DITIN(IV) CHALCOGENIDE ANIONS - SE-77, SN-119, AND TE-125 SOLUTION NMR STUDY OF THE SN(2)CH(6)(4-) AND SN(2)CH(7)(4-) (CH=SE, TE) ANIONS, X-RAY CRYSTAL STRUCTURES AND RAMAN SPECTRA OF K+(N(CH3)(4)(+))(3)SN2SE64-, (ENH(+))(2)(2,2,2-CRYPT-K+)(2)SN2SE64

摘要

The seleno- and tellurostannate(IV) anions Sn(2)Ch(6)(4-) and Sn(2)Ch(7)(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 Se-77, Sn-119, and Te-125 NMR spectroscopy. The magnitudes of the relativistically corrected reduced coupling constants K-1(Sn-Ch(t))(RC), K-1(Sn-Ch(mb))(RC), and K-1(Sn-Ch(db))(RC) were shown to be consistent with a significant degree of s-character in the bonding. The Sn-Ch(mb) and Sn-Ch(t) bond distances observed for the dimeric SnCh(3)(2-) anions, namely Sn(2)Ch(6)(4-), in K+(N(CH3)(4)(+))(3)Sn2Se64- (1), (enH(+))(2)(2,2,2-crypt-K+)(2)Sn2Se64- (2), and (K+)(2)(2,2,2- crypt-K+)(2)Sn2Te64- (3) were shown to correlate with the K-1(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 HOSnTe33- anion, the hydroxide derivative of the SnTe32- anion, has been structurally characterized by X-ray crystallography in K+(2,2,2-crypt-K+)(2)HOSnTe33- (4) and in K+(2,2,2-crypt-K+)(2)HOSnTe33-. en (5) and represents the first example of a simple mixed hydroxychalcogenide anion of tin. [References: 89]