Syntheses of deuterated sandwich- and piano-stool organo-iron complexes and polyalkylbenzenes

Article abstract of DOI:10.1016/0022-328X(91)80053-M

Deuteration of cationic iron sandwich complexes of the FeCp(arene)⁺ family has been achieved by use of 1 M NaOD in D2O.The deuterated complexes are the starting point for the syntheses of various organo-iron and aromatic compounds.

Full text of DOI:10.1016/0022-328X(91)80053-M

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1H NMR (CD~COCD3, [FeCP2] as internal standard) 2.30 (m, C6CD3, 2H); 1.70 (m,
CsCD3, 3H). "D NMR (CH3COCH3): 2.22 (s, C6(CD3)); 1.71 (s, Cs(CD3)). 13C
NMR (CD3CN): 98.5 (Ca ring); 87.1 (C5 ring); 14.8 (m, C6(CD3), 1J(CD) 20 Hz);
7.9 (m, C5(CD3), 1J(CD) 20 Hz).
N a / H g reduction of (3.1 mmol) of 10a-d33 in DME gave 1.10 g (88~) of
FeI[Cs(CD3)5][C6(CD3)6], 12-d33 as olive-green needles. M.S. calcd, for C22HsD28Fe
381.3689; found: 381.367 (d28 major labelled species: 16%). Total deuterium
incorporation calculated from d22 to d32 species: 85%.
7. Synthesis of deuterated (Fe[Cs(CDs)5](CO)2)2 , 13-d so
The neutral FeI complex prepared as immediately above (1.10 g, 2.73 mmol) was
dissolved in 150 mL of xylene and the solution transferred under argon by canula
into an autoclave. The temperature was raised to 150°C and the CO pressure to 40
bars and the autoclave mechanically shaken for 12 h. The solvent was removed by
rotary evaporation and the residue extracted with hexane. The purple extract was
concentrated and cooled to -80 o C, and the solid rapidly filtered off and dried
under vacuum, yielding 0.965 g (67%) of violet crystals of 13-d30 identified from its
infrared spectrum by comparison with that of an authentic undeutcrated sample.
Chromatography of the filtrate on an alumina column with hexane as eluant gave
0.408 g (92%) of deuterated hexamethylbenzene, 5-d18. IH NMR (CDC13, [FeCp2]
as internal standard): 2.12 (m, CD3, 2H). 13C NMR (CDC13): 132.1 (C6 ring); 16.2
(m, CD3, J(CD) 20 Hz).
8. Synthesis of deuterated Fe[Cs(CDz)5](CO)2Br, 14-dt5
Following the usual procedure, 0.965 g (1.95 mmol) of 13-da0 was treated with
0.07 mL (1.95 mmol) of Br2 at 0°C in CH2C12 to give, after extraction and
crystallization, 0.92 g (75%) of dark red microcrystals of 14-d15, characterized by
comparison of its infrared spectrum with that of an authentic undeuterated sample
[9]. M.S. calcd, for C12H2D1302Fe79Br 339.0421; found: 339.042 (d12 major labeled
species: 23.5%). Total deuterium incorporation calculated for d7-d15 species: 79%.
9. Intermolecular H~ D exchange
In a Schlenk tube an equimolar mixture of [Fe(CsMe~)(C6Me6)]+[PF6] -, 10a and
10a-d33 was stirred under argon with 1 eq. of tBuOK in THF at 20°C for 1 h.
Removal of the solvent, extraction of the dark-red residue with pentane, and
evaporation of the extract gave a dark-red powder ll-dx. A 1H NMR sample of
ll-d x in C6D6 was prepared in the dry-Lab and the tube sealed under N2. NMR
spectra were periodically recorded until equilibrium, as indicated by the integration
ratios, was reached (8 days). IH NMR (C6D6): 3.46 (m, < 1H); 2.05 (m, 1H); 1.76
(m, 3H); 1.44 (m, 3H); 1.27 (m, 8H). Protonation of the dark red C6D6 solution of
ll-d x with CF3CO2H immediately precipitated the yellow acid
[Fe(CsMes)(C6Me6)]-d16+[CF3CO2] -. 1H NMR (CDaCOCD3): 2.29 (m, C6Mes,
9H); 1.68 (m, CsMes, 8H).
10. Synthesis of Fe[Cs(CDz)sI(CeH6)PF6, lS-dlz
In a Schlenk tube under argon 0.41 g (1 mmol) of Fe(CsMes)(C6H6)PF6, 15 [9],
was dissolved in 2 mL of CD3COCDa to give a yellow solution and 5 mL of 1 M
NaOD/D20 solution were added. The biphasic mixture was refluxed for 12 h and