
Supporting information
![]() | Crystallographic Information File (CIF) https://doi.org/10.1107/S160053680702764X/lh2417sup1.cif |
![]() | Structure factor file (CIF format) https://doi.org/10.1107/S160053680702764X/lh2417Isup2.hkl |
CCDC reference: 654738
p-Nitrophenylferrocene was prepared by the method of Hu et al. (2001a). The crude product was purified using activated silica as the stationary phase and 95:5 hexanes:ethyl acetate as the eluent (yield 48%). 1H NMR (400 MHz, CDCl3): 4.067 (s, 5H, C5H5), 4.487 (pt, 2H, C5H4), 4.751 (pt, 2H, C5H4), 7.710 (d, 2H, C6H4), 8.150 (d, 2H, C6H4). MS: calculated for (M+) 307 m/z, found 307 m/z. p-Nitrophenylferrocene was also analyzed by single-crystal diffraction (Zeller et al., 2004) confirming the previously reported structure (Roberts et al., 1988, Gallagher et al., 1997). p-Ferrocenylaniline was prepared via the method of Hu et al. (2001b) from p-nitrophenylferrocene. The product was purified via column chromatography using activated silica as the stationary phase and 70:30 hexanes:ethyl acetate as the eluent (yield 88%). 1H NMR: 3.620 (s, 2H, NH2), 4.045 (s, 5H, C5H5), 4.249 (pt, 2H, C5H4), 4.552 (pt, 2H, C5H4), 6.651 (d, 2H, C6H4), 7.303 (d, 2H, C6H4). MS: calculated for (M+) 277 m/z, found 277 m/z.
X-ray quality single crystals of p-ferrocenylaniline were prepared via kinetically controlled solvent evaporation from 70:30 hexanes:ethyl acetate solutions to give yellow platelets.
Cp and aromatic H atoms were placed in calculated positions [C—H = 0.95 Å] and were refined with Uiso(H) = 1.2 Ueq(C) of the adjacent carbon atom. Amine hydrogen atom positions and isotropic displacement parameters were freely refined.
The s.u. values of the cell parameters are taken from the software recognizing that the values are unreasonably small (Herbstein, 2000).
Ferrocene-containing dimers have received considerable interest over the years due to their potential applications in electrocatalysis (Togni & Hayashi, 1995; Sawamura & Ito, 1992; Nicolosi et al., 1994), ferromagnetism (Miller et al., 1996), chemical and biochemical sensing (Navarro et al., 2005; Brown et al., 2005; Okochi et al., 2005; Hickman et al., 1991) and self-assembled monolayer chemistry (Chidsey et al., 1990; Creager & Rowe, 1997). They are also of growing interest due to their unique structural, electrochemical and electronic structural properties. The production of dimeric ferrocenylamides has been hampered by the tedious synthesis of aminoferrocene, as it is difficult to produce in high enough yields to be useful in multi-step syntheses. In addition, the production of 1,1'-diaminoferrocene as the major product of most reaction pathways is a serious drawback. Although this compound can be purchased commercially, it is extremely expensive. Its phenyl derivative, the title compound p-ferrocenylaniline (I), on the other hand, can be easily produced in a two step synthesis from ferrocene by reaction with diazotated p-nitroaniline (Hu et al., 2001a), followed by the reduction of the resulting p-nitrophenylferrocene with Sn/HCl to produce the title compound p-ferrocenylaniline (Hu et al., 2001b). This paper presents the single-crystal structure of the title compound.
p-Ferrocenylaniline crystallizes in the orthorhombic space group Pbca with 8 molecules per unit cell (Figure 1). The conformation of the two Cp rings towards each other is close to eclipsed, and the substituted Cp and the phenyl ring are basically coplanar with a dihedral angle between the planes defined by C6 to C10 and C11 to C16 of 8.7 (2)°, a value not too different to that found for p-nitrophenylferrocene (13.5 (2)°, Zeller et al., 2004; see also: Roberts et al., 1988, Gallagher et al., 1997).
The hybridization of the amino group shows a tendency towards sp3 hybridization with angles between 114 and 117° (Table 1). The nitrogen atom is located slightly above the plane of the phenyl ring by 0.074 (3) Å. Together with the orientation of the amino hydrogen atoms, which are located below the phenyl plane by 0.11 (4) and 0.23 (4) Å, this allows for a conjugation of the nitrogen lone pair with the π electrons of the aromatic ring. This is in agreement with the 1H NMR spectral values, which are typical for ferrocenyl compounds with electron donating substituents: The cyclopentadienyl and phenyl protons have been shifted upfield from TMS, thus further conforming extensive π-overlap and electronic communication along the unsaturated backbone.
In contrast to aminoferrocene (Perrine et al., 2005) and also 1,1'-diaminoferrocene (Shafir et al., 2000), but similar to other structurally analyzed ferrocenyl amines (Rogers et al. 1998, Sunkel et al., 2000, Takaki et al., 1959) the title compound does not form hydrogen bonds in the solid state. Also no π-π stacking interactions are found in the structure: neighboring molecules are roughly perpendicular to each other with the C—H groups pointing towards the π-electrons of neighboring Cp and aromatic units (but at distances larger than the sum of the van-der-Waals radii). The packing and the lattice energy thus seems to be soley based on weak disperion interactions.
For the synthesis of p-ferrocenylaniline, see: Hu et al. (2001a,b). For related structures, see: Perrine et al. (2005); Shafir et al. (2000); Rogers et al. (1988); Sunkel et al. (2000); Takaki et al. (1959); Roberts et al. (1988); Gallagher et al. (1997); Zeller et al. (2004). For applications of ferrocene-containing dimers in electrocatalysis, see: Togni & Hayashi (1995); Sawamura & Ito (1992); Nicolosi et al. (1994); in ferromagnetism, see: Miller et al. (1988); in chemical and biochemical sensing, see: Navarro et al. (2005); Brown et al. (2005); Okochi et al. (2005); Hickman et al. (1991); and in self-assembled monolayer chemistry, see: Chidsey et al. (1990); Creager & Rowe (1997).
For related literature, see: Herbstein (2000); Rogers et al. (1988).
Data collection: SMART (Bruker, 2002); cell refinement: SAINT-Plus (Bruker, 2003); data reduction: SAINT-Plus; program(s) used to solve structure: SHELXTL (Bruker, 2000); program(s) used to refine structure: SHELXTL; molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.
[Fe(C5H5)(C11H10N)] | F(000) = 1152 |
Mr = 277.14 | Dx = 1.504 Mg m−3 |
Orthorhombic, Pbca | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ac 2ab | Cell parameters from 8682 reflections |
a = 9.6762 (7) Å | θ = 2.5–30.5° |
b = 8.0284 (6) Å | µ = 1.21 mm−1 |
c = 31.515 (2) Å | T = 100 K |
V = 2448.2 (3) Å3 | Plate, yellow |
Z = 8 | 0.41 × 0.19 × 0.03 mm |
Bruker SMART APEX CCD area-detector diffractometer | 2821 independent reflections |
Radiation source: fine-focus sealed tube | 2679 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.030 |
φ and ω scans | θmax = 27.5°, θmin = 1.3° |
Absorption correction: multi-scan (SADABS in SAINT-Plus; Bruker, 2003) | h = −12→12 |
Tmin = 0.712, Tmax = 0.960 | k = −10→10 |
22095 measured reflections | l = −40→40 |
Refinement on F2 | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.044 | Hydrogen site location: difference Fourier map |
wR(F2) = 0.095 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.31 | w = 1/[σ2(Fo2) + (0.0245P)2 + 5.1787P] where P = (Fo2 + 2Fc2)/3 |
2821 reflections | (Δ/σ)max = 0.001 |
171 parameters | Δρmax = 0.57 e Å−3 |
0 restraints | Δρmin = −0.34 e Å−3 |
[Fe(C5H5)(C11H10N)] | V = 2448.2 (3) Å3 |
Mr = 277.14 | Z = 8 |
Orthorhombic, Pbca | Mo Kα radiation |
a = 9.6762 (7) Å | µ = 1.21 mm−1 |
b = 8.0284 (6) Å | T = 100 K |
c = 31.515 (2) Å | 0.41 × 0.19 × 0.03 mm |
Bruker SMART APEX CCD area-detector diffractometer | 2821 independent reflections |
Absorption correction: multi-scan (SADABS in SAINT-Plus; Bruker, 2003) | 2679 reflections with I > 2σ(I) |
Tmin = 0.712, Tmax = 0.960 | Rint = 0.030 |
22095 measured reflections |
R[F2 > 2σ(F2)] = 0.044 | 0 restraints |
wR(F2) = 0.095 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.31 | Δρmax = 0.57 e Å−3 |
2821 reflections | Δρmin = −0.34 e Å−3 |
171 parameters |
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. |
Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger. |
x | y | z | Uiso*/Ueq | ||
C1 | 0.5396 (3) | −0.0175 (3) | 0.61108 (8) | 0.0200 (5) | |
H1 | 0.4875 | −0.0652 | 0.6336 | 0.024* | |
C2 | 0.6406 (3) | 0.1104 (3) | 0.61509 (8) | 0.0193 (5) | |
H2 | 0.6677 | 0.1632 | 0.6408 | 0.023* | |
C3 | 0.6937 (2) | 0.1451 (3) | 0.57415 (8) | 0.0191 (5) | |
H3 | 0.7629 | 0.2250 | 0.5676 | 0.023* | |
C4 | 0.6253 (2) | 0.0393 (3) | 0.54461 (8) | 0.0180 (5) | |
H4 | 0.6404 | 0.0364 | 0.5148 | 0.022* | |
C5 | 0.5305 (2) | −0.0611 (3) | 0.56757 (8) | 0.0185 (5) | |
H5 | 0.4711 | −0.1432 | 0.5558 | 0.022* | |
C6 | 0.4561 (2) | 0.4356 (3) | 0.57041 (7) | 0.0155 (5) | |
H6 | 0.5264 | 0.5181 | 0.5709 | 0.019* | |
C7 | 0.4063 (2) | 0.3527 (3) | 0.53379 (8) | 0.0164 (5) | |
H7 | 0.4371 | 0.3705 | 0.5055 | 0.020* | |
C8 | 0.3022 (2) | 0.2383 (3) | 0.54663 (7) | 0.0159 (5) | |
H8 | 0.2514 | 0.1662 | 0.5285 | 0.019* | |
C9 | 0.2876 (2) | 0.2508 (3) | 0.59135 (8) | 0.0150 (4) | |
H9 | 0.2253 | 0.1880 | 0.6083 | 0.018* | |
C10 | 0.3826 (2) | 0.3742 (3) | 0.60670 (8) | 0.0140 (4) | |
C11 | 0.3971 (2) | 0.4271 (3) | 0.65136 (7) | 0.0148 (5) | |
C12 | 0.3038 (3) | 0.3733 (3) | 0.68236 (8) | 0.0176 (5) | |
H12 | 0.2324 | 0.2979 | 0.6747 | 0.021* | |
C13 | 0.3132 (3) | 0.4273 (3) | 0.72402 (8) | 0.0207 (5) | |
H13 | 0.2485 | 0.3888 | 0.7444 | 0.025* | |
C14 | 0.4174 (3) | 0.5385 (3) | 0.73622 (8) | 0.0221 (5) | |
C15 | 0.5119 (3) | 0.5911 (3) | 0.70560 (8) | 0.0223 (5) | |
H15 | 0.5842 | 0.6652 | 0.7134 | 0.027* | |
C16 | 0.5018 (3) | 0.5370 (3) | 0.66416 (8) | 0.0194 (5) | |
H16 | 0.5672 | 0.5749 | 0.6439 | 0.023* | |
Fe1 | 0.48564 (3) | 0.18548 (4) | 0.575918 (10) | 0.01213 (11) | |
N1 | 0.4219 (3) | 0.5988 (4) | 0.77774 (8) | 0.0317 (6) | |
H1A | 0.495 (4) | 0.645 (5) | 0.7857 (12) | 0.034 (10)* | |
H1B | 0.384 (4) | 0.535 (5) | 0.7961 (12) | 0.041 (11)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0177 (11) | 0.0187 (12) | 0.0237 (13) | 0.0051 (10) | 0.0035 (10) | 0.0087 (10) |
C2 | 0.0168 (11) | 0.0213 (12) | 0.0197 (12) | 0.0043 (10) | −0.0037 (9) | −0.0002 (10) |
C3 | 0.0095 (10) | 0.0178 (11) | 0.0301 (14) | 0.0018 (9) | 0.0012 (9) | 0.0032 (10) |
C4 | 0.0154 (11) | 0.0195 (12) | 0.0190 (12) | 0.0069 (9) | 0.0033 (9) | −0.0001 (10) |
C5 | 0.0152 (11) | 0.0114 (10) | 0.0288 (13) | 0.0033 (9) | −0.0011 (9) | −0.0019 (10) |
C6 | 0.0150 (11) | 0.0119 (10) | 0.0198 (12) | 0.0004 (9) | −0.0023 (9) | 0.0018 (9) |
C7 | 0.0183 (11) | 0.0164 (11) | 0.0144 (11) | 0.0056 (9) | −0.0002 (9) | 0.0021 (9) |
C8 | 0.0142 (10) | 0.0165 (11) | 0.0168 (11) | 0.0052 (9) | −0.0032 (9) | −0.0019 (9) |
C9 | 0.0109 (10) | 0.0144 (10) | 0.0196 (11) | 0.0019 (9) | −0.0001 (9) | −0.0011 (9) |
C10 | 0.0118 (10) | 0.0127 (10) | 0.0175 (11) | 0.0018 (9) | 0.0011 (9) | 0.0008 (9) |
C11 | 0.0144 (11) | 0.0140 (11) | 0.0161 (11) | 0.0038 (9) | −0.0010 (9) | −0.0002 (9) |
C12 | 0.0160 (11) | 0.0173 (11) | 0.0196 (12) | 0.0005 (9) | −0.0013 (9) | 0.0011 (10) |
C13 | 0.0213 (12) | 0.0232 (12) | 0.0176 (12) | 0.0021 (10) | 0.0028 (10) | 0.0029 (10) |
C14 | 0.0261 (13) | 0.0228 (13) | 0.0175 (12) | 0.0046 (11) | −0.0040 (10) | −0.0010 (10) |
C15 | 0.0222 (12) | 0.0220 (13) | 0.0229 (13) | −0.0025 (11) | −0.0037 (10) | −0.0046 (10) |
C16 | 0.0175 (11) | 0.0191 (12) | 0.0216 (12) | −0.0019 (10) | 0.0008 (9) | 0.0003 (10) |
Fe1 | 0.00978 (17) | 0.01245 (17) | 0.01414 (17) | 0.00071 (12) | 0.00034 (12) | 0.00026 (13) |
N1 | 0.0414 (15) | 0.0375 (15) | 0.0163 (11) | −0.0077 (12) | −0.0016 (11) | −0.0064 (11) |
C1—C5 | 1.418 (4) | C8—C9 | 1.420 (3) |
C1—C2 | 1.423 (4) | C8—Fe1 | 2.045 (2) |
C1—Fe1 | 2.039 (2) | C8—H8 | 0.9500 |
C1—H1 | 0.9500 | C9—C10 | 1.435 (3) |
C2—C3 | 1.417 (4) | C9—Fe1 | 2.045 (2) |
C2—Fe1 | 2.034 (2) | C9—H9 | 0.9500 |
C2—H2 | 0.9500 | C10—C11 | 1.477 (3) |
C3—C4 | 1.423 (4) | C10—Fe1 | 2.057 (2) |
C3—Fe1 | 2.040 (2) | C11—C12 | 1.399 (3) |
C3—H3 | 0.9500 | C11—C16 | 1.402 (3) |
C4—C5 | 1.420 (3) | C12—C13 | 1.386 (3) |
C4—Fe1 | 2.044 (2) | C12—H12 | 0.9500 |
C4—H4 | 0.9500 | C13—C14 | 1.400 (4) |
C5—Fe1 | 2.043 (2) | C13—H13 | 0.9500 |
C5—H5 | 0.9500 | C14—C15 | 1.395 (4) |
C6—C7 | 1.417 (3) | C14—N1 | 1.396 (3) |
C6—C10 | 1.434 (3) | C15—C16 | 1.380 (4) |
C6—Fe1 | 2.036 (2) | C15—H15 | 0.9500 |
C6—H6 | 0.9500 | C16—H16 | 0.9500 |
C7—C8 | 1.422 (3) | N1—H1A | 0.84 (4) |
C7—Fe1 | 2.038 (2) | N1—H1B | 0.86 (4) |
C7—H7 | 0.9500 | ||
C5—C1—C2 | 107.8 (2) | C13—C12—C11 | 121.5 (2) |
C5—C1—Fe1 | 69.84 (14) | C13—C12—H12 | 119.2 |
C2—C1—Fe1 | 69.36 (14) | C11—C12—H12 | 119.2 |
C5—C1—H1 | 126.1 | C12—C13—C14 | 120.5 (2) |
C2—C1—H1 | 126.1 | C12—C13—H13 | 119.8 |
Fe1—C1—H1 | 126.3 | C14—C13—H13 | 119.8 |
C3—C2—C1 | 108.1 (2) | C15—C14—N1 | 121.5 (3) |
C3—C2—Fe1 | 69.88 (14) | C15—C14—C13 | 118.4 (2) |
C1—C2—Fe1 | 69.73 (14) | N1—C14—C13 | 120.1 (3) |
C3—C2—H2 | 126.0 | C16—C15—C14 | 120.8 (2) |
C1—C2—H2 | 126.0 | C16—C15—H15 | 119.6 |
Fe1—C2—H2 | 126.0 | C14—C15—H15 | 119.6 |
C2—C3—C4 | 108.0 (2) | C15—C16—C11 | 121.5 (2) |
C2—C3—Fe1 | 69.42 (14) | C15—C16—H16 | 119.3 |
C4—C3—Fe1 | 69.74 (13) | C11—C16—H16 | 119.3 |
C2—C3—H3 | 126.0 | C2—Fe1—C6 | 116.61 (10) |
C4—C3—H3 | 126.0 | C2—Fe1—C7 | 150.28 (11) |
Fe1—C3—H3 | 126.4 | C6—Fe1—C7 | 40.70 (9) |
C5—C4—C3 | 107.8 (2) | C2—Fe1—C1 | 40.91 (10) |
C5—C4—Fe1 | 69.66 (13) | C6—Fe1—C1 | 150.55 (10) |
C3—C4—Fe1 | 69.46 (14) | C7—Fe1—C1 | 167.68 (11) |
C5—C4—H4 | 126.1 | C2—Fe1—C3 | 40.70 (10) |
C3—C4—H4 | 126.1 | C6—Fe1—C3 | 107.04 (10) |
Fe1—C4—H4 | 126.4 | C7—Fe1—C3 | 117.30 (10) |
C1—C5—C4 | 108.2 (2) | C1—Fe1—C3 | 68.61 (10) |
C1—C5—Fe1 | 69.51 (14) | C2—Fe1—C5 | 68.56 (10) |
C4—C5—Fe1 | 69.69 (14) | C6—Fe1—C5 | 167.00 (10) |
C1—C5—H5 | 125.9 | C7—Fe1—C5 | 129.35 (10) |
C4—C5—H5 | 125.9 | C1—Fe1—C5 | 40.65 (10) |
Fe1—C5—H5 | 126.5 | C3—Fe1—C5 | 68.48 (10) |
C7—C6—C10 | 108.6 (2) | C2—Fe1—C4 | 68.61 (10) |
C7—C6—Fe1 | 69.75 (14) | C6—Fe1—C4 | 128.19 (10) |
C10—C6—Fe1 | 70.29 (13) | C7—Fe1—C4 | 108.23 (10) |
C7—C6—H6 | 125.7 | C1—Fe1—C4 | 68.54 (10) |
C10—C6—H6 | 125.7 | C3—Fe1—C4 | 40.80 (10) |
Fe1—C6—H6 | 125.9 | C5—Fe1—C4 | 40.65 (10) |
C6—C7—C8 | 108.2 (2) | C2—Fe1—C8 | 167.25 (10) |
C6—C7—Fe1 | 69.55 (13) | C6—Fe1—C8 | 68.60 (10) |
C8—C7—Fe1 | 69.89 (13) | C7—Fe1—C8 | 40.76 (10) |
C6—C7—H7 | 125.9 | C1—Fe1—C8 | 129.28 (10) |
C8—C7—H7 | 125.9 | C3—Fe1—C8 | 151.31 (10) |
Fe1—C7—H7 | 126.3 | C5—Fe1—C8 | 109.07 (10) |
C9—C8—C7 | 107.9 (2) | C4—Fe1—C8 | 118.36 (10) |
C9—C8—Fe1 | 69.70 (13) | C2—Fe1—C9 | 128.50 (10) |
C7—C8—Fe1 | 69.35 (13) | C6—Fe1—C9 | 68.64 (10) |
C9—C8—H8 | 126.1 | C7—Fe1—C9 | 68.47 (10) |
C7—C8—H8 | 126.1 | C1—Fe1—C9 | 108.39 (10) |
Fe1—C8—H8 | 126.5 | C3—Fe1—C9 | 166.38 (10) |
C8—C9—C10 | 108.7 (2) | C5—Fe1—C9 | 118.54 (10) |
C8—C9—Fe1 | 69.68 (13) | C4—Fe1—C9 | 151.82 (10) |
C10—C9—Fe1 | 69.95 (13) | C8—Fe1—C9 | 40.62 (9) |
C8—C9—H9 | 125.7 | C2—Fe1—C10 | 106.83 (10) |
C10—C9—H9 | 125.7 | C6—Fe1—C10 | 41.02 (9) |
Fe1—C9—H9 | 126.3 | C7—Fe1—C10 | 68.87 (10) |
C6—C10—C9 | 106.6 (2) | C1—Fe1—C10 | 117.16 (10) |
C6—C10—C11 | 127.9 (2) | C3—Fe1—C10 | 127.48 (10) |
C9—C10—C11 | 125.5 (2) | C5—Fe1—C10 | 151.29 (10) |
C6—C10—Fe1 | 68.69 (13) | C4—Fe1—C10 | 166.22 (10) |
C9—C10—Fe1 | 69.09 (13) | C8—Fe1—C10 | 68.86 (9) |
C11—C10—Fe1 | 127.96 (17) | C9—Fe1—C10 | 40.96 (9) |
C12—C11—C16 | 117.4 (2) | C14—N1—H1A | 117 (3) |
C12—C11—C10 | 121.0 (2) | C14—N1—H1B | 114 (3) |
C16—C11—C10 | 121.6 (2) | H1A—N1—H1B | 115 (4) |
Experimental details
Crystal data | |
Chemical formula | [Fe(C5H5)(C11H10N)] |
Mr | 277.14 |
Crystal system, space group | Orthorhombic, Pbca |
Temperature (K) | 100 |
a, b, c (Å) | 9.6762 (7), 8.0284 (6), 31.515 (2) |
V (Å3) | 2448.2 (3) |
Z | 8 |
Radiation type | Mo Kα |
µ (mm−1) | 1.21 |
Crystal size (mm) | 0.41 × 0.19 × 0.03 |
Data collection | |
Diffractometer | Bruker SMART APEX CCD area-detector |
Absorption correction | Multi-scan (SADABS in SAINT-Plus; Bruker, 2003) |
Tmin, Tmax | 0.712, 0.960 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 22095, 2821, 2679 |
Rint | 0.030 |
(sin θ/λ)max (Å−1) | 0.649 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.044, 0.095, 1.31 |
No. of reflections | 2821 |
No. of parameters | 171 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.57, −0.34 |
Computer programs: SMART (Bruker, 2002), SAINT-Plus (Bruker, 2003), SAINT-Plus, SHELXTL (Bruker, 2000), SHELXTL.
C10—C11 | 1.477 (3) | N1—H1A | 0.84 (4) |
C14—N1 | 1.396 (3) | N1—H1B | 0.86 (4) |
C14—N1—H1A | 117 (3) | H1A—N1—H1B | 115 (4) |
C14—N1—H1B | 114 (3) |
Ferrocene-containing dimers have received considerable interest over the years due to their potential applications in electrocatalysis (Togni & Hayashi, 1995; Sawamura & Ito, 1992; Nicolosi et al., 1994), ferromagnetism (Miller et al., 1996), chemical and biochemical sensing (Navarro et al., 2005; Brown et al., 2005; Okochi et al., 2005; Hickman et al., 1991) and self-assembled monolayer chemistry (Chidsey et al., 1990; Creager & Rowe, 1997). They are also of growing interest due to their unique structural, electrochemical and electronic structural properties. The production of dimeric ferrocenylamides has been hampered by the tedious synthesis of aminoferrocene, as it is difficult to produce in high enough yields to be useful in multi-step syntheses. In addition, the production of 1,1'-diaminoferrocene as the major product of most reaction pathways is a serious drawback. Although this compound can be purchased commercially, it is extremely expensive. Its phenyl derivative, the title compound p-ferrocenylaniline (I), on the other hand, can be easily produced in a two step synthesis from ferrocene by reaction with diazotated p-nitroaniline (Hu et al., 2001a), followed by the reduction of the resulting p-nitrophenylferrocene with Sn/HCl to produce the title compound p-ferrocenylaniline (Hu et al., 2001b). This paper presents the single-crystal structure of the title compound.
p-Ferrocenylaniline crystallizes in the orthorhombic space group Pbca with 8 molecules per unit cell (Figure 1). The conformation of the two Cp rings towards each other is close to eclipsed, and the substituted Cp and the phenyl ring are basically coplanar with a dihedral angle between the planes defined by C6 to C10 and C11 to C16 of 8.7 (2)°, a value not too different to that found for p-nitrophenylferrocene (13.5 (2)°, Zeller et al., 2004; see also: Roberts et al., 1988, Gallagher et al., 1997).
The hybridization of the amino group shows a tendency towards sp3 hybridization with angles between 114 and 117° (Table 1). The nitrogen atom is located slightly above the plane of the phenyl ring by 0.074 (3) Å. Together with the orientation of the amino hydrogen atoms, which are located below the phenyl plane by 0.11 (4) and 0.23 (4) Å, this allows for a conjugation of the nitrogen lone pair with the π electrons of the aromatic ring. This is in agreement with the 1H NMR spectral values, which are typical for ferrocenyl compounds with electron donating substituents: The cyclopentadienyl and phenyl protons have been shifted upfield from TMS, thus further conforming extensive π-overlap and electronic communication along the unsaturated backbone.
In contrast to aminoferrocene (Perrine et al., 2005) and also 1,1'-diaminoferrocene (Shafir et al., 2000), but similar to other structurally analyzed ferrocenyl amines (Rogers et al. 1998, Sunkel et al., 2000, Takaki et al., 1959) the title compound does not form hydrogen bonds in the solid state. Also no π-π stacking interactions are found in the structure: neighboring molecules are roughly perpendicular to each other with the C—H groups pointing towards the π-electrons of neighboring Cp and aromatic units (but at distances larger than the sum of the van-der-Waals radii). The packing and the lattice energy thus seems to be soley based on weak disperion interactions.