Solution, Structural and Catalytic Studies of Neutral MCl₂ (M = Pd, Pt) Complexes of the N/E Mixed‐Donor Ligands 2‐(RECH₂)C₅H₄N(RE = MeS, PhS, MeSe)

Abstract

The reaction of MCl 2 (M = Pd, Pt) with one mole-equivalent ofconfirmed the complexes to be monomeric with square-planar geometry about the metal centre. Variable-temperature NMR spectroscopy showed that the complexes undergo fluxional processes in solution, which

Supported palladium catalysis using a heteroleptic 2-methylthiomethylpyridine–N,S–donor motif for Mizoroki–Heck and Suzuki–Miyaura coupling, including continuous organic monolith in capillary microscale flow-through mode

“…The solvent was removed in vacuum resulting in a pale orange oil, which was used without further purification (2.75 g, 91%). 1 …”

“…The solvent was removed in vacuum to give a pale brown oil, which was purified by column chromatography [40% EtOAc in hexanes], to give a pale yellow oil (0.75 g, 72%). 1 3.2.5. 4-(4-Hydroxyphenyl)-2-methylthiomethylpyridine (6) Pd(PPh 3 ) 4 (0.397 g, 5 mol %) and 5 (1.50 g, 6.88 mmol) in toluene (28.0 mL) were treated with a degassed solution of Na 2 CO 3 (1.60 g, 13.11 mmol, 2.2 equiv) in H 2 O (14.0 mL), followed by a solution of p-HOC 6 H 4 B(OH) 2 (1.42 g, 10.32 mmol) in MeOH (10.0 mL).…”

“…The product was recrystallised from hot EtOH to give a dark brown solid (1.43 g, 90%). 1 NSO: C,67.50;H,5.66;N,6.06. Found: C,67.54;H,5.62;N,6.11. 3.2.6.…”

“…1). 1 The role of this ligand motif in palladium catalysis has also been explored by Chelucci for addition of diethylzinc to benzaldehyde 2a,b and for allylic substitution, 2a and by Canovese for trimerisation of dimethylacetylene dicarboxylate, 2c and the stoichiometric synthesis of fluoranthenes 2d-f and 2,4-diene-6-ynes. 2f We have recently commenced the development of flow-through capillary 3 and chip 3b based microreactors (100-250 mm internal diameter) employing continuous macroporous organic monolith as support for palladium-catalysed SuzukiMiyaura 3 and Sonogashira 3c reactions.…”

Fluxional interconversion of divalent palladium complexes having NSNSN ligands between flexible SNS and rigid NNN-coordinated structures

“…The negative ΔS° value would be attributable to the flexible structure of 1-SNS, i.e., free rotation of two aromatic ipso carbon-sulfur bonds, S-inversion, and ring inversion of the palladacycles, 30,[49][50][51] whereas the structure of 1-NNN is more rigid and has a lower degree of freedom because these dynamic behaviors are prohibited (Fig. 6).…”