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Despite their connection to ammonia synthesis, little is known about the ability of iron‐bound, bridging nitrides to form N−H bonds. Herein we report a linear diiron bridging nitride complex supported by a redox‐active macrocycle. The unique ability of the ligand scaffold to adapt to the geometric preference of the bridging species was found to facilitate the formation of N−H bonds via proton‐coupled electron transfer to generate a μ‐amide product. The structurally analogous μ‐silyl‐ and μ‐borylamide complexes were shown to form from the net insertion of the nitride into the E−H bonds (E=B, Si). Protonation of the parent bridging amide produced ammonia in high yield, and treatment of the nitride with PhSH was found to liberate NH3 in high yield through a reaction that engages the redox‐activity of the ligand during PCET. [ABSTRACT FROM AUTHOR]

The first example of a structurally characterized titanium methylidene, (PN)2Ti=CH2, has been prepared via one-electron oxidation of (PN)2Ti(CH3) followed by deprotonation or by H-atom abstraction using an aryloxyl radical. The Ti=C distance was found to be 1.939(3) Å, and variable temperature, multinuclear, and multidimensional NMR spectroscopic experiments revealed the methylidene to engage in long range interactions with protons on the ligand framework. Computational studies showed that the Ti=C bond, which until now has eluded structural studies, displays all the hallmarks of a prototypical Schrock-carbene. [ABSTRACT FROM AUTHOR]

Triarylborane Lewis acids bind [Fe2(pdt)(CO)4(CN)2]1 [1]2- (pdt2- = 1,3-propanedithiolate) and [Fe2(adt)CO4(CN)2]2- [3]2- (xdt2- = 1,3-azadithiolate, HN(CH2S-)2) to give the 2:1 adducts [Fe2(pdt)(CO)4(CNBAr3)2]2-. Attempts to prepare the 1:1 adducts [1(BAr3)]2- (Ar = Ph, C6F5) were unsuccessful, but related 1:1 adducts were obtained using the bulky borane B(C6F4-o-C6F5)3 (BArF*3). By virtue of the N-protection by the borane, salts of [Fe2(pdt)(CO)4(CNBAr3)2]2- sustain protonation to give hydrides that are stable (in contrast to [H1]-). The hydrides [H1(BAr32]- are 2.5-5 pKa units more acidic than the parent [H1]-). The adducts [1(BAr3)2]2-) oxidize quasi-reversibly around -0.3 V versus Fc0/+ in contrast to ca. -0.8 V observed for the [1]2-/- couple. A simplified synthesis of [1]2-, [3]2-, and [Fe2(pdt)(CO)5(CN)]- ([2]-) was developed, entailing reaction of the diiron hexacarbonyl complexes with KCN in MeCN. [ABSTRACT FROM AUTHOR]