Syntheses, Vibrational Spectra, and Theoretical Studies of the Adamantanoid Sn₄Ch₁₀^4- (Ch = Se, Te) Anions:  X-ray Crystal Structures of [18-Crown-6-K]₄[Sn₄Se₁₀]·5en and [18-Crown-6-K]₄[Sn₄Te₁₀]·3en·2THF

Abstract

The salts [18-crown-6-K](4)[Sn(4)Se(10)].5en and [18-crown-6-K](4)[Sn(4)Te(10)].3en.2THF were isolated upon addition of THF to the ethylenediamine (en) extracts of the alloys KSn(0.90)Se(1.93) and K(4)Sn(4)Te(10) that had been extracted in the presence of 18-crown-6 (1,4,7,10,13,16-hexaoxacyclooctadecane). The Sn(4)Te(10)(4-) anion has been structurally characterized for the first time by a single-crystal X-ray diffraction study of [18-crown-6-K](4)[Sn(4)Te(10)].3en.2THF: P2(1)/n, a = 22.420(5) A, b = 19.570(4) A, c = 24.680(5) A, beta = 96.90(3)(o), Z = 4, and R(1) = 0.0468 at -183 degrees C. In addition to Si(4)Te(10)(4-) and Ge(4)Te(10)(4-), the Sn(4)Te(10)(4-) anion represents the only other known group 14 adamantanoid telluride. The X-ray crystal structure determination of the related [18-crown-6-K](4)[Sn(4)Se(10)].5en salt has also been determined: P2(1)/n, a = 22.003(2) A, b = 18.966(2) A, c = 24.393(2) A, beta = 97.548(8)(o), Z = 4, and R(1) = 0.0843 at -123 degrees C. The anion geometries are of the adamantanoid type where the Sn(IV) atoms occupy the bridgehead positions and the chalcogen atoms occupy the bridging and terminal sites. The energy minimized geometries of Sn(4)Ch(10)(4-) have also been determined using density functional theory (DFT). Mayer bond order analyses, Mayer valencies, and empirical bond valencies indicate that the terminal Sn-Ch bonds have significant multiple bond character, with the terminal Sn-Se bond having more multiple bond character than the terminal Sn-Te bond. The vibrational frequencies of the Sn(4)Se(10)(4-) and Sn(4)Te(10)(4-) anions have been calculated using DFT methods, allowing the Raman spectrum of Sn(4)Se(10)(4-) to be fully assigned.

Synthesis of Periodic Hexagonal Surfactant Templated Platinum Tin Tellurides: Narrow Band Gap Inorganic/Organic Composites

“…The lower tin-to-tellurium ratio of 2.73 suggests the formation of new tin telluride clusters. While the ratio does not match any one tin telluride oligomer exactly, it suggests the material has a majority if its tin telluride is either Sn 2 Te 6 4- or Sn 4 Te 10 4- . ,, The Sn 2 Te 6 4- cluster can be formed by a relatively straightforward dimerization of the starting cluster, so this species should be the kinetically favored building block. The condensation of SnTe 4 4- clusters into large species is generally thought to be controlled by either cation-mediated ion pairing or halogen-catalyzed tellurium elimination. , Both of these routes would be available in the platinum tin telluride system.…”

DFT Calculations of the Electric Field Gradient at the Tin Nucleus as a Support of Structural Interpretation by 119Sn Mössbauer Spectroscopy

“…[43,44] Concerning the importance of relativistic effects for the tin atom, we outline that all-electron relativistic calculations, even at scalar level, are extremely costly. [43] Moreover, the use of relativistic effective core potential basis sets [43] in our calculations was ruled out by the importance, in our study, of the core electrons, as we have verified in preliminary investigations.…”

Synthesis and Crystal Structure of [Li8(H2O)29]­[Sn10O4S20]·2H2O

“…This way, Li + salts of monomeric, dimeric, or polymeric anions [Sn E 4 ] 4– , [Sn 2 E 6 ] 4– or {[Sn E 3 ] 2– } n ( E = S, Se) were isolated and characterized as solvates or without crystal solvent 9. However, in spite of the high stability of the adamantane‐like, tetrameric anion [Sn 4 E 10 ] 4– , that is known in a variety of phases A 4 [Sn 4 E 10 ] ( A = NMe 4 , NEt 4 , 18‐Crown‐6‐K; E = S, Se, Te),13,14 it was not possible so far to isolate Li 4 [Sn 4 E 10 ] or any of its solvates upon following this route. Hence we intended to apply another synthetic approach under less drastic conditions, according to the known condensation equilibrium of binary 14/16 anions in protic solution (Scheme ) that is dependent on the pH value 15…”