Synthesis, characterization and catalytic evaluation in the Heck coupling reactions of S–P–S pincer complexes of the type [Pd{PhP(C6H4-2-S)2}(PAr3)]

Monodentate phosphine substitution in [Pd(κ3-dppf)(PR3)][BF4]2 (dppf = 1,1′-bis(diphenylphosphino)ferrocene) compounds

The synthesis and dissociative monodentate phosphine substitution of [Pd(κ³-dppf)(P(p-C₆H₄R)₃)][BF₄]₂ compounds is presented. DFT calculations further examines the nature of the Fe–Pd interaction of the κ³-dppf ligand.

A cyclodiphosphazane based pincer ligand, [2,6-{μ-((t)BuN)2P((t)BuHN)PO}2C6H3I]: Ni(II), Pd(II), Pt(II) and Cu(I) complexes and catalytic studies

Synthesis and late-transition metal complexes of pincer capable cyclodiphosphazane, 2,6-{μ-((t)BuN)2P((t)BuHN)PO}2C6H3I (1) are described. The condensation of 2-iodoresorcinol with cis-{ClP(μ-N(t)Bu)2PN(H)(t)Bu} produced a difunctional derivative 1 in good yield. The treatment of Ni(COD)2, Pd2(dba)3·CHCl3 or Pt(PPh3)4 with 1 afforded pincer complexes [2,6-{μ-((t)BuN)2P((t)BuHN)PO}2C6H3MI] (2 M = Ni; 3 M = Pd and 4 M = Pt). The reaction of complex 3 with copper halides resulted in the formation of heterobimetallic complexes bridged by rhombic {Cu(μ-X)}2 units, [{{Cu(μ-X)}2}{μ-((t)BuN)2P((t)BuHN)PO}2C6H3PdI] (5 X = I and 6 X = Br). The crystal structures of 1-3, and 6 were established by single X-ray diffraction studies. The palladium complex 3 was tested for catalytic P-arylation of diphenylphosphine oxide (Ph2P(O)H) under microwave irradiation. Moderate to good catalytic activity was observed with aryl bromides.

[2-(Diphenylphosphanyl)benzenethiolato-κ2P,S](pyridine-2-thiolato-κS)(triphenylphosphine-κP)palladium(II)

In the title compound, [Pd(C₅H₄NS)(C₁₈H₁₄PS)(C₁₈H₁₅P)], the Pd^II atom has a slightly distorted square-planar environment. Two coordination sites are occupied by a P,S-chelating 2-(diphenyl­phosphan­yl)benzene­thiol­ate ligand and the other two by a P atom from a triphenyl­phosphine ligand and an S atom from a pyridine-2-thiol­ate ligand, exhibiting a trans arrangement of the two P-donor atoms. In the crystal structure, weak intra- and inter­molecular C—H⋯π and π–π inter­actions are observed. The pyridyl ring is equally disordered over two positions.

rac-Carbonyl{1-[(diphenylphosphino)methyl]ethanethiolato}(triphenylphosphine)rhodium(I)

The title compound, [Rh(C₁₅H₁₆PS)(C₁₈H₁₅P)(CO)], was synthesized from the reaction of the ligand rac-[Ph₂PCH₂CH(CH₃)SH] with trans-[Rh(F)(CO)(PPh₃)₂] in a 1:1 molar ratio in toluene. The Rh atom is four-coordinated in a distorted square-planar geometry with the P—S ligand [Ph₂PCH₂CH(CH₃)S] acting as a chelate and the PPh₃ and disordered CO [site occupation factors of 0.61 (5) and 0.39 (5)] ligands completing the coordination.

cis-Bis[2-(diphenylphosphino)benzenethiolato-κ2 P,S]palladium(II)

The title compound, [Pd(C₁₈H₁₄PS)₂], was synthesized by the reaction of (Ph₂PC₆H₄SH) with [PdCl₂(NCC₆H₅)₂] in a 2:1 molar ratio in the presence of a slight excess of NEt₃ as base in dichloro­methane. The compound crystallizes with the Pd(II) atom on a twofold rotation axis. The palladium center has a slightly distorted square-planar environment, with the two P—S chelating ligands adopting a cis configuration. The present structure is a pseudo-polymorph of [Pd(C₁₈H₁₄PS)₂]·CH₂Cl₂.