What Are Conjugated Antibodies?

The conjugated effect, also known as the delocalized effect, refers to an electronic effect in a conjugated system that changes the distribution of electrons (or p electrons) in the system due to the interaction between atoms. Where substituents on the conjugate system can reduce the -electron cloud density of the system, these groups have an electron-withdrawing conjugation effect, represented by -C, such as -COOH, -CHO, -COR; The base energy increases the -electron cloud density of the conjugate system, so these groups have an electron-donating conjugate effect, which is represented by + C, such as -NH2, -R, -OH. ^[1]

H ₂ C = CH ₂ ,

Transmission along the conjugate system is not limited by distance.

Conjugate effect, the change of molecular properties caused by the formation of conjugated bond is called conjugate effect. The conjugation effect is mainly manifested in two aspects.

Conjugation energy : As a result of forming a conjugated bond, the energy of the system is reduced, and the molecule is stable. For example, CH ₂ = CH-CH = CH ₂ conjugated molecules, due to the interaction of the bond and the bond, the total energy of the molecule is reduced, that is, the energy of the CH ₂ = CH-CH = CH ₂ molecule is The sum of the energy of an unconjugated CH ₂ = CH ₂ molecule is low. The lower value is called the conjugate energy.

Bond length : From the point of view of the electron cloud, the more electron clouds overlap between given atoms, the higher the density of the electron cloud, the stronger the two atoms are combined, the shorter the bond length, and the conjugate The generation of the bond makes the distribution of the electron cloud tend to be equalized, which results in the shortening of the single bond bond length and the double bond bond length in the conjugated molecule.

Conjugate effect is

"Conjugate effect is stable" is one of the most basic principles of organic chemistry.

Normal conjugation effect

Also known as - conjugate. Means more than two

Induced effect

Induction effect refers to the introduction of an atom or group into an organic molecule, which causes a bond electron cloud in the molecule.

Induced effect

The phenomenon that the density distribution changes and thus chemical bonds are polarized is called the induced effect. Induction effect In organic compound molecules, due to the influence of different electronegative substituents (atoms or atomic groups), the density of the bonding electron cloud in the entire molecule is shifted to a certain direction. This effect is called induction effect. The induction effect is characterized by the electron cloud migration passing along the bond and weakening or disappearing as the carbon chain grows. For example, acetic acid is a weak acid (pKi = 4.76). The introduction of a chlorine atom, which is more electronegative than hydrogen, into the -carbon atom in the acetic acid molecule can shift the electron cloud of the entire molecule to the chlorine atom, resulting in an increase in the hydroxyl The protonation of the hydrogen atom in the middle makes monochloroacetic acid a strong acid (pKi = 2.86, which is stronger than acetic acid). When comparing the induced effects of various atoms or groups of atoms, hydrogen atoms are often used as a standard. Atoms or atomic groups with stronger electron attraction (larger electronegativity) than hydrogen atoms (such as -X (x represents halogen), -OH, -NO ₂ , -CN, etc.) have an electron-withdrawing induction effect (negative induction effect ), Denoted by -I, the electron cloud of the entire molecule is biased toward substituents. An atom or group of atoms (such as an alkyl group) that has a weaker ability to attract electrons has an electron-inducing effect (positive induction effect). It is represented by I, and the electron cloud of the entire molecule deviates from the substituent. In the induction effect, the arrow is generally used to indicate the direction of electron movement, which indicates that the distribution of the electron cloud has changed. Induction effect is a short-range electronic effect. Generally, the effect of three chemical bonds is small.

Similarities and differences between induced effects and conjugate effects

(1) Difference

Induction effect: bond exists; the polarity of the bond is changed by the difference in electronegativity between atoms to move the entire molecular electron cloud; it is a short-range effect, which generally disappears after 3 carbon atoms; the polarization change is One direction.
Conjugate effect: It exists in conjugate system; it is transmitted along the conjugate chain through the motion of electrons; the strength is generally not affected by the length of the conjugate chain, which is a long-distance electronic effect; the polarities alternate.

(2) Similarities

Both have electron-withdrawing and electron-repelling effects.

Usually when discussing the induced effect and the conjugate effect, they are usually discussed separately, but sometimes there is both an induced effect and a conjugate effect in a molecule, they affect each other and restrict each other. ^[1]