β-Hydroxydithiozimtsäurederivate als Liganden. Synthese und Charakterisierung neuartiger 1,1-Ethendithiolato- und O,S-Chelatkomplexe / Derivatives of β -Hydroxydithiocinnamic Acids as Ligands. Syntheses and Characterisation of Novel 1,1-Ethenedithiolato and O,S-Chelate Complexes

Abstract

Starting from 4-bromoacetophenone 1, the 4-bromo-β -hydroxydithiocinnamic acid 2 and the 4-bromo-β -hydroxydithiocinnamic acid hexyl ester 3 were prepared using carbon disulfide and potassium-tert-butylate as a base. Acting as a ligand, the acid gives 1,1-ethenedithiolato complexes with (Ph3P)2Pt(II) (4a), (Et3P)2Pt(II) (4b), dppePt(II) (4c), (Ph3P)2Pd(II) (4d), dppePd(II) (4e), and dppeNi(II) (4f). In contrast to the acid, the deprotonated ester 3 forms a monoanionic bidentate ligand. [O,S] Complexes of Pt(II) (5a), Pd(II) (5b) and Ni(II) (5c) were obtained. All complexes have been fully characterised using 1H NMR, 13C NMR and 31P NMR spectroscopy, mass spectrometry, infrared spectroscopy and elemental analyses. The molecular structures of the complexes 4b and 5a - 5c were determined by X-ray diffraction analyses.

Platinum(ii) O,S complexes as potential metallodrugs against Cisplatin resistance

“…Ligands L1-L12 can be found in the literature, but their cytotoxic effects have not been determined until now. [33][34][35][36][37][38][39] Platinum(II) complexes Pt7-Pt12 have been reported earlier, and this work presents the biological significance of these compounds depending on their antitumor activity for the first time and reinvestigates what has been reported earlier. 33,40…”

“…Cinnamic acid derivatives L1-L12 were synthesized according to the modified literature methods. 34,[37][38][39] A general pathway is shown in Scheme 1. For the synthesis of the platinum(II) complexes (Scheme 2) two pathways differing in the amount of t-BuOK can be applied.…”

Novel Homoleptic and Heteroleptic Pt(II) β‐oxodithiocinnamic ester Complexes: Synthesis, Characterization, Interactions with 9‐methylguanine and Antiproliferative Activity

“…All compounds were characterized by NMR spectroscopy, mass spectrometry and elemental analysis. The chemical shifts in 1 H NMR and 13 C{1H} NMR spectra for ligands HL1‐HL9 are generally in good agreement with previously reported values [8–17,35–39] . In the 1 H NMR spectra, HL1‐HL9 display a single resonance signal in the range of δ 14.49–15.17 ppm belonging to the hydroxyl group (−OH) proton, which is not observed in the complexes [Pt(L1–L9) 2 ], [Pt(L1–L9)(DMS)Cl], and [Pt(L1–L9)(DMSO)Cl].…”

“…The chemical shifts in 1 H NMR and 13 C{1H} NMR spectra for ligands HL1-HL9 are generally in good agreement with previously reported values. [8][9][10][11][12][13][14][15][16][17][35][36][37][38][39] In the 1 H NMR spectra, HL1-HL9 display a single resonance signal in the range of δ 14.49-15.17 ppm belonging to the hydroxyl group (À OH) proton, which is not observed in the complexes [Pt(L1-L9) 2 ], [Pt(L1-L9)(DMS)Cl], and [Pt(L1-L9)(DMSO)Cl]. The methine proton (=CHÀ ) found at δ 6.66-7.44 ppm and δ 6.76-7.32 ppm for the ligands and complexes, respectively, is virtually unchanged.…”

“…Compared to the free DMSO, there is observed a downfield shift by 1.1 and 6 ppm in both 1 H and 13 C{1H} NMR spectra, respectively, which also confirm the formation of a mono-chelate complex with Scoordinated DMSO ligand which is in accordance with previously described Pt-DMSO complexes. [13][14][15][16][35][36][37][38][39][42][43][44][45][46] 195 Pt NMR spectra for the bis-chelate complexes [Pt(L1-L9) 2 ] as well as the mono-chelate complexes [Pt(L1-L9)(DMS)Cl] and [Pt(L1-L9)(DMSO)Cl] were obtained. The signals appeared in the range of (À 2267 to À 2350 ppm) and (À 2879 to À 3079 ppm), for the bis-chelate and mono-chelate complexes, respectively, which is in good agreement with the previously reported values.…”