•A simple Schiff-based fluorescent probe 1 for Cu2 + was developed.•Highly selective in Cu2 + ion sensing with a large Stokes shift (146 nm)•Low detection limit for Cu2 + ion and 1:1 binding mode with Cu2 + ion•The probe 1 has been used in water samples.A new Schiff-base fluorescent probe 1 for the selective detection of Cu2 + has been synthesized by a simple one-step reaction of 1,3,3-trimethyl-2-(formylmethylene)indoline and diaminomaleonitrile. The probe 1 exhibited strong fluorescence enhancement with a large Stokes shift (146 nm) upon addition of Cu2 + and showed an excellent selectivity in the presence of competitive ions. The detection limit was found to be 6.18 × 10− 8 mol/L. The 1:1 binding mode of 1 with Cu2 + was supported by the Job's plot, 1H NMR and ESI-mass spectrometry analysis. Moreover, 1 also had the ability to quantify Cu2 + in actual water samples.A new “turn-on” Schiff-base fluorescent probe was synthesized by a simple one-step reaction, which has been successfully developed for the highly selective and sensitive detection of Cu2 + over other metal ions.Download high-res image (68KB)Download full-size image

A series of transition metal complexes with the ligands 3-pyrazoledicarboxylic acid (H2L1) and ethyl 1-(2-ethoxy-2-oxoethyl)-1H-pyrazole-3-carboxylate (epzc) have been synthesized. The epzc generated 1-(carboxymethyl)-1H-pyrazole-3-carboxylic acid (H2L2) by an in situ hydrothermal hydrolysis reaction, using a one-pot method. Simple mononuclear [Co(HL1)2(H2O)2] (1) and [Ni(L2)(H2O)4] (4), dinuclear [Ni2(L1)2(H2O)6]·H2O (2) and [Cu2(L2)2(H2O)4] (5) and 2D frameworks [Cu2(L1)2]n (3), [Co2(L2)2(H2O)4]n (6) have been isolated. The structures have been established by single-crystal X-ray diffraction, and the complexes characterized by FT-IR, thermogravimetric analysis (TGA), PRXD, UV–Vis spectroscopy, and fluorescent spectroscopy. 1, 2, 4 and 5 were further assembled to form a supramolecular structure by hydrogen-bonding interactions and/or π⋯π stacking. 3 and 6 both possess a 2D network structure that is further interlinked via intermolecular hydrogen-bonding interactions. Most importantly, the complexes demonstrated highly intense electrochemiluminescence (ECL) in DMF solution.

Two new precious metal coordination complexes [Pd(HL)2] (1) and [PtL2] (2) (where H2L is 1-(carboxymethyl)-1H-pyrazole-3-carboxylic acid) were synthesized by one-pot in situ hydrolysis. The complexes are assembled into a 3D structure by hydrogen bonding interactions and intermolecular contacts. The structures have been established by single-crystal X-ray diffraction, and characterized by FT-IR and liquid state fluorescent spectroscopy. Hirshfeld surface analysis reveals that the O···H contacts outnumber the other contacts in both structures (49.4 % of the total interactions for 1 and 41.6 % for 2).

Self-assembly through tuning the N-donor azole ligands and coordinative preferences of transition metal Cu(II), Cd(II) and Co(II) ions, three dimeric complexes, namely [Cu2(Hmpz)4(μ2-Cl)2Cl2] (1), [Cd2(pmtz)2Cl2(H2O)4] (2) and [Co2(Hmptz)2Cl2(H2O)4]Cl2·H2O (3) have been synthesized at solvent method and hydrothermal conditions and characterized by single crystal X-ray diffraction analyses and fluorescent property were investigated, where Hmpz = 3-methyl-1H-pyrazole, Hpmtz = 5-methyl-1-phenyl-1H-1,2,3-triazole-4-carboxylic acid, and H2mpta = 5-methyl-1-(1H-pyrazol-3-yl)-1H-1,2,3-triazole-4-carboxylic acid, respectively. In order to investigate the intermolecular contacts, Hirshfeld surface was studied in this work. The Hirshfeld surface analysis was successfully deployed here to visualize and elaborate the similarities and differences in the molecular environments of the three complexes.Three dimeric complexes were demonstrated in this work. In order to investigated the intermolecular interactions, Hirshfeld surface analysis was carried out on the title complexes.

One new trinuclear nickel(II) cluster with a Ni3(μ3-OH) core was synthesized by the method of in situ one pot synthesis. The complex [Ni3(μ3-OH)(cpza)3]Cl2·H2O (1) (where Hcpza is N-(4-cyano-1H-pyrazol-3-yl)acetamide) was characterized by single-crystal X-ray diffraction methods, elemental analyses, IR spectroscopy and Hirshfeld surface analysis. For complex 1, the crystal structure is extended into 3D structure through N–H···O and O–H···Cl hydrogen bonds. According to the 3D Hirshfeld surface and 2D fingerprint plots, the main interactions in the cluster are the H···H, N···H and O···H contacts.

One new trinuclear Fe(III) cluster with a Fe3(μ3-O) core was synthesized by the method of hydrothermal synthesis. The complex [Fe3(μ3-O)(pmta)6(H2O)3]FeCl4·2H2O (1) (where Hpmta is 5-methyl-1-phenyl-1H-1,2,3-triazole-4-carboxylic acid) was characterized by single-crystal X-ray diffraction methods, elemental analyses, IR spectroscopy, fluorescence and Hirshfeld surface analysis. For complex 1, the crystal structure is extended into 3D structure through N–H···O and O–H···O hydrogen bonds. According to the 3D Hirshfeld surface and 2D fingerprint plots, the main interactions in the cluster are the H···H, N···H and C···H contacts.

In the superbasic medium DMSO-KOH, bis(3,3-diethoxycarbonyl-1-pyrazolyl)methane (L) was synthesized. Besides, the single crystal of L has been obtained. Meanwhile, one novel coordination polymers, [Ag(L)(NO3)]n (1) was successfully prepared. The single X-ray diffraction data reveal that L crystallized in the P-1 space group. Novel bis(pyrazolyl)methane derivative ligand, L acts as multidentate ligands to coordinate with Ag ion to form a six-membered boat conformation. And furthermore the nitrate groups bridge each Ag(I) to construct a zigzag chain. The fluorescent properties of the complex were examined in solution and compared with the ligand. In order to investigate the intermolecular interactions, we also studied Hirshfeld surface analysis of ligand and the complex. The Hirshfeld surface analysis reveals that the main intermolecular interactions are H···H and O···H/H···O interactions which comprise 23.9 and 33.8 % of the total Hirshfeld surface area.

A highly selective chemodosimeter based on 1,8-naphthalimide for Pd2+/4+ species via a Claisen rearrangement was developed, which not only discriminated Pd from competing Pt species, but also distinguished Pd in an oxidized state without altering its oxidation states from Pd0. Under optimized reaction conditions, the detection limit can reach 1.4 μM for Pd2+.

•One 1D helical chain Cd(II) complex 1 constructed a 3D structure by hydrogen bonds.•Three Zn(II) complex 2–4 obtained by different Zn2+ salts with Hmptca.•Two in situ solvothermal decarboxylation complexes 4–5.•The fluorescent properties of crystalline complexes 1–5 investigated in solid-state.The complexes [CdCl(mptc)(H2O)2]n (1), Zn(mptc)(Hmptc)Br (2), {[Zn(mptc)3]2[Zn(H2O)6]·4H2O} (3) and Zn(mpt)2Cl2 (4) (mpt = 5-methyl-1-phenyl-1H-1,2,3-triazole) were prepared by 5-methyl-1-phenyl-1H-1,2,3-triazole-4-carboxylic acid (Hmptc) and Cd2+, Zn2+ respectively in different conditions. We found an interesting phenomenon of in situ decarboxylic reaction in complex 4. The same discovery was also in Zn(ipmt)2Br2 (5) (ipmt = 1-(4-iodophenyl)-5-methyl-1H-1,2,3-triazole), which was obtained by the reaction of 1-(4-iodophenyl)-5-methyl-1H-1,2,3-triazole-4-carboxylic acid (Hipmtc) with Zn2+ under solvothermal condition. And the crystal structures of 1–5 were determined via single-crystal X-ray diffraction. The complexes were characterized by FT-IR, elemental analyses, and solid-state fluorescent emission spectroscopy. Then, the possible mechanism of in situ solvothermal decarboxylation was discussed.In this paper, there are five complexes {Cd[mptc]Cl·2H2O}n (1), Zn[mptc]2Br (2), {[Zn(mptc)3]2[Zn(H2O)6]·4H2O} (3), Zn[mpt]2Cl2 (4), and Zn[ipmt]2Br2 (5) were prepared using 1,2,3-triazole derivatives and Cd2+, Zn2+ respectively in different conditions. We found an interesting phenomenon of in situ decarboxylation in complexes 4 and 5. The X-ray crystallographic analyses demonstrate the structure of complex 1–5. The complexes were characterized by FT-IR, elemental analyses and solid-state fluorescent emission spectroscopy.

The in situ hydrothermal reactions of 4-nitrobenzonitrile with Cd(ClO4)2 and CdCl2 afforded two novel CdII–tetrazole coordination polymers, 2D network {[Cd(H2O)2(4-nptz)2](H2O)2}n (1) and 1D double chains [Cd(H2O)2(4-nptz)2]n (2). Their synthesis, solid-state structure, and XRPD patterns are reported.

A series of transition metal complexes with the ligands 3-pyrazoledicarboxylic acid (H2L1) and ethyl 1-(2-ethoxy-2-oxoethyl)-1H-pyrazole-3-carboxylate (epzc) have been synthesized. The epzc generated 1-(carboxymethyl)-1H-pyrazole-3-carboxylic acid (H2L2) by an in situ hydrothermal hydrolysis reaction, using a one-pot method. Simple mononuclear [Co(HL1)2(H2O)2] (1) and [Ni(L2)(H2O)4] (4), dinuclear [Ni2(L1)2(H2O)6]·H2O (2) and [Cu2(L2)2(H2O)4] (5) and 2D frameworks [Cu2(L1)2]n (3), [Co2(L2)2(H2O)4]n (6) have been isolated. The structures have been established by single-crystal X-ray diffraction, and the complexes characterized by FT-IR, thermogravimetric analysis (TGA), PRXD, UV–Vis spectroscopy, and fluorescent spectroscopy. 1, 2, 4 and 5 were further assembled to form a supramolecular structure by hydrogen-bonding interactions and/or π⋯π stacking. 3 and 6 both possess a 2D network structure that is further interlinked via intermolecular hydrogen-bonding interactions. Most importantly, the complexes demonstrated highly intense electrochemiluminescence (ECL) in DMF solution.