Syntheses and structures of Li, Fe, and Mo derivatives of N,N′-bis(2,6-diisopropylphenyl)-o-phenylenediamine

Abstract

Double deprotonation of N,N'-bis(2,6-diisopropylphenyl)-o-phenylenediamine (H2L) with n-BuLi in THF yields the dilithium complex Li2L(thf)3. The reaction of Li2L(thf)3 with FeBr2(thf)2 and subsequent replacement of the solvent with toluene yield LFe(η(6)-toluene), which can also be synthesized from Fe(HMDS)2(thf) and H2L in toluene. The NMR data, bond lengths obtained from an X-ray diffraction study, and DFT calculations indicate that the diamide ligand L(2-) undergoes oxidization to a radical ligand L(1-). Reaction of LFe(η(6)-toluene) with 1 atm CO yields the tricarbonyl complex LFe(CO)3. MoCl4(thf)2 reacts with two equivalents of Li2L(thf)3 to yield (LiL)2MoCl2(thf)4 in which the phenylene backbone of the ligand has been dearomatized. One-electron oxidation of Li2L(thf)3 by EuCl3(dme)2 yields the open-shell species LiL(OEt2), which was characterized by X-ray crystallography and EPR spectroscopy.

Electrophilic Iron Catalyst Paired with a Lithium Cation Enables Selective Functionalization of Non‐Activated Aliphatic C−H Bonds via Metallocarbene Intermediates

“…[18] In agreement with the electronic structures suggested by X-ray crystallography, 1 HNMR characterization in C 6 D 6 solution displayed different magnetic behavior for the two complexes.T he compound 4 is diamag-netic and its spectrum displays six signals in the range d = 7-2ppm, assigned to the N,N'-chelating ligand, and four highly shielded resonances (d = 5.14, 4.89 and 4.82 and 1.78 ppm) consistent with a h 6 -toluene adduct. [18] In agreement with the electronic structures suggested by X-ray crystallography, 1 HNMR characterization in C 6 D 6 solution displayed different magnetic behavior for the two complexes.T he compound 4 is diamag-netic and its spectrum displays six signals in the range d = 7-2ppm, assigned to the N,N'-chelating ligand, and four highly shielded resonances (d = 5.14, 4.89 and 4.82 and 1.78 ppm) consistent with a h 6 -toluene adduct.…”

“…Using the electron-rich para-methoxy aryl diazoester reagent 9 led to the corresponding cyclopentane product 9a in ahigh yield of 70 %u pon isolation, while the electron-poor parachloro-substituted compound 10 was transformed into 10 a in adiminished 39 %yield upon isolation (Table 3). [a] Reaction conditions: [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] = 0.08 mm.C onversions of 6-8 were determined by 1 HNMR spectroscopy using dibromomethane as an internal standard. )7 7:23.…”

Electronic and Geometric Structures of Paramagnetic Diazadiene Complexes of Lithium and Sodium

“…On the basis of the findings on the size dependency of the metal‐site contribution, it was derived that elements in the alkali‐metal group that are bigger in size, such as the radical structures of Cs + and Rb + , would mainly consist of ligand‐centered contributions. Indeed, it was found that radicals of Cs + – and Rb + –diamine complexes adopted a ligand‐centered nature …”

Linear, Trinuclear Cobalt Complexes with o‐Phenylene‐bis‐Silylamido Ligands

“…Although L1 – L4 have been employed as spectator ligands on electropositive, or high oxidation state (OS) transition (Zr, Nb, Ta, Mo, W) and main group metals, their additional versatility stems from potential redox non‐innocence that could be manifested by the occurrence of (semi)oxidized redox states (i.e., o ‐diiminosemiquinonato‐ and o ‐diiminoquinone) . Recently, in the realm of 3d metals, redox non‐innocence of L1–L4 type ligands has been implicated in stoichiometric and catalytic reactivity and the characterization of unusual formal OS . In the parent L5 , different redox states have been assigned by structural and spectroscopic techniques .…”

“…[8] Recently,i nt he realm of 3d metals, redox non-innocence of L1-L4 type ligands hasb een implicated in stoichiometric [9] and catalytic [8c] reactivity and the characterization of unusual formal OS. [10] In the parent L5,d ifferent redoxs tates have been assignedb ys tructurala nd spectroscopict echniques. [11] Furthermore,p re-organized ligand scaffolds comprising o-phenylene-N-alkyl-N'-(trialkylsilyl)amides have been used for the stabilization of homo-a nd hetero-metallic 3d metal clusters.…”