Bonding and Structure of Organic Compounds Flashcards
4 main ERAS in the history of organic chemistry
- 1700s History
- Theory of Vitalism
- Against Vitalism
- Structural Theory
1700s HISTORY (2)
- Year
- Scientist
- Event
MID-1700s
- living (blood & synthesized sugar) and non-living substances (natural sugar & minerals) were discovered
1700s
- Torbern Bergman (differentiated the 2 substances)
Theory of Vitalism (1)
- Year
- Scientist
- Event
1810
- Jons Jacob Berzelius
- coined the term “organic”
- said that organic compounds CAN ONLY be synthesized by living matter due to VITAL FORCE
Against Vitalism (3)
- Year
- Scientist
- Event
1816
- Michel-Eugene Chevrul
- made FATTY ACIDS from soap (non-living matter)… soap is made from animal fats
1828
- Friedrich Wohler
- “Father of Organic Chemistry”
- synthesis of UREA from ammonium cyanate (first org synthesis)
1860
- Marcelin Berthelot
- synthesis of organic compounds from C H O N
Structural Theory (7)
- Year
- Scientist
- Event
1858 & 1861
- Friedrich Kekule
- Archibald Couper
- Alexander Butlerov
- Tetravalency of Carbon & basis for STRUCTURAL THEORY
1862
- Emil Fischer
- triple bond in acetylene
1864
- Alexander Brown
- double bond in ethylene
1869
- Wilhelm Korner
- structures of benzenes
1872
- Viktor Meyer
- steric hindrance in organic compounds
1916
- Gilbert Lewis
- explained the nature of covalent compounds
1926
- Erwin Schrodinger
- Werner Heisenberg
- Paul Dirac
- advancement in ATOMIC and MOLECULAR STRUCTURE
STRUCTURAL THEORY
- main definition
“in org chem, atoms form a fixed # of bonds”
ORGANIC COMPOUNDS
_______ compounds
consists of mainly what type of atom
what type of bond
chemical compounds
with CARBON atoms
covalent bonds
Common misconception about ORGANIC MATERIALS
organic materials STILL contain chemicals tho it is widely believed to be purely made of living matter
2 TYPES OF ORGANIC COMPOUNDS
- Natural
- definition (2)
- example (3) - Synthetic
- definition (1)
- Natural
- derived from living things
- isolated from living matter in a laboratory
+ biomolecules
+ phytochemicals
+ secondary metabolites - Synthetic
- made from scratch in a laboratory
2 main properties of CARBON
- Tetravalency
- Catenation
TETRAVALENCY
- How many bonds
- What type of bonds
- With what type of atoms
- Four bonds
- Covalent bonds
- All atoms (including carbon)
CATENATION
- ability to__?
- what does catenation result to?
- ability to form bonds with carbon atoms
- to form chains
3 TYPES of backbone that CARBON can form:
- Linear
- Branched
- Cyclic
3 TYPES of bonds that CARBON can form:
- Single
- Double
- Triple
Who are the TWO (2) authors that proposed tetravalency?
- Friedrich August Kekule
- Archibald Scott Couper
OTHER 5 characteristics of CARBON in terms of:
- melting point
- solubility
- state in room temp
- combustibility
- sensitivity to ___?
- LOW mp
- LIMITED (no) solubility in water
- MOST are liquid; SOME are gas
- combustible
- sensitive to heat
2 TYPES of structural formula
- Expanded
- Condensed
Condensed Formula VS Skeletal Formula
CF
- shows condensed elements into molecules
SF
- a “line-angle” structure
SKELETAL FORMULA
how to draw the ff:
1. Carbon Atoms
2. Hydrogen Atoms
3. Other Atoms
- not drawn (depicted in line ends/bends)
- not drawn IF ATTACHED to a carbon atom
- always drawn
ISOMERS
- 2 types
- Where the WORD came from (2)
- Structural
- Stereoisomers
- ISO = equal ; MER = part
STRUCTURAL ISOMERS (2) VS STEREOISOMERS (1)
Structural
- same molecular formula
- different structural formula
Stereo
- differ in orientation of atoms in space
Other term for structural isomers
Constitutional Isomers
If 2 compounds have different structural formulas despite having the same molecular formula, are they still considered as the same compound?
no
3 TYPES of Structural Isomers
- Skeletal
- Functional Group
- Positional
3 TYPES of Structural Isomers
SKELETAL ISOMER
same….
different….
same functional group
different carbon skeleton
3 TYPES of Structural Isomers
FUNCTIONAL GROUP ISOMERS
________ isomers
different…….
constitutional isomers
different functional groups
3 TYPES of Structural Isomers
POSITIONAL ISOMERS
______ isomers
same….
same….
different…
constitutional isomers
same carbon skeleton
same functional group
different location
DIFFERENTIATE BETWEEN:
- Same compounds
- Different compounds and not isomers
- Different compounds that are constitutional isomers
- Same # of C
Same carbon structure - Different # of C
May be same # of C but different # of bonds - Same # of C
Different carbon structure
Index of Hydrogen Deficiency FORMULA
IHD =
2C + 2 + N - H - X
/
2
X = halogens
Index of Hydrogen Deficiency OTHER TERM
Degree of Unsaturation
3 RULES in IHD
- Double Bond / Ring = 1 IHD
- Triple Bond = 2 IHD
- Always a positive integer
Bond angle present in the ff:
- Linear
- Trigonal Planar
- Tetrahedral
180
120
109.5
*if with lone pairs, bond angles will change acc since stronger repulsion
LEWIS vs KEKULE structures
and which of the 2 is more used in organic compounds
L: electron-dot structures
K: line-bond structures
KEKULA more used
Are bond strength significant in resonance structures?
NO,, if yung changing of bonds yung affected per individual resonance structure
5 rules on RESONANCE STRUCTURES
- individual resonance structures are imaginary
- only pi bonds and non-bonding e- can move around
- resonance forms dont have to be equivalent
- must be valid lewis structures
- the RESONANCE HYBRID is the TRUE STRUCTURE of molecules
In benzene rings, how is RESONANCE STABILITY symbolized?
Arrow na paikot sa loob ng ring
FUNCTIONAL GROUPS
- main function
- 2 characteristics
classify organic compounds REGARDLESS OF size and complexity
- definite arrangement
- characteristic chemical behaviour
“Class of Organic Compound”
- definition
- group of compounds containing the same functional group
Recite all FUNCTIONAL GROUPS
HYDROCARBONS (4)
HETEROATOMS (18)
hydrocarbons - hydrogen and carbon only
heteroatoms - other elements
AROMATIC RING, key features (2)
- has a ring
- all atoms forming the ring are connected to a double bond (OR there are 3 double bonds in strucuture)
4 rules in CONDENSED formulas
- central atoms and those connected to it are written in a group
- carbons in linear backbone are written together
- functional group written as one
- double and triple bonds are always shown
WHICH ARE MORE STABLE?
compounds vs individual atoms
compounds
Common BONDING PATTERNS of the following elements:
- Carbon
- Hydrogen
- Nitrogen
- Oxygen
- Halogens
CARBON - 4
NITROGEN - 3
OXYGEN - 2
HYDROGEN - 1
HALOGEN - 1
2 theories that explain SHARING OF ELECTRONS
- main difference (process of formation)
COVALENT BONDS ARE FORMED FROM:
- Valence Bond Theory - the overlap of atomic orbitals (each with opposite electron spins)
- Molecular Orbital Theory (a mathematical combination of atomic orbitals to form a new set of orbitals: MOLECULAR ORBITAL)
In VALENCE BOND THEORY:
- relationship between AMOUNT OF ORBIT OVERLAP and STRENGHT OF BOND
DIRECT
greater overlap = greater strength
ANTIBONDING vs BONDING molecular orbitals
- what interacts?
- presence of electron density
BONDING
- like phases interact
- increases electron density between nuclei
ANTIBONDING
- opposite phases interact
- no electron density between nuclei
ORBITAL HYBRIDIZATION
- proposed by?
- when
- main definition
- explains what?
- Linus Pauling (1931)
- mathematical mixing of orbitals that are close in energy to generate a set of equivalent HYBRID ORBITALS
- explains the valence bond treatment of bonding in organic molecule with the tetravalent carbon IN RELATION TO GEOMTERY
4 CONSIDERATIONS in writing structures
- Valency of Atoms
- Possible functional groups
- Isomerism
- Degree of hydrogen deficiency
IMPORTANT REMINDER for connecting carbon atoms with bonds
Sa carbon dapat didikit
EXAMPLE of HALOGENS
F, Cl, Br, I, At, Ts
