The5T2 ⇌ 1A1 spin transition in [Fe(bpp)2][BF4]2 (bpp = 2,6-bis(pyrazol-3-yl)pyridine) is abrupt and complete and shows hysteresis with the transition tempera.
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The present study is concern with the identification, characterization and activation of natural allophane as an adsorbent of heavy metal ions Cr, Fe, Cd, Cu, Pb and Mn. The purposes of this study were to identify and characterize the... more
The present study is concern with the identification, characterization and activation of natural allophane as an adsorbent of heavy metal ions Cr, Fe, Cd, Cu, Pb and Mn. The purposes of this study were to identify and characterize the natural allophane of Javanese volcanoes (Papandayan, Arjuna and Wilis), and to determine the optimum conditions of adsorption and adsorption isotherms that happened. The identification of natural allophane was performed by using NaF, pH, FTIR, and XRD. The characterization of the acidity of allophane was analyzed by using ammonia adsorption. The activation was done in the NaOH solution of 1 N and 3 N, and in the soaking time of 1, 3, and 5 hours. The adsorption was done according to batch method with the variations of contact time of 30, 60, 90 and 120 minutes. The adsorption isotherms performed by using the variations of the amount of adsorbate. Atomic Absorption Spectroscopy (AAS) was used in the analysis to determine the concentration of heavy metal...
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The magnetic and Mossbauer spectral properties of hydrated and anhydrous complex salts [Fe( bpp )2] X2, where bpp = [2,6-bis(pyrazol-3-yl)pyridine] and X = PF6, BF4, Br, I, NO3, are indicative of a temperature-induced singlet (1A1) ↔... more
The magnetic and Mossbauer spectral properties of hydrated and anhydrous complex salts [Fe( bpp )2] X2, where bpp = [2,6-bis(pyrazol-3-yl)pyridine] and X = PF6, BF4, Br, I, NO3, are indicative of a temperature-induced singlet (1A1) ↔ quintet (5T2) transition in the complex cation. The nature of the transition depends on the anion and the degree of hydration. The transition is displaced to lower temperatures in the anhydrous species and for the hydrated is only partial above room temperature. The transition in the hydrated hexafluorophosphate salt occurs in two steps, and that in the anhydrous hexafluorophosphate is incomplete, a high residual fraction of quintet state species being retained below the transition temperature. For the anhydrous complexes the transition is discontinuous and that in the complex iodide is associated with a narrow thermal hysteresis with transition temperatures Tc ↓ = 203 K and Tc ↑ = 205 K. The structures of [Fe( bpp )2]I2.4H2O and [Fe( bpp )2][BF4]2.3H2O...
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Australian Journal of Chemistry - an International Journal for Chemical Science publishes research papers from all fields of chemical science.
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The powder complex of tris(phenanthroline)nickel(II) trifluoroacetate has been synthesized by interaction of the corresponding nitrate salt in an aqueous solution and slightly excess of 1,10-phenanthroline in water/ethanol, whereupon the... more
The powder complex of tris(phenanthroline)nickel(II) trifluoroacetate has been synthesized by interaction of the corresponding nitrate salt in an aqueous solution and slightly excess of 1,10-phenanthroline in water/ethanol, whereupon the precipitate was produced on addition of an excess of saturated sodium trifluoroacetate solution while reducing the solvent. AAS measurement showed the content of metal to be 6.43 % being relatively close to the corresponding theoretical value of 6.60 % masss in [Ni(phen)3](CF3COO)2.3.5H2O. Moreover, the TGA confirmed the lost of 6.943% mass of complex corresponding to 3.43 H2O. The analysis of conductance producing the charge ratio of cation by anion to be 2:1, clearly fonfirms the formula. The magnetic moment, μeff, of this complex which was to be 3.19-3.31 BM, indicates that the complex is paramagnetic corresponding to two unpaired electrons which is clearly higher than the spin only value (2.87 BM) due to the spin-orbit coupling. UV-Vis spectrum ...
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Pengembangan dan penggunaan media pembelajaran berbantuan perangkat Android saat ini mulai menjadi tren penelitian di bidang pendidikan sains. Media pembelajaran “Chemondro” merupakan software media pembelajaran kimia yang dapat... more
Pengembangan dan penggunaan media pembelajaran berbantuan perangkat Android saat ini mulai menjadi tren penelitian di bidang pendidikan sains. Media pembelajaran “Chemondro” merupakan software media pembelajaran kimia yang dapat dioperasikan menggunakan perangkat dengan sistem operasi Android. Penelitian ini bertujuan untuk menguji pengaruh penggunaan media pembelajaran kimia “Chemondro” pada materi kelarutan terhadap peningkatan kemandirian belajar siswa SMA. Penelitian dilakukan di SMAN 10 Yogyakarta dengan menggunakan desain uji coba posttest-pretest-control group design . Kemandirian belajar diukur dengan angket kemandirian belajar yang menggunakan peringkat Likert. Hasil penelitian menunjukkan bahwa terdapat perbedaan yang signifikan pada peningkatan kemandirian belajar antara siswa yang menggunakan media pembelajaran “Chemondro” dan siswa yang tidak menggunakannya.
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Salt of [Fe(trzH) 2 (trz)][CF 3 SO 3 ].H 2 O (where trzH = 1,2,4- triazole, and trz = triazolato, that is deprotonated 1,2,4-triazole anion) has been successfully isolated as white powder. Its magnetic, Mossbauer and electronic spectral... more
Salt of [Fe(trzH) 2 (trz)][CF 3 SO 3 ].H 2 O (where trzH = 1,2,4- triazole, and trz = triazolato, that is deprotonated 1,2,4-triazole anion) has been successfully isolated as white powder. Its magnetic, Mossbauer and electronic spectral properties are temperature dependent and reveal that the salt exhibits thermally spin state, singlet 1 A 1g ( .s) l quintet 5 T 2g (h.s), transition in iron(II). The transition is relatively abrupt, incomplete down to ~ 89 K and without hysteresis. The room-temperature electronic spectrum of the salt reveals a high-spin ligand field band which is split into two at about 11000 cm -1 and 13000 cm -1 . At low temperature, the intensity of the high-spin ligand field band is reduced significantly and a strong low-spin ligand field band appears at about 18500 cm -1 . The change in pattern of the spectrum is associated with the thermochromic behaviour, being white at room temperature but violet at the low one. The X-ray diffractogram suggests that the salt ...
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Tris(ligand)iron(II) complexes of 2-(pyrazol-3-yl)pyridine (3ppH) and 3-(thiazol-2-yl)pyrazole (3tpH) undergo temperature-induced singlet (1A1) ⇔ quintet (5T2) transitions. The transition in [Fe(3ppH)3] [CF3SO3]2.2H2O is continuous and... more
Tris(ligand)iron(II) complexes of 2-(pyrazol-3-yl)pyridine (3ppH) and 3-(thiazol-2-yl)pyrazole (3tpH) undergo temperature-induced singlet (1A1) ⇔ quintet (5T2) transitions. The transition in [Fe(3ppH)3] [CF3SO3]2.2H2O is continuous and centred above room temperature while that in the anhydrous triflate salt is discontinuous and is centred below room temperature. The latter transition occurs via a thermal hysteresis loop of width 12 K, Tc↓ and Tc↑ being 229 and 241 K, respectively. The displacement of the transition to lower temperature in the anhydrous salt is believed to be associated with the loss of hydrogen bonding involving the uncoordinated pyrazole >NH group and solvate water. In [Fe(3tpH)2(3tp)] [ClO4].2H2O and [Fe(3tpH)2(3tp)] [BF4].2H2O (3tp is the deprotonated ligand) continuous transitions are observed, centred below room temperature. In these instances the displacement is consistent with the intrinsically weaker field of the bidentate system containing two five-membered heterocycles. Structural data were obtained for [Fe(3ppH)3][CF3SO3]2.2H2O, [Fe(3tpH)3] [BF4]2.1·5H2O and [Ni(3tpH)3] [BF4]2.2(3tpH). The average metal–nitrogen distances in the complexes are 1·97, 2·18 and 2·09 Å, severally. The large difference in the distances for the two iron complexes arises from the different ground states: a singlet for the 3ppH complex and a quintet for the 3tpH complex. In all three salts there is extensive hydrogen bonding involving the pyrazole >NH groups, the anions and the solvate molecules. [Fe(3ppH)3] [CF3SO3]2.2H2O: monoclinic, space group P21/c, a 12·33(1), b 24·44(1), c 12·55(1) Å, β 115·27(4)°, Z 4. [Fe(3tpH)3] [BF4]2.1·5H2O: monoclinic, space group C 2/c, a 41·56(2), b 16·418(3), c 18·154(7) Å, β 106·94(2)°, Z 8. [Ni(3tpH)3] [BF4]2.2(3tpH):P bcn, a 14·928(2), b 15·310 (3), c 17·882 (3) Å, Z 4.
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The present study is concern with the identification, characterization and activation of natural allophane as an adsorbent of heavy metal ions Cr, Fe, Cd, Cu, Pb and Mn. The purposes of this study were to identify and characterize the... more
The present study is concern with the identification, characterization and activation of natural allophane as an adsorbent of heavy metal ions Cr, Fe, Cd, Cu, Pb and Mn. The purposes of this study were to identify and characterize the natural allophane of Javanese volcanoes (Papandayan, Arjuna and Wilis), and to determine the optimum conditions of adsorption and adsorption isotherms that happened. The identification of natural allophane was performed by using NaF, pH, FTIR, and XRD. The characterization of the acidity of allophane was analyzed by using ammonia adsorption. The activation was done in the NaOH solution of 1 N and 3 N, and in the soaking time of 1, 3, and 5 hours. The adsorption was done according to batch method with the variations of contact time of 30, 60, 90 and 120 minutes. The adsorption isotherms performed by using the variations of the amount of adsorbate. Atomic Absorption Spectroscopy (AAS) was used in the analysis to determine the concentration of heavy metal...
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The objective of this work was to synthesise of complex containing manganese(II), 1,10-phenanthroline (phen) as ligand and a counter anion of trifluoromethanesulfonate (triflate). The complex was prepared by interaction of the... more
The objective of this work was to synthesise of complex containing manganese(II), 1,10-phenanthroline (phen) as ligand and a counter anion of trifluoromethanesulfonate (triflate). The complex was prepared by interaction of the corresponding nitrate salt and slightly excess of phenanthroline in aqueous solution, whereupon the precipitate was produced on addition of an excess of saturated potassium triflate solution when reducing the solvent. It was then characterised in terms of electrical conductivity, metal content, magnetic moment, electronic and infrared spectral properties, and powder XRD. The atomic absorption spectral data and the equivalent conductance suggest that the resulted complex was found to be ionic hydrated complex with the content of three ions per molecule, with an equivalent conductance in the range values of the three ionic standard, but much higher than the two ionic standard and much lower than the four ionic standard. The formula of [Mn(phen)3](CF3SO3)2.6,5H2O was then proposed. The...
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We have studied the X-ray powder diffraction of the spin transition material [Fe(bpp)2](NCS)2 · 2H2O (bpp: 2,6-bis(pyrazol-3-yl)pyridine) at room temperature. Two crystallographic phases have been observed depending on the sample history... more
We have studied the X-ray powder diffraction of the spin transition material [Fe(bpp)2](NCS)2 · 2H2O (bpp: 2,6-bis(pyrazol-3-yl)pyridine) at room temperature. Two crystallographic phases have been observed depending on the sample history of this material. The results obtained corroborate the earlier observations from magnetic and calorimetric studies. Relatively prolonged exposure of the sample to X-rays caused a structural change. LIESST and Reverse-LIESST effects, characterised by 57Fe Mössbauer spectroscopy, have been observed in this material.Sample history dependent structural bistability of spin transition material [Fe(bpp)2](NCS)2 · 2H2O has been characterised at room temperature from XRD. Relatively prolonged exposure of the sample to X-rays caused a structural change. LIESST and Reverse-LIESST effects, characterised by 57Fe Mössbauer spectroscopy, have been observed in this material. This material is a remarkably fluid system with respect to its response to thermal cycling,...
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Complexes of stoichiometry Fe( trzH )2( trz )X, where trzH is 1,2,4-triazole and X = BF4, ClO4, PF6, have been prepared. All three salts display temperature-induced singlet (1A1) ↔ quintet (5T2) transitions which are generally... more
Complexes of stoichiometry Fe( trzH )2( trz )X, where trzH is 1,2,4-triazole and X = BF4, ClO4, PF6, have been prepared. All three salts display temperature-induced singlet (1A1) ↔ quintet (5T2) transitions which are generally discontinuous and associated with a broad hysteresis loop. The salts are strongly thermochromic, being white above and pink-lilac below the transition region. Several samples of each salt were obtained and the detailed behaviour varied somewhat from one sample to another. For the fluoroborate and perchlorate salts the transition is centred above room temperature while for the hexafluorophosphate salt it occurs below room temperature. The perchlorate salt was also isolated in a form which showed a continuous transition but the nature of its electronic properties changed as the sample aged. In one form of the hexafluorophosphate salt the hysteresis loop spans room temperature and it has been possible to characterize both the singlet and the quintet state species...
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Essentially high-spin [Fe(bpp)2][NCS]2·2H2O and [Fe(bpp)2][NCSe]2 (bpp = 2,6-bis(pyrazol-3-yl)pyridine) were isolated from an aqueous reaction mixture. Both salts undergo an abrupt transition to low spin below room temperature, that for... more
Essentially high-spin [Fe(bpp)2][NCS]2·2H2O and [Fe(bpp)2][NCSe]2 (bpp = 2,6-bis(pyrazol-3-yl)pyridine) were isolated from an aqueous reaction mixture. Both salts undergo an abrupt transition to low spin below room temperature, that for the thiocyanate occurring in two steps and the high-spin AE low-spin AE high-spin cycle being accompanied by hysteresis in both steps. Recrystallization of the salts from nitromethane yielded a mixture from which bright yellow crystals were separated for structure determination. In addition, from the recrystallized selenocyanate, deep red-brown crystals of composition [Fe(bpp)2][NCSe]2·H2O·0.25 CH3NO2 were obtained. Recrystallized [Fe(bpp)2][NCS]2·2H2O and [Fe(bpp)2][NCSe]2 were identified as high spin with average Fe–N distances of 2.16 and 2.17 A, respectively. In the unit cell of [Fe(bpp)2][NCSe]2·H2O·0.25 CH3NO2, there are four independent iron atoms, three identified as low spin and the fourth as high spin. All salts crystallize in a layer-type ...
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The powder complex of tris(phenanthroline) copper(II) trifluoromethanesulfonate dihydrate has been synthesized by direct interaction of the corresponding precursors, copper(II) nitrate, phenanthroline, and potassium triflate. The metal... more
The powder complex of tris(phenanthroline) copper(II) trifluoromethanesulfonate dihydrate has been synthesized by direct interaction of the corresponding precursors, copper(II) nitrate, phenanthroline, and potassium triflate. The metal content found to be 6.76% corresponds to the theoretical value of 6.77% in [Cu(phen) 3 ](CF 3 SO 3 ) 2 .2H 2 O. The equivalent electrical conductance producing the charge ratio of cation by anion to be 2: 1, should confirm the formula. The magnetic moment, μ eff , of this complex which was to be 1.85-1.90 B.M, indicates that the complex is paramagnetic corresponding to spin-only value for one unpaired electron. UV-Vis spectrum of the complex reveals the only one broad absorption observed at about 681.50 nm (14673.51 cm-1), being associated with the spin allowed transition, Eg → 2T 2g . The extinction coefficient of 48 Lmol1 cm-1 indicates the adoption of octahedral environment in this complex. The infrared spectrum shows absorptions of ligand group wh...
This study is aimed at determining the effectiveness of using virtual reality (VR) toward students’ scientific attitude in chemical bonding. The data was collected through questionnaire consisting of 14 items. A quasi-experiment with a... more
This study is aimed at determining the effectiveness of using virtual reality (VR) toward students’ scientific attitude in chemical bonding. The data was collected through questionnaire consisting of 14 items. A quasi-experiment with a post-test design was employed in this study. The population was the students of 10 th public senior high school in Gunungkidul Regency. A total of 96 grade 10 th students were cluster randomly selected from a public senior high school. The samples were set into three different classes, namely control group (CG) using a real laboratory, experiment group-1 (EG-1) using a virtual reality integrated hybrid learning, and experiment group-2 (EG-2) using both of them. The data related to students’ scientific attitude were analyzed using ANOVA. Scientific attitude scores were significantly different between the class using a real laboratory, the class that was using virtual reality, and the class that using both of them. This study implies that VR can be used...
Iron(II) and nickel(II) [MN6]X2 type complexes have been prepared from 2-(pyrazol-1-yl]pyridine (1pp), 2-(pyrazol-1-yl) imidazoline (pi), 2- (pyrazol-3-yl)pyridine (3pp) and 2,6-bis(pyrazol-3-yl)pyridine ( bpp ). Variable-temperature... more
Iron(II) and nickel(II) [MN6]X2 type complexes have been prepared from 2-(pyrazol-1-yl]pyridine (1pp), 2-(pyrazol-1-yl) imidazoline (pi), 2- (pyrazol-3-yl)pyridine (3pp) and 2,6-bis(pyrazol-3-yl)pyridine ( bpp ). Variable-temperature magnetic and Mossbauer spectral studies establish that [Fe(1pp)3]X2 is low spin and [Fe(pi)3]X2 is high spin over an extended temperature range, while both [Fe(3pp)3]X2 and [Fe( bpp )2]X2 undergo temperature-induced low-spin ↔ high-spin transitions. The nature of the transition depends on the extent of hydration and for salts of both cations the singlet state is generally stabilized as the extent of hydration increases. Hydrogen bonding effects are believed to be responsible for this. For anhydrous [Fe( bpp )2] [BF4]2 the transition is discontinuous and associated with hysteresis with Tc ↓ 173 K for decreasing temperature and Tc ↑ 183 K for increasing temperatures. The transition to the singlet state species is complete at low temperatures provided that...
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A virtual laboratory known as VICH-LAB (Virtual Chemistry Laboratory) has been developed in hybrid learning. This VICH-LAB was used in electrochemistry classes involving much practice work with various tools and materials. VICH-LAB... more
A virtual laboratory known as VICH-LAB (Virtual Chemistry Laboratory) has been developed in hybrid learning. This VICH-LAB was used in electrochemistry classes involving much practice work with various tools and materials. VICH-LAB contains a MSDS (Material Safety Data Sheet), tools introduction, interactive practicum, and assignments. The aim of this study was to measure self-efficacy in the use of VICH-LAB. The design of this research was quasi-experimental with a post-test design. Differences among 3 classes with different treatments was observed. The first class used a wet laboratory, the second class used a virtual laboratory integrated hybrid learning approach, and a third class used both of them. All three classes took place during the same academic term and had the same teachers. The variable measured in the three classes was self-efficacy, measured with a questionnaire consisting of 22 items. Self-efficacy scores were significantly different between the class using a wet la...
Penelitian ini bertujuan untuk menghasilkan produk berupa media mobile learning berbasis android sebagai suplemen belajar pada materi larutan penyangga dan hidrolisis untuk siswa SMA kelas XI IPA. Penelitian ini dilakukan di SMA Negeri 11... more
Penelitian ini bertujuan untuk menghasilkan produk berupa media mobile learning berbasis android sebagai suplemen belajar pada materi larutan penyangga dan hidrolisis untuk siswa SMA kelas XI IPA. Penelitian ini dilakukan di SMA Negeri 11 Yogyakarta. Pembelajaran kimia dengan menggunakan media mobile learning ini memiliki karakteristik yang memanfaatkan teknologi dalam pembelajaran sehingga dapat digunakan bagi siapa saja, dimana saja dan kapan saja. Metode yang digunakan dalam penelitian pengembangan ini berdasarkan adaptasi model pengembangan Borg & Gall yang dikelompokkan menjadi tiga bagian, yaitu studi pendahuluan, pengembangan produk awal, dan evaluasi/penilaian produk. Produk awal telah direview oleh ahli materi dan ahli IT. Selanjutnya hasil revisi dinilai berdasarkan materi, pengoperasian dan tampilan media oleh reviewer (guru kimia) dan peer reviewer . Kemudian diujicobakan kepada siswa SMA untuk mengetahui kelayakan media mobile learning berbasis android. Hasil penelitian...
The 21st century learning system demands the use of technology in learning instruction. This research focuses on the comparison between the use of android-based-game and blended learning in the Chemistry subject on the hydrocarbon lesson... more
The 21st century learning system demands the use of technology in learning instruction. This research focuses on the comparison between the use of android-based-game and blended learning in the Chemistry subject on the hydrocarbon lesson toward students’ self-efficacy and achievement. A quasi-experiment with post-test only design was adopted in this research. A number of 143 eleventh graders from two public senior high schools in Purworejo Regency, Indonesia were selected in a cluster random sampling as the research sample. The sample was classified into three groups depending on the media used, i.e. android-based-game only on face-to-face learning (ABG-FTFL), blended learning only (BL), and both android-based-game and blended learning (ABG-BL). Self-Efficacy Scale (SES) was used to obtain the data of students’ self-efficacy while the hydrocarbon test was used to obtain students’ achievement. One-way Analysis of Variance, Kruskal Wallis test, and descriptive quantity technique were ...
Salt of [Cu(bptrzH)Cl2], (bptrzH = 3,5-bis(pyridin-2-yl)-H-1,2,4-triazole) has been prepared and characterized its electronic spectral and magnetic properties. This salt is paramagnetic with magnetic moment, μs, being 1.77–1.78 BM at 293... more
Salt of [Cu(bptrzH)Cl2], (bptrzH = 3,5-bis(pyridin-2-yl)-H-1,2,4-triazole) has been prepared and characterized its electronic spectral and magnetic properties. This salt is paramagnetic with magnetic moment, μs, being 1.77–1.78 BM at 293 K, but decreased significantly with decreasing temperature to be 0.60–0.63 BM at 90 K, indicating antiferromagnetic nature. This is associated with Cu–Cu magnetic interactions at low temperatures, and suggests that the salt adopt an octahedrally polymeric structure. The electronic spectrum of this salt reveals a strong ligand field band centered at about 13,000 cm–1 and a very strong charge transfer absorption at about 23,000–24,000 cm–1. The spectrum is better resolved at lower temperature and this is parallel to the slight change in color from yellowish-green at room temperature to bright green at low temperature (90 K). The powder XRD of this complex was refined by Le Bail method of Rietica program and found to be fit as triclinic symmetry of spa...
Virtual reality (VR) laboratory is great potential for education. It is recognized as a technological advance that can facilitate a learning process through the development of highly realistic 3D visualization. Using VR laboratory in... more
Virtual reality (VR) laboratory is great potential for education. It is recognized as a technological advance that can facilitate a learning process through the development of highly realistic 3D visualization. Using VR laboratory in teaching and learning makes it possible to manipulate objects in the virtual scene in a manner similar to the real world. Virtual reality laboratory was developed to enhance the students’ critical thinking skills. A Research and Development (R & D) method with a post-test design was used in the research. The subjects included the students who were enrolled at Senior High School in Yogyakarta, Indonesia with a total of 96 grade 10th students. The samples divided into three classes, namely EC-1 with virtual reality laboratory, EC-2 with virtual reality and real laboratory, and CC with real laboratory while the quality VR was applied to chemistry teachers. The findings of this research reveal that the quality of VR laboratory integrated hybrid learning was...
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The complex containing Ni(II)-2,2’-bipyridin (bipy)-trifluoroacetate (TFA) was prepared by direct interaction of the corresponding precursors in an aqueous solution. AAS measurement for metal content, TGA-DTA analysis and electrical... more
The complex containing Ni(II)-2,2’-bipyridin (bipy)-trifluoroacetate (TFA) was prepared by direct interaction of the corresponding precursors in an aqueous solution. AAS measurement for metal content, TGA-DTA analysis and electrical conductance suggest the ionic complex of [Ni(bipy)3](CF3COO)2·6H2O. The magnetic moment of 3.13–3.17 BM indicates the paramagnetism corresponding to two unpaired electrons which is clearly higher than that of the spin only value (2.87 BM), and commonly observed due to the spin-orbit coupling in Ni(II). UV-Vis spectral property revealed the first two main ligand field bands centered at about 14200 and 18650 cm–1, which are attributed to the spin-allowed transition, 3A2g→3T2g and 3A2g→3T1g(F), respectively. The expected third band at higher energy seems to appear as a shoulder at 26500 cm–1 (378 nm), as it is masked by a strong intensity of charge transfer band centered at 31050 cm–1. The infrared spectrum exhibits mode of vibrations of the functional grou...
Program pengabdian pada masyarakat (PPM) ini bertujuan untuk (1) mengidentifikasi miskonsepsi yang dialami guru pada materi kimia SMA yang berhubungan dengan kimia anorganik dan kimia fisik, dan (2) memberikan pendampingan untuk... more
Program pengabdian pada masyarakat (PPM) ini bertujuan untuk (1) mengidentifikasi miskonsepsi yang dialami guru pada materi kimia SMA yang berhubungan dengan kimia anorganik dan kimia fisik, dan (2) memberikan pendampingan untuk meningkatkan penguasaan materi sesuai modul guru pembelajar bagi anggota MGMP kimia Kabupaten Sleman.Kegiatan dilakukan selama 3 kali pertemuan. Pertemuan pertama di SMAN 1 Pakem, dihadiri 24 orang, membahas Sifat Koligatif Larutan dan menyusun Instrumen Penilaian. Pertemuan kedua di SMAN 2 Sleman, dihadiri 27 orang, membahas Penelitian Tindakan Kelas, Laju Reaksi, Termokimia, dan Elektrolisis. Pertemuan ketiga di SMAN 1 Seyegan, dihadiri 24 orang, membahas Teori Atom dan Ikatan Kimia. Kesimpulan daripada kegiatan ini, adalah (1) beberapa guru masih banyak mengalami miskonsepsi dalam pembahasan materi: Laju Reaksi, Termokimia, Elektrolisis, Sifat Koligatif Larutan, dan Bilangan Kuantum dan (2) Modul Guru Pembelajar yang perlu dipahami kembali oleh para gu...
Titanium oxides are wellknown semiconductor and have been studied intensively in term of their physical and chemical properties, and also the applications. The oxides have been modified in many ways to improve the catalitic capability.... more
Titanium oxides are wellknown semiconductor and have been studied intensively in term of their physical and chemical properties, and also the applications. The oxides have been modified in many ways to improve the catalitic capability. Nitrogen has been doped and dyes have been introduced into TiO2. N-TiO2/PbS nanocomposite has been synthesized using successive ionic layer adsorption and reaction (SILAR) method, by which ITO glass layered with N-TiO2 was immersed several cycles in a homogenous mixture of Pb(CH3COO)2 and (NH4)2 S. The combination method of XRD, UV-Vis, and SEM have been used to characterize the samples. It is confirmed that N-TiO2/PbS exists in the samples. The particle size of PbS is about 6-8 nm. The UV-Vis study reveals that the Eg1 of N-TiO2/PbS is lower than that of Eg of N-TiO2 itself, and the Eg2 ie. about 1.62 eV.
The N-doped TiO2/CdS nanocomposite films have been prepared through a successive ionic layer adsorption and reaction (SILAR) method on the N-doped TiO2 thin films with cadmium nitrate as Cd source and sodium sulphide as S precursor. The... more
The N-doped TiO2/CdS nanocomposite films have been prepared through a successive ionic layer adsorption and reaction (SILAR) method on the N-doped TiO2 thin films with cadmium nitrate as Cd source and sodium sulphide as S precursor. The SILAR cycle was varied to study the CdS layer formation and its influence to the properties of resulted nanocomposite, i.e. 1, 5, 10, 25, and 50 cycles, respectively. The resulting materials were characterized using X-Ray Diffraction (XRD), UV/Vis Spectroscopy, and Scanning Electron Microscopy (SEM). The result showed that the higher SILAR cycle resulted in a smaller CdS crystallite size and a higher band gap energy. The higher SILAR cycle was also provided the more intense response in visible light area. The prepared N-doped TiO2/CdS nanocomposite films were then applied in the quantum dots-sensitized solar cells (QDSSC) system. The solar cells performa test showed that there is an optimum cycle which resulting in a highest power conversion. The qua...
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The powder complex of tris(phenanthroline)cobalt(II) trifluoroacetate (TFA) has been prepared by interaction of cobalt(II) nitrate, phenanthroline (phen) in aqueous solution with drops of ethanol, and an excess of saturated aqueous... more
The powder complex of tris(phenanthroline)cobalt(II) trifluoroacetate (TFA) has been prepared by interaction of cobalt(II) nitrate, phenanthroline (phen) in aqueous solution with drops of ethanol, and an excess of saturated aqueous solution of sodium trifluoroacetate, whereupon the yellowish powder was produced. AAS measurment for the metal content, equivalent conductance (1:2), and TGA-DTA of the powder suggest the corresponding formula of [Co(phen)3](TFA)2.5H2O. The efffective magnetic moment of 4.9 BM indicates the high-spin nature of this complex which corresponds to three unpaired electrons in the electronic configuration of Co(II) with significantly higher than the spin only value due to the orbital contribution. UV-Vis spectrum of the complex reveals the d-d spin-allowed transition bands as well as the MLCT and intraligand band. The estimating transition energy ratio of 2.04 for ν2/ν1, is clearly in the range for octahedral configuration. The infrared spectral property indica...
A low-cost process for the depolymerization of polyethylene terephthalate (PET) was investigated in this work by the development of catalysts derived from food wastes for the glycolysis reaction of post-consumable waste of drinking... more
A low-cost process for the depolymerization of polyethylene terephthalate (PET) was investigated in this work by the development of catalysts derived from food wastes for the glycolysis reaction of post-consumable waste of drinking bottles. Bis (2-hydroxyethyl) terephthalate (BHET) is obtained as a product from the glycolysis of polyethylene terephthalate (PET). Calcium oxide (CaO) catalysts derived from shells were used in this reaction. The yield of bis (2-hydroxyethyl) terephthalate (BHET) was obtained and the purity of BHET was confirmed by NMR spectroscopy.
This study aimed to determine (1) the readiness of teacher in applying ICT of science learning, (2) the level according to the application of ICT in the implementation of science learning, (3) the level of completeness of learners after... more
This study aimed to determine (1) the readiness of teacher in applying ICT of science learning, (2) the level according to the application of ICT in the implementation of science learning, (3) the level of completeness of learners after applying ICT in science learning. This evaluation research use the Countenance Stake model that are Antencedent (input), Transaction (process), and Outcomes (output). Respondents involved in this study were Science teachers and students in Junior High School in Yogyakarta that consists of SMPN 5, SMPN 8, SMPN 15, and SMP Pangudi Luhur 1 Yogyakarta.Data collection techniques using purposive sampling using the instrument observation sheets, questionnaires teachers, questionnaires learners interview guidelines and checklist documents RPP. Data were analyzed using a quantitative approach to the t-score, anda qualitative approach descriptively.The results of this study are (1) the preparation of teachers in applying ICT is still not optimal. (2) the suita...
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Penelitian ini bertujuan untuk: (1) mengembangkan multimedia berbasis masalah dengan materi redoks, (2) menganalisis kualitas multimedia berbasis masalah, serta (3) menguji keefektifan multimedia berbasis masalah dalam meningkatkan... more
Penelitian ini bertujuan untuk: (1) mengembangkan multimedia berbasis masalah dengan materi redoks, (2) menganalisis kualitas multimedia berbasis masalah, serta (3) menguji keefektifan multimedia berbasis masalah dalam meningkatkan motivasi belajar dan kemampuan berpikir kritis peserta didik. Penelitian ini termasuk dalam penelitian dan pengembangan berdasarkan model Borg & Gall. Subjek uji coba dalam penelitian ini meliputi peserta didik kelas X SMA Negeri 6 Yogyakarta. Data dikumpulkan melalui angket untuk validasi media, lembar observasi keterlaksanaan pembelajaran, lembar observasi motivasi belajar, angket motivasi belajar, dan tes kemampuan berpikir kritis. Hasil penelitian menunjukkan bahwa (1) pengembangan multimedia berbasis masalah materi redoks dilaksanakan sesuai dengan prosedur pengembangan, (2) secara umum kualitas multimedia berbasis masalah termasuk dalam kategori sangat baik, dan (3) multimedia berbasis masalah efektif untuk meningkatkan motivasi belajar dan kemampua...
Abstrak Senyawa kompleks [Fe(trzH) 2 (trz)][CF 3 SO 3 ] . H 2 O (trzH = 1,2,4-triazola, dan trz = triazolato, yaitu anionik 1,2,4-triazola terdeprotonasi) telah berhasil diisolasi sebagai serbuk halus berwarna putih. Sifat magnetik,... more
Abstrak Senyawa kompleks [Fe(trzH) 2 (trz)][CF 3 SO 3 ] . H 2 O (trzH = 1,2,4-triazola, dan trz = triazolato, yaitu anionik 1,2,4-triazola terdeprotonasi) telah berhasil diisolasi sebagai serbuk halus berwarna putih. Sifat magnetik, spektrum Mössbauer dan spektrum elektroniknya bergantung pada temperatur dan mengungkap bahwa garam ini menunjukkan perilaku transisi keadaan spin termal, singlet -1 A 1g (l.s) quintet -5 T 2g (h.s), dalam besi(II). Transisi bersifat agak tajam tidak tuntas hingga ~ 89 K, dan tanpa menunjukkan gejala histeresis. Pada temperatur kamar spektrum elektronik menunjukkan pita medan ligan spin tinggi yang terbelah menjadi dua pada sekitar 11000 cm -1 dan 13000 cm -1 . Pada temperatur rendah, intensitas pita medan ligan spin tinggi menurun dengan jelas, dan pita medan ligan spin rendah yang sangat kuat muncul pada sekitar 18500 cm -1 . Perubahan pola spektrum elektronik ini diasosiasikan dengan sifat termokromik dari putih pada temperatur kamar menjadi violet pa...
The powder complex of tris(bipyridine)cobalt(II) trifluoromethanesulfonate octahydrate has been synthesized by direct interaction of the corresponding aqueous solutions (and drops of ethanol) of cobalt(II) nitrate, bipyridine, and... more
The powder complex of tris(bipyridine)cobalt(II) trifluoromethanesulfonate octahydrate has been synthesized by direct interaction of the corresponding aqueous solutions (and drops of ethanol) of cobalt(II) nitrate, bipyridine, and potassium triflate. The yellow-orange powder produced was filtered off and allowed to dry on an aeration for characterization. AAS measurement showed the content of metal to be 6.06%, corresponding to the theoretical value of 6.06% in [Co(bipy)3](CF3SO3)2.8H2O. The analysis of conductance producing the charge ratio of cation to anion to be 2:1, confirms the formula. The magnetic moment, µeff, of this complex which was to be 4.5-4.9 BM, indicates that the complex is paramagnetic corresponding to the three unpaired electrons with a significantly orbital contribution. UV-Vis spectrum of the complex reveals the first band observed at about 11100 cm–1, which is associated with the spin-allowed transition, 4T1g → 4T2g. A distinct shoulder at only about 16100 cm–...