Synthesis, crystal structures, and fluorescence properties of transition metal complexes derived from an unsymmetrical N-heterocyclic ligand

Abstract

Four transition metal complexes, [Mn(Hbimtz)₂(H₂O)₂(NCS)₂] (1), [Co(Hbimtz)₂(H₂O)₂(NCS)₂] (2), [Pb(Hbimtz)Br₂] _n (3), and {[Ag₂(Hbimtz)₃]SO₄ · 4H₂O} _n (4) (Hbimtz = 1-[(1H-benzimidazol-2-yl)-methyl]-1,2,3,4-tetrazole), were synthesized and characterized by single-crystal X-ray diffraction. The Mn(II) of 1 and Co(II) of 2 are six-coordinate with two nitrogen atoms from Hbimtz, two nitrogen atoms from thiocyanate and two water molecules. The geometry of Pb(II) in 3 is a distorted octahedron with two nitrogen atoms of two Hbimtz's and four Br⁻ ions, including the weak bond between the Pb1 and N6 of Hbimtz. Complex 3 is assembled into a 1-D [PbBr₂] _n inorganic chain by μ ₂-Br⁻ and into a 2-D layer by weak interactions. The Ag(II) of 4 has two geometries, linear and tetrahedral. Hbimtz bridges the two kinds of Ag(II) into a 1-D helical chain. Fluorescence of 3 and 4 were also investigated.

Keywords:

• Crystal structure
• 1-[(1H-benzimidazol-2-yl)-methyl]-1,2,3,4-tetrazole
• Transition metal complexes
• Photoluminescence properties

Acknowledgments

We gratefully acknowledge the Nature Science Foundation of China (No. 21061002), the Science Foundation of Guangxi (No. 2010GXNSFF013001 and 0832098), the project of Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources (Guangxi Normal University), Ministry of Education of China [CMEMR2011-20], and the Postgraduate Education Innovative Planning of Guangxi (2010106020703M69).