Selenols and their Metal Salts

Benzeneselenol, a representative selenol, is a colorless liquid of greater acidity than benzenefhiol [pK = 5.9 (PhSeH) 6.5 (PhSH)]. Benzeneselenol is usually synfhesized by the reaction of phenylmagnesium bromide with metallic selenium then quenching wifh aqueous hydrochloric acid [10]. Similar hydrolysis of the sodium phenylseleno(triethoxy)borate complex prepared by fhe reduction of diphenyl diselenide wifh sodium borohydride is a convenient alternative [11]. 

Because of its acidity benzeneselenol gives phenylselenolate ions in fhe presence of bases such as MeLi (in EtgO) [13] and NaH (in THF) [14]. Sodium selenolate prepared by NaBH4 reduction of (PhSe)2 is believed to be a complex with triethyl borate 

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