Paper: CSIR-NET June 2015 · Subject: Inorganic Chemistry · Chapter: Organometallic Compounds · Topic: Organometallic Compounds – General · Marks: 2 · Difficulty: Medium
The following statements are given regarding the agostic interaction C-H----Ir observed in $\left[\operatorname{Ir}\left(\mathrm{Ph}_{3} \mathrm{P}\right)_{3} \mathrm{Cl}\right]$.
\[ \begin{array}{l} \text{(A) Upfield shift of C-H proton in }{}^{1}\mathrm{H}\text{ NMR spectrum} \\ \text{(B) Increased acid character of C-H} \\ \text{(C) } \bar{v}_{\mathrm{CO}}\text{ in IR spectrum shifts to higher wavenumber} \end{array} \]
The correct answer is/are:
(a)A and C
(b)B and C
(c)A and B
(d)C only
Answer
Answer: C ✓ checked by 4AB · confidence medium
Explanation
An agostic C–H···M interaction moves the proton upfield in ¹H NMR and weakens/acidifies the C–H bond; [Ir(PPh₃)₃Cl] has no CO, so statement C does not apply. A and B.