TY - JOUR
T1 - Chiral palladium(II) complexes bearing tetradentate nitrogen ligands
T2 - Synthesis, crystal structure and reactivity towards the polymerization of norbornene
AU - Abu-Surrah, Adnan S.
AU - Thewalt, Ulf
AU - Rieger, Bernhard
N1 - Funding Information:
The authors thank the DFG (SFB 239, project F11), the BMBF and the Polymer Laboratory of BASF Aktiengesellschaft, Ludwigshafen for generous financial support. A.S.A.-S. would also like to thank the BASF Aktiengesellschaft, Business Unit Catalysts, for a postdoctoral fellowship.
PY - 1999/9/15
Y1 - 1999/9/15
N2 - A synthesis for a series of tetrapodal nitrogen ligands (N,N′-dibenzyl-N,N′-di(quinoline-2-methyl)-1,2-ethylene diamine (DBQED, 1), N,N′-dimethyl-N,N′-di(quinoline-2-methyl)-1,2-ethylene diamine (DMQED, 2), (1R,2R)-(-)-N,N′-di(quinoline-2-methylene) diiminocyclohexane (DQEDC, 3), N,N′-di(quinoline-2-methylene)-1,2-phenylene diimine (DQPD, 4) and for their corresponding neutral and cationic palladium(II) complexes of the types [(1,2,4)PdCl2] (5a, 6a, 7) and [(1,2,3,4)Pd(NCCH3)x](Y)2 (5b, 5c, 6b, 6c, 8, 9), x=0, 2; Y=BF4-, NO3- is reported. The dicationic palladium(II) complex [Pd(DBQED)(NO3)2·H2O] (5c) crystallizes in the monoclinic space groups P21/c (no. 14) with a=11.458(1), b=15.302(1) Å, c=20.644(2) Å, β=99.23(1)° and V=3572.7 Å3, Z=4. All four nitrogen donors are attached to the Pd(II)-center in the chiral and C2-symmetric complex 5c. The two quinoline nitrogen atoms of the more rigid Schiff bases (DQEDC, 3; DQPD, 4) do not coordinate coincidentally to Pd(II). A fluxional coordination behavior is suggested for these quinoline donors, which enables this new complex family to act as catalysts for norbornene polymerization, even when chloride is present as a counter ion. Introduction of an enantiomerically pure trans-1,2-cyclohexyl bridge into the Schiff base ligand systems afforded the formation of partially stereoregular polynorbornene.
AB - A synthesis for a series of tetrapodal nitrogen ligands (N,N′-dibenzyl-N,N′-di(quinoline-2-methyl)-1,2-ethylene diamine (DBQED, 1), N,N′-dimethyl-N,N′-di(quinoline-2-methyl)-1,2-ethylene diamine (DMQED, 2), (1R,2R)-(-)-N,N′-di(quinoline-2-methylene) diiminocyclohexane (DQEDC, 3), N,N′-di(quinoline-2-methylene)-1,2-phenylene diimine (DQPD, 4) and for their corresponding neutral and cationic palladium(II) complexes of the types [(1,2,4)PdCl2] (5a, 6a, 7) and [(1,2,3,4)Pd(NCCH3)x](Y)2 (5b, 5c, 6b, 6c, 8, 9), x=0, 2; Y=BF4-, NO3- is reported. The dicationic palladium(II) complex [Pd(DBQED)(NO3)2·H2O] (5c) crystallizes in the monoclinic space groups P21/c (no. 14) with a=11.458(1), b=15.302(1) Å, c=20.644(2) Å, β=99.23(1)° and V=3572.7 Å3, Z=4. All four nitrogen donors are attached to the Pd(II)-center in the chiral and C2-symmetric complex 5c. The two quinoline nitrogen atoms of the more rigid Schiff bases (DQEDC, 3; DQPD, 4) do not coordinate coincidentally to Pd(II). A fluxional coordination behavior is suggested for these quinoline donors, which enables this new complex family to act as catalysts for norbornene polymerization, even when chloride is present as a counter ion. Introduction of an enantiomerically pure trans-1,2-cyclohexyl bridge into the Schiff base ligand systems afforded the formation of partially stereoregular polynorbornene.
KW - Chirality
KW - Crystal structure
KW - Norbornene polymerization
KW - Palladium(II) polymerization catalysts
KW - Schiff bases
KW - Tetradentate nitrogen ligands
UR - http://www.scopus.com/inward/record.url?scp=0001946275&partnerID=8YFLogxK
U2 - 10.1016/S0022-328X(99)00273-9
DO - 10.1016/S0022-328X(99)00273-9
M3 - Article
AN - SCOPUS:0001946275
SN - 0022-328X
VL - 587
SP - 58
EP - 66
JO - Journal of Organometallic Chemistry
JF - Journal of Organometallic Chemistry
IS - 1
ER -