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COMMUNICATIONS
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Commhfnzi.atzbns T O T H E EDITOR Alkyl Derivatives of Manganese Carbonyl Sir:
the first synthesis of acyl metal carbonyl compounds. On treatment of a tetrahydrofuran solution of sodium manganese pentacarbonyl with aceWe to report the first derivatives Of tyl chloride, acetylmanganese pentacarbonyl, m.p. a carbonyl* Previous authors have reported 54-55", mas obtained in 51% yield as a white, volathe synthesis of cyclopentadienyl metal carbonyls' tile, crystalline solid. and alkyl derivatives thereof2 as well as acetylene A ~ calcd, ~ for ~ c ,. H ~ o ~ M ~ C,: 35.32; H, 1.27; and allene codplexes of metal carbonyl^,^^^ but we Mn, 23.1, Found: c, 35,2; H, 1.28; Mn, 23.1. know of no previous report of stable alkyl metal A similar reaction using benzoyl chloride gave carbonyls. benzoylmanganese pentacarbonyl in 80% yield as a Manganese carbonyl dissolved in tetrahydro- .Il;hite,volatile, crystalline solid, m.p. 95-96", furan was smoothly converted to a solution of Anal. Calcd, for ClzH50eMn:c, 48.1;H, 1.68; NaMn(C0)5 when treated with an excess of 1% so- Mn, 18.3. Found: c, 48.2; H, 2.03; M ~18.3. , dium amalgam or finely divided sodium in an inert The propionyl and isobutyryl compounds atmosphere. This solution, maintained in the inert also prepared. atmosphere, was decanted from excess sodium and The infrared spectrum of the acetyl compound treated with dimethyl sulfate or methyl iodide. Re- showed a carbon hydrogen stretching band at 3,48 moval of solvent and recrystallization from petro- and bands at 4.75 p , 4.9 pLIand 5.02 in the metalloleum ether followed by sublimation gave colorless carbonyl region. In addition, a ketonic carbonyl w.as Of manganese PentacarbonY1, m.P* noted a t 6.08 p . The benzoyl compound likewise 94.5-95" (uncorr.). showed bands at 3.28 p, 4.7 p, 4.85 p, 4.9 p, and Anal. Calcd. for C6H3Mn06: c, 34.3; H, 1.43; 6.2 p. Mn>26*2; mol. wt., 210. Found: 34.5; H, l.37; Pyrolysis of acetylmanganese pentacarbonyl Mn, 26*4;mol. wt.7 207 (crYoscoPic in benzene). gave a smooth evolution of carbon monoxide with The crystalline compound is stable and volatilizes the formation of methylmanganese pentacarbonyl. readily in a stream of air. This decarbonylation was reversible with the A corresPonding benzyl derivative may be Pre- methyl derivative being converted to the acetyl Pared using chloride. This materia1, m*P* derivative a t room temperature and 500 p.s,i.g. 37.5-38.5' (uncorr.) is pale yellow and likewise sta- carbon monoxide. ble to air in the solid form. It is somewhat less volaPyrolysis of the benzoyl product also proceeded tile than the methyl compound. with loss of carbon monoxide and formation of And. Calcd. for ClZH7Mn05:C, 50.4; H, 2.45; phenylmanganese pentacarbonyl, m.p. 52", as a white volatile crystalline solid. Mn, 19.3. Found: C, 49.7; H, 2.28; Mn, 19.6. The infrared spectrum of the methyl compound Anal, Calcd. for Cl1H6O6Mn:C, 48.5; H, 1.85; dissolved in carbon disulfide shows bands a t 3.5 p Mn, 20.2. ~ ~C, 48.9; ~ H, 1.95; ~ M d~20.2. , : (carbon-hydrogen stretching); 4.8 p, 5.0 put and 5 . l The infrared spectrum of this compound showed p in the metallocarbonyl region and a band a t 8.5 p . no ketonic carbonyl band in the 6.0-6.2 p region. This work will be more completely discussed in a and acetyl compounds Bromination of the forthcoming publication. gave methyl bromide and acetyl bromide, respecRESEARCH LABORATORIES REX D. CLossoN tively, in addition to bromomanganese pentacarETHYLCORP. JOHN KOZIKOWSKI bony1 T. H. coFFrELD which has been obtained by direct brominaDETROIT,MICH. tion of manganese carbonyl. The reversible carbonReceived April 9, 1957 ylation and the bromination reactions and spectral (1) E. 0. Fischer, Angew. Chem., 67, 475 (1955)' T. S. data cited above support the conclusion that methyl Piper, F A. Cotton, and G . Wilkinson, J. Inorg. Nucl. and acetyl manganese bonds exist in these comChem., 1, 165 (1955). (2) T. S. Piper and G. Wilkinson, J . Inorg. Nucl. Chem., Pounds. A complete discussion of the above work includ3, 104 (1956). (3) H. W. Sternberg, H. Greenfield, R. A. Friedel, J. ing application of the reversible carbonylation to Wotis, R. Markby, and I. %der, J . Am. Chem. S0C.j 76, oxo-reaction mechanism \vi11 be reported in a fu1457 (1954). (4) H. Greenfield, I. Wender, and J. H. Wotiz, J. Org. ture publication. _ _ _ I _
Chem., 21, 875 (1956).
Acyl Manganese Pentacarbonyl Compounds Sir: The synthesis of an alkyl metal carbonyl cornpound has been rep0rted.l We now wish to report
RESEARCH LABORATORIES ETHYL CORP. DETROIT,R~ICH.
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T. H. COFFIELD KOZIKOWSKI REX D. CLOSSON
JOHN
Received April 9, 1957
( I ) R.D. CIosson, J. Kozikowski, and T. H. Coffield, J . Org. Chem., 22, 598 (1957).
