Synthesis and characterization of η6-p-cymene ruthenium(II) complexes containing alkyl- and methoxy-substituted triarylphosphines

Frustrated and Realized Hydrogen Bonding in 4-Hydroxy-3,5-ditertbutylphenylphosphine Derivatives

“…In the structure of phosphine 3, the Si3 trimethylsiloxy group is positionally disordered (0.83:0.17 ratio) in concert with a placement disorder of a second CHCl 3 solvent molecule that is located just above the C41−C46 aromatic ring (see Figures 2b and S10). The major component of this siloxane is associated with a significant widening of ∠C44−O3−Si3, to 150.72 (15)°, compared to ∠C44−O3A-Si3A, 146.8(1)°, or the ordered sites ∠C24−O2−Si2, 142.6(1)°, and ∠C4−O1− Si1, 141.28(1)°. (The whole of this second CHCl 3 has been omitted in the final refinement with use of a solvent mask as part of the NoSpherA2 refinement strategy; see Experimental Section for details.)…”

“…Recently, the highly lipophilic triarylphosphine A (Chart 1), 14 when employed in an [(η 6 -cymene)RuX 2 PAr 3 ] complex of type B, was shown to have promising behavior for cytotoxic activity in human cancer cell lines (MDA-MB-231 and A549) and little effect against the nontumor cell line MRC-5, which is an indication of possible selective attack on cancerous cells. 15 Encouraged by these results, we decided to synthesize phosphines 2 and 4 (Chart 1), via precursors 1 and 3, with the aim of using the phenol functional groups in the subsequent complexes B as H-bond donors to water, and to create new sites of interaction with the biological environment to enhance chemotherapeutic efficacy while retaining the lipophilicity of the tertbutyl groups in A. Phosphines 1−4 have been previously reported, 16,17 but in the intervening years no applications of them have been reported, and their crystal structures remain unknown. Herein, we report on the syntheses and molecular and supramolecular structures of 1− 4; we also pursued their chalcogenides (P=O, P=S, and P=Se), because under biological conditions any phosphine ligands that might be displaced from their metals are expected to transform rapidly to the oxides; in addition, the selenides are useful to establish phosphine basicity via 1 J P,Se .…”

“…Recently, the highly lipophilic triarylphosphine A (Chart ), when employed in an [(η 6 -cymene)­RuX 2 PAr 3 ] complex of type B , was shown to have promising behavior for cytotoxic activity in human cancer cell lines (MDA-MB-231 and A549) and little effect against the nontumor cell line MRC-5, which is an indication of possible selective attack on cancerous cells . Encouraged by these results, we decided to synthesize phosphines 2 and 4 (Chart ), via precursors 1 and 3 , with the aim of using the phenol functional groups in the subsequent complexes B as H-bond donors to water, and to create new sites of interaction with the biological environment to enhance chemotherapeutic efficacy while retaining the lipophilicity of the tert butyl groups in A .…”

Tuning the Cytotoxicity of Bis-Phosphino-Amines Ruthenium(II) Para-Cymene Complexes for Clinical Development in Breast Cancer

“…Indeed, the expected ABCD spin system for the p-cymene resonances was observed. The IR spectra of Ru1-Ru10 exhibited a broad band around 300 cm −1 for the [46,47], while a strong absorption in the range 1030-1050 cm −1 was attributed to the stretching vibration of the P-C moiety. The UV-Vis absorption spectra of L1-L10 and Ru1-Ru10 were recorded in DMSO solutions (10 −5 M) at 25 • C. L1-L9 presented broad absorption bands centered at 278-290 nm, while L10 presented intense and well-defined characteristic bands of quinoline moieties at 358 nm.…”

“…The absorption spectra of the Ru1-Ru10 compounds featured a very intense band attributed to π−π* electronic transitions corresponding to the Ru-(p-cymene) moiety (λ = 250-304 nm). A weak band is attributable to metal to ligand charge transfer transitions (MLCT) from Ru d orbitals to the π* orbitals of the ligands (304-364 nm), and a shoulder assigned to d−d transitions (364-574 nm) [46].…”