Pyridine-Derived N-Heterocyclic Carbenes: An Experimental and Theoretical Evaluation of the Bonding in and Reactivity of Selected Normal and Abnormal Complexes of Nickel(II) and Palladium(II)
摘要:
We report a thorough investigation of a series of isomeric complexes with the general formula trans-(pyridylidene)M(PPh3)(2)Cl (M = Pd, Ni). For the first time, a systematic comparison of normal, abnormal, and remote bonding modes is presented. X-ray structural and C-13 NMR data indicate the importance of carbenoid mesomeric contributions in their compound class.. The catalytic performance of the palladium complexes trans-(pyridylidene)Pd(PPh3)(2)Cl as precursors in Suzuki-Miyaura-type cross-coupling suggests a correlation of remote bonding with catalyst robustness and effectivity. When metal precursors M(PPh3)(4) are reacted with 2,4-dichloropyridinium salts, preferential formation of remote carbene complexes occurs and indications are that electronic parameters rather than steric influences are responsible for the observed selectivity. Calculations at the BP86/TZ2P level of theory support interpretation of the results.
Pyridine-Derived N-Heterocyclic Carbenes: An Experimental and Theoretical Evaluation of the Bonding in and Reactivity of Selected Normal and Abnormal Complexes of Nickel(II) and Palladium(II)
摘要:
We report a thorough investigation of a series of isomeric complexes with the general formula trans-(pyridylidene)M(PPh3)(2)Cl (M = Pd, Ni). For the first time, a systematic comparison of normal, abnormal, and remote bonding modes is presented. X-ray structural and C-13 NMR data indicate the importance of carbenoid mesomeric contributions in their compound class.. The catalytic performance of the palladium complexes trans-(pyridylidene)Pd(PPh3)(2)Cl as precursors in Suzuki-Miyaura-type cross-coupling suggests a correlation of remote bonding with catalyst robustness and effectivity. When metal precursors M(PPh3)(4) are reacted with 2,4-dichloropyridinium salts, preferential formation of remote carbene complexes occurs and indications are that electronic parameters rather than steric influences are responsible for the observed selectivity. Calculations at the BP86/TZ2P level of theory support interpretation of the results.
Pyridine-Derived N-Heterocyclic Carbenes: An Experimental and Theoretical Evaluation of the Bonding in and Reactivity of Selected Normal and Abnormal Complexes of Nickel(II) and Palladium(II)
作者:Elzet Stander-Grobler、Oliver Schuster、Greta Heydenrych、Stephanie Cronje、Evangeline Tosh、Martin Albrecht、Gernot Frenking、Helgard G. Raubenheimer
DOI:10.1021/om100431u
日期:2010.11.22
We report a thorough investigation of a series of isomeric complexes with the general formula trans-(pyridylidene)M(PPh3)(2)Cl (M = Pd, Ni). For the first time, a systematic comparison of normal, abnormal, and remote bonding modes is presented. X-ray structural and C-13 NMR data indicate the importance of carbenoid mesomeric contributions in their compound class.. The catalytic performance of the palladium complexes trans-(pyridylidene)Pd(PPh3)(2)Cl as precursors in Suzuki-Miyaura-type cross-coupling suggests a correlation of remote bonding with catalyst robustness and effectivity. When metal precursors M(PPh3)(4) are reacted with 2,4-dichloropyridinium salts, preferential formation of remote carbene complexes occurs and indications are that electronic parameters rather than steric influences are responsible for the observed selectivity. Calculations at the BP86/TZ2P level of theory support interpretation of the results.
Quinolin-4(1<i>H</i>)-imines are Potent Antiplasmodial Drugs Targeting the Liver Stage of Malaria
作者:Tiago Rodrigues、Filipa P. da Cruz、Maria J. Lafuente-Monasterio、Daniel Gonçalves、Ana S. Ressurreição、Ana R. Sitoe、Maria R. Bronze、Jiri Gut、Gisbert Schneider、Maria M. Mota、Philip J. Rosenthal、Miguel Prudêncio、Francisco-Javier Gamo、Francisca Lopes、Rui Moreira
DOI:10.1021/jm400246e
日期:2013.6.13
We present a novel series of quinolin-4(1H)-imines as dual-stage antiplasmodials, several-fold more active than primaquine in vitro against Plasmodium berghei liver stage. Among those, compounds 5g and 5k presented low nanomolar IC50 values. The compounds are metabolically stable and modulate several drug targets. These results emphasize the value of quinolin-4(1H)-imines as a new chemotype and their suitable properties for further drug development.