Phosphorous oligomer, polyester resin and thermoplastic resin composition comprising same

A phosphorus containing oligomer represented by the following Chemical Formula 1:

• wherein in Chemical Formula 1,
• A and A′ are the same as or different from each other, and are each independently selected from the group consisting of a C1 to C40 alkylene group, a C2 to C40 alkenylene group, a C2 to C40 alkynylene group, a C3 to C40 cycloalkylene group, a heteroalkylene group having 1 to 40 nuclear atoms, a heterocycloalkylene group having 3 to 40 nuclear atoms, a C6 to C60 arylene group, and a heteroarylene groups having 5 to 60 nuclear atoms, each of which are independently unsubstituted or substituted with one or more substituents selected from:
• the group consisting of deuterium (D), halogen, a cyano group, a nitro group, a C1 to C40 alkyl group, a C6 to C60 aryl group, and a heteroaryl group having 5 to 60 nuclear atoms, and when the substituents are plural in number, the substituents are the same as or different from each other,
• m is an integer in a range from 1 to 10, and
• n is an integer in a range from 2 to 50.