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Synthesis, Structure, and Properties of Osmium Complexes Containing [Os(′S 4 ′)] and [Os(′S 2 ′) 2 ] Fragments (′S 4 ′ 2− = 1,2‐Bis(2‐mercaptophenylthio)ethane(2−), ′S 2 ′ 2− = 1,2‐Benzenedithiolate)
Author(s) -
Sellmann Dieter,
Hennige Andreas C.,
Heinemann Frank W.
Publication year - 1998
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/(sici)1099-0682(199806)1998:6<819::aid-ejic819>3.0.co;2-m
Subject(s) - osmium , chemistry , thioether , intramolecular force , ligand (biochemistry) , sulfur , oxidation state , redox , ethylene , dissociation (chemistry) , octahedron , stereochemistry , molecule , medicinal chemistry , denticity , crystallography , crystal structure , ruthenium , inorganic chemistry , metal , organic chemistry , catalysis , biochemistry , receptor
In search for osmium complexes with sulfur‐dominated coordination spheres that potentially bind and activate or stabilize nitrogenase relevant small molecules, several osmium−sulfur complexes containing 1,2‐bis(2‐mercaptophenylthio)ethane(2−) (′S 4 ′ 2− ) and benzenedithiolate (′S 2 ′ 2− ) ligands were synthesized. [Os II (PR 3 ) 2 (′S 4 ′)] [R = Ph ( 1 ), Et ( 2 )], [Os IV (PR 3 ) 2 (′S 2 ′) 2 ] [R = Et ( 3 ), Pr( 4 ), Me( 5 ), Ph( 6 )], [Os IV (PCy 3 )(′S 2 ′) 2 ] ( 7 ), (PHCy 3 )[Os III (′S 2 ′) 2 ] ( 8a ), (NMe 4 )[Os III (′S 2 ′) 2 ] ( 8b ), and (NBu 4 ) 2 [Os IV (′S 2 ′) 3 ] ( 9b ) were obtained in reactions starting from commercially available osmium compounds and the sulfur and phosphane ligands. The presence or absence of reducing solvents strongly influenced these reactions. Octahedral ( 3 ), ( 4 ), and (PHCy 3 ) 2 [Os IV (′S 2 ′) 3 ] ( 9a ) were characterized by X‐ray structure analysis, leading to the conclusion that despite the high oxidation state of the osmium centers, innocent dithiolate ligands are present. The stabilization of the Os IV centers is traced back to S→M π donation. Close inspection of 1 and 2 revealed a large influence of the phosphane ligands on the stability of Os II thioether complexes. While 1 is reasonable stable, 2 readily gives 3 and ethylene via intramolecular ′S 4 ′ 2− ligand reduction and Os II I→ Os IV oxidation. UV‐Vis spectra of 3 − 5 indicate phosphane dissociation in solution leading to pentacoordinate [Os(PR 3 )(′S 2 ′) 2 ] complexes. This was confirmed by the synthesis of pentacoordinate [Os(PCy 3 )(′S 2 ′) 2 ] ( 7 ).