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Condensation reaction of 2-naphthaldehyde with one equivalent of benzohydrazide in presence of acetic acid in refluxing methanol yielded the Schiff base N' -(2-naphthylidene)benzohydrazide (H 2 L) in 86% yield. Reaction of equimolar amounts of Li 2 PdCl 4 (generated in situ from PdCl 2 and LiCl taken in 1:2 mol ratio), H 2 L and NaOAc·3H 2 O in methanol at room temperature provided the complex [Pd(HL)Cl] ( 1 ) in 82% yield. Treatment of 1 mol equivalent of 1 with 2 mol equivalents of PPh 3 in acetone at room temperature produced the complex [Pd(L)(PPh 3 )] ( 2 ) in 72% yield. The Schiff base and the two complexes were characterized by elemental analysis, mass spectrometric and various spectroscopic (IR, UV–Vis and 1 H NMR) measurements. The molecular structures of both complexes ( 1 and 2 ) were determined by single crystal X-ray crystallography. In each square-planar complex, the tridentate ligand (HL − in 1 and L 2− in 2 ) acts as pincer-like CNO-donor. The fourth coordination site is occupied by chloride in 1 , while that in 2 is satisfied by the P-atom of PPh 3 . The 2-naphthyl fragment of both HL − and L 2− is palladated at the 3-position. Complex 2 was found to be an effective catalyst for one-pot Suzuki-Miyaura double cross-coupling reactions of 3,5-dihalosalicylaldehydes with a variety of arylboronic acids to provide the corresponding triaryl products in moderate to excellent yields. [ABSTRACT FROM AUTHOR]

Abstract: Reactions of [Rh(PPh3)3Cl], [Ir(PPh3)3Cl], Li2[PdCl4] and K2[PtCl4] with the corresponding 4-R-Nʹ-(arylidene)benzohydrazides (H2Ln; n = 1 and 2 for arylidene = 1-pyrenylidene and R = H and Cl, respectively and n = 3 for arylidene = 1-naphthylidene and R = H) in presence of NaOAc·3H2O in methanol/toluene provide the complexes with general formula trans-[Rh(Ln)(PPh3)2H] (1 and 2), trans-[Ir(Ln)(PPh3)2H] (3 and 4), [Pd(HLn)Cl] (5) and [Pt(HLn)Cl] (6), respectively. Reactions of 5 and 6 with PPh3 in acetone produce the complexes [Pd(Ln)(PPh3)] (7) and [Pt(Ln)(PPh3)] (8), respectively. All the complexes have been characterized with the help of microanalysis (CHN), spectroscopic (infrared, NMR, electronic and emission) and cyclic voltammetric measurements. Molecular structures of 1–5 and 8 have been confirmed with single crystal X-ray crystallography. In 5 and 6, (HL1)− acts as a monobasic CNO-donor ligand, whereas in each of 1–4, 7 and 8, the (Ln)2− acts as a dibasic CNO-donor ligand. In 1, 2, 5 and 7, metallation at the peri position of the 1-pyrenyl moiety of the pincer like ligand leads to the formation of 6,5-membered fused chelate rings, whereas in 3, 4, 6 and 8 metallation takes place at ortho position of the 1-pyrenyl/1-naphthalenyl moiety of the ligand with the formation of 5,5-membered fused chelate rings. [Copyright &y& Elsevier]

Abstract: Reactions of Li2PdCl4, 4-R-1-naphthaldehyde benzoylhydrazones (H2L n ; n = 1 and 2 for R = H and OMe, respectively) and NaOAc·3H2O in 1:1:1 mole ratio in methanol provide the cyclopalladated complexes with the general formula [Pd(HL n )Cl] (1 (R = H) and 2 (R = OMe)). Treatment of one mole equivalent of [Pd(HL n )Cl] (1 and 2) with two mole equivalents of PPh3 in acetone results in the deprotonation of the O-coordinated amide functionality and the replacement of the metal coordinated chloride with PPh3 leading to the formation of [Pd(L n )(PPh3)] (3 and 4). All the complexes have been characterized with the help of elemental analysis and spectroscopic (IR, UV–vis and 1H NMR) measurements. NMR spectra indicates the peri-metallation of the 1-naphthalenyl fragment of the tridentate ligand in 1–4. Molecular structures determined by X-ray crystallography confirm the regioselective peri-metallation in each of 2, 3 and 4. [Copyright &y& Elsevier]

Abstract: Reactions of equimolar amounts of Li2PdCl4, 9-anthraldehyde 4-R-benzoylhydrazones (H2L n ; n = 1 and 2 for R = H and NMe2, respectively) and CH3COONa·3H2O in methanol produce the cyclopalladated complexes with the formula [Pd(HL n )Cl] (1 (R = H) and 2 (R = NMe2)). Reactions of [Pd(HL n )Cl] (1 and 2) with 2 mol equivalents of PPh3 in acetone provide the complexes of formula [Pd(L n )(PPh3)] (3 (R = H) and 4 (R = NMe2)). Complexes 1–4 have been characterized by elemental analysis and spectroscopic (IR, UV–vis, fluorescence and NMR) measurements. Molecular structures of 1–4 have been confirmed by X-ray crystallography. In [Pd(HL n )Cl] (1 and 2), the C,N,O-donor (HL n )− and the chloride form a CNOCl square-plane around the metal centre, while (L n )2− and the PPh3 assemble a CNOP square-plane around the metal centre in [Pd(L n )(PPh3)] (3 and 4). [Copyright &y& Elsevier]

Abstract: Reactions of PdCl2, LiCl, indole-3-carboxaldehyde 4-R-benzoylhydrazones (H2L n ; n = 1, 2, 3 and 4 for R = H, Cl, OMe and NMe2, respectively) and CH3COONa·3H2O in 1:2:1:1 mol ratio in methanol produce the cyclopalladated species of general formula [Pd(HL n )Cl] in 65–85% yields. The complexes have been characterized with the help of elemental analysis and spectroscopic (infrared, electronic and NMR) measurements. The proton NMR spectra of the complexes suggest palladation at the peri position of the indole moiety in (HL n )−. Molecular structure of a representative complex determined by X-ray crystallography confirms the peri-palladation and formation of a distorted CNOCl square-plane around the metal centre by the tridentate (HL n )− and the chloride. [Copyright &y& Elsevier]