Norbani Abdullah | University of Malaya, Malaysia (original) (raw)
Papers by Norbani Abdullah
World Applied Sciences Journal, 2012
Oxo-homoscorpionate borate ligand, potassium bis(phthalato)borate (KL) has been synthesized as it... more Oxo-homoscorpionate borate ligand, potassium bis(phthalato)borate (KL) has been synthesized as its potassium salt. It was converted into its Co(II), Ni(II) and Cu(II) dinuclear complexes by mixing and stirring with methanol solution of metal chloride. The compositions of ligand and its metal complexes were investigated by elemental analysis in order to ensure their purity and the structural elucidations were based on conductivity measurements, room temperature magnetic susceptibility, thermal and spectral studies (IR, H NMR, UV-Vis and 1 MS-ESI mass spectra). Spectroscopic results support a square planar (SP) geometry in the Cu(II) complex while an octahedral (O ) geometry is suggested in the Ni(II) and Co(II) complexes. Magnetic susceptibility h measurements of complexes reveal that these complexes exhibit antiferromagnetic coupling behavior due to the presence of two metal ions in close proximity. The molar conductance measurement in water shows 1:1 electrolyte natures. The thermal behaviour of compounds was investigated by thermal gravimetrical analysis (TGA), in order to determine their mode of decomposition and thermal stability. All these complexes and ligand show three step loss upon dynamic heating to 1000°C, with of simultaneous loss of both of inorganic and organic fragments exhibiting almost the same mode of decomposition pattern. The residue after heating above 500°C corresponded to metal chlorides, confirmed by microanalysis and IR spectroscopy. It is observed from the results that the thermal stability of the complexes increases in the following sequence:
academicjournals.org
... models for a number of important biological system containing couple sites (Thirumavalavan et... more ... models for a number of important biological system containing couple sites (Thirumavalavan et al., 2004; Halcrow and Christou, 1994; Jain et al., 2004; Chattopadhyay et al., 2007; Leita et al., 2004; Brooker, 2001; Suzuki et al., 2000; Bharati et al ... Mohamadin and Abdullah 2527 ...
Acta Crystallogr E Struct Rep, 2010
The CuII atom in the title salt, [Cu(C10H24N4)(H2O)2][CH3(CH2)8CO2]2·2H2O, is chelated by the fou... more The CuII atom in the title salt, [Cu(C10H24N4)(H2O)2][CH3(CH2)8CO2]2·2H2O, is chelated by the four N atoms of the 1,4,8,11-tetraazacyclotetradecane (cyclam) ligand and is coordinated by two water molecules in a JahnTeller-type tetragonally distorted octahedral geometry. ...
![Research paper thumbnail of Tetrakis(μ 2 -2,2-dimethylpropanoato-κ 2 O , O ′)bis[(pyridine-κ N )copper(II)]: a monoclinic polymorph](https://attachments.academia-assets.com/41908773/thumbnails/1.jpg)
](Acta Crystallogr E Struct Rep, 2010
The structure of the dinuclear title complex, [Cu 2 (C 5 H 9 O 2 ) 4 (C 5 H 5 N) 2 ], represents ... more The structure of the dinuclear title complex, [Cu 2 (C 5 H 9 O 2 ) 4 (C 5 H 5 N) 2 ], represents a monoclinic polymorph of the previously reported triclinic form [Blewett et al. (2006 [triangle] ). Acta Cryst. E62, m420m422]. Each carboxylate group is bidentate bridging and the ...
Inorganica Chimica Acta, 2015
Liquid Crystals XIX, 2015
RSC Adv., 2015
ABSTRACT Three iron(II) complexes with conjugated multidonor ligands (L1 and L2) studied as therm... more ABSTRACT Three iron(II) complexes with conjugated multidonor ligands (L1 and L2) studied as thermally stable magnetic and thermoelectric materials were [Fe2(CH3COO)4(L1)2] (1), [Fe(L1)3](BF4)2.4H2O (2), and [Fe2(CH3COO)4(L2)(H2O)2]n (3). These complexes have low optical band gaps (1.9 eV for 1 and 2, and 2.2 eV for 3) and were magnetic with 57% high-spin Fe(II) in 1, 33% in 2, and 100% in 3 at 25 oC. Complex 1 melted at 57.2 oC and exhibited an optical texture characteristic of a calamitic liquid crystal, while 2 melted at 96.9 oC, defining it as an ionic liquid. The thermal stabilities of 1 (Tdec = 199 oC) and 3 (Tdec = 191 oC) were lower than 2 (Tdec = 248 oC). Their Seebeck coefficients, Se (in mV K-1) were -0.65 for 1, -0.54 for 2, and +0.25 for 3, identifying them as potential thermoelectric materials. Complex 1 formed stable thin films on quartz by the spin coating technique. The films formed at aging time t = 0 ( F1) and t = 7 days ( F2) were made up of monomers of 1. The optical band gaps of the films (1.39 eV for F1 and 1.57 eV for F2) were lower than 1. The films were free of cracks and have a fairly homogeneous morphology. The films with the best morphology were F1 annealed at 40 oC and F2 annealed at 60 oC.
RSC Adv., 2015
Through external doping, novel conductive polymer nanofibers were successfully fabricated using i... more Through external doping, novel conductive polymer nanofibers were successfully fabricated using ionic liquids. In this work, polymer blend of polyvinyl alcohol (PVA) and chitosan (CS) of 4: 1 weight ratio was fabricated in the form of nanofibers through electrospinning and used as a scaffolded membrane to capture room-temperature ionic liquids (RTILs), such as 1-ethyl-3-methylimidazolium chloride (EMIMCl) and 1-butyl-3-methylimidazolium bromide (BMIMBr). The morphological analysis through scanning electron microscope (SEM) showed that the scaffold structure of the electrospun membrane facilitated sufficient trapping of RTILs. This membrane has demonstrated significantly increased conductivity from 6 × 10 -6 S/cm to 0.10 S/cm, interestingly surpassing the value of pure ionic liquids, where the polymer chain breathing model has been suggested as a hypothesis to explain the phenomena. The dominance of ions as charge carriers was explained using ionic transference number measurement. The interaction between polymer nanofiber matrix and an ionic liquid has been explained using Fourier-transform infrared spectroscopy (FTIR), where the ionic liquid was found to be physically dispersed in the polymer nanofiber matrix. These materials have also shown some thermoelectric (TE) activity, by demonstrating Seebeck coefficient of up to 17.92 µV/K. The existence of freely movable ions in this type of membrane shows their applications as energy storage/conversion devices, such as organic thermoelectric (TE), sensor, and dye-sensitised solar cell.
Asian Journal of Chemistry, 2015
The Scientific World Journal, 2015
A dimeric iron(II) complex, trans-[Fe2(CH3COO)4(L1)2] (1), and a trinuclear iron(II) complex, [Fe... more A dimeric iron(II) complex, trans-[Fe2(CH3COO)4(L1)2] (1), and a trinuclear iron(II) complex, [Fe3(CH3COO)4(H2O)4(L2)] (2), were studied as potential dye-sensitised solar cell materials. The structures of both complexes were deduced by a combination of instrumental analyses and molecular modelling. Variable-temperature magnetic susceptibility data suggested that 1 was made up of 56.8% high-spin (HS) and 43.2% low-spin (LS) Fe(II) atoms at 294 K and has a moderate antiferromagnetic interaction (J = -81.2 cm(-1)) between the two Fe(II) centres, while 2 was made up of 27.7% HS and 72.3% LS Fe(II) atoms at 300 K. The optical band gaps (E o ) for 1 were 1.9 eV (from absorption spectrum) and 2.2 eV (from fluorescence spectrum), electrochemical bandgap (E e) was 0.83 eV, excited state lifetime (τ) was 0.67 ns, and formal redox potential (E'(Fe(III)/Fe(II))) was +0.63 V. The corresponding values for 2 were 3.5 eV (from absorption spectrum), 1.8 eV (from fluorescence spectrum), 0.69 eV, 2.8 ns, and +0.41 V.
AIP Conference Proceedings, 2010
ZnO thin films were fabricated by the sol-gel method using Zn(CH3COO)2.2H2O (zinc acetate) as sta... more ZnO thin films were fabricated by the sol-gel method using Zn(CH3COO)2.2H2O (zinc acetate) as starting material. A homogenous and stable solution was prepared by dissolving the zinc acetate in a solution of ethanol and ethanolamine. Deposition of ZnO solution on Si substrate was performed by spin-coating technique and annealed at various temperatures from 200° C to 600° C. The surface
Journal of Nanomaterials, 2012
ZnO nanoparticles were prepared on Si substrates by a mist-atomisation technique. Precursor of aq... more ZnO nanoparticles were prepared on Si substrates by a mist-atomisation technique. Precursor of aqueous solution zinc nitrate and HMTA were released on substrates heated at 200, 300, and 400 • C confined in chamber box. The surface of Si substrate was varied, that is, gold-seeded Si (Si/Au), ZnO nanorods on Si/Au (Si/Au/ZnO), and just Si. The samples were subsequently analysed by X-ray diffraction, scanning electron microscopy, and photoluminescence (PL) spectroscopy to study their structural, surface morphology, and PL emission properties. Analysis from the XRD patterns of the films showed strong a-and c-axis lattice and of pure ZnO hexagonal wurtzite type. The crystallite size varied from 6 to 43 nm and was found to generally increase with increasing substrates' temperatures(T s ). SEM micrographs revealed granular-like structure throughout. Shifts pattern of PL emission at ultraviolet and visible range was found to support size changes observed. Both substrate surface type and deposition temperature were found to significantly affect crystalline growth of ZnO nanoparticles. Chemical equations and justification for growth patterns are also suggested.
The CuII atom in the title compound, [Cu(C7H4IO2)2(C10H8N2)(H2O)], is N,N′-chelated by a 2,2′-bip... more The CuII atom in the title compound, [Cu(C7H4IO2)2(C10H8N2)(H2O)], is N,N′-chelated by a 2,2′-bipyridine ligand and is coordinated by two monodentate carboxylate ions and a water molecule in a distorted square-pyramidal geometry. The apical site is occupied by one of the carboxylate O atoms. The water molecule forms intramolecular hydrogen bonds to the uncoordinated carboxyl O atoms. The crystal studied was a nonmerohedral twin with minor components in 0.381 (3) and 0.108 (2) proportions.
World Applied Sciences Journal, 2012
Oxo-homoscorpionate borate ligand, potassium bis(phthalato)borate (KL) has been synthesized as it... more Oxo-homoscorpionate borate ligand, potassium bis(phthalato)borate (KL) has been synthesized as its potassium salt. It was converted into its Co(II), Ni(II) and Cu(II) dinuclear complexes by mixing and stirring with methanol solution of metal chloride. The compositions of ligand and its metal complexes were investigated by elemental analysis in order to ensure their purity and the structural elucidations were based on conductivity measurements, room temperature magnetic susceptibility, thermal and spectral studies (IR, H NMR, UV-Vis and 1 MS-ESI mass spectra). Spectroscopic results support a square planar (SP) geometry in the Cu(II) complex while an octahedral (O ) geometry is suggested in the Ni(II) and Co(II) complexes. Magnetic susceptibility h measurements of complexes reveal that these complexes exhibit antiferromagnetic coupling behavior due to the presence of two metal ions in close proximity. The molar conductance measurement in water shows 1:1 electrolyte natures. The thermal behaviour of compounds was investigated by thermal gravimetrical analysis (TGA), in order to determine their mode of decomposition and thermal stability. All these complexes and ligand show three step loss upon dynamic heating to 1000°C, with of simultaneous loss of both of inorganic and organic fragments exhibiting almost the same mode of decomposition pattern. The residue after heating above 500°C corresponded to metal chlorides, confirmed by microanalysis and IR spectroscopy. It is observed from the results that the thermal stability of the complexes increases in the following sequence:
academicjournals.org
... models for a number of important biological system containing couple sites (Thirumavalavan et... more ... models for a number of important biological system containing couple sites (Thirumavalavan et al., 2004; Halcrow and Christou, 1994; Jain et al., 2004; Chattopadhyay et al., 2007; Leita et al., 2004; Brooker, 2001; Suzuki et al., 2000; Bharati et al ... Mohamadin and Abdullah 2527 ...
Acta Crystallogr E Struct Rep, 2010
The CuII atom in the title salt, [Cu(C10H24N4)(H2O)2][CH3(CH2)8CO2]2·2H2O, is chelated by the fou... more The CuII atom in the title salt, [Cu(C10H24N4)(H2O)2][CH3(CH2)8CO2]2·2H2O, is chelated by the four N atoms of the 1,4,8,11-tetraazacyclotetradecane (cyclam) ligand and is coordinated by two water molecules in a JahnTeller-type tetragonally distorted octahedral geometry. ...
Acta Crystallogr E Struct Rep, 2010
The structure of the dinuclear title complex, [Cu 2 (C 5 H 9 O 2 ) 4 (C 5 H 5 N) 2 ], represents ... more The structure of the dinuclear title complex, [Cu 2 (C 5 H 9 O 2 ) 4 (C 5 H 5 N) 2 ], represents a monoclinic polymorph of the previously reported triclinic form [Blewett et al. (2006 [triangle] ). Acta Cryst. E62, m420m422]. Each carboxylate group is bidentate bridging and the ...
Inorganica Chimica Acta, 2015
Liquid Crystals XIX, 2015
RSC Adv., 2015
ABSTRACT Three iron(II) complexes with conjugated multidonor ligands (L1 and L2) studied as therm... more ABSTRACT Three iron(II) complexes with conjugated multidonor ligands (L1 and L2) studied as thermally stable magnetic and thermoelectric materials were [Fe2(CH3COO)4(L1)2] (1), [Fe(L1)3](BF4)2.4H2O (2), and [Fe2(CH3COO)4(L2)(H2O)2]n (3). These complexes have low optical band gaps (1.9 eV for 1 and 2, and 2.2 eV for 3) and were magnetic with 57% high-spin Fe(II) in 1, 33% in 2, and 100% in 3 at 25 oC. Complex 1 melted at 57.2 oC and exhibited an optical texture characteristic of a calamitic liquid crystal, while 2 melted at 96.9 oC, defining it as an ionic liquid. The thermal stabilities of 1 (Tdec = 199 oC) and 3 (Tdec = 191 oC) were lower than 2 (Tdec = 248 oC). Their Seebeck coefficients, Se (in mV K-1) were -0.65 for 1, -0.54 for 2, and +0.25 for 3, identifying them as potential thermoelectric materials. Complex 1 formed stable thin films on quartz by the spin coating technique. The films formed at aging time t = 0 ( F1) and t = 7 days ( F2) were made up of monomers of 1. The optical band gaps of the films (1.39 eV for F1 and 1.57 eV for F2) were lower than 1. The films were free of cracks and have a fairly homogeneous morphology. The films with the best morphology were F1 annealed at 40 oC and F2 annealed at 60 oC.
RSC Adv., 2015
Through external doping, novel conductive polymer nanofibers were successfully fabricated using i... more Through external doping, novel conductive polymer nanofibers were successfully fabricated using ionic liquids. In this work, polymer blend of polyvinyl alcohol (PVA) and chitosan (CS) of 4: 1 weight ratio was fabricated in the form of nanofibers through electrospinning and used as a scaffolded membrane to capture room-temperature ionic liquids (RTILs), such as 1-ethyl-3-methylimidazolium chloride (EMIMCl) and 1-butyl-3-methylimidazolium bromide (BMIMBr). The morphological analysis through scanning electron microscope (SEM) showed that the scaffold structure of the electrospun membrane facilitated sufficient trapping of RTILs. This membrane has demonstrated significantly increased conductivity from 6 × 10 -6 S/cm to 0.10 S/cm, interestingly surpassing the value of pure ionic liquids, where the polymer chain breathing model has been suggested as a hypothesis to explain the phenomena. The dominance of ions as charge carriers was explained using ionic transference number measurement. The interaction between polymer nanofiber matrix and an ionic liquid has been explained using Fourier-transform infrared spectroscopy (FTIR), where the ionic liquid was found to be physically dispersed in the polymer nanofiber matrix. These materials have also shown some thermoelectric (TE) activity, by demonstrating Seebeck coefficient of up to 17.92 µV/K. The existence of freely movable ions in this type of membrane shows their applications as energy storage/conversion devices, such as organic thermoelectric (TE), sensor, and dye-sensitised solar cell.
Asian Journal of Chemistry, 2015
The Scientific World Journal, 2015
A dimeric iron(II) complex, trans-[Fe2(CH3COO)4(L1)2] (1), and a trinuclear iron(II) complex, [Fe... more A dimeric iron(II) complex, trans-[Fe2(CH3COO)4(L1)2] (1), and a trinuclear iron(II) complex, [Fe3(CH3COO)4(H2O)4(L2)] (2), were studied as potential dye-sensitised solar cell materials. The structures of both complexes were deduced by a combination of instrumental analyses and molecular modelling. Variable-temperature magnetic susceptibility data suggested that 1 was made up of 56.8% high-spin (HS) and 43.2% low-spin (LS) Fe(II) atoms at 294 K and has a moderate antiferromagnetic interaction (J = -81.2 cm(-1)) between the two Fe(II) centres, while 2 was made up of 27.7% HS and 72.3% LS Fe(II) atoms at 300 K. The optical band gaps (E o ) for 1 were 1.9 eV (from absorption spectrum) and 2.2 eV (from fluorescence spectrum), electrochemical bandgap (E e) was 0.83 eV, excited state lifetime (τ) was 0.67 ns, and formal redox potential (E'(Fe(III)/Fe(II))) was +0.63 V. The corresponding values for 2 were 3.5 eV (from absorption spectrum), 1.8 eV (from fluorescence spectrum), 0.69 eV, 2.8 ns, and +0.41 V.
AIP Conference Proceedings, 2010
ZnO thin films were fabricated by the sol-gel method using Zn(CH3COO)2.2H2O (zinc acetate) as sta... more ZnO thin films were fabricated by the sol-gel method using Zn(CH3COO)2.2H2O (zinc acetate) as starting material. A homogenous and stable solution was prepared by dissolving the zinc acetate in a solution of ethanol and ethanolamine. Deposition of ZnO solution on Si substrate was performed by spin-coating technique and annealed at various temperatures from 200° C to 600° C. The surface
Journal of Nanomaterials, 2012
ZnO nanoparticles were prepared on Si substrates by a mist-atomisation technique. Precursor of aq... more ZnO nanoparticles were prepared on Si substrates by a mist-atomisation technique. Precursor of aqueous solution zinc nitrate and HMTA were released on substrates heated at 200, 300, and 400 • C confined in chamber box. The surface of Si substrate was varied, that is, gold-seeded Si (Si/Au), ZnO nanorods on Si/Au (Si/Au/ZnO), and just Si. The samples were subsequently analysed by X-ray diffraction, scanning electron microscopy, and photoluminescence (PL) spectroscopy to study their structural, surface morphology, and PL emission properties. Analysis from the XRD patterns of the films showed strong a-and c-axis lattice and of pure ZnO hexagonal wurtzite type. The crystallite size varied from 6 to 43 nm and was found to generally increase with increasing substrates' temperatures(T s ). SEM micrographs revealed granular-like structure throughout. Shifts pattern of PL emission at ultraviolet and visible range was found to support size changes observed. Both substrate surface type and deposition temperature were found to significantly affect crystalline growth of ZnO nanoparticles. Chemical equations and justification for growth patterns are also suggested.
The CuII atom in the title compound, [Cu(C7H4IO2)2(C10H8N2)(H2O)], is N,N′-chelated by a 2,2′-bip... more The CuII atom in the title compound, [Cu(C7H4IO2)2(C10H8N2)(H2O)], is N,N′-chelated by a 2,2′-bipyridine ligand and is coordinated by two monodentate carboxylate ions and a water molecule in a distorted square-pyramidal geometry. The apical site is occupied by one of the carboxylate O atoms. The water molecule forms intramolecular hydrogen bonds to the uncoordinated carboxyl O atoms. The crystal studied was a nonmerohedral twin with minor components in 0.381 (3) and 0.108 (2) proportions.