13750-62-4Relevant articles and documents
Structural characterization of a new cobalt(II) complex of 1-benzyl-5-methyl-1H-imidazole
Bouchouit,Bouraiou,Bouacida,Belfaitah,Merazig
, p. 835 - 839 (2016)
The preparation of a cobalt(II) chloride complex with a N-donor ligand 1-benzyl-5-methyl-1H-imidazole of formula [CoCl2(1-benzyl-5-methyl-1H-imidazole)2] is described. The isolated complex was characterized by UV, IR spectroscopy and crystallographic studies. Single crystal X-ray diffraction analysis of the complex reveals its monomeric tetra-coordinated nature. The coordination polyhedron around the cobalt center can be described as a quasi-regular tetrahedron. The Co–N distances for this compound are 2.0111(17) ? and 2.0118(17) ?, while the Co–Cl distances are 2.2582(7) ? and 2.2549(7) ?. The crystal packing can be described as layers parallel to (101) plane alternating along the b axis, and it is stabilized by π–π stacking between the imidazole and phenyl rings. The shortest centroid–centroid distance is 3.6002(14) ?.
Atom Transfer Radical Polymerization-Inspired Room Temperature (sp3)C-N Coupling
Coote, Michelle L.,Fung, Alfred. K. K.,Sherburn, Michael S.,Yu, Li-Juan
, p. 9723 - 9732 (2021/07/20)
A simple nonphotochemical procedure is reported for Cu(I)-catalyzed C-N coupling of aliphatic halides with amines and amides. The process is loosely based on the Goldberg reaction but takes place readily at room temperature. It uses Cu(I)Br, a commonly used and inexpensive atom transfer radical polymerization precatalyst, along with the cheap ligand N,N,N′,N″,N″-pentamethyldiethylenetriamine, to activate the R-X bond of the substrate via inner-sphere electron transfer. The procedure brings about productive C-N bond formation between a range of alkyl halide substrates with heterocyclic aromatic amines and amides. The mechanism of the coupling step, which was elucidated through application of computational methods, proceeds via a unique Cu(I) → Cu(II) → Cu(III) → Cu(I) catalytic cycle, involving (a) inner-sphere electron transfer from Cu(I) to the alkyl halide to generate the alkyl radical; (b) successive coordination of the N-nucleophile and the radical to Cu(II); and finally reductive elimination. In the absence of a nucleophile, debrominative homocoupling of the alkyl halide occurs. Control experiments rule out SN-type mechanisms for C-N bond formation.
Imidazole-Bridged Tetrameric Group(IV) Heteroleptic Complexes from the Spontaneous Metal-Ligand Assembly of a Potentially N4-Tetradentate Ligand
Luconi, Lapo,Tuci, Giulia,Yakhvarov, Dmitry,Poli, Giovanni,Rossin, Andrea,Khusnuriyalova, Aliya,Giambastiani, Giuliano
, p. 4384 - 4393 (2019/09/17)
The imidazole-containing N4-tetradentate ligand N-(2-(1H-imidazol-2-yl)-3-(pyridin-2-yl)propyl)-2,6-diisopropylaniline (L2H) and its N-benzyl-protected variant (L2Bn) at the imidazole fragment have been synthesized and fully characterized. Both molecules contain an unresolved Csp3 stereogenic center. The coordination behavior of the newly prepared ligands towards group IV metal ions (MIV = Zr, Hf) has been examined through multinuclear 1H and 13C{1H} NMR spectroscopy and selected single-crystal X-ray structural analyses. The ability of the imidazole fragment to enter the metal coordination sphere as a neutral or a monoanionic system has also been investigated, unveiling quite original coordination modes as well as unexpected molecular architectures. When one N imidazole atom is blocked by a benzyl protecting group (L2Bn), the ligand reaction with MIV(NMe2)4 (MIV = Zr, Hf) as metal precursor gives rise to discrete monometallic tris(dimethylamido) 5-coordinated compounds of general formula L2BnM(NMe2)3. The ligand chelates the metal ion as a bidentate monoanionic κ2{N–,N} system through the imidazole moiety and the anilido N donor while an uncoordinated picolyl arm dangles away from the metal center. Upon coordination to the metal ion, the unprotected L2H undergoes a unique self-assembly of the chiral racemic ligand to generate an achiral tetrameric network featuring a regularly alternating (R*,S*,R*,S*) configuration around the 6-coordinated metal centers. The resulting bis(dimethylamido) tetrameric architectures of formula [L2HM(NMe2)2]4 named “poker complexes” contain the imidazole fragment of each ligand bridging two adjacent MIV ions in a μ-κ{N}:κ{N–} coordination hapticity. At the same time, the picolyl fragments of each chelating L2H ligand “sting” a neighboring metal center as unconventional scorpion's tails that impose further rigidity to the tetrameric structure.
