Ph2SiH2

Ph2SiH2, commonly called diphenylsilane, is an organosilicon compound with the formula C12H12Si. The silicon center is bonded to two phenyl groups and two hydrogens, giving a tetrahedral geometry characteristic of silane derivatives. It belongs to the family of hydrosilanes and functions as a hydride donor in various catalytic transformations, including reductions and hydrosilylation reactions.

Preparation of Ph2SiH2 is typically achieved by the reduction of dichlorodiphenylsilane (Ph2SiCl2) with reducing agents such as lithium aluminium hydride or sodium borohydride. Alternative routes include catalytic or chemical hydrosilylation methods starting from accessible silicon-chloride precursors and hydrogen sources.

Physical properties of Ph2SiH2 include being a colorless liquid at room temperature in many samples, with moderate volatility. It is relatively moisture- and air-sensitive, tending to hydrolyze slowly upon exposure to moisture to form silanols and hydrogen gas, so handling is usually conducted under inert atmospheres.

Reactivity and applications center on the Si–H bond, which can be activated by transition-metal catalysts or frustrated Lewis pairs to transfer hydride to unsaturated substrates such as alkenes, ketones, and imines. Oxidation or hydrolysis of Ph2SiH2 can lead to silanols or siloxane formation, enabling routes to more complex silicon-containing materials.

As a reagent in organosilicon chemistry, Ph2SiH2 is used as a hydride donor and as a versatile building block for synthesizing diaryl silanes and related compounds. Safety considerations include handling under appropriate containment and avoidance of moisture and inhalation of vapors.