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Title: Thermal fragmentation of acyl thiolato complexes to reactive metal sulfido intermediates. Structure of Ru([eta][sup 6]-SC[sub 3]Me[sub 3]COMe)(PPh[sub 3])[sub 2]

Journal Article · · Organometallics; (United States)
DOI:https://doi.org/10.1021/om00001a043· OSTI ID:6602400

In this study we have examined the thermal fragmentation of acyl thiolate complexes of the type (ring)M(SC[sub 3]Me[sub 3]COMe). While the (cymene)Ru derivative only gave insoluble materials, the thermolysis of the corresponding osmium compound, (cymene)Os(SC[sub 3]Me[sub 3]COMe) (2), proved very informative. Here it was established that the tetramethylfuran is indeed released prior to formation of the free cymene. Furthermore, two intermediates were observed, the second of which was identified as (cymene)[sub 3]Os[sub 3]S[sub 2]. This species is more stable with respect to loss of cymene than the corresponding (cymene)[sub 3]Ru[sub 3]S[sub 2]. Attempts were made to intercept intermediates in these fragmentation processes by employing PPh[sub 3] as a trapping agent. For the Ru case, PPh[sub 3] completely changed the course of the reaction and no tetramethylfuran was generated. Instead we obtained the structurally unusual [eta][sup 6]-acyl thiolate complex (5). We propose that this unimolecular step involves the formation of ([eta][sup 4]-cymene)Ru([eta][sup 6]-SC[sub 3]Me[sub 3]COMe). The forward rate for this equilibration is far slower than the rate of isomerization of the acyl thiolate and far faster than that for the unassisted thermal decomposition of (cymene)Ru(SC[sub 3]MesCOMe). This result leads to a more global assessment of the reactivity of the acyl thiolates: the orientation of the carbonyl center determines the decomposition pathway. 21 refs., 7 figs., 1 tab.

DOE Contract Number:
FG02-90ER14146
OSTI ID:
6602400
Journal Information:
Organometallics; (United States), Vol. 14:1; ISSN 0276-7333
Country of Publication:
United States
Language:
English