Synthesis and structural characterisation of an unusual phosphine-borane-substituted organoplumbate

Treatment of (n-Pr2P)2CH2 with BH3·SMe2 yields the phosphine-borane {n-Pr2P(BH3)}2CH2 (1) as an air-stable colourless oil. Treatment of 1 with n-BuLi affords [{n-Pr2P(BH3)}2CH]Li (2). The reaction of 2 with PbI2 gives the highly insoluble phosphine-borane-substituted plumbate [{n-Pr2P(BH3)}2CHPbI2]2[Li(THF)4]2·THF (3). The solid-state structure of 3 contains an unusual dimeric organoplumbate dianion.

The reaction between PbI2 and [{n-Pr2P(BH3)}2CH]Li(THF)2 does not yield the corresponding plumbylene, but instead gives the unusual organoplumbate salt [[{n-Pr2P(BH3)}2CH]PbI2]2[Li(THF)4]2(THF)0.5 (3).Figure optionsDownload as PowerPoint slideHighlights
► Unexpected reaction between a lithium alkyl and PbI2.
► Synthesis of a unique organoplumbate salt.
► Unusual structure of organoplumbate dianion.