Mechanistic studies of C-C bond cleavage of nitriles by dinuclear metal cryptates.
We previously reported that dinuclear copper(II) cryptate [Cu(2)L](4+) cleaves the C-C bond of acetonitrile at room temperature to produce a cyano-bridged dinuclear cryptate and methanol, whereby the reaction mechanism has not yet become clear. We have now systemically investigated this reaction, and four cryptates, [Cu(2)L](ClO(4))(4) (1), [Zn(2)L](ClO(4))(4) (2), [Cu(2)L(H(2)O)(2)](CF(3)SO(3))(4) (5), and [Cu(2)L(OH)(OH(2))](ClO(4))(3) (6) are reported here. Cryptates 1 and 2 can cleave the C--C bonds of acetonitrile, propionitrile, and benzonitrile at room temperature under open atmospheric conditions to give cyano-bridged cryptates [Cu(2)L(CN)](ClO(4))(3) (3) and [Zn(2)L(CN)](ClO(4))(3) (4), respectively, and the corresponding alcohol. In contrast, 5 and 6 do not show any C-C bond activation of nitriles, as the interior axial positions of Cu(II) in 5 and 6 are occupied by water/OH(-). The C-C bond cleavage of (S)-(+)-2-methylbutyronitrile by 2 produced (R)-(-)-2-butanol only; that is, the cleavage reaction proceeds through an S(N)2 pathway (Walden inversion).
Yang
Li-Zi
LZ
MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, State Key Laboratory of Optoelectronic Materials and Technologies and School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275, China.
Li
Yu
Y
Zhuang
Xiao-Mei
XM
Jiang
Long
L
Chen
Jia-Mei
JM
Luck
Rudy L
RL
Lu
Tong-Bu
TB
D003300:Copper / Q000737:chemistry*; D043844:Crown Ethers / Q000737:chemistry*; D018360:Crystallography, X-Ray; D008670:Metals / Q000737:chemistry*; D015394:Molecular Structure; D009570:Nitriles / Q000737:chemistry*; D015032:Zinc / Q000737:chemistry*
C547130:(S)-2-methylbutyronitrile; D043844:Crown Ethers; D008670:Metals; D009570:Nitriles; D003300:Copper; D015032:Zinc