Siloxides are

chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...

s with the formula R₃SiOM, where R is usually an organic group and M is usually a

metal A metal () is a material that, when polished or fractured, shows a lustrous appearance, and conducts electrical resistivity and conductivity, electricity and thermal conductivity, heat relatively well. These properties are all associated wit ...

cation An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convent ...

. Also called silanolates, they are derived by

deprotonation Deprotonation (or dehydronation) is the removal (transfer) of a proton (or hydron, or hydrogen cation), (H+) from a Brønsted–Lowry acid in an acid–base reaction.Henry Jakubowski, Biochemistry Online Chapter 2A3, https://employees.csbsju.ed ...

of silanols. They also arise by the degradation of

siloxanes In organosilicon chemistry, a siloxane is an organic compound containing a functional group of two silicon atoms bound to an oxygen atom: . The parent siloxanes include the oligomeric and polymeric hydrides with the formulae and . Siloxanes ...

by base: :R₃SiOSiR₃ + 2 NaOH → 2 R₃SiONa + H₂O Cleavage of cyclic siloxanes affords siloxides: :(Me₂SiO)₃ + MeLi → Me₃SiOSiMe₂OSiMe₂OLi These anions function as

ligand In coordination chemistry, a ligand is an ion or molecule with a functional group that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's el ...

s for metal ions, forming complexes similar to metal

alkoxide In chemistry, an alkoxide is the conjugate base of an alcohol and therefore consists of an organic group bonded to a negatively charged oxygen atom. They are written as , where R is the organyl substituent. Alkoxides are strong bases and, whe ...

Sodium trimethylsiloxide Sodium trimethylsiloxide is an organosilicon compound with the formula NaOSi(CH3)3. It is the sodium salt of the conjugate base derived from trimethylsilanol. A white solid, its molecular structure consists of a cluster with Na-O-Na linkages on t ...

is useful for generating metal complexes by

salt metathesis reaction A salt metathesis reaction (also called a double displacement reaction, double replacement reaction, or double decomposition) is a type of chemical reaction in which two ionic compounds in aqueous solution exchange their component ions to form two ...

s. A very bulky siloxide is

tert-butyl In organic chemistry, butyl is a four-carbon alkyl radical or substituent group with general chemical formula , derived from either of the two isomers (''n''-butane and isobutane) of butane. The isomer ''n''-butane can connect in two ways, giv ...

₃SiO⁻, sometimes called silox. Siloxides are weaker net donors than

alkoxides In chemistry, an alkoxide is the conjugate base of an alcohol and therefore consists of an organic group bonded to a negatively charged oxygen atom. They are written as , where R is the organyl substituent. Alkoxides are strong bases and, when ...

because p_π-d donation has to compete with backbonding from the oxygen atom into the low-lying Si-C σ^* orbitals.{{cite journal , last1=Krempner , first1=Clemens , title=Role of Siloxides in Transition Metal Chemistry and Homogeneous Catalysis , journal=Eur. J. Inorg. Chem. , year=2011 , volume=2011 , issue=11 , page=1689 , doi=10.1002/ejic.201100044 , url=https://chemistry-europe.onlinelibrary.wiley.com/doi/10.1002/ejic.201100044, url-access=subscription

References

Organosilicon compounds