Crystal Structure of a BePh2 Complex that produce dimers

Organoberyllium chemistry involves the synthesis and properties of

organometallic compound Organometallic chemistry is the study of organometallic compounds, chemical compounds containing at least one chemical bond between a carbon atom of an organic molecule and a metal, including alkali, alkaline earth, and transition metals, and ...

s featuring the group 2

alkaline earth The alkaline earth metals are six chemical elements in group 2 of the periodic table. They are beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra).. The elements have very similar properties: they are al ...

metal

beryllium Beryllium is a chemical element; it has Symbol (chemistry), symbol Be and atomic number 4. It is a steel-gray, hard, strong, lightweight and brittle alkaline earth metal. It is a divalent element that occurs naturally only in combination with ...

(Be). The area remains less developed relative to the chemistry of other

main-group element In chemistry and atomic physics, the main group is the group (periodic table), group of chemical element, elements (sometimes called the representative elements) whose lightest members are represented by helium, lithium, beryllium, boron, carbon ...

s, because Be compounds are toxic and few applications have been found.

Structure

Homoleptic compounds

The coordination number of Be in organoberyllium compounds ranges from two to four. Dimethylberyllium and

dimethylmagnesium Dimethylmagnesium is an organomagnesium compound with the chemical formula . It is a white pyrophoric solid. Dimethylmagnesium is used in the synthesis of organometallic compounds. Preparation Like other dialkylmagnesium compounds, dimethylmagne ...

adopts the same structure. Diethylberyllium, however, does not structurally resemble diethylmagnesium (which has the same structure as dimethylmagnesium). This contrast is attributed to the small size of Be relative to its heavier congener Mg: Be is one of the smallest atoms on the

periodic table The periodic table, also known as the periodic table of the elements, is an ordered arrangement of the chemical elements into rows (" periods") and columns (" groups"). It is an icon of chemistry and is widely used in physics and other s ...

. Dineopentylberyllium and many other dialkyl derivatives has been reported. The

phenyl In organic chemistry, the phenyl group, or phenyl ring, is a cyclic group of atoms with the formula , and is often represented by the symbol Ph (archaically φ) or Ø. The phenyl group is closely related to benzene and can be viewed as a benzene ...

derivative is represented by trimeric Be₃Ph₆. A

terphenyl Terphenyls are a group of closely related aromatic hydrocarbons. Also known as diphenylbenzenes or triphenyls, they consist of a central benzene ring substituted with two phenyl groups. There are three substitution patterns: ''ortho''-terpheny ...

derivative is known. With bulky aryl ligands three-coordination is observed, see . Organoberyllium compounds are typically prepared by

transmetallation Transmetalation (alt. spelling: transmetallation) is a type of organometallic reaction that involves the transfer of ligands from one metal to another. It has the general form: :M1–R + M2–R′ → M1–R′ + M2–R where R and R′ can be, but ...

or alkylation of

beryllium chloride Beryllium chloride is an inorganic compound with the formula BeCl2. It is a colourless, hygroscopic solid that dissolves well in many polar solvents. Its properties are similar to those of aluminium chloride, due to beryllium's diagonal relations ...

Beryllocene

Beryllocene Beryllocene is an organoberyllium compound with the chemical formula Be(C5H5)2, first prepared in 1959. The colorless substance can be crystallized from petroleum ether in the form of white needles at −60 °C and decomposes quickly upon co ...

features both pi- and sigma-bonded cyclopentadienyl ligands. It is prepared from and potassium

cyclopentadienide Sodium cyclopentadienide is an organosodium compound with the formula C5H5Na. The compound is often abbreviated as NaCp, where Cp− is the cyclopentadienide anion. Sodium cyclopentadienide is a colorless solid, although samples often are pin ...

: :

Mixed ligand compounds

Many mixed ligand complexes are simply formed by addition of Lewis bases to diaryl and dialkylberyllium compounds. Many derivatives are known of the type are known where L = thioether, pyridine, NHC, and 1,4- Diazabutadienes. Beryllium forms a variety of complexes with ''N''-hetereocyclic carbenes (NHCs).

Low oxidation beryllium chemistry

While the +2-oxidation state is by far the most common for Be, compounds containing Be(I) and Be(0) have been described. A number of beryllium complexes with cyclic alkyl amino carbene (CAAC) ligands have been proposed to feature low-oxidation state beryllium centres. However, these low-oxidation state formulations have been contested due to the redox non-innocence of CAAC ligands. Unambiguous low-oxidation state organo-beryllium complexes with Be–Be bonds have been synthesized by the group of Simon Aldridge.

History

Dimethylberyllium was reported in 1876. A. Atterberg produced this first organoberyllium compound by treatment of

dimethylmercury Dimethylmercury is an extremely toxic organomercury compound with the formula ( CH3)2 Hg. A volatile, flammable, dense and colorless liquid, dimethylmercury is one of the strongest known neurotoxins. Less than 0.1 mL is capable of inducing ...

with elemental beryllium. The alkylation of beryllium halides was studied by H. Gilman. Early systematic work was conducted by G. E. Coates.

References

{{ChemicalBondsToCarbon Beryllium compounds Organometallic chemistry