Aromatic compounds and its structureWhich includes aromatic compounds is• benzene compounds• The chemical compound with chemical properties such as benzene1. BenzeneBenzene
and benzene derivative compounds first synthesized by Michael Faraday
in 1825, from which the gas is used as fuel for lamps penerang.Sepuluh
years later it was discovered that benzene has the molecular formula
C6H6 thus concluded that benzene has a double bond more than alkenes.Of the oily residue is buried in the gas mains in London. Currently,
the main source of benzene, substituted benzene and aromatic compounds
are petroleum: formerly of nearly 90% coal tar compounds active
ingredients are aromatic compounds: benzene core has the formula.a. Structure of BenzeneThe double bond in benzene is different from the alkene double bond. The
double bond in alkenes can undergo addition reactions, whereas the
double bond in benzene can not you get an addition, but benzene can
react substitution. Example:Addition reaction: C2H4 + Cl2 -> C2H4Cl2Substitution reaction: C6H6 + Cl2 -> C6H5Cl + HClAccording
to Friedrich August Kekulé, six carbon atoms arranged in a cyclic
benzene irregular hexagonal shape with a bond angle of 120 °
respectively. Antaratom carbon bond is a double bond and a single alternating (conjugated).
X-ray analysis of the structure of benzene indicates that the carbon bond lengths in benzene antaratom same, ie 0.139 nm. The length of a double bond C = C is 0.134 nm and the length of C-C single bond is 0.154 nm. Thus, the carbon-carbon bonds in the benzene molecule is between double bond and a single bond. This renders the structure of Kekulé.Kekulé describe the structure of benzene by carbon atoms linked to one another to form a ring.• August Kekulé in 1865: The structure illustrates that the structure of benzene composed three double bonds in the ring 6 members.• The three double bonds can be shifted and return quickly so that the two forms may not be separated.
Orbital benzeneEach carbon atom in benzene tying 3 others using sp2 hybridized orbital forming a planar molecule.Benzene is a symmetrical molecule, hexagonal shape with a bond angle 120oEach C atom has four orbital into the p orbitals. P orbitals overlap will experience suh (overlapping) to form a cloud of electrons as the source of electrons.C. AROMATIC COMPOUNDS heterocyclicAccording to Erich Hückel, a compound that contains five or six-membered ring is aromatic if:• all the constituent atoms lie in a flat (planar)• every atom that form a ring having a 2p orbital• have the pi electrons in the cyclic arrangement of the 2p orbitals as 4n +2 (n = 0, 1, 2, 3, ...)In addition to benzene and its derivatives, there are several other types of compounds exhibit aromatic properties, which have high unsaturation and showed no reactions like alkenes. Benzene homosiklik included in the class of compounds, ie compounds that have only one type of atom in the ring system. There are heterocyclic compounds, are compounds that have more than one type of atom in the ring system, the ring is composed of one or more atoms that are not carbon atoms. For example, pyridine and pirimidina are aromatic compounds such as benzene. In pyridine one CH unit of benzene is replaced by a nitrogen atom sp2 hybridise, and in pirimidina two CH units replaced by nitrogen atoms are sp2 hybridise.Membered heterocyclic compounds of five such as furan, thiophene, pyrrole, and imidazole also includes aromatic compounds.D. TERMS OF AROMATIC COMPOUNDSAromatics Requirements:1. Molecules have cyclic and flat.2. have p orbitals perpendicular to the ring plane (pi electron delocalization allow).3. have p orbitals perpendicular to the ring plane (pi electron delocalization allow)8 siklooktatetraena not aromatic pi electrons.(Fessenden and Fessenden .463-464: 1982).A. Hückel rule
In the year 1931 a German chemist Erich Hückel, suggested that an aromatic compound to be flat, monocyclic (one ring) needs to have as many pi elketron 4N + 2, where n is an integer sebuahn. According to the Hückel rule, a ring with pi electrons as 2,6,10 or 14 can be aromatic, but the ring with 8 or 12 pi electrons, can not be. Siklooktatetraena (with 8 electrons pi) does not comply with Hückel rule for aromaticity.Why the 6 or 10 pi electrons are aromatic, whereas 8 pi electrons are not?In order to be aromatic, all pi electrons must be paired, so it is possible overlapping (overlapping) optimal resulting in delocalization perfect.
If siklooktatetraena flat and has a system similar to pi pi system of benzene, the orbital π1, π2, and π3 will be filled with six pi electrons pi.Dua remaining electrons will each occupy degenerate orbitals and π5 π4 (Hund's rule). Then not all the pi electrons will pair up and will not overlap maksimal.Jadi sikooktatetraena will not be aromatic. (Fessenden and Fessenden .464-464: 1982).Aromatic compounds must meet the following criteria:- Cyclical- Contains a delocalized p electron clouds below and above the plane of the molecule- Double bonds alternate with single bonds- Have a total number of 4N +2 p electrons, where n must bulisal numbers: if the number of electrons in a ring of a cyclic p = 12, then n = 2.5 then instead of aromatic compounds
B. Ion cyclopentadiene
Cyclopentadiene is a conjugated diene and aromatic aromatik.Alasan main reason why not is that one carbon atom is sp3, not sp2.Karbon sp3 has no p orbitals take tuk un pi bond, but when taken one of the hydrogen ions in the cyclopentadiene carbon hidrodisasi will change to sp2 and p orbitals will have that contains a pair of electrons.
Aromatic Aromatic Cation AnionAll the carbon atoms of the cyclopentadiene cation will also be sp2.Is one or both of these ions are aromatic? Each ion has five π molecular orbitals (p orbitals formed from five, one per carbon). Anion cyclopentadiene with six pi electrons (4N +), filling three orbitals and all these pi electrons that are aromatik.Tetapi berpasangan.Maka cation anion it only has four electrons (4N) to fill three orbital.Maka pi electrons is not going all berpasangan.Jadi cation is not aromatic.(Fessenden and Fessenden .465-466: 1982).
X-ray analysis of the structure of benzene indicates that the carbon bond lengths in benzene antaratom same, ie 0.139 nm. The length of a double bond C = C is 0.134 nm and the length of C-C single bond is 0.154 nm. Thus, the carbon-carbon bonds in the benzene molecule is between double bond and a single bond. This renders the structure of Kekulé.Kekulé describe the structure of benzene by carbon atoms linked to one another to form a ring.• August Kekulé in 1865: The structure illustrates that the structure of benzene composed three double bonds in the ring 6 members.• The three double bonds can be shifted and return quickly so that the two forms may not be separated.
Orbital benzeneEach carbon atom in benzene tying 3 others using sp2 hybridized orbital forming a planar molecule.Benzene is a symmetrical molecule, hexagonal shape with a bond angle 120oEach C atom has four orbital into the p orbitals. P orbitals overlap will experience suh (overlapping) to form a cloud of electrons as the source of electrons.C. AROMATIC COMPOUNDS heterocyclicAccording to Erich Hückel, a compound that contains five or six-membered ring is aromatic if:• all the constituent atoms lie in a flat (planar)• every atom that form a ring having a 2p orbital• have the pi electrons in the cyclic arrangement of the 2p orbitals as 4n +2 (n = 0, 1, 2, 3, ...)In addition to benzene and its derivatives, there are several other types of compounds exhibit aromatic properties, which have high unsaturation and showed no reactions like alkenes. Benzene homosiklik included in the class of compounds, ie compounds that have only one type of atom in the ring system. There are heterocyclic compounds, are compounds that have more than one type of atom in the ring system, the ring is composed of one or more atoms that are not carbon atoms. For example, pyridine and pirimidina are aromatic compounds such as benzene. In pyridine one CH unit of benzene is replaced by a nitrogen atom sp2 hybridise, and in pirimidina two CH units replaced by nitrogen atoms are sp2 hybridise.Membered heterocyclic compounds of five such as furan, thiophene, pyrrole, and imidazole also includes aromatic compounds.D. TERMS OF AROMATIC COMPOUNDSAromatics Requirements:1. Molecules have cyclic and flat.2. have p orbitals perpendicular to the ring plane (pi electron delocalization allow).3. have p orbitals perpendicular to the ring plane (pi electron delocalization allow)8 siklooktatetraena not aromatic pi electrons.(Fessenden and Fessenden .463-464: 1982).A. Hückel rule
In the year 1931 a German chemist Erich Hückel, suggested that an aromatic compound to be flat, monocyclic (one ring) needs to have as many pi elketron 4N + 2, where n is an integer sebuahn. According to the Hückel rule, a ring with pi electrons as 2,6,10 or 14 can be aromatic, but the ring with 8 or 12 pi electrons, can not be. Siklooktatetraena (with 8 electrons pi) does not comply with Hückel rule for aromaticity.Why the 6 or 10 pi electrons are aromatic, whereas 8 pi electrons are not?In order to be aromatic, all pi electrons must be paired, so it is possible overlapping (overlapping) optimal resulting in delocalization perfect.
If siklooktatetraena flat and has a system similar to pi pi system of benzene, the orbital π1, π2, and π3 will be filled with six pi electrons pi.Dua remaining electrons will each occupy degenerate orbitals and π5 π4 (Hund's rule). Then not all the pi electrons will pair up and will not overlap maksimal.Jadi sikooktatetraena will not be aromatic. (Fessenden and Fessenden .464-464: 1982).Aromatic compounds must meet the following criteria:- Cyclical- Contains a delocalized p electron clouds below and above the plane of the molecule- Double bonds alternate with single bonds- Have a total number of 4N +2 p electrons, where n must bulisal numbers: if the number of electrons in a ring of a cyclic p = 12, then n = 2.5 then instead of aromatic compounds
B. Ion cyclopentadiene
Cyclopentadiene is a conjugated diene and aromatic aromatik.Alasan main reason why not is that one carbon atom is sp3, not sp2.Karbon sp3 has no p orbitals take tuk un pi bond, but when taken one of the hydrogen ions in the cyclopentadiene carbon hidrodisasi will change to sp2 and p orbitals will have that contains a pair of electrons.
Aromatic Aromatic Cation AnionAll the carbon atoms of the cyclopentadiene cation will also be sp2.Is one or both of these ions are aromatic? Each ion has five π molecular orbitals (p orbitals formed from five, one per carbon). Anion cyclopentadiene with six pi electrons (4N +), filling three orbitals and all these pi electrons that are aromatik.Tetapi berpasangan.Maka cation anion it only has four electrons (4N) to fill three orbital.Maka pi electrons is not going all berpasangan.Jadi cation is not aromatic.(Fessenden and Fessenden .465-466: 1982).
please help me!!how to determine whether a compound is an aromatic compound or not?
BalasHapusThe easiest way to determind an aromatic compound or not is to determind the position of the absorption spectrum by the number of protons attached to the ring atom. Later to become aromatic molecule must have p orbital perpendicular to the ring plane to allow for dekolalisation p electrons and all electrons must be paired. The purpose of the valence electron dekolalisation itself is not fixed to one atom position but constantly switching between atoms.
BalasHapusI try to respond
HapusAn aromatic hydrocarbons have a characteristic single bond or a double bond, and the carbon atoms. Configuration 6 carbon atoms in the aromatic compound called benzene rings. Aromatic hydrocarbons can be monocyclic or polycyclic. Aromatic hydrocarbons, usually containing rings of carbon atoms are very stable.
TERMS OF AROMATIC COMPOUNDS Aromatics Requirements:
BalasHapus1. Molecules have cyclic and flat.
2. have p orbitals perpendicular to the ring plane (pi electron delocalization allow).
3. have p orbitals perpendicular to the ring plane (pi electron delocalization allow)8 siklooktatetraena not aromatic pi electrons.USE AND IMPACT benzene in LIFE
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