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Abstract

Monoanionic ligands of the type [R 2 P(E)NP(E)R 2 ] À 1 have been investigated extensively as ligands for both main group elements [1] and transition metals. [2] This widespread interest stems from their potential uses as lanthanide shift reagents, [2] industrial catalysts, [3] luminescent materials, [4] or in metal extraction processes. [5] Recently we [6] and Stahl et al. [7] reported the first ambidentate dianionic ligands [RN(E)P(m-NR) 2 P(E)NR] 2À 2, which adopt a variety of bonding modes, that is N,E, N,N', or E,E', with metal centers.Despite this intense activity, the tellurium analogues of 1 and 2 are unknown. Anionic tellurophosphinic amides of the type [tBu 2 P(Te)NR] À (R ¼ iPr, Cy) can be prepared by lithiation of [tBu 2 P(Te)NHR] with LinBu, and chelate complexes of this anion with Group 12 metals have been investigated as single-source precursors of binary metal tellurides. [8] Although ditellurides of the type [R(Te)P(m-NtBu) 2 P(Te)R] (R ¼ Me, tBu) have been reported, [9] our attempts to oxidize tBuN(H)P(m-NtBu) 2 PN(H)tBu with an excess of elemental tellurium in boiling toluene produced only the monotelluride [tBuNH(Te)P(m-NtBu) 2 PN(H)tBu] in about 5 % yield. [10] Endeavors to generate (TePPh 2 ) 2 NH in a similar manner have also been unsuccessful. Consequently, we adopted a different approach to the synthesis of the anionic ligands 1 (E ¼ Te) and 2 (E ¼ Te), which involves metalation of the neutral imido or amido precursor prior to the reaction with tellurium. [11] Herein, we report the synthesis and X-ray structures of [{[Na(tmeda)][(TePPh 2 ) 2 N]} 2 ] (3) and [Li(tmeda)] 2 [Te(NtBu)P(m-NtBu) 2 P(NtBu)Te] (4), (tmeda ¼ tetramethylethylenediamine), which contain the first examples of 1 (E ¼ Te) and 2 (E ¼ Te), respectively.

The cyclic [N(PiPr2E)2]+ (E = Se, Te) cations: a new class of inorganic ring system

“…8,9 A fascinating feature of the chemistry of 1c is the 40 formation of the unusual ditelluride 2c upon stoichiometric oxidation of the sodium salt with iodine. 8,9 The ditelluride 2c may be considered to be the dimer of the tellurium-centered radical [TeP i Pr2N i Pr2PTe]…”

A Silver(I) Iodide Complex of a Tellurophosphorane

“…[Li(TMEDA)] 2 [tBuN(Te)P(-NtBu) 2 P(Te)NtBu)] was synthesized according to the literature procedure. [7] Spectroscopic methods NMR spectra were recorded using a JEOL DELTA EX 270 or a BRUKER Avance II 400 spectrometer. TMS was used as an internal standard for 1 H NMR.…”

“…[4] We have previously shown that the phosphorus-tellurium bond is stabilized by a negative charge in the anionic ligands {[R 2 P(Te)] 2 N} − [5] and we reported the X-ray structures of hexameric and tetrameric Ag(I) complexes of this ligand for R = iPr and Ph, respectively. [6] In a sequel to that work we have now investigated the reaction of the P-Te dianion [tBuN(Te)P(-NtBu) 2 P(Te)NtBu)] 2− (A) [7] with silver(I) iodide and found, unexpectedly, that a AgI complex of the neutral monotelluride ([tBu(H)N(Te)P(-NtBu) 2 PN(H)tBu]) (B) [8] is formed.…”

“…[7] A similar elongation compared to the free ligand was observed for the P-Te distances in the Ag + complexes of iPr 3 PTe reported by du Mont et al [3] The 31 P NMR spectrum of (2) at 25 °C exhibits two broad resonances at 83.0 and −46.0 ppm [ 1 J(P,Te) = 1939 Hz] attributed to the P(III) and P(V) centers, respectively, (cf. 1 J(P,Te) = 2024 Hz for B).…”

A New Approach to Metalated Imido and Amido Tellurophosphoranes

“…[8] Although ditellurides of the type [R(Te)P(m-NtBu) 2 P(Te)R] (R ¼ Me, tBu) have been reported, [9] our attempts to oxidize tBuN(H)P(m-NtBu) 2 PN(H)tBu with an excess of elemental tellurium in boiling toluene produced only the monotelluride [tBuNH(Te)P(m-NtBu) 2 PN(H)tBu] in about 5 % yield. [10] Endeavors to generate (TePPh 2 ) 2 NH in a similar manner have also been unsuccessful. Consequently, we adopted a different approach to the synthesis of the anionic ligands 1 (E ¼ Te) and 2 (E ¼ Te), which involves metalation of the neutral imido or amido precursor prior to the reaction with tellurium.…”