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RESEARCH PRODUCT

Synthetic Endeavors toward Titanium Based Frustrated Lewis Pairs with Controlled Electronic and Steric Properties

Constantin G. DaniliucGerald KehrCédric BalanPierre Le GendreAdrien T. NormandAdrien T. NormandGerhard ErkerPhilippe Richard

subject

Steric effectsTetraphenylboratePhosphideStereochemistryOrganic ChemistryCationic polymerizationFrustrated Lewis pairInorganic ChemistryBenzaldehydechemistry.chemical_compoundchemistryPolymer chemistryPhosphoniumPhysical and Theoretical ChemistryPhosphine

description

A new family of cationic Ti complexes 4′ with a pendant phosphine of general formula [CpCpPTiOAr][BPh4] (Cp = η5-C5H5; CpP = η5-C5H4(CMe2)PR2) has been prepared in four steps from 6,6-dimethylfulvene. These complexes were designed to behave as Ti based frustrated Lewis pairs (FLPs). The key synthetic step is a reduction–oxidation sequence from [CpCpPTiClOAr] complexes 3 using lithium phosphide salts as the reductants and ferricinium tetraphenylborate as the oxidant. Four complexes have been structurally characterized by X-ray diffraction and show elongated Ti–P bonds, above 2.60 A. One complex (4b′: OAr = 2,6-Me2C6H3; PR2 = PCy2) reacted with benzaldehyde to form a typical FLP activation product. Complex 4b′ also reacted with 2 equiv of trans-chalcone to form a 10-membered Ti phosphonium macrocycle (6b′) by extrusion of 6,6-dimethylfulvene.

https://doi.org/10.1021/acs.organomet.5b00250