|
|
| |
| Articles
by
M. Chakraborty |
Total Records (
3 ) for
M. Chakraborty |
|
 |
| |
|
| |
R. A. Lal
,
S. Choudhury
,
A. Ahmed
,
M. Chakraborty
,
R. Borthakur
and
A. Kumar
|
| |
The mononuclear nickel(II) complex [Ni(H2slox)(H2O)3]
(1) and polymeric dinuclear complexes [Ni2(slox)(A4)]
{A = H2O (2), py (3), 2-pic (4), 3-pic (5)
and 4-pic (6)} and the discrete binuclear complexes [Ni2(slox)(NN)3]
{NN = bpy (7) and phen (8)} have been synthesized from disalicylaldehyde
oxaloyldihydrazone (H4slox) in methanol. All of the complexes are nonelectrolytes.
Complexes 1, 7, and 8 are paramagnetic while binuclear 2-6
possess anomalously low μeff value, indicating considerable
metal-metal interaction. Discrete binuclear 7 and 8 have no interaction
between the two nickel(II) ions. The anomalously low magnetic moment values in
2-6 are explained as metal-metal interaction via phenoxide bridge.
Such metal-metal interactions are less in 7 and 8 due to coordination
of bipyridine and phenanthroline molecules which do not allow phenoxide bridging.
The dihydrazone coordinates to the metal center as a dibasic tridentate ligand
in keto-enol form in staggered configuration in 1, while in the remaining
complexes the dihydrazone is tetrabasic hexadentate in enol form in anticis configuration.
The metal center has a tetragonally distorted octahedral stereochemistry. |
|
| |
|
| |
R. A. Lal
,
M. Chakraborty
,
O. B. Chanua
,
S. Choudhury
,
R. Borthakur
,
S. Copperfield
and
A. Kumar
|
| |
Monometallic zinc(II) and nickel(II) complexes, [Zn(H2nsh)(H2O)] (1) and [Ni(H2nsh)(H2O)2] (2), have been synthesized in methanol by template method from bis(2-hydroxy-1-naphthaldehyde)succinoyldihydrazone (H4nsh). Reaction of monometallic complexes with alternate metal(II) acetates as a transmetallator in 1 : 3 molar ratio resulted in the formation of heterobimetallic complexes [NiZn(nsh)(A)3] and [ZnNi(nsh)(A')2] (A = H2O (3), py (4), 2-pic (5), 3-pic (6), 4-pic (7)), (A' = H2O (8), py (9), 2-pic (10), 3-pic (11), and 4-pic (12)). The complexes have been characterized by elemental analyzes, mass spectra, molar conductance, magnetic moments, electronic, EPR, and IR spectroscopies. All of the complexes are non-electrolytes. Monometallic zinc(II) is diamagnetic while monometallic nickel(II) complex and all heterobimetallic complexes are paramagnetic. The metal centers in heterobimetallic complexes are tethered by dihydrazone and naphthoxo bridging. Zinc(II) is square pyramidal; nickel(II) is six-coordinate distorted octahedral except [ZnNi(nsh)(A)2], in which nickel(II) has square-pyramidal geometry. The displacement of metal center in monometallic complexes by metal ion has been observed in the resulting heterobimetallic complexes. |
|
|
| |
|
| |
A.K. Hira
,
M. Y. Ali
,
M. Chakraborty
,
M. A. Islam
and
M.R. Zaman
|
| |
Proximate components, effect of water-hyacinth leaves (WHL), digestibility of different nutrients of WHL and its nutritive value were determined in the Animal Nutrition Laboratory, Bangladesh Agricultural University, Bangladesh to utilize WHL as feed for goat. Twelve Black Bengal goats of similar age, size and sex were divided into 4 groups having 3 goats in each and fed diets; A (100% Dhal grass- DG) to I , B (75% DG+25% WHL) to II, C (50% DG+50% WHL) to III, and D (100% WHL) to group IV up to 60 days. All the goats were provided 200g-concentrate mixture every day. Goats of group IV were used to determine the digestibility of various nutrients in water-hyacinth leaves. Water-hyacinth leaves contained higher percentage of crude protein, nitrogen free extract and organic matter, and lower percent of crude fibre than Dhal grass. Body weight gain, feed intake and feed conversion efficiency were not significant among the groups. Daily weight gain was 29, 27, 23, and 17g in group I, II, III and IV respectively. Feed conversion efficiency was 16.19, 17.99,18.26 and 24.27 in group I, II, III and IV respectively. Daily dry matter intake in group I, II, III and IV were 0.47, 0.49, 0.42 and 0.42 kg respectively. Average COD of dry matter, crude fibre, ether extract and nitrogen free extract in water-hyacinth leaves were 58.39, 65.38, 59.97, 60.09 and 48.97% respectively. Average digestible nutrients; DCP, DCF, DEE, DNFE and TDN of water-hyacinth leaves were 11.81, 13.60, 2.28, 14.98 and 45.54% respectively. |
|
|
|
|
| |
|
