Abstract:Treatment of the Schiff base ligand 2,3,4‐(MeO)3C6H2C(H)=N[2‐(OH)‐5‐tBuC6H3] (a) with palladium(II) acetate in toluene gave the cyclometallated complex [Pd{2,3,4‐(MeO)3C6HC(H)=N(2‐O‐5‐tBuC6H3)}]4 (1a) with the tridentate ligand [C,N,O]. The complex showed a tetranuclear arrangement of the cyclometallated monomers with a P4O4 core. Reaction of 2,6‐(Me)2C6H3C(H)=N[2‐(OH)C6H4] (b) and 2,5‐(Me)2C6H3C(H)=N[2‐(OH)C6H4] (c) with palladium(II) acetate under similar conditions yielded the tetranuclear complexes [Pd{6‐M… Show more
“…Therefore, the core of the tetrameric molecule consists of an eight-membered ring of alternating palladium and oxygen atoms. The Pd-C [1.968 (3) [20,19,[21][22][23]. The B-O and B-C distances are similar to previously reported values [12].…”
“…Therefore, the core of the tetrameric molecule consists of an eight-membered ring of alternating palladium and oxygen atoms. The Pd-C [1.968 (3) [20,19,[21][22][23]. The B-O and B-C distances are similar to previously reported values [12].…”
“…There is essentially no deviation (0.002(1)–0.005(3) Å) of the metal centre from the plane (rmsd 0.008–0.035 Å) constituted by the four coordinating atoms. In general, the metal to coordinating atom bond lengths are unexceptional and comparable with the corresponding bond lengths observed in mononuclear palladium(II) complexes containing similar coordinating atoms …”
Reactions of 1-((2-hydroxy-5-R-phenylimino)methyl)naphthalen-2-ols (H 2 L n , n = 1-3 for R = H, Me, Cl, respectively) with [Pd(PPh 3 ) 2 Cl 2 ] and Et 3 N in toluene under reflux produced three new mononuclear square-planar palladium(II) complexes with the general formula [Pd(L n )(PPh 3 )] (1, R = H; 2, R = Me; 3, R = Cl). All the complexes were characterized using elemental analysis, solution conductivity and various spectroscopic (infrared, UV-visible and NMR) measurements. Molecular structures of 1-3 were confirmed using single-crystal X-ray diffraction analysis. In each complex, the fused 5,6-membered chelate rings forming phenolate-O, azomethine-N and naphtholate-O donor (L n ) 2À and the PPh 3 form a square-planar ONOP coordination environment around the metal centre. Infrared and NMR spectroscopic features of 1-3 are consistent with their molecular structures. Electronic spectra of the three complexes display several strong primarily ligand-centred absorption bands in the range 322-476 nm. All the complexes were found to be effective catalysts for carbon-carbon cross-coupling reactions of arylboronic acids with aromatic and heteroaromatic aldehydes to form the corresponding diaryl ketones.
“…Since the properties of such complexes are heavily influenced by the nature of the ligands [10], much attention has been given to the design and synthesis of chelating ligands. Tridentate Schiff base ligands often exhibit versatile chelating modes, such as NNN, NNO, NNS and ONO [11][12][13][14][15][16]. Hence, the design and synthesis of such ligands remains an interesting area of current research.…”
A series of transition metal(II) complexes of the type [M(PPQ) 2 ] [PPQ = 2-pyridine-2-yl-3(pyridine-2-methylene-amino)quinazolin-4(3H)-one, M = Co(II), Cu(II), Ni(II), Zn(II), Cd(II)] have been prepared and characterized by IR spectroscopy, elemental analyses and X-ray crystal diffraction. The crystal structure studies revealed diverse coordination behavior of PPQ toward different metal ions, acting as an NNO donor in the cobalt(II) and zinc(II) complexes, but an NNN and NNO mixed donor in the copper(II) and nickel(II) complexes. The metal center generally has an octahedral coordination geometry with the tridentate PPQ ligand, except for the Cd(II) complex in which two PPQ ligands and a nitrate are coordinated (N 4 O 4 ), forming a distorted triangular dodecahedron. The thermal stabilities, luminescence and magnetic properties of these complexes have been studied.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.