Frank Schaper

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The in situ generation of 3-diazonium cations from 3-aminopyridine and their subsequent stability under experimental conditions used for electrografting of pyridine groups were investigated by spectroscopy and electrochemistry. UV spectroscopy revealed the rapid kinetics for the reaction of 3-aminopyridine with sodium nitrite in HCl to form the(More)
Ligands in which multiple metal-binding domains are linked by a metal-containing moiety rather than a conventional organic group are described as "expanded ligands". The use of 4,4'-difunctionalised {Ru(tpy)(2)} units provides a linear spacer between metal-binding domains and we have extended this motif to expanded ligands containing two carboxylic acid(More)
Diketimine ligands bearing N-benzyl, N-9-anthrylmethyl and N-mesitylmethyl substituents (nacnac(Bn)H, nacnac(An)H, and nacnac(Mes)H) were prepared from condensation of the amine with either acetyl acetone or its ethylene glycol monoketal. Chlorination with N-chlorosuccinimide in the 3-position yielded Clnacnac(Bn)H and Clnacnac(An)H. The ligands were(More)
Stereocontrolled coordination-insertion polymerization of rac-lactide remains a catalytic challenge despite the large number of studies and the successful marketing of polylactide as a disposable plastic. Although a number successful catalysts have been proposed, a system re-uniting high stereoselectivity with high activity and chemical robustness remains(More)
N,N'-Dibenzyl diketiminate copper isopropanolate, (nacnac(Bn)CuOiPr)(2), polymerizes rac- and S,S-lactide in the presence or absence of isopropanol as a chain-transfer reagent with very high activity (k(2) = 32 M(-1) s(-1)), narrow polydispersities and without evidence of side reactions such as transesterification, epimerization or catalyst decomposition.
A series of chiral ansa-magnesocene complexes with dimethylsilanediylor ethanediyl-bridged, substituted cyclopentadienyl or indenyl ligands, prepared in form of their THF adducts, has been structurally characterized by diffractometric crystal structure determination and by NMR studies in solution. The hapticities of the ring ligands vary between h and h ,(More)
Diketimines N,N'-dibenzyl-2-amino-4-imino-pent-2-ene (1), S,S-N,N'-di(phenylethyl)-2-amino-4-imino-pent-2-ene (2), N,N'-bis(3,4,5-trimethoxyphenylmethyl)-2-amino-4-imino-pent-2-ene (3), N,N'-bis(pentafluorophenylmethyl)-2-amino-4-imino-pent-2-ene (4) and N,N'-diisobutyl-2-amino-4-imino-pent-2-ene (5) react with CuOtBu in the presence of(More)
Manganese(III) complexes of tetradentate diphenolate-diamino (NNOO(2-)) ligands were prepared from aerobic reaction of MnCl2 with the respective ligands in basic methanolic solution. Methoxide complexes (NNOO)Mn(OMe)(MeOH)0-1 were obtained for three ligands, while others only provided the respective chloride complexes (NNOO)Mn(Cl)(MeOH). Complexes were(More)
Cy(3)PCuMe (1) undergoes reversible ligand redistribution at low temperature in solution to form the tight ion pair [Cu(PCy(3))(2)][CuMe(2)] (3). The structure of 3 was assigned on the basis of (i) the stoichiometry of the 1 = 3 equilibrium, (ii) the observation of a triplet for the PCy(3) C1 (13)C NMR resonance due to virtual coupling to two (31)P nuclei,(More)