Redox and Coordination Behavior of the Hexaphosphabenzene Ligand in [(Cp*Mo)₂(μ,η⁶:η⁶‐P₆)] Towards the “Naked” Cations Cu⁺, Ag⁺, and Tl⁺

Abstract

Although the cyclo-P6 complex [(Cp*Mo)2(μ,η6:η6-P6)] (1) was reported 30 years ago, little is known about its chemistry. Herein, we report a high-yielding synthesis of 1, the complex 2, which contains an unprecedented cyclo-P10 ligand, and the reactivity of 1 towards the “naked” cations Cu+, Ag+, and Tl+. Besides the formation of the single oxidation products 3 a,b which have a bisallylic distorted cyclo-P6 middle deck, the [M(1)2]+ complexes are described which show distorted square-planar (M=Cu(4 a), Ag(4 b)) or distorted tetrahedral coordinated (M=Cu(5)) M+ cations. The choice of solvent enabled control over the reaction outcome for Cu+, as proved by powder XRD and supported by DFT calculations. The reaction with Tl+ affords a layered two-dimensional coordination network in the solid state.

Oxidation Chemistry of Inorganic Benzene Complexes

“…The average P−P bond length in 4 b is 2.177 Å, and similar to 2 a . In contrast, the Cp* derivative 4 d exhibits two significantly elongated P−P bonds (P1−P1’ and P3−P3’) with 2.2474(19) Å and 2.2936(13) Å, whereas the remaining P−P bonds are shortened with 2.1384(10) Å and 2.1347(9) Å compared to neutral 2 b (P−P av 2.183 Å), which represents a bisallylic system. This distortion is by far less pronounced in 4 e containing the Cp Bn ligand (max.…”

“…So far, little is known about the reactivity of isolobal inorganic analogs (E 6 ) of benzene. Although the complex [(Cp*Mo) 2 (μ,η 6 :η 6 ‐P 6 )] has been reported in 1985, the first investigations of its reactivity have been published only recently . This cyclo ‐P 6 complex readily acts as a multidentate ligand towards Ag + , Cu + , and Tl + containing the WCA [Al{OC(CF 3 ) 3 } 4 ] − (=[TEF]) to form layered coordination compounds .…”

“…Althought he complex [(Cp*Mo) 2 (m,h 6 :h 6 -P 6 )] has been reported in 1985, the first investigationso fi ts reactivity have been published only recently. [17,18] This cyclo-P 6 complexr eadily acts as am ultidentate ligand towards Ag + ,C u + ,a nd Tl + containing the WCA [Al{OC(CF 3 ) 3 } 4 ] À (= [TEF]) to form layered coordination compounds. [18] For Cu + ,t hree different reaction products (oxidation, distorted tetrahedral, or square-planar coordination complex) could be selectively obtained by choosing the appropriate solventm ixture of CH 2 Cl 2 and toluene.…”

“…[17,18] This cyclo-P 6 complexr eadily acts as am ultidentate ligand towards Ag + ,C u + ,a nd Tl + containing the WCA [Al{OC(CF 3 ) 3 } 4 ] À (= [TEF]) to form layered coordination compounds. [18] For Cu + ,t hree different reaction products (oxidation, distorted tetrahedral, or square-planar coordination complex) could be selectively obtained by choosing the appropriate solventm ixture of CH 2 Cl 2 and toluene. [18] The Cp derivative [(CpMo) 2 (m,h 6 :h 6 -P 6 )] forms supersandwich complexesb ased on weak HgÀPi nteractions with the trinuclear Lewis acid [(o-HgC 6 F 4 ) 3 ]a nd it forms two-dimensional graphene-like sheets with Cu I halides.…”

“…[18] For Cu + ,t hree different reaction products (oxidation, distorted tetrahedral, or square-planar coordination complex) could be selectively obtained by choosing the appropriate solventm ixture of CH 2 Cl 2 and toluene. [18] The Cp derivative [(CpMo) 2 (m,h 6 :h 6 -P 6 )] forms supersandwich complexesb ased on weak HgÀPi nteractions with the trinuclear Lewis acid [(o-HgC 6 F 4 ) 3 ]a nd it forms two-dimensional graphene-like sheets with Cu I halides. [19,20] Inside these layers,ad istortion of the P 6 rings is observed, with one atom displaced out of the plane.…”