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Updated: Aug 29, 2025

A Novel Technique for Generating and Observing Chemiluminescence in a Biological Setting
Published on: March 9, 2017
Mononuclear, hexanuclear and polymeric indium(III) pyrazolido complexes; structural characterization, dynamic
Susana Herrera1, Kennett I Rivero2, Alexis Guzmán2
1Department of Chemistry and Biochemistry and Biomolecular Sciences Institute, Florida International University, Miami, FL 33199, USA. rraptis@fiu.edu.
Abstract:
A new family of six mononuclear indium(III) complexes of formula mer-[InIIICl3(pz*H)3]-pz*H = pyrazole (pzH), or substituted pyrazoles: 4-Cl-pzH, 4-Br-pzH, 4-I-pzH, 4-Ph-pzH and 3,5-Me2-pzH-were synthesized by addition reactions of InCl3 and pz*H and crystallographically characterized. The fluxional behaviour of the complexes, probed by variable temperature 1H NMR spectroscopy in the 328 K to 173 K range, was attributed to (at least) four simultaneous processes: pyrazole N-H proton dissociation/association, cis/trans-pyrazole exchange, and N1/N2 tautomerization of the cis- and of the trans-pyrazoles. Three novel trianionic hexanuclear complexes of general formula (pipH)3[In6Cl6(μ3-OH0.5)2(μ-OH)6(μ-pz*)6]-pz* = pz, 4-Cl-pz and 4-Ph-pz-showing μ-hydroxo and μ-oxo bridges were synthesized from the corresponding mer-[InIIICl3(pz*H)3] and characterized by single crystal X-ray diffraction and 1H NMR. Under different solvent conditions, multicolour emitting polymeric complexes of general formula [In(μ-pz*)3]-pz* = pz, 4-Cl-pz, 4-I-pz and 4-Ph-pz-were obtained also from mer-[InIIICl3(pz*H)3] after addition of a base. Luminescence and lifetime calculations were performed for all polymers formed.
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