Four- and five-coordinate nickel(ii) complexes bearing new diphosphine–phosphonite and triphosphine–phosphite ligands: catalysts for N-alkylation of amines

Abstract

A series of nickel(ii) complexes supported by the new tridentate P3 and tetradentate P4 ligands act efficiently as catalysts for the N-alkylation of primary amines with alcohols.

New nickel(ii) Schiff base complexes as potential tools against SARS-CoV-2 Omicron target proteins: an in silico approach

“…As expected, for the four-coordinate d 8 metal complexes, the structure of the Ni( ii ) complex [Ni(L 1 )][(PPh 3 )]DMF ( 1 ) adopts a nearly ideal square planar geometry with O(1)–(Ni(1))–O(2) and N(1)–Ni(1)–P(1) bond angles of 176.57(9)° and 172.96(6)°, respectively. 54,55 The other angles around the Ni( ii ) atom deviate slightly from the ideal value (90°), ranging from 86.83(8)° to 94.48(8)°. The Ni–P, Ni–O and Ni–N bond distances are in the usual range in Ni( ii ) complex ( 1 ).…”

Complexes of Ni(II) with triphosphine‐phosphite ligand P(OCH2PPh2)3: syntheses, structures, and electronic properties

“…[25,37] Structure of complex [P(OCH 2 PPh 2 ) 3 NiCl]PF 6 was reported recently. [22] This complex contains the same cation as our complex 2•CH 3 OH, but it was reported to crystalize in a different space group (P2 1 3) than that observed by us in 2 (P2 1 2 1 2 1 ). Since complexes 2•CH 3 OH and 3•CH 3 OH are isomorphous, thermal ellipsoid plot of only one of them, 2•CH 3 OH is shown in Figure 3.…”

“…In line with these observations, when NiCl 2 was reacted with 1 in the presence of KPF 6 crystalline product [(P(OCH 2 PPh 2 ) 3 )NiCl]PF 6 was obtained. [22] We conducted our reactions using equimolar (0.5 : 0. Different type of reactivity was observed when ligand 1 was reacted with nickel salts containing non-halide anions (Ni(NO 3 ) 2 , Ni(CH 3 COO) 2 ), or Ni(BF 4 ) 2 ).…”

“…A new PP 3 ligand, a phosphite/triphosphine P(OCH 2 PPh 2 ) 3 (Figure 1, 1) has been reported recently. [22] Coincidentally, during the last several years we have been investigating coordination chemistry of this same ligand as well. [23] When reacted with equimolar mixtures of nickel halide and tetrafluoroborate salts, ligand 1 coordinated to cationic NiÀ Cl and NiÀ Br fragments forming trigonal bipyramidal complexes 2 and 3 (Figure 1).…”

Roles of Alkali Metals tert‐Butoxide as Catalysts and Activators in Organic Transformations

“…Very recently, Panigrahi and co‐workers [78] have developed diphosphine‐phosphonite as well as triphosphine‐phosphite ligands having tridentate and tetra‐dentate capacities respectively, and their corresponding complexes built upon 3d metal Nickel (II) core. The structure and flexibility of the complexes bearing the above‐mentioned ligands have been determined by single‐crystal XRD.…”