EPR‐spektroskopische Charakterisierung (X‐, Q‐Band) monomerer AgII‐ und AuII‐Komplexe der Thiakronenether [12]anS4, [16]anS4, [18]anS6 und [27]anS9

EPR Spectroscopic Characterization (X‐, Q‐Band) of Monomeric Ag^II‐ and Au^II‐Complexes of the Thiacrownethers 12]aneS₄, 16]aneS₄, 18]aneS₆ and 27]aneS₉ The reaction of the prepared Ag^I complexes of the thiacrownethers 12]aneS₄, 16]aneS₄, 18]aneS₆ and 27]aneS₉ with c. H₂SO₄ as well as the reaction of Au^IIICl₄]^‐ with 18]aneS₆ and 27]aneS₉ leads to labile Ag^II‐ (4d⁹, ^{107, 109}Ag: I=1/2) and Au^II‐ (5d⁹, ¹⁹⁷Au: I=3/2) thiacrownether complexes, respectively, which were characterized by X‐ and Q‐band EPR. The EPR spectra of Ag^II(12]anS₄)]²⁺ and Ag^II(18]anS₆)]²⁺ were reinvestigated. According to an analysis of the spin‐density distribution only 20 ‐ 25 % is located on the Ag or Au atoms. Most of the spin‐density was found to be on the S donor atoms of the thiacrownethers. The high delocalization of the spin‐density leads certainly to a noticeable reduction of the Ag^I/Ag^II redox potential and is considered as being mainly responsible for the easy accessibility of the Ag^II compounds.