N 2-o-Tolyl­benzamidine

The asymmetric unit of the title compound, C14H14N2, contains two independent mol­ecules with slightly different conformations; the dihedral angles formed by aromatic rings in the two mol­ecules are 73.2 (1) and 75.0 (1)°. Inter­molecular N—H⋯N hydrogen bonds link the mol­ecules into chains extended in the [100] direction

1,3-Bis(2,6-diisopropyl­anilino)-1-phenyl­butyl­ium hexa­fluorido­phosphate

The cation of the title salt, C34H45N2 +·PF6 −, is a protonated form of an unsymmetrical overcrowded β-imino­amine. The observed bond lengths [C—N = 1.326 (4)–1.341 (4) Å and C—C = 1.383 (4)–1.391 (4) Å] suggest significant delocalization within the π system of the N C C C N backbone

The Formazanate Ligand as an Electron Reservoir: Bis(Formazanate) Zinc Complexes Isolated in Three Redox States

The synthesis of bis(formazanate) zinc complexes is described. These complexes have well-behaved redox-chemistry, with the ligands functioning as a reversible electron reservoir. This allows the synthesis of bis(formazanate) zinc compounds in three redox states in which the formazanate ligands are reduced to "metallaverdazyl" radicals. The stability of these ligand-based radicals is a result of the delocalization of the unpaired electron over four nitrogen atoms in the ligand backbone. The neutral, anionic, and dianionic compounds (L2Zn0/-1/-2) were fully characterized by single-crystal X-ray crystallography, spectroscopic methods, and DFT calculations. In these complexes, the structural features of the formazanate ligands are very similar to well-known β-diketiminates, but the nitrogen-rich (NNCNN) backbone of formazanates opens the door to redox-chemistry that is otherwise not easily accessible. N is better than C: Bis(formazanate) zinc complexes (see picture; Zn yellow, N blue, O red, Na green) show sequential and reversible redox chemistry in which the formazanate ligands are reduced to metallaverdazyl radicals. These ligands are very similar to β- diketiminates, but the nitrogen-rich NNCNN backbone of formazanates opens the door to redox chemistry that is otherwise difficult to access

N-[3-(2,6-Dimethylanilino)-1-methylbut-2-enylidene]-2,6-dimethylanilinium chloride1

The title salt, C21H27N2 +·Cl− resulted from the condensation between 2,6-dimethyl­aniline and acetyl­acetone in acidified ethanol. The bulky cation is stabilized in a β-imino­enamine tautomeric form, and presents a W-shaped conformation. The benzene rings are arranged almost parallel, with a dihedral angle of 6.58 (4)° between the mean planes. Both N—H groups in the cation form strong hydrogen bonds with two symmetry-related chloride anions. The resulting supra­molecular structure is a one dimensional polymer running along [001], alternating cations and anions. The π–π inter­action observed in the mol­ecule, characterized by a centroid–centroid separation of 4.298 (4) Å, is thus extended to the chains, with separations of 5.222 (4) Å between benzene rings of neighbouring cations in the crystal

β-Diketonate, β-Ketoiminate, and β-Diiminate Complexes of Difluoroboron

A series of β-diketonate, keto(aryl)iminato, and β-bis(aryl)iminato complexes of difluoroboron, twenty in total, have been prepared to assess the impact of chelate ring and aniline substitution on the structural, electrochemical, and photophysical properties of these ubiquitous chelates. DFT (B3LYP/6-31G*) calculations supplemented the experimental results and both demonstrated that replacing oxygen with the more electron-donating aniline groups serves to only fine-tune the electronic properties because both the HOMO and LUMO energies are affected by such substitution. The electronic properties of all compounds are most greatly influenced by the nature of the substituents bound to the carbon portion of the chelate ring. Each difluoroboron complex undergoes two ligand-based, one-electron reductions where the first reduction potential becomes less favorable with increasing aniline substitution. Similarly, replacing oxygen with the more electron-donating aniline groups gives rise to slightly red-shifted absorption and emission processes. Substitution on the aniline ring has little, if any, influence on the electronic properties of the resultant complexes

Reversible ligand-centered reduction in low- coordinate iron formazanate complexes

Coordination of redox‐active ligands to metals is a compelling strategy for making reduced complexes more accessible. In this work, we explore the use of redox‐active formazanate ligands in low‐coordinate iron chemistry. Reduction of an iron(II) precursor occurs at milder potentials than analogous non‐redox‐active β‐diketiminate complexes, and the reduced three‐coordinate formazanate‐iron compound is characterized in detail. Structural, spectroscopic, and computational analysis show that the formazanate ligand undergoes reversible ligand‐centered reduction to form a formazanate radical dianion in the reduced species. The less negative reduction potential of the reduced low‐coordinate iron formazanate complex leads to distinctive reactivity with formation of a new N−I bond that is not seen with the β‐diketiminate analogue. Thus, the storage of an electron on the supporting ligand changes the redox potential and enhances certain reactivity