Syntheses and Structures of Octamethylmetallocenes of Osmium

• Published in: Journal of inorganic and organometallic polymers and materials 2014-01, Vol.24 (1), p.95-100
• Main Authors: Ochoa, Elizabeth M., Watson, Alex W., Fagnan, Erin N., Pike, Robert D., Watson, Eric J.
• Format: Article
• Language: English
• Subjects: Bonding; Chemistry; Chemistry and Materials Science; Equivalence; Ethanol; Ethyl alcohol; Hydrates; Inorganic Chemistry; Organic Chemistry; Polymer Sciences; Refluxing; Sodium; Zinc
• ISSN: 1574-1443; 1574-1451
• DOI: 10.1007/s10904-013-9930-x

The reaction of sodium hexachloroosmate(IV) hydrate with five equivalents of tetramethylcyclopentadiene (C 5 Me 4 H 2 ) in refluxing ethanol yielded the novel coordination compound bis(tetramethylcyclopentadienyl)chloroosmocinium(IV) hexachloroosmate, [( η 5 -C 5 Me 4 H) 2 OsCl] 2 [OsCl 6 ] ( 1 ). Compound 1 has been characterized by NMR spectroscopy, elemental analysis and single-crystal X-ray diffraction. The cationic complex of 1 [( η 5 -C 5 Me 4 H) 2 OsCl] + , adopts a bent geometry with a ring centroid-osmium-ring centroid angle of 146.2° and an eclipsed conformation of its two tetramethylcyclopentadienyl rings. The addition of zinc powder to sodium hexachloroosmate(IV) hydrate and five equivalents of tetramethylcyclopentadiene in refluxing ethanol produced the known compound, bis(tetramethylcyclopentadienyl)osmium, ( η 5 -C 5 Me 4 H) 2 Os ( 2 ). The crystal structure of 2 has been determined and it reveals an eclipsed arrangement of the tetramethylcyclopentadienyl rings in the solid state. The average Os–C ring bond length in octamethylosmocene 2 (2.187 Å) is in accordance with corresponding bond lengths in osmocene, ( η 5 -C 5 H 5 ) 2 Os (2.19 Å) and decamethylosmocene, ( η 5 -C 5 Me 5 ) 2 Os (2.18 Å).