Switching between penta- and hexacoordination with salen-silicon-complexes

Wagler, Jörg; Böhme, Uwe; Brendler, Erica; Thomas, B.; Goutal, Sigrid; Mayr, Herbert; Kempf, Bernhard; Remennikov, G. Ya.; Roewer, Gerhard

doi:10.1016/j.ica.2005.03.036

Cited by 47 publications

(22 citation statements)

References 49 publications

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“…In order to corroborate the geometry of the complexes, 29 Si and 119 Sn NMR spectra were recorded and sharp signals from δ −15 to −19 and from δ −105 to −110 were assigned to (R 3 Si) 2 L and R 2 SiL complexes, respectively, which have penta‐ and hexa‐coordinated states around the silicon atom . Similarly, in case of tin complexes, sharp signals from δ – 150 to −159 and from δ −400 to −415 indicated penta‐ and hexa‐coordinated state around the tin atom for (R 3 Sn) 2 L‐ and R 2 SnL‐type of complexes, respectively (Fig.…”

Section: Resultsmentioning

confidence: 99%

Synthesis, characterization, and quantitative structure–activity relationship studies of bioactive dehydroacetic acid and amino ether Schiff base complexes

Devi

Kumar

2016

Heteroatom Chemistry

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Structural aspects of organosilicon(IV) and organotin(IV) complexes with dehydroacetic acid and amino ether Schiff base ligand have been described with the help of elemental analyses, conductance measurements, UV–Vis, infrared, multinuclear magnetic resonance, mass spectroscopy as well as thermogravimetric analysis, and X‐ray diffraction studies. Analysis of data suggested that the Schiff base provides two bidentate NO domains and was coordinated to silicon and tin moiety through the imine nitrogen and hydroxyl oxygen atom. Complexes were found to be nonelectrolytic and monomeric in nature. The thermal decomposition for tin compounds occurred in two steps and resulted into the formation of pure SnO2 as end product. The in vitro biological effects of the synthesized compounds were tested against two Gram‐positive and two Gram‐negative bacteria. The results of biological activity showed that all the complexes have enhanced activity as compared with the corresponding ligand, and compounds 5, 9, 11, 12, 13, 15, 16, and 17 were more potent than the standard drug ciprofloxacin. Compound 17 exhibited best antibacterial activity with lowest minimum inhibitory concentration value and maximum zone of inhibition. Further, quantitative structure–activity relationship studies pointed out that more stable compound were more active as antibacterial agents.

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Section: Resultsmentioning

confidence: 99%

Synthesis, characterization, and quantitative structure–activity relationship studies of bioactive dehydroacetic acid and amino ether Schiff base complexes

Devi

Kumar

2016

Heteroatom Chemistry

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“…Surprisingly, compound 17 exhibits the tetradentate (ONNO) ligand in a mer-fac coordination mode. In a previous report [21] we had demonstrated that a complex of the type (ONNO)SnPhCl with a related salen-type ligand might exhibit this unexpected coordination pattern whereas in other salen-Sncomplexes (ONNO)SnR 2 (comprising two identical substituents R) the Sn-bound monodentate groups R are trans-disposed to one another [22]. Now complex 17 clearly shows that even complexes of the general pattern (ONNO)SnR 2 may also comprise a salen-type ligand in mer-fac coordination mode.…”

Section: Page 3 Ofmentioning

confidence: 85%

Photo‐Driven Si‐C Bond Cleavage in Hexacoordinate Silicon Complexes

Wagler

Roewer

Gerlach

2009

Zeitschrift anorg allge chemie

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Abstract. Hexacoordinate diorganosilicon complexes of the type (ONNO)SiRR', with (ONNO) being a di-anionic salen-type Schiff base ligand, were shown to undergo Si−C bond cleavage and intramolecular rearrangement (1,3-shift of R' to a former imine carbon atom) upon irradiation with UV. The course of this reaction depends on the nature of Sibound substituents: Whereas complexes (ONNO)SiMe2 and (ONNO)SiPh2 give rise to the rearrangement of a methyl and a phenyl group, respectively, complexes of the type (ONNO)Si(aryl)(alkyl) were found to undergo Si−C(alkyl) bond cleavage exclusively. Furthermore, such alkyl groups bearing β-H atoms may lead to β-H transfer to the imine carbon atom accompanied by olefin elimination. Irradiation of compounds (ONNO)SiRX, with X being a non-carbon sacrificial ligand, was shown to give rise to further side reactions: In case of X=F the unexpected formation of (ONNO)SiF2 was observed. In analogy to the photo-induced rearrangement of (ONNO)SiPh2 the heavier congenor (ONNO)GePh2 exhibits similar reactivity, whereas the related tin compound (ONNO)SnPh2 proved inert under these reaction conditions applied.

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“…Whereas SiCl 4 , PhSiCl 3 , and Ph 2 SiCl 2 were commercially available, (Anis) 2 SiCl 2 and (4-Me 2 N-C 6 H 4 )PhSiCl 2 were prepared from SiCl 4 and PhSiCl 3 , respectively, and suitable Grignard reagents (see Experimental Section). [7][8][9][10][11]18,19,[73][74][75][76][77] chelators, we have now explored silicon coordination chemistry with a dianionic tetradentate (N,N′,N′,N) chelator. Thus far, macrocyclic π-conjugated (porphyrine-and phthalocyanine-type) ligands [78][79][80][81] have been explored in silicon coordination chemistry (e.g., D [81]), and our study aims at building a bridge between these cyclic (N, …”

Section: Synthesesmentioning

confidence: 99%