Synthesis, Spectroscopy, and Redox Studies of Ferrocene-Functionalized Coinage Metal Alkyne Complexes

Abstract

Ethynylferrocene (FcCCH) was utilized as a redox-active metalloligand for the synthesis of polynuclear coinage metal complexes. The reaction of [FcCCLi] with tri-tert-butylphosphine metal chlorides [tBu3P-MCl] (M = Au, Ag, Cu) yielded different heteronuclear ferrocene-funtionalized alkyne complexes featuring metallophilic interactions. Furthermore, the redox properties of the ferrocenyl-functionalized tetracopper complex were investigated by cyclic voltammetry and UV–vis–near-IR spectroelectrochemistry. They indicate the compounds’ redox-rich nature and a weak electronic coupling between the redox-active ferrocenyl units over a large distance.

Exploring the Synthesis and Coordination Chemistry of Pentafluorophenylcopper: Organocopper Polyanions and Coordination Networks

“…The Cu 4 units with adjacent donors show a twist in the Cu 4 plane (torsion Cu1–Cu2–Cu3–Cu4 = 10.86(2)°; see Figure ), in contrast to the flat Cu 4 geometry of those with opposite donors. In all cases, the trans -tetramer Cu···Cu distances are greater than 3 Å, and the Cu 4 geometry is not significantly compressed into a rhombus as has been observed with other donors such as toluene. , To the best of our knowledge, there are no other reported examples of two donors selecting an adjacent binding arrangement onto neighboring coppers of a planar organocopper tetramer, with all other examples displaying coordination to opposite Cu sites. ,,− The Cu–O distances range between 2.159(2) and 2.247(2) Å, slightly longer than the Cu–THF bond lengths observed in [Cu 16 (CCCCTrip) 16 (THF) 4 ] (2.04(2)–2.15(4) Å) . In solution, the 19 F NMR chemical shifts of the C 6 F 5 group in 1 shift upfield as increasing equivalents of dioxane are added to a solution of 1, and the Δδ m , p distance decreases, in line with increasing interaction with a donor species (Table S1, Figure S7).…”

“…x = 2 or 3, see Fig S22). In keeping with reported donor interactions to [CuR]4 units, 17,32,[41][42][43][44] and the solid-state structure of 1-diox it is anticipated that x is most likely equal to two and the expected formula in solution is [CuC6F5]4(dioxane)2. We investigated the possible synthesis of 1 in THF, a slightly more polar and more strongly donating solvent than Et2O, but a preferred solvent for the synthesis of other organocopper species such as mesitylcopper.…”

“…19 F DOSY NMR spectroscopy data comparing 1 with 1 + excess dioxane are consistent with multiple donor molecules per Cu tetramer for the latter (e.g., x = 2 or 3; see Figure S22). In keeping with reported donor interactions to [CuR] 4 units, ,,− and the solid-state structure of 1-diox , it is anticipated that x is most likely equal to 2 and the expected formula in solution is [CuC 6 F 5 ] 4 (dioxane) 2 .…”

“…17,32 To the best of our knowledge, there are no other reported examples of two donors selecting an adjacent binding arrangement on to neighbouring coppers of a planar organocopper tetramer, with all other examples displaying coordination to opposite Cu sites. 17,32,[41][42][43][44] The Cu−O distances range between 2.159(2) and 2.247(2) Å, slightly longer than the Cu−THF bond lengths observed in [Cu16(C≡CC≡CTrip)16(THF)4] (2.04(2)-2.15(4)Å). 39 In solution, the 19 F NMR chemical shifts of the C6F5 group in 1 shift upfield as increasing equivalents of dioxane are added to a solution of 1 and the Δδm,p distance decreases, in line with increasing interaction with a donor species (Table S1, Fig S7).…”

Investigating a Redox Active Samarium Complex in Catalytic Reactions

“…The synthesis of this ethynyl ferrocene bis(diisopropylphenyl)amidine [Fc−C≡C‐{C(Ndipp) 2 H}] was achieved through an in situ lithiation of ethynyl ferrocene, [28–29] which was followed by subsequent reaction with bis(diisopropylphenyl)carbodiimide (Scheme 2). [1,15,30] The resulting lithium compound was protonated and recrystallized from hot toluene.…”