Competitive Te-Te and C-Te bond cleavage in the oxidative addition of diaryl and dialkyl ditellurides to Pt(0) centers

Abstract

† Electronic Supplementary Information (ESI) available: Crystal data and details of structure determination and selected bond parameters of 2-5, CCDC 1522462-1522465, Definition of the angle of distortion. Energy profile of Th2Te2 + [Pt((h 2nb)(dppn)]. 31 P{ 1 H} NMR spectrum of [Pt(TeTh)2(dppn)].The oxidative addition reaction of ditellurides R2Te2 [R = n Bu, Ph, Th (2-thienyl, C4H3S)] to [Pt(η 2 -nb)(dppn)] (nb = norbornene, dppn = 1,2-bis(diphenylphosphino)naphthalene) was found to afford [Pt(TeR)2(dppn)] [R = n Bu (1), Ph (2), Th (3)] and [Pt(TeR)(R)(dppn)] [R = Ph (4), Th (5)] as a result of the cleavage of the Te-Te or C-Te bond, respectively. The reactions and the product distributions were monitored by 31 P{ 1 H} NMR spectroscopy. The spectral interpretation was assisted by the high-yield preparation of [Pt(TePh)2(dppn)] (2) and [Pt(TeTh)2(dppn)] (3) by ligand echange reactions from [PtCl2(dppn)], and by the crystal structure determinations and spectral characterizations of 2 and 3. Two series of reactions were carried out both at room temperature and at -80 o C. One involved the addition of the toluene solution of R2Te2 to that of [Pt(η 2 -nb)(dppn)], and the other the addition of [Pt(η 2 -nb)(dppn)] solution to the R2Te2 solution. The oxidative addition of n Bu2Te2 to [Pt(η 2 -nb)(dppn)] yielded solely [Pt(Te n Bu)2(dppn)]. In case of Ph2Te2 and Th2Te2, the reaction of equimolar amounts of ditelluride and [Pt(η 2 -nb)(dppn)] afforded only [Pt(TeR)(R)(dppn)] (R = Ph, Th), but when an excess of R2Te2 was used, the addition of [Pt(η 2 -nb)(dppn)] to the ditelluride resulted in the formation of a mixture of [Pt(TeR)2(dppn)] and [Pt(TeR)(R)(dppn)] with the latter the main component. An excess of R2Te2 and the lowering of the temperature favoured the formation of [Pt(TeR)2(dppn)]. The reaction energetics in toluene was calculated at revPBE GGA DFT / TZVP(f) level of theory. The increase of the electron withdrawing nature of the organic substituent rendered [Pt(TeR)(R)(dppn)] increasingly stable with respect to [Pt(TeR)2(dppn)]. The computation of the energy profiles of the likely pathways of the oxidative addition indicated that concurrent formation of [Pt(TeR)2(dppn)] and [Pt(TeR)(R)(dppn)] (R = Ph, Th) may be more likely than the formation of the latter due to the decomposition of the former. This was verified experimentally by stirring pure [Pt(TeR)2(dppn)] in toluene for a prolonged time at room tempertature. No decomposition was observed.

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.…”

Dependence of Transition-Metal Telluride Phases on Metal Precursor Reactivity and Mechanistic Implications

“…It is possible that the proposed one-electron decomposition routes of the didodecyl ditelluride reagent on the metal cations facilitate this type of bonding by selectively breaking the C–Te bonds of the ditellurides. While intermediates from oxidation addition of ditellurides on M(0) complexes have been captured and identified, − we are unaware of any captured intermediates of reactions of ditellurides on M­(II) and M­(III) complexes.…”

Organodiphosphines in PtP2X2 (X = As, Ge or Te) derivatives – Structural aspects

“…In two monoclinic [Pt{η 2 -Ph 2 P(CH 2 ) 2 PPh 2 }(TePh) 2 ] (at 120 K) and [Pt{η 2 -Ph 2 P(CH 2 ) 2 PPh 2 }{Te(C 4 H 3 S)} 2 ] (at 120 K) (Risto et al, 2007) each Ph 2 P(CH 2 ) 2 PPh 2 forms a five-membered metallocyclic ring with the mean value of 86.6° (PC 2 P). In another three complexes: orthorhombic [Pt {η 2 -Ph 2 P(CH 2 ) 3 PPh 2 }{Te(mes)} 2 ]‧3C 6 H 6 (at 100 K) (Chauhan et al, 2013), monoclinic [Pt{η 2 -Ph 2 P(C 10 H 6 )PPh 2 }{Te(Ph)} 2 ]‧ 3toluene (at 133 K), and triclinic [Pt{η 2 -Ph 2 P(C 10 H 6 ) PPh 2 }{Te(C 4 H 3 S)} 2 ] (at 133 K) (Karjalainen et al, 2017) each of the bidentate-P,P-donor ligand creates sixmembered metallocyclic ring with the mean value of P-Pt-P bite angle of 91.2° (PC 3 P). Structure of [Pt {η 2 -Ph 2 P(C 10 H 6 )PPh 2 }{Te(C 4 H 3 S)} 2 ] (Karjalainen et al, 2017) is shown in Figure 3 as an example.…”