N-(o-Aminophenyl)-2-oxy-4-methoxybenzophenoneimine – Si-chelation by a tridentate ONN ligand system versus benzimidazoline formation

Lippe, Katrin; Gerlach, Daniela; Kroke, Edwin; Wagler, Jörg

doi:10.1016/j.inoche.2008.01.025

Cited by 19 publications

(2 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As reported by Atkins et al, the reaction of o -phenylenediamine and 2-hydroxybenzophenones in the presence of triethyl orthoformate and piperidine gives rise to N -( o -aminophenyl)-2-hydroxybenzophenoneimines, which can be converted into ONNO ligand systems by a second equivalent of the hydroxybenzophenone and into ONN′O′ ligand systems by reaction with 2-hydroxybenzaldehydes. These procedures allowed the syntheses of compounds 1 , 2 , and 3 (Scheme ). Single-crystal X-ray diffraction analyses of 2 and 3 (Tables and ) already reveal some differences between these symmetric and nonsymmetric ONNO and ONN′O′ chelators, respectively.…”

Section: Resultsmentioning

confidence: 99%

Hypercoordinate Organosilicon Complexes of an ONN′O′ Chelating Ligand: Regio- and Diastereoselectivity of Rearrangement Reactions in Si−Salphen Systems

et al. 2008

Self Cite

View full text Add to dashboard Cite

Reactions of various organochlorosilanes with the salphen-like tetradentate (ONN′O′) ligand o-HO-p-MeO-C6H3C(Ph)N(o-C6H4)NCHC6H4-o-OH, bearing two chemically and sterically different imine moieties, provided insights into the regio- and diastereoselectivity of various rearrangement reactions. Whereas thermally driven allyl- and UV-induced phenyl-shift reactions from the Si to an imine carbon atom yield one diastereomer, hydride-shift reactions were found to be less diastereoselective; however, only the sterically less demanding salicylaldimine site was attacked in all these rearrangement reactions.

show abstract

Section: Resultsmentioning

confidence: 99%

Hypercoordinate Organosilicon Complexes of an ONN′O′ Chelating Ligand: Regio- and Diastereoselectivity of Rearrangement Reactions in Si−Salphen Systems

et al. 2008

Self Cite

View full text Add to dashboard Cite

show abstract

“…Neutral hexacoordinate silicon dichelates based on hydrazide-derived bidentate ligands ( 1 ) show significant structural and chemical flexibility, manifest in a variety of properties. − It has been shown that such dichelates bearing a halo ligand (Y = Cl, Br, I) generally can interconvert between hexa- and pentacoordination through equilibrium ionic dissociation, driven by hydrogen-bond donor solvents capable of solvating the halide anion (eq ) . Changes in the coordination number of silicon complexes have also been reported resulting from various intramolecular rearrangements and other reactions: photochemical conversion of tetra- to pentacoordinate compounds, , as well as chemical increase of the silicon coordination number from five to six by reaction with KF; migration of a silicon ligand from silicon to an adjacent CN double bond; as well as carbon-ligand migration − and a case of intramolecular hydrosilylation by migration of a hydrido ligand from silicon to an adjacent imino carbon .…”

Section: Introductionmentioning

confidence: 99%

Reversible Neutral Dissociation of the N−Si Dative Bond in Hexacoordinate Hydrido Complexes of Silicon

et al. 2008

View full text Add to dashboard Cite

Hexacoordinate silicon dichelates with hydrido and methyl monodentate ligands were prepared by transsilylation. The temperature-dependent 29 Si NMR spectra of toluene-d 8 or CDCl 3 solutions provide evidence for a reversible, neutral dissociation of the dative N-Si bond, accompanied by a shift of the 29 Si resonance from high field (hexacoordinate) to lower field (pentacoordinate) with increasing temperature. When a phenyl group is attached directly to silicon (replacing methyl), the N-Si dissociation is prevented, presumably due to electron withdrawal by the phenyl. Two of the silicon complexes were characterized by crystallographic analysis. Quantum chemical calculations at the RB3LYP/6-31G(d) level confirm the stability of an N-Si dissociated species (1.03 kcal mol -1 lower in energy than the hexacoordinate dichelate) and rule out the alternative possibility of an O-Si zwitterionic dissociation, thus supporting the mechanism suggested by the experimental results.

show abstract

2‐Acylpyrroles as Mono‐anionic O,N‐Chelating Ligands in Silicon Coordination Chemistry

Kämpfe

Brendler

Kroke

et al. 2014

Chemistry A European J

Self Cite

View full text Add to dashboard Cite

Kryptopyrrole (2,4-dimethyl-3-ethylpyrrole) was acylated with, for example, benzoyl chloride to afford 2-benzoyl-3,5-dimethyl-4-ethylpyrrole (L(1)H). With SiCl4 this ligand reacts under liberation of HCl and formation of the complex L(1)2SiCl2. In related reactions with HSiCl3 or H2SiCl2, the same chlorosilicon complex is formed under liberation of HCl and H2 or liberation of H2, respectively. The chlorine atoms of L(1)2SiCl2 can be replaced by fluoride and triflate using ZnF2 and Me3Si-OTf, respectively. The use of a supporting base (triethylamine) is required for the complexation of phenyltrichlorosilane and diphenyldichlorosilane. The complexes L(1)2SiCl2, L(1)2SiF2, L(1)2Si(OTf)2, L(1)2SiPhCl, and L(1)2SiPh2 exhibit various configurations of the octahedral silicon coordination spheres (i.e. cis or trans configuration of the monodentate substituents, different orientations of the bidentate chelating ligands relative to each other). Furthermore, cationic silicon complexes L(1)3Si(+) and L(1) SiPh(+) were synthesized by chloride abstraction with GaCl3. In contrast, reaction of L(1)2SiCl2 with a third equivalent of L(1)H in the presence of excess triethylamine produced a charge-neutral hexacoordinate Si complex with a new tetradentate chelating ligand which formed by Si-templated C-C coupling of two ligands L(1).

show abstract

N-(o-Aminophenyl)-2-oxy-4-methoxybenzophenoneimine – Si-chelation by a tridentate ONN ligand system versus benzimidazoline formation

Cited by 19 publications

References 27 publications

Hypercoordinate Organosilicon Complexes of an ONN′O′ Chelating Ligand: Regio- and Diastereoselectivity of Rearrangement Reactions in Si−Salphen Systems

Hypercoordinate Organosilicon Complexes of an ONN′O′ Chelating Ligand: Regio- and Diastereoselectivity of Rearrangement Reactions in Si−Salphen Systems

Reversible Neutral Dissociation of the N−Si Dative Bond in Hexacoordinate Hydrido Complexes of Silicon

2‐Acylpyrroles as Mono‐anionic O,N‐Chelating Ligands in Silicon Coordination Chemistry

Contact Info

Product

Resources

About