Gold complexes with potentially tri- and tetradentate phosphinothiolate ligands

Structures and luminescence properties of diethyldithiocarbamate-bridged polynuclear gold(i) cluster complexes with diphosphine/triphosphine

Et₂dtc-linked polynuclear gold(i) complexes modulated structurally through alternation of phosphine ligands exhibit intense solid-state photoluminescence and intriguing thermochromism.

Gold(III) complexes in medicinal chemistry

A number of gold(III) compounds has been designed with the objective of overcoming the disadvantages associated with the platinum-based drugs for cancer treatment. Compounds of a remarkable structural manifold show significant antiproliferative effects in vitro against a number of cancer cells, including cisplatin resistant ones. The target of most of them is, unlike that of cisplatin, not the DNA. Although the mechanisms of action displayed by the gold compounds in biological media are still under investigation, many studies show evidence that the cellular targets are mitochondria-based. Recent advances in gold(III) medicinal chemistry also recommend such compounds for other pharmacological applications such as the treatment of viral or parasitic diseases. The radioactive isotopes 198Au and 199Au present potential in radiotherapy.

Synthesis of Stable Gold(III) Pincer Complexes with Anionic Heteroatom Donors

A series of gold(III) complexes supported by pyridine-based bis(amidate), bis(carboxylate), and bis(iminothiolate) substituents is reported. These compounds represent rare examples of pincer-ligated gold(III) centers with multiple anionic heteroaom donors. Reactivity and electrochemical studies demonstrate the stability of these compounds and the marked difference in reduction potentials with varying ligand scaffolds.

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.

Organometallic molecular materials: self-assembly through hydrogen bonding of an organoplatinum network structure with zeolite-like topology

The complex [Pt(OH)(2)Me(2)(dpa)], dpa = di-2-pyridylamine, undergoes a remarkable form of self-assembly through hydrogen bonding in the solid state; there are cyclic tetramer units formed by head-to-head association between pairs of hydroxyl groups, and cyclic hexamer units formed by head-to-tail association between NH and OH groups; these building blocks then self-assemble to form a complex network structure containing large interconnected cavities, reminiscent of zeolites.

Gold(III) and Platinum(II) Polypyridyl Double Salts and a General Metathesis Route to Metallophilic Interactions

Nine new double-salt compounds have been prepared and six crystal structures are reported that demonstrate a general metathesis route to double-salt compounds with metallophilic interactions. The compounds contain [Pt(terpy)X]+ or [Au(bpy)X2]+ cations, Au(III) or Au(I) anions such as [AuBr4]- or [AuCl2]-, and are prepared in water and recrystallized from organic solvents. In all crystallographically characterized cases, there exist metallophilic interactions between cations and anions, demonstrating the power of this general route. In most cases, there exists an unbroken chain of metallophilic interactions through the crystal, forming single-atom-wide wires.

Tricarbonylrhenium(I) Complexes with Thiosemicarbazone Derivatives of 2-Acetylpyridine and 2-Pyridine Formamide Showing Two Unusual Coordination Modes of Tridentate Thiosemicarbazone Ligands

[NEt(4)](2)[Re(CO)(3)Br(3)] reacts with 2-acetylpyridine phenylthiosemicarbazone (HL(1)) and 2-pyridine formamide thiosemicarbazone (HL(2)) under formation of air-stable, neutral rhenium(I) complexes of the compositions [Re(CO)(3)(L(1)-N,N,S)] and [Re(CO)(3)Br(HL(2)-N,N)]. Spectroscopic studies and X-ray crystallography show that the potentially tridentate thiosemicarbazones adopt unusual coordination modes. Whereas HL(1) deprotonates and binds to the metal in a nonplanar fashion, HL(2) acts as neutral N,N donor ligand. The bond lengths inside the chelate rings are almost uninfluenced by the overall bonding situation.

Group 11 metal complexes of SPS-based pincer ligands: Syntheses, X-ray structures and reactivity

New group 11 d10 (Cu, Au) metal complexes with SPS pincer ligand were synthesized. Insoluble dimeric or oligomeric complexes [(SP(R)S)Cu](n) (R = Bu:4, Me:5) were readily cleaved by several two-electron donor ligands (phosphines, isocyanides, pyridine) to yield a range of new complexes (6-13). X-Ray crystal studies were performed on complexes 7, 8, 9, 11, which revealed distorted tetrahedral geometries and proved once again the flexibility of the SPS ligand, which can accommodate square planar, tetrahedral, octahedral and trigonal bipyramidal geometries. A dimeric gold species with an Au-Au interaction 16 was also synthesized. This dimer could be cleaved with two electron donor ligand (PPh(3):17, RNC: 18). Reactivity of complex 11 with ethyl diazoacetate yielded new lambda5-phosphinine 14.

Stable gold(iii) complexes with thiosemicarbazone derivatives

Novel thiosemicarbazonato complexes of gold(III) have been prepared from reactions of [Au(damp-C1,N)Cl2(damp- = 2-(N,N-dimethylaminomethyl)phenyl) or [NBu4][AuCl4] with 2-pyridineformamide thiosemicarbazones (HL). The thiosemicarbazones deprotonate and coordinate as mononegative, tridentate NNS ligands to gold to give [Au(Hdamp-C1)(L)]Cl2 or [AuCl(L)]Cl complexes. The organometallic damp- ligand is protonated during the reactions and the Au-N bond is cleaved. The [AuCl(L)]+ cations represent the first gold(III) complexes with thiourea derivatives which are not stabilised by an additional organometallic ligand. Reactions of [NBu4][AuX4](X = Cl, Br) with diphenylthiocarbazone (dithizone) result in reduction of the metal and the formation of gold(I) complexes of the composition [AuX(SCN4-3,4-Ph2)] where SCN4-3,4-Ph2 is 3,4-diphenyltetrazole thione which is formed from cyclisation of dithizone.