‘Click’ generated 1,2,3-triazole based organosulfur/selenium ligands and their Pd(ii) and Ru(ii) complexes: their synthesis, structure and catalytic applications

Abstract

1-(2,6-Diisopropylphenyl)-4-(phenylthio/selenomethyl)-1H-1,2,3-triazole (L1/L2) was synthesized by a 'Click' reaction and treated with [Pd(CH3CN)2Cl2] for 5 h or [(η(6)-C6H6)RuCl(μ-Cl)]2 for 8 h (followed by reaction with NH4PF6) at room temperature, resulting in complexes [Pd(L)Cl2] (1 and 2) or [(η(6)-C6H6)Ru(L)Cl]PF6 (3 and 4) (L = L1 or L2), respectively. The four complexes (1-4) and ligands (L1 and L2) were characterized with (1)H, (13)C{(1)H} and (77)Se{(1)H} NMR spectroscopy and high resolution mass spectrometry. The single crystal structures of 1-4 were solved. The geometry of Pd in 1 and 2 is distorted square planar. The Pd-S and Pd-Se bond distances in 1 and 2 are 2.277(3) and 2.384(6) Å respectively. In 3 and 4, there is a pseudo-octahedral "piano-stool" type disposition of donor atoms around Ru. The Ru-S and Ru-Se bond lengths in 3 and 4 are 2.3728(12) and 2.4741(6) Å respectively. The catalytic activity of complexes 1 and 2 was explored for Suzuki-Miyaura coupling (SMC) in water and the Sonogashira coupling reaction. For various aryl bromides, including deactivated ones, complexes 1 and 2 were found to be efficient catalysts for both couplings. The optimum loading of 1 and 2 required to catalyze both coupling reactions is of the order of 0.001-2 mol% of Pd. For SMC, no additive or phase transfer catalyst was added. For catalysis of the transfer hydrogenation (TH) of aldehydes and ketones, the half-sandwich Ru(ii) complexes 3 and 4 were explored. Their optimum catalytic loading was found to be 0.1-0.4 mol% of Ru. For TH, both the water solvent and the glycerol hydrogen source are environmentally friendly. The catalytic efficiencies of 3 and 4 are comparable with those reported for other catalysts for TH carried out with 2-propanol or glycerol as a H-source. 1, with a sulfur ligand, is more efficient than 2 (Se analog) for both SMC and the Sonogashira coupling. The activities of 3 and 4 for TH are in the order Se > S.

Mixed RuIIComplexes Containing Diseleno‐Ligand and α,β‐Diketones Donors with Anticancer Activity. Synthesis, Characterization, Electrochemical and DFT Studies

“…These are similar and are in the upper range of those that are experimentally known (2.42-2.59 Å). [40][41][42][43][44][45][46] To represent the distortion of octahedron, three parameters are typically used, these indexes are ζ, Σ, and Θ, [64][65][66] and they consider the average distance, sum of angles and the torsions deviations of the bonds respectively, of the metal ion in an ideal octahedral environment (ζ, Σ, Θ = 0). The computational structures present a considerable distortion with deviation values of ζ = 0.9-1.3 Å, Σ = 30-38°and Θ = 120-132°.…”

“…[38,39] The first molecular complexes with RuÀ Se direct bond were reported recently. [40][41][42][43][44][45][46] These compounds show high cytotoxic efficiency [38,42] and have similar or superior inhibitory concentrations than cisplatin (cisPt) drug in the carcinogenic cell lines tested. Additionally, their low toxicity against healthy cells and their ability to produce theragnostic effects, makes them serious candidates to work as anticancer metallodrugs.…”

Copper Catalysis and Organocatalysis Showing the Way: Synthesis of Selenium‐Containing Highly Functionalized 1,2,3‐Triazoles

“…In 2016, Singh and co‐workers synthesized, by a CuAAC reaction, [(phenylselanyl)methyl]‐1,2,3‐triazole 45 and their Pd(II) and Ru(II) complexes, 46 and 47 , respectively. Product 45 was obtained in 85 % yield by the reaction of phenylpropargyl selenide 26a with 2‐azido‐1,3‐diisopropylbenzene 44 in the presence of CuSO 4 .5H 2 O, sodium ascorbate and using a mixture of CH 3 CN/H 2 O (10 : 1) as solvent at 90 °C for 24 h (Scheme ).…”

Iron oxide modified with pyridyl‐triazole ligand for stabilization of gold nanoparticles: An efficient heterogeneous catalyst for A3 coupling reaction in water

“…In recent years ligands such as phosphorus‐ and nitrogen‐based ligands were used for modification and stabilization of Fe 3 O 4 NPs. Very recently, triazoles have been recognized as excellent ligands for metal catalyst stabilization . These highly stable heterocyclic compounds can be produced by the reaction of terminal alkynes with organic azides catalysed by copper (I) complexes …”