Cyclopenta[b]fluorenyl transition metal compound, catalyst composition containing the same, and method of preparing ethylene homopolymer or copolymer of ethylene and α-olefin using the same

1. A transition metal compound represented by Chemical Formula 1 below:

In Chemical Formula 1, M is a Group 4 transition metal in the Periodic Table of Elements;

n is an integer of 1 or 2, each R 1 may be the same or different when n is 2;

R 1 is hydrogen, (C1-C50)alkyl, halo(C1-C50)alkyl, (C3-C50)cycloalkyl, (C6-C30)aryl, (C6-C30)aryl(C1-C50)alkyl, ((C1-C50)alkyl(C6-C30)aryl)(C1-C50)alkyl, —NR a R b , —SiR c R d R e , or 5- through 7-membered N-heterocycloalkyl containing at least one nitrogen atom;

R 2 and R 3 each are independently hydrogen, (C1-C50)alkyl, (C1-C50)alkoxy, halo(C1-C50)alkyl, (C3-C50)cycloalkyl, (C6-C30)aryl, (C6-C30)aryloxy, (C1-C50)alkyl(C6-C30)aryloxy, (C6-C30)aryl(C1-C50)alkyl, ((C1-C50)alkyl(C6-C30)aryl)(C1-C50)alkyl, —NR a R b or —SiR c R d R e ;

R 4 , R 5 , R 10 , R 11 and R 12 each are independently (C1-C50)alkyl, halo(C1-C50)alkyl, (C3-C50)cycloalkyl, (C6-C30)aryl, (C6-C30)aryl(C1-C50)alkyl, ((C1-C50)alkyl(C6-C30)aryl)(C1-C50)alkyl, —NR a R b , or —SiR c R d R e , and R 11 and R 12 may be linked via (C4-C7)alkylene to form a ring;

R 6 , R 7 , R 8 and R 9 each are independently hydrogen, (C1-C50)alkyl, halo(C1-C50)alkyl, (C3-C50)cycloalkyl, (C1-C50)alkoxy, (C6-C30)aryl, (C6-C30)aryl(C1-C50)alkyl, ((C1-C50)alkyl(C6-C30)aryl)(C1-C50)alkyl, (C6-C30)aryloxy, (C1-C50)alkyl(C6-C30)aryloxy, N-carbazolyl, —NR a R b , or —SiR c R d R e , or may be linked to an adjacent substituent via (C1-C5)alkylene to form a ring, and at least one —CH 2 — of the alkylene may be substituted by a hetero atom selected from —O—, —S—, and —NR—, and the alkylene may be further substituted with (C1-C50)alkyl;

aryl of R 1 to R 12 may be further substituted with at least one substituent selected from the group consisting of (C1-C50)alkyl, halo(C1-C50)alkyl, (C1-C50)alkoxy, (C6-C30)aryloxy, (C6-C30)aryl, (C1-C50)alkyl(C6-C30)aryl, and (C6-C30)aryl(C1-C50)alkyl;

R′ and R a to R e each are independently (C1-C50)alkyl or (C6-C30)aryl;

X 1 and X 2 each are independently halogen, (C1-C50)alkyl, (C2-C50)alkenyl, (C3-C50)cycloalkyl (C6-C30)aryl, (C6-C30)aryl(C1-C50)alkyl, ((C1-C50)alkyl(C6-C30)aryl)(C1-C50)alkyl, (C1-C50)alkoxy, (C6-C30)aryloxy, (C1-C50)alkyl(C6-C30)aryloxy, (C1-C50)alkoxy(C6-C30)aryloxy, (C1-C50)alkylidene, —OSiR f R g R h , —SR i , —NR j R k , —PR l R m or dianion bidentate ligand consisting of 60 or less atoms containing N, P, O, S, Si, and halogen, except hydrogen, provided that one of X 1 and X 2 is a dianion bidentate ligand, the other is ignored;

R f to R i each are independently (C1-C50)alkyl, (C6-C30)aryl, (C3-C50)cycloalkyl; and

R j to R m each are independently (C1-C50)alkyl, (C6-C30)aryl, (C6-C30)aryl(C1-C50)alkyl, (C3-C50)cycloalkyl, tri(C1-C50)alkylsilyl, or tri(C6-C30)arylsilyl.

2. The transition metal compound of claim 1 , wherein the transition metal compound is represented by Chemical Formula 2 or 3 below:

In Chemical Formulas 2 and 3, M, R 2 to R 12 , X 1 and X 2 has the same definition as defined in Chemical Formula 1 of claim 1 ; R 21 and R 22 each are independently hydrogen, (C1-C50)alkyl, halo(C1-C50)alkyl, (C3-C50)cycloalkyl, (C6-C30)aryl, (C6-C30)aryl(C1-C50)alkyl, ((C1-C50)alkyl(C6-C30)aryl)(C1-C50)alkyl, —NR a R b , —SiR c R d R e , or 5- through 7-membered N-heterocycloalkyl containing at least one nitrogen atom; aryl of R 1 may be further substituted with at least one substituent selected from the group consisting of halogen, (C1-C50)alkyl, halo(C1-C50)alkyl, (C1-C50)alkoxy, (C6-C30)aryloxy, (C6-C30)aryl, (C1-C50)alkyl(C6-C30)aryl, and (C6-C30)aryl(C1-C50)alkyl; and R a to R e each are independently (C1-C50)alkyl or (C6-C30)aryl.

3. The transition metal compound of claim 2 , wherein it is selected from the compounds below:

M is Ti, Zr or Hf, and X 1 and X 2 each have the same definition as defined in claim 2 .

4. A transition metal catalyst composition for preparing an ethylene homopolymer or a copolymer of ethylene and α-olefin, the transition metal catalyst composition comprising the transition metal compound of claim 1 ; and a cocatalyst selected from an aluminum compound, a boron compound, and a mixture thereof.

5. The transition metal catalyst composition of claim 4 , wherein the transition metal compound and the cocatalyst have a molar ratio of transition metal (M): boron atom (B): aluminum atom (Al) in the range of 1:0˜100:1˜2,000.

6. The transition metal catalyst composition of claim 5 , wherein the transition metal compound and the cocatalyst have a molar ratio of transition metal (M): boron atom (B): aluminum atom (Al) in the range of 1:0.5˜5:10˜500.