Modification initiator and modified conjugated diene-based polymer including the same

A method of preparing a modified conjugated diene-based polymer, the method comprising a step (S1) of preparing an active polymer coupled with an alkali metal by polymerization of a conjugated diene-based monomer, or an aromatic vinyl-based monomer with a conjugated diene-based monomer in a hydrocarbon solvent which includes a modification initiator including a compound represented by Formula 1:

• wherein, in Formula 1,
• Y1 and Y2 are each independently M or R15, wherein Y2 is R15 when Y1 is M, and Y2 is M when Y1 is R15,
• M is an alkali metal,
• R1, R2, and R15 are each independently hydrogen;
• an alkyl group having 1 to 30 carbon atoms;
• an alkenyl group having 2 to 30 carbon atoms;
• an alkynyl group having 2 to 30 carbon atoms;
• a heteroalkyl group having 1 to 30 carbon atoms which includes a nitrogen (N), oxygen (O), or sulfur (S) atom;
• a heteroalkenyl group having 2 to 30 carbon atoms which includes an N, O, or S atom;
• a heteroalkynyl group having 2 to 30 carbon atoms which includes an N, O, or S atom;
• a cycloalkyl group having 5 to 30 carbon atoms;
• an aryl group having 5 to 30 carbon atoms;
• or a heterocyclic group having 3 to 30 carbon atoms which includes at least one of N, O, and S atoms,
• R3 is hydrogen,
• R4 is a single bond;
• an alkylene group having 1 to 20 carbon atoms which is substituted or unsubstituted with an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, or an aryl group having 5 to 20 carbon atoms;
• a cycloalkylene group having 5 to 20 carbon atoms which is substituted or unsubstituted with an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, or an aryl group having 5 to 20 carbon atoms;
• or an arylene group having 5 to 20 carbon atoms which is substituted or unsubstituted with an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, or an aryl group having 5 to 20 carbon atoms,
• R5 is an alkyl group having 1 to 30 carbon atoms;
• an alkenyl group having 2 to 30 carbon atoms;
• an alkynyl group having 2 to 30 carbon atoms;
• a heteroalkyl group having 1 to 30 carbon atoms which includes an N, O, or S atom;
• a heteroalkenyl group having 2 to 30 carbon atoms which includes an N, O, or S atom;
• a heteroalkynyl group having 2 to 30 carbon atoms which includes an N, O, or S atom;
• a cycloalkyl group having 5 to 30 carbon atoms;
• an aryl group having 5 to 30 carbon atoms;
• a heterocyclic group having 3 to 30 carbon atoms which includes at least one of N, O, and S atoms;
• a functional group represented by Formula 2;
• or a functional group represented by Formula 3,
• n is an integer selected from 1 to 5, at least one of R5 is the functional group represented by Formula 2 or 3, and a plurality of R5 are the same or different from each other when n is an integer selected from 2 to 5,
• wherein, in Formulae 2 and 3,
• R6 and R10 are each independently an alkylene group having 1 to 20 carbon atoms which is substituted or unsubstituted with an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, or an aryl group having 5 to 20 carbon atoms;
• a cycloalkylene group having 5 to 20 carbon atoms which is substituted or unsubstituted with an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, or an aryl group having 5 to 20 carbon atoms;
• or an arylene group having 5 to 20 carbon atoms which is substituted or unsubstituted with an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, or an aryl group having 5 to 20 carbon atoms,
• R7, R8, and R12 are each independently an alkylene group having 1 to 20 carbon atoms which is substituted or unsubstituted with an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 5 to 10 carbon atoms, or an aryl group having 5 to 20 carbon atoms,
• R9, R11, R13, and R14 are each independently hydrogen;
• an alkyl group having 1 to 30 carbon atoms;
• an alkenyl group having 2 to 30 carbon atoms;
• an alkynyl group having 2 to 30 carbon atoms;
• a heteroalkyl group having 1 to 30 carbon atoms which includes an N, O, or S atom;
• a heteroalkenyl group having 2 to 30 carbon atoms which includes an N, O, or S atom;
• a heteroalkynyl group having 2 to 30 carbon atoms which includes an N, O, or S atom;
• a cycloalkyl group having 5 to 30 carbon atoms;
• an aryl group having 5 to 30 carbon atoms;
• a heterocyclic group having 3 to 30 carbon atoms which includes at least one of N, O, and S atoms;
• an alkenyl group having 2 to 30 carbon atoms which is substituted with an alkyl group having 1 to 10 carbon atoms which includes an alkali metal;
• or an aryl group having 6 to 30 carbon atoms which is substituted with an alkyl group having 1 to 10 carbon atoms which includes an alkali metal,
• X1 and X2 are each independently one selected from N, O, and S atoms, R9 is not present when X1 is an O or S atom, R14 is not present when X2 is an O or S atom, and
• m is an integer of 1 or 2.