| Summary: | A hemipyridine solvate of bis(pyridine)silver(I) perchlorate, [Agpy<sub>2</sub>ClO<sub>4</sub>]·0.5py (compound <b>1</b>) was prepared and characterized by single crystal X-ray analysis and vibrational spectroscopy (R and low-temperature Raman). Compound <b>1</b> was prepared via the trituration of [Agpy<sub>2</sub>ClO<sub>4</sub>] and 4[Agpy<sub>2</sub>ClO<sub>4</sub>]·[Agpy<sub>4</sub>]ClO<sub>4</sub> (as the source of the solvate pyridine) in a mixed solvent of acetone:benzene =1:1 (v = v) at room temperature. The monoclinic crystals of compound <b>1</b> were found to be isomorphic with the analogous permanganate complex (a = 19.1093(16) Å, b = 7.7016(8) Å, c = 20.6915(19) Å, β = 105.515(7)°; space group: C2/c). Two [Agpy<sub>2</sub>]<sup>+</sup> cations formed a dimeric unit [Agpy<sub>2</sub>ClO<sub>4</sub>]<sub>2</sub>, and each silver ion was connected to two ClO<sub>4</sub><sup>−</sup> anions via oxygen atoms. The Ag∙∙∙Ag distance was 3.3873(5) Å, the perchlorate ions were coordinated to silver ions, and the Ag∙∙∙O distances were 2.840(2) Å and 2.8749(16) Å in the centrosymmetric rectangle of Ag-O-Ag-O. The stoichiometric ratio of the monomer [Agpy<sub>2</sub>ClO<sub>4</sub>] and the solvent pyridine was 1:0.5. The guest pyridine occupied 527.2 Å<sup>3</sup>, which was 18.0% of the volume of the unit cell. There was no additional residual solvent-accessible void in the crystal lattice. The solvate pyridine was connected via its a-CH to one of the O atoms of the perchlorate anion. Correlation analysis, as well as IR and low-temperature Raman studies, were performed to assign all perchlorate and pyridine vibrational modes. The solvate and coordinated pyridine bands in the IR and Raman spectra were not distinguishable. A perchlorate contribution via Ag-O coordination to low-frequency Raman bands was also assigned.
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