Regulation of the Metal Center and Coordinating Anion of Mononuclear Ln(III) Complexes to Promote an Efficient Luminescence Response to Various Organic Solvents

Hui-Feng Wang; Xiong-Feng Ma; Zhong-Hong Zhu; Hua-Hong Zou; Fu-Pei Liang

doi:10.1021/acs.langmuir.9b02990

Regulation of the Metal Center and Coordinating Anion of Mononuclear Ln(III) Complexes to Promote an Efficient Luminescence Response to Various Organic Solvents

Langmuir. 2020 Feb 18;36(6):1409-1417. doi: 10.1021/acs.langmuir.9b02990. Epub 2020 Feb 10.

Authors

Hui-Feng Wang¹, Xiong-Feng Ma¹, Zhong-Hong Zhu¹, Hua-Hong Zou¹, Fu-Pei Liang^{1

2}

Affiliations

¹ State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources , School of Chemistry and Pharmacy of Guangxi Normal University , No. 15 Yucai Road , Qixing District, Guilin 541004 , P. R. China.
² Guangxi Key Laboratory of Electrochemical and Magnetochemical Functional Materials, College of Chemistry and Bioengineering , Guilin University of Technology , No. 12 Jiangan Road , Qixing District, Guilin 541004 , P. R. China.

PMID: 32037836
DOI: 10.1021/acs.langmuir.9b02990

Abstract

A series of mononuclear lanthanide complexes [Ln(L1)(NO₃)₃], (Ln = Dy(III), 1; Tb(III), 3; and Eu(III), 4; L1 = (N¹E,N²E)-N¹,N²-bis((1-methyl-1H-benzo[d]imidazol-2-yl)methylene)cyclohexane-1,2-diamine) is obtained by reacting N-methylbenzimidazole-2-carbaldehyde (L2) and 1,2-cyclohexanediamine (L3) with Ln(NO₃)₃·6H₂O under solvothermal conditions. L1 ligand is produced via an in situ Schiff base reaction of two molecules of L2 and one molecule of L3. The metal center Ln(III) is in a N₄O₆ environment formed by L1 and NO₃^-. NaSCN is added on the basis of 1 synthesis. One SCN^- replaces one of the three coordinated NO₃^- anions in the 1 structure, and the complex [Dy(L1)(NO₃)₂(SCN)]·CH₃CN (2) is synthesized. The complex 1 shows excellent luminescence response to petroleum ether (PET), an organic solvent. To the best of our knowledge, this study is the first to use a complex for sensing responses to PET. When the metal center is changed, the obtained mononuclear complexes 3 and 4 show an excellent luminescence response to tetrahydrofuran (THF). Lastly, 2 obtained by changing the coordinating anion shows an excellent luminescence response to dichloromethane. Herein, for the first time, we regulate the metal center and coordinating anion of lanthanide complexes to adjust the recognition and response of these complexes to different organic solvents.