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A new imine ligand avoiding imine-enamine rearrangement and cyclometallation: Synthesis and coordination of Me3C6H2CH2N:CHtBu
The new imine ligand (E)-2,4,6-Me3C6H2CH2N:CHtBu (1) has been prepd. from 2,4,6-trimethylbenzylamine and trimethylacetaldehyde. In this imine, the ortho-positions of the benzyl group are blocked by Me groups, and there are no ?-hydrogen atoms susceptible for imine-enamine rearrangement. Thus, reaction with [PdCl2(C6H5CN)2] leads to the complex trans-[PdCl2(2,4,6-Me3C6H2CH2N:CHtBu)2] (2) that cannot undergo cyclopalladation. The single-crystal x-ray structure anal. of trans-[PdCl2(2,4,6-Me3C6H2CH2N:CHtBu)2] (2) confirms the trans-coordination of the imine ligands in this square-planar complex. [on SciFinder(R)]
(±)-Di-μ-chlorido-(μ-N,N'-{[3,3'-methylenebis(2,4,6-trimethyl-3,1-phenylene)]dimethylene}bis(2-methylpropan-2-amine))bis[chloridopalladium(II)]
In the title dinuclear palladium complex, [Pd2Cl4 (C29H46N2)], the terminal ligands adopt an anti configuration, with an intramolecular metal-metal distance of 3.3625 (5) Å. The dinuclear palladium complex adopts a V-shaped conformation, with a dihedral angle of 152.67 (3)° between the two chloride-bridged PdNCl3 square-planar systems. The benzene rings in the chelating amine ligand are at an angle of 74.9 (1)° with respect to each other. The complex is the first example of chloride-bridged dinuclear palladium complex with a bidentate secondary amine ligand.
A new imine ligand avoiding imine–enamine rearrangement and cyclometallation: Synthesis and coordination of Me3C6H2CH2NCHtBu
The new imine ligand (E)-2,4,6- Me3C6H2CH2NCHtBu (1) has been prepared from 2,4,6-trimethylbenzylamine and trimethylacetaldehyde. In this imine, the ortho-positions of the benzyl group are blocked by methyl groups, and there are no β-hydrogen atoms susceptible for imine–enamine rearrangement. Thus, reaction with [PdCl2 (C6H5CN)2] leads to the complex trans-[PdCl2 (2,4,6- Me3C6H2CH2NCHtBu)2] (2) that cannot undergo cyclopalladation. The single-crystal X-ray structure analysis of trans-[PdCl2 (2,4,6- Me3C6H2CH2NCHtBu)2] (2) confirms the trans-coordination of the imine ligands in this square-planar complex.
Square-planar dichloro palladium complexes with trans-configurated phosphine ligands avoiding ortho-metallation: Ligand design, complex synthesis, molecular structure and catalytic potential for Suzuki cross-coupling reactions
The square-planar palladium complexes trans-[PdCl2 (PPh2-CH2-2,4,6-C6H2Me3)2] (1) and trans-[PdCl2 (η2-PPh2-CH2-2,4,6-C6HMe3-CH2-2,4,6-C6HMe3-CH2-PPh2)] (2) have been synthesized from [PdCl2 (cod)] (cod = 1,5-cyclooctadiene) and the corresponding new phosphine or diphosphine ligands. The single-crystal X-ray structure analysis reveals for both complexes a trans arrangement of the two chlorine and of the two phosphorus atoms. In both cases, ortho-metallation leading to palladacycles is not possible, since all ortho positions in the benzylic rings of 1 and 2 are blocked by methyl substituents. Both complexes are found to catalyze Suzuki cross-coupling reactions of deactivated and even bulky arene substrates.
Square-planar diacetatopalladium complexes with trans-configured secondary amine ligands that avoid orthometalation: ligand synthesis, coordination, molecular structure and catalytic potential for Suzuki cross-coupling reactions
The trans-configured square-planar palladium complexes [Pd(OAc)2(LNtBu)2] (1), [Pd(OAc)2(?2-LN?NtBu)] (2), [Pd(OAc)2(LNPh)2] (3), and [Pd(OAc)2(?2-LN?NPh)] (4), were synthesized by treating palladium acetate with the amines NHtBuCH2-2,4,6-Me3C6H2 (LNtBu) or NHPhCH2-2,4,6-Me3C6H2 (LNPh) or with the diamines NHtBuCH2-2,4,6-Me3C6H-CH2-2,4,6-Me3C6H-CH2-NHtBu (LN?NtBu) or NHPh-CH2-2,4,6-Me3C6H-CH2-2,4,6-Me3C6H-CH2-NHPh (LN?NPh). The single-crystal x-ray structure anal. of complexes 1-3 confirms a trans arrangement of the two acetato groups and of the two nitrogen atoms. Orthometalation leading to palladacycles is impossible in all cases as the ortho positions in the benzylic rings are blocked by Me substituents. All complexes are found to catalyze Suzuki cross-coupling reactions of deactivated and even sterically hindered arene substrates. [on SciFinder(R)]
Di-μ-diphenylphosphido-bis{chlorido[(mesitylmethyl)diphenylphosphine-κP]palladium(II)}
In the title dinuclear palladium complex, [Pd2 (C12H10P)2Cl2 (C22H23P)2], the terminal ligands adopt a trans configuration with a Pd•••Pd distance of 3.6111 (4) Å. A crystallographic twofold rotation axis runs perpendicular to the Pd2P2 ring. The Cl atom lies slightly out of the plane of the Pd and three P atoms in each half of the molecule.
trans-Dichloro{P,P'-[3,3'-oxybis(m-phenylenemethylene)]bis(diphenylphosphine)}palladium(II)
Crystals of the title compd. are orthorhombic, space group Pbca; Z = 8. The square-planar complex shows the P atoms to be trans coordinated, with a P-Pd-P angle of 176.50(4)°. The Ph rings in the P ligand are inclined at an angle of 61.2(1)° to each other. [on SciFinder(R)]
Di-?-diphenylphosphido-bis{chlorido[(mesitylmethyl)diphenylphosphine-?P]palladium(II)}
In the title dinuclear palladium complex, [Pd2(C12H10P)2Cl2(C22H23P)2], the terminal ligands adopt a trans configuration with a Pd···Pd distance of 3.6111(4) Å. A crystallog. twofold rotation axis runs perpendicular to the Pd2P2 ring. The Cl atom lies slightly out of the plane of the Pd and three P atoms in each half of the mol. [on SciFinder(R)]
Square-Planar Diacetatopalladium Complexes with trans-Configured Secondary Amine Ligands that Avoid Orthometalation: Ligand Synthesis, Coordination, Molecular Structure and Catalytic Potential for Suzuki Cross-Coupling Reactions
The trans-configured square-planar palladium complexes [Pd(OAc)2 (LNtBu)2] (1), [Pd(OAc)2 (η2-LN∩NtBu)] (2), [Pd(OAc)2 (LNPh)2] (3), and [Pd(OAc)2 (η2-LN∩NPh)] (4), have been synthesized by treating palladium acetate with the amines NHtBuCH2-2,4,6-Me3C6H2 (LNtBu) or NHPhCH2-2,4,6-Me3C6H2 (LNPh) or with the diamines NHtBuCH2-2,4,6-Me3C6H-CH2-2,4,6-Me3C6H-CH2-NHtBu (LN∩NtBu) or NHPh-CH2-2,4,6-Me3C6H-CH2-2,4,6-Me3C6H-CH2-NHPh (LN∩NPh). The single-crystal X-ray structure analysis of complexes 1-3 confirms a trans arrangement of the two acetato groups and of the two nitrogen atoms. Orthometalation leading to palladacycles is impossible in all cases as the ortho positions in the benzylic rings are blocked by methyl substituents. All complexes are found to catalyze Suzuki cross-coupling reactions of deactivated and even sterically hindered arene substrates.
Square-planar dichloro palladium complexes with trans-configurated phosphine ligands avoiding ortho-metallation: Ligand design, complex synthesis, molecular structure and catalytic potential for Suzuki cross-coupling reactions
The square-planar palladium complexes trans-[PdCl2(PPh2-CH2-2,4,6-C6H2Me3)2] (1) and trans-[PdCl2(?2-PPh2-CH2-2,4,6-C6HMe3-CH2-2,4,6-C6HMe3-CH2-PPh2)] (2) were synthesized from [PdCl2(cod)] (cod = 1,5-cyclooctadiene) and the corresponding new phosphine or diphosphine ligands. The single-crystal x-ray structure anal. reveals for both complexes a trans arrangement of the two chlorine and of the two phosphorus atoms. In both cases, ortho-metalation leading to palladacycles is not possible, since all ortho positions in the benzylic rings of 1 and 2 are blocked by Me substituents. Both complexes catalyze Suzuki cross-coupling reactions of deactivated and even bulky arene substrates. [on SciFinder(R)]