VOLUME 6, NO1, MAR 1984

Thermolysis of some Nitrogen Ligated Complexes of Transition and non Transition metals

Thermal dissociation of some nitrogen ligated complexes of 2-quanidinobenzimidazole (GMB). - 1,2-dimorpholinoethane (DME) and 1,3­dimorpholinopropane (DMP) ~~ith Ni (11), Cu(II) Zn(II), Cd(I), Hg (II) and Mn(II) have been studied by thermogravimetry and few compounds by differential thermal analysis. The thermal decomposition of SBM, DME and DMP complexes with transition metals was generally obselV<:u occur in two stages. The dissociation sequence observed for GBM complexes was such that the ligand was lost in the second stage of dissociation. However DME and DMP chelates were found to follow entirely different decomposit-ion mechanism. In DMP chelates the ligand was lost in the first stage of dissociation followed by the elimination of halogens. DME compl~xes, unlike DMP chelates, loses part of the ligand, one morpholine moiety, in the fi rst stage and morphol i no-ethane moiety in the second stage of dissociation. The non-transition metal complex of all the three ligands follow the same sequence of decomposition and analysis of Ni(II) complexes are also reported. The react ions found in DTA curves correspond well to those found in the TGA curves.read more

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T ALI ,A WADUD ,H A RASHID ,

Synthesis of Some Triazoles and Thiadiazoles Bearing Phosphorus Substituents

Severa 1 aryl thi osemi ca rbazi des were synthes i zed by condens i ng p-(diphenylphosphino)benzoic acid hydrazide and diphenylphosphinoacetic acid hydrazide with suitable aryl isothiocyanates. Cyclisation of these thiosemi­carbazides with 2N sodium hydroxide afforded 5-substituted phosphino-4-aryl -3-mercapto-s-triazoles. When cyclisation was affected by concentrated sul­phuric acid, 2-arylamino-5-substituted phosphino-l,2,4-thiazoles were obtai­ned.read more

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M A HASSAN ,M EL DEEK ,A I H HASHEM ,S EL HAMSHARY ,

The Reaction of Harmaline with Cyclohexanone Oxalyl Chloride Adduct - A One Step Synthesis of Reserpine Analogues

The reaction of cyclohexanone with oxalylchloride affords the adduct (3). Reaction of (3) with harmaline (1) affords a high yield one step synthesis of the pharmacologically interesting skeletal system(5) which bears the carbon frame-work of reserpine. read more

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S FIRDOUS ,A U RAHMAN ,

Reflectance Spectroscopic and Thermogravimetric Identification of Complexes in the Dehydration of Cu 2+ and Mn 2+ A -zeolites

A series of five samples of Cu. A and only one sample of Mn A-zeolites were prepared and investigated. Diffuse reflectance spectroscopic and thermogravimetric techniques were employed for identi­fication of the species arising from the dynamic vacuum  ehydration of the samples at different temperatures.1. Cu 2iH20)6 (distorted octahederal) Cu H20)4 (square planar) 400  Cu {OX)3 (H20) {tetrahedral  Cu (OX)3 (trigonal). 2+ 2+ 2. Mn 20)6 (Octahedral) 298 K ~ Mn {OX)3 {H20)2 (trigonal bipyramid) Mn (OX)3 (H20) (tetrahederal) 623 K ) Mn{OX)3 (trigonal) (where OX designates an oxygen of the lattice). Jahn-Teller effect is responsible fOh the formation of2+the elongated octahedera 1 (tetragona 1) complex of Cu in hydrated Cu A-zeo 1 ites. 2+ Reflectance spectra of Mn3.5 A were featurless, because the transitions are spin-forbidden, therefore the species are identified mainly by thermogravimetry. No structural collapase was detected, only CU4.9 A gave partial lattice destruction.read more

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S AKBER ,

Equilibrium Studies and Mixed Binuclear Complex Formation of Complexes Obtained From Metal-aminopolycarboxylate and Cyano-Complexes

The equilibriurm constants for mixed binuc1 eM camp 1 ex fG rmGion between certain bivalne transition metal-EDTA complexes and various cyano­ comp 1 exes in aqueous sol ut ion have been obtained from spectrophotometric measurements. The results can be interpreted to obtain the order of strenght of binuclear complex formation with metal (II) which is: Cu» Ni) Co with aminocarboxylate complexes:4_NTA)EDDA 4_HEDTA > E'01~ > PDTA)CDTA2_; and with cyano-complexes; Fe{CN)6>Ru( (CN)6 >Fe(CN)6 ) Fe(CN)5(NO) . read more

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A H KHAN ,W C E HIGGINSON ,SR S MURRAY ,

Oxidation of Pyridine Carboxylic Acid Hydrazides with Active and Ordinary Manganese Dioxide

Oxidation of the three isomeric pyridine carboxylic acid hydrazides with active mangnese dioxide in chloroform has been studied. The parallel reactions with ordinary manganese dioxide were also carried out. Pyridine­2-carboxylic acid hydrazide behaves differently than the other two isomers in these reactions.read more

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R IQBAL ,F MALIK ,

A Total Synthesis of ()-Vincamine and ()-Eburnamonine

A synthesis of vincamine (8) and eburnamonine (9) is reported which involves a new route to the key intermediate (7).read more

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A U RAHMAN ,M SULTANA ,

The Effect of pH and Various Additives on Extinction Coefficients for p-Nitrophenol

The mol a r extinction coeffi ci ents for p-nitropheno 1 at pHs in the region of 8.0-9.2 in the presence and absence of various additives were determined. The data were statistically analysed. The validity and reprodu­ci bil ity of these values were di scussed. The study reveals that pH has a considerable effect on molar extinction coefficient values. These values are however not influenced by such additives like cetyltrimethyl ammonium bromide (CTAB). various strengths of carbonate-bicarbonate buffer and pota­ssium bromide at the same pH.read more

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A E BEG ,

Mamegakinone: A New Narrow Range Acid-Base Indicator

Mamegakinone: A New Narrow Range Acid-Base Indicatorread more

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M R KHAN ,

Synthesis of New Compounds of the Phencyclidine Family from Aromatic Conjugated Ketones

Synthesis of New Compounds of the Phencyclidine Family from Aromatic Conjugated Ketonesread more

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M R DARVICH ,