Solvation of lons with Ether ether solvates cations: alcohol solvates cations and anions: R (not well solvated) R O-R Copyright2010 Pearson Prentice Hall,Inc. An ionic substance such as lithium iodide is moderately soluble in ethers because the small lithium cation is strongly solvated by the ether's lone pairs of electrons. Unlike alcohols,ether cannot serve as hydrogen- bond donors,so they do not solvate small anions well. Chapter 14 6
Chapter 14 6 Solvation of Ions with Ether • An ionic substance such as lithium iodide is moderately soluble in ethers because the small lithium cation is strongly solvated by the ether’s lone pairs of electrons. • Unlike alcohols, ether cannot serve as hydrogenbond donors, so they do not solvate small anions well
Ether Complexes R Grignard reagents:Complexation of O—R H an ether with a Grignard reagent stabilizes the reagent and helps H-C一Mg-X keep it in solution. H RO④ R H Electrophiles:The ethers )B-H nonbonding electrons stabilize the H borane (BH3). BH3·THF Chapter 14 7
Chapter 14 7 Ether Complexes • Grignard reagents: Complexation of an ether with a Grignard reagent stabilizes the reagent and helps keep it in solution. • Electrophiles: The ethers nonbonding electrons stabilize the borane (BH3). O B H H H + _ BH3 THF
Crown Ether Complexes 12-crown-4 15-crown-5 18-crown-6 18-crown-6 EPM of 18-crown-6 solvates Lit solvates Na solvates K with K+solvated Copyright2010 Pearson Prentice Hall,Inc. Crown ethers can complex metal cations inside the ring. The size of the cation will determine the size of the ring needed. Complexation by crown ethers often allows polar inorganic salts to dissolve in nonpolar organic solvents. Chapter 14 8
Chapter 14 8 Crown Ether Complexes • Crown ethers can complex metal cations inside the ring. • The size of the cation will determine the size of the ring needed. • Complexation by crown ethers often allows polar inorganic salts to dissolve in nonpolar organic solvents
Common Names of Ethers Name the two alkyl groups attached to the oxygen and add the word ether. Name the groups in alphabetical order Symmetrical:Use dialkyl or just alkyl. CH3 CH3CH2-O-CH2CH3 CH3-O-C-CH3 CH3 diethyl ether or t-butyl methyl ether or ethyl ether Chapter 14 methyl t-butyl ether s
Chapter 14 9 Common Names of Ethers • Name the two alkyl groups attached to the oxygen and add the word ether. • Name the groups in alphabetical order • Symmetrical: Use dialkyl or just alkyl. diethyl ether or ethyl ether t-butyl methyl ether or methyl t-butyl ether CH3CH2 O CH2CH3 CH3 O C CH3 CH3 CH3
IUPAC Names The more complex alkyl group is the alkane name.The small group (with the oxygen) becomes an "alkoxy"group. CH3 O-CH3 CH3-O-C-CH3 CH3 2-methyl-2-methoxypropane Methoxycyclohexane Chapter 14 10
Chapter 14 10 IUPAC Names • The more complex alkyl group is the alkane name. The small group (with the oxygen) becomes an “alkoxy” group. 2-methyl-2-methoxypropane Methoxycyclohexane CH3 O C CH3 CH3 CH3 O CH3