Structural and Spectroscopic Studies of the PCP-Bridged Heavy Chalcogen-Centered Monoanions [HC(PPh₂E)(PPh₂)]⁻ (E = Se, Te) and [HC(PR₂E)₂]⁻ (E = Se, Te, R = Ph; E = Se, R = ⁱPr): Homoleptic Group 12 Complexes and One-Electron Oxidation of [HC(PR₂Se)₂]⁻

Bond Stretching and Redox Behavior in Coinage Metal Complexes of the Dichalcogenide Dianions [(SPh2P)2CEEC(PPh2S)2]2− (E=S, Se): Diradical Character of the Dinuclear Copper(I) Complex (E=S)

“…[10] When the solution of 6b is cooled, the resonance at δ 53.1 gradually disappears and at - Figure 2) are cleaved in solution to afford a tetracyclic compound 6b′ (Scheme 2) with inequivalent phosphorus atoms as a part of five-and six-membered rings, respectively. However, the inequivalent phosphorus atoms of a -Ph2PCPPh2-unit in related compounds typically result in two mutually coupled doublets in the 31 P{ 1 H} NMR spectrum owing to the 2 J( 31 P, 31 P) coupling [7,8] and this coupling is not resolved for 6b despite the relatively narrow signals (half-width of ca. 40 Hz at 23 o C).…”

“…[6] Similarly, our recent investigations of the isoelectronic, diseleno monoanion, [HC(PPh2Se)2] − (2), disclosed unusual carbon-centered reactivity. While the metathetical reactions of [Li(TMEDA)]2 with M(II)Cl2 (M = Zn, Hg) afforded the expected homoleptic group 12 complexes with Se,Se'-chelated ligands, [7] an unprecedented selenium-proton exchange combined with a redox disproportionation occurred in reactions with group 14 and 16 element dihalides (M = Sn, Te) to give M(IV) complexes of the novel triseleno dianion [(Se)C(PPh2Se)2] 2− (3a). [8] In a related transformation, mild thermolysis of the mononuclear Hg(II) derivative of 2, Hg[HC(PPh2Se)2]2, produced a dinuclear Hg(II) complex of 3a, [8] while monomeric Pb(II) complexes of 3b and 3c have been attained by chalcogen insertion into the Pb−C bond of dimeric Pb(II) complexes of 1.…”

“…[10] The all-selenium derivative 3a cannot be obtained via this route because of the unavailability of Li2[C(PPh2Se)2] owing to cleavage of P-Se bonds by RLi reagents. [7] Our investigations of the one-electron oxidation of 3b,c generated the novel dichalcogenides, [(SPh2P)2CEEC(PPh2S)2] 2− (4b, E = Se; 4c, E = S), which are formally dimers of the corresponding radical anions [(E)C(PPh2S)2] •− with moderately elongated (by ca. 8 %) central chalcogen-chalcogen bonds.…”

Octahedral Tin(IV) Complexes of the Chalcogen‐Centered Ligands [EC(PPh2S)2]2– (E = S, Se)

“…For comparison, the synthesis of the previously reported all-selenium analogue [Sn{SeC(PPh 2 Se) 2 } 2 ] (1a) [1] by a different route is also illustrated in Scheme 1. Leung and co-workers have shown that the reaction of SnCl 4 with the magnesium reagent MgC(PPh 2 S) 2 (THF) 2 produces the tin(IV) complex Sn[C(PPh 2 S) 2 ] 2 , in which the ligand is bonded in a tridentate (S,C,S) fashion to tin. [10] Interestingly, in this work we isolated small amounts of complex 1b from the reaction of the dilithium reagent Li 2 2 ] (EЈ = S, Se) via chalcogen insertion into Pb-C bonds has been reported previously by Leung et al [11] The 31 P NMR spectra of 1b and 1c in CD 2 Cl 2 show a single resonance at δ = 54.9 and 57.6 ppm, respectively, cf.…”

“…Li 2 [C(PPh 2 Se) 2 ], via double deprotonation of H 2 C(PPh 2 Se) 2 with organolithium reagents is accompanied by P-Se bond cleavage. [4] Preliminary investigations of the metathetical reactions of the new reagents Li 2 [EЈC(PPh 2 S) 2 ] (EЈ = S, Se) with main group metal or metalloid halides have produced heteroleptic complexes of indium(III) and tellurium(IV), [5,6] which have been structurally characterized. Interestingly, redox behavior is observed in the corresponding reactions with CuCl 2 which produce dinuclear Cu I -Cu I complexes of the oxidized ligand involving an elongated central chalcogen-chalcogen bond.…”