English

• 0.   Introduction

  Since the Second World War, antibiotics have been instrumental in enhancing human health and bolstering animal husbandry production^[1-2]. As they can not be fully metabolized within the body, antibiotics are widely discharged from human and animal sources into the aquatic environment^[3-4]. They are also present in grains, groundwater, and animals, which significant- ly threatens human health and environmental safety^[5-6]. Ciprofloxacin (CIP) is the most active fluoroquinolone of the second generation of fluoroquinolones. It provides an effective treatment for a variety of infections, particularly those affecting the urinary, respiratory, gastrointestinal, skin, and soft tissue^[7]. In recent years, the importance of CIP as a specific drug in treating Bacillus anthracis infection has increased^[8]. Nevertheless, excessive CIP can result in significant adverse effects, including central nervous system disorders, hepatotoxicity, interstitial nephritis, and eosinophilia^[9]. In recent years, some mature methods for the detection of CIP have emerged, including capillary electrophoresis (CE), high-performance liquid chromatography (HPLC), spectrophotometry, and liquid chromatography-tandem mass spectrometry (LC-MS/MS) ^[10-13]. While these methods are accurate and have low detection limits, they are typically technically complex and necessitate the use of toxic reagents or an extended analysis time^[14-15]. Therefore, it is significant to establish a simple, reliable, and low-detection limit material for detecting CIP in urine.

  Coordination polymers (CPs) have great application prospects in adsorption and separation^[16-17], electrocatalysis^[18], drug delivery^[19-20], supercapacitors, and fluorescent sensors^[21-22] due to their unique topological structure and fascinating properties. It is noteworthy that CPs can function as luminescent sensors, exhibiting different degrees of luminescence modulation (enhancement or quenching) upon interaction with a host molecule^[23]. These properties have garnered considerable attention, given the advantages of their fast response time, high sensitivity, and straightforward preparation. At present, a considerable number of luminescent sensors based on coordination complexes have been designed and synthesized^[24-25]. However, the majority of these sensors are employed for the detection of metal anions/cations, small molecules, explosives, and pH levels^[26-28]. Conversely, there is a paucity of fluorescent sensors for detecting antibiotics^[29-30]. Moreover, although numerous CPs have been employed in the fluorescence sensing of CIP, the detection limit remains relatively low. It is therefore of great significance to design and synthesize a fluorescence sensor with a high detection limit.

  Herein, via the flexible ligand 5, 5'-[(5-carboxy-1, 3-phenyl)bis(oxy)]triisophthalic (H₅cpbda) with N - donor ligands 2, 2'-bipy(2, 2'-bipyridine)/phen(1, 10-phenanthroline) and transition metal Cd²⁺/Mn²⁺. We have successfully synthesized and characterized two coordination polymers, [Cd(H₃cpbda)(2, 2'-bipy)(H₂O)]_n (1) and [Mn(H₃cpbda)(phen)(H₂O)]_n (2) (Scheme 1). Complex 1 displayed remarkable chemical stability in aqueous solution. The results of luminescence sensing experiments demonstrated that the fluorescence of 1 exhibited an exceptionally high degree of sensitivity to CIP.

  Scheme 1

  

  Scheme 1.  Synthetic routes of complexes 1 and 2

  下载: 全尺寸图片 幻灯片

  1.   Experimental

  1.1   Materials and methods

  H₅cpbda was obtained from Jinan Trading Company, China. Other reagents and solvents were purchased from commercial sources. X-ray diffraction (XRD) patterns were measured on a Bruker D8 Advance X-ray diffractometer using Cu Kα (λ = 0.154 184 nm) radiation at 25 ℃ and recorded on crushed single crystals in the range of 5° - 50°. The operating voltage and current were 40 kV and 25 mA, respectively. TGA (thermogravimetric analyses) were performed in the temperature range of 25-500 ℃ under an N₂ atmosphere with a heating rate of 10 ℃ ·min^-1. FTIR was measured with Bruker TENSOR27 spectrometer and recorded with KBr particles in 400 - 4 000 cm^-1. The fluorescence spectra were recorded on an FS5 fluorescence spectrophotometer with a quartz cuvette (path length of 1 cm). UV-Vis absorption spectra were determined on a spectrophotometer UV-2450.

  1.2   Synthesis of complex 1

  Cd(NO₃)₂·4H₂O (30.8 mg, 0.1 mmol), H₅cpbda (24.1 mg, 0.05 mmol), 2, 2'-bipy (15.62 mg, 0.10 mmol) in an 8 mL solution of methanol and water (1∶1, V/V) were added to a 24 mL Teflon lined autoclave. Subsequently, after stirring for 30 min, the mixture should be heated in an oven set to 160 ℃ for 72 h. Once the solution had cooled to room temperature, the colorless bulk crystals were obtained by filtration. The complex 1 was then obtained by washing with water. Yield: 67% (based on H₅cpbda). Elemental analysis(%) Calcd.(Found) for C₃₃H₂₂CdN₂O₁₃: C 51.68 (51.39); H 2.89 (2.83); N 3.65 (3.72). IR (KBr, cm^-1): 3 992 m, 1 709 m, 1 644 m, 1 566 s, 1 349 m, 1 369 s, 1 241 w, 1 130 m, 1 022 m, 1 013 m, 898 w, 756 s, 640 w.

  1.3   Synthesis of complex 2

  A mixture of H₅cpbda (48.2 mg, 0.1 mmol), MnSO₄·H₂O (25.40 mg, 0.15 mmol), phen (29.70 mg, 0.15 mmol), and a solvent mixture of CH₃CN (5 mL), H₂O (5 mL) were added into a 24 mL Teflon - lined stainless autoclave and heated at 160 ℃ for 72 h. Pale yellow bulk crystals were collected by filtration, washed with water, and dried in air (yield 48%, based on H₅cpbda). Elemental analysis(%): Calcd. (Found) for C₃₅H₂₂MnN₂O₁₃: C 57.31 (57.29); H 3.02 (2.95); N 3.82 (3.87). IR (KBr, cm^-1): 3 404 w, 1 706 w, 1 622 s, 1 574 s, 1 384 s, 1 244 m, 1 136 m, 1 013 m, 843 m, 781 m, 724 m, 635 w.

  1.4   Crystal structure determination

  The single-crystal data of complexes 1 and 2 were collected on a Bruker D8-Quest diffractometer equipped with a Photon 100 detector by using graphite monochromated Mo Kα radiation (λ=0.071 073 nm) at 293(2) - 298(2) K. Absorption corrections were applied by using multi-scan of the SADABS program. The crystal structures were solved and refined using the Olex2 program. All the non - hydrogen atoms were refined anisotropically. H atoms attached to C atoms were placed geometrically and refined using a riding-model approximation, with d_C—H=0.095 nm and U_iso(H)=1.2U_eq (C). H atoms attached to O atoms were located from difference Fourier maps, and their bond lengths were restrained in a range of 0.082 70 - 0.084 64 nm; then, they were refined using a riding model, with U_iso(H) =1.5U_eq(O). Crystal data and structure refinement parameters are summarized in Table 1. Selected bond distances (nm) and angles (°) are displayed in Table 2.

  Table 1

  

  Table 1.  Crystal data and structure refinement details for complexes 1 and 2

  下载: 导出CSV

  Parameter	1	2
  Formula	C33H22CdN2O13	C35H22MnN2O13
  Formula weight	766.92	733.48
  Crystal system	Monoclinic	Triclinic
  Space group	P21/n	$P\overline 1 $
  Temperature/K	298(2)	298(2)
  a/nm	0.958 8(9)	0.854 2(14)
  b/nm	2.646 2(3)	0.860 8(12)
  c/nm	1.185 9(12)	0.860 8(12)
  α/(°)		68.617(6)
  β/(°)	100.223(3)	78.709(6)
  γ/(°)		78.709(6)
  V/nm3	2.961 1(5)	0.726 9(2)
  Z	4	1
  Dc/(Mg·m-3)	1.716	1.676
  μ/mm-1	0.82	0.54
  Rint	0.073	0.040
  GOF	1.03	1.07
  F(000)	1 536	375
  R1 [I>2σ(I)]	0.049	0.041
  wR2 [I>2σ(I)]	0.139	0.082

  Table 2

  

  Table 2.  Selected bond lengths (nm) and bond angles (°) of complexes 1 and 2

  下载: 导出CSV

  1
  Cd1—N1	0.235 5(3)	Cd1—O1	0.215 2(3)	Cd1—O13	0.223 6(3)
  Cd1—N2	0.227 1(3)	Cd1—O5i	0.216 8(3)
  N2—Cd1—N1	71.20(12)	O1—Cd1—O13	104.61(14)	O13—Cd1—N1	151.61(15)
  O1—Cd1—N1	103.78(11)	O5i—Cd1—N1	81.92(12)	O13—Cd1—N2	90.48(14)
  O1—Cd1—N2	130.04(12)	O5i—Cd1—N2	132.91(13)
  O1—Cd1—O5i	93.06(13)	O5i—Cd1—O13	96.36(11)
  2
  Mn1—O1	0.208 4(2)	Mn1—O13	0.220 8(3)	Mn1—N2	0.223 1(3)
  Mn1—O7i	0.208 8(2)	Mn1—N1	0.226 0(3)
  O1—Mn1—O7i	106.19(9)	O7i—Mn1—O13	88.63(9)	O13—Mn1—N2	134.81(10)
  O1—Mn1—O13	90.91(10)	O7i—Mn1—N1	92.63(9)	N2—Mn1—N1	73.86(10)
  O1—Mn1—N1	160.39(9)	O7i—Mn1—N2	134.52(10)
  O1—Mn1—N2	88.70(9)	O13—Mn1—N1	95.08(10)
  Symmetry codes: i x+1/2, -y+1/2, z+1/2 for 1; i x, y-1, z+1 for 2.

  2.   Results and discussion

  2.1   Crystal structure

  Complex 1 crystallizes in a monoclinic system with a P2₁/n space group. The asymmetric unit of 1 contains one Cd²⁺ ion, one H₃cpbda^2- ligand, a chelating 2, 2' - bipy ligand, and one coordinated H₂O molecule. As shown in Fig. 1a, the five-coordinated Cd1 center exhibits a distorted square pyramidal geometry with the [CdO₃N₂] structure, which is two carboxyl oxygen atoms (O1 and O5ⁱ) from two H₃cpbda^2- ligands, one oxygen from lattice water and two nitrogen atoms (N1 and N2) from one 2, 2'-bipy molecule. The Cd—O distances are in a range 0.215 2(3)-0.223 6(3) nm, and the O—Cd—O angles vary from 93.06(13)° to 104.61(14)°. The Cd—N bond lengths are 0.227 1(3) and 0.235 5(3) nm. In complex 1, each H₃cpbda^2- ligand acts as one μ₂-κ²O¹∶O¹ mode to coordinate with two Cd ions to form a tortuous 1D chain structure. The Cd…Cd distance is 1.086 3(1) nm (Fig. 1b). In addition, there are weak π … π stacking interactions between the pyridine rings and pyridine rings with a centroid…centroid distance of 0.383 6(3) nm. The 1D chains are further extended by these weak π…π interactions to 2D supramolecular structures (Fig. 1c).

  Figure 1

  

  Figure 1.  (a) Coordination mode of Cd²⁺, (b) 1D chain, and (c) perspective view of the 2D structure by π…π interactions of complex 1

  Coordination mode of Cd²⁺ at 30% thermal ellipsoids; Symmetry code: ⁱx+1/2, -y+1/2, z+1/2.

  下载: 全尺寸图片 幻灯片

  Single crystal X-ray diffraction shows that complex 2 crystallizes in the triclinic system, space group $P\overline 1 $. Its asymmetric unit consists of one Mn²⁺ ion, one H₃cpbda^2- ligand, one phen ligand, and one coordinated H₂O molecule. As shown in Fig. 2a, the Mn²⁺ ion is coordinated by three oxygen atoms (O1, O7, and O13) from two H₃cpbda^2- ligands and one coordinated H₂O molecule, as well as two N atoms from one phen ligand, showing a distorted pentagonal {MnO₃N₂} geometry. The Mn—O distances are in a range of 0.208 4(2)-0.220 8(3) nm and the Mn—N distances are 0.226 0(3) and 0.223 1(3) nm with O—Mn—O angles of 88.63(9)°- 106.19(9)°.

  Figure 2

  

  Figure 2.  (a) Coordination environment of Mn²⁺ ions, (b) 1D chain, and (c) perspective view of the 2D structure by π…π interactions of complex 2

  Coordination environment of Mn²⁺ ions at 30% thermal ellipsoids; Symmetry code: ⁱx, y-1, z+1.

  下载: 全尺寸图片 幻灯片

  The H₅cpbda ligand in complex 2 is partially deprotonated. Each H₃cpbda^2- ligand links two Mn²⁺ ions with a μ₂-(κ¹-κ⁰)-(κ⁰-κ⁰)-(κ¹-κ⁰)-(κ⁰-κ⁰)-(κ⁰-κ⁰) mode, forming a 1D network (Fig. 2b). In addition, a 3D network structure with a distance of 0.379 2 and 0.360 5 nm are formed between adjacent layers by π… π stacking interactions between the phen and H₃cpbda^2- ligand (Fig. 2c).

  2.2   XRD and thermal stability

  To ascertain the purity of the samples of complexes 1 and 2, the XRD patterns of 1 and 2 were determined. As shown in Fig. S1 (Supporting information), the XRD patterns are in satisfactory alignment with the simulated data derived from single - crystal diffraction outcomes, which indicates that all complexes exhibit high phase purity. TGA investigated the thermal stability of complexes 1 and 2 at a heating rate of 10 ℃·min^-1 from room temperature to 500 ℃ in a N₂ atmosphere. As illustrated in Fig. 3a, the TGA curve within the temperature range of 70-130 ℃ exhibited a total weight loss of 2.76%, which is equivalent to the loss of one H₂O molecule (Calcd. 2.35%), and then remained stable. The remaining solid began to decompose at 345 ℃. The TGA curve of 2 in the 25 - 95 ℃ range showed a total loss of 2.57%, which also corresponds to the release of one H₂O molecule (Calcd. 2.45%). Then, the framework underwent decomposition after 350 ℃ (Fig. 3b).

  Figure 3

  

  Figure 3.  TGA curves of complexes (a) 1 and (b) 2

  下载: 全尺寸图片 幻灯片

  2.3   Detection of CIP

  Coordination polymers containing d¹⁰ electrons have attracted considerable attention due to their diverse functions and potential applications, and the excessive use of CIP has caused hepatotoxicity, eosinophilia, and central nervous system disorders. In light of this, we proposed the use of complex 1 for the detection of excessive CIP in urine. Complex 1 demonstrated photoluminescence with the peak emission at 325 nm under 295 nm excitation and the emission intensity of the suspension of complex 1 has been demonstrated to exhibit long-term high stability (Fig. 4a). Consequently, the ability of the complex to detect CIP in urine was investigated. The principal constituents of human urine are water, KCl, NaCl, NH₄Cl, Na₂SO₄, glucose, urea, creatine, and creatinine. A series of experiments was conducted to investigate whether complex 1 could be used to detect CIP in urine. As shown in Fig. 4b, the fluorescence intensity of complex 1 did not change signifi- cantly when different urine components of 10^-3 mol·L^-1 were added. However, when CIP was added, the fluorescence intensity of complex 1 decreased significantly and an obvious absorption peak appeared at 436 nm.

  Figure 4

  

  Figure 4.  (a) Fluorescence intensity changes with time, (b) fluorescence spectra with different components (10^-3 mol·L^-1, 100 μL) in human urine, and (c) effect of the concentration of CIP on the fluorescence intensity, (d) Stern⁃Volmer plots for CIP solution of complex 1

  下载: 全尺寸图片 幻灯片

  To understand the luminescence quenching in the presence of CIP, the luminescence quenching of the complex in the case of increasing CIP concentration was studied. As shown in Fig. 4c, with the increase of CIP concentration, the fluorescence of complex 1 at 325 nm gradually decreased, while the fluorescence at 436 nm gradually increased. The fluorescence quenching of complex 1 was analyzed by Stern-Volmer equation I₀/I=1+K_SVc_M, where I₀ and I are the emission intensities at 325 nm in the absence or presence of analytes, respectively, K_SV represents the quenching constant, and c_M is the concentration of the analytes. The Stern- Volmer plots for CIP are almost linear at low concentrations, with a correlation coefficient of 0.991 5. The quenching constants K_SV were calculated to be 2.71×10⁷ L·mol^-1 for CIP (Fig. 4d). The detection limit (LOD) of CIP was calculated by the formula LOD=3σ/k, where σ is the standard deviation of the five blank measurements of complex 1 and k is the slope of the linear curve plotted by LOD at a lower concentration. The LOD value for CIP was 1.91×10^-8 mol·L^-1, which represents a significant improvement over the majority of previously reported MOFs (metal-organic frameworks)-based fluorescent chemosensors for the detection of CIP (Table S1).

  To investigate the impact of additional components present in urine on the detection of CIP, we conducted a series of experiments examining the fluorescence spectrum of CIP in the presence of a range of other urine components. As illustrated in Fig. 5, the fluorescence intensity of complex 1 exhibited minimal variation when other components present in urine were introduced. Conversely, a notable decline in fluorescence intensity was observed when CIP was added, suggesting that the suspension of complex 1 demonstrated an effective anti-interference capacity.

  Figure 5

  

  Figure 5.  Interference of different urine components in a solution with CIP

  下载: 全尺寸图片 幻灯片

  The sensing mechanism of the complexes was discussed. As illustrated in Fig. S2, the XRD patterns of complex 1 following soaking in the analyte exhibits a high degree of correlation with the XRD patterns of the original sample. This observation suggests that the destruction of the skeleton does not represent the primary mechanism responsible for the observed luminescence change. Subsequently, the UV - Vis absorption spectrum of CIP coincides with the excitation wavelength of complex 1, thereby indicating that the primary factor responsible for the observed fluorescence quenching is the energy absorption of CIP (Fig.S3).

  3.   Conclusions

  In summary, based on the H₅cpbda ligand, two novel coordination polymers were designed and synthesized by adjusting the metal and N-donor ligands. The structural analysis shows that complexes 1 and 2 are 1D chain structures and the 1D chains are further extended by these weak π…π interactions to 2D and 3D supramolecular structures, respectively. The luminescent properties demonstrate that complex 1 is an exceptionally effective quenching sensor for the detection of CIP in urine, with a detection limit of 1.91×10^-8 mol·L^-1. This work provides a new perspective and idea for the detection of antibiotics by complexes.

  
  Supporting information is available at http://www.wjhxxb.cn
  
• 1. [1]

     Johnson A C, Keller V, Dumont E, Sumpter J P. Assessing the concentrations and risks of toxicity from the antibiotics ciprofloxacin, sulfamethoxazole, trimethoprim and erythromycin in European rivers[J]. Sci. Total Environ., 2015, 511:  747-755. doi: 10.1016/j.scitotenv.2014.12.055

  2. [2]

     Wang B H, Yan B. A turn-on fluorescence probe Eu³⁺ functionalized Ga-MOF integrated with logic gate operation for detecting ppm-level ciprofloxacin (CIP) in urine[J]. Talanta, 2020, 208:  120438. doi: 10.1016/j.talanta.2019.120438

  3. [3]

     Yang D D, Shi Y S, Xiao T, Fang Y H, Zheng X J. Three-dimensional viologen based lanthanide organic frameworks: Photochromism and fluorescence detection of quinolone antibiotics[J]. Inorg. Chem., 2023, 62:  6084-6091. doi: 10.1021/acs.inorgchem.3c00065

  4. [4]

     Segura P A, Takada H, Correa J A, El Saadi K, Koike T, Onwona A S, Ofosu A J, Sabi E B, Wasonga O V, Mghalu J M, Dos A M, Newman B, Weerts S, Yargeau V. Global occurrence of anti-infectives in contaminated surface waters: Impact of income inequality between countries[J]. Environ. Int., 2015, 80:  89-97. doi: 10.1016/j.envint.2015.04.001

  5. [5]

     Yan C X, Yang Y, Zhou J L, Liu M, Nie M H, Shi H, Gu L J. Antibiotics in the surface water of the Yangtze Estuary: Occurrence, distribution and risk assessment[J]. Environ. Pollut., 2013, 175:  22-29. doi: 10.1016/j.envpol.2012.12.008

  6. [6]

     Pan M, Chu L M. Fate of antibiotics in soil and their uptake by edible crops[J]. Sci. Total Environ., 2017, 599/600:  500-512. doi: 10.1016/j.scitotenv.2017.04.214

  7. [7]

     Lai Z Z, Yang X, Qin L, An J L, Wang Z, Sun X, Zhang M D. Synthesis, dye adsorption, and fluorescence sensing of antibiotics of a zincbased coordination polymer[J]. J. Solid State Chem., 2021, 300:  122278. doi: 10.1016/j.jssc.2021.122278

  8. [8]

     Xiao J N, Liu M Y, Tian F L, Liu Z L. Stable Europium-based metalorganic frameworks for naked-eye ultrasensitive detecting fluoroquinolones antibiotics[J]. Inorg. Chem., 2021, 60:  5282-5289. doi: 10.1021/acs.inorgchem.1c00263

  9. [9]

     Jalal N R, Madrakian T, Afkhami A, Ghamsari M. Polyethylenimine@Fe₃O₄@carbon nanotubes nanocomposite as a modifier in glassy carbon electrode for sensitive determination of ciprofloxacin in biological samples[J]. J. Electroanal. Chem., 2019, 833:  281-289. doi: 10.1016/j.jelechem.2018.12.004

  10. [10]

      Janusch F, Scherz G, Mohring S A, Hamscher G. Determination of fluoroquinolones in chicken feces-A new liquid liquid extraction method combined with LC MS/MS[J]. Environ. Toxicol. Pharmacol., 2014, 38(3):  792-799. doi: 10.1016/j.etap.2014.09.011

  11. [11]

      Vybíralová Z, Nobilis M, Zoulova J, Květina J, Petr P. High-performance liquid chromatographic determination of ciprofloxacin in plasma samples[J]. J. Pharm. Biomed. Anal., 2005, 37:  851-858. doi: 10.1016/j.jpba.2004.09.034

  12. [12]

      Pascual-Reguera M, Parras G P, Dıaz A M. Solid-phase UV spectrophotometric method for determination of ciprofloxacin[J]. Microchem J., 2004, 77:  79-84. doi: 10.1016/j.microc.2004.01.003

  13. [13]

      Xu X Y, Liu L H, Jia Z M, Shu Y. Determination of enrofloxacin and ciprofloxacin in foods of animal origin by capillary electrophoresis with field amplified sample stacking sweeping technique[J]. Food Chem., 2015, 176:  219-225. doi: 10.1016/j.foodchem.2014.12.054

  14. [14]

      Dil E A, Ghaedi M, Asfaram A. Application of hydrophobic deep eutectic solvent as the carrier for ferrofluid: A novel strategy for preconcentration and determination of mefenamic acid in human urine samples by high performance liquid chromatography under experimental design optimization[J]. Talanta, 2019, 202:  526-530. doi: 10.1016/j.talanta.2019.05.027

  15. [15]

      Mehrabi F, Vafaei A, Ghaedi M, Ghaedi A M, Dil E A, Asfaram A. Ultrasound assisted extraction of Maxilon Red GRL dye from water samples using cobalt ferrite nanoparticles loaded on activated carbon as sorbent: Optimization and modeling[J]. Ultrason. Sonochem., 2017, 38:  672-680. doi: 10.1016/j.ultsonch.2016.08.012

  16. [16]

      Xu X Y, Yan B. An efficient and sensitive fluorescent pH sensor based on amino functional metal-organic frameworks in aqueous environment[J]. Dalton Trans., 2016, 45:  7078-7084. doi: 10.1039/C6DT00361C

  17. [17]

      Lu Y, Yan B. A ratiometric fluorescent pH sensor based on nanoscale metal-organic frameworks (MOFs) modified by europium(Ⅲ)complexes[J]. Chem. Commun., 2014, 50:  13323-13326. doi: 10.1039/C4CC05508J

  18. [18]

      Abdelhamid H N, BermejoGómez A, Martín-Matute B, Zou X. A water stable lanthanide metal organic framework for fluorimetric detection of ferric ions and tryptophan[J]. Microchim. Acta, 2017, 184:  3363-3371. doi: 10.1007/s00604-017-2306-0

  19. [19]

      Wang B, Yang Q, Guo C, Sun Y X, Xie L H, Li J R. Stable Zr (Ⅳ)-based metal organic frameworks with predesigned functionalized ligands for highly selective detection of Fe (Ⅲ) ions in water[J]. ACS Appl. Mater. Interfaces, 2017, 9:  10286-10295. doi: 10.1021/acsami.7b00918

  20. [20]

      Li L, Zhu Y L, Zhou X H, Brites C D, Ananias D, Lin Z, Paz F A, Rocha J, Huang W, Carlos L D. Visible light excited luminescent thermometer based on single lanthanide organic frameworks[J]. Adv. Funct. Mater., 2016, 26:  8677-8684. doi: 10.1002/adfm.201603179

  21. [21]

      刘露, 王慧杰, 王海童, 李英. 二维Cd (Ⅱ)配合物的晶体结构及其对对硝基苯酚、四环素、2, 6-二氯-4-硝基苯胺的荧光识别[J]. 无机化学学报, 2024,40,(6): 1180-1188. doi: 10.11862/CJIC.20230489LIU L, WANG H J, WANG H T, LI Y. Crystal structure of a two dimensional Cd (Ⅱ) complex and its fluorescence recognition of p nitrophenol, tetracycline, 2, 6 dichloro 4 nitroaniline[J]. Chinese J. Inorg. Chem., 2024, 40(6):  1180-1188. doi: 10.11862/CJIC.20230489

  22. [22]

      张欢, 王记江, 范广, 唐龙, 岳二林, 白超, 王潇, 张玉琦. 一种用于检测四环素和对硝基苯酚的高稳定性镉(Ⅱ)金属有机骨架[J]. 无机化学学报, 2024,40,(3): 646-654. doi: 10.11862/CJIC.20230291ZHANG H, WANG J J, FAN G, TANG L, YUE E, BAI C, WANG X, ZHANG Y Q. A highly stable cadmium (Ⅱ) metal-organic framework for detecting tetracycline and p-nitrophenol[J]. Chinese J. Inorg. Chem., 2024, 40(3):  646-654. doi: 10.11862/CJIC.20230291

  23. [23]

      Liu X X, Yang D D, Feng S S, Lu L P. Dual-function Cd (Ⅱ) coordination complexes as sensors for efficient detection of Zn²⁺ and Tb³⁺ ions[J]. J. Lumin., 2022, 252:  119426. doi: 10.1016/j.jlumin.2022.119426

  24. [24]

      Liu J, Goetjen T A, Wang Q, Knapp J G, Wasson M C, Yang Y, Syed Z H, Delferro M, Notestein J M, Farha O K, Hup J T. MOF-enabled confinement and related effects for chemical catalyst presentation and utilization[J]. Chem. Soc. Rev., 2022, 51:  1045-1097. doi: 10.1039/D1CS00968K

  25. [25]

      Amooghin E A, Sanaeepur H, Luque R, Garcia H, Chen B L. Fluorinated metal-organic frameworks for gas separation[J]. Chem. Soc. Rev., 2022, 51:  7427-7508. doi: 10.1039/D2CS00442A

  26. [26]

      Jiang X L, Jiao Y E, Hou S L, Geng L C, Wang H Z, Zhao B. Green conversion of CO₂ and propargylamines triggered by triply synergistic catalytic effects in metal-organic frameworks[J]. Angew. Chem. Int. Ed., 2021, 60:  20417-20423. doi: 10.1002/anie.202106773

  27. [27]

      Gu A L, Zhang Y X, Wu Z L, Cui H Y, Hu T D, Zhao B. Highly efficient conversion of propargylic alcohols and propargylic amines with CO₂ activated by noble metal free catalyst Cu₂O@ZIF-8[J]. Angew. Chem. Int. Ed., 2022, 61:  e202114817. doi: 10.1002/anie.202114817

  28. [28]

      Huxford R C, DeKrafft K E, Boyle W S, Liu D M, Lin W B. Lipidcoated nanoscale coordination polymers for targeted delivery of antifolates to cancer cells[J]. Chem. Sci., 2012, 3:  198-204. doi: 10.1039/C1SC00499A

  29. [29]

      Zeng N N, Ren L, Cui G H. Ultrasensitive fluorescence detection of norfloxacin in aqueous medium employing a 2D Zn (Ⅱ)-based coordination polymer[J]. CrystEngComm, 2022, 24:  931-935. doi: 10.1039/D1CE01537K

  30. [30]

      Yu M K, Xie Y, Wang X Y, Li Y X, Li G M. Highly waterstable Dye@Ln-MOFs for sensitive and selective detection toward antibiotics in water[J]. ACS Appl. Mater. Interfaces, 2019, 11:  21201-21210. doi: 10.1021/acsami.9b05815

• 

  Scheme 1  Synthetic routes of complexes 1 and 2

  下载: 全尺寸图片 幻灯片
  

  Figure 1  (a) Coordination mode of Cd²⁺, (b) 1D chain, and (c) perspective view of the 2D structure by π…π interactions of complex 1

  Coordination mode of Cd²⁺ at 30% thermal ellipsoids; Symmetry code: ⁱx+1/2, -y+1/2, z+1/2.

  下载: 全尺寸图片 幻灯片
  

  Figure 2  (a) Coordination environment of Mn²⁺ ions, (b) 1D chain, and (c) perspective view of the 2D structure by π…π interactions of complex 2

  Coordination environment of Mn²⁺ ions at 30% thermal ellipsoids; Symmetry code: ⁱx, y-1, z+1.

  下载: 全尺寸图片 幻灯片
  

  Figure 3  TGA curves of complexes (a) 1 and (b) 2

  下载: 全尺寸图片 幻灯片
  

  Figure 4  (a) Fluorescence intensity changes with time, (b) fluorescence spectra with different components (10^-3 mol·L^-1, 100 μL) in human urine, and (c) effect of the concentration of CIP on the fluorescence intensity, (d) Stern⁃Volmer plots for CIP solution of complex 1

  下载: 全尺寸图片 幻灯片
  

  Figure 5  Interference of different urine components in a solution with CIP

  下载: 全尺寸图片 幻灯片

  Table 1.  Crystal data and structure refinement details for complexes 1 and 2

  Parameter	1	2
  Formula	C33H22CdN2O13	C35H22MnN2O13
  Formula weight	766.92	733.48
  Crystal system	Monoclinic	Triclinic
  Space group	P21/n	$P\overline 1 $
  Temperature/K	298(2)	298(2)
  a/nm	0.958 8(9)	0.854 2(14)
  b/nm	2.646 2(3)	0.860 8(12)
  c/nm	1.185 9(12)	0.860 8(12)
  α/(°)		68.617(6)
  β/(°)	100.223(3)	78.709(6)
  γ/(°)		78.709(6)
  V/nm3	2.961 1(5)	0.726 9(2)
  Z	4	1
  Dc/(Mg·m-3)	1.716	1.676
  μ/mm-1	0.82	0.54
  Rint	0.073	0.040
  GOF	1.03	1.07
  F(000)	1 536	375
  R1 [I>2σ(I)]	0.049	0.041
  wR2 [I>2σ(I)]	0.139	0.082

  下载: 导出CSV

  Table 2.  Selected bond lengths (nm) and bond angles (°) of complexes 1 and 2

  1
  Cd1—N1	0.235 5(3)	Cd1—O1	0.215 2(3)	Cd1—O13	0.223 6(3)
  Cd1—N2	0.227 1(3)	Cd1—O5i	0.216 8(3)
  N2—Cd1—N1	71.20(12)	O1—Cd1—O13	104.61(14)	O13—Cd1—N1	151.61(15)
  O1—Cd1—N1	103.78(11)	O5i—Cd1—N1	81.92(12)	O13—Cd1—N2	90.48(14)
  O1—Cd1—N2	130.04(12)	O5i—Cd1—N2	132.91(13)
  O1—Cd1—O5i	93.06(13)	O5i—Cd1—O13	96.36(11)
  2
  Mn1—O1	0.208 4(2)	Mn1—O13	0.220 8(3)	Mn1—N2	0.223 1(3)
  Mn1—O7i	0.208 8(2)	Mn1—N1	0.226 0(3)
  O1—Mn1—O7i	106.19(9)	O7i—Mn1—O13	88.63(9)	O13—Mn1—N2	134.81(10)
  O1—Mn1—O13	90.91(10)	O7i—Mn1—N1	92.63(9)	N2—Mn1—N1	73.86(10)
  O1—Mn1—N1	160.39(9)	O7i—Mn1—N2	134.52(10)
  O1—Mn1—N2	88.70(9)	O13—Mn1—N1	95.08(10)
  Symmetry codes: i x+1/2, -y+1/2, z+1/2 for 1; i x, y-1, z+1 for 2.

  下载: 导出CSV
•