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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 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]