Phosphorus-based flame retardant and thermoplastic resin composition including same

A phosphorus-based flame retardant represented by the following Chemical Formula 1:

• wherein in Chemical Formula 1,
• R1 to R3 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 C2 to C40 alkenyl group, a C3 to C40 cycloalkyl group, 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,
• R4 is selected from a C1 to C40 alkyl group, a C2 to C40 alkenyl group, a C3 to C40 cycloalkyl group, 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, each of which comprises at least one substituent capable of forming coordination bonding with the following M,
• M is a metal selected from Group 1, Group 2, Group 3 and transition metals, or a protonated nitrogen base,
• m, n and x are each an integer in a range from 1 to 5, and
• wherein the C1 to C40 alkyl group, the C2 to C40 alkenyl group, the C3 to C40 cycloalkyl group, the heterocycloalkyl group having 3 to 40 nuclear atoms, the C6 to C60 aryl group and the heteroaryl group having 5 to 60 nuclear atoms of R1 to R4 are each independently unsubstituted or substituted with one or more substituents selected from deuterium (D), halogen, a cyano group, a nitro group, a hydroxyl group, an amine group, a carboxyl 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.