Reactions of palladium dichloride with 4-(trimethylammonio)benzenethiolate and phosphine ligands

Synthesis of platinum, palladium and rhodium complexes of α-aminophosphine ligands

α-Aminophosphine-type ligands are of interest as building blocks of transition metal complexes. This review focuses on the utilization of α-aminophosphines as monodentate and bidentate ligands in platinum, palladium and rhodium complexes. Besides the linear derivatives, the applications of cyclic α-aminophosphines as ligands are also summarized. Various aspects, such as synthesis, structure and applications, as well as the catalytic activity of these complexes are discussed.

Palladium(ii) and palladium(ii)-silver(i) complexes with N-heterocyclic carbene and zwitterionic thiolate mixed ligands: synthesis, structural characterization and catalytic properties

The integration of a geometrically rigid Pd(ii), a coordinatively monotonous N-heterocyclic carbene 1,3-dimethylimidazoline-2-ylidene (IMe), and a flexible zwitterionic thiolate 4-(trimethylammonio)benzenethiolate (Tab) affords a class of Pd-IMe-Tab complexes with various nuclearities, namely, trans-[Pd(IMe)₂(Tab)₂](OTf)₂ (2, mononuclear), cis-[Pd(IMe)₂(Tab)₂](OTf)(Cl) (3a, mononuclear), cis-[Pd(IMe)₂(Tab)₂](PF₆)₂·MeCN (3b·MeCN, mononuclear), [Pd₂(IMe)₄(Tab)₂](PF₆)₄·2MeCN (4·2MeCN, dinuclear) and [Pd₄(IMe)₄(Tab)₆](OTf)₆(Cl)₂ (5, tetranuclear). Further presence of Ag(i) in the assembly provides a heterometallic octanuclear cluster of [Pd₄Ag₄(IMe)₈(Tab)₁₀](PF₆)₁₂ (6). Compounds 2-6 are formed by the reaction of trans-Pd(IMe)₂Cl₂ (1) with various additional reagents via different reaction pathways. These compounds are characterized by means of FT-IR, ¹H and ¹³C NMR, ESI-MS, elemental analysis and X-ray crystallography. Notably, the skeleton of compound 5 features a [Pd₄S₄] parallelogram wherein each of the four Pd(ii) centers bisects the edge defined by the S atoms. The main skeleton of compound 6 is an oval-shaped Pd₄Ag₄S₁₀ unit, featuring an edge-fused norbornane-like (Pd₂Ag₄S₆) framework appended by two additional PdS₂ motifs at the polar positions. Compounds 5 and 6 also feature PdPd (5), PdAg and AgAg (6) interactions. Compound 5 as a representative example is highly effective at catalyzing Suzuki-Miyaura couplings in water, highlighting the potential of applying these types of homo- and heterometallic clusters as catalysts for organic transformations in environmentally benign media.

Synthesis, characterization, photophysical properties, and catalytic activity of an SCS bis(N-heterocyclic thione) (SCS-NHT) Pd pincer complex

Treatment of 1,3-bis(3'-butylimidazolyl-1'-yl)benzene diiodide with elemental sulfur in the presence of a base produced a bis(N-heterocyclic thione) (NHT) pincer ligand precursor. Its reaction with PdCl2(CH3CN)2 produced chloro[1,3-bis(3'-butylimidazole-2'-thione-κ-S)benzene-κ-C]palladium(ii), a 6,6-fused ring SCS-NHT palladium pincer complex. This air stable compound is, to our knowledge, the first SCS pincer complex that utilizes N-heterocyclic thione (NHT) donor groups. The molecular structures of the ligand precursor and the palladium complex were determined by X-ray crystallography and computational studies provided insight into the interconversion between its rac and meso conformations. The photophysical properties of the complex were established, and its catalytic activity in Suzuki, Heck, and Sonogashira cross-coupling reactions was evaluated.

Polydentate chalcogen reagents for the facile preparation of Pd2 and Pd4 complexes

The silylated organochalcogen reagents 1,2-(Me3SiSCH2)2C6H4, and 1,2-(Me3SiSeCH2)2C6H4, were prepared from the corresponding organobromides and lithium trimethylsilanechalcogenolate Li[ESiMe3] (E = S, Se). They have been characterized by multinuclear NMR spectroscopy ((1)H, (13)C, (77)Se) and electrospray ionization mass spectrometry. and react under mild conditions with (1,3-bis(diphenylphosphino)propane)palladium(ii) chloride, [PdCl2(dppp)], to provide the dinuclear organochalcogenolate-bridged complexes [(dppp)2Pd2-μ-κ(2)S-{1,2-(SCH2)2C6H4}]X2, []X2 and [(dppp)2Pd2-μ-κ(2)Se-{1,2-(SeCH2)2C6H4}]X2, []X2 (X = Cl, Br) in good yield, respectively. Furthermore, the tetranuclear palladium complex [(dppp)4Pd4-μ-κ(4)S-{1,2,4,5-(SCH2)4C6H2}]X4, []X4 (X = Cl, Br) can be synthesized from the reaction of the tetrathiotetrasilane 1,2,4,5-(Me3SiSCH2)4C6H2, and [PdCl2(dppp)]. The structures of []X2, []X2 and []X4 were determined by single crystal X-ray diffraction methods. A variety of NMR experiments including two-dimensional homonuclear and heteronuclear correlated spectra were used to probe the solution behaviour of the dinuclear complexes in more detail. These complexes were further characterized by electrospray ionization (ESI) mass spectrometry, and for []X2 and []X2, UV-Vis absorption spectroscopy.

Syntheses and structures of two gold(i) coordination compounds derived from P–S hybrid ligands and their efficient catalytic performance in the photodegradation of nitroaromatics in water

Two Au–P–S complexes [Au₂(dppatc)₂]Cl₂ and [Au(dppmt)]₂ were prepared and they showed high catalytic activity toward the photodegradation of nitroaromatics in water.