1383572-25-5Relevant academic research and scientific papers
A new ONO3- trianionic pincer-type ligand for generating highly nucleophilic metal-carbon multiple bonds
O'Reilly, Matthew E.,Ghiviriga, Ion,Abboud, Khalil A.,Veige, Adam S.
, p. 11185 - 11195 (2012)
Appending an amine to a C=C double bond drastically increases the nucleophilicity of the β-carbon atom of the alkene to form an enamine. In this report, we present the synthesis and characterization of a novel CF 3-ONO3- trianionic pincer-type ligand, rationally designed to mimic enamines within a metal coordination sphere. Presented is a synthetic strategy to create enhanced nucleophilic tungsten-alkylidene and -alkylidyne complexes. Specifically, we present the synthesis and characterization of the new CF3-ONO3- trianionic pincer tungsten-alkylidene [CF3-ONO]W=CH(Et)(OtBu) (2) and -alkylidyne {MePPh 3}{[CF3-ONO]W≡C(Et)(OtBu)} (3) complexes. Characterization involves a combination of multinuclear NMR spectroscopy, combustion analysis, DFT computations, and single crystal X-ray analysis for complexes 2 and 3. Exhibiting unique nucleophilic reactivity, 3 reacts with MeOTf to yield [CF3-ONO]W=C(Me)(Et)(OtBu) (4), but the bulkier Me3SiOTf silylates the tert-butoxide, which subsequently undergoes isobutylene expulsion to form [CF3-ONO]W=CH(Et)(OSiMe 3) (5). A DFT calculation performed on a model complex of 3, namely, [CF3-ONO]W≡C(Et)(OtBu) (3′), reveals the amide participates in an enamine-type bonding combination. For complex 2, the Lewis acids MeOTf, Me3SiOTf, and B(C6F5)3 catalyze isobutylene expulsion to yield the tungsten-oxo complex [CF 3-ONO]W(O)(nPr) (6).
ONO PINCER LIGANDS AND ONO PINCER LIGAND COMPRISING METAL COMPLEXES
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Page/Page column 16, (2012/12/13)
Embodiments of the invention are directed to ONO pinccr ligands that can be in a trianionic, protonated or protonated equivalent form. The ONO pincer ligand can be combined with a transition metal comprising compound to form an ONO pincer ligand comprising transition metal complex. By choice of the ONO pincer ligand structure, the steric and electronic properties of the transition metal complexes therefrom can be controlled. The ONO pincer ligands comprise a central nitrogen atom that is disubstituted with a pair of three atom comprising bridges where the three atoms are three sp2 hybridized carbons or the three atoms are a pair of sp2 hybridized carbons and an sp3 hybridized carbon or silicon.
