Reactivity patterns of transition metal hydrides and alkyls
The complex PPN/sup +/ CpV(CO)/sub 3/H/sup -/ (Cp=eta/sup 5/-C/sub 5/H/sub 5/ and PPN = (Ph/sub 3/P)/sub 2/) was prepared in 70% yield and its physical properties and chemical reactions investigated. PPN/sup +/ CpV(CO)/sub 3/H/sup -/ reacts with a wide range of organic halides. The organometallic products of these reactions are the vanadium halides PPN/sup +/(CpV(C)/sub 3/X)/sup -/ and in some cases the binuclear bridging hydride PPN/sup +/ (CpV(CO)/sub 3/)/sub 2/H/sup -/. The borohydride salt PPN/sup +/(CpV(CO)/sub 3/BH/sub 4/)/sup -/ has also been prepared. The reaction between CpV(CO)/sub 3/H/sup -/ and organic halides was investigated and compared with halide reductions carried out using tri-n-butyltin hydride. Results demonstrate that in almost all cases, the reduction reaction proceeds via free radical intermediates which are generated in a chain process, and are trapped by hydrogen transfer from CpV(CO)/sub 3/H/sup -/. Sodium amalgam reduction of CpRh(CO)/sub 2/ or a mixture of CpRh(CO)/sub 2/ and CpCo(CO)/sub 2/ affords two new anions, PPN/sup +/ (Cp/sub 2/Rh/sub 3/(CO)/sub 4/)/sup -/ and PPN/sup +/(Cp/sub 2/RhCo(CO)/sub 2/)/sup -/. CpMo(CO)/sub 3/H reacts with CpMo(CO)/sub 3/R (R=CH/sub 3/,C/sub 2/H/sub 5/, CH/sub 2/C/sub 6/H/sub 5/) at 25 to 50/sup 0/C to produce aldehyde RCHO and the dimers (CpMo(CO)/sub 3/)/sub 2/ and (CpMo(CO)/sub 2/)/sub 2/. In general, CpV(CO)/sub 3/H/sup -/ appears to transfer a hydrogen atom to the metal radical anion formed in an electron transfer process, whereas CpMo(CO)/sub 3/H transfers hydride in a 2-electron process to a vacant coordination site. The chemical consequences are that CpV(CO)/sub 3/H/sup -/ generally reacts with metal alkyls to give alkanes via intermediate alkyl hydride species whereas CpMo(CO)/sub 3/H reacts with metal alkyls to produce aldehyde, via an intermediate acyl hydride species.
- Research Organization:
- California Inst. of Tech., Pasadena (USA)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 5183113
- Report Number(s):
- LBL-10214
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400201 -- Chemical & Physicochemical Properties
400301* -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
ALKENES
ALKYLATION
BOROHYDRIDES
BORON COMPOUNDS
CARBONYLS
CHEMICAL PROPERTIES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
COBALT COMPLEXES
COMPLEXES
CYCLOALKENES
CYCLOPENTADIENE
DIENES
HYDRIDES
HYDROCARBONS
HYDROGEN COMPOUNDS
KINETICS
MOLYBDENUM COMPLEXES
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
ORGANOMETALLIC COMPOUNDS
PHOSPHINES
PHOSPHORUS COMPOUNDS
POLYENES
REACTION KINETICS
REDUCTION
RHODIUM COMPLEXES
TRANSITION ELEMENT COMPLEXES
VANADIUM COMPLEXES