Multinuclear magnetic resonance study of the dilead trichalcogenide anions Pb2SnCh3-n2- (Ch = Se or Te), Pb2SSeTe2-, and M2Se32- (M = Sn and/or Pb) and the crystal structures of (2,2,2-crypt-K+)2Sn2Te32- and (2,2,2-crypt-K+)2Sn2Se32-

Abstract

Se or Te), Pb2SSeTe2-, and M2Se32' (M = Sn and/or Pb) and the Crystal Structures of (2,2,2-crypt-K+)2Sn2Te32" and (2,2,2-crypt-K+)2Sn2Se32_

Trigonal Bipyramidal M2Ch32- (M = Sn, Pb; Ch = S, Se, Te) and TlMTe33- Anions: Multinuclear Magnetic Resonance, Raman Spectroscopic, and Theoretical Studies, and the X-ray Crystal Structures of (2,2,2-crypt-K+)3TlPbTe33-·2en and (2,2,2-crypt-K+)2Pb2Ch32-·0.5en (Ch = S, Se)

“…The title compounds contain trigonal bipyramidal anions of approximate D 3 h (Pb 2 Ch 3 2- ) and C 3 v (TlPbTe 3 3- ) point symmetries (Figure ) which are isostructural with the previously characterized M 2 Ch 3 2- (M = Sn, Pb; Ch = Se, Te) anions. The anions in the title compounds, as well in the previously characterized structures, − possess short apical metal−metal distances, which are a general feature among structures containing trigonal bipyramidal X 2 Y 3 units [( t -Bu) 2 Si 2 P 3 (C 6 H 11 ) 3 , Si−Si = 2.518(3) Å; ((Me 3 Si) 3 C) 2 M 2 Se 3 , M−M = 2.515 (Si), 2.672 (Ge) Å; Pn 2 (W(CO) 5 ) 3 , Pn−Pn = 2.279(4) (As), 2.663(3) (Sb), 2.818(3) (Bi) Å] and XX‘Y 3 units [SnMO 3 ( t -Bu) 3 , Sn−M = 3.200(3) (In), 3.306(3) (Tl) Å; (CO) 5 MoSnTlO 3 ( t -Bu) 3 , Sn−Tl = 3.298(1) Å; ((CO) 5 Mo) 2 SnInO 3 ( t -Bu) 3 , Sn−In = 3.078(1) Å]. The apical Pb−Pb distance in Pb 2 S 3 2- [3.1467(7) Å] is shorter than those observed in Pb 2 Se 3 2- [3.2260(8) Å] and Pb 2 Te 3 2- [3.249(2) and 3.232(1) Å].…”

“…The trigonal bipyramidal M 2 Ch 3 2- (M = Sn, Pb; Ch = S, Se, and/or Te) and SnPbSe 3 2- anions were previously synthesized and characterized by solution multi-NMR spectroscopy , and X-ray crystallography. − The structures of the M 2 Ch 3 2- (Ch = Se, Te) anions were determined by X-ray crystallography in the (2,2,2-crypt-K + ) 2 M 2 Ch 3 2- salts and were shown to possess trigonal bipyramidal geometries in which three equatorial chalcogen atoms are bonded to the two axial group 14 metals and are compressed along the M−M axis. The small Ch−M−Ch (∼90°) and M−Ch−M (∼70°) bond angles and the small magnitudes of the relativistically corrected reduced coupling constants, ( K M - Ch ) RC , suggested substantial valence p orbital involvement in the cage bonding and inert valence 5s 2 and 6s 2 electron lone pairs on M, consistent with a molecular bonding framework comprised of three valence p orbitals on M lying along the three M−Ch bonds and two valence p orbitals on each chalcogen atom, one lying along the M−Ch bond and the other, a nonbonding orbital, lying in the equatorial plane. , The ( K M - M ) RC couplings observed for the Sn 2 Se 3 2- and SnPbSe 3 2- anions were significantly larger than the ( K M - Ch ) RC couplings, and the M−M distances observed in the X-ray crystal structures were significantly shorter than the sum of the van der Waals radii of M but significantly longer than the sum of the univalent radii of M. The large couplings were rationalized on the basis of multiple coupling pathways and through-space interactions of the valence s electrons on M, and the short M−M distances, on the basis of geometric constraints imposed by metal−chalcogen bonding.…”

Synthesis and Structural Characterization of (n-Bu4N)3AuSn2Te6

“…In the known binary tin telluride compounds, there exist four types of molecular structures. These include the tetrahedral [SnTe 4 ] 4- anion and three dimeric anions, [Sn 2 Te 3 ] 2- , [Sn 2 Te 6 ] 4- , and [Sn 2 Te 7 ] 4- . While Zintl anions of the [As x Te y ] n - type act as ligands toward the synthesis of new materials, the successful incorporation of the fundamental [SnTe 4 ] tetrahedron as a building block in many telluride compounds also suggest the applicability of using ligands of the [Sn x Te y ] n - type in the construction of new structures. − The investigation of the quaternary Au−Sn−Sb−Te system has led to the isolation of the new ternary telluride compound, ( n -Bu 4 N) 4 AuSn 2 Te 6 , which indeed uses a known dimeric [Sn 2 Te 6 ] 4- anion as a ligand to bind the Au atom.…”

Neutral and cationic main group element cages of germanium(ii) with pyrazolyl ligands: solid state structures, DFT calculations and advanced solution NMR investigations

“…5 Small dianionic dilead-and ditin-trichalcogenides (III) were extracted from the corresponding alloys in the presence of stoichiometric amounts of [2,2,2]-crypt. 6 Only recently, Wright and co-workers were able to isolate a Sn II phosphinidine, [Sn 2 (m 2 -PMes) 3 ] 2-(IV), consisting of a trigonal bipyramidal Sn 2 P 3 core. 7 Cationic group 14 element-nitrogen cages of the general formula [E(m 2-3,5-Me 2 pz) 3 E] + [ECl 3 ] -(V, E = Ge, Sn) were isolated and characterised by Stalke and Steiner.…”