(a) Two-electron reduction of B₅H₉ followed by protonation is a convenient route to B₅H₁₁. What structural change (and why) do you expect the B₅ cage to undergo during this reaction?

(b) Account for the fact that the solution ¹¹B NMR spectrum of [B₃H₈]‾ (13.40) exhibits one signal which is a binomial nonet.

(c) The photolysis of B₅H₉ leads to the formation of a mixture of three isomers of B₁₀H₁₆. The products arise from the intermolecular elimination of H₂. Suggest the nature of the product, and the reason that three isomers are formed.

Transcribed Image Text:

B10 H14+ 13X₂- In an autoclave 470 K, 20h B9X9 + BX3 + 14HX (X Br or I) (13.40)