Garuda - Garba Rujukan Digital

Article Per Year (5 Year)

p-Index From 2021 - 2026

P-Index

This Author published in this journals

All Journal Indonesian Journal of Chemistry

Karna Wijaya

Chemistry Department, Faculty of Mathematics and Natural Sciences, Universitas Gadjah Mada, Yogyakarta

Author-ID : 3959549

Chemical Engineering, Chemistry & Bioengineering Chemistry

Published : 8 Documents Claim Missing Document

Claim Missing Document

Articles

INTERACTION OF IRON(II) MIXED-LIGAND COMPLEXES WITH DNA: BASE-PAIR SPECIFICITY AND THERMAL DENATURATION STUDIES Mudasir Mudasir; Karna Wijaya; Endang Tri Wahyuni; Hidenari Inoue
Indonesian Journal of Chemistry Vol 4, No 3 (2004)
Publisher : Universitas Gadjah Mada

A research about base-pair specificity of the DNA binding of [Fe(phen)3]2+, [Fe(phen)2(dip)]2+ and [Fe(phen)(dip)2]2+ complexes and the effect of calf-thymus DNA (ct-DNA) binding of these metal complexes on thermal denaturation of ct-DNA has been carried out. This research is intended to evaluate the preferential binding of the complexes to the sequence of DNA (A-T or G-C sequence) and to investigate the binding strength and mode upon their interaction with DNA. Base-pair specificity of the DNA binding of the complexes was determined by comparing the equilibrium binding constant (Kb) of each complex to polysynthetic DNA that contain only A-T or G-C sequence. The Kb value of the interaction was determined by spectrophotometric titration and thermal denaturation temperature (Tm) was determined by monitoring the absorbance of the mixture solution of each complex and ct-DNA at λ =260 nm as temperature was elevated in the range of 25 - 100 oC. Results of the study show that in general all iron(II) complexes studied exhibit a base-pair specificity in their DNA binding to prefer the relatively facile A-T sequence as compared to the G-C one. The thermal denaturation experiments have demonstrated that Fe(phen)3]2+ and [Fe(phen)2(dip)]2+ interact weakly with double helical DNA via electrostatic interaction as indicated by insignificant changes in melting temperature, whereas [Fe(phen)2(dip)]2+ most probably binds to DNA in mixed modes of interaction, i.e.: intercalation and electrostatic interaction. This conclusion is based on the fact that the binding of [Fe(phen)2(dip)]2+ to ct-DNA moderately increase the Tm value of ct- DNA

SYNTHESIS OF IRON OXIDE-MONTMORILLONITE COMPOSITE AND STUDY OF ITS STRUCTURAL STABILITY AGAINTS SULFURIC ACID Karna Wijaya; Eko Sugiharto; Mudasir Mudasir; Iqmal Tahir; Ika Liawati
Indonesian Journal of Chemistry Vol 4, No 1 (2004)
Publisher : Universitas Gadjah Mada

The synthesis and characterization of iron oxide-montmorillonite and its structural stability test with various concentration of sulfuric acid were conducted. Synthesis was performed by treating Na-montmorillonite clay with oligocations of iron, followed by calcinating the intercalation compound of oligocations-montmorillonite at 200oC for 24 hours. Calcined product was then characterized to determine the iron content, basal spacing and its porosities distribution. To test structural stability againts strong acid (i.e. sulfuric acid), the composites were dispersed into solution of sulfuric acid with various concentration, i.e: 1, 2 and 3M for 24 hours.The characterization result, especially from x-ray-diffractometry analysis, demonstrated that modification of montmorillonite using iron (III)oxide produced so called house of card structure as indicated by its broad, low intensity reflection at 2θ = 5-6o. The addition of sulphuric acid into composite resulted in probably the formation of face to face arrangements indicated by the appearance of 001 plane reflection. The acid treatment also caused the decrease in the iron content of the iron oxide-montmorillonite as shown by its neutron activated analysis result. The iron content of iron oxide-montmorillonite before the acid treatment was 32,01% w/w, and after the acid treatment was 14.08% w/w (with sulfuric acid of 1M), 6.05% w/w (sulfuric acid of 2M) and 5,98% w/w (with sulfuric acid of 3M), respectively.In general, the sulphuric acid treatment to the composite did not distore the 001 planes of the montmorillonite.

STUDY OF DOUBLE PROTONS MIGRATION MECHANISM IN SUPRAMOLECULAR STRUCTURES OF ACETIC ACID-WATER AND ACETIC ACID-AMMONIA BY AB INITIO METHOD Karna Wijaya; Iqmal Tahir; Harnowo Harnowo
Indonesian Journal of Chemistry Vol 3, No 2 (2003)
Publisher : Universitas Gadjah Mada

The theoretical study of double protons migration mechanism on acetic acid-water and acetic acid-ammonia associations has been carried out. The research covered determinations the reactant, transition state and product structures. To gain the goal, the research was conducted in three steps, i.e. (i) designing the reactant, transition state and product models, (ii) optimizing of structures, and (iii) calculating of their uncorrected total energy and frequencies with ab initio methods (basis set 6-31G**). All calculations were performed using Hyperchem ver 5.0 for Windows and Gaussian 94W package program. The computational study result showed that the calculated structures were in good agreement with the hypothetical structures.

QSAR STUDY OF FLAVONE / FLAVONOL ANALOGUES AS THE ANTIRADICAL COMPOUNDS BASED ON HANSCH ANALYSIS Iqmal Tahir; Karna Wijaya; Bambang Purwono; Dinni Widianingsih
Indonesian Journal of Chemistry Vol 3, No 1 (2003)
Publisher : Universitas Gadjah Mada

Quantitative Structure-Activity Relationship (QSAR) analysis of substituted flavone / flavonol compounds has been carried out by applying Hansch Analysis using their physicochemical properties as the predictors. The properties i.e. log P, (log P)2, core-core interaction energy (Eint), volume (V), molecular mass (M), dipole moment (μ), heat of formation (ΔHof), binding energy (Ei), total energy (ET), surface area (L), polarizability (α), molar refractivity (RM), hidration energy (EH), electronic energy (Eel) and isolated atomic energy (Eat,is), were obtained on the basis of geometry optimization using PM3 semiempirical method. The QSAR analysis used antiradical activities (% A) as the dependent variable and has been done by applying multilinear regression technique. The result showed that QSAR equations i.e.% A = 77.426 - 67.343 [log P] + 3.160 [(log P)2 + 67.884 [α] + 6.63x10-4 [ Eint] - 5.280 [L] + 1.179 [V] + 0.447 [M] - 11.000 [μ] + 0.093 [Ei] + 3.433 [EH] - 3.44x10-3 [ET](n = 16 ; r2 = 0.987 ; SD = 9.205; Fcal/Ftable = 4.797)

THE SYNTHESIS OF Cr2O3-PILLARED MONTMORILLONITE (CrPM) AND ITS USAGE FOR HOST MATERIAL OF p-NITROANILINE Karna Wijaya; Iqmal Tahir; Ahmad Baikuni
Indonesian Journal of Chemistry Vol 2, No 1 (2002)
Publisher : Universitas Gadjah Mada

The synthesis of Cr2O3-pillared montmorillonite (CrPM) and its usage for host material of p-nitroaniline have been conducted. The Cr2O3-pillared montmorillonite clays was prepared by a direct ion exchange method. First, the polyhydroxychromium as a pillaring spesies was intercalated into the interlayer region of the montmorillonite clays (purified clay in the monocation form), result in a montmorillonite-polyoxychromium intercalation compound. The precursors/pillaring spesies was not stable, hence it must be stabilized by calcination in order to transform the polyoxychromium via dehydration and dehydroxylation processes into Cr2O3. This oxide constituts the so-called pillar that prop the clay layers apart to a relatively large distance. The Cr2O3-pillared clays as a host material was added into ethanol solution saturated with p-nitroaniline, and mixture was stirred for 24 h at room temperature. The Na-montmorillonite, Cr2O3-pillared clay and p-nitroaniline-Cr2O3-pillared clay (pNA-CrPM) were characterized by X-Ray Diffraction (XRD), Gas Sorption Analysis, Infrared Spectroscopy (FTIR) and Activated Neutron Analysis (ANA) methods. The result of research showed that basal spacing (d001) of Cr2O3-pillared montmorillonite (CrPM) was 18,55 Å, meanwhile the basal spacing of the hydrated Na-montmorillonite was 14,43 Å. The specific surface area of the Cr2O3-pillared montmorillonite was 174,308 m2/g, whereas p-nitroaniline-Cr2O3-pillared clay (pNA-CrPM) was 133,331641 m2/g. This fact indicated that p-nitroaniline has been included into the pore of the Cr2O3-pillared clay.

STUDY OF THERMAL AND ACID STABILITY OF BENTONITE CLAY Karna Wijaya; Ani Setyo Pratiwi; Sri Sudiono; Emi Nurahmi
Indonesian Journal of Chemistry Vol 2, No 1 (2002)
Publisher : Universitas Gadjah Mada

The thermal and acid stability of the bentonite clays (Na- and Ca-bentonite) have been tested. The thermal stability testing has been carried out by heating 5 gram of the clays for five hours at 200, 300 and 500 °C respectively, meanwhile acid stability testing was performed by immersing 5 gram clays into 100 mL sulphuric acid 1M, 2M and 3M for 24 hours. The tested clays, then were characterized by means of X-Ray difractometry and IR-spectroscopy methods. The characterization results showed that upon heating, both Ca- and Na-bentonites indicated same thermal stability. However, upon acid treatment, Na-bentonite was found relatively stabiler and more resistance then Ca-bentonite.

MODELING OF ALKYL SALICYLATE COMPOUNDS AS UV ABSORBER BASED ON ELECTRONIC TRANSITION BY USING SEMIEMPIRICAL QUANTUM MECHANICS ZINDO/s CALCULATION Iqmal Tahir; Karna Wijaya; Titik Subarni
Indonesian Journal of Chemistry Vol 2, No 1 (2002)
Publisher : Universitas Gadjah Mada

Modeling of several alkyl salicylates based on electronic transition by using semiempriical mechanical quantum ZINDO/s calculation has been done. Object of these research were assumed only alkyl salicylates of C4 (butyl) until C8 (octyl) homologue with 4-7 example structures of each homologue. All of the computation have been performed using quantum chemistry - package software Hyperchem 6.0. The research covered about drawing each of the structure, geometry optimization using semiempirical AM1 algorithm and followed with single point calculation using semiempirical ZINDO/s technique. ZINDO/s calculations used a defined criteria that is singly excited - Configuration Interaction (CI), gap of HOMO-LUMO energy transition was 2 and degeneracy level was 3. Analysis of the theoretical spectra was focused in the UV-B (290-320 nm) and UV-C (200-290 nm) area. The result showed that modeling of the compound can be used for predicting the type of UV protection activity depending with the electronic transition in the UV area. Modification of the alkyl homologue relatively did not change the value of wavelength absorbtion to indicate the UV protection activity. Alkyl salicylate compounds were predicted as UV-C sunscreen or relatively the compounds have protection effect for UV-C.

A ROBUST EIGHT–MEMBERED RING MOTIF IN THE HYDROGEN-BONDED STRUCTURE OF -(PHENYLAMINO)PYRIDINIUM- DI(METHANESULFONYL)AMIDATE Karna Wijaya; Iqmal Tahir; Armand Blaschette; Oliver Mours; Peter G Jones
Indonesian Journal of Chemistry Vol 2, No 1 (2002)
Publisher : Universitas Gadjah Mada

The compound was prepared by dissolving 2-(phenylamino)pyridine (0.52 g ; 3.0 mmol) and di(methanesulfonyl)amine (0.51 g; 3.0 mmol) in 5 mL methanol. Slow partial evaporation of the solvent at low tempertaure (-30 oC) gave a yield of 0.66 g (64%) and crystals suitable for X-ray study (m.p. 150-152 oC). The single crystal X-ray result showed that the crystal system was trikline with space group P1. The crystal structure of the title compound 2-(phenylamino)pyridinium-di(methane-sulfonyl)amidate forms a robust antidromic ring motif type R228. The structure testifies to the persistence of the R228 in question, which was previously detected as a robust supramolecular synthon in 2-aminopyridinium di(benzenesulfonyl)amidate and in a series of onium di(methane-sulfonyl)amidates.

Co-Authors Ahmad Baikuni Ani Setyo Pratiwi Armand Blaschette Bambang Purwono Dinni Widianingsih Eko Sugiharto Emi Nurahmi Endang Tri Wahyuni Harnowo Harnowo Hidenari Inoue Ika Liawati Iqmal Tahir Iqmal Tahir Mudasir Mudasir Oliver Mours Peter G Jones Sri Sudiono Titik Subarni

Title

Found 8 Documents
Search

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Title Search

Found 8 Documents Search

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Abstract

Title

Found 8 Documents
Search