Coordination behaviour of symmetrical hexadentate N-donor Schiff bases towards zinc(II)pseudohalides: Syntheses, crystal structures and luminescence

Ghosh, Rajarshi; Rahaman, Sk Hafijur; Lin, Chun‐Nan; Lu, Tian‐Huey; Ghosh, Barindra Kumar

doi:10.1016/j.poly.2006.05.037

Cited by 59 publications

(21 citation statements)

References 38 publications

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“…[9][10][11] Many * For correspondence thin films of metal complexes, such as Zn(II), Pt(II), Cu(II) or Ag(I) with Schiff bases (e.g., N,N -bis(salicyli dene)-1,2-ethylenediamine, bis(2-(2-hydroxyphenyl) benzothiazole) were synthetised and their luminescence properties have been employed in organic optoelectronics. [12][13][14][15] The thin organic-inorganic layers of different metal compounds were obtained by many different methods e.g., laser ablation, cathodoluminescence or spin coating. [16][17][18][19] However, there are only a few reports on copper(II) complexes in materials obtained by spin coating method.…”

Section: Introductionmentioning

confidence: 99%

Copper(II) Schiff base complexes and their mixed thin layers with ZnO nanoparticles

2016

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Cu(II) complexes with Schiff bases derived from ethylenediamine (en) and 2-pyridinecarboxaldehyde (pyca), 2,5-dimethoxybenzaldehyde (dmbaH) or 4-imidazolecarboxaldehyde (4Him) were obtained and studied by elemental analysis, UV-VIS and IR spectra. Zinc oxide was synthesized using a simple homogeneous precipitation method with zinc acetate as a starting material. Thin layers of the studied Cu(II) complexes were deposited on Si(111) or ZnO/Si(111) substrates by a spin coating method and characterized with a scanning electron microscopy (SEM/EDS), atomic force microscopy (AFM) and fluorescence spectroscopy. For Cu(II) layers the most intensive fluorescence bands due to intra-ligand transitions were observed between 462 and 503 nm. The fluorescence intensity of thin layers was corelated to the rotation speed. In the case of the [Cu(II)(en(4Him) 2 )Cl 2 ](2a)/ZnO/Si and [Cu(en(dmbaH) 2 )Cl 2 ](3a)/ZnO/Si layers the quenching of the emission band from ZnO at 440 nm (λ ex = 330 nm) associated with various intrinsic or extrinsic lattice defects was noted.

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Section: Introductionmentioning

confidence: 99%

Copper(II) Schiff base complexes and their mixed thin layers with ZnO nanoparticles

2016

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“…Schiff-bases have played an important role in the development of coordination chemistry as they readily form stable complexes with most of the transition metals, in which some could exhibit interesting properties [1][2][3][4].…”

Section: Discussionmentioning

confidence: 99%

Crystal structure of (5-bromo-2,3-diaminopyridine-N,N′-bis(3-methoxysalicylideneiminato)- O,O′,N,N′)nickel(II) – methanol (1:1), Ni(C21H16BrN3O4) · CH3OH

Lian-wen¹

2009

Zeitschrift Für Kristallographie - New Crystal Structures

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Source of materialThe Schiff base ligand was synthesized by condensation 5-bromo-2,3-diaminopyridine and 2-hydroxy-3-methoxybenzaldehyde with the ratio 1:2inethanol. The synthesis of the title complex was carried out by reacting Ni(ClO 4 ) 2 · 6H 2 Oand the schiff base ligand (1:1, molar ratio) in methanol. After stirring, the process was continued for about 30 min at room temperature. The mixture was filtered and the filtrate was allowed to partially evaporate in air for sevral days to produce red-brown crystals suitable for X-ray diffraction with ayield about 60 %. DiscussionSchiff-bases have played an important role in the development of coordination chemistry as they readily form stable complexes with most of the transition metals, in which some could exhibit interesting properties [1][2][3][4].The coordination sphere for the Ni(II) ion in the title crystal structure is aslightly distorted square planar, in which the four positions are occupied by two Natoms and two Oatoms of the Schiffbase ligand. The mean deviation from the plane formed by the two Natoms, two Oatoms and the Ni ion is only 0.035 Å,indicative of that these five atoms can form aperfect plane. The bond lengths of Ni-Na re 1.874(3) Å and 1.929(3) Å,a nd Ni-O 1.861(2) Å and 1.905(2) Å,respectively, are consistant with the corresponding distances in 6,6'-dimethoxy-2,2'-(ethane-1,2-diyl-bis(nitrilomethylidyne)diphenolato)nickel(II) [5].

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“…It functions as the active site of hydrolytic enzymes, such as carboxypeptidase and carbonic anhydrase, where it is in a hard-donor coordination environment of nitrogen and oxygen [1]. It also has long been recognized as an important cofactor in biological molecules, either as a structural template in protein folding or as a Lewis acid catalyst that can readily adopt four-, fiveor six-fold coordination [2][3][4][5][6]. Recent reports have suggested that zinc is able to play a catalytic role in the activation of thiols as nucleophiles at physiological pH [7,8].…”

Section: Discussionmentioning

confidence: 99%

Crystal structure of dibromo(N-ethyl-N'-pyridinylmethyleneethane-1,2- diamino)zinc(II), ZnBr2(C10H15N3)

Peng¹,

Ping²,

Song³

2007

Zeitschrift Für Kristallographie - New Crystal Structures

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Source of materialAll the chemicals used were of AR grade. N-ethyl-1,2-diaminoethane (8.8 mg, 0.1 mmol) and pyridine-2-carbaldehyde (10.8 mg, 0.1 mmol) were refluxed in 10 ml methanol for 30 min. To the above solution was added ZnBr 2 (23.0 mg, 0.1 mmol) in 10 ml methanol. The mixture was refluxed for 1 h. The mixture was filtered after cooling to room temperature. After keeping the filtrate in air for 10 d, colorless crystals were formed. DiscussionZinc is the second most abundant transition or post-transition metal in biology. It functions as the active site of hydrolytic enzymes, such as carboxypeptidase and carbonic anhydrase, where it is in a hard-donor coordination environment of nitrogen and oxygen [1]. It also has long been recognized as an important cofactor in biological molecules, either as a structural template in protein folding or as a Lewis acid catalyst that can readily adopt four-, fiveor six-fold coordination [2-6]. Recent reports have suggested that zinc is able to play a catalytic role in the activation of thiols as nucleophiles at physiological pH [7,8]. We have reported the structure of a mononuclear Schiff base zinc(II) complex [9] and synthesized a further Schiff base zinc(II) complex and determined its crystal structure.In the title complex, the Zn(II) atom is coordinated by the pyridine N, imine N and amine N atoms of the Schiff base ligand and by two bromide anions, forming a distorted trigonal bipyramidal environment. The ZnN and ZnBr bond lengths are comparable to the values in other similar complexes [10][11][12]. The bond angles subtended at the Zn atom at the basal plane range from 112.35(9)°t o 131.66(9)°, and the bond angle of N1Zn1N3 at the axial positions deviates from the ideal value of 180°by 29.5(1)°, indicating a distorted trigonal bipyramid coordination. The deviation of ÐN1Zn1N3 is result from the steric effects of the five-membered chelate rings Zn1/N1/C2/C1/N2 and Zn1/N2/C7/C8/N3. Atom N8 deviates from the plane defined by Zn1/N2/C7/N3 by 0.644(6) Å.

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Coordination behaviour of symmetrical hexadentate N-donor Schiff bases towards zinc(II)pseudohalides: Syntheses, crystal structures and luminescence

Cited by 59 publications

References 38 publications

Copper(II) Schiff base complexes and their mixed thin layers with ZnO nanoparticles

Copper(II) Schiff base complexes and their mixed thin layers with ZnO nanoparticles

Crystal structure of (5-bromo-2,3-diaminopyridine-N,N′-bis(3-methoxysalicylideneiminato)- O,O′,N,N′)nickel(II) – methanol (1:1), Ni(C21H16BrN3O4) · CH3OH

Crystal structure of dibromo(N-ethyl-N'-pyridinylmethyleneethane-1,2- diamino)zinc(II), ZnBr2(C10H15N3)

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