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Trans-di(ortho-tolylethynyl)bis(dimethylphenylphosphine)palladium(II) reacts above −20 °C with the iodonium reagent IPhCl2 to give predominantly o-Tol–C≡Cl, above 15 °C with IPh2(OTf) (OTf = triflate) to give o-Tol–C–Ph and (o-Tol–C≡C)2 in ca. 3:1 ratio, and above 10 °C with IPh(C≡CR)(OTf)(R = But, SiMe3) to give predominantly o-Tol–C≡C–C≡C–R and (o-Tol–C≡C)2. 31P NMR spectra provide evidence for detection of intermediates. The complexes trans-[Pd(C≡C-o-Tol)2(PMe2Ph)2] and trans-[PdCl(C≡C-o-Tol)(PMe2Ph)2] are obtained on reaction of trans-[PdCl2(PMe2Ph)2] with Li(C≡C-o-Tol) and o-Tol-C≡C/Et3N, respectively, and have been characterised by X-ray crystallography. [ABSTRACT FROM AUTHOR]

Abstract: Flow-through catalysis utilising (2-methylthiomethylpyridine)palladium(II) chloride species covalently attached to a macroporous continuous organic polymer monolith synthesised within fused silica capillaries of internal diameter 250μm is described, together with related studies of ground bulk monolith compared with supported catalysis on Merrifield and Wang beads and homogeneous catalysis under identical conditions to bulk supported catalysis. The monolith substrate, poly(chloromethylstyrene-co-divinylbenzene), has a backbone directly related to Merrifield and Wang resins. The homogeneous precatalyst PdCl2(L2) (L2=4-(4-benzyloxyphenyl)-2-methylthiomethylpyridine) contains the benzyloxyphenyl group on its periphery as a model for the spacer between the ‘PdCl2(N∼S)’ centre and the polymer substituent of the resins and monolith. Suzuki–Miyaura and Mizoroki–Heck catalysis exhibit anticipated trends in reactivity with variation of aryl halide reagents for each system, and show that supported catalysis on beads and monolith gives higher yields than for homogeneous catalysis. The synthesis of 2-methylthiomethylpyridines is presented, together with crystal structures of 4-bromo-2-bromomethylpyridine hydrobromide, 4-(4-hydroxyphenyl)-2-methylthiomethylpyridine (L1), PdCl2(L1) and PdCl2(L2). Hydrogen bonding occurs in 4-bromo-2-bromomethylpyridine hydrobromide as N–H⋯Br interactions, in 4-(4-hydroxyphenyl)-2-methylthiomethylpyridine as O–H⋯N to form chains, and in PdCl2(L1) as O–H⋯Cl interactions leading to adjacent π-stacked chains oriented in an antiparallel fashion. [Copyright &y& Elsevier]

Abstract: A solid macroporous monolith is shown to be a suitable substrate for anchoring a palladium complex to obtain a continuous porous material suitable for conducting flow-through catalysis in capillary microreactors. [Copyright &y& Elsevier]

Synthetic routes to neopentyl and trimethylsilylmethyl complexes of Pd(II) are reported, Pd(CH2EMe3)Ph(tmeda) [E=C (1), Si (3); tmeda=N,N,N′,N′-tetramethylethylenediamine] and Pd(CH2EMe3)Ph(bpy) [E=C (2), Si (4); bpy=2,2′-bipyridine]. Complexes 1 and 3 are formed on the reaction of PdIPh(tmeda) with LiCH2EMe3, and they react with bpy to give 2 and 4. Oxidative addition reactions of 8-(bromomethyl)quinoline (mqBr) with Pd(CH2EMe3)Ph(bpy) result in the formation of octahedral Pd(IV) complexes [Pd(mq)(CH2EMe3)Ph(bpy)]Br [E=C (5), Si (6)]. An X-ray structural analysis for 5, the first example of a stable cationic arylpalladium(IV) complex, shows a fac-PdC3N3 configuration with the neopentyl group trans to the quinoline nitrogen donor atom. [Copyright &y& Elsevier]

The reaction of phenyl(alkynyl)iodine(III) triflates with diorganoplatinum(II) complexes provides a general route for the synthesis of a new class of alkynylplatinum(IV) complexes containing PtIVR2(C&z.tbnd6;CR2) groups, e.g., the 4,4′-bis(tert-butyl)-2,2′-bipyridine complexes PtIR2(C&z.tbnd6;CSiMe3)(But2bpy) (R=Me, Ph); IPh2(OTf) reacts with PtPh2(But2bpy) to form the first archetypal triarylplatinum(IV) complex PtIPh3(But2bpy). [Copyright &y& Elsevier]

Abstract: The development and advantages of in situ synthesis of organic polymer monolith supports for metal pre-catalysts in narrow bore fused silica capillary microreactors are described. Catalyst immobilisation involves the covalent attachment of ligand binding sites to the porous polymer monolith, followed by coordination to metal centres. Flow-through microreactors using poly(chloromethylstyrene-co-divinylbenzene) monolith in capillaries of internal diameter 250μm were used successfully for Suzuki–Miyaura and Sonogashira reactions, utilising both 1,10-phenanthroline and imidazole/carbene binding to palladium and with very low palladium leaching, illustrating the potential of flow-through technology at the microscale level using organic monolith support for transition metal catalysed reactions. [Copyright &y& Elsevier]

Abstract: A convenient synthetic method for the preparation of organothiomethylpyridine ligands 2-(RSCH2)C5H4N (R=Ph (L 1), Me (L 2)), 2-MeS–6-Me-C5H3N (L 3), and 2-MeS–4-Me-C5H3N (L 4) via the initial lithiation of substituted 2-picolines followed by the nucleophilic reaction with a diorganyldisulfide is described. The complexes [PtBr2L] (L= L 1–L 4) have been prepared in good to high yields as yellow solids with low solubility in organic solvents. The solid state structures of the complexes have been determined, showing the spatial arrangement of the complexes to depend significantly upon varying substituents within the ligand. The complexes undergo oxidation by bromine to form the tetravalent complexes [PtBr4(L)] (L= L 1–L 4). The solid state structures of [PtBr4(L 2)] and [PtBr4(L 4)] have been determined, and shown to be monomeric with the ligand chelating the platinum centre. [Copyright &y& Elsevier]