Organometallic Rhodium(III) and -(I) Complexes with 1,3-Diniethyllumazine(DML). The Crystal Structure of [(η 2 - (O 4 ,N 5 )DML)(η 5 -C 5 Me 5 )ClRh](PF 6 )

• Published in: Zeitschrift für Naturforschung B
• Main Authors: Heilmann, Oliver, Hausen, Hans-Dieter, Kaim, Wolfgang
• Format: Article in Journal/Newspaper
• Language: English
• Published: Walter de Gruyter GmbH 1994
• Subjects: General Chemistry; DML
• Online Access: http://dx.doi.org/10.1515/znb-1994-1117; https://www.degruyter.com/view/journals/znb/49/11/article-p1554.xml; https://www.degruyter.com/document/doi/10.1515/znb-1994-1117/xml; https://www.degruyter.com/document/doi/10.1515/znb-1994-1117/pdf

The crystal structure determination of the new rhodium(III)-complex [(DML)(C 5 Me 5 )ClRh](PF 6 ). DML = 1,3-dimethyllumazine, reveals O 4 ,N 5 coordination of the metal to DML with not very different bond lengths of 213.0(2) pm (Rh-N) and 219.2(2) pm (Rh-O). This result stands in contrast to the previously reported structure of a cationic dihydrobiopterin bound to [Mo(O)Cl 3 ] - which exhibited a very unsymmetrical chelate ar­rangement. Chemical and electrochemical two-electron reduction of the Rh(III) complex led to a very labile Rh(I) species (DML)(C 5 Me 5 )Rh which is distinguished by an intense charge transfer band in the visible. The results confirm the characterization of DML as a weak σ donor/π acceptor ligand with a rather low-lying π* orbital.