion exhibited an
O8 coordination sphere, and assumed a distorted square
nescence. The NIR luminescence spectrum of complex 4 excited at
385 nm showed the characteristic emitting peaks at ca. 871, 917,
1055 and 1324 nm (Fig. 7(b)). These emission peaks are typical
peaks of NdIII ions, and correspond to 4F3/2 / 4I9/2, 4F3/2 / 4I11/2
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Table 3 Hydrogen bonding distances (A˚) and bond angles (o) for complexes 1–4
D–H/A
d(D–H)
d(H–A)
d(D–A)
:D–X–A
Sum
Complex 1
C7–H7A/O14
C47–H47B/O21
C56–H56A/O15
C12–H12A/O3
C47–H47A/O15
0.93
0.97
0.97
0.97
0.97
2.55
1.89
2.54
2.44
2.56
3.436(5)
2.653(12)
3.507(8)
3.214(5)
3.244(8)
159
134
174
137
128
1 ꢀ x, 1 ꢀ y, 1 ꢀ z
ꢀ1/2 + x, 1/2 + y, z
Complex 2
C2–H2/O9
C22–H22A/O7
0.95
0.99
2.51
2.51
3.451(5)
3.490(6)
173
172
1 ꢀ x, y, 1/2 ꢀ z
Complex 3
C13–H13B/O10
C23–H23B/O10
C27–H27/O9
C35–H35B/O11
0.99
0.99
0.95
0.98
2.53
2.54
2.50
2.58
3.516(4)
3.148(4)
3.448(4)
3.438(8)
173
120
175
146
1/2 + x, 1/2 + y, z
ꢀx, y, 1/2 ꢀ z
ꢀx, y, 1/2 ꢀ z
Complex 4
C2–H2A/O9
C6–H6/O8
C22–H22A/O7
0.95
0.95
0.99
2.51
2.56
2.52
3.456(6)
3.361(11)
3.499(6)
172
142
172
1 ꢀ x, y, 1/2 ꢀ z
ꢀ1/2 + x, 1/2 ꢀ y, ꢀ1/2 + z
antiprismatic coordination environment. In a conclusion, the
studies demonstrated that incorporation of salamo-like ligand
was an optimistic approach to build ZnII–LnIII complexes which
can display excellent spectroscopic resting with the lanthanide
ions used.
M. Evangelisti and C. J. Milioset, Dalton Trans., 2016, 45,
18591–18602.
2 (a) L. Q. Chai, J. J. Huang, J. Y. Zhang and Y. X. Li, J. Coord.
Chem., 2015, 68, 1224–1237; (b) L. Q. Chai, K. Y. Zhang,
L. J. Tang, J. Y. Zhang and H. S. Zhang, Polyhedron, 2017,
130, 100–107; (c) L. Q. Chai, L. J. Tang, L. C. Chen and
J. J. Huang, Polyhedron, 2017, 122, 228–240; (d) L. Q. Chai,
G. Liu, J. Y. Zhang, J. J. Huang and J. F. Tong, J. Coord.
Chem., 2013, 66, 3926–3938; (e) L. Q. Chai, J. J. Huang and
H. S. Zhang, Spectrochim. Acta, Part A, 2014, 131, 526–533.
3 (a) Q. Zhao, Z. L. Wei, Q. P. Kang, H. Zhang and W. K. Dong,
Spectrochim. Acta, Part A, 2018, 203, 472–480; (b) L. Chen,
W. K. Dong, H. Zhang, Y. Zhang and Y. X. Sun, Cryst.
Growth Des., 2017, 17, 3636–3648; (c) Y. D. Peng, F. Wang,
L. Gao and W. K. Dong, J. Chin. Chem. Soc., 2018, 65, 893–
899; (d) X. Y. Dong, Q. P. Kang, X. Y. Li, J. C. Ma and
W. K. Dong, Crystals, 2018, 8, 139; (e) L. Z. Liu, M. Yu,
X. Y. Li, Q. P. Kang and W. K. Dong, Chin. J. Inorg. Chem.,
2019, 35, 1283–1294.
Conflicts of interest
There are no conicts to declare.
Acknowledgements
This work was supported by the National Natural Science
Foundation of China (21761018), Science and Technology
Program of Gansu Province (18YF1GA054) and the Program for
Excellent Team of Scientic Research in Lanzhou Jiaotong
University (201706), three of which are gratefully acknowledged.
4 (a) X. Y. Li, L. Chen, L. Gao, Y. Zhang, S. F. Akogun and
W. K. Dong, RSC Adv., 2017, 7, 35905–35916; (b) L. H. Li,
W. K. Dong, Y. Zhang, S. F. Akogun and L. Xu, Appl.
Organomet. Chem., 2017, e3818.
5 (a) X. Q. Song, P. P. Liu, Z. R. Xiao, X. Li and Y. A. Liu, Inorg.
Chim. Acta, 2015, 438, 232–244; (b) Y. A. Liu, C. Y. Wang,
M. Zhang and X. Q. Song, Polyhedron, 2017, 127, 278–286;
(c) P. P. Liu, L. Sheng, X. Q. Song, W. Y. Xu and Y. A. Liu,
Inorg. Chim. Acta, 2015, 434, 252–257.
6 (a) H. L. Wu, G. L. Pan, Y. C. Bai, H. Wang, J. Kong, F. R. Shi,
Y. H. Zhang and X. L. Wang, J. Chem. Res., 2014, 38, 211–217;
(b) H. L. Wu, Y. C. Bai, Y. H. Zhang, G. L. Pan, J. Kong,
F. R. Shi and X. L. Wang, Z. Anorg. Allg. Chem., 2014, 640,
2062–2071; (c) H. L. Wu, G. L. Pan, Y. C. Bai, Y. H. Zhang,
H. Wang, F. R. Shi, X. L. Wang and J. Kong, J. Photochem.
References
1 (a) Y. X. Sun, L. Xu, T. H. Zhao, S. H. Liu, G. H. Liu and
X. T. Dong, Synth. React. Inorg., Met.-Org., Nano-Met. Chem.,
2013, 43, 509–513; (b) Y. X. Sun, S. T. Zhang, Z. L. Ren,
X. Y. Dong and L. Wang, Synth. React. Inorg., Met.-Org.,
Nano-Met. Chem., 2013, 43, 995–1000; (c) Y. X. Sun and
X. H. Gao, Synth. React. Inorg., Met.-Org., Nano-Met. Chem.,
2011, 41, 973–978; (d) Y. X. Sun, L. Wang, X. Y. Dong,
Z. L. Ren and W. S. Meng, Synth. React. Inorg., Met.-Org.,
Nano-Met. Chem., 2013, 43, 599–603; (e) Y. X. Sun, R. E. Lu,
X. R. Li, Y. Y. Zhao and C. Y. Li, Chin. J. Inorg. Chem., 2015,
31, 1055–1062; (f) G. Murugavel, P. Sadhu and
T. Punniyamurthy, Chem. Rec., 2016, 16, 1906–1917; (g)
A. B. Canaj, M. Siczek, M. Otr˛eba, T. Lis, G. Lorusso,
37342 | RSC Adv., 2019, 9, 37331–37343
This journal is © The Royal Society of Chemistry 2019

View Article Online
Paper
RSC Advances
Photobiol., B, 2014, 135, 33–43; (d) H. L. Wu, C. P. Wang, 14 (a) L. Gao, F. Wang, Q. Zhao, Y. Zhang and W. K. Dong,
F. Wang, H. P. Peng, H. Zhang and Y. C. Bai, J. Chin. Chem.
Soc., 2015, 62, 1028–1034; (e) H. L. Wu, Y. C. Bai,
Y. H. Zhang, Z. Li, M. C. Wu, C. Y. Chen and J. W. Zhang,
Polyhedron, 2018, 139, 7–16; (b) L. W. Zhang, X. Y. Li,
Q. P. Kang, L. Z. Liu, J. C. Ma and W. K. Dong, Crystals,
2018, 8, 173.
J. Coord. Chem., 2014, 67, 3054–3066; (f) H. L. Wu, 15 (a) Q. P. Kang, X. Y. Li, Q. Zhao, J. C. Ma and W. K. Dong,
G. L. Pan, Y. C. Bai, H. Wang, J. Kong, F. R. Shi,
Y. H. Zhang and X. L. Wang, Res. Chem. Intermed., 2015,
41, 3375–3383; (g) C. Y. Chen, J. W. Zhang, Y. H. Zhang,
Z. H. Yang, H. L. Wu, G. L. Pana and Y. C. Bai, J. Coord.
Appl. Organomet. Chem., 2018, 32, e4379; (b) X. Y. Li,
Q. P. Kang, L. Z. Liu, J. C. Ma and W. K. Dong, Crystals,
2018, 8, 43; (c) Y. D. Peng, X. Y. Li, Q. P. Kang, G. X. An,
Y. Zhang and W. K. Dong, Crystals, 2018, 8, 107.
Chem., 2015, 68, 1054–1071; (h) H. L. Wu, Y. Bai, 16 (a) L. Gao, C. Liu, F. Wang and W. K. Dong, Crystals, 2018, 8,
J. K. Yuan, H. Wang, G. L. Pan, X. Y. Fan and J. Kong, J.
Coord. Chem., 2012, 65, 2839–2851.
7 (a) L. W. Zhang, L. Z. Liu, F. Wang and W. K. Dong,
Molecules, 2018, 23, 1141; (b) F. Wang, L. Gao, Q. Zhao,
Y. Zhang, W. K. Dong and Y. J. Ding, Spectrochim. Acta,
77; (b) P. Wang and L. Zhao, Synth. React. Inorg., Met.-Org.,
Nano-Met. Chem., 2016, 46, 1095–1101; (c) L. Zhao,
L. Wang, Y. X. Sun, W. K. Dong, X. L. Tang and X. H. Gao,
Synth. React. Inorg., Met.-Org., Nano-Met. Chem., 2012, 42,
1303–1308.
Part A, 2018, 190, 111–115; (c) J. Hao, X. Y. Li, Y. Zhang 17 P. Seth, S. Ghosh, A. Figuerola and A. Ghosh, Dalton Trans.,
and W. K. Dong, Materials, 2018, 11, 523; (d) F. Wang, 2013, 43, 990–998.
L. Z. Liu, L. Gao and W. K. Dong, Spectrochim. Acta, Part A, 18 (a) X. Y. Dong, Q. Zhao, L. W. Zhang, H. R. Mu, H. Zhang and
2018, 203, 56–64; (e) L. Z. Liu, L. Wang, M. Yu, Q. Zhao,
Y. Zhang, Y. X. Sun and W. K. Dong, Spectrochim. Acta, Part
A, 2019, 222, 117209.
8 (a) S. S. Zheng, W. K. Dong, Y. Zhang, L. Chen and Y. J. Ding,
New J. Chem., 2017, 41, 4966–4973; (b) Q. P. Li, Y. Peng,
J. J. Qian, T. Yan, L. Du and Q. H. Zhao, Dalton Trans.,
2019, 48, 12880–12887; (c) J. J. Qian, T. T. Li, Y. Hua and
W. K. Dong, Molecules, 2018, 23, 1006; (b) Q. Zhao, X. X. An,
L. Z. Liu and W. K. Dong, Inorg. Chim. Acta, 2019, 490, 6–15.
19 (a) X. X. An, Q. Zhao, H. R. Mu and W. K. Dong, Crystals,
2019, 9, 101; (b) L. Wang, X. Y. Li, Q. Zhao, L. H. Li and
W. K. Dong, RSC Adv., 2017, 7, 48730–48737; (c)
H. J. Zhang, J. Chang, H. R. Jia and Y. X. Sun, Chin. J.
Inorg. Chem., 2018, 34, 2261–2270.
S. M. Huang, Chem. Commun., 2017, 53, 13027–13030; (d) 20 (a) Y. J. Dong, X. Y. Dong, W. K. Dong, Y. Zhang and
J. J. Qian, Q. P. Li, L. F. Liang, Y. Yang, Z. Cao, P. P. Yu,
S. M. Huang and M. C. Hong, Chem. Commun., 2016, 52,
9032–9035.
L. S. Zhang, Polyhedron, 2017, 123, 305–315; (b)
L. W. Zhang, L. Z. Liu, F. Wang and W. K. Dong, Molecules,
2018, 23, 1141.
9 X. Y. Dong, Q. Zhao, Q. P. Kang, X. Y. Li and W. K. Dong, 21 B. Yu, C. Y. Li, Y. X. Sun, H. R. Jia, J. Q. Guo and J. Li,
Crystals, 2018, 8, 230. Spectrochim. Acta, Part A, 2017, 184, 249–254.
10 (a) S. Akine, T. Taniguchi, W. K. Dong, S. Masubuchi and 22 (a) G. Li, J. Hao, L. Z. Liu, W. M. Zhou and W. K. Dong,
T. Nabeshima, J. Org. Chem., 2005, 70, 1704–1711; (b)
J. Hao, X. Y. Li, L. Wang, Y. Zhang and W. K. Dong,
Spectrochim. Acta, Part A, 2018, 204, 388–402.
Crystals, 2017, 7, 217; (b) Y. Zhang, L. Z. Liu, Y. D. Peng,
N. Li and W. K. Dong, Transition Met. Chem., 2019, 44,
627–639.
11 (a) G. M. Sheldrick, SHELXS-2016, Program for crystal 23 (a) Q. P. Kang, X. Y. Li, L. Wang, Y. Zhang and W. K. Dong,
¨
¨
structure solution, University of Gottingen, Gottingen
Germany, 2016; (b) G. M. Sheldrick, SHELXL-2016, Program
Appl. Organomet. Chem., 2019, 32, e5013; (b) Y. X. Sun,
Y. Y. Zhao, C. Y. Li, B. Yu, J. Q. Guo and J. Li, Chin. J.
Inorg. Chem., 2016, 32, 913–920.
¨
for crystal structure renement, University of Gottingen,
¨
Gottingen Germany, 2016.
24 (a) X. Y. Li, Q. P. Kang, C. Liu, Y. Zhang and W. K. Dong, New
J. Chem., 2019, 43, 4605–4619; (b) H. R. Jia, J. Chang,
H. J. Zhang, J. Li and Y. X. Sun, Crystals, 2018, 8, 272; (c)
J. Li, H. J. Zhang, J. Chang, H. R. Jia, Y. X. Sun and
Y. Q. Huang, Crystals, 2018, 8, 176; (d) Q. P. Kang, X. Y. Li,
Z. L. Wei, Y. Zhang and W. K. Dong, Polyhedron, 2019, 165,
38–50.
12 (a) X. Y. Dong, Y. X. Sun, L. Wang and L. Li, J. Chem. Res.,
2012, 36, 387–390; (b) Z. L. Ren, J. Hao, P. Hao, X. Y. Dong,
Y. Bai and W. K. Dong, Z. Naturforsch., 2018, 73b, 203–210;
(c) L. Xu, L. C. Zhu, J. C. Ma, Y. Zhang, J. Zhang and
W. K. Dong, Z. Anorg. Allg. Chem., 2015, 641, 2520–2524.
13 (a) L. Wang, J. Hao, L. X. Zhai, Y. Zhang and W. K. Dong,
Crystals, 2017, 7, 277; (b) J. Chang, H. J. Zhang, H. R. Jia 25 W. K. Dong, J. C. Ma, L. C. Zhu and Y. Zhang, Cryst. Growth
and Y. X. Sun, Chin. J. Inorg. Chem., 2018, 34, 2097–2107.
Des., 2016, 16, 6903–6914.
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RSC Adv., 2019, 9, 37331–37343 | 37343