Replacing mercury: syntheses of lanthanoid pyrazolates from free lanthanoid metals, pentafluorophenylsilver, and pyrazoles, aided by a facile synthesis of polyfluoroarylsilver compounds

Zhifang Guo, Jenny Luu, Victoria Blair, Glen B. Deacon, Peter C. Junk

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11 Citations (Scopus)

Abstract

The polyfluorophenylsilver complexes [Ag 2 (C 6 F 4 Br-4) 2 (py) 3 ] (py = pyridine) (1) and [{Ag 2 R 2 (py) 2 } n ] [R = C 6 F 5 (2); C 6 F 4 Br-3 (3); C 6 F 4 H-4 (4)] were prepared in reasonable yields by reactions of silver(I) oxide with the appropriate polyfluorobenzenes in pyridine. This simple and convenient synthesis is selective and does not lead to debromination of C 6 HF 4 Br-(3 or 4). Complex 1 is dinuclear with AgR 2 and Ag(py) 3 units linked by a bridging polyfluoroaryl group and Ag···Ag interactions, whereas 2–4 are polymeric with alternating AgR 2 and Ag(py) 2 units similarly linked. The trivalent lanthanoid pyrazolates, [Ln(Ph 2 pz) 3 (py) 2 ]·2thf (Ph 2 pz = 3,5-diphenylpyrazolate; Ln = Yb, 5, Er, 6, Dy, 7, Lu, 8; thf = tetrahydrofuran), [Ho(Ph 2 pz) 3 (py)(thf)] (9), [Ln(Ph 2 pz) 3 (py)(dme)]·solv (Ln = Tb, solv = 1.75PhMe, 10, Gd, solv = 1.5dme, 11; dme = 1,2-dimethoxyethane; PhMe = toluene), [Ln(Ph 2 pz) 3 (thf) 3 ] (Ln = La, 12, Ce, 13, Nd, 14), [Ln(tBu 2 pz) 3 (py) 2 ] (tBu 2 pz = 3,5-di-tert-butylpyrazolate; Ln = Yb, 15, Tm, 16, Ho, 17, Dy, 18), [Yb(Phtpz) 3 (py) 2 ]·PhMe (19) (Phtpz = 3-Phenyl-5-(2′-thienyl)pyrazolate) and [Nd(ttfpz) 3 (dme) 2 ] (20) (ttfpz = 3-(2′-thienyl)-5-(trifluoromethyl)pyrazolate) have been prepared by redox transmetallation/protolysis (RTP) reactions employing lanthanoid metals, pentafluorophenylsilver and the corresponding pyrazoles (pzH) in donor solvents. This is a new synthetic route in which AgC 6 F 5 replaces the more commonly used Hg(C 6 F 5 ) 2 or HgPh 2 . Yields are good to excellent if long crystallization times are used but the heavier Ln metals require activation with iodine to induce reaction. The monomeric structures exhibit η 2 -bound pyrazolate ligands with eight-coordinate metal atoms for complexes 5–9 and 15–19, nine-coordinate metal atoms for complexes 10–14, and ten-coordinate metal atoms for complex 20.

Original languageEnglish
Pages (from-to)1018-1029
Number of pages12
JournalEuropean Journal of Inorganic Chemistry
Volume2019
Issue number7
DOIs
Publication statusPublished - 21 Feb 2019

Keywords

  • Crystal structures
  • Lanthanoid pyrazolates
  • Protolysis (RT/RTP) reactions
  • Redox transmetallation
  • Silver polyfluorophenyls

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