Ditin(IV) Chalcogenide Anions: Se-77, Sn-119 and Te-125 Solution NMR Study of Seleno- and Tellurostannate(IV) Anions (see abstract), and X-Ray Crystal Structures and Raman Spectra of the Stannates (1), (2) and (3), and X-Ray Crystal Structures of (4) and (5)

The seleno- and tellurostannate(IV) anions Sn2Ch6^4- and Sn2Ch7^4- (Ch = Se, Te) have been obtained by extraction of the ternary alloys KSn0.67Se1.93 and KSn0.63Te1.70 in ethylenediamine (en) and/or liquid NH3 in the absence and in the presence of nonstoichiometric amounts of 2,2,2-crypt (4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]-hexacosane) with respect to K⁺. The anions were characterized in solution for the first time by natural abundance ⁷⁷Se, ¹¹⁹Sn, and ¹²⁵Te NMR spectroscopy. The magnitudes of the relativistically corrected reduced coupling constants ¹K(Sn-Cht)RC, ¹K(Sn-Chmb)RC, and ¹K(Sn-Chdb)RC were shown to be consistent with a significant degree of s-character in the bonding. The Sn-Chmb and Sn-Cht bond distances observed for the dimeric SnCh3^2- anions, namely Sn2Ch6^4-, in K+(N(CH3)4⁺)3Sn2Se 6^4- (1), (enH⁺)2(2,2,2-crypt-K⁺)2Sn 2Se6^4- (2), and (K⁺)2(2,2,2-crypt-K⁺)2Sn 2Te6^4- (3) were shown to correlate with the ¹K(Sn-Ch)RC values, indicating that the solid-state molecular structures of the anions are retained in solution. The Raman spectra of compounds 1-3 are also reported along with their respective factor-group analyses. The novel HOSnTe3^3- anion. the hydroxide derivative of the SnTe3^2- anion, has been structurally characterized by X-ray crystallography in K⁺(2,2,2-crypt-K⁺)2-HOSnTe3^3- (4) and in K⁺(2,2,2-crypt-K⁺)2HOSnTe3 ^3-·en (5) and represents the first example of a simple mixed hydroxychalcogenide anion of tin.