N-Heterocyclic carbene, carbodiphosphorane and diphosphine adducts of beryllium dihalides: synthesis, characterisation and reduction studies

Abstract

Reaction of several N-heterocyclic carbenes, a carbodiphosphorane, and bis(diphenylphosphino)ethane (DPPE) with [BeX2(OEt2)2] (X = Br or I) have yielded a variety of beryllium dihalide adduct complexes, all of which were...

Behavior of Lewis Bases toward Diphenylberyllium

“…There are a number of beryllium-phosphine complexes published with varying coordination numbers and electronic profiles. ,, In the tetracoordinate compound [(PMe 3 ) 2 BeCl 2 ], a single resonance is observed in the 9 Be NMR spectrum at 4.1 ppm, in the 31 P NMR spectrum at −44.5 ppm, and with a Be–P splitting of 40.5 Hz. Although the spectra were recorded in CD 2 Cl 2 instead of C 6 D 6 , the chemical shift in the 9 Be NMR and 31 P NMR spectra of [(PMe 3 ) 2 BePh 2 ] are almost identical, at 4.5 and −44.2 ppm, respectively.…”

“…While beryllium complexes of neutral monodentate ligands are often reasonably soluble, coordination of neutral chelating ligands to beryllium halides often results in the formation of extremely insoluble compounds. ,− Reasons for this range from the formation of coordination polymers, , the generation of complexes with very high dipole moments , or the displacement of halides with formation of charged complexes. , The high Be–C bond strength together with the smaller polarization of this bond should, in theory, lead to more soluble complexes of “BePh 2 ” with chelating ligands, if no coordination polymers are formed. To investigate this simple bidentate ligands were employed, namely, dimethoxyethane (DME), tetramethylethylenediamine (TMEDA), and 1,2-bis­(dimethylphosphino)­ethane (DMPE).…”

“…To investigate this simple bidentate ligands were employed, namely, dimethoxyethane (DME), tetramethylethylenediamine (TMEDA), and 1,2-bis­(dimethylphosphino)­ethane (DMPE). There are numerous examples of neutral bidentate ligands with beryllium halides in the literature, ,,,, but only a small handful with diphenylberyllium . However, the latter are poorly characterized.…”

Accessing the main-group metal formyl scaffold through CO-activation in beryllium hydride complexes

“…Despite interest in the solid-state behaviour of BeH 2 over the past decades, even the structure of this binary hydride has long been a point of contention and was only elucidated relatively recently 18 , 19 . It is perhaps then unsurprising that very little molecular chemistry of beryllium hydrides has been forthcoming, with well-defined examples of such complexes limited to one example of a tris(pyrazolyl)borate beryllium hydride complex, and three examples of NHC-stabilised methyl beryllium hydride complexes 20 – 23 . The insertion chemistry of the Be–H bond, which is now well established for Mg–Ba, is non-existent outside of isolated examples of heterocyclic ring-opening processes for Be 21 , 22 , which have been subject to computational mechanistic investigations 24 .…”

Reactivity of Diphenylberyllium as a Brønsted Base and Its Synthetic Application

“…The reaction between [Be 3 Ph 6 ] and 1,3-bis-(2,6diisopropylphenyl)imidazolinium chloride (IDipp • HCl) also proceeds with protonation of a single phenyl group to produce benzene and [(IDipp)BePhCl)] (4). Whilst the structures of NHCberyllium halides and borohydrides are well studied, [39,40] there is not yet an example of an NHC-berylliumaryl halide, also viewed as a Grignard analogue. 4 is well soluble in DCM and benzene, and crystallises after storage in the latter at room temperature.…”