A new ONO3− trianionic pincer ligand with intermediate flexibility and its tungsten alkylidene and alkylidyne complexes. Issue 42 (7th October 2015)

• Record Type: Journal Article
• Authors: VenkatRamani, Sudarsan; Ghiviriga, Ion; Abboud, Khalil A.; Veige, Adam S.
• Is Part Of: Dalton transactions. Volume 44:Issue 42(2015)
• Page Start: 18475
• Page End: 18486
• Publication Date: 2015-10-07
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/c5dt02911b
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : This report details the synthesis and characterization of the semi-flexible [ON CH2 O]H3 (1 ) ligand and its W(vi )-alkylidene and alkylidyne complexes. Abstract : This report details the synthesis and characterization of the semi-flexible [ON CH2 O]H3 (1 ) ligand and its W(vi )-alkylidene and alkylidyne complexes. The alkylidyne complex [ON H CH2 O]WC t Bu(O t Bu) (2 ) forms as a result of alcoholysis of1 with ( t BuO)3 WC t Bu. Complex2 evolves to [ON CH2 O]WC H t Bu(O t Bu) (3 ) through proton migration from the N atom of the pincer ligand to the WC α bond. Deprotonation of2 or3 with Ph3 PCH2 affords the anionic alkylidyne {CH3 PPh3 }{[ON CH2 O]WC t Bu(O t Bu)} (4 ). Complex4 exhibits pincer-ligand-centered reactivity with electrophiles (H +, Me +, and TMS + ), in spite of its enhanced inorganic enamine interaction. Addition of 2 equiv. of HCl to4 yields the W(vi )-neopentyl complex [ON CH2 O]W(CH2 t Bu)(O t Bu)(Cl) (5 ). MeOTf or TMSOTf addition to4 generates the dianionic pincer ligated alkylidynes [ON R CH2 O]WC t Bu(O t Bu) (R = Me (6-Me ); TMS (6-TMS )). Complexes2–5 were characterized by multinuclear NMR spectroscopy, and combustion analysis. Complexes4 and5 were also characterized by single crystal X-ray diffraction. This work bridges the gap in the series involving W(vi )-alkylidynes ligated to the rigid [CF3 -ONO] 3−, and the flexible [O CH2 N CH2 O] 3− ligands. DFT computations permit comparison of the inorganic enamine effect within alkylidynes supported by all three trianionic-pincer type ONO ligands.