Functional Sensing Materials Based on Lanthanide N-heterocyclic

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Functional Sensing Materials Based on Lanthanide N-heterocyclic Polycarboxylate Crystal Frameworks for Detecting Thiamines Yang Wang, Ning Du, Xu Zhang, Yu Wang, Yong Heng Xing, Fengying Bai, Li-Xian Sun, and Zhan Shi Cryst. Growth Des., Just Accepted Manuscript • DOI: 10.1021/acs.cgd.7b01684 • Publication Date (Web): 06 Mar 2018 Downloaded from http://pubs.acs.org on March 7, 2018

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Crystal Growth & Design

Functional Sensing Materials Based on Lanthanide N-heterocyclic Polycarboxylate Crystal Frameworks for Detecting Thiamines Yang Wang a, Ning Du a, Xu Zhang a, Yu Wang a, Yong-Heng Xing a,*, Feng-Ying Bai a,*,

Li-Xian Sun b, Zhan Shi c

a

College of Chemistry and Chemical Engineering, Liaoning Normal University,

Huanghe Road 850#, Dalian 116029, P. R. China. b

Guangxi Key Laboratory of Information Materials, Guilin University of Electronic

Technology, Guilin 541004, P. R. China. c

State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of

Chemistry, Jilin University, Changchun City, 130012, P. R. China.

KEYWORDS: Lanthanide coordination polymers; Thiamines; Crystal structure; Luminescent sensing

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ABSTRACT: A family of polymers [Ln2(ad)(Had)2(NO3)2(H2L)2(H2O)2]·2H2O (Ln= Nd (1), Sm (2), Eu (3)) and [Ln(ad)(H2L)(H2O)2]·NO3·2H2O (Ln= Gd (4), Tb (5), Dy (6)) was synthesized.

The polymers were characterized by powder

X-ray diffraction (PXRD), infrared spectra (IR), single-crystal X-ray diffraction, thermogravimetric analysis (TG) and elemental analysis (C, H, N).

Based on

the luminescence properties of the polymers, we used the polymer 5 as an example to detect thiamines (TPP, TMP, TCl).

In the way that was expected, the

polymer 5 could quickly detect TPP, TMP and TCl, which could be used as a typical luminescence sensing materials in the field of the optical detection.

INTRODUCTION

Nowadays, the sensible design and synthesizing of metal–organic coordination polymers by central metal clusters (or metal ions) and organic polycarboxylate ligands have been investigated extensively.1-6

Particularly,

lanthanide coordination polymers have attracted intense interest, not only due to their unique outstanding architectures but also as the potential functional properties, such as luminescence sensor, magnetism, catalysis activity, gas storage, ion exchange, diagnostic tool, biologic activity and sensor over light-emitting device (LED, OLED), etc.7-8

In the meantime, lanthanide

coordination polymers containing N-heterocyclic ligands show excellent luminescent by the antenna effect, as a general, in which the N-heterocyclic ligand function is as sensitizers.9-11

In this aspect of the work, the ligand H2L


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{2,6-bis(5-methyl-1H-pyrazol-3-yl)pyridine}12 was extensively investigated. Furthermore, the “-NH” in the H2L ligand (including pyrazole and pyridine) can act as the Lewis base donors and Lewis acid acceptors at the same molecule.9, 12

Up to now, the crystal structures of some related compounds

with 2,6-bis(5-methyl-1H-pyrazol-3-yl)pyridine (H2L) have been reported, such as

[Cd(H2L)2]·(NO3)2·2H2O,

[Cd(H2L)2]·(OH)2·(EtOH)0.5,

[Zn(H2L)(2,6-pdc)]·(2,6-H2pdc)1.5·MeOH·0.5H2O, [Zn(H2L)2][Zn(2,5-Hpdc)3]2·1.5H2O,

[Zn2(HL)2(µ2-SO4)]·2H2O

[Zn(H2L)(H2O)2](SO4)·0.87H2O, etc.9, 12

Although these molecules (tridentate

and

N-heterocyclic ligand) can also serve as efficient antenna to sensitize the emission of lanthanide ions, explorations application studies about such kinds of coordination polymers are still quite limited. To our knowledge, many common analytical methods have been applied in detecting the analyte such as electrochemistry, ion chromatography, spectrophotometry, synchrotron radiation X-ray spectrometry, etc.

While,

complicated sample preparations, high costs and sophisticated instruments often restricted these analytical application.13

Therefore, it is important to find

a simple and practical method with high sensitivity, strong selectivity and less reagent in the detection of concentration and composition analysis.14

While

the choice of sensor material is the most key part to get the effective detection.15-22

Luminescent metal−organic coordination polymers are well

explored as chemical sensor materials, as their narrow spectral width, stable



chemical structure and long fluorescence lifetime.13

Page 4 of 45

Such as, detection of

explosive nitroaromatics; 6, 8, 11, 23-28 detection of metal cations;7, 30-35 detection of anions;7, 36-38 sensing of organic small molecules ;17, 31, 39-42 sensing of solvent molecules and so on.40, 43 In addition, thiamines are also called vitamin B1,44-45 including three kinds of

the

thiamine:

thiamine

bydrochloride

monophosphate chloride (TMP);12, (TPP).12, 52-57 (Scheme 1)

47, 50, 51

(TCl);12,

44,

46-49

thiamine

thiamine pyrophosphate chloride

As an important small biomolecule, when organism

lacks thiamines, the following response can appear in turn, such as: dry beriberi, wet beriberi, wernicke encephalopathy, and Korsakoff syndrome, and so on.

In view of the closely related with the health of human beings, the

effective detection for the biomolecule thiamines is a significant work. Up to now, it is well established that the application of the lanthanide coordination polymers as functional luminescent probes for effective detection of biomolecules (thiamine) in water solutions has been rarely reported.12, 58-60 Thus, it is urgent for the development of selective and sensitive thiamine chemsensors. So, we present the synthesis and structure of lanthanide coordination polymers 1-6, and the sensing behavior of the polymer 5 in this work.

The

polymer 5 exhibits highly selective and sensitive sensing for the thiamines when detects very low concentrations.

The experimental results clearly

indicated that there was the strong intermolecular force between the polymer 5


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and thiamines in very low concentrations.

The result shows the luminescence

material is promising in the field of detecting thiamines.

Scheme 1. Thiamines’ molecular structures: (a) TCl; (b) TMP; (c) TPP.

EXPERIMENTAL

Materials and Methods

In this work, the characterizations and properties of the polymers were made, including elemental analysis (EA), infrared spectra (200-4000 cm-1), thermogravimetric analyses (30 to 1000 ºC), powder X-ray diffraction (5° < 2θ < 60°), luminescence spectra (200-800 nm), UV-vis absorption spectra (200-800 nm).

The more details about the instrumentation have been

presented in the Supporting Information (ESI).

Preparation of the coordination polymers.

Ln(NO3)3·6H2O (0.13 g, 0.3 mmol, Ln= Nd (1), Sm (2), Eu (3), Gd (4), Tb (5), Dy (6)), H2L (0.010 g, 0.04 mmol), adipic acid (0.015 g, 0.1 mmol), H2O (10 ml) and



EtOH (2 ml) were mixed in a 25 mL beaker.

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In the reaction system, the pH value

was 3-4 for polymer 1, 2 and 3，， and 5-6 for polymer 4, 5 and 6.

After stirrig for 2 h,

the mixture was placed to a 25 mL Teflon-lined stainless vessel and heated at 120 ºC for 3 days.

The product was filtered and washed with distilled water and air dried.

Colorless block single crystals for 1-6 were obtained. [Nd2(ad)(Had)2(NO3)2(H2L)2(H2O)2]·2H2O (1): Yield: 0.26 g, 61% (based on Nd(NO3)3·6H2O). 12.03%.

Anal. Calc. for C44H60N12O22Nd2 (1397.52): C, 37.82; H, 4.33; N,

Found: C, 37.13; H, 4.02; N, 11.88%.

IR data (KBr, cm-1): 3475, 3274,

3082, 3072, 2931, 2858, 1684, 1642, 1559, 1439, 1423. [Sm2(ad)(Had)2(NO3)2(H2L)2(H2O)2]·2H2O (2): Yield: 0.22 g, 52% (based on Sm(NO3)3·6H2O). 11.92%.

Anal. Calc. for C44H60N12O22Sm2 (1409.76): C, 37.49; H, 4.29; N,

Found: C, 37.35; H, 4.17; N, 11.48%.

IR data (KBr, cm-1): 3428, 3262,

3144, 3075, 2938, 2870, 1692, 1643, 1552, 1442, 1436. [Eu2(ad)(Had)2(NO3)2(H2L)2(H2O)2]·2H2O (3): Yield: 0.24 g, 56% (based on Eu(NO3)3·6H2O). 11.90%.

Anal. Calc. for C44H60N12O22Eu2 (1412.96): C, 37.40; H, 4.28; N,

Found: C, 37.12; H, 4.12; N, 11.58%.

IR data (KBr, cm-1): 3388, 3264,

3138, 3080, 2944, 2865, 1685, 1650, 1550, 1443, 1404. [Gd(ad)(H2L)(H2O)2]·NO3·2H2O

(4):

Yield:

0.13

g,

62%

(based

on

Gd(NO3)3·6H2O). Anal. Calc. for C19H29N6O11Gd (674.73): C, 33.82; H, 4.34; N, 12.46%.

Found: C, 33.85; H, 4.37; N, 12.48%.

IR data (KBr, cm-1): 3455, 3435,

3071, 3041, 2939, 2851, 1658, 1582, 1543, 1534. [Tb(ad)(H2L)(H2O)2]·NO3·2H2O

(5):

Yield:

0.14


g,

67%

(based

on

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Tb(NO3)3·6H2O). Anal. Calc. for C19H29N6O11Tb (676.40): C, 33.74; H, 4.33; N, 12.43%.

Found: C, 33.77; H, 4.38; N, 12.49%.

IR data (KBr, cm-1): 3449, 3420,

3073, 3041, 2927, 2859, 1631, 1576, 1547, 1449. [Dy(ad)(H2L)(H2O)2]·NO3·2H2O

(6):

Yield:

0.13

g,

65%

(based

on

Dy(NO3)3·6H2O). Anal. Calc. for C19H29N6O11Dy (677.97): C, 33.66; H, 4.32; N, 12.40%.

Found: C, 33.69; H, 4.35; N, 12.46%.

IR data (KBr, cm-1): 3443, 3427,

3069, 3030, 2929, 2861, 1641, 1582, 1533, 1455. The infrared spectra (IR) and the descriptions of the polymers 1-6 were shown in the Supporting Information (ESI).

X-ray crystallographic determination.

The polymers 1-6 were measured by X-ray crystallographic diffraction. We used independent reflection data (I > 2σ(I)) in crystals structure analysis, and the crystal structures were refined by SHELXL-97 with the direct method. 61,62

The SADABS program was used to perform the semi-empirical

absorption corrections.63 Table 1.

The crystallographic data and details were given in

The selected bond lengths were given in Table 2.

For the more

details about the important bond lengths and angles, hydrogen bond lengths (Å) and angles (°) and the corresponding descriptions have been presented in the Supporting Information (ESI).

For the crystallography data of the polymer 2

was not perfect, there are “Alert level A” about “sine (theta_max)/wavelength” and “Resolution” in the “checkCIF/PLATON report”.



Page 8 of 45

RESULTS AND DISCUSSION

Synthesis

A family of Ln–H2L–ad coordination polymers were obtained for the first time.

In the process of experiment, we found that there are obviously different

physical and chemical properties between the rigid and flexible ligands, to make them very difficult to coordinate lanthanide ions simultaneously.

We

tried to prepare the Ln–H2L–ad system polymers with the reaction conditions: the molar ratio of Ln(NO3)3·H2O : H2L : ad in the value of 29 : 4 : 10, pH valueat at 5-6 and under 120 oC. polymers 1-3 were obtained. reaction conditions slightly.

After 3 days, only single crystals of the Subsequently, we attempted to exchange

After trying many experiments, when we only

adjusted the pH value to 3-4, other reaction conditions unchanged, single crystals Ln–H2L–ad (Ln= Gd, Tb, Dy) with well crystal and desired yield were obtained.

Through these experiments, the results show that the pH value of

the reaction system may be a main factor for obtaining the desired complexes. A comparison of the reaction processes was given in Scheme 2 to futher explore the optimal experimental conditions.

It should be pointed out that the

the inherent feature of the rare earth element plays the critical role in the reaction system.

They were divided into two categories, light rare earth

element (1, 2 and 3) and heavy rare earth element (4, 5 and 6).


In this work,

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we take two kinds of the polymers (2 and 6) as the example to discuss their structural characterization.

Scheme 2. The comparison of the reaction conditions of the polymers. Crystal structure description

[Sm2(ad)(Had)2(NO3)2(H2L)2(H2O)2]·2H2O (2).

Single-crystal X-ray

diffraction analysis revealed that the polymer 2 was a 3D framework with Triclinic space group(P 1 ).

The molecular structure of the polymer 2 consisted

of two Sm atoms, two H2L ligands, three adipic acid ligands (one bridging coordination adipic acid and two terminal coordination adipic acid), two NO3anions and four H2O molecules (two lattice H2O and two coordination H2O). As shown in Figure 1a, the Sm atom is ten-coordinated, coming into being a mildly twisty bicapped square antiprism polyhedron configuration (Figure 2). As can been seen from the figure, three N atoms (N2, N3 and N4) were from H2L ligand with bond length of 2.548(4)–2.672(4) Å, four O atoms (O3, O4,



Page 10 of 45

O5 and O6) were from the carboxyl group of two adipic acid ligands with the bond distances in the range of 2.484(3)–2.522(3) Å, two O atoms (O7 and O8) came from coordination NO3- anion with the bond length of 2.535(3) and 2.797(4) Å, and O10 atom came from coordination water molecule with the bond distance of 2.442(3) Å.

For the polymer 2, H2L ligands adopted

tridentate chelate coordination with a µ1–η1-η1-η1 fashion.

The flexible adipic

acid ligand had two coordination modes: µ2-η1-η1-η1-η1 and µ1-η1-η1 fashion). The building unit Sm(H2L)(Had) was linked by the bridging adipic acid ligand to form a dimer (Figure 1a). Three types of hydrogen bonds were in the polymer 2: (i) O-H···O: O1–H1···O6 and O1W–H1WB···O9 (O1W from lattice water, O1 and O6 from adipic acid ligands, O9 from coordination NO3- anion); (ii) N-H···O: N1–H1D···O8 and N5–H5···O2 (N1 and N5 from uncoordinated nitrogen from the H2L ligand, O2 from adipic acid ligands, and O8 from coordination NO3anion); (iii) C-H···O: including C6–H6···O5 and C11–H11···O3 (C6 and C11 from H2L ligand, O3 and O5 from adipic acid ligands).

The adjacent building

units Sm2(H2L)2(Had)2(ad) were linked and formed a 1D chain by the hydrogen bonds of O1–H1···O6, N5–H5···O2 and C6–H6···O5 (Figure 1b).

The chains

were linked by hydrogen bonds of N1–H1D···O8 and formed a 2D layer (Figure 1c).

Furthermore, the hydrogen bonds of C11–H11···O3 linked the

layer to form a three-dimensional network structure (Figure 1d).

In addition,

the rest of hydrogen bonds further enhanced the stability of the crystal


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structure.

The crystal structures of the polymer 1 and 3 were similar to that of

the polymer 2.

Fig. 1 (a): The molecular structure of the polymer 2; (b): The 1D chain by the hydrogen bonds O1–H1···O6, N5–H5···O2 and C6–H6···O5; (c): The 2D layer though the hydrogen bonds of N1–H1D···O8; (d): 3D network by the hydrogen bonds of C11–H11···O3.

Fig. 2 The distorted bicapped square antiprism polyhedron structure of the polymer 2.



[Gd(ad)(H2L)(H2O)2]·NO3·2H2O (4).

Page 12 of 45

The polymer 4 was a 2D

framework with the Monoclinic space group P21/c.

The molecular structure of

the polymer 4 contained one Gd atom, one H2L ligand, one adipic acid ligand, four H2O molecules (two lattice H2O and two coordination H2O) molecules and one free NO3- anion. nine-coordinated.

As shown in Figure 3a, the Gd atom was

Three nitrogen atoms (N2, N3 and N4) were from H2L

ligand (bond lengths of Gd–NL 2.504(4)–2.604(4) Å), four oxygen atoms (O1, O2, O3 and O4) were from the carboxyl group of two adipic acid ligands (the bond distances of 2.439(3)–2.485(3) Å), and two oxygen atoms (O5 and O6) were from coordinated water (bond lengths of 2.395(3) and 2.411(3) Å).

The

Gd and coordinated atoms formed a mildly twisty tricapped trigonal prism polyhedron configuration, as shown in Figure 4.

For the polymer 4, the H2L

employed tridentate chelate coordination with µ1–η1-η1-η1 fashion.

The

coordination mode of adipic acid in the polymer acted as a µ2-η1-η1-η1-η1 fashion linker with each carboxyl group in a µ1–η1–η1 fashion.

The adipic

acid ligand linked the adjacent building units to form a 1D chain (Figure 3b). There were three types of hydrogen bonds in the polymer 4: (i) O-H···O: O6–H6A···O1W, O2W–H2WB···O9 and O5–H5A···O7 (O1W and O2W from lattice waters, O5 and O6 from coordination waters, O7 and O9 from free NO3anions); (ii) N-H···O: N5–H5···O7 (N5 from uncoordinated nitrogen of the H2L ligand, O7 from free NO3- anion); (iii) C-H···O: C3–H3···O1, C6–H6···O1 and C11–H11···O3 (C3, C6 and C11 from H2L ligand, O1 and O3 from adipic acid


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ligands).

The

hydrogen

bonds

of

C3–H3···O1,

C6–H6···O1

and

C11–H11···O3 furthermore linked the chain to form a 2D superamolecular layer structure (Figure 3c).

The rest of hydrogen bonds further enhanced the

stability of the crystal structure.

The crystal structures of the polymers 5 and 6

were similar to that of the polymer 4.

Fig. 3 (a) The molecular structure of the polymer 4; (b) The 1D chain by the adipic acid ligand; (c) The 2D layer though the hydrogen bonds of C3–H5···O1, C6–H6···O1 and C11–H11···O3.



Page 14 of 45

Fig. 4 The distorted tricapped trigonal prism coordination environment of Ga in the polymer 4. Table 1 Crystallographic data for the polymers 1-6. Polymers

1

2

3

4

5

6

Formula

C44H60N12O22Nd2

C44H60N12O22Sm2

C44H60N12O22Eu2

C19H29N6O11Gd

C19H29N6O11Tb

C19H29N6O11Dy

-1

M(g·mol )

1397.52

1409.76

1412.96

674.73

676.40

679.98

Crystal system

Triclinic

Triclinic

Triclinic

Monoclinic

Monoclinic

Monoclinic

Space group

P1

P1

P1

P2(1)/c

P2(1)/c

P2(1)/c

a(Å)

10.0132(7)

10.0117(6)

10.0205(14)

10.5304(5)

10.531(3)

10.541(2)

b(Å)

12.5226(9)

12.4560(7)

12.3989(18)

10.3752(5)

10.338(3)

10.3192(18)

c(Å)

12.8666(9)

12.8457(7)

12.8384(18)

24.7489(11)

24.713(8)

24.695(4)

α(º)

94.9140(10)

94.8990(10)

94.922(2)

90

90

90

β(º)

104.5490(10)

104.7430(10)

104.857(2)

100.1750(10)

100.218(6)

100.392(3)

γ(º)

113.4010(10)

113.4130(10)

113.383(2)

90

90

90

V(Å )

1397.52

1389.88(14)

1383.1(3)

2661.4(2)

2647.9(14)

2642.2(8)

Z

1

1

1

4

4

4

Dcalc(g·cm )

1.656

1.684

1.696

1.684

1.697

1.709

Crystal size

0.44×0.32×0.19

0.59×0.31×0.15

0.51×0.32×0.29

0.59×0.37×0.19

0.49×0.27×0.18

0.44×0.32×0.21

704

708

710

1348

1352

1356

3

-3

(mm) F(000) µ(Mo-Kα)/mm

-1

1.919

2.180

2.335

2.557

2.736

2.893

θ (°)

1.67-25.00

1.68-21.86

1.68-28.38

1.67-25.76

1.67-25.00

1.68-25.00

Reflections

7075

5322

10314

13956

13752

13744

4871 (4599)

3337 (2924)

6879 (6491)

5086 (3936)

6610 (4108)

4396 (3821)

385

385

389

336

337

326

Collected Independent reflections (I > 2σ(I)) Parameters


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Limiting indices

-11

Functional Sensing Materials Based on Lanthanide N-heterocyclic

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