Reaction of tetranuclear mixed-metal clusters with carbon monoxide

Journal Article · Mon Sep 01 04:00:00 EDT 1980 · Inorg. Chem.; (United States)

DOI:https://doi.org/10.1021/ic50211a018· OSTI ID:5051625

Fox, J R; Gladfelter, W L; Geoffroy, G L

Reaction of the mixed-metal tetranuclear clusters H/sub 2/FeRu/sub 3/(CO)/sub 13/, H/sub 2/FeRu/sub 2/Os(CO)/sub 13/, H/sub 2/FeRuOs/sub 2/(CO)/sub 13/, HCoRu/sub 3/(CO)/sub 13/, H/sub 2/FeRu/sub 3/(CO)/sub 12/L (L = PMe/sub 2/Ph, PPh/sub 3/), (HFeRu/sub 3/(CO)/sub 13/)/sup -/, and (CoRu/sub 3/(CO)/sub 13/)/sup -/ with CO under relatively mild conditions (P(CO) = 1 atm, t = 0-80/sup 0/C) results in their fragmentation to give trimeric and monomeric products. The fragmentation reactions are generally quite selective: H/sub 2/FeRu/sub 2/Os(CO)/sub 13/, for example, reacts with CO to give Ru/sub 2/Os(CO)/sub 12/, Fe(CO)/sub 5/, and H/sub 2/ with no RuOs/sub 2/(CO)/sub 12/, FeRu/sub 2/(CO)/sub 12/, or FeRuOs(CO)/sub 12/ detected in the product mixture. This reaction and the corresponding fragmentation of H/sub 2/FeRuOs/sub 2/(CO)/sub 13/ provide a convenient means of separating and isolating the mixed-metal trimers Ru/sub 2/Os(CO)/sub 12/ and RuOs/sub 2/(CO)/sub 12/. The reactivity of a particular cluster toward CO is greatly dependent on its metal composition and/or its structure. For example, H/sub 2/FeRu/sub 2/Os(CO)/sub 13/ reacts slowly over a period of several days while the breakdown of HCoRu/sub 3/(CO)/sub 13/ is complete within 1h. The tetrahydride clusters H/sub 4/FeRu/sub 3/(CO)/sub 12/ and H/sub 4/Ru/sub 4/(CO)/sub 12/ first react with CO to displace H/sub 2/ and form the corresponding dihydride clusters which subsequently fragment under the reaction conditions. Kinetic measurements indicate that the fragmentation of H/sub 2/FeRu/sub 3/(CO)/sub 13/ to produceRu/sub 3/(CO)/sub 12/, Fe(CO)/sub 5/, and H/sub 2/ proceeds largely by a second-order, (CO)-dependent path with activation parameters ..delta..H/sup 0/ not equal to = 20.0 +- 2.0 kcal/mol and ..delta..S/sup 0/ not equal to = -25.4 +- 5.8 cal/(mol K). Likewise, fragmentation of H/sub 2/Ru/sub 4/(CO)/sub 13/ to form Ru/sub 3/(CO)/sub 12/, Ru(CO)/sub 5/, and H/sub 2/ proceeds via a second-order, (CO)-dependent path with ..delta..H/sup 0/ not equal to = 12.5 +- 0.5 kcal/mol and ..delta..S/sup 0/ not equal to = -36.6 +- 1.6 cal/(mol K).

• Research Organization: Pennsylvania State Univ., University Park
• OSTI ID: 5051625
• Journal Information: Inorg. Chem.; (United States), Journal Name: Inorg. Chem.; (United States) Vol. 19:9; ISSN INOCA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
AROMATICS
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COBALT COMPOUNDS
COMPLEXES
IRON COMPOUNDS
KINETICS
MEDIUM PRESSURE
MEDIUM TEMPERATURE
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHOSPHORUS COMPOUNDS
REACTION KINETICS
RUTHENIUM COMPLEXES
TRANSITION ELEMENT COMPLEXES
TRANSITION ELEMENT COMPOUNDS