Palladium(II) Complexes Containing a Pyridinyliminophosphorane Ligand

Abstract

A series of new pyridinyliminophosphorane bidentate ligands with different steric environments [(2-C 6 H 4 N)PPh 2 = NAr (NPN)] and their methylpalladium complexes [PdClMe(NPN)] were prepared. From the crystal structure analysis it is evident that the alkyl ligands are always trans to the pyridinyl nitrogen donor, revealing a σ-donating abil-

Palladium (II) complexes chelated by 1‐substituted‐4‐pyridyl‐1H‐1,2,3‐triazole ligands as catalyst precursors for selective ethylene dimerization

“…For instance, the Pd–N(1) bond distance of complex C1 [ 2.1785 (19) Å] is remarkably longer than Pd–N(2) owing to the trans influence exerted by the Pd–Me fragment. Similar trends were observed for other reported bidentate palladium methyl complexes . The Pd–N(Py) bond length of the complexes is influenced by the substituent on the pyridyl‐ring.…”

Synthesis, Structure, Reactivity, and Catalytic Activity of C,N‐ and C,N,N‐Orthopalladated Iminophosphoranes

“…The (5) or neutral ligands (6)(7)(8)(9)(10) shows that the five-membered orthometallated iminophosphorane is quite stable, and behaves similarly to other C,N-orthometallated complexes derived from different amines. The reactivity of 11 shows that the bonding of the terdentate ligand [C 6 H 4 -2-PPh 2 =N-C(O)-2-NC 5 H 4 -κ-C,N,N] to the Pd atom is remarkably stable.…”

“…In summary, the reactivity of 1 in cleavage reactions with neutral ligands (2-4) or substitution reactions of the halide bridging system by anionic (5) or neutral ligands (6)(7)(8)(9)(10) shows that the five-membered orthometallated iminophosphorane is quite stable, and behaves similarly to other C,Northometallated complexes derived from different amines. However, the reactivity of complex 11, which contains a C,N,N-terdentate ligand reveals some noteworthy differences.…”

“…the aza-Wittig reaction), either as neutral or as anionic reagents. [1][2][3] In addition, the bonding properties of these compounds as ligands towards transition metals are still attracting the interest of chemists, for several reasons: their ability to form and to stabilize carbene complexes, [5,8] the easy modulation of the electronic and steric properties of different types of catalysts (for instance, in oligo-and polymerisation of ethylene, [4,6,23] hydrogen-transfer processes, [9,10] etc. ), their applications in enantioselective synthesis and catalysis (allylic substitution), [25,26] the synthesis of alkaline earth organometallic complexes, [7] and, in general, due to their versatility.…”

Homo‐ and copolymerization of ethylene and norbornene with bis(β‐diketiminato) titanium complexes activated with methylaluminoxane

“…Neutral nickel complexes containing bidentate [P,O] chelating ligands were efficient catalysts for the copolymerization of NB with ethylene, and essentially alternating ethylene–NB (E–N) copolymer was obtained 20. The cationic palladium complexes bearing a pyridinyliminophosphorane ligand produced E–N copolymers with high incorporated content of NB 22. Kaminsky and coworkers23, 24 reported on E–N copolymerization with a series of palladium α‐diimine catalysts, and a alternating copolymer was obtained.…”