Английская Википедия:Borane carbonyl
Borane carbonyl is the inorganic compound with the formula Шаблон:Chem2. This colorless gas is the adduct of borane and carbon monoxide. It is usually prepared by combining borane-ether complexes and CO. The compound is mainly of theoretical and pedagogical interest.[1]
Structure and properties
The structure of the molecule of borane carbonyl is Шаблон:Chem2. The Шаблон:Chem2 linkage is linear. The coordination geometry around the boron atom is tetrahedral. The bond distances are 114.0 pm for the Шаблон:Chem2 bond, 152.9 pm for the Шаблон:Chem2 bond, and 119.4 pm for the Шаблон:Chem2 bonds. The Шаблон:Chem2 bond angle is 113.7°. The Шаблон:Chem2 vibrational band is at 2164.7 cm−1, around 22 cm−1 higher than that of free CO.[2]
Borane carbonyl has an enthalpy of vaporization of 19.7 kJ/mol (4750 cal/mol).[3] It has electronic state 1A1 and point group symmetry C3v.[4]
Synthesis and reactions
Borane carbonyl was discovered in 1937 by reacting diborane with excess carbon monoxide, with the equation:
The reaction quickly reaches equilibrium at 100°C, but at room temperature, the reverse reaction is slow enough to isolate borane carbonyl. This reaction is performed at high pressures, typically with a maximum pressure observed of 1000 to 1600 psi (68.95 to 110.32 bar).[5] It can also be performed at atmospheric pressure, with ethers as a catalyst.[6][7]
A more recent synthesis of borane carbonyl involves slowly bubbling carbon monoxide through a 1 M Шаблон:Chem2 solution. The resulting gas stream can be condensed and subsequently bubbled through ethanolic potassium hydroxide to produce the boranocarbonate anion (Шаблон:Chem2 or Шаблон:Chem2).[7]
References
