Metal Ion Binding Sites Composed of Multiple Nitrogenous Heterocycles. Synthesis and Spectral and Structural Study of Bis(2,2′,2″-tripyridylamine)copper(II) Bis(trifluoromethanesulfonate) and Its Bis(acetonitrile) Adduct

Patricia L. Dedert, Jeffery S. Thompson, James A Ibers*, Tobin Jay Marks

*Corresponding author for this work

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Abstract

The copper complex [Cu(N(py)3)2(CH3CN)2][SO3CF3]2, N(py)3 = 2,2′,2″-tripyridylamine, can be prepared by the reaction of Cu(SO3CF3)2 with N(py)3 in acetonitrile. The complex Cu(N(py)3)2(SO3CF3)2 can be prepared from Cu(SO3CF3)2 and N(py)3 in methanol or by recrystallizing the bis(acetonitrile) complex from acetone/ether. The bis(acetonitrile) complex crystallizes in the monoclinic space group C2h 5-P21/n with two molecules in a unit cell of dimensions a = 11.825 (2) Å, b = 14.774 (3) Å, c = 11.516 (2) Å, and β = 97.699 (4)°. Least-squares refinement of the 193 variables led to a value of the conventional R index (on F) of 0.070 for 1669 reflections having Fo 2 > 3σ(Fo 2). The geometry about the cupric ion is tetragonally distorted octahedral (crystallographically imposed symmetry 1̄) with two pyridyl rings from each bidentate N(py)3 ligand defining the equatorial coordination. The Cu(II) ion and four nitrogen atoms are rigorously coplanar, with an average Cu-N distance of 2.020 (3) Å. The acetonitrile ligands occupy axial ligation positions with a Cu-N distance of 2.526 (8) Å. The above complexes have been studied by infrared, optical, and EPR spectroscopy. The vibrational spectroscopic results in the N(py)3 and SO3CF3 skeletal regions are in accord with bidentate N(py)3 coordination in both compounds. For Cu(N(py)3)2(SO3CF3)2, axial triflate coordination is indicated. The optical and EPR spectral data are also in accord with these structural conclusions. For [Cu(N(py)3)2(CH3CN)2][SO3CF3]2, the 14N superhyperfine coupling shows the pyridyl and acetonitrile donors to be magnetically indistinguishable.

Original languageEnglish (US)
Pages (from-to)969-977
Number of pages9
JournalInorganic Chemistry
Volume21
Issue number3
DOIs
StatePublished - Jan 1 1982

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ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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