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Synthesis, Characterization and Thermal Studies of Niobium(V) Complexes of 2-tert-Butylphenol

Sharma N., Sharma M., Kumari M., Chaudhry S. C.

Polish Journal of Chemistry

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2009

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Vol. 83, nr 7

1265-1276

EN

Complexes of composition [NbCl4(OC6H4C(CH3)3-2)] and [NbCl3(OC6H4C(CH3)3-2)2] have been synthesized from the reaction of niobium pentachloride with equimolar and bimolar amounts of 2-tert-butylphenol in carbon tetrachloride. The complexes have been characterized by physicochemical, IR, 1H and 13C NMR and UV-VIS spectral studies. Based upon these studies, for complexes mononuclear square-pyramidal geometry around niobium has been proposed. Thermal decompositional behaviour of the complexes has been studied by TG, DTA and DSC techniques. From TG data, the kinetic and thermodynamic parameters viz. energy of activation, frequency factor, order of reaction, entropy of activation etc. have been evaluated using Freeman-Carroll, Coats-Redfern and Horowitz-Metzger equations. The reactions of complexes with a variety of nitrogenous bases (L1–L5) (where L1 = imidazole, L2 = benzimidazole, L3 = N-methylimidazole, L4 = 2,2'-bipyridyl and L5 = 1,10-phenanthroline) yielded 1:1 addition compounds authenticated by analytical and IR spectral studies.

2

Synthesis, Characterization and Reactivity of Niobium(V)-2-tert-butylphenoxides

Sharma N., Sharma M., Kumari M., Chaudhry S. C.

Polish Journal of Chemistry

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2009

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Vol. 83, nr 9

1565-1573

EN

The niobium(V)-2-butylphenoxides of composition [NbCl(OC6H4C(CH3)3-2)4] (I) and [Nb(OC6H4C(CH3)3-2)5] (II) have been synthesized by the reaction of NbCl5 with Me3SiOC6H4C(CH3)3-2 in CCl4 and have been characterized by elemental analyses, molar conductance, molecular weight determination, IR, 1H and 13C NMR and UV-VIS spectral studies. The molecular model calculations were performed to visualize the probable geometry acquired by the complexes. Based upon spectral and molecular modelling dynamics, a square-pyramidal geometry around niobium in complexes has been proposed. Thermal behaviour of the complexes has been studied by TG, DTA and DSC techniques. The reactions of [NbCl(OC6H4C(CH3)3-2)4] (I) with chloride ion accecptors – FeCl3 and PCl5 have yielded complexes of composition [Nb(OC6H4C(CH3)3-2)4]×[FeCl4] and [Nb(OC6H4C(CH3)3-2)4]×[PCl6] authenticated by physicochemical and IR data.

3

Synthesis, Characterization and Reactivity of Bis(4-tert-butylphenolato)dichlorotin(IV)

Chaudhry S. C., Bandna K., Bhatt S. S., Sharma N.

Polish Journal of Chemistry

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2009

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Vol. 83, nr 9

1537-1545

EN

The bis(4-tert-butylphenolato)dichlorotin(IV) complex of composition SnCl2(OC6H4But-4)2 (1) has been synthesized by the reaction of tin tetrachloride with bimolar amount of 4-t-butylphenol in benzene under reflux and characterized by elemental analyses, molar conductance measurements, molecular weight determination, IR, 1H, 13C NMR and FAB mass spectral techniques. Thermal behaviour of the complex has been investigated using TG-DTA technique. Lewis acid character of (1) has been explored by isolating its addition compounds with some nitrogeneous bases viz. diethylamine, triethylamine, imidazole, benzimidazole (L); 2,2'-bipyridyl, and 1,10-phenanthroline (B) of composition, SnCl2(OC6H4But-4)2×2L and SnCl2(OC6H4But-4)2×B, characterized by physicochemical and IR spectral studies.

4

Synthesis, Characterization and Antifungal Activity of Mono-Oxovanadium(V) Complexes of 4-Phenylphenol

Sharma N., Thakur M., Sagar A., Chaudhry S. C.

Polish Journal of Chemistry

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2009

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Vol. 83, nr 11

1859-1870

EN

New mono-oxovanadium(V) complexes of composition VOCl3-n(OC6H4-C6H5-4)n (where n = 1 to 3) have been synthesized in quantitative yields by the in-situ reaction of VOCl3 with trimethylsilyl derivative of 4-phenylphenol and characterized by elemental analyses, molar conductance measurements and IR, 1H NMR and mass spectral methods. The reactions of complexes with a variety of nitrogenous bases viz. imidazole and benzimidazole (L); 2,2'-bipyridyl and 1,10-phenanthroline (B) yielded adducts of composition VOCl3-n(OC6H4-C6H5-4)n×2L and VOCl3-n(OC6H4-C6H5-4)n×B, proved by analytical and IR spectral data. The molecular model calculations through optimum energy minimization for the perspective geometry of the complexes have also been computed. The ligand, 4-phenylphenol, as well as the synthesized complexes show growth inhibitory activity against pathogenic fungus Fusarium oxysporum.

5

Synthesis, Characterization and Antibacterial Activity of Triorganotin(IV) Complexes of 4-Methylphenol

Sharma N., Kumar V., Thakur M., Kumari M., Chaudhry S. C.

Polish Journal of Chemistry

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2009

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Vol. 83, nr 12

2051--2065

EN

The triorganotin(IV) com plex of com po si tion Ph3Sn(OArMe-4) has been synthesized in good yields by the reaction of Ph3SnCl with Me3SiOArMe-4/NaOArMe-4, while complexes of composition Me3Sn(OArMe-4) and n-Bu3Sn(OArMe-4) (where -OArMe-4 = -OC6H4CH3-4) have been obtained from the reaction of Me3SnCl and n-Bu3SnCl with 4-methylphenol in the presence of triethylamine in carbon tetrachloride. The complexes have been characterized by elemental analyses, molar conductance measurements, molecular weight determin tion and IR, 1H and 13C NMR and mass spectral studies. Thermal behaviour of the complexes has been studied by TG and DTA techniques. The organotin(IV) complexes have also been screened for their antibacterial properties and are found to exhibit appreciable activity. The reactions of the complexes with 2-, 3-, 4-cyanopyridines yielded 1:1 adducts as confirmed by physicochemical and IR spectral data.

6

Bivalent Tin(II)-4-methoxyphenoxide: Synthesis, Characterization, Reactivity and Antifungal Activity

Chaudhry S. C., Bandna K., Bhatt S. S., Sharma N., Sagar A.

Polish Journal of Chemistry

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2009

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Vol. 83, nr 3

391-400

EN

Bivalent tin(II)-4-methoxyphenoxide of composition Sn(OC6H4OMe-4)2 (1) has been synthesized from the reaction of SnCl2 with bimolar amounts of 4-methoxyphenol and diethylamine in tetrahydrofuran and characterized by elemental analysis, molar conductance measurement and IR spectral studies. Thermal behaviour of the complex has been studied by TGA-DTA techniques. The reactivity of (1) with HgCl2 has been investigated using potentiometric and cyclic voltammetric technique. Conductometric titration of complex (1) with sodium salt of 4-methoxyphenol suggests the formation of double phenoxide of composition Na2[Sn(OC6H4OMe-4)4]. Addition compounds of composition Sn(OC6H4OMe-4)2ź2L and Sn(OC6H4OMe-4)2źB (L = diethylamine and pyridine; B= l,10-phenanthroline and 2,2'-bipyridyl) have also been prepared and characterized by physicochemical and IR spectral studies. The complex (1) has also been screened for its antifungal activity.