Inorganic Chemistry
Article
removed under vacuum, and the crude vinylidene-iron product was
washed several times with ether and analyzed by IR and 31P NMR,
and, for the new products, by elemental analyses and mass
spectrometry.
Cp*Fc), 3.75 (s, 2Hβ, Cp*Fc), 4.24 (s, 5H, Cp unsub), 7.24−8.0 (m,
20H, Ph, CH of dppe). 13C NMR (75.0 MHz, CDCl3), δppm: 10.54
(CH3, Cp*), 28.33 (CH2), 69.77 (CH of Cp*Fc), 71.93 (CH of
Cp*Fc), 78.76 (Cp unsub), 79.84 (Cq, Cp*), 127.28, 127.77 (Ph p),
128.51, 128.88 (Ph m), 131.75, 133.95 (Ph o), 138.74 (Ph ipso),
142.78 (Ph ipso). 31P NMR (121 MHz, CDCl3), δppm: 106.27 (Fe-
dppe). IR (KBr): 2068 cm−1 (νCC). MALDI-TOF: calc. m/z for M+
(C48H48P2Fe2) 798.55; found 798.18. CV (CH2Cl2; supporting
electrolyte [(n-Bu)4N][PF6] 0.1 M; 293 K): two reversible waves,
E1/2 = 0.00 and 0.48 V vs. FeCp2*. Anal. Calcd for C48H48Fe2P2: C,
72.20, H, 6.06; found: C, 72.27, H, 6.18.
General Procedure for the Synthesis of the Iron-Alkynyl
Complexes. The crude iron-vinylidene complex synthesized as
indicated above was dissolved in dry THF, and a stoichiometric
amount of t-BuOK was added. The reaction mixture was stirred at
room temperature (r.t.) for 2 h. The solvent was removed under
vacuum, and the alkynyl-iron complex was extracted with ether or
DCM, and filtered through Celite to remove the KPF6 formed. The
solvent was removed under vacuum. The orange-red powder obtained
Synthesis of the Trimetallic Complexes 10 and 13. The
complex 13 was synthesized from (i) 1 (179 mg, 0.5 mmol), dppe
(199.6 mg, 0.5 mmol) and ethynylbiferrocene (197 mg, 0.5 mmol),
which led to 10; (ii) t-BuOK (112.2 mg, 2 equiv 1 mmol) and 10
following the general procedure for the synthesis of the iron−alkynyl
complexes 13. An orange powder was obtained, and 13 (0.365 mg,
80% yield) was separated by extraction with ether.
1
was analyzed by H, 13C, and 31P NMR, and IR, elemental analysis,
and MALDI-TOF mass spectrometry.
Synthesis of CpFe(dppe)CC-Fc, 11. The iron-alkynyl com-
plex 11 was synthesized from the following: (i) 1 (0.250 g, 0.699 mmol),
dppe (0.279 g, 0.699 mmol), and ethynylferrocene (0.147 g, 0.699 mmol)
producing the vinylidene complex 8; (ii) t-BuOK (0.091 g, 0.699 mmol)
and 8 following the general procedure for the synthesis of the iron-alkynyl
complexes. The complex 11 dissolved in DCM, filtered through Celite,
and after removing the solvent under vacuum, it was obtained as a red-
orange powder in 99% yield.
1
Complex 10: H NMR (400 MHz, (CD3COCD3), δppm: 3.12 (m,
4H, CH2 of dppe), 3.76 (t, 2H/C5H4), 3.98 (s, 5H, Cp unsub), 4.08(t,
4H/C5H4), 4.27(t, 2H/C5H4), 4.44(t, 4H/C5H4), 5.05 (s, CH), 5.39
(s, 5H, Fc unsub), 7.32−7.60 (m, 20H, Ph of dppe), 2.07(m,
(CD3COCD3), 3.12(s, H2O). 13C NMR (100 MHz, (CD3COCD3),
δppm: 27.95 (CH2 of dppe), 66.55−68.82 (CH/C5H4), 69.29 (Cp
unsub), 79.94 (Ci/C5H4), 89.40 (Fc unsub), 123.11 (CFc),
129.29−132.69 (Ph of dppe), 364.48 (t, FeC), 29.30 and 205.77
(CD3COCD3). 31P NMR (121 MHz, CD3COCD3), δppm: 94.29 (Fe-
1
Complex 8: H NMR (600 MHz, (CD3)2CO), δppm: 3.16 (m, 4H,
CH2 of dppe), 3.38 (t, 2H/C5H4), 4.02(s, 5H, Fc unsub), 4.47(t, 2H/
C5H4), 5.16 (s, CH), 5.48 (s, 5H, Fc unsub), 7.18−7.70 (m, 20H, Ph
of dppe), 1.12(m, CH3 of ether), 3.41(m, CH2 of ether), 2.06(m,
(CD3)2CO), 2.96(s, H2O). 13C NMR (150 MHz, (CD3)2CO),
δppm:.27.84 (CH2 of dppe), 66.30 (CH/C5H4), 67.83 (CH/C5H4),
69.13 (Fc unsub), 79.74 (Ci/C5H4), 89.29 (Fc unsub), 123.23 (
CFc), 129.08−132.58 (Ph of dppe), 365.90 (t, FeC), 14.78 (CH3 of
pentane), 29.06 and 206.45 (CD3)2CO). HMBC (600 MHz,
(CD3)2CO): see Supporting Information, page S19; 31P NMR (121
MHz, CD3COCD3), δppm: 93.49(Fe-dppe), −144.23 (m, PF6-); IR
(KBr): 1963 cm−1 (νCC), 839 cm−1; (νPF6) MALDI-TOF: calc. m/z
for M+ (C43H39 Fe2P2) 729.1, found 728.1. CV (electrolyte: [n-
Bu4N][PF6] 0.1M; working and counter electrodes: Pt; reference
−
dppe), −142.90 (m, PF6 ). IR (KBr): 1963 cm−1 (νCC), 839 cm−1
(νPF6). MALDI-TOF: calc. m/z for M+ (C43H39Fe2P2) 913.4228,
found 912.1177.
Complex 13: 1H NMR (300 MHz, C6D6), δppm: 2.08 (m, 2H, CH2),
2.67 (m, 2H, CH2), 3.79 (t, 2H, BiFc), 3.81 (t, 2H, BiFc), 4.05 (s, 5H,
Fc unsub), 4.06 (t, 2H, BiFc), 4.14 (t, 2H, BiFc), 4.15 (t, 2H, BiFc),
4.28 (s, 5H, Cp unsub), 4.38 (t, 2H, BiFc), 6.98−8.05 (m, 20H, Ph)
13C NMR (200 MHz, C6D6), δppm: 29.86 (CH2), 66.93−70.89 (CH of
BiFc), 79.18 (Cp unsub), 129.06−134.19 (Ph). 31P NMR (121 MHz,
CDCl3), δppm: 118.16 (Fe-dppe). IR (KBr): 2068 cm−1 (νCC).
MALDI-TOF: calc. m/z for M+ (C53H46Fe3P2) 912; found 912.118.
CV (CH2Cl2; supporting electrolyte [(n-Bu)4N][PF6]; 293 K): three
reversible waves, E1/2 = 0.00 V, 0.049 V and 0.085 V (ΔE = 0.1 V) vs.
FeCp2*. Anal. Calc. for C53H46Fe3P2.CH2Cl2: C 65.03, H 4.85; found
65.28, H 4.93.
electrode: Ag; internal reference: FeCp*2; solvent CH2Cl2): E1/2
=
0.510 and 0.690 V vs. FeCp*2.
1
Complex 11: H NMR (CDCl3, 300 MHz): 7.74−7.20 (m, 20H,
arom. CH of dppe), 4.21 (s, 5H, Cp), 3.77−3.65 (m, 9H, Cp of Fc),
2.75 and 2.38 (m, 4H, CH2CH2 of dppe). 13C NMR (CDCl3, 75.0
MHz): 142.4−127.4 (arom.), 79.0 (Cp), 73.4−65.8 (Cp of Fc), 25.6
(CH2 of dppe). 31P NMR (CDCl3, 121 MHz): 106.4 (Fe-dppe).
Infrared (KBr) υCC: 2 066 cm−1. CV: (CH2Cl2; supporting
electrolyte [(n-Bu)4N][PF6] 0.1 M; 293K): two reversible waves at
E1/2 = 0.00 V (iron-alkynyl) and 0.650 V (ferrocenyl) vs. FeCp2*. MS
(ESI m/z), calcd. for C43H38P2Fe2: 729.1, found: M+ 728.1. Anal. Calc.
for C43H38P2Fe2: C 70.90, H 5.26; found: C 70.56, H 5.21.
Syntheses of the Fulvalene Tetrairon Complexes 14 and
15. The complex 15 was synthesized from (i) [Fe2(η10,μ2-fulvalene)-
(η6-C6H5CH3)2] [PF6]2,29 t-BuOK and allylbromide were stirred in
THF at r.t. for 1 h, then the solvent was removed under vacuum, the
residue was extracted with DCM and filtered. The solvent was
removed under vacuum, and 1H NMR in CD3CN indicated
monoallylation (butenyl chain). The complex (78 mg, 0.095 mmol),
dppe (76 mg, 2 equiv., 0.19 mmol) and ethynylferrocene (40 mg, 2
equiv. 0.19 mmol) were introduced into a Schlenk flask, and visible-
light photolysis was carried according to the general procedure for the
synthesis of vinylidene complexes, which produced 14; (ii) reaction
between 14 and t-BuOK (21 mg, 2 equiv., 0.19 mmol) following the
general procedure for the synthesis of the iron-alkynyl complexes
produced 15 as a brown powder that was separated by extraction with
ether (0.137 mg, 99% yield).
Synthesis of CpFe(dppe)CC−Fc*, 12. The complex 12 was
synthesized from (i) 1 (319 mg, 0.89 mmol), dppe (355 mg, 0.89
mmol), and 1,2,3,4,5-pentamethyl,1′-ethynylferrocene (250 mg, 0.89
mmol) producing 9; (ii) t-BuOK and 9 (100 mg, 0.89 mmol)
following the general procedure for the synthesis of the iron-alkynyl
complexes. A yellow powder was obtained, and the complex 12 (0.703
g, 99% yield) was separated by dissolving in ether, filtering through
Celite, and evaporating the solvent.
Vinylidene complex 9: 1H NMR (400 MHz, (CD3)2CO), δppm: 1.54
(s, 15H, CH3 of Cp), 3.07−3.19 (m, 4H, CH2 of dppe), 4.26 (t, 1H/
C5H4), 4.48 (t, 1H/C5H4), 4.74 (t, 2H/C5H4), 5.40(s, 5H, Fc unsub),
5.74(s, CH), 7.38−7.67 (m, 20H, Ph of dppe), 2.06 (m, (CD3)2CO)).
13C NMR (400 MHz, (CD3)2CO)), δppm: 10.41 (CH3/Cp*), 27.90
(CH2/dppe), 69.74 (CH/C5H4), 79.91 (CH/C5H4), 80.20 (CH/
C5H4), 81.02 (CH/C5H4), 88.67 (CH/C5H4), 89.15 (Fc unsub),
116.54 (CFc), 129.09−132.72 (Ph of dppe), 364.08 (t, FeC),
29.14 and 205.46 (CD3)2CO). 31P NMR (121 MHz, CD3COCD3),
Complex 14: 1H NMR (400 MHz, (CD3)2CO), δppm): 3.21(m, 8H,
CH2 of dppe), 3.23−4.22 (t, 16H/C5H4), 3.99 (s, 10H, Fc unsub),
5.26(s, 2H, CH), 7.28−7.58(m, 40H, Ph of dppe), 2.06 (m,
(CD3)2CO). 13C NMR (100 MHz, (CD3)2CO), δppm: 26.94(CH2/
dppe), 67.44(CH/C5H4), 68.32 (CH/C5H4), 68.97 (CH/C5H4),
69.15 (Cp unsub), 86.36 (CH/C5H4), 88.19 (CH/C5H4), 88.55
(CH/C5H4), 122.75 (CFc), 129.39−132.89 (Ph of dppe), 364.85
(t, FeC), 29.14 and 205.46 ((CD3)2CO). 31P NMR (121 MHz,
−
δppm: 93.70 (Fe-dppe), −144.21 (m, PF6 ). IR (KBr): 1957 cm−1
−
(νCC), 836 cm−1 (νPF6). MS (ESI m/z), calcd. for C48H49P2Fe2:
CD3COCD3, δppm): 92.93 (Fe-dppe), −131.27 (m, PF6 ). IR (KBr):
1966 cm−1 (νCC), 839 cm−1 (νPF6). MS (ESI m/z), calcd. for
C86H76P4Fe4: 1456.7987, found: M+ 1454.2416. Anal. Calcd for
C86H76F12Fe4P6.H2O: C 58.53, H 4.45; found: C 58.27, H 4.75.
799.54, found: M+ 798.19.
1
Alkynyl complex 12: H NMR (300 MHz, CDCl3), δppm: 1.60 (s,
15H, Cp*), 2.07 (m, 2H, CH2), 2.56 (m, 2H, CH2), 3.37 (s, 2Hα,
125
dx.doi.org/10.1021/ic201206e | Inorg. Chem. 2012, 51, 119−127