Metal complexes of sterically hindered pyrazolylpyridines. The single crystal X-ray structure of [Cu(L1)2]BF4 (L1=1-{pyrid-2-yl}-3-{2′,5′-dimethoxyphenyl} pyrazole)

Malcolm A. Halcrow, Natalie L. Cromhout, Paul R. Raithby

Research output: Contribution to journalArticlepeer-review

Abstract

Reaction of potassium 3{5}-(3′,4′-dimethoxyphenyl)pyrazolide with 2-bromopyridine in diglyme at 130°C for 3 days followed by an aqueous quench, affords 1-{pyrid-2-yl}-3-{3′,4′-dimethoxyphenyl}pyrazole (L2) in 69% yield after recrystallisation from hot hexanes. Complexation of [Cu(NCMe)4]BF4 by 2 molar equivalents of 1-{pyrid-2-yl}-3-{2′,5′-dimethoxyphenyl}pyrazole (L1) or L2 in MeCN at room temperature, followed by concentration and crystallisation with Et2O, gives [Cu(L)2]BF4 (L=L1, L2) in good yields. Treatment of AgBF4 with L1 or L2 in MeNO2 similarly gives [Ag(L)2]BF4 (L=L1, L2); reaction of AgBF4 with L2 in MeCN gives a product of stoichiometry [Ag(L2)(NCMe)]BF4. The 1H NMR spectra of the [M(L)2]BF4 complexes show peaks arising from a single coordinated ligand environment. The single crystal X-ray structure of [Cu(L1)2]BF4 shows a tetrahedral complex cation with Cu-N=2.011(8), 2.036(8), 2.039(8), 2.110(8) Å. The Cu1 centre is close to tetrahedral, the dihedral angle between the least-squares planes formed by the Cu atom and the N donor atoms of the two ligands being 88.3(3)°. Complexation of hydrated Cu(BF4)2 by L2 in MeCN at room temperature yields [Cu(L2)2](BF4)2. The cyclic voltammograms of the three Ag1 complexes in MeCN/0.1 M Bun4 NPF6 are suggestive of extensive ligand dissociation in this solvent.

Original languageEnglish
Pages (from-to)4257-4264
Number of pages8
JournalPolyhedron
Volume16
Issue number24
DOIs
Publication statusPublished - 15 Oct 1997

Keywords

  • Copper
  • Crystal structure
  • Pyrazolylpyridine
  • Silver

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry
  • Materials Chemistry

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