Forschung/Research

Studies of group 15 element compounds comprise investigations on

  • Search for routes to primary, secondary and tertiary 2-arsino- and 2-phosphino-anilines and –phenols and to 2-hydroxy-biaryl-2´-phosphines.
  • Studies of the ambident reactivity of above compounds at E (As, P), X (N, O) or at both, E and X, allowing access to
    • E-alkylation, BH3-addition, in some cases O…H-E+ protonation and X-acylation,
    • P- or O-hybrid or P,O-chelate-transition metal complexes,
    • variously P- and aryl-substituted (P^O)Ni-chelate (pre)catalysts for moisture tolerant oligo- and/or polymerization of ethylene to linear and copolymerization with α-olefins (also with remote functional groups) to sparingly branched products,
    • acyclic and heterocyclic E-C=N-compounds (from E-secondary precursors) and
    • E=C-N- and E=C-O-compounds (from E-primary precursors), stabilized by inclusion of the dicoordinated As or P atom into aromatic  or delocalized 3-center 4-electron p-bond systems, the latter requiring additional steric protection.
  • Research on phosphino amino acids was started after replacing education in classic chemistry by biochemistry in Greifswald and concerned
    • initially phospha-“Mannich” condensations of H2P-arylOR (R = H, Alk), CH2O and amino acids in cooperation with A. Karasik (Kazan), yielding various types of acyclic and heterocyclic phosphino amino acids, some used as ligands in Pd and Pt-complexes,
    • then condensations of Ph2PH with glyoxylic acid hydrate to phosphinoglycolic acids and, in the presence of primary amines, to phosphinoglycines, kinetically rather unstable, but like phosphino acetic acid useful as ligand precursors for Ni-catalyzed ethylene oligomerizations,
    • heterocyclic α-phosphino amino acids (phosphaprolines), from phosphinoethylamines and α-keto-carboxylic acids or via alkylphosphino-bis(glycines).

Studies of group 14 element compounds comprise some investigations on

  • 2-hydroxyaryl-silanes, di-, tri- and polysilanes and  
  • R-Si-X species (X = Cl, O, N), generated by thermolytic cleavage of chloro-, alkoxy- or amino-substituted disilanes and trapped with 1,3-dienes or (di)heterodienes to give RXSi(X-CR=CR-Y) heterocycles X, Y = O, NR´, CH2; R = H or alk, R´= alk),
  • focussed later, after some cooperation with M. Lappert (B. Gehrhus) on N-heterocyclic silylenes, on
  • syntheses of sterically and p-stabilized N-E(II)-N compounds with E = Ge, Sn and C,
  • transition metal complexes of germylenes and carbenes and
  • effects of carbo- and heterocyclic annulation on the donor/acceptor properties of E(II).

Cooperation partners

The research would not have been possible without cooperation and great support by many colleagues and engaged work of my coworkers – all of whom my sincere thanks. The cooperation partners and coworkers are mentioned as (co)authors in the corresponding publications and listed up below.

  • T. Veszpremi, L. Nyulaszi (1987-2015, TU Budapest), theoretical and PES studies
  • M. Lappert, B. Gehrhus (1993-96, Brighton), N-heterocyclic silylenes
  • R. Kadyrov (1988, 1995, Kazan), 2-hydroxy(bi)arylphosphines
  • W. Keim (Aachen, 1996-2000), Ni-catalyzed ethylene oligo- and polymerization
  • H.-F. Klein (1997-2000, Darmstadt), phosphinophenol(ate) Ni-complexes
  • A. A. Karasik, O. G. Sinyashin (2000, 2020), 2-RO-arylphosphinomethyl amino acids (R=H, Alk)
  • D. Yakhvarov (2000, 2007, 2011-20, Kazan), phosphinophenol esters, phosphinoglycolates and phosphinoglycines, Ni-catalyzed poly- or oligomerization
  • C.-Y. Guo (2007/8, Bejing), (P^O)Ni-catalyzed polymerization and copolymerization
  • R. K. Bansal, Neelima Gupta (1996-2001, 2008, Jaipur), metal complexes of N-bridgehead heterocyclic anellated diazaphospholes, studies on 1,3-benzazaphospholes
  • P. G. Jones (1996-2020, TU Braunschweig), many crystal structure analyses (70 common publications)
  • C. Schulzke (2013-2020, Greifswald), crystal structure analyses
  • further crystal structure analyses by  M. Köckerling (Rostock), A. Spannenberg (Rostock), P. Mayer and K. Karaghiosoff (München), U. Flörke (Paderborn), I. A. Litvinov (Kazan), D. Stalke (Würzburg), R. Boese (Essen), H.-D. Hausen and M. Niemeyer (Stuttgart)

The research results, including those of my PhD thesis and some contributions to research of other groups were presented in ca. 210 publications, 23 patents and >170 lectures and posters.