Heteropolynuclear Gold Complexes with Metallophilic Interactions: Modulation of the Luminescent Properties

Abstract

Metalloligands of stoichiometry [AuCl(P−N)] have been obtained by the reaction of the heterofunctional phosphines P−N = PPh2py, PPh2CH2CH2py, or PPhpy2 with [AuCl(tht)] (tht = tetrahydrothiophene). Reactions of these metalloligands with several metal compounds have afforded heteropolynuclear species which exhibit luminescent properties. The stoichiometries depend on the molar ratio and the heterometal. Thus, the reaction with [Cu(NCMe)4]+ in a molar ratio 2:1 gives the trinuclear compounds [Au2CuCl2(P−N)2]+, in which the structure and Au···Cu interactions depend on the phosphine ligand. With rhodium and iridium derivatives the reactivity is different leading to complexes of the type [AuMCl2(cod)(P−N)] for P−N = PPh2py, PPhpy2, and [Au2M2Cl(cod)2(P−N)2]Cl with PPh2CH2CH2py. Using [MCl2(NCPh)2] (M = Pd, Pt) in a 2:1 molar ratio yields [Au2MCl4(P−N)2] and in a 1:1 molar ratio [AuPdCl3(μ3-PPhpy2)]. Several compounds have been characterized by X-ray diffraction showing in many cases short Au···M distances. The luminescence of these derivatives has been studied. The metalloligands display bands assigned to intraligand (IL) transitions. For the bimetallic (Au/M) systems the luminescence depends on the heterometal present and on the metallophilic interactions. The most important excitations in the relevant energy range were assigned essentially a MMLCT character (from Rh/Ir and Au to ligands) based on density functional theory (DFT) calculations in selected complexes. The luminescence behavior in Rh/Ir [AuMCl2(cod)(PPh2py)] complexes was interpreted on the basis of the different nature of the half occupied orbitals in the triplet state.

Impedance technology reveals correlations between cytotoxicity and lipophilicity of mono and bimetallic phosphine complexes

“…Further investigation by NMR and X-ray spectroscopy of the reaction mixture of the supposed instable second bimetal (2a) confirmed the presence of traces of 2b, Au 2 Pd(L2) 2 Cl 4 , in solution (Scheme 1), also previously synthesised by Calhorda et al (Calhorda et al, 2010), hence no spectral data is presented. This complex unlike 1a and the proposed 2a structure is structurally bulkier containing two Au atoms, each independently linked to L2 and bridged by a Pd atom coordinated to the nitrogen atom of the pyridine ring of both L2 moieties.…”

“…(2) were prepared using the method by Calhorda and colleagues (Calhorda et al, 2010) and hence there is no need for discussion of the spectral data. …”

“…Compounds 1 (Alcock et al, 1982) and 2 (Calhorda et al, 2010) have previously been synthesised but in this study both compounds were done by a slightly modified method that led to better yields; whilst compound 1a which was prepared by adopting a one-pot approach is novel. All complexes were synthesized in good to excellent yields.…”

The Coordination and Supramolecular Chemistry of Gold Metalloligands

“…The heterometallic complexes of 13 and 15 show short M···Au interactions, supported by the (2-pyridyl)phoshine ligands, as illustrated by complexes 19-21. [26] An analogue of 19,c ontaining a3 ,5-dichloro-2,4,6-trifluorophenyl group instead of the chloro group, hasbeen similarly prepared by López-de-Luzuriaga, Catalano, and co-workers. [27] Laguna, Eisenberg, and coworkers reported the self-assemblyo ft etranuclear complexes of the type 22 when 13 was treated with Ag 2 Oa nd NaBF 4 (E = O), or with [Au 2 (m-E)(PPh 2 py) 2 ]a nd AgBF 4 (E = S, Se).…”

Fourier Transform Infrared spectroscopy discloses different types of cell death in flow cytometrically sorted cells

“…biphenylgold(I) chloride (AE125) were synthesized (Alcock et al, 1982;Calhorda et al, 2010) and characterized by Elkhadir (2014) (Elkhadir, 2014) under the supervision of Prof.…”