János Takács

Synthesis and some reactions of Fe(CO)2(dppe)(SR)2 and Fe3(CO)6(SAr)6 complexes. The crystal structure of cis, cis,cis-Fe(CO)2(dppe)(SPh)2

Abstract The complexes Fe(CO) 2 (dppe)(SR) 2 (dppe)  Ph 2 PCH 2 CH 2 PPh 2 ; R  s-Bu, Ph, p -C 6 H 4 Me, p -C 6 H 4 OMe, p -C 6 H 4 NHC(O)Me) have been synthesized from Fe 2+ salts by treatment with CO in the presence of dppe and RS − and the crystal structure of the Fe(CO)(dppe)(SPh) 2 derivative has been determined. The ligands occupy cis,cis,cis positions and there are two enantiomeric molecules in the asymmetric unit (space group P 1 − ) of the crystal. The Fe(CO) 2 (dppe)(SR) 2 complexes from 1 2 adducts with HgCl 2 . In the abscence of dppe, methanol solutions of Fe 2+ and ArS − ( 1 2 ; Ar  Ph, p -C 6 H 4 Me, p -C 6 H 4 Me, p -C 6 H 4 OMe) take up CO to give the trinuclear thiolato complexes Fe 3 (CO) 6 (SAr) 6 .

Synthesis and some reactions of HFe3(CO)9(SR) clusters containing primary alkyl groups

Fe3(CO)12 and sodium thiolates reactin THF to form the trinuclear anions Fe3(CO)9(SR)−. The corresponding hydrides HFE3(CO)9(SR) can be obtained by acidification and this enables the preparation of complexes containing primary alkyl groups. When R  Ph only the anion is stable at room temperature. When heated in polar solvents all the complexes readily loose the R group to give HFe3(CO)9S− or Fe3(CO)9S2− and hydrocarbons or carbohydrated organic products.

Synthesis and molecular structure of carbonyl derivatives of iron(II) thiolates containing nitrogen-donor ligands

Abstract Several carbonyl derivatives of iron(II) thiolates containing N-donor ligands with the general formula FeS2N2(CO)2 were prepared in methanol solution starting from FeSO4·7H2O, the appropriate thiol (S) and nitrogen-donor ligand (N), carbon monoxide and a base. The structures of two representatives Fe(SC6H4- NH2-o)2(CO)2 (1) and Fe(SPh)2(H2NC2H4NH2)- (CO)2 (2) were determined. Complex 1 crystallizes with one molecule of THF in the triclinic space group P1, a=5.659(3), b=8.960(6), c=10.624(6) A, α= 105.15(5), β=103.23(5), γ=94.35(5)°, V=500.86 A3, Z=1, Dcalc=1.43 g cm−3. Complex 2 crystallizes in the monoclinic space group P21/c, a=11.739(2), b=9.725(2), c=15.868(2) A, β=101.583(8)°, V= 1774.6 A3, Z=4, Dcalc=1.44 g cm−3. Final agreement factors, R=0.0300, Rw=0.0304 (1787 reflections) for 1; R=0.0368, Rw=0.0369 (2147 reflections) for 2; the absolute configuration of 1 was determined. The octahedral complexes contain the two CO ligands in cis position and the coordinated N atoms are trans to the CO groups. A necessary condition for the stability of such complexes is the presence of at least one chelating ligand; all complexes lose CO on heating and this reaction is (in part) reversible.

Iron(II) carbonyl complexes containing xanthate, dithiocarbamate or dithiophosphate ligands

SummaryStarting from Fe(CO)4I2, octahedral FeII carbonyl derivatives of the types Fe(CO)2(xan)2, Fe(CO)3(xan)I and Fe(CO)3(dtc)I were prepared (xan = xanthate, dtc = dithiocarbamate). Infrared evidence was obtained for the formation of Fe(CO)2(dtp)2 complexes (dtp = dithiophosphate). The dixanthate complexes are also formed from FeII salts and potassium xanthates by CO absorption in MeOH/H2O solution.

Iron(II) thiolates as reversible carbon monoxide carriers

Abstract Solutions of several iron(II) thiolato complexes in methanol, dimethylformamide or 2-ethoxyethanol reversibly absorb and release carbon monoxide at atmospheric pressure and 20–50 °C. Solutions of Fe(SPh) 2 (H 2 NCH 2 CH 2 NH 2 ) (CO) 2 and of an anionic complex tentatively formulated as [Fe 2 (SPh) 5 (CO) 4 ] − in 2-ethoxyethanol and of Fe(L-SCH 2 CH(NH 2 )COOEt) 2 (CO) 2 in dimethylformamide were found to be most effective for the separation of CONe 2 gas mixtures.

Synthesis and X-ray crystal structure of Fe(CO)2[O2CCH2P(C6H5)2]2, the first iron carbonyl complex with two carboxylate ligands

Abstract Fe(CO)2[O2CCH2P(C6H5)2]2 (I) was synthesized from FeSO4·7H2O and Na[O2CCH2P(C6H5)2] under CO pressure. The 18-electron compound has an octahedral coordination sphere around Fe2+. Two diphenylphosphinoacetate ligands are bonded to the iron through the phosphorus atoms and one of the oxygen atoms of the carboxylato groups. Two carbonyl groups and two carboxylato oxygen atoms are in cis positions to each other, while the phosphorus atoms adopt trans positions. The unit cell contains both enantiomers of the chiral octahedral compound.

Synthesis of new mixed-alkyl rhenium(VII) organoimido complexes and a new facile route to Me3SiORe(NBut)3

Abstract Alkylation of the rhenium(VII) dichloro compound of the formula MeRe(NR′) 2 Cl 2 Py ( 1 ) with MeMgCl, Et 2 Zn and Pr i MgCl yields the d 0 trialkyl diimido complexes of the formula MeR 2 Re(NR′) 2 ( 2a–c ) (R = Me, Et, Pr i ; R′ = 2,6-dimethylphenyl). Compound 2a is stable at 25°C, while compounds 2b and c decompose within a few hours. In a similar manner the alkylation of the new tert-butyl imido derivative MeRe (NBu t ) 2 Cl 2 ( 4 ) [prepared from MeRe(NBu t ) 3 ( 3 ) by hydrochlorination] yields the trialkyl complexes of the formula MeR 2 Re(NBu t ) 2 ( 5a–c ) (R = Me, Et and Pr i ), of which the mixed-alkyl species are again thermolabile. Analysis of the gas-phase decomposition products revealed a rather complex decomposition pathway, in which the β-hydrogen elimination is likely to play a minor role. Reaction of the polymeric oxo species of the formula Me 3 SnOReO 3 ( 6 ) with the silylamine Bu t NHSiMe 3 gives, surprisingly cleanly, the monomeric tris-imido compound of the formula Me 3 SiORe(NBu t ) 3 ( 7 in 93% yield.