E. A. Koerner Von Gustorf

Reactions of M(CO)6 (M Cr, Mo) with formamidines

Abstract The reactions of hexacarbonyl-molybdenum and -chromium with arylformamidines yield Mo 2 {HC(NR) 2 } 4 and Cr 2 {HC(NR) 2 } 4 , respectively. In the case of Mo the reaction proceeds by the formation of pentacarbonyl formamidinemolybdenum and tetracarbonyldiformamidinemolybdenum complexes. Reaction of Mo 2 {HC(NR) 2 } 4 with Mo(CO) 6 yield the novel complexes Mo 2 {HC(NR) 2 } 3 -{HC(NR)NR · Mo(CO) 3 } and Mo 2 {HC(NR) 2 } 2 {HC(NR)NR · Mo(CO) 3 } 2 , in which the [Mo(CO) 3 ] moiety is bonded to one of the aromatic groups. In the case of chromium, only Cr 2 {HC(NR) 2 } 3 {HC(NR)NR · Cr(CO) 3 ¦ could be prepared. In solution, the formamidine complexes show monomer—dimer equilibria, which are strongly dependent on the nature of R. W(CO) 6 reacts with formamidines, but did not yield complexes analogous to those for chromium and molybdenum. The properties of the new complexes are discussed.

[η-(trans-1,2-dihalogenäthylen)]-tetracarbonyleisen-komplexe: thermische umwandlung in μ-[1-η: 1-2-η(trans-2-halogenvinyl)]-μ-halogen-bis(tricarbonyleisen)-(FeFe)-komplexe und weitere enthalogenierungsreaktionen

trans-1,2-Dihalogenoethylenes react with enneacarbonyldiiron in benzene to give the binuclear complexes μ-[trans-(CHXCH)]-μ-(X′)[Fe(CO)3]2 (III). The initially formed olefin-tetracarbonyliron complexes [trans-(CHXCHX′)]Fe(CO)4 undergo insertion of a second [Fe(CO)4] into a carbon—halogen bond finally leading to III. Some reactions of III occur with elimination of the halogen from the vinyl group to yield products which are also available from reactions of acetylene with carbonyliron complexes.

Chemical synthesis with metal atoms: The reaction of 1,4- and 1,3-cyclohexadiene with chromium atoms and trifluorophosphine

Abstract The reaction of 1,3-cyclohexadiene, chromium atoms, and PF3 yields bis(tetrahapto-cyclohexadiene)bis(trifluorophosphine)chromium (I). The reaction of the 1,4-cyclohexadiene, chromium atoms and PF3 initially yields pentahapto-cyclohexadienylhydridotris(trifluorophosphine)chromium(II), which rearranges to I in the presence of silica gel.

Chemical syntheses with metal atoms

Abstract Metal evaporation syntheses of [Cr(C7H7)(C7H10)], [Cr(C7H8)(PF3)3], metal carbonyls, and anhydrous metal acetylacetonates are described.

Quantum yields in photolysis of (diene)tricarbonyliron and bis(diene)carbonyliron complexes

Abstract Photolysis of diene carbonyliron complexes in the presence of excess trimethylphosphite results in both carbonyl replacement (ΦCO typically 0.01–0.5) and diene replacement (ΦD typically 0.001–0.07). All quantum yields are higher at shorter wavelengths, as is the ratio ΦCO/ΦD. A variety of evidence indicates the photolytic formation of transient (η2-diene)iron intermediates, which are ineffectively trapped by trimethylphosphite due to rapid reversion to the starting (η4-diene)carbonyliron complexes.

Chemical synthesis with metal atoms: the reaction of iron with some conjugated dienes

Abstract Complexes have been obtained by the reaction of iron atoms with butadiene or styrene at - 196°C followed by treatment with ligands such as CO or (MeO) 3 P.

Enthalogenierung von 1,2-dihalogenverbindungen bei der photochemischen umsetzung mit pentacarbonyleisen: synthese von tetracarbonyl-ferracyclopent-3-en-2,5-dionkomplexen

Abstract o -Diiodobenzene and cis -2,3-dibromobut-2-ene are dehalogenated by photoreaction with pentacarbonyliron to give substituted tetracarbonyl-ferracyclopent-3-en-2,5-dione complexes.

Mechanism of the fluxional behaviour in (1–5-η-cycloheptadienyl)-(1–5-η-cycloheptatrienyl)iron

Evidence for a 1,2-shift mechanism of the 1–5-η-cycloheptatrienyl moiety with respect to the central iron atom of the title compound is presented together with absolute assignments of the 13C n.m.r. chemical shifts of the C7H7 ring. A low-temperature rocking motion of both rings can be frozen out at –70 °C.