Mesityltellurenyl Cations Stabilized by Triphenylpnictogens [MesTe(EPh₃)]⁺ (E = P, As, Sb)

Abstract

The homoleptic 1:1 Lewis pair (LP) complex [MesTe(TeMes2)]O3SCF3 (1) featuring the cation [MesTe(TeMes2)](+) (1a) was obtained by the reaction of Mes2Te with HO3SCF3. The reaction of 1 with Ph3E (E = P, As, Sb, Bi) proceeded with substitution of Mes2Te and provided the heteroleptic 1:1 LP complexes [MesTe(EPh3)]O3SCF3 (2, E = P; 3, E = As) and [MesTe(SbPh3)][Ph2Sb(O3SCF3)2] (4) featuring the cations [MesTe(EPh3)](+) (2a, E = P; 3a, E = As; 4a, E = Sb) and the anion [Ph2Sb(O3SCF3)2](-) (4b). In the reaction with Ph3Bi, the crude product contained the cation [MesTe(BiPh3)](+) (5a) and the anion [Ph2Bi(O3SCF3)2](-) (5b); however, the heteroleptic 1:1 LP complex [MesTe(BiPh3)][Ph2Bi(O3SCF3)2] (5) could not be isolated because of its limited stability. Instead, fractional crystallization furnished a large amount of Ph2BiO3SCF3 (6), which was also obtained by the reaction of Ph3Bi with HO3SCF3. The formation of the anions 4b and 5b involves a phenyl group migration from Ph3E (E = Sb, Bi) to the MesTe(+) cation and afforded MesTePh as the byproduct, which was identified in the mother liquor. The heteroleptic 1:1 LP complexes 2-4 were also obtained by the one-pot reaction of Mes2Te, Ph3E (E = P, As, Sb) and HO3SCF3. Compounds 1-4 and 6 were investigated by single-crystal X-ray diffraction. The molecular structures of 1a-4a were used for density functional theory calculations at the B3PW91/TZ level of theory and studied using natural bond order (NBO) analyses as well as real-space bonding descriptors derived from an atoms-in-molecules (AIM) analysis of the theoretically obtained electron density. Additionally, the electron localizability indicator (ELI-D) and the delocalization index are derived from the corresponding pair density.

Studies of Multicenter and Intermolecular Dihydrogen B–H···H–C Bonding in [4,8,8′‐exo‐{PPh3Cu}‐4,8,8′‐(μ‐H)3‐commo‐3,3′‐Co(1,2‐C2B9H9)(1′,2′‐C2B9H10)]

“…These characteristics are typical for localized polar-covalent interactions, although the ELI pop value is unusually large for disynaptic basins; for example, for the Te···PPh 3 bond in [MesTe(PPh 3 )] + (ref. [52] ) the ELI pop is equal to only 1.89 e. As mentioned in ref.…”

“…The theoretical charges of the phosphorus atom and phenyl moieties are similar to those in [MesTe(PPh 3 )] + . [52] Interestingly, the overall charges for {nido-C 2 B 9 H 11 } dianions are similar in the case of the isolated molecule (-0.64 and -0.65 e) but different in the crystal (-0.62 and -0.95 e); this might be caused by a different crystalline environment or be an effect of the PPh 3 Cu···Cobdc bonding. Besides covalent and coordination bonds, there exists intramolecular B-H···H-C hydrogen bonding in 1 (Figure 1, b) with r(B9Ј···C20) = 4.1044(1) Å.…”

Molecular Structure and Real‐Space Bonding Descriptors (AIM, ELI‐D) of Phenyl(triphenylstannyl)telluride

“…[3,4] We prepared Ph 3 SnTePh by salt metathesis of Ph 3 SnCl with NaTePh (generated in situ from PhTeTePh and Na) in liquid ammonia in 78 % yield [Equation (1)]. The melting point (97°C, lit.…”

“…+ (E = P, As, Sb) and [MesTe(TeMes 2 )] + , which are best described as mesityltelluro-substituted triphenylphosponium, triphenylarsonium, triphenylstibonium, and dimesityl telluronium cations, respectively, due to the fact that most of the positive charge is situated at the donor atoms E. [1] Aryl(triphenylstannyl)tellurides Ph 3 SnTeR are isoelectronic to aryltelluro-substituted triphenylstibonium cations [RTeSbPh 3 ] + , but lack a positive charge.…”

“…The AIMapproach has found wide applications in the last two decades, [7] however, the ELI-D introduced in 2004 is not yet a standard tool in the field. Besides our own work [1] we are aware of only one other study applying the ELI-D on tellurium compounds. [8] …”