Platinum-Mediated Activation of Coordinated Organonitriles by Telluroethers in Tetrahydrofuran: Isolation, Structural Characterization, and Density Functional Theory Analysis of Intermediate Complexes

Abstract

The reactions of [PtCl2(NCR)2] with telluroethers (ArAr'Te) in organic solvents have been investigated. The reactions in dichloromethane yield [PtCl2(TeArAr')2], while those in tetrahydrofuran (THF) give different products depending on the steric demands of the aryl groups on tellurium, the molarity of the reactants, and the reaction conditions. The reactions between [PtCl2(PhCN)2] and TeArAr' in 1:1 molar ratio at room temperature in THF yield several products, like [PtCl2(TeArAr')2] (Ar/Ar' = Ph/Ph, o-tol/Mes, Mes/Mes), [PtCl2(PhCN){NC(O)Ph[TeMes(o-tol)]}], and [PtCl2{NC(O)Ph(TeMes2)}2]. The reaction with TeMes2 in refluxing THF gave [PtCl2{NC(Ph)C4H7O}{NC(O)Ph(TeMes2)}] and [PtCl(TeMes2){Te(Mes)CH2C6H2Me2}], depending on the duration of heating. Reaction of [PtCl2(PhCN)2] with TeArMes afforded [PtCl2(TeArMes)2] (Ar = Ph, o-tol, and Mes), the formation of which decreased with increasing steric demand of the Ar group, together with [PtCl2{NC(O)Ph(TeArMes)}2]. The telluroether in the latter binds to nitrogen, and tellurium exists in the formal oxidation state of +4 (from XPS). The tellurium in these complexes exhibits secondary interactions with platinum (J((195)Pt-(125)Te) = 309-347 Hz) and with the carbonyl oxygen. These complexes slowly dissociate in solution to give [PtCl2(TeMesAr){NC(O)Ph(TeMesAr)}], finally leading to the formation of [PtCl2(TeMesAr)2]. Molecular structures of trans-[PtCl2(PhCN){NC(O)Ph[TeMes(o-tol)]}], trans-[PtCl2{NC(O)Ph(TeMes2)}2], trans-[PtCl2{NC(Ph)C4H7O}{NC(O)Ph(TeMes2)}], trans-[PtCl2{NC(O)Ph[TeMes(o-tol)]}2], trans-[PtCl2(TeMes2){NC(O)Ph(TeMes2)}], trans-[PtCl2{NC(O)Me(TeMes2)}2], and [PtCl(Te-o-tol){NC(O)Ph}2] have been unambiguously established by single-crystal X-ray diffraction analyses. Density functional theory calculations for some of the complexes were performed, and geometrical parameters are in good agreement with the values obtained from X-ray analyses.

Reactions of Schiff Base‐Substituted Diselenides and ‐tellurides with Ni(II), Pd(II) and Pt(II) Phosphine Complexes

“…For most of the structural parameters, a linear dependence with the size of the chalcogen or the size of the metal is observed along the series [M(L S )(PPh 3 )] – [M(L Se )(PPh 3 )] – [M(L Te )(PPh 3 )]. The Pd1–Te1 and Pt1–Te1 bonds of 2.4825(2) and 2.502(1) Å are similar to the shortest bond lengths reported in previous studies of palladium [ 21,25–29,34,36–38 ] and platinum [ 39–52 ] phenyltellurolato complexes. Remarkably and probably as a result of the strain in the five‐membered Te1–Ni1–N1 chelate ring, the Ni1–Te1 bond length in [Ni(L Te )(PPh 3 )] is only 2.4050(5) Å.…”

“…Selected bond lengths [Å] and angles (°) in the dichalcogenides {HL Y } 2 [30] and their nickel, palladium and platinum complexes [M(L Y )(PPh 3 )] (Y = Se, Te). [21,[25][26][27][28][29]34,[36][37][38] and platinum [39][40][41][42][43][44][45][46][47][48][49][50][51][52] [53] Ni(TeMes)Cp(PEt 3 ), [54] [W(CO) 5 -μ-(TePh)NiCp(PPh 3 )] [55] and [57] [(NiCpiPr 4 ) 2 -μ-( Te) 2 ] (2.44-2.45 Å), [58] [CpFe(C 5 H 4 )-Te(I) 2 -Ni(NHC)Cp] (2.4407(8) Å) [59] and (μ 4 -telluro)-hexakis(μ 3 -telluro)bis(μ 2 -bis(diphenylphosphino)methane)-bis(η 5 -tert-butylcyclopentadienyl)-pentanickeldiniobium (2.436(5) Å) [60] show the overall shortest Ni-Te bond lengths. (m/z = 538.0818) can be observed.…”

Ph2Te2: An Accessible Main Group Organometallic Target for Spectral Characterization and Modeling

“…Ditellurides are commonly prepared ,,,− by the direct combination of elemental tellurium with organomagnesium or organolithium reagents. Tellurium inserts between the C–M (M = Li or Mg) bond effectively generating an organotelluride anion (Figure ).…”

“…Numerous routes for the synthesis of diphenyl ditelluride have been reported in the literature. − The pathway ,− utilized in this lab exercise was chosen for (1) its mechanistic straightforwardness for students that have recently completed organic chemistry, (2) the familiarity of the Grignard reagent to these same students, and (3) the general availability or easy preparation of the organomagnesium precursor for most undergraduate institutions.…”

Emerging trends in organotellurolate chemistry derived from platinoids

“…In the case of the latter ligand system, palladium is directly coordinated to all four nitrogen atoms. 92,93 An interesting example of a halobridged complex, [ [93][94][95] These complexes were formed due to the chlorobridged cleavage reaction with the substitution of thio and seleoether through monotellurides. Usually, telluroether complexes are oriented in the cis form, which is slowly transformed to the trans isomer in solution.…”