TY - JOUR
T1 - Synthesis and characterization of chromium complexes 2-Me 4 CpC 6 H 4 CH 2 (R)NHCrCl 2 and their catalytic properties in ethylene homo- and co-polymerization
AU - Song, Tingting
AU - Tao, Xin
AU - Tong, Xiaobo
AU - Liu, Ning
AU - Gao, Wei
AU - Mu, Xiaoyue
AU - Mu, Ying
N1 - Publisher Copyright:
© 2019 The Royal Society of Chemistry.
PY - 2019
Y1 - 2019
N2 - A series of new half-sandwich secondary amine-coordinated dichlorochromium complexes chelated by 2-(tetramethylcyclopentadienyl)benzylamine ligands, 2-Me 4 CpC 6 H 4 CH 2 (R)NHCrCl 2 [R = i Pr (1), Cy (2), Ph (3), 4-MePh (4), 2,6-Me 2 Ph (5), 2,6-Et 2 Ph (6)], have been synthesized from the reactions of CrCl 3 (THF) 3 with the dilithium salts of the corresponding ligands in THF, followed by the addition of 1/2 eq. of H 2 O to the reaction mixtures. The isolated yields of the chromium complexes were found to increase with the increase in the amount of H 2 O introduced and reach the highest values (66-76%) when 1/2 eq. of H 2 O is added. Attempts to isolate the 2-(tetramethylcyclopentadienyl)benzylamidochromium complexes, 2-Me 4 CpC 6 H 4 CH 2 (R)NCrCl, were not successful. The new dichlorochromium complexes were characterized by IR, 1 H NMR, EPR, and UV/Vis spectroscopy and elemental analyses, and the molecular structures of complexes 1, 5 and 6 were determined by X-ray crystallography. The X-ray crystallographic analysis reveals that these chromium complexes possess a three-legged piano-stool geometry with the amine N atom in a mitered six-membered chelating ring and the two chloride atoms as the legs. Upon activation with AlR 3 and Ph 3 CB(C 6 F 5 ) 4 , complexes 1-6 exhibit reasonable catalytic activity for ethylene polymerization and copolymerization with 1-hexene, producing polyethylenes with moderate to high molecular weights and poly(ethylene-co-1-hexene)s with moderate comonomer incorporation which are typical linear low-density polyethylenes (LLDPE). Complex 4 was found to show higher catalytic activity for ethylene homo- and co-polymerization than other complexes under similar conditions, while complex 3 produced poly(ethylene-co-1-hexene)s with the highest comonomer incorporation.
AB - A series of new half-sandwich secondary amine-coordinated dichlorochromium complexes chelated by 2-(tetramethylcyclopentadienyl)benzylamine ligands, 2-Me 4 CpC 6 H 4 CH 2 (R)NHCrCl 2 [R = i Pr (1), Cy (2), Ph (3), 4-MePh (4), 2,6-Me 2 Ph (5), 2,6-Et 2 Ph (6)], have been synthesized from the reactions of CrCl 3 (THF) 3 with the dilithium salts of the corresponding ligands in THF, followed by the addition of 1/2 eq. of H 2 O to the reaction mixtures. The isolated yields of the chromium complexes were found to increase with the increase in the amount of H 2 O introduced and reach the highest values (66-76%) when 1/2 eq. of H 2 O is added. Attempts to isolate the 2-(tetramethylcyclopentadienyl)benzylamidochromium complexes, 2-Me 4 CpC 6 H 4 CH 2 (R)NCrCl, were not successful. The new dichlorochromium complexes were characterized by IR, 1 H NMR, EPR, and UV/Vis spectroscopy and elemental analyses, and the molecular structures of complexes 1, 5 and 6 were determined by X-ray crystallography. The X-ray crystallographic analysis reveals that these chromium complexes possess a three-legged piano-stool geometry with the amine N atom in a mitered six-membered chelating ring and the two chloride atoms as the legs. Upon activation with AlR 3 and Ph 3 CB(C 6 F 5 ) 4 , complexes 1-6 exhibit reasonable catalytic activity for ethylene polymerization and copolymerization with 1-hexene, producing polyethylenes with moderate to high molecular weights and poly(ethylene-co-1-hexene)s with moderate comonomer incorporation which are typical linear low-density polyethylenes (LLDPE). Complex 4 was found to show higher catalytic activity for ethylene homo- and co-polymerization than other complexes under similar conditions, while complex 3 produced poly(ethylene-co-1-hexene)s with the highest comonomer incorporation.
UR - http://www.scopus.com/inward/record.url?scp=85064161033&partnerID=8YFLogxK
U2 - 10.1039/c9dt00448c
DO - 10.1039/c9dt00448c
M3 - Article
C2 - 30912553
AN - SCOPUS:85064161033
SN - 1477-9226
VL - 48
SP - 4912
EP - 4920
JO - Dalton Transactions
JF - Dalton Transactions
IS - 15
ER -