- Studies on the reactivity of alkoxo-niobium(V) compounds towards O,O- or S,S-enolate ligands. Synthesis and structural characterisation of (alkoxo)(β-diketonato)- and (alkoxo)[dialkyl(aryl)dithiocarbamato] complexes of niobium(V)
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Reaction of the alkoxo-containing niobium complexes [NbCl3(OR)2]2 (R=Me, Et, iPr) with β-diketones R′COCH2COR′ [R′=Me (Hacac); R′=tBu (Hdpm); R′=Ph (Hdbm)] in a 1:2 molar ratio, afforded the corresponding (alkoxo)(β-diketonato) complexes [NbCl2(OR)2(O,O′-R′COCHCOR′)] (R=Me, R′=Me 1; R=Et, R′=Me 2; R=iPr, R′=Me 3; R=Me, R′=tBu 4; R=Et, R′=tBu 5; R=iPr, R′=tBu 6; R=Me, R′=Ph 7; R=Et, R′=Ph 8; R=iPr, R′=Ph 9). The molecular structure of 8 was elucidated by an X-ray diffraction study. The kinetics of the displacement reaction of 5 and 8 with Hacac to give complex 2 and the corresponding β-diketone Hdpm or Hdbm have also been studied by 1H-NMR spectroscopy. Finally, the complexes [NbCl3(OR)2]2 reacted with reagents of the type Na(S2CNR′2), in a 1:4 molar ratio, to give the corresponding (alkoxo)[dialkyl(aryl)dithiocarbamato] complexes [NbCl(OR)2(S,S′-S2CNR′)2] (R=Me, R′=Me 10; R=Me, R′=Et 11; R=Me, R′=Bz 12; R=Et, R′=Me 13; R=Et, R′=Et 14; R=Et, R′=Bz 15; R=iPr, R′=Me 16; R=iPr, R′=Et 17; R=iPr, R′=Bz 18). All complexes were characterised spectroscopically.
- Anti?olo,Carrillo-Hermosilla,Fernández-Baeza,García-Yuste,Otero,Palomares,Rodriguez,Sánchez-Barba
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p. 194 - 202
(2007/10/03)
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- Synthesis and characterization of N,N-dialkyldithiocarbamate complexes of niobium(V) and tantalum(V)
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N,N-Dialkyldithiocarbamate salts react with niobium and tantalum pentahalides in methanol to give compounds with the stoichiometry MX(OCH3)2(S2CNR2)2. Compounds were prepared in which X was Cl, Br, and NCS and R was CH3, C2H5, and CH2C6H5. The compounds are air-stable crystalline materials. Solutions of the compounds in CH3Cl, CCl4, and t-butyl alcohol arc stable; they decompose in primary alcohols. The compounds are nonelectrolytes and are monomeric. Ultraviolet, infrared, and proton magnetic resonance spectral data are presented.
- Pantaleo, Daniel C.,Johnson, Ronald C.
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p. 1248 - 1252
(2008/10/08)
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