Jaripa Begum

The preparation, characterization, crystal structure and biological activities of some copper(II) complexes of the 2-benzoylpyridine Schiff bases of S-methyl- and S-benzyldithiocarbazate

The complexes [Cu(NNS)X] (HNNS represents the 2-benzoylpyridine Schiff bases of S-methyl- or S-benzyldithiocarbazate; XCl, Br, NO3) have been prepared and characterized by a variety of physico-chemical techniques. Magnetic and spectral evidence support a square-planar structure for the [Cu(BpSR)X] (BpSR=the benzoylpyridine Schiff bases; RCH3, CH2C6H5; XCl, Br) and [Cu(BpSMe)NO3] complexes and a five-coordinate distorted square-pyramidal structure for the [Cu(BpSBz)NO3] complex. The crystal structures of [Cu(BpSMe)NO3] and [Cu(BpSBz)NO3] have been determined by X-ray diffraction studies. The complex [Cu(BpSMe)NO3] crystallizes in the triclinic space group P1 with a=7.600(3), b=10.5346(2), c=11.564(3) A, α=116.0033(14), β=103.91(3), γ=91.55(3)°, V=798.3(4) A and Z=2. The complex has a distorted square-planar geometry with the copper ion lying in an approximate plane of four coordinating atoms, three of which come from the 2-benzoylpyridine Scniff base of S-methyldithiocarbazate while the fourth coordination site is occupied by an oxygen from the nitrate ligand. The complex, [Co(BpSBz)NO3] crystallizes in the monoclinic space group P21/a with a=9.0124(19), b=18.501(5), c=13.0642(24) A, β=106.377(15)°, V=2089(9) A3 and Z=4. The coordination environment around the copper(II) ion is a distorted square-pyramid with three donor atoms (NNS) coming from the 2-benzoylpyridine Schiff base and the fourth and fifth atoms (oxygen) coming from the bidentade NO3− ion. The antifugal and antibacterial properties of the Schiff bases and their copper(II) complexes have been evaluated against three pathogenic fungi and two bacteria. The Schiff bases and copper(II) complexes display moderate antifungal activities but their activities are less than that of the commercially important antifungal agent nystatin.

Synthesis, characterization and biological activities of some nickel(II) complexes of tridentate NNS ligands formed by condensation of 2-acetyl- and 2-benzoylpyridines with S-alkyldithiocarbazates

SummaryNickel(II) complexes of four tridentate NNS Schiff base ligands, derived by condensing 2-acetyl-and 2-benzoylpyridine with S-methyl- and S-benzoyldithiocarbazate, have been prepared and characterized. The monoligated complexes, [Ni(NNS)X] (NNS = anionic ligand; X = Cl, Br, NCS, I) are diamagnetic and square-planar, whereas the bis-ligand complexes, [Ni(NNS)2] are paramagnetic and tetragonal. The Schiff bases are fungitoxic towards A. solani, F. equisetti and M. phaseolina (approaching the toxicity of the commercial fungicide Nystatin), but the nickel(II) complexes are less fungitoxic than the free ligands.

Studies on the essential oil bearing plants of Bangladesh. Part VI. Composition of the oil of Ocimum gratissimum L.

The composition of the essential oil of Ocimum gratissimum L. obtained from plants originating from Bangladesh and from plants introduced into Bangladesh from India is reported. The oil obtained from plants native of Bangladesh can be classified as thymol-type according to its thymol content (58.2%), while the oil obtained from plants introduced from India can be classified as eugenol/ocimene type according to its content of eugenol (66.5%) and ocimenes (18.9%).

Studies in the Essential Oil Bearing Plants of Bangladesh. Part V. Composition of the Leaf Oils of Eucalyptus citriodora Hook and E. alba Reinw. ex Blume.

Abstract Eucalyptus citriodora and E. alba leaf oils, obtained by hydrodistillation, were analyzed by GC and GC/MS. Thirty-five components were identified in the E. citriodora oil. The main components were citronellal (77.0%), neoisopulegol (7.3%), citronellol (5.9%) and iso(iso)pulegol (4.1%). Fifty-nine components were identified in E. alba oil with the main components being β-pinene (24.0%) and α-pinene (12.9%).

Constituents of the essential oil from leaves and buds of clove (Syzigium caryophyllatum (L.) Alston)

Essential oil obtained by hydrodistillation from fresh leaves and dry buds of Syzigium caryophyllatum were analyzed by gas chromatography mass spectrometer (GC-MS). Thirty eight components were identified in the leaf oil. The main components were eugenol (74.3%), eucalyptol (5.8%), caryophyllene (3.85%) and α-cadinol (2.43%). Thirty one components were identified in bud oil with the main components being eugenol (49.7%), caryophyllene (18.9%), benzene,1-ethyl-3-nitro (11.1%) and benzoic acid,3-(1-methylethyl) (8.9%). The clove oil from Bangladesh was found to be comparable in terms of its eugenol content. It is suggested that clove can be grown as an economically viable crop in Bangladesh.

Volatile constituents of essential oils isolated from different parts of Alpinia calcarata Rosc

The essential oils isolated from different parts of Alpinia calcarata Rosc. growing in Chittagong, Bangladesh, were analyzed by gas chromatography-mass spectrometry (GC-MS). The leaf oil contained 1,8-cineole (28.48%) and camphor (21.40%) as the major constituents. The stem sheath oil had fenchyl acetate (19.16%) and carotol (16.77%) as the major compounds. On the other hand, the root oil showed fenchyl acetate (51.34%) and borneol (11.44%) as the main constituents.

Studies on the Essential Oil Bearing Plants of Bangladesh. Part IV. Composition of the Leaf Oil of Three Cymbopogon species: C. flexuosus (Nees ex Steud.) Wats., C. nardus (L.) Rendle var. confertiflorus (Steud.) N. L. Bor and C. martinii (Roxb.) Wats. var. martinii

Abstract The oils of Cymbopogon martinii(Roxb.) Wats. var. martinii (palmarosa), C. nardus (L.) Rendle var. confertiflorus (Steud.) N. L. Bor and C. flexuosus (Nees ex Steud.) Wats, produced in Bangladesh were subjected to analysis by GC and GC/MS. The oil of C. martinii var. martinii was found to contain geraniol (82.2%) and geranyl acetate (10.1%), while the oil of C. nardus var. confertiflorus also contained geraniol (75.1%) and geranyl acetate (7.6%) as major components. The oil of C. flexuosus contained the expected neral (36.4%) and geranial (50.2%) as major components, while a mutant strain of the same species was found rich in geraniol (38.6%), geranial (8.1%) and methyl eugenol (9.7%).