Q93 · CSIR-NET Chemistry, December 2019
Paper: CSIR-NET December 2019 · Subject: Inorganic Chemistry · Chapter: Organometallic Compounds · Topic: Cluster Compounds Wade Rules · Marks: 2 · Difficulty: Medium
The main product of nucleoplallic attack of $\mathrm{H^{-}}$ on the complex ion given below is 
(a)
(b)
(c)
(d)
Answer
Answer: B ✓ checked by 4AB · confidence medium
The source book printed no answer; this one was worked out and checked — see the explanation.
Explanation
By the Davies–Green–Mingos rules, nucleophiles attack even before odd polyenes and open before closed. H⁻ therefore adds to a terminus of the open η⁴-diene, giving an η³-1-methylallyl ligand, with benzene and the allyl untouched (b).
Study loop for Organometallic Compounds