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
1
K(Sn−Cht)RC,
1
K(Sn−Chmb)RC, and
1
K(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
+)3Sn2Se6
4-
(1),
(enH+)2(2,2,2-crypt-K+)2Sn2Se6
4-
(2), and (K+)2(2,2,2-crypt-K+)2Sn2Te6
4-
(3) were shown to correlate with the
1
K(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+)2HOSnTe3
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.
