Synthesis and structural characterisation of tetrahedral zinc(II) and trigonal bipyramidal cadmium(II) complexes containing N′-cyclohexyl substituted N,N-bispyrazolyl ligand

Choi, Sunghye; Ahn, Seung Hyun; Nayab, Saira; Lee, Hyosun

doi:10.1016/j.ica.2015.07.012

Cited by 12 publications

(1 citation statement)

References 62 publications

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“…As a reference, the starting precursors, i.e ., [CoCl 2 ], [ZnCl 2 ], [CuCl 2 ], or MMAO alone were also tested for MMA polymerization at a specific temperature. The catalytic activity of complexes in the current study was more active compared with our previously reported complexes . Specifically, the activity of [Co(nmpc)Cl 2 ] (7.45 × 10 4 g PMMA/mol Co · h) and [Zn(nmpc)Cl 2 ] (3.08 × 10 4 g PMMA/mol Zn · h) increased almost twofold compared with [CoCl 2 ] (4.03 × 10 4 g PMMA/mol Co · h) and [ZnCl 2 ] (1.73 × 10 4 g PMMA/mol Zn · h) at 60 °C, respectively (Table 1).…”

Section: Methodscontrasting

confidence: 43%

Polymerization of Methyl Methacrylate Catalyzed by Co(II), Cu(II), and Zn(II) Complexes Bearing N‐Methyl‐N‐((pyridin‐2‐yl)methyl)cyclohexanamine

Ahn

Shin

Nayab

et al. 2016

Bulletin Korean Chem Soc

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Transition metal complexes containing N,N 0 -bidentate pyridylmethylamines ligands continue to receive attention since these ligands can be synthesized with high coordination versatility by introducing various substituents on the amine and/or pyridyl unit. [1][2][3][4][5] Several structural variations in pyridylmethylamines and their complexes have been reported, [6][7][8] and the resultant steric and electronic properties are important for specific chemical applications. The majority of transition metal complexes bearing these ligands have been used in a number of investigations including synthetic, structural analysis and spectroscopic applications, 9-12 as well as for electronic materials, 4,5 catalysts for organic transformation, 13-15 biological applications, 16 and olefin polymerization. 17,18 In contrast, poly(methyl methacrylate) (PMMA) is a universal polymer with optical applications, and its improved optical properties are dependent on the higher glass transition temperature (T g ) and syndiotacticity of PMMA. Radical-mediated polymerization of methyl methacrylate (MMA) cannot achieve sufficiently high T g or a high syndiotacticity in PMMA. Thus, non-radicalmediated MMA polymerization that can result in a higher T g up to 140C is an active and promising field of research.19-22 Recently, we have explored various transition metal complexes as catalysts for homogeneous polymerization of MMA to produce syndiotactic PMMA with high T g up to 130C. 23,24 Considering the versatility of the pyridylbased ancillary ligands and their ability to fine-tune steric and electronic properties, we extended our investigations to the synthesis of novel Co(II), Cu(II), and Zn(II) complexes supported by specific N-methyl-N-((pyridin-2-yl)methyl) cyclohexanamine (nmpc), which shows unique activity and selectivity with several transition metals during MMA polymerization.The complexation reactions proceeded smoothly at room temperature by treating with EtOH solution of (nmpc) with stoichiometric amounts of metal starting material and afforded [M(nmpc)Cl 2 ] n (M = Co and Zn, n = 1; M = Cu, n = 2) in high yields (91-96%) (Scheme 1). The results of 1 H NMR, 13C NMR, IR, and elemental analysis were consistent with the ligands and corresponding complex formation. Particularly, the 1 H NMR spectra of Zn(II) confirmed complexation of the respective ligand; as expected, the majority of the ligand proton signals were observed at a lower field for the complexes relative to the corresponding free ligand. In addition, the incorporation of Me substituents on the N atoms of the ligand architecture resulted in enhanced solubility of corresponding complexes in organic solvents.X-ray diffraction analysis revealed that [Co(nmpc)Cl 2 ] and [Zn(nmpc)Cl 2 ] crystallized in the monoclinic system with space group P2 1 /c and existed as monomeric and solvent-free complexes. [Cu(nmpc)(μ-Cl)Cl] 2 existed as a dimer with space group P-1. The structures for [Co(nmpc)Cl 2 ], [Zn (nmpc)Cl 2 ], and [Cu(nmpc)(μ-Cl)Cl] 2 at a 50% probability level, along with ...

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Section: Methodscontrasting

confidence: 43%

Polymerization of Methyl Methacrylate Catalyzed by Co(II), Cu(II), and Zn(II) Complexes Bearing N‐Methyl‐N‐((pyridin‐2‐yl)methyl)cyclohexanamine

Ahn

Shin

Nayab

et al. 2016

Bulletin Korean Chem Soc

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Synthesis of N,N′,X‐tridentate 2‐iminomethylpyrrole‐coordinated palladium(II) complexes via N─H bond activation of pyrrole moiety

Kim

Seo

Nayab

et al. 2017

Applied Organom Chemis

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The reaction of [Pd(CH3CN)2Cl2] with N‐functional group‐substituted 2‐iminomethylpyrrole‐based ligands, namely N1‐((1H‐pyrrol‐2‐yl)methylene)‐N3,N3‐dimethylpropane‐1,3‐diamine (LA), N1‐((1H‐pyrrol‐2‐yl)methylene)‐N3‐methyl‐N3‐phenylpropane‐1,3‐diamine (LB), N‐((1H‐pyrrol‐2‐yl)methylene)‐3‐(methylthio)propan‐1‐amine (LC) and N‐((1H‐pyrrol‐2‐yl)methylene)‐3‐methoxypropan‐1‐amine (LD), resulted in [LnPdCl] (Ln = LA–LD) complexes in high yield via N─H bond activation of pyrrole moiety without use of base. [LnPdCl] existed as monomeric four‐coordinated complexes with slightly distorted square planar geometries around the palladium metal center. The ligands show N,N′,X‐tridentate binding mode to the palladium metal center to give two fused ring metallacycles. [LBPdCl] gave the highest activity (3.29 × 105 g PMMA (mol Pd)−1 h−1) for a methyl methacrylate (MMA) polymerization in the presence of modified methylaluminoxane at 60 °C compared to the other Pd(II) analogues, and resulted in PMMA with higher molecular weight (Mw = 7.16 × 105 g mol−1) and narrower polydispersity index. Syndiotactic‐enriched PMMA resulted in all cases.

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Synthesis, structures and reactivity of cobalt(II) complexes supported by N,N,N′,N″-tetradentate N′-substituted bis((1H-pyrazol-1-yl)methyl)amine

Seo

Lee

Kim

et al. 2019

Inorganica Chimica Acta

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Synthesis and structural characterisation of tetrahedral zinc(II) and trigonal bipyramidal cadmium(II) complexes containing N′-cyclohexyl substituted N,N-bispyrazolyl ligand

Cited by 12 publications

References 62 publications

Polymerization of Methyl Methacrylate Catalyzed by Co(II), Cu(II), and Zn(II) Complexes Bearing N‐Methyl‐N‐((pyridin‐2‐yl)methyl)cyclohexanamine

Polymerization of Methyl Methacrylate Catalyzed by Co(II), Cu(II), and Zn(II) Complexes Bearing N‐Methyl‐N‐((pyridin‐2‐yl)methyl)cyclohexanamine

Synthesis of N,N′,X‐tridentate 2‐iminomethylpyrrole‐coordinated palladium(II) complexes via N─H bond activation of pyrrole moiety

Synthesis, structures and reactivity of cobalt(II) complexes supported by N,N,N′,N″-tetradentate N′-substituted bis((1H-pyrazol-1-yl)methyl)amine

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