0000000001302917
AUTHOR
Karl W. Törnroos
Syntheses, crystal structures and magnetic properties of copper(II) polynuclear and dinuclear compounds with 2,3-bis(2-pyridyl)pyrazine (dpp) and pseudohalide as ligands
Abstract The preparation, crystal structures and magnetic properties of four heteroleptic copper(II) complexes with 2,3-bis(2-pyridyl)pyrazine (dpp) and azide, cyanate or thiocyanate as ligands are reported, [Cu(dpp)(N3)2]n (1), [Cu(dpp)(NCO)2]n (2), [Cu(dpp)(NCS)2]2 (3) and [Cu(H2O)(dpp)(NCS)2]2·2H2O (4). Compounds 1 and 2 are isomorphous, triclinic, space group P1, and consist of mononuclear building blocks featuring copper atoms with close to square planar coordination geometries. The mononuclear units are, however, associated into chains through weak axial Cu–N bonds formed by end-on asymmetrically bridging azido/cyanato groups and by pyridyl nitrogen atoms. Taking these contacts into a…
Asymmetric synthesis of chloroisothreonine derivatives via syn-stereoselective Mannich-type additions across N-sulfinyl-α- chloroimines
Mannich-type reactions of O-Boc glycolic esters across chiral N-sulfinyl-α-chloroaldimines resulted in the efficient and syn-stereoselective synthesis of new γ-chloro-α-hydroxy-β-amino esters (dr > 99:1). The α-coordinating ability of the chlorine atom was of great importance for the diastereoselectivity of the Mannich-type reaction and overruled the chelation of the sulfinyl oxygen with the lithium ion of the incoming E-enolate in the transition state model. These novel chloroisothreonine derivatives proved to be excellent building blocks in asymmetric synthesis of novel syn-β,γ-aziridino-α-hydroxy esters and biologically relevant trans-oxazolidinone carboxylic esters.
Rare-earth metal bis(tetramethylaluminate) complexes supported by a sterically crowded triazenido ligand
Complexes [NNN]Ln(AlMe(4))(2) (Ln = Y, La, Nd, Lu) bearing the sterically demanding aryl-substituted triazenido ligand [(Tph)(2)N(3)] (Tph = [2-(2,4,6-iPr(3)C(6)H(2))C(6)H(4)]) can be obtained from homoleptic complexes Ln(AlMe(4))(3) in moderate yields, both via protonolysis with [(Tph)(2)N(3)]H and a salt metathesis reaction pathway utilizing [(Tph)(2)N(3)]K. In the solid state the Y and Lu derivatives are isostructural, with both tetramethylaluminate groups coordinated in an eta(2) fashion, while one of the [AlMe(4)] ligands of the Nd derivative features a distorted eta(2) coordination mode. Due to the high affinity of the triazenido ligand toward the more Lewis-acidic and harder aluminiu…
CCDC 977961: Experimental Crystal Structure Determination
Related Article: Gert Callebaut, Filip Colpaert, Melinda Nonn, Loránd Kiss, Reijo Sillanpää, Karl W. Törnroos, Ferenc Fülöp, Norbert De Kimpe, Sven Mangelinckx|2014|Org.Biomol.Chem.|12|3393|doi:10.1039/C4OB00243A
CCDC 977962: Experimental Crystal Structure Determination
Related Article: Gert Callebaut, Filip Colpaert, Melinda Nonn, Loránd Kiss, Reijo Sillanpää, Karl W. Törnroos, Ferenc Fülöp, Norbert De Kimpe, Sven Mangelinckx|2014|Org.Biomol.Chem.|12|3393|doi:10.1039/C4OB00243A
CCDC 977960: Experimental Crystal Structure Determination
Related Article: Gert Callebaut, Filip Colpaert, Melinda Nonn, Loránd Kiss, Reijo Sillanpää, Karl W. Törnroos, Ferenc Fülöp, Norbert De Kimpe, Sven Mangelinckx|2014|Org.Biomol.Chem.|12|3393|doi:10.1039/C4OB00243A