Phophorus containing monomer or oligomer, polyester resin comprising same, and thermoplastic resin composition

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

• wherein in Chemical Formula 1, A is selected from 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 group having 5 to 60 nuclear atoms,
• X1 and X2 are the same as or different from each other, and are each independently selected from O, S and NR,
• when R is plural in number, R's are the same or different from each other, and are each independently selected from hydrogen, a C1 to C40 alkyl group, a C3 to C40 cycloalkyl group, a heteroalkyl group having 1 to 40 nuclear atoms, a heterocycloalkyl group having 3 to 40 nuclear atoms, a C6 to C60 aryl group, and a heteroaryl group having 5 to 60 nuclear atoms,
• Y1 and Y2 are the same as or different from each other, and are each independently selected from a C1 to C40 alkylene 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 group having 5 to 60 nuclear atoms,
• Z1 and Z2 are the same as or different from each other, and are each independently selected from hydrogen, a hydroxyl group, a C1 to C40 alkyl group, a C3 to C40 cycloalkyl group, a heteroalkyl group having 1 to 40 nuclear atoms, a heterocycloalkyl group having 3 to 40 nuclear atoms, a C6 to C60 aryl group, and a heteroaryl group having 5 to 60 nuclear atoms,
• n is an integer in a range of 1 to 50,
• the alkylene group, the alkenylene group, the alkynylene group, the cycloalkylene group, the heteroalkylene group, the heterocycloalkylene group, the arylene group and the heteroarylene group of A, Y1, and Y2, and the alkyl group, the cycloalkyl group, the heteroalkyl group, the heterocycloalkyl group, the aryl group and the heteroaryl group of R, Z1, and Z2 are each independently unsubstituted or substituted with one or more substituents selected from 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.