Synthesis and structural characterization of Pd(II) complexes containing 2,6-bis[(dimethylamino)methyl]-4-methylphenolate ligand

Ghorai, Debasish; Mani, Ganesan

doi:10.1016/j.ica.2011.01.098

Cited by 3 publications

(6 citation statements)

References 22 publications

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“…The geometry around the palladium atom is a distorted square planar in which the phenoxy oxygens or pyrazole nitrogens are trans bonded with the O1–Pd1–N1 and O1 i –Pd1–O1 angles of 92.74(11) and 180.0°, respectively. The N1–Pd1 bond distance of 2.009(3)Å falls within the range of distances reported for complexes containing Pd–N pyrazole bonds , and is shorter than the Pd–N Me2 distance (2.082(5) Å) found in [Pd(OC 6 H 2 (CH 2 NMe 2 ) 2 -2,6-Me-4) 2 ] . The O1–Pd1 bond distance of 2.0004(19) Å is close to those found in palladium complexes containing Pd–O bonds [1.974(11) and 1.989(10)Å, 1.994(4) and 1.987(4) Å], but it is slightly shorter than 2.021(4) Å found in [Pd(OC 6 H 2 (CH 2 NMe 2 ) 2 -2,6-Me-4) 2 ] …”

Section: Resultssupporting

confidence: 72%

“…The structure contains two slightly different Pd–N pyrazole distances: 2.009(4) and 2.020(4) Å; nevertheless, these are very close to the Pd–N distances found in complex 2 and 4 and are in the range reported for other complexes . The Pd–O bond distance of 2.018(3) Å is close to the Pd–O bond in [Pd(OC 6 H 2 (CH 2 NMe 2 ) 2 -2,6-Me-4) 2 ] but is slightly longer than that found in other palladium complexes. , …”

Section: Resultssupporting

confidence: 57%

“…The N1−Pd1 bond distance of 2.009(3)Å falls within the range of distances reported for complexes containing Pd− N pyrazole bonds 24,19 and is shorter than the Pd−N Me2 distance (2.082(5) Å) found in [Pd(OC 6 H 2 (CH 2 NMe 2 ) 2 -2,6-Me-4) 2 ]. 25 The O1−Pd1 bond distance of 2.0004(19) Å is close to those found in palladium complexes containing Pd−O bonds [1.974(11) and 1.989(10)Å, 26 1.994(4) and 1.987(4) Å], 27 but it is slightly shorter than 2.021(4) Å found in [Pd(OC 6 H 2 (CH 2 NMe 2 ) 2 -2,6-Me-4) 2 ]. 25 Complex 3 crystallizes in the noncentrosymmetric orthorhombic space group Aba 2 and the asymmetric unit contains a The twist angle between the palladium square plane and the phenyl ring plane is 46.9°.…”

Section: ■ Introductionmentioning

confidence: 99%

“…25 The O1−Pd1 bond distance of 2.0004(19) Å is close to those found in palladium complexes containing Pd−O bonds [1.974(11) and 1.989(10)Å, 26 1.994(4) and 1.987(4) Å], 27 but it is slightly shorter than 2.021(4) Å found in [Pd(OC 6 H 2 (CH 2 NMe 2 ) 2 -2,6-Me-4) 2 ]. 25 Complex 3 crystallizes in the noncentrosymmetric orthorhombic space group Aba 2 and the asymmetric unit contains a The twist angle between the palladium square plane and the phenyl ring plane is 46.9°. In addition, the angle between the two palladium square planes is 72.8°.…”

Section: ■ Introductionmentioning

confidence: 99%

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Enantiomers and Structural Isomers of Sodium and Palladium Complexes Bearing ortho-Bis(3,5-dimethylpyrazolylmethyl)phenolate: Fluxional Property and Highly Active Catalysts for Norbornene Polymerization

Jana

Mani

2018

Inorg. Chem.

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2,6-Bis(3,5-dimethylpyrazoylmethyl)-4-methylphenol LH was readily synthesized by the reaction between 2,6-bis[(dimethylamino)methyl]-4-methylphenol and 3,5-dimethylpyrazole. The X-ray structure of the trisodium complex of LH showed the benzene-like planar NaO ring with alternative shorter (2.181-2.185 Å) and longer (2.244-2.263 Å) bonds. The reaction of anionic ligand L with [PdCl(COD)] yielded three Pd(II) complexes: [Pd{OCH(CHPz)-2,6-Me-4-κ N, O}] (1), [PdCl{μ-OCH(CHPz)-2,6-Me-4-κ N, O, N}] (2), and [PdCl{μ-OCH(CHPz)-2,6-Me-4-κ N, O, N}Pd] (3) (Pz = 3,5-dimethylpyrazole). Conversely, the neutral ligand LH reacts with [PdCl(PhCN)] to give the 20-membered palladacycle, [PdCl{μ-HOCH(CHPz)-2,6-Me-4-κ N, N}] (4). 2 and 3 are structural isomers and rigid molecules, whereas 1 and 4 are fluxional, as shown by their H NMR spectra. Hence, the dynamic behaviors of 1 and 4 were studied by variable-temperatureH NMR methods and are proposed to be interconversion processes: cis-trans for 1 and two chiral enantiomers for 4. The structures of all complexes were determined by single crystal X-ray diffraction methods, which showed the presence of two different conformations of LH (trans and semitrans) bound to metal atoms. In addition, complexes 2-4 were found to be excellent precatalysts for the vinyl polymerization of norbornene in the presence of varying amount of MMAO and EtAlCl in toluene or CHCl.Within a short period of time (1 min), almost all monomers are changed to polymers with one micromole of precatalyst. The optimized conditions of 1000 molar excess of MMAO gave 1.20 × 10 g PNB mol h at room temperature. These addition polymers are completely insoluble in several organic solvents and hence were only characterized by H, IR, powder XRD, and TGA methods.

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Section: Resultssupporting

confidence: 72%

Section: Resultssupporting

confidence: 57%

Section: ■ Introductionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

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Enantiomers and Structural Isomers of Sodium and Palladium Complexes Bearing ortho-Bis(3,5-dimethylpyrazolylmethyl)phenolate: Fluxional Property and Highly Active Catalysts for Norbornene Polymerization

Jana

Mani

2018

Inorg. Chem.

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“…As a result, the hydrogen bonded chloride atom bond distance Cl2-Pd1 is slightly longer (2.3005(17) Å) than the other Cl1-Pd1 distance (2.2968(15) Å). This is comparable to palladium complexes having this structural feature, which have been reported by us 38 and others. 39 Furthermore, because of this hydrogen bonding the unbound pyrrole-aldehyde moiety is pointed to the other side of the hydrogen bonding so that they form an intermolecular hydrogen bonding with the same groups from an adjacent molecule in the crystal lattice (Fig.…”

Section: Dalton Transactions Papersupporting

confidence: 89%

Exhibition of the Brønsted acid–base character of a Schiff base in palladium(ii) complex formation: lithium complexation, fluxional properties and catalysis of Suzuki reactions in water

Kumar

Mani

2015

Dalton Trans.

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The reaction of the dialdehyde N,N-di(α-formylpyrrolyl-α-methyl)-N-methylamine with two equiv. of 2,6-diisopropylaniline yielded two Schiff bases: bis(iminopyrrolylmethyl)amine () and its hydrolyzed monoimino compound () after column separation. The dimeric lithium complex [(HL)Li]2 () containing the monoanionic form of was obtained by treating with (n)BuLi. The presence of both proton donors and acceptors causes the diimino compound to undergo tautomerization to exhibit an amine-azafulvene structure, though the central amine nitrogen competes for a proton. As a result, in the presence of Pd(2+) ions, the cationic complex [Pd(Cl)(H2L)][Cl] () containing one pendant amine-azafulvene arm and the protonated central amine nitrogen was obtained. Its X-ray structure showed that the bond distances are reversed for the imino-pyrrole moiety relative to those in the structure of . However, the reaction of with [Pd(OAc)2] afforded the neutral complex [PdL] () containing the dianionic form of the ligand. The reaction of with [PdCl2(PhCN)2] yielded a zwitterionic complex [PdCl2(H2L')] () owing to the presence of the central amine nitrogen. The formation of these palladium complexes with the features mentioned above can be explained by invoking the Brønsted acid-base character of the Schiff base. Complex is fluxional owing to the up and down movements of the palladium square plane formed by two 5-membered palladacycles, which causes the interconversion of its enantiomers and is studied by the variable temperature (1)H NMR method. Furthermore, both complexes and are precatalysts for the Suzuki-Miyaura cross-coupling reaction in water. Sterically encumbered and electronically different substrates including activated aryl chlorides and benzyl halides gave the coupled products in very good yields. The reaction proceeds even at room temperature and in the presence of a large excess amount of mercury.

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Synthesis, structure, and conformational mobility of a vaulted trans-bis(o-aminophenolato)platinum(II) complex

Komiya

Takahashi

Tanaka

et al. 2013

Transition Met Chem

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Synthesis and structural characterization of Pd(II) complexes containing 2,6-bis[(dimethylamino)methyl]-4-methylphenolate ligand

Cited by 3 publications

References 22 publications

Enantiomers and Structural Isomers of Sodium and Palladium Complexes Bearing ortho-Bis(3,5-dimethylpyrazolylmethyl)phenolate: Fluxional Property and Highly Active Catalysts for Norbornene Polymerization

Enantiomers and Structural Isomers of Sodium and Palladium Complexes Bearing ortho-Bis(3,5-dimethylpyrazolylmethyl)phenolate: Fluxional Property and Highly Active Catalysts for Norbornene Polymerization

Exhibition of the Brønsted acid–base character of a Schiff base in palladium(ii) complex formation: lithium complexation, fluxional properties and catalysis of Suzuki reactions in water

Synthesis, structure, and conformational mobility of a vaulted trans-bis(o-aminophenolato)platinum(II) complex

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