Showing papers by "Karna Wijaya published in 2002"

Polysulfonylamine, CLIII [1]. Schwache Wasserstoffbrücken mit aktivierten Methyldonoren: Kristallstrukturen von Cholinium-, Betainium- und Dimethyl[2-(dimethylamino)ethyl]ammonium-dimesylamid Polysulfonylamines, CLIII [1]. Weak Hydrogen Bonding with Activated Methyl Donors: Crystal Structures of Cholinium, Betainium and Dimethyl[2-(dimethylamino)ethyl]ammonium-dimesylamide

Abstract: In order to study weak hydrogen bonds originating from inductively activated C(sp³)-H donor groups, low-temperature X-ray structures are reported for three onium salts of general formula BH⁺(MeSO₂)₂N-, where BH⁺ is Me₃N⁺CH₂CH₂OH (1; orthorhombic, space group P2₁2₁2₁, Z′ = 1), Me₃N⁺CH₂C(O)OH (2; orthorhombic, P2₁2₁2₁, Z′ = 1), or Me₂HN⁺CH₂CH₂NMe₂ (3; monoclinic, P2₁/c, Z′ = 1). The asymmetric units consist of cationanion pairs assembled by an O-H···O=S hydrogen bond in 1, an O-H···N- bond in 2, and an N⁺-H ··· N⁻ bond in 3. The packings display a plethora of short interionic C(sp³)-H···O/N contacts that are geometrically consistent with weak hydrogen bonding; those taken into consideration have normalized parameters d(H ··· O) ≤ 269 pm, d(H···N) ≤ 257 pm and θ(C-H···O/N) ≥ 127°. The roles of the weak hydrogen bonds are as follows: In structures 1 and 3, the anions are associated into corrugated layers, which intercalate catemers of cations (1) or stacks of discrete cations (3), whereas structure 2 involves cation catemers surrounded by four anion catemers and vice versa; moreover, all cations are linked to adjacent anions by several weak hydrogen bonds (and to one anion in particular by the strong H bond). Among the cation-anion interactions, the N⁺(CH₂-H···)₃O tripod pattern arising in 1 and 2 is of special interest.

Polysulfonylamine, CLIII [1]. Schwache Wasserstoffbrücken mit aktivierten Methyldonoren: Kristallstrukturen von Cholinium-, Betainium- und Dimethyl[2-(dimethylamino)ethyl]ammonium-dimesylamid

Abstract: In order to study weak hydrogen bonds originating from inductively activated C(sp 3 )-H donor groups, low-temperature X-ray structures are reported for three onium salts of general formula BH + (MeSO 2 ) 2 N - , where BH + is Me 3 N + CH 2 CH 2 OH (1; orthorhombic, space group P2 1 2 1 2 1 , Z' = 1), Me 3 N + CH 2 C(O)OH (2; orthorhombic, P2 1 2 1 2 1 , Z' = 1), or Me 2 HN + CH 2 CH 2 NMe 2 (3; monoclinic, P2 1 /c, Z' = 1). The asymmetric units consist of cation-anion pairs assembled by an O-H...O=S hydrogen bond in 1, an O-H...N- bond in 2, and an N + -H...N - bond in 3. The packings display a plethora of short interionic C(sp 3 )-H...O/N contacts that are geometrically consistent with weak hydrogen bonding; those taken into consideration have normalized parameters d(H...O) ≤ 269 pm, d(H...N) ≤ 257 pm and θ(C-H...O/N) ≥ 127°. The roles of the weak hydrogen bonds are as follows: In structures 1 and 3, the anions are associated into corrugated layers, which intercalate catemers of cations (1) or stacks of discrete cations (3), whereas structure 2 involves cation catemers surrounded by four anion catemers and vice versa; moreover, all cations are linked to adjacent anions by several weak hydrogen bonds (and to one anion in particular by the strong H bond). Among the cation-anion interactions, the N + (CH 2 -H...) 3 O tripod pattern arising in 1 and 2 is of special interest.

STUDY OF THERMAL AND ACID STABILITY OF BENTONITE CLAY Studi Kestabilan Termal dan Asam Lempung Bentonit

Abstract: 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 O 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 Nabentonites indicated same thermal stability. However, upon acid treatment, Na-bentonite was found relatively stabiler and more resistance then Ca-bentonite.

A robust eight–membered ring motif in the hydrogen-bonded structure of -(phenylamino)pyridinium- di(methanesulfonyl)amidate

Abstract: 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 (-30C) gave a yield of 0.66 g (64%) and crystals suitable for X-ray study (m.p. 150-152C). The single crystal X-ray result showed that the crystal system was trikline with space group P 1 . The crystal structure of the title compound 2-(phenylamino)pyridinium-di(methanesulfonyl)amidate forms a robust antidromic ring motif type . The structure testifies to the persistence of the 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. ) 8 ( R2

Polysulfonylamine, CLIX [1]. Eine Vielfalt supramolekularer Synthone in zwei Molekülkomplexen von Di(4-halogenbenzolsulfonyl)aminen mit Sauerstoffbasen / Polysulfonylamines, CLIX [1]. A Variety of Supramolecular Synthons in Two Molecular Complexes of Di(4-halobenzenesulfonyl)amines with Oxygen Bases

Abstract: Formation pathways and low-temperature crystal structures are reported for the molecular complexes [(DFBSA)₂ ·(Me₂N)₂CO] (1; monoclinic, space group P2₁/c, Z' = 1) and [(DCBSA)₂·Me₂SO]·MeNO₂ (2; triclinic, P1 , Z' = 1), where DFBSA= di(4-fluorobenzenesulfonyl) amine and DCBSA = di(4-chlorobenzenesulfonyl)amine. In both compounds, the aromatic disulfonylamines display extended conformations contrasting with the folded conformations recently described for three lamellar 1:1 complexes of composition (ArSO₂)₂NH·B (B = oxygen base). The components of 1 and 2 are three-dimensionally associated by a multitude of supramolecular synthons comprising a) in 1 and 2 two conventional N-H···O hydrogen bonds accepted by the carbonyl or sulfoxide function, b) in 1 fourteen and in 2 eleven weak C-H···O hydrogen bonds, c) in 1 three close C-H···F contacts, d) in 2 seven C-H···Cl hydrogen bonds, e) in 2 one Cl ··· Cl and two Cl···O interactions, f) in both structures a triad of aromatic rings that are π-stacked in the face-to-face mode. The interhalogen contact in 2 is of the type II, as characterized by C-Cl ··· Cl angles of 161 and 102°.

THE SYNTHESIS OF Cr2O3-PILLARED MONTMORILLONITE (CrPM) AND ITS USAGE FOR HOST MATERIAL OF p-NITROANILINE Sintesis Lempung Terpilar Cr2O3 dan Pemanfaatannya sebagai Inang Senyawa p-nitroanilin

Abstract: 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 pnitroaniline, 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 XRay 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 A, meanwhile the basal spacing of the hydrated Na-montmorillonite was 14,43 A. The specific surface area of the Cr2O3-pillared montmorillonite was 174,308 m 2 /g, whereas p-nitroaniline-Cr2O3-pillared clay (pNA-CrPM) was 133,331641 m 2 /g. This fact indicated that p-nitroaniline has been included into the pore of the Cr2O3-pillared clay. Keyword: montmorillonite, pillared-clay, ion exchange, intercalate.

Quantitative Relationships Between Molecular Structure And Melting Point Of Several Organic Compounds = Hubungan Kuantitatif antara Struktur Molekul dan Titik Leleh dari Berbagai Senyawa Organik

Abstract: Quantitative Structure – Property Relationships (QSPR) analysis of the Melting Point (m.p) of 349 organic compounds using molecular descriptors based on linear regression have been done. The experiment m.p. values were collected from the CRC Hand Book of Chemistry and Physic 81 th [1]. Molecular description of each compound was described in the form of the number of atoms and number of chemical bonding. This study was made in the form of normal melting point (in Kelvin unit) as the linear function of all molecular descriptor. The best equation model was determined by regression multilinear analysis and the result showed that the melting point is linearly correlated with: n(Csek alf), n(Cter alf), n(Csek sik), n(Cter sik), n(Csek arm), n(Cter arm), n(O), n(N), n(F), n(Cl), n(C–C sik), n(C=C arm), n(C1=C2), n(C2=C3), n(C–O), n(C–Br), n(C–I), n(N–H), n(Z), n(ortho), n(meta), n(para), (BM), n(C-H) 2 , n(H x BM) and n(Cprim x BM). The QSPR equation is significant at 95 % level and has statistical parameters: n = 349, r = 0.943, SD = 24.336 and Fexp = 99.326, respectively.

DETERMINATION OF MANY-BODY EFFECT OF (Co(NH3)n) 2+ (n=1-6) COMPLEXES BASE ON AB INITIO CALCULATIONS Penentuan Pengaruh Badan-Banyak pada Kompleks (Co(NH3)n) 2+ (n=1-6) Berdasarkan Perhitungan Ab Initio

Abstract: The computational chemistry calculation to determine the stabilization energy and ligand-ligand repulsion energies of [Co(NH3)n] 2+ system was done by using LANL2DZ basis set for Co 2+ and 6-31G* basis set for NH3 at the level theory of unrestricted Hartree-Fock (UHF). Result from the calculation shows that the larger number of NH3 ligand present in the complex give the effect of the lower average binding energy per ligand molecule, i.e. –503,29 kJ/mol for [Co(NH3)] 2+ and then decrease to –338,025 kJ/mol for octahedral [Co(NH3)6] 2+ complex. A correlation between the number of ligand and the metal ion– ligand bond distance was studied. The result shows that the metal ion-ligand bond distance increases along with the larger number of the ligand. The calculation of average pair interaction energies between Co 2+ and NH3 in [Co(NH3)n] 2+ complexes were done in order to determine the error possibility caused by the neglect of non-additivity contribution. The results indicate that the maximum relative error with respect to the pair potential, %ΔEavpi, is 17,64 % [Co(NH3)6] 2+ complex.

MODELING OF ALKYL SALICYLATE COMPOUNDS AS UV ABSORBER BASED ON ELECTRONIC TRANSITION BY USING SEMIEMPIRICAL QUANTUM MECHANICS ZINDO/s CALCULATION Pemodelan Senyawa Alkil Salisilat sebagai Penyerap Sinar UV Berdasarkan Pendekatan Transisi Elektronik Hasil Perhitungan Mekanika Kuantum Semiempirik ZINDO/s.

Abstract: 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 UVC.

THE INTERACTION OF Co 2+ -AMMONIA MODELLING: THE COMPARATIVE STUDY BETWEEN AB INITIO AND ELECTRON CORRELATION METHODS Pemodelan Interaksi Co 2+ -Amoniak: Perbandingan antara Metode Ab Initio dan Korelasi Elektron

Abstract: Research on comparison between Hartree-Fock method and electron correlation methods as well as the effect of size of basis sets on representing interaction of Co 2+- NH3 observed from complex energy parameters and optimum geometric parameters have been carried out.The first step is screening basis sets based on charge transfer effect and BSSE value. The selected basis set does not yield charge transfer at 1,4 A < + − 2 Co N r < 8 A, and yield small BSSE value. Electron correlation methods used are Moller-Plesset order 2 (MP2), Moller-Plesset order 3 (MP3), Configuration Interaction, Doubles (CID), dan Configuration Interaction, Singles and Doubles (CISD) whereas the basis set used is the result of the screening. LANL2DZ ECP−6-31G* and LANL2DZ ECP−6-311++G(3df,3pd) basis sets are used with Unrestricted Hartree-Fock (UHF) and Moller-Plesset order 2 (MP2) methods to study the effect of size of basis sets.The result of the research showed that the best basis set is LANL2DZ ECP for Co 2+ and 6-31G* for NH3. The application of electron correlation method and large basis set can increase the quality of interaction representation of Co 2+ - NH3. Moller-Plesset (MP) perturbation method gives larger contribution