Asha Jain

Preparation, Structural Chemistry and Spectroscopic (IR, 1H & 13C) Characterization of Certain Lead(II) Complexes of Sterically Demanding Heterocyclic β-Diketones. X-Ray Crystal Structure of Bis[4-Acetyl-2,4- Dihydro-5-Methyl-2-Phenyl-3H-Pyrazol-3-Onato) Lead(II), C24H22N4O4Pb

Some new lead(II) complexes of bulky heterocyclic ß-diketones having composition Pb(II) [ R C O C : C O N ( C 6 H 5 ) N : C C H 3 ] 2 (where R = -CH 3 , -C 2 H 5 , -C 6 H 5 and -p-ClC6H4) were synthesised by the interaction of lead isopropoxide with the corresponding ligands in 1:2 molar ratio in refluxing benzene solution. The structural elucidation of these derivatives is based upon physico-chemical and spectral studies. The crystal structure of one of the representative complex of composition Pb(II)

STRUCTURAL AND STEREOCHEMICAL CONSIDERATIONS OF BIS(4-ACETYL-2,4-DIHYDRO-5-METHYL-2-PHENYL-3H-PYRAZOL-3-ONATO)DIMETHYLTIN(IV) BASED UPON SINGLE CRYSTAL X-RAY ANALYSIS

The structural features and stereochemical aspects of the title compound, Me2Sn[CH3COC: CON(C6H5)N:CCH3]2, have been established by a single crystal X-ray study. The geometry around the tin atom is distorted octahedral with methyl groups approximately trans to each other. The heterocyclic ß-diketonate ligand binds the central tin atom through both the oxygen atoms.

One-Pot Three-Component Condensation Reaction in Water: An Efficient and Improved Procedure for the Synthesis of Pyrimido[2,1-b]benzothiazoles

Industries are constantly in search of efficient and green chemistry protocols for the synthesis of pyrimido [2,1-b]benzothiazoles. One-pot reaction of 2-aminobenzothiazole, active methylene derivatives, and carbonyl compounds expeditiously annulate a pyrimidine ring on the benzothiazole nucleus to yield pyrimido [2,1-b]benzothiazole under microwaves or ultrasonic waves using water as energy transfer medium. The title compounds are easily accessible by various approaches; even waste-free procedures have been developed. The operational simplicity, environmentally friendly conditions, and high yield achieved in a very short reaction time are major benefits that meet the requirements of green production, including saving energy and high efficiency. The results are compared with conventional heating. Structural assignments are based on spectroscopic data.

CERTAIN TRIPHENYLGERMANIUM(IV) COMPLEXES OF STERICALLY CONGESTED HETEROCYCLIC β-DIKETONES: SYNTHETIC AND STRUCTURAL CONSIDERATIONS

Department of Chemistry, University of Rajasthan, Jaipur-302 004, India Abstract Some new triphenylgermanium(IV) complexes of composition, Pn;Ge[RCbCiCON(C6Hs)N:CCH^ (where R = CH3, C2H5, C6HS and p-ClCsH-t) have been synthesised by the interaction of triphenylgermanium (IV) chloride with the sodium salt of sterically congested heterocyclic ß-diketones in a 1:1 molar ratio in dry THF solution. Osmometric molecular weight measurements of these derivatives in chloroform solution reveal their monomeric nature. The plausible structures of these complexes have been proposed with the help of physico-chemical and spectral studies.

Assessment of Toxicity of Some Penta- and Hexacoordinated Organotin(IV) and Tetracoordinated Tin(II) Complexes of Heterocyclic beta-Diketones.

A number of penta- and hexacoordinated organotin(IV) complexes and tetracoordinated tin(II) complexes of compositions Me2SnCl[RCOC:CON(C6H5)N:C⎴CH3] (where R = − CH3, −p−ClC6H4, and −C6H5), Me2Sn[RCOC:CON(C6H5)N:C⎴CH3]2 (where R = −CH3, and −C6H5), and Sn(II) [RCOC:CON(C6H5)N:C⎴CH3]2 (where R = −p−ClC6H4 and −C6H5) were screened for their toxicity against Musca domestica (house fly). In general, organotin(IV) complexes contribute more to the activity than tin(II) complexes.

Synthesis of novel penta and hexa coordinated monobutyltin(IV) derivatives based on oximes and N-protected amino acids

Abstract Several new monobutyltin(IV) derivatives containing both oximes and N-protected amino acids have been generated. The compounds having the general formulae BuSn[(L)2A], where LH=cyclohexanoneoxime, acetophenoneoxime and (where R=-CH(CH3)2, -CH(CH3)CH2CH3, -CH2C6H5), and BuSn[L(A)2], where LH=cyclohexanoneoxime, acetophenoneoxime and (where R=-CH(CH3)2, -CH(CH3)CH2CH3, -CH2C6H5), were generated by the reactions of monobutyltin(IV) trichloride with sodium salts of oximes and N-protected amino acids in 1:2:1 and 1:1:2 molar ratios in dry boiling benzene. Plausible structures of these compounds were suggested based on physico-chemical and spectroscopic studies. 119Sn NMR spectroscopic data revealed the presence of five and six coordinated tin centers.

Some new N-protected amino acid derivatives of phenylboronic acid: preparation, structural chemistry and insight into structural aspects based on spectroscopic studies

Abstract Some new 1,3-dihydro-1,3-dioxo-α-substituted-2H-isoindole-2-acetic acid derivatives of phenylboronic acid of compositions PhBOH[O2CCH(R)C(O)] and PhB[O2CCH (R)(O)]2 [where -CH(R)=-CH2CH2-, R=-CH2C6H5, -CH(CH3)2, and -CH(CH3)C2H5] have been prepared by the reaction of phenylboronic acid with N-protected amino acids in 1:1 and 1:2 molar ratios in dry refluxing benzene. Plausible structures of these newly synthesized N-protected amino acid derivatives of phenylboronic acid have been proposed on the basis of physicochemical and spectroscopic studies. 11B NMR data reveal the presence of tetracoordinated boron centers in these N-protected amino acid derivatives of phenylboronic acid.

Some Zirconium(IV) Complexes of Sterically Constrained Sulfur-Containing Schiff Bases of Heterocyclic β -Diketones: Synthetic Strategy and Structural Investigation Based Upon Spectroscopic Studies

Zirconium(IV) Schiff base chelates having the general formula ZrL(OPr i )2 [where LH 2 = R CH 3 , R = –C 6 H 5 , –C 6 H 4 Cl(p)] were synthesized by the reaction of Zr(OPr i )4.Pr i OH with sterically constrained sulfur-containing Schiff bases of heterocyclic β -diketones in a 1:1 molar ratio in dry refluxing benzene. The complexes ZrL(OPr i ) 2 were used as important precursors for the synthesis of the complexes of the type Zr(L) 2 . The complexes, Zr(L) 2 , were prepared by the interaction of precursor ZrL(OPr i ) 2 with sterically constrained sulfur-containing Schiff bases of heterocyclic β -diketones in a 1:1 molar ratio in dry benzene. The structures of these zirconium(IV) chelates have been discerned with the help of elemental analyses, physicochemical studies, and spectral [IR and NMR ( 1 H and 13 C)] data. A distorted trigonal bipyramidal and a distorted octahedral geometry may be assigned to zirconium(IV) chelates of the types ZrL(OPr i ) 2 and Zr(L) 2 , respectively.

Generation, spectroscopic characterization and antioxidant activity of tetracoordinate and hexacoordinate complexes of diethylgermanium(IV) of relatively sterically undemanding N-protected amino acids and sterically demanding heterocyclic β-diketones containing radical sensitive Ge-O bond

ABSTRACT Two new sets of diethylgermanium(IV) complexes of the types Et2GeA2 and Et2GeB2 have been generated by the reactions of diethylgermanium(IV) dichloride with sodium salts of N-protected amino acids (AH) [where AH = , R = -CH(CH3)C2H5: A1H, R = -CH2CH(CH3)2: A2H, R = -CH(CH3)2: A3H] and with sodium salts of sterically demanding heterocyclic β-diketones (BH) [where BH = , R’ = -C6H5: B1H, R’ = -p-(Cl)C6H4: B2H, R’ = -CH3: B3H, R = -C2H5: B4H], respectively in 1:2 molar ratios in refluxing dry benzene. Plausible structures of these complexes were suggested on the basis of physico-chemical and spectroscopic studies. It is suggested that the complexes of the types Et2GeA2 and Et2GeB2 contain four coordinated and six coordinated germanium centers, respectively. The ligands and organogermanium(IV) complexes were evaluated for their free radical scavenging activity by DPPH method. These compounds/complexes demonstrate potential antioxidant activity. GRAPHICAL ABSTRACT