One‐Pot Synthesis and Structure of Organochalcogen Halides with Mixed Valence States

Abstract

Treatment of the diorganodichalcogenides PhEEPh (E = Se, Te) with one equivalent of elemental halogen (bromine or iodine) in methanol followed by addition of a sulfur donor and one more equivalent of the corresponding organochalcogen trihalide PhTeX 3 affords the mixed-oxidation-state organochalcogen halides [PhE II (L)PhEЈ IV X 4 ] (E = Se, Te; EЈ = Te; X = Br, I; L = thiourea, tetramethylthiourea) in a one-pot procedure. The X-ray structural analyses of these compounds suggest a strong dependence of the formation of supramolec-

Synthesis of new T-shaped hypervalent complexes of tellurium showing Te–π-aryl interactions: X-ray characterization of [(mes)XTe(μ-X)Te(mes)(etu)] (X=Br, I) and [Ph(etu)Te(μ-I)Te(etu)Ph][PhTeI4] (mes=mesityl; etu=ethylenethiourea)

“…Complexes 2 and 3 generate each one a lone, wide peak localized in 778 (2) and 861 ppm (3). Recent experiments of 125 Te NMR with the neutral complex [(tmtu)PhTe(l-Br)TeBr 3 Ph] 2 [11] have showed similar results to those obtained for 1. The occurrence of only one large signal for compounds 2 and 3 could be attributed to their probable dissociation and to the further solvatation equilibrium of the species in solution.…”

“…Recently, we have described [11] the one-pot synthesis and the structures of the compounds PhE II (L)PhE 0IV X 4 (E = Te, Se; E 0 = Te; X = Br, I; L = thiourea, N,N 0 -tetramethylhiourea): in the two salts of the four complexes [(tmtu) PhTe(l-Br)TeBr 3 Ph] 2 , [(tu)PhTe(l-I)TeI 3 -complex) counter ions, since both cation and anion are complexes themselves, with different oxidation states of the atomic centers, +2 and +4 for the cation and the anion, respectively. We report now the synthesis of the novel compounds of tellurium(II) [(mes)BrTe(l-Br)Te(mes)(etu)] (1) and [(mes) ITe(l-I)Te(mes)(etu)] (2), also the mixed valence complex [Ph(etu)Te(l-I)Te(etu)Ph][PhTeI 4 ] (3) {mes = mesityl(2,4, 6-trimethylphenyl); etu = ethylenethiourea(2-imidazolidinethione); Ph = phenyl}. Such molecular assemblies (in the case of 1 and 2) are yet unknown and the T-shaped [12,13] X-Te-X bonds are quite equal and linear.…”

Synthesis and characterization of the first aryltellurium(II) halide complex stabilized by a Te–Te bond from a tellurium ether

“…The reaction between [b-naphtyl-Te] 2 and an equivalent amount of iodine affords [(b-naphtyl) 2 TeI 2 ] and elemental tellurium [2]. When the same reaction is carried out using [(2,4,6-Ph 3 C 6 H 2 )Te] 2 , the compound (2,4,6-Ph 3 C 6 H 2 )TeI 3 [3] is formed as a result of a disproportion reaction in inert atmosphere or an oxo-bridged tellurium(IV) compound in the presence of air [4].…”

“…Based on previous results [1][2][3]7], we suggest that MesTeI disproportionates to (I), MesTeI 3 and elemental tellurium according to the following equation: …”

Uncommon assembling of organotellurium iodides: Synthesis and X-ray characterization of [mesTeI(μ-I)2(TeImes)2]n, (C5H6N)4[mesTeI2]2(I3)2 and {(C5H6N)3[(mesTeI3)(μ-I−)(TeI3mes)](I3)2}n (mes=2,4,6-trimethylphenyl)

“…Recently we have described the preparation of the new T-shaped organotellurium(II) dihalides (PyH)[mesTeI 2 ], (PyH) [mesTeIBr] and (PyH)[mesTeICl] (Py = pyridine), starting from (mesTe) 2 and inserting two different halogen atoms on tellurium [1]. The anions [mesTeI 2 ] À and [mesTeIBr] À are assembled as dimers by reciprocal, secondary TeÁ Á ÁX interactions, linked also to the pyridinium cations through l-NHÁ Á ÁX bonding; the anion [mesTeICl] À do not interact with neighboring anionic moieties, but attains also secondary NHÁ Á ÁCl bonding.…”