The new pyrrolyl-linked pincer-type ligand, [C(4)H(2)NH(2-CH(2)NH(t)Bu)(5-CH(2)NMe(2))] (1), that has been employed conveniently in high yield by treatment of (2-t-butylaminomethyl)pyrrole with 1 equiv of formaldehyde and dimethylamine hydrochloride each in diethylether and its corresponding aluminum derivative, [C(4)H(2)N(2-CH(2)NH(t)Bu)(5-CH(2)NMe(2))]AlH(2) (2), that has been generated from Me(3)N.AlH(3) using diethylether as a solvent are described. Furthermore, reactions of 2 with 2 equiv of either 1,3-diphenylpropane-1,3-dione in diethylether or phenyl thioisocyanate in dichloromethane interestingly formed [C(4)H(2)N(2-CH(2)NH(t)Bu)(5-CH(2)NMe(2))]Al(PhCOCHCOPh)(2) (3) and [C(4)H(2)N(2-CH(2)NH(t)Bu)(5-CH(2)NMe(2))]Al(SCHNPh)(2) (4), respectively, following deprotonation or hydroalumination reaction kinetics under a dry nitrogen environment. All of the compounds have been subjected to the X-ray diffraction technique in the solid state as well as characterized by NMR spectra.
A strategy to synthesize branched polyketoesters from the carbonylative polymerization of bifunctional α,ω-alkenols such as 10-undecen-1-ol is presented. This strategy hinges on the competitive application of two related catalytic manifolds, alternating alkene/CO copolymerization, and alkene hydroesterification, which share a common metal acyl intermediate. Small molecule model studies of cationic Pd-catalyzed alkene carbonylation in the presence of alcohols demonstrate that the relative rates of ketone formation (through alternating alkene/CO insertion) and ester formation (through metal acyl alcoholysis) can be tuned across a wide range through judicious bis(phosphine) ligand design. Carbonylative polymerization of 10-undecen-1-ol with a (dppp(3,5-CF 3 ) 4 )Pd(OTs) 2 catalyst (dppp(3,5-CF 3 ) 4 = 1,3-bis[bis[3,5-bis(trifluoromethyl)phenyl]-phosphino]propane) led to the formation of high molecular weight polyketoesters with intermediate dispersity (M n > 20,000 g/mol, D̵ = 2.6) and a ketone/ester microstructure ratio of approximately 1:2. In these polymerization reactions, deploying electron-deficient bis(phosphines) to suppress deleterious alkene isomerization was the key to accessing the high molecular weight polymer. Further, terpolymerization reactions of 1-hexene/10-undecen-1-ol/CO or 1-fluoro-10-undecene/10-undecen-1-ol/CO by (dppp(3,5-CF 3 ) 4 )Pd(OTs) 2 were also successful. This proof of concept polymerization unlocks access to tunable polymer microstructures without extensive postpolymerization treatment.
A series of Cu(II) compounds containing neutral multi‐dentate ligand [2,6‐diisopropylphenyl]‐bis[(1‐H‐pyrazol‐1‐yl)methyl]amine (L1) and pyrazole dimethoxethyl ligand [(1‐H‐pyrazol‐1‐yl)methyl]‐bis(2‐methoxyethyl)amine (L2) were synthesized. Reactions of L1 and L2 with copper(II) chloride generate L1CuCl2 (1) and L2CuCl2 (2), respectively. Compounds 1 and 2 have been characterized by elemental analysis and X‐ray single crystal diffractometry. The effects of compounds 1 and 2 on the cell viability of various human cancer cells (including A549, COLO 205, HT‐29, Hep3B, HepG2, Huh7, and PCL5 cells) were investigated. The results indicate that compound 2 has a strong inhibitory effect on cell growth in human colorectal carcinoma cells (COLO 205 cells and HT‐29 cells).
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