Papers by Arunashree Panda
Coordination Chemistry Reviews, 2009
Polyhedron, 2003
The reactions of the aromatic nitrogen donor ligands pyridine (py) and 4,4?-bipyridyl (4,4?-bipy)... more The reactions of the aromatic nitrogen donor ligands pyridine (py) and 4,4?-bipyridyl (4,4?-bipy) with the transition metal silylamides M{N(SiMe 3 ) 2 } 2 (M 0/Mn, Fe or Co) were investigated. Treatment of the metal amides with pyridine afforded the bispyridine complexes M{N(SiMe 3 ) 2 }(py) 2 (M 0/Mn, 1a; Fe, 2a; Co, 3a). Distillation or sublimation of 2a or 3a afforded the monopyridine complexes M{N(SiMe 3 ) 2 } 2 (py) (M 0/Fe, 2b; Co, 3b). The addition of pyrazine (prz) to Mn{N(SiMe 3 ) 2 } 2 also yielded the bispyrazine adduct Mn{N(SiMe 3 ) 2 } 2 (prz) 2 , 1b. However, the reaction of 4,4?-bipyridyl with Fe{N(SiMe 3 ) 2 } 2 or Co{N(SiMe 3 ) 2 } 2 afforded the polymeric chain-like complexes {M{N(SiMe 3 ) 2 } 2 (4,4?-bipy)} (M 0/Fe, 4; Co, 5). With the exception of 2b, all complexes were characterized by X-ray crystallography. The complexes 1a, 1b, 2a and 3a displayed monomeric structures and metal geometries that are based on a tetrahedron with interligand angles that deviate markedly from idealized values. Complex 3b was found to have a distorted trigonal planar geometry. In contrast, complexes 4 and 5 displayed polymeric zig-zag chain structures which have four coordinate metal centers connected by 4,4?-bipyridyl ligands. Magnetic studies indicated that complexes 1 Á/3b have high-spin electron configurations and that the paramagnetic centers in 4 and 5 did not interact with each other through the 4,4?bipyridyl ligands. #
Inorganic Chemistry, 2002
Journal of The American Chemical Society, 2005
A sequence of first row transition metal(II) dithiolates M(SAr)(2) (M = Cr(1), Mn(2), Fe(3), Co(4... more A sequence of first row transition metal(II) dithiolates M(SAr)(2) (M = Cr(1), Mn(2), Fe(3), Co(4), Ni(5) and Zn(6); Ar = C(6)H(3)-2,6-(C(6)H(2)-2,4,6-Pr(i)(3))(2)) has been synthesized and characterized. Compounds 1-5 were obtained by the reaction of two equiv of LiSAr with a metal dihalide, whereas 6 was obtained by treatment of ZnMe(2) with 2 equiv of HSAr. They were characterized by spectroscopy, magnetic measurements, and X-ray crystallography. The dithiolates 1, 2, and 4-6 possess linear or nearly linear SMS units with further interactions between M and two ipso carbons from C(6)H(2)-2,4,6-Pr(i)(3) rings. The iron species 3, however, has a bent geometry, two different Fe-S distances, and an interaction between iron and one ipso carbon of a flanking ring. The secondary M-C interactions vary in strength in the sequence Cr(2+) approximately Fe(2+) > Co(2+) approximately Ni(2+) > Mn(2+) approximately Zn(2+) such that the manganese and zinc compounds have essentially two coordination but the chromium and iron complexes are quasi four and three coordinate, respectively. The geometric distortions in the iron species 3 suggested that the structure represents the initial stage of a rearrangement into a sandwich structure involving metal-aryl ring coordination. The bent structure of 3 probably also precludes the observation of free ion magnetism of Fe(2+) recently reported for Fe{C(SiMe(3))(3)}(2). DFT calculations on the model compounds M(SPh)(2) (M = Cr-Ni) support the higher tendency of the iron species to distort its geometry.
Cheminform, 2010
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was e... more ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Chemical Communications, 1998
Synthesis, structure and thiol peroxidase-like antioxidant activity of several diaryl diselenides... more Synthesis, structure and thiol peroxidase-like antioxidant activity of several diaryl diselenides having intramolecularly coordinating amino groups are described; the diselenides having both tertiary amino groups and redox-active ferrocenyl units show excellent peroxidase activity.
Chemical Communications, 2000
ABSTRACT The reaction of the tellurium containing macrocyclic Schiff base 1 with Pd(PhCN)2Cl2 and... more ABSTRACT The reaction of the tellurium containing macrocyclic Schiff base 1 with Pd(PhCN)2Cl2 and NH4PF6 gives the expected cationic complex [PdII1][PF6]2; by contrast the reaction of 1 with Pt(cod)Cl2 proceeds via novel transmetallation to yield an organoplatinum complex.
Coordination Chemistry Reviews, 2009
European Journal of Inorganic Chemistry, 2005
... Arunashree Panda 1 ,; Saija C. Menon 1 ,; Harkesh B. Singh 1 ,; Christopher P. Morley 2 ,; Ro... more ... Arunashree Panda 1 ,; Saija C. Menon 1 ,; Harkesh B. Singh 1 ,; Christopher P. Morley 2 ,; Robert Bachman 3 ,; T. Matthew Cocker 3 ,; Ray J. Butcher 4. Article first published online: 23 MAR 2005. ... Keywords: Macrocycles; Selena-aza macrocycles; Palladium; Nickel; Cobalt. Abstract ...
Chemistry-a European Journal, 1999
Abstract A series of novel low-valent organoselenium compounds stabilized by Se⋅⋅⋅ N intramolecul... more Abstract A series of novel low-valent organoselenium compounds stabilized by Se⋅⋅⋅ N intramolecular interactions (such as the one in the figure) were synthesized, characterized, and examined for Se⋅⋅⋅ N nonbonding interactions. A correlation between Se⋅⋅⋅ N intramolecular distance and 77 Se chemical shift is attempted.
Cheminform, 2010
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was e... more ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Journal of Organometallic Chemistry, 2006
A series of macrocyclic adducts of the 22-and 28-membered selenaaza macrocycles (1 and 2, respect... more A series of macrocyclic adducts of the 22-and 28-membered selenaaza macrocycles (1 and 2, respectively) with different counter anions such as halides, sulfate, perchlorate, phosphate, trifluoroacetate and nitrate has been prepared. The adducts have been characterized by elemental analysis, IR, 1 H NMR, 77 Se NMR and ESI-MS analysis. The 77 Se NMR spectrum of the SO 2À 4 adduct ( ) shows an upfield shift compared to the parent macrocycle. The bromo (5), iodo (6), sulfate (7), trifluroacetate (10) adducts of the 22-membered selenaaza macrocycle and perchlorate (16), trifluroacetate (18) adducts of the 28-membered selenaaza macrocycle have been structurally characterized. The crystal structures show extensive hydrogen bonding networks. The molecular structures of all the compounds show the macrocycle to be fully protonated except the trifluroacetate adduct of the 22-membered macrocycle (10), which is only diprotonated. The binding constants of the neutral 22-membered selenaaza macrocycle towards, fluoride, bromide, iodide and sulfate ion have been determined by the NMR titration method.
Organometallics, 1999
A series of intramolecularly coordinated organochalcogen compounds incorporating the 8-(dimethyla... more A series of intramolecularly coordinated organochalcogen compounds incorporating the 8-(dimethylamino)-1-naphthyl and 2-[(dimethylamino)methyl]phenyl groups has been synthesized. All the compounds were synthesized using the ortholithiation methodology. Insertion of elemental selenium into the Li-C bond of RLi (6) (R ) 8-(dimethylamino)-1naphthyl) afforded the lithium areneselenolate RSeLi (7). Oxidative workup of 7 yielded the yellow diselenide 8 in good yield. Reaction of 8 with a stoichiometric amount of sulfuryl chloride gave the monochloro derivative (9). Controlled bromination of diselenide (8) with bromine in carbon tetrachloride gave the stable selenenyl bromide (10). Compound 8 underwent facile reaction with a stoichiometric amount of iodine to give the corresponding novel monoiodo compound (11) in which selenium is covalently bonded to iodine. Attempts to synthesize the chalcogenides, R 2 E, 12 (E ) Se) and 13 (E ) Te), by the reaction of 6 with Se(dtc) 2 and Te(dtc) 2 (dtc ) diethyldithiacarbamate), respectively, were unsuccessful. The reaction of 6 with Te(dtc) 2 afforded the stable RTe(dtc) (14) instead of the expected telluride R 2 Te (13). In contrast, the reaction of R′Li (17) (R′ ) 2-[(dimethylamino)methyl)phenyl] with Se(dtc) 2 and Te(dtc) 2 afforded the expected selenide R′ 2 Se (18) and telluride R′ 2 Te (19), respectively, in moderate yields. The compounds were characterized by elemental analysis, NMR ( 1 H, 13 C, 77 Se, 125 Te), and mass spectral techniques. The structures of the compounds 9, 11, 14, and 18 were determined by X-ray crystallography. Although N‚‚‚E (E ) Se or Te) nonbonded interactions are present in the solid state in all the derivatives, in solution the pyramidal inversion at the nitrogen center is not blocked, and as a result, the NMe 2 signals are observed as sharp signals in the 1 H NMR spectra.
Inorganica Chimica Acta, 2011
This paper highlights our work to establish a new class of macrocycles based on Schiff base conde... more This paper highlights our work to establish a new class of macrocycles based on Schiff base condensation chemistry. The chemistry of a series of azomethine macrocycles, with selenium/tellurium atoms in o-positions with respect to the C@N bond is discussed. These are the first Schiff base macrocycles to incorporate selenium or tellurium atom in the ring. The strong stabilization of the 10-E-3 (E = Se/Te) structures of these macrocycles by E-N coordination permits the access to these novel macrocycles by [2+2] template-free condensation of bis(aldehyde) with primary diamines. The success of cyclization has been confirmed by the usual methods of IR, NMR and X-ray structural determinations. After a brief discussion of the synthetic methods adopted for these macrocycles, their complexing abilities toward different metal ions are covered. The macrocyclic polyamine ligands, derived by reduction of the corresponding Schiff bases, readily form complexes with a range of metal ions. This allows a comparison of the properties of complexes of these ligands with those derived from the Schiff bases containing the same denticity but having a different flexibility. The selena-and tellura-macrocycles reported by other groups in the field are also included for comparison. Also discussed is the anion binding studies of some of these macrocycles.
Organometallics, 2002
A series of diaryl ditellurides with and without coordinating amino/imino groups are synthesized ... more A series of diaryl ditellurides with and without coordinating amino/imino groups are synthesized by using either the Grignard route or the heteroatom-directed aromatic lithiation route. The chiral ditelluride (R),(R)-bis[2-(4-ethyl-2-oxazolinyl)phenyl] ditelluride is synthesized in an enantiomerically pure form by stereoselective ortho-lithiation. The thiol peroxidase activity of the ditellurides is studied by using H 2 O 2 as a substrate and PhSH as a cosubstrate. The initial rates for the reduction of H 2 O 2 catalyzed by diaryl ditellurides are much higher than those catalyzed by the corresponding diselenides. A comparison of the activities between various diorganyl ditellurides and diselenides shows that the presence of basic amino groups in the close proximity of tellurium enhances the reduction rates and the effect of amino groups on the activity is more pronounced in the case of ditellurides as compared to the corresponding diselenides. On the other hand, a correlation between the strength of Te‚‚‚N intramolecular interactions and thiol peroxidase activity reveals that the strong Te‚‚‚N interactions reduce the thiol peroxidase activity of amino/imino-substituted ditellurides. A plot of Te‚‚‚N distances against 125 Te NMR chemical shifts shows a linear correlation. † Indian Institute of Technology. ‡ Howard University. (1) (a) Budisa, N.; Karnbrock, W.; Steinbacher, S.; Humm, A.; Prade, L.; Neuefeind, T.; Moroder, L.; Huber, R. (3) (a) Cotgreave, I. A.; Moldéus, P.; Engman, L.; Hallberg, A. Biochem. Pharmacol. 1991, 42, 1481. (b) Engman, L.; Stern, D.; Cotgreave, I. A.; Andersson, C.-M. J. Am. Chem. Soc. 1992, 114, 9737. (c) Andersson, C.-M.; Hallberg, A.; Brattsand, R.; Cotgreave, I. A.; Engman, L.; Persson, J. Bioorg. Med. Chem. Lett. 1993, 3, 2553. (d) Andersson, C.-M.; Brattsand, R.; Hallberg, A.; Engman, L.; Persson, J.; Moldéus, P.; Cotgreave, I. A. Free Rad. Res. 1994, 20, 401. (e) Engman, L.; Stern, D.; Pelcmanl, M.; Andersson, C.-M. J. Org. Chem. 1994, 59, 1973. (f) Wieslander, E.; Engman, L.; Svensjö, E.; Erlansson, M.; Johansson, U.; Linden, M.; Andersson, C.-M.; Brattsand, R. Biochem. Pharmacol. 1994, 16, 17. (g) Andersson, C.-M.; Hallberg, A.; Linden, M.; Brattsand, R.; Moldéus, P.; Cotgreave, I. Free Rad. Biol. Med. 1994, 16, 17. (h) Engman, L.; Persson, J.; Vessman, K.; Ekström, M.; Berglund, M.; Andersson, C.-M. Free Rad. Biol. Med. 1995, 19, 441. (i) Vessman, K.; Ekstörm, M.; Berglund, M.; Andersson, C.-M.; Engman, L. J. Org. Chem. 1995, 60, 4461. (j) Engman, L.; Stern, D.; Frisell, H.; Vessman, K.; Berglund, M.; Ek, B.; Andersson, C.-M. Bioorg. Med. Chem. 1995, 3, 1255. (k) Briviba, K.; Tamler, R.; Klotz, L.-O.; Engman, L.; Cotgreave, I. A.; Sies, H. Biochem. Pharmacol. 1998, 55, 817. (l) Kanda, T.; Engman, L.; Cotgreave, I. A.; Powis, G. J. Org. Chem. 1999, 64, 8161. (m) Jacob, C.; Arteel, G. E.; Kanda, T.; Engman, L.; Sies, H. Chem. Res. Toxicol. 2000, 13, 3. (n) Malmström, J.; Jonsson, M.; Cotgreave, I. A.; Hammarström, L.; Sjödin, M.; Engman, L. J. Am. Chem. Soc. 2001, 123, 3434.
Journal of Organometallic Chemistry, 2004
The metal-free condensation of bis(2-formylphenyl) telluride (1) with a series of diamines afford... more The metal-free condensation of bis(2-formylphenyl) telluride (1) with a series of diamines affords macrocyclic tellurium ligands 2–7. Crystals of the protonated macrocycle 8 are monoclinic, space group P2/n with a=10.890(5), b=7.414(4), c=24.334(13) Å, Z=2. The reaction of tellurium containing macrocyclic Schiff base 2 with Pd(C6H5CN)2Cl2 gives the expected 1:1 product [Pd(II) 2] Cl2 (9). Complex 9 was treated with excess
Phosphorus Sulfur and Silicon and The Related Elements, 2001
Abstract Although intramolecularly coordinated organotellurium derivatives have been extensively ... more Abstract Although intramolecularly coordinated organotellurium derivatives have been extensively studied in recent years, the analogous derivatives of selenium have received little attention. We have recently started work on syntheses, structures and reactivity of intramolecularly coordinated organoselenium compounds. The synthesis of these compounds makes extensive use of the ortho-lithiation reaction followed by insertion of selenium into Li-C bond.
Journal of Chemical Sciences, 2000
The application of intramolecular coordination in the isolation of novel diaryl diselenides and t... more The application of intramolecular coordination in the isolation of novel diaryl diselenides and their derivatives, monomeric chalcogenolato complexes of group 12 metals, glutathione peroxidase mimics, hybrid bi-, tri- and multidentate ligands and selenium-containing azamacrocycles is described.
Chemistry-a European Journal, 1999
Abstract A series of novel low-valent organoselenium compounds stabilized by Se⋅⋅⋅ N intramolecul... more Abstract A series of novel low-valent organoselenium compounds stabilized by Se⋅⋅⋅ N intramolecular interactions (such as the one in the figure) were synthesized, characterized, and examined for Se⋅⋅⋅ N nonbonding interactions. A correlation between Se⋅⋅⋅ N intramolecular distance and 77 Se chemical shift is attempted.
Journal of Organometallic Chemistry, 2001
ABSTRACT Bis(o-formylphenyl) selenide (7) was synthesized using the ortholithiation methodology. ... more ABSTRACT Bis(o-formylphenyl) selenide (7) was synthesized using the ortholithiation methodology. The reaction of o-lithiobenzaldehyde acetal (5) with Se(dtc)2 (dtc=diethyldithiacarbamate) afforded bis(o-formylphenyl) selenide acetal (6) in good yield. The key starting material 7 was isolated as pale yellow solid upon refluxing 6 with concentrated HCl. The structure of 7 was solved in the monoclinic space group P2/c with cell constants a=8.0170(6) Å, b=8.4514(6) Å and c=17.5289(12) Å, Z=4. The condensation of 7 with diethylenetriamine yielded the novel macrocyclic ligand [C36H38N6Se2] 8 via metal-free dimerization. Crystals of 8 are monoclinic, space group C2/c with a=18.732(3) Å, b=8.6515(10) Å, c=22.590(3) Å and Z=4. Hydrogenation of macrocycle 8 provided the corresponding saturated tetraazamacrocycle [C36H46N6Se2] (9), protonation of which with HBr afforded [C36H52N6Se2Br6·H2O] (10). The two novel cryptands [C54H54N8Se3] (12) and [C54H54N8Te3] (13) were prepared from the reaction of tris(2-aminoethyl)amine (tren) and the chalcogenides (7) and bis(o-formylphenyl) telluride (11) respectively using cesium ion as the template.
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Papers by Arunashree Panda