G-7 GLOSSARY Connectivity (Section 1.7): Order in which a molecules atoms are connected. Synonymous with constitution Constitution (Section 1.7): Order of atomic connections that defines a molecule Constitutional isomers(Section 1.8): Isomers that differ in re- the n which the atoms are connected Butane (CH3 CH2CH2CH3)and isobutane [(CH3)3CH] are constitu tional isomers Cyclohexadienyl cation ( Section 12. 2): The key intermediate Copolymer (Section 10. 11): Polymer formed from two or more in electrophilic aromatic substitution reactions. It is repr ferent monome sented by the general structure Coupling constant J (Section 13.7) of the extent to hich two nuclear spins are couple simplest cases, it is equal to the distance betweer t peaks in a split NMR signal. Covalent bond (Section 1.3): Chemical bond between tw atoms that results from their sharing of two electrons petroleo m refining in which high-molecular-weight hydrocarbons are converted where e is derived from the electrophile that attacks the to lower molecular-weight ones by thermal or catalytic ca bon-earbon bond cleavage Critical micelle concentration ( Section 19.5): Concentration bove which substances such as salts of fatty acids aggre- Deactivating substituent (Sections 12.11 and 12.13): A gate to form micelles in aqueous solution. that when present in place of a hydrogen substituent Crown ether(Section 16. 4): A cyclic polyether that, via a particular reaction to occur more slowly. The term most ion-dipole attractive forces, forms stable complexes with often applied to the effect of substituents on the rate metal ions. Such complexes, along with their accompany- Debye unit(D)(Section 1.5): Unit customarily used for mea- ing anion, are soluble in nonpolar solvents C terminus (Section 27.7): The amino acid at the end of a pep- suring dipole moments tide or protein chain that has its carboxyl group intact that 1D=1×10-18 esu.cm is, in which the carboxyl group is not part of a peptide bond. Cumulated diene (Section 10.5): Diene of the type C=C=C, carboxylation(Section 19.17): Reaction of the type in which a single carbon atom participates in double bonds RCO,H - RH CO,, in which carbon dioxide is lost two others from a carboxylic acid. Decarboxylation normally occurs yanohydrin (Section 17.7): Compound of the type readily only when the carboxylic acid is a 1, 3-dicarboxylic Decoupling (Section 13. 17): In NMR spectroscopy, any RCR' process that destroys the coupling of nuclear spins between two nuclei. Two types of decoupling are employed inC NMR spectroscopy. Broadband decoupling removes all the Cyanohydrins are formed by nucleophilic addition of HCN H-C couplings; off-resonance decoupling removes all of H-C couplings except those between directly bonded atoms cycloaddition (Section 10. 12): Addition, such as the Dehydration(Section 5.9): Removal of H and OH from adja Diels-Alder reaction, in which a ring is formed ia a cyclic transition state rm is most commonly employed in ycloalkane(Section 2. 12): An alkane in which a ring of car preparation of alkenes by heating alcohols in the presence of an acid catal bon atoms is present. Cycloalkene(Section 5. 1 ) A cyclic hydrocarbon characterized Dehydrogenation(Section 5.1): Removal of the elements of H2 from adjacent atoms. The term is most commonly en by a double bond between two of the ring carbons. Cycloalkyne (Section 9.4): A cyclic hydrocarbon characterized countered in the industrial preparation of ethylene from by a triple bond between two of the ring carbons. ethane, propene from propane, 1, 3-butadiene from butane, and styrene from ethy benzene. Cyclohexadienyl anion(Section 23. 6): The key intermediate in nucleophilic aromatic substitution by the addition-elimina- Dehydrohalogenation(Section 5. 14): Reaction in which an alkyl halide, on being treated with a base such as sodium tion mechanism. It is represented by the general structure shown, where Y is the nucleophile and X is the leaving ethoxide, is converted to an alkene by loss of a proton fro one carbon and the halogen from the adjacent carbon. Delocalization (Section 1.9): Association of an electron with more than one atom. The simplest example is the shared Forward Main Menu TOC Study Guide Toc Student OLCMHHE WebsiteG-7 GLOSSARY Connectivity (Section 1.7): Order in which a molecule’s atoms are connected. Synonymous with constitution. Constitution (Section 1.7): Order of atomic connections that defines a molecule. Constitutional isomers (Section 1.8): Isomers that differ in re￾spect to the order in which the atoms are connected. Butane (CH3CH2CH2CH3) and isobutane [(CH3)3CH] are constitu￾tional isomers. Copolymer (Section 10.11): Polymer formed from two or more different monomers. Coupling constant J (Section 13.7): A measure of the extent to which two nuclear spins are coupled. In the simplest cases, it is equal to the distance between adjacent peaks in a split NMR signal. Covalent bond (Section 1.3): Chemical bond between two atoms that results from their sharing of two electrons. Cracking (Section 2.13): A key step in petroleum refining in which high-molecular-weight hydrocarbons are converted to lower molecular-weight ones by thermal or catalytic car￾bon—carbon bond cleavage. Critical micelle concentration (Section 19.5): Concentration above which substances such as salts of fatty acids aggre￾gate to form micelles in aqueous solution. Crown ether (Section 16.4): A cyclic polyether that, via ion—dipole attractive forces, forms stable complexes with metal ions. Such complexes, along with their accompany￾ing anion, are soluble in nonpolar solvents. C terminus (Section 27.7): The amino acid at the end of a pep￾tide or protein chain that has its carboxyl group intact that is, in which the carboxyl group is not part of a peptide bond. Cumulated diene (Section 10.5): Diene of the type CœCœC, in which a single carbon atom participates in double bonds with two others. Cyanohydrin (Section 17.7): Compound of the type Cyanohydrins are formed by nucleophilic addition of HCN to the carbonyl group of an aldehyde or a ketone. Cycloaddition (Section 10.12): Addition, such as the Diels—Alder reaction, in which a ring is formed via a cyclic transition state. Cycloalkane (Section 2.12): An alkane in which a ring of car￾bon atoms is present. Cycloalkene (Section 5.1): A cyclic hydrocarbon characterized by a double bond between two of the ring carbons. Cycloalkyne (Section 9.4): A cyclic hydrocarbon characterized by a triple bond between two of the ring carbons. Cyclohexadienyl anion (Section 23.6): The key intermediate in nucleophilic aromatic substitution by the addition—elimina￾tion mechanism. It is represented by the general structure shown, where Y is the nucleophile and X is the leaving group. RCR W W OH CPN Cyclohexadienyl cation (Section 12.2): The key intermediate in electrophilic aromatic substitution reactions. It is repre￾sented by the general structure where E is derived from the electrophile that attacks the ring. Deactivating substituent (Sections 12.11 and 12.13): A group that when present in place of a hydrogen substituent causes a particular reaction to occur more slowly. The term is most often applied to the effect of substituents on the rate of elec￾trophilic aromatic substitution. Debye unit (D) (Section 1.5): Unit customarily used for mea￾suring dipole moments: 1 D 1  1018 esucm Decarboxylation (Section 19.17): Reaction of the type RCO2H ±£ RH CO2, in which carbon dioxide is lost from a carboxylic acid. Decarboxylation normally occurs readily only when the carboxylic acid is a 1,3-dicarboxylic acid or a -keto acid. Decoupling (Section 13.17): In NMR spectroscopy, any process that destroys the coupling of nuclear spins between two nuclei. Two types of decoupling are employed in 13C NMR spectroscopy. Broadband decoupling removes all the 1 H—13C couplings; off-resonance decoupling removes all of 1 H—13C couplings except those between directly bonded atoms. Dehydration (Section 5.9): Removal of H and OH from adja￾cent atoms. The term is most commonly employed in the preparation of alkenes by heating alcohols in the presence of an acid catalyst. Dehydrogenation (Section 5.1): Removal of the elements of H2 from adjacent atoms. The term is most commonly en￾countered in the industrial preparation of ethylene from ethane, propene from propane, 1,3-butadiene from butane, and styrene from ethylbenzene. Dehydrohalogenation (Section 5.14): Reaction in which an alkyl halide, on being treated with a base such as sodium ethoxide, is converted to an alkene by loss of a proton from one carbon and the halogen from the adjacent carbon. Delocalization (Section 1.9): Association of an electron with more than one atom. The simplest example is the shared E H H H H H H Y X  H H H H H