A set of pentacoordinated dimethyltin(IV) complexes of flexible N‐protected amino acids and fluorinated β‐diketone/β‐diketones was screened for their antibacterial activity against Pseudomonas aeruginosa, Staphylococcus aureus and Streptomyces griseus. These pentacoordinated complexes of the type Me2SnAB (where : R = CH(CH3)C2H5, A1H; CH2CH(CH3)2, A2H; CH(CH3)2, A3H; CH2C6H5, A4H; and BH = R'C(O)CH2C(O)R″: R′ = C6H5, R″ = CF3, B1H; R′ = R″ = CH3, B2H; R′ = C6H5, R″ = CH3, B3H; R′ = R″ = C6H5, B4H) were generated by the reactions of dimethyltin(IV) dichloride with sodium salts of flexible N‐protected amino acids (ANa) and fluorinated β‐diketone/β‐diketones (BNa) in 1:1:1 molar ratio in refluxing dry benzene solution. Plausible structures of these complexes were elucidated on the basis of physicochemical and spectral studies. 119Sn NMR spectral data revealed the presence of pentacoordinated tin centres in these dimethyltin(IV) complexes.

The effect of fluorinated/non-fluorinated β-diketones and side-chain branching of N-protected amino acids on the antibacterial potential of new heptacoordinated monobutyltin(IV) complexes was investigated. New heptacoordinated monobutyltin(IV) complexes having the general formulae BuSn(A) 2 B and BuSnAA 2 H; and BH = R'COCH 2 COR″ (βdiketones), R′ = R″ = -CH 3 : B 1 H; R′ = -CH 3 , R″ = -C 6 H 5 : B 2 H; R′ = -CF 3 , R ″ = -C 6 H 5 : B 3 H] were synthesized. Complexes BuSn(A) 2 B and BuSnA(B) 2 were generated by the reaction of sodium salts of the ligands AH and BH with BuSnCl 3 in 2:1:1 and 1:2:1 molar ratios, respectively. These newly generated complexes were characterized in physicochemical and spectroscopic studies. These complexes contain heptacoordinated tin centres as revealed by 119 Sn NMR chemical shift values. Some of the newly generated complexes and their corresponding ligands were screened for their antibacterial activity to study the structure-activity relationship.

Several new monobutyltin(IV) derivatives containing both oximes and N-protected amino acids have been generated. The compounds having the general formulae BuSn[(L) 2 A], where LH = cyclohexanoneoxime, acetophenoneoxime and AH = C(O)C 6 H 4 C(O)NCHRCOOH (where R = -CH(CH 3 ) 2 , -CH(CH 3 )CH 2 CH 3 , -CH 2 C 6 H 5 ), and BuSn[L(A) 2 ], where LH = cyclohexanoneoxime, acetophenoneoxime and AH = C(O)C 6 H 4 C(O)NCHRCOOH (where R = -CH(CH 3 ) 2 , -CH(CH 3 )CH 2 CH 3 , -CH 2 C 6 H 5 ), 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. 119 Sn NMR spectroscopic data revealed the presence of five and six coordinated tin centers.

No abstract

Dactyloctenium aegyptium (L.) Willd. and D. aristatum Link. are common grass weeds of cultivated fields in many crops. The two grass weed species growing under similar habitat showed characteristic morphological differences of caryopses and seedlings. The identification of weeds at seedling stage may be useful in weed and environment management. Under the light microscopy, features like colour, base, surface, scutellum and hilum of caryopses showed differences between the studied species. D. aegyptium had dark brown caryopses colour, while D. aristatum had grey colour. The base of D. aegyptium was truncate, while D. aristatum had obtuse base. Both species had rugose surface, but in D. aegyptium surface undulations were closely spaced, whereas in D. Aristatum they were widely spaced. Similarly seedlings were found distinct with respect to coleoptile shape and size, first leaf sheath surface and first leaf blade shape and surface. D. aegyptium had oblong coleoptile, whereas it was obovate in D. aristatum. The leaf sheath and leaf blade were recorded glabrous and hairy in D. aegyptium and in D. aristatum respectively. Both species showed remarkable differentiations in their characters, thus indicating that the morphological attributes of caryopses and seedling can be exploited taxonomically and for crop and weed management.