GATE 2019 CY – Question 41

Inorganic Chemistry · Organometallics: 18-Electron rule; metal-alkyl, metal-carbonyl, metal-olefin and metal-carbene complexes and metallocenes. Fluxionality in organometallic complexes. Types of organometallic reactions. Homogeneous catalysis – Hydrogenation, hydroformylation, methanol to acetic acid process, olefin metathesis and Wacker oxidation. Heterogeneous catalysis – Fischer-Tropsch reaction, Ziegler-Natta polymerization. · 2 marks · Multiple choice

Which hapticity representation is appropriate for W(Cp)₂(CO)₂, where Cp is cyclopentadienyl?

$[W(\eta^1\!{-}Cp)(\eta^3\!{-}Cp)(CO)_2]$
$[W(\eta^1\!{-}Cp)(\eta^5\!{-}Cp)(CO)_2]$
$[W(\eta^3\!{-}Cp)(\eta^5\!{-}Cp)(CO)_2]$
$[W(\eta^5\!{-}Cp)_2(CO)_2]$

Practise this question in The GATE Grind →

Show answer and explanation

Correct answer: (C) $[W(\eta^3\!{-}Cp)(\eta^5\!{-}Cp)(CO)_2]$

Explanation

Use neutral electron counting: W contributes 6 and two CO ligands contribute 4. An η⁵ Cp contributes 5 and an η³ Cp contributes 3, giving 6+4+5+3=18 electrons. Two η⁵ rings would give 20; ring slippage of one ring to η³ removes two donated electrons. Thus C.

More Organometallics: 18-Electron rule; metal-alkyl, metal-carbonyl, metal-olefin and metal-carbene complexes and metallocenes. Fluxionality in organometallic complexes. Types of organometallic reactions. Homogeneous catalysis – Hydrogenation, hydroformylation, methanol to acetic acid process, olefin metathesis and Wacker oxidation. Heterogeneous catalysis – Fischer-Tropsch reaction, Ziegler-Natta polymerization. questions

GATE 2024 CY Q11 – Among the following, the compound with the lowest CO stretching frequency is
GATE 2024 CY Q31 – The number of metal-metal bond(s) in the complex [(5-Cp)Mo(CO) 2] 2 is x and in [(5-Cp)…
GATE 2024 CY Q38 – The heptacity of allyl and Cp and the ligation mode of NO in the thermodynamically stable…
GATE 2024 CY Q39 – In the following reactions, the structures of I, II, and III, respectively, are
GATE 2024 CY Q59 – The turnover frequency (in h−1) of a reaction where 5 mol% of a catalyst is required for…
GATE 2025 CY Q21 – The Vaska’s complex trans-IrCl(CO)(PPh3)2 shows a band at 1967 cm-1 for the νCO stretching…

All Organometallics: 18-Electron rule; metal-alkyl, metal-carbonyl, metal-olefin and metal-carbene complexes and metallocenes. Fluxionality in organometallic complexes. Types of organometallic reactions. Homogeneous catalysis – Hydrogenation, hydroformylation, methanol to acetic acid process, olefin metathesis and Wacker oxidation. Heterogeneous catalysis – Fischer-Tropsch reaction, Ziegler-Natta polymerization. questions →