Terminal Iron Dinitrogen and Iron Imide Complexes Supported by a Tris(phosphino)borane Ligand

Reactivity and Properties of Metal Complexes Enabled by Flexible and Redox-Active Ligands with a Ferrocene Backbone

“…[59][60][61]78 Due to the high acidity of the phenolic proton of H 2 (OEEO fc ), the installation of the metal fragment was facile; the choice of synthetic routes was mainly based on the desired composition of the pre-catalysts used for polymerization and the ease of availability of a metal precursor. Group 4 metal complexes supported by salfan, thiolfan, and thiolfan* ligands were prepared in a similar way using Zr(OtBu) 4 or Ti(OiPr) 4 as metal precursors. 43 In addition, the group 13 metal complex (salfen)In(OtBu) was prepared through salt metathesis between InCl 3 and K 2 (salfen) followed by treating (salfen)InCl with KOtBu, 38 while late transition metal complexes such as M(salfen) (M = Co, Zn) were also prepared by salt metathesis from the corresponding metal chlorides.…”

“…Noticeable examples include N-heterocyclic carbenes with a tethered anionic anchor (Chart 1a) 1,2 and XP 3 type (X = B or N) triphosphine ligands with an additional donor X in the backbone (Chart 1b). 3,4 When the former coordinate to electropositive metals, the N-heterocyclic carbene acts as a labile donor that can readily dissociate. 5 When the latter bind to late transition metals, the metal-X distance may vary according to the change in the coordination environment around the metal.…”

A Triad of Highly Reduced, Linear Iron Nitrosyl Complexes: {FeNO}8–10

“…This yielded redbrown crystalline material of {TPBFeNO} 9 (yield = 21.3 mg, 68%). 1 10 - [TPBFeNO][PF]6 (66.3 mg, 0.081 mmol, 1.0 eq.) was suspended in THF (10 mL) and added to a vial containing 1% Na/Hg amalgam (3.8 mg of Na, 0.162 mmol, 2.0 eq.).…”

“…of Na/Hg and the above reported isolation procedure also led reproducibly to pure material. 1 H NMR (-78 °C, THF-d8, 500 MHz): δ = 7.15 (3 H, br s, Ar-H), 7.01 (3 H, br s, Ar-H), 6.73 (3 H, br s, Ar-H), 6.59 (3 H, br s, Ar-H), 3.74 (32 H, s, 12-c-4), 2.79 (3 H, br s, PCH), 2.00 (3 H, br s, PCH), 1.52-0.80 (27 H, m, PCHCH3), -0.43 (9H, s, PCHCH3). 31 P NMR (-78 °C, THF-d8, 202 MHz): δ = 88.7 (br).…”

“…At room temperature there is no detectable 31 P NMR signal and the 1 H NMR spectrum is broadened presumably by the presence of undetectably small amounts of {TPBFeNO} 9 that undergoes fast electron transfer with {TPBFeNO} 10 in solution. Cooling the solution to -78 °C makes this process slower than the NMR time scale allowing 1 10 and then pulling vacuum on it before dissolution in THF-d8 leads to the presence of 0.5 equivalents of C6H6 as seen in Figure S9. The crystal structure of {TPBFeNO} 10 has two half-occupied benzene molecules present confirming the presence of benzene in crystalline {TPBFeNO} 10 .…”