Complexes HM(CO)₅ and [((η⁵-C₅H₅)M'(CO)₃]₂ obey the 18-electron rule. Identify M and M' and their ¹H NMR… · ABC26IN0247
Subject: Inorganic Chemistry · Chapter: Organometallic Compounds · Topic: 18 Electron Rule · Exam: CSIR NET 2014 · Marks: 2 · Difficulty: Hard
Complexes $\mathrm{HM(CO)_5}$ and $\mathrm{[((\eta^5\text{-}C_5H_5)M'(CO)_3]_2}$ obey the 18-electron rule. Identify M and M' and their ${}^{1}\mathrm{H}$ NMR chemical shifts relative to TMS.
(a)M = Mn, $-7.5$; M' = Cr, 4.10
(b)M = Cr, $-4.10$; M' = Mn, $-7.5$
(c)M = V, $-7.5$; M' = Cr, 4.10
(d)M = Mn, $-10.22$; M' = Fe, 2.80
Answer
Answer (as printed): A
Explanation
Complex (A) HM(CO) 5 =1 + 7+ 10 =18 electron M=Mn [7 electron] 1 + 7+ 10 =18 electron Complex (B) [(η5-C5H5)M'(CO) 3] 2 [(η5-C5H5)Cr(CO) 3] 2 M'=Cr=6 electron 10+12+12+2 (M-M) bond = 36 electron. [CSIR JUNE 2015]
Explanation as extracted from the printed page; notation may be imperfect.