Beryllium Phosphine Complexes: Synthesis, Properties, and Reactivity of (PMe₃)₂BeCl₂ and (Ph₂PC₃H₆PPh₂)BeCl₂

Abstract

The directed synthesis, spectroscopic properties, and reactivity of bis(trimethylphosphine) beryllium dichloride (1) and bis(diphenylphosphino)propane beryllium dichloride (2) are reported, including the crystal structure of (PMe ) BeCl (1). These four-coordinate beryllium compounds can be alkylated with n-butyllithium ( BuLi) to give three-coordinate (Ph PC H PPh )Be Bu (3) and (PMe )Be Bu (4). PMe can be removed from (PMe )Be Bu (4) in vacuo to yield [ Bu Be] (5). For the first time, the presence of [ Bu Be] as a dimer in solution, which has been postulated for decades, could be observed spectroscopically. This novel, ether-free pathway provides access to beryllium dialkyl compounds that have never been in contact with oxygen-atom-containing reagents or solvents. This "freeness from oxygen" is crucial for semiconductor applications where oxygen is often unwanted and must be avoided at all costs.

Carboxylic Acid Ester Adducts of Beryllium Chloride and Their Role in the Synthesis of Beryllium Nitrates

“…Since the coordination shift is strongest for the carbonyl carbon nucleus, followed by the methyl group of the acetate and the formate proton in the acetates and formates, respectively, it is evident that the coordination occurs also in solution exclusively via the carbonyl oxygen atom. [14] The signals of the formate complexes are observed approximately 1 ppm downfield from the acetate compounds and show that the electron density at the beryllium atom is significantly lower in the prior compounds as would be expected. This is caused through the depleted electron density at the oxygen and therefore the adjacent carbon nucleus.…”

“…The compound crystallizes in the monoclinic space group type P2 1 /c with eight formula units in the unit cell. [14] Table 3. There are two independent molecular units in the unit cell, of which one is shown in Figure 3.…”

“…To clarify this, we decided to react anhydrous BeCl 2 with methyl, ethyl, and isopropyl acetate and formate. [14] In the 1 H and 13 C NMR spectra, only one set of signals for the respective ester could be observed. Anhydrous BeCl 2 dissolves readily upon addition of the carboxylic acid esters.…”

Beryllium‐Induced Conversion of Aldehydes

“…1 Ha nd 13 CNMR spectroscopice xperimentsr evealed that the pivaldehyde moiety was stable for several weeks, whereas the different chemical shifts of the signals, in comparison to the free ligand,i ndicated ac oordination towards BeCl 2 (see also Ta ble 1). [18,19,25] The molecular structure of 2a is illustratedi nF igure 1. [24] By removing the solvent, crystals of dichlorobis(2,2-dimethylpropanal)beryllium(II)( 2a)c ould be obtained as colorless blocks.…”

Berylliumkomplexe mit biologisch relevanten funktionellen Gruppen: Koordinationsgeometrien und Bindungsaffinitäten

“…Innerhalb von zwei Wochen bei Raumtemperatur kristallisierte Addukt 3.Die Produkte 2 und 4 wurden hingegen bei 80 8 8Cumkristallisiert. [24] Dies ist ein Hinweis auf die stärkere Bindungsaffinitätd er Hydroxygruppe hin zum Beryllium als im Fall von Estern, Ethern oder Aldehyden, während die Be-O-Atomabstände andeuten, dass Alkohole und Carboxylate in ihrer Be-O-Bindungsstärke vergleichbar sind. Nach unserem bisherigen Kenntnisstand handelt es sich hierbei um die ersten strukturell charakterisierten Berylliumkomplexe eines Aldehyds sowie eines nicht deprotonierten Alkohols.Die Koordination des Liganden an BeCl 2 erfolgt in 2 ausschließlich über das 2) ).…”