Selective Oxidation and Functionalization of 6-Diphenylphosphinoacenaphthyl-5-tellurenyl Species 6-Ph2P-Ace-5-TeX (X = Mes, Cl, O3SCF3). Various Types of P–E···Te(II,IV) Bonding Situations (E = O, S, Se)

Synthesis, Structure, Reactivity, and Intramolecular Donor-Acceptor Interactions in a Phosphinoferrocene Stibine and Its Corresponding Phosphine Chalcogenides and Stiboranes

Ferrocene-based phosphines equipped with additional functional groups are versatile ligands for coordination chemistry and catalysis. This contribution describes a new compound of this type, combining phosphine and stibine groups at the ferrocene backbone, viz. 1-(diphenylphosphino)-1'-(diphenylstibino)ferrocene (1). Phosphinostibine 1 and the corresponding P-chalcogenide derivatives Ph2P(E)fcSbPh2 (1E, fc = ferrocene-1,1'-diyl, E = O, S, Se) were synthesized and further converted to the corresponding stiboranes Ph2P(E)fcSb(O2C6Cl4)Ph2 (6 and 6E) by oxidation with o-chloranil. All compounds were characterized by spectroscopic methods, X-ray diffraction analysis, cyclic voltammetry, and theoretical methods. Both NMR spectroscopy and DFT calculations confirmed the presence of P → Sb and P═O → Sb donor-acceptor interactions in 6 and 6O, triggered by the oxidation of the stibine moiety into Lewis acidic stiborane. The corresponding interactions in 6S and 6Se were of the same type but significantly weaker. A coordination study with AuCl as the model metal fragment revealed that the phosphine group acts as the "primary" coordination site, in line with its higher basicity. The obtained Au(I) complexes were applied as catalysts in the Au-catalyzed cyclization of N-propargylbenzamide and in the oxidative [2 + 2 + 1] cyclization of ethynylbenzene with acetonitrile and pyridine N-oxides. The catalytic results showed that the stibine complexes had worse catalytic performance than their phosphine counterparts, most likely due to the formation of weaker coordination bonds and hence poorer stabilization of the active metal species. Nevertheless, the stibine moiety could be used to fine-tune the properties of the ligated metal center by changing the oxidation state or substituents at the "remote" Sb atom.

Nickel and Palladium Complexes of a PP(O)P Pincer Ligand Based upon a peri-Substituted Acenaphthyl Scaffold and a Secondary Phosphine Oxide

A PP(O)P pincer ligand based upon a peri-substituted acenaphthyl (Ace) scaffold and a secondary phosphine oxide, (5-Ph₂P-Ace-6-)₂P(O)H, was prepared and fully characterized including a neutron diffraction study. The reaction with [Ni(H₂O)₆]Cl₂ and PdCl₂ produced ionic metal(II) complexes [κ³-P,P',P''((5-Ph₂P-Ace-6-)₂P(OH))MCl]Cl, which upon addition of Et₃N gave rise to zwitterionic metal(II) complexes κ³-P,P',P''((5-Ph₂P-Ace-6-)₂P(O))MCl (M = Ni, Pd). The reaction with Ni(COD)₂ (COD = cyclooctadiene) provided the η³-cyclooctenyl Ni(II) complex κ³-P,P',P''((5-Ph₂P-Ace-6-)₂P(O))Ni(η³-C₈H₁₃). A detailed complementary bonding analysis of the P-H, P-O, and P-M interactions was carried out (M = Ni, Pd).

Structure of a diorganotelluroxonium(IV) cation, {[2,6-(CH2NMe2)2C6H3Te(μ-O)]2}2+, with the tri-chlorido-(dimethyl sulfoxide)-platinum(II) anion

In the title salt, di-μ-oxido-bis-{2,6-bis-[(di-methyl-amino)-meth-yl]phenyl-κC ¹}tellurium(-IV) bis[tri-chlorido-(dimethyl sulfoxide-κS)platinate(II)], (C₂₄H₃₈N₄O₂Te₂)[PdCl₃(C₂H₆OS)]₂, which crystallizes in the triclinic space group P , each Te atom is in a distorted five-coordinated TeO₂N₂C square-pyramidal geometry (τ values of 0.026 and 0.001) with the C atoms of the phenyl rings occupying the apical positions. The phenyl rings in the [C₂₄H₃₈N₄O₂Te₂]²⁺ cation are in a cis arrangement to enable this species to participate in Te⋯Cl cation-anion inter-actions. There are also C-H⋯O inter-actions involving the dimethyl sulfoxide ligands and numerous cation-anion and anion-anion C-H⋯Cl inter-actions, which link the ions into a complex three-dimensional array.

Reaction of imidazoline-2-selone derivatives with mesityltellurenyl iodide: a unique example of a 3c-4e Se→Te←Se three-body system embedding a tellurenyl cation

1,2-Bis(3-methyl-4-imidazolin-2-selone)ethane was used to stabilize the first example of an authentic mesityltellurenyl cation, [MesTe]⁺, as a charge transfer adduct featuring a 3c-4e Se→Te←Se three-body system.

Transmetallation of bis(6-diphenylphosphinoxy-acenapth-5-yl)mercury with tin tetrachloride, antimony trichloride and bismuth trichloride

The synthesis and structure of well-defined arylelement chlorides RSnCl₄, RSnCl₃·THF, RSbCl₂, RSbCl₂·THF and RBiCl₂ is reported (R = 6-diphenylphosphinoxy-acenapth-5-yl).

A Monoaryllead Trichloride That Resists Reductive Elimination

Transmetallation of Pb(OAc)₄ with R₂ Hg (1), followed by treatment with HCl in Et₂ O, provided RPbCl₃ (2), the first kinetically stabilized monoorganolead trihalide that resists reductive elimination under ambient conditions. The kinetic stabilisation relies on an intramolecularly coordinating O-donor substituent (R=6-Ph₂ P(O)-Ace-5-). The gram-scale preparation of 2 was key for the synthesis of unsymmetrically substituted diaryllead dichlorides RR'PbCl₂ (3 a, R'=Ph; 3 b, R'=4-MeOC₆ H₄ ; 3 c, R'=4-Me₂ NC₆ H₄ ).