Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270113009049/wq3029sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270113009049/wq3029Isup2.hkl | |
MDL mol file https://doi.org/10.1107/S0108270113009049/wq3029Isup3.mol |
CCDC reference: 950416
For related literature, see: Capon et al. (2009); Cheng et al. (2005); Erdem et al. (2011); Gloaguen & Rauchfuss (2009); Pandey (1995); Seyferth et al. (1985); Shi & Gu (2013); Shi et al. (2012); Shi, Cheng, Fu, Gu & Wu (2013); Shi, Cheng, Yuan & Li (2011); Shi, Lai, Shen & Yuan (2011); Si et al. (2011); Song (2005); Song et al. (1995, 2006); Tard & Pickett (2009).
Under a nitrogen atmosphere, a mixture of (NEt4)(PPh2CS2) (1.167 g, 2.98 mmol) and Fe3(CO)12 (3.002 g, 5.96 mmol) in tetrahydrofuran (25 ml) was stirred for 30 min at room temperature to give a brown–red solution. The solution was cooled to 195 K, PhCOCl was added (0.419 g, 2.98 mmol) and the resulting mixture was stirred for 12 h at room temperature. The solvent was removed in vacuo and the residue was chromatographed using thin-layer chromatography on silica gel. Elution with petroleum ether gave an orange–brown band which was recrystallized from deoxygenated petroleum ether (333–363 K) and CH2Cl2 [Solvent ratio?] to afford an orange–brown solid of the title compound, (I) (yield 0.389 g, 10%). Analysis, calculated for C42H20Fe6O16P2S4: C 38.63, H 1.54%; found: C 38.56, H 1.55%. Spectroscopic analysis: IR (KBr disk, cm-1): ν(C≡O) 2062 (s), 1999 (vs, br); 1H NMR (300 MHz, CDCl3, TMS, δ, p.p.m.): 7.47–7.53 (m, 20H, 4C6H5); 31P NMR (121.6 MHz, CDCl3, 85% H3PO4, δ, p.p.m.): 2.75 (s); 13C NMR (75.5 MHz, CDCl3, TMS, δ, p.p.m.): 38.4 (d, 1JC—P = 22.2 Hz, 2 × PCS), 128.7, 128.8, 128.9, 130.4 (d, J = 9.7 Hz), 130.6, 131.1, 131.2, 131.3 (4 × C6H5), 211.6 (16 × C≡O).
All H atoms were located in difference maps and subsequently treated as riding in geometrically idealized positions, with aromatic C—H = 0.93 Å and Uiso(H) = 1.2Ueq(C).
Fe/S cluster complexes have attracted considerable attention, because of their interesting chemistry (Song, 2005) and in particular their practical applications, for example, as biomimetic models for the active sites of Fe–Fe hydrogenases (Gloaguen & Rauchfuss, 2009; Capon et al., 2009). However, so far, few efficient electrocatalysts have been obtained and the mechanism of the natural production/uptake of hydrogen remains unclear. Therefore, novel structural and chemical models are still necessary to gain a better understanding of the protonation mechanisms implied at the molecular level (Erdem et al., 2011; Tard & Pickett, 2009; Song et al., 2006). In view of the lack of reports on heteroallyl anions of the general type G—C(═Y)—Z- (G = potential donor group; Y = S or Se; Z = S, Se, NR or CHR) with iron carbonyls, we have initiated the project on reactions of heteroallyl anions G—C(═Y)—Z- with iron carbonyls in order to develop the synthetic methodology of Fe/S cluster complexes for model compounds (Shi & Gu, 2013; Shi, Cheng et al., 2013; Shi et al., 2012). As part of this on-going project, we report herein the synthesis and crystal structure of a novel hexairon cluster with the unprecedented Ph2PCS ligand (Shi, Cheng et al., 2011; Shi, Lai et al., 2011).
Under an N2 atmosphere, the reaction of Fe3(CO)12 with (NEt4)[Ph2PCS2] in the presence of PhCOCl at room temperature leads to the formation of (I) (see Scheme 1). At the present stage, the role of PhCOCl in the reaction is unclear. However, to our knowledge, this novel six-nuclear iron cluster incorporating the unique diphenylphosphinothioacyl ligand Ph2PCS is unprecedented.
The molecule of (I) (Fig. 1) lies across a crystallographic center of inversion at the mid-point of the disulfide bond. The S2 ligand links two (Ph2PCS)Fe3(CO)8 units in a µ4-κ2S:κ2S' pattern. Each Ph2PCS group shows a µ3-κ1P:κ2C:κ2S coordination mode with donation of seven electrons to an Fe3(CO)8 core in which each Fe atom obeys the 18-electron rule. Furthermore, the Fe1 atom with three terminal carbonyls possesses six-coordinate distorted octahedral geometry. Similarly, the Fe3 atom with three terminal carbonyls shows octahedral geometry, with an axial angle of 171.64 (10)° for P1—Fe3—C6 (Table 1). However, the Fe2 atom with two carbonyls has a seven-coordinate distorted octahedral geometry. One of two CO ligands (C4═O4) at the Fe2 atom displays a semi-bridging coordination fashion, with a C4···Fe1 separation of 2.589 (3) Å and an O4—C4—Fe2 angle of 168.3 (2)°. The Fe1—Fe2—Fe3 angle is 125.571 (15)°, indicating that these atoms are not colinear.
Although the Fe1—Fe2 bond is shorter than Fe2—Fe3, both lie within the range previously noted for single bonds (2.43–2.88 Å; Shi et al., 2012). Notably, the Fe1—C9 bond is significantly shorter than that of Fe2—C9; the latter falls within the previously observed range of 2.0–2.2 Å and therefore agrees with a single bond. Atoms S1 and S2 each bridge two Fe atoms in an asymmetrical fashion (Table 1). The C9—S1 has double-bond character as it is between the typical single bond of 1.81 Å and the typical double bond of 1.56 Å in CS2 (Pandey, 1995). In accordance with this fact, the C9—P1 bond is markedly shorter than a normal C—P single bond of 1.82 Å. As well as the CS group doubly bridging atoms Fe1 and Fe2, atom P1 of the Ph2PCS ligand binds to atom Fe3 with a normal Fe—P bond length. Therefore, the above bonding mode of the Ph2PCS ligand suggests that (I) can be viewed as a hybrid of the two resonance forms shown in Scheme 2.
As noted for (µ4-S2)[(µ-PhS)Fe2(CO)6]2 (Seyferth et al., 1985) and for (µ4-S2)[(µ-EtS)Fe2(CO)6]2 crystallized in P1 (Si et al., 2011), the S2 ligand of (I) bridges the two subclusters via an equatorial S—S bond with respect to the Fe2SCP core [S2i—S2···C9 = 148.24 (4)° and S2i—S2···P1 = 157.89 (3)°; symmetry code: (i) -x + 1, -y + 1, -z + 1]. However, two subclusters of (µ4-S2)[(µ-EtS)Fe2(CO)6]2 crystallized in P21/c (Cheng et al., 2005) are connected through an axial S—S bond with respect to the butterfly Fe2S2 core (Cheng et al., 2005; Song et al., 1995). The bond distance of the two S atoms in (I) is 2.1490 (9) Å, the corresponding values of the above complexes are 2.106 (3), 2.113 (2) and 2.1294 (14) Å.
Interestingly, the supramolecular assembly in (I) depends on the combination of: (a) an S1···Cg1ii contact of 3.433 Å [symmetry code: (ii) -x+1, -y+1, -z+2; Cg1 represents the centroid of the C10–C15 benzene ring], (b) an aromatic Cg1···Cg1iii π–π stacking interaction [symmetry code: (iii) -x+2, -y, -z+2] involving the C10–C15 benzene rings, with an interplanar spacing of 3.5481 (11) Å, a ring-centroid separation of 3.7721 (17) Å and a ring-centroid offset of 1.281 Å, and (c) a C17—H17···O2iv [symmetry code: (iv) -x+1, -y, -z+2] hydrogen bond (Table 2). The contact forms a chain in the [001] direction. Furthermore, the hydrogen bond along with the contact described above generates a sheet parallel to the bc plance. Finally, the π–π stacking interaction makes the sheet packed along the a axis to result in the formation of a three-dimensional supramolecular structure.
Unlike the above crystalline state, the molecule of (I) in CDCl3 exhibits fluxionality on the NMR timescale, with only one carbonyl signal observed in the 13C NMR spectrum (Shi & Gu, 2013).
For related literature, see: Capon et al. (2009); Cheng et al. (2005); Erdem et al. (2011); Gloaguen & Rauchfuss (2009); Pandey (1995); Seyferth et al. (1985); Shi & Gu (2013); Shi et al. (2012); Shi, Cheng, Fu, Gu & Wu (2013); Shi, Cheng, Yuan & Li (2011); Shi, Lai, Shen & Yuan (2011); Si et al. (2011); Song (2005); Song et al. (1995, 2006); Tard & Pickett (2009).
Data collection: SMART (Bruker, 2002); cell refinement: SAINT-Plus (Bruker, 2003); data reduction: SAINT-Plus (Bruker, 2003); program(s) used to solve structure: SIR2004 (Burla et al., 2005); program(s) used to refine structure: SHELXTL (Sheldrick, 2008); molecular graphics: PLATON (Spek, 2009) and WinGX (Farrugia, 2012); software used to prepare material for publication: publCIF (Westrip, 2010).
[Fe6(C13H10PS)2(S2)(CO)16] | Z = 1 |
Mr = 1305.90 | F(000) = 650 |
Triclinic, P1 | Dx = 1.765 Mg m−3 |
a = 10.5129 (13) Å | Mo Kα radiation, λ = 0.71073 Å |
b = 10.5849 (13) Å | Cell parameters from 4455 reflections |
c = 12.7572 (16) Å | θ = 1.6–27.5° |
α = 83.6258 (14)° | µ = 2.03 mm−1 |
β = 87.7599 (11)° | T = 296 K |
γ = 60.5657 (14)° | Block, orange–red |
V = 1228.5 (3) Å3 | 0.20 × 0.18 × 0.18 mm |
Bruker SMART APEX CCD area-detector diffractometer | 5486 independent reflections |
Radiation source: fine-focus sealed tube | 4453 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.017 |
ω and φ scans | θmax = 27.5°, θmin = 1.6° |
Absorption correction: multi-scan (SADABS; Sheldrick, 2004) | h = −12→13 |
Tmin = 0.672, Tmax = 0.691 | k = −13→13 |
10572 measured reflections | l = −16→16 |
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)] = 0.027 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.071 | H-atom parameters constrained |
S = 1.01 | w = 1/[σ2(Fo2) + (0.0348P)2 + 0.4153P] where P = (Fo2 + 2Fc2)/3 |
5486 reflections | (Δ/σ)max = 0.001 |
316 parameters | Δρmax = 0.37 e Å−3 |
0 restraints | Δρmin = −0.32 e Å−3 |
[Fe6(C13H10PS)2(S2)(CO)16] | γ = 60.5657 (14)° |
Mr = 1305.90 | V = 1228.5 (3) Å3 |
Triclinic, P1 | Z = 1 |
a = 10.5129 (13) Å | Mo Kα radiation |
b = 10.5849 (13) Å | µ = 2.03 mm−1 |
c = 12.7572 (16) Å | T = 296 K |
α = 83.6258 (14)° | 0.20 × 0.18 × 0.18 mm |
β = 87.7599 (11)° |
Bruker SMART APEX CCD area-detector diffractometer | 5486 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 2004) | 4453 reflections with I > 2σ(I) |
Tmin = 0.672, Tmax = 0.691 | Rint = 0.017 |
10572 measured reflections |
R[F2 > 2σ(F2)] = 0.027 | 0 restraints |
wR(F2) = 0.071 | H-atom parameters constrained |
S = 1.01 | Δρmax = 0.37 e Å−3 |
5486 reflections | Δρmin = −0.32 e Å−3 |
316 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 | 0.0994 (3) | 0.4583 (3) | 0.8216 (2) | 0.0496 (6) | |
C2 | 0.3294 (3) | 0.2307 (3) | 0.9242 (2) | 0.0476 (6) | |
C3 | 0.3156 (3) | 0.2258 (3) | 0.7214 (2) | 0.0533 (7) | |
C4 | 0.2271 (3) | 0.5252 (3) | 0.63452 (19) | 0.0451 (6) | |
C5 | 0.2988 (3) | 0.7179 (3) | 0.66234 (18) | 0.0464 (6) | |
C6 | 0.6080 (3) | 0.6517 (3) | 0.60315 (19) | 0.0473 (6) | |
C7 | 0.8443 (3) | 0.3940 (3) | 0.65607 (18) | 0.0456 (6) | |
C8 | 0.6384 (3) | 0.5652 (3) | 0.79944 (18) | 0.0409 (6) | |
C9 | 0.4811 (2) | 0.3519 (2) | 0.80440 (15) | 0.0294 (4) | |
C10 | 0.7637 (2) | 0.2312 (2) | 0.91215 (16) | 0.0333 (5) | |
C11 | 0.8868 (3) | 0.2435 (3) | 0.9254 (2) | 0.0468 (6) | |
H11 | 0.9210 | 0.2815 | 0.8691 | 0.056* | |
C12 | 0.9599 (3) | 0.1991 (3) | 1.0225 (2) | 0.0552 (7) | |
H12 | 1.0423 | 0.2084 | 1.0312 | 0.066* | |
C13 | 0.9104 (3) | 0.1419 (3) | 1.10540 (19) | 0.0527 (7) | |
H13 | 0.9597 | 0.1115 | 1.1701 | 0.063* | |
C14 | 0.7885 (3) | 0.1294 (3) | 1.09293 (19) | 0.0512 (7) | |
H14 | 0.7555 | 0.0903 | 1.1494 | 0.061* | |
C15 | 0.7139 (3) | 0.1744 (3) | 0.99702 (17) | 0.0421 (6) | |
H15 | 0.6304 | 0.1666 | 0.9894 | 0.051* | |
C16 | 0.7335 (2) | 0.1134 (2) | 0.72662 (16) | 0.0320 (5) | |
C17 | 0.7008 (3) | 0.0096 (3) | 0.7757 (2) | 0.0466 (6) | |
H17 | 0.6448 | 0.0289 | 0.8361 | 0.056* | |
C18 | 0.7509 (4) | −0.1229 (3) | 0.7353 (3) | 0.0596 (8) | |
H18 | 0.7306 | −0.1930 | 0.7696 | 0.071* | |
C19 | 0.8307 (3) | −0.1504 (3) | 0.6446 (3) | 0.0592 (8) | |
H19 | 0.8618 | −0.2380 | 0.6163 | 0.071* | |
C20 | 0.8647 (3) | −0.0491 (3) | 0.5956 (2) | 0.0589 (7) | |
H20 | 0.9206 | −0.0692 | 0.5350 | 0.071* | |
C21 | 0.8159 (3) | 0.0833 (3) | 0.6359 (2) | 0.0463 (6) | |
H21 | 0.8386 | 0.1520 | 0.6020 | 0.056* | |
Fe1 | 0.29735 (4) | 0.35537 (4) | 0.80964 (2) | 0.03537 (9) | |
Fe2 | 0.37784 (3) | 0.52361 (3) | 0.69573 (2) | 0.03015 (8) | |
Fe3 | 0.65129 (3) | 0.48071 (3) | 0.68219 (2) | 0.03075 (8) | |
O1 | −0.0223 (2) | 0.5243 (3) | 0.8346 (2) | 0.0795 (7) | |
O2 | 0.3507 (3) | 0.1492 (3) | 0.99583 (17) | 0.0785 (7) | |
O3 | 0.3312 (3) | 0.1400 (3) | 0.6681 (2) | 0.0940 (8) | |
O4 | 0.1357 (2) | 0.5379 (3) | 0.58043 (15) | 0.0667 (6) | |
O5 | 0.2457 (3) | 0.8413 (2) | 0.64475 (17) | 0.0751 (7) | |
O6 | 0.5864 (3) | 0.7589 (2) | 0.55826 (17) | 0.0789 (7) | |
O7 | 0.9669 (2) | 0.3382 (3) | 0.64407 (17) | 0.0749 (7) | |
O8 | 0.6274 (3) | 0.6241 (2) | 0.87131 (15) | 0.0622 (5) | |
P1 | 0.66956 (6) | 0.28395 (6) | 0.78435 (4) | 0.02828 (12) | |
S1 | 0.37012 (6) | 0.50075 (6) | 0.87151 (4) | 0.03457 (13) | |
S2 | 0.53376 (6) | 0.42283 (5) | 0.56932 (4) | 0.02771 (11) |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0403 (15) | 0.0539 (16) | 0.0554 (15) | −0.0259 (13) | 0.0015 (12) | 0.0048 (12) |
C2 | 0.0462 (15) | 0.0524 (15) | 0.0490 (14) | −0.0294 (13) | 0.0038 (11) | 0.0017 (12) |
C3 | 0.0494 (17) | 0.0588 (17) | 0.0579 (16) | −0.0315 (14) | −0.0036 (13) | −0.0028 (14) |
C4 | 0.0360 (13) | 0.0605 (16) | 0.0366 (12) | −0.0233 (12) | 0.0005 (10) | 0.0020 (11) |
C5 | 0.0534 (16) | 0.0439 (14) | 0.0321 (12) | −0.0178 (12) | 0.0040 (11) | 0.0016 (10) |
C6 | 0.0684 (18) | 0.0541 (15) | 0.0379 (12) | −0.0449 (14) | −0.0139 (12) | 0.0039 (11) |
C7 | 0.0464 (16) | 0.0635 (17) | 0.0355 (12) | −0.0347 (14) | −0.0058 (11) | 0.0034 (11) |
C8 | 0.0516 (15) | 0.0456 (13) | 0.0344 (12) | −0.0314 (12) | −0.0023 (10) | 0.0005 (10) |
C9 | 0.0292 (11) | 0.0323 (10) | 0.0251 (9) | −0.0147 (9) | −0.0010 (8) | 0.0019 (8) |
C10 | 0.0331 (12) | 0.0321 (11) | 0.0282 (10) | −0.0111 (9) | −0.0059 (8) | −0.0006 (8) |
C11 | 0.0396 (14) | 0.0593 (16) | 0.0411 (13) | −0.0246 (13) | −0.0074 (11) | 0.0003 (12) |
C12 | 0.0384 (15) | 0.0716 (19) | 0.0513 (15) | −0.0226 (14) | −0.0134 (12) | −0.0076 (14) |
C13 | 0.0491 (16) | 0.0522 (15) | 0.0340 (13) | −0.0062 (13) | −0.0153 (11) | −0.0042 (11) |
C14 | 0.0626 (18) | 0.0502 (15) | 0.0298 (12) | −0.0202 (14) | −0.0055 (11) | 0.0031 (11) |
C15 | 0.0457 (15) | 0.0489 (14) | 0.0319 (11) | −0.0242 (12) | −0.0056 (10) | 0.0020 (10) |
C16 | 0.0281 (11) | 0.0322 (11) | 0.0318 (10) | −0.0119 (9) | −0.0046 (8) | −0.0009 (8) |
C17 | 0.0519 (16) | 0.0418 (13) | 0.0479 (14) | −0.0250 (12) | 0.0080 (12) | −0.0049 (11) |
C18 | 0.066 (2) | 0.0441 (15) | 0.076 (2) | −0.0329 (15) | 0.0055 (16) | −0.0072 (14) |
C19 | 0.0553 (18) | 0.0416 (14) | 0.076 (2) | −0.0173 (13) | 0.0007 (15) | −0.0199 (14) |
C20 | 0.0564 (18) | 0.0510 (16) | 0.0589 (17) | −0.0171 (14) | 0.0140 (14) | −0.0167 (13) |
C21 | 0.0465 (15) | 0.0405 (13) | 0.0469 (13) | −0.0179 (12) | 0.0105 (11) | −0.0061 (11) |
Fe1 | 0.03145 (18) | 0.04054 (18) | 0.03581 (17) | −0.02000 (15) | 0.00073 (13) | 0.00124 (14) |
Fe2 | 0.02970 (17) | 0.03294 (16) | 0.02477 (15) | −0.01395 (14) | −0.00052 (11) | 0.00188 (12) |
Fe3 | 0.03544 (18) | 0.03727 (17) | 0.02560 (15) | −0.02326 (15) | −0.00425 (12) | 0.00236 (12) |
O1 | 0.0350 (12) | 0.0772 (15) | 0.117 (2) | −0.0224 (11) | 0.0096 (12) | −0.0033 (14) |
O2 | 0.0987 (19) | 0.0734 (15) | 0.0654 (14) | −0.0501 (14) | −0.0020 (12) | 0.0257 (12) |
O3 | 0.112 (2) | 0.0918 (19) | 0.101 (2) | −0.0610 (17) | 0.0034 (16) | −0.0424 (16) |
O4 | 0.0493 (12) | 0.1090 (18) | 0.0451 (10) | −0.0434 (12) | −0.0117 (9) | 0.0062 (11) |
O5 | 0.1011 (18) | 0.0373 (11) | 0.0612 (13) | −0.0166 (11) | 0.0063 (12) | 0.0051 (9) |
O6 | 0.129 (2) | 0.0676 (14) | 0.0668 (13) | −0.0721 (15) | −0.0321 (13) | 0.0239 (11) |
O7 | 0.0401 (12) | 0.1144 (19) | 0.0680 (14) | −0.0380 (13) | 0.0007 (10) | 0.0003 (13) |
O8 | 0.0908 (16) | 0.0732 (13) | 0.0436 (10) | −0.0544 (13) | 0.0047 (10) | −0.0174 (10) |
P1 | 0.0283 (3) | 0.0315 (3) | 0.0250 (2) | −0.0153 (2) | −0.0031 (2) | 0.0017 (2) |
S1 | 0.0378 (3) | 0.0372 (3) | 0.0270 (2) | −0.0175 (2) | 0.0027 (2) | −0.0022 (2) |
S2 | 0.0299 (3) | 0.0313 (3) | 0.0227 (2) | −0.0162 (2) | −0.00243 (19) | 0.00112 (19) |
C1—O1 | 1.133 (3) | C12—H12 | 0.9300 |
C1—Fe1 | 1.824 (3) | C13—C14 | 1.368 (4) |
C2—O2 | 1.131 (3) | C13—H13 | 0.9300 |
C2—Fe1 | 1.779 (3) | C14—C15 | 1.385 (3) |
C3—O3 | 1.138 (4) | C14—H14 | 0.9300 |
C3—Fe1 | 1.804 (3) | C15—H15 | 0.9300 |
C4—O4 | 1.150 (3) | C16—C17 | 1.385 (3) |
C4—Fe2 | 1.786 (3) | C16—C21 | 1.387 (3) |
C5—O5 | 1.138 (3) | C16—P1 | 1.821 (2) |
C5—Fe2 | 1.805 (3) | C17—C18 | 1.386 (4) |
C6—O6 | 1.131 (3) | C17—H17 | 0.9300 |
C6—Fe3 | 1.822 (2) | C18—C19 | 1.374 (4) |
C7—O7 | 1.136 (3) | C18—H18 | 0.9300 |
C7—Fe3 | 1.804 (3) | C19—C20 | 1.370 (4) |
C8—O8 | 1.136 (3) | C19—H19 | 0.9300 |
C8—Fe3 | 1.794 (3) | C20—C21 | 1.388 (4) |
C9—S1 | 1.730 (2) | C20—H20 | 0.9300 |
C9—P1 | 1.763 (2) | C21—H21 | 0.9300 |
C9—Fe1 | 1.912 (2) | Fe1—S1 | 2.2473 (7) |
C9—Fe2 | 2.0057 (19) | Fe1—Fe2 | 2.6094 (5) |
C10—C11 | 1.381 (3) | Fe2—S2 | 2.2095 (6) |
C10—C15 | 1.389 (3) | Fe2—S1 | 2.2313 (6) |
C10—P1 | 1.825 (2) | Fe2—Fe3 | 2.6825 (6) |
C11—C12 | 1.392 (3) | Fe3—S2 | 2.2481 (6) |
C11—H11 | 0.9300 | Fe3—P1 | 2.2575 (6) |
C12—C13 | 1.372 (4) | S2—S2i | 2.1490 (9) |
Fe1···C4 | 2.589 (3) | C6···C7 | 2.670 (4) |
C1···C2 | 2.681 (4) | C6···C8 | 2.545 (3) |
C1···C3 | 2.798 (4) | C7···C8 | 2.808 (4) |
C2···C3 | 2.605 (4) | Cg1···S1ii | 3.433 |
C4···C5 | 2.559 (4) | Cg1···Cg1iii | 3.7721 (17) |
O1—C1—Fe1 | 176.0 (3) | C3—Fe1—S1 | 151.54 (9) |
O2—C2—Fe1 | 178.6 (3) | C1—Fe1—S1 | 102.64 (9) |
O3—C3—Fe1 | 177.4 (3) | C9—Fe1—S1 | 48.32 (7) |
O4—C4—Fe2 | 168.3 (2) | C2—Fe1—Fe2 | 147.42 (9) |
O5—C5—Fe2 | 177.3 (2) | C3—Fe1—Fe2 | 103.46 (9) |
O6—C6—Fe3 | 175.8 (2) | C1—Fe1—Fe2 | 107.51 (8) |
O7—C7—Fe3 | 177.1 (2) | C9—Fe1—Fe2 | 49.79 (6) |
O8—C8—Fe3 | 177.2 (2) | S1—Fe1—Fe2 | 54.078 (18) |
S1—C9—P1 | 125.06 (13) | C4—Fe2—C5 | 90.92 (13) |
S1—C9—Fe1 | 76.02 (9) | C4—Fe2—C9 | 112.45 (10) |
P1—C9—Fe1 | 158.35 (13) | C5—Fe2—C9 | 147.49 (10) |
S1—C9—Fe2 | 72.94 (8) | C4—Fe2—S2 | 95.43 (8) |
P1—C9—Fe2 | 106.20 (10) | C5—Fe2—S2 | 105.56 (8) |
Fe1—C9—Fe2 | 83.48 (8) | C9—Fe2—S2 | 94.78 (6) |
C11—C10—C15 | 119.1 (2) | C4—Fe2—S1 | 112.89 (8) |
C11—C10—P1 | 120.89 (17) | C5—Fe2—S1 | 103.16 (8) |
C15—C10—P1 | 119.94 (18) | C9—Fe2—S1 | 47.82 (6) |
C10—C11—C12 | 120.3 (2) | S2—Fe2—S1 | 138.93 (2) |
C10—C11—H11 | 119.8 | C4—Fe2—Fe1 | 69.28 (8) |
C12—C11—H11 | 119.8 | C5—Fe2—Fe1 | 134.91 (9) |
C13—C12—C11 | 120.0 (3) | C9—Fe2—Fe1 | 46.73 (6) |
C13—C12—H12 | 120.0 | S2—Fe2—Fe1 | 116.01 (2) |
C11—C12—H12 | 120.0 | S1—Fe2—Fe1 | 54.651 (18) |
C14—C13—C12 | 120.1 (2) | C4—Fe2—Fe3 | 148.61 (8) |
C14—C13—H13 | 120.0 | C5—Fe2—Fe3 | 92.58 (9) |
C12—C13—H13 | 120.0 | C9—Fe2—Fe3 | 79.19 (6) |
C13—C14—C15 | 120.6 (3) | S2—Fe2—Fe3 | 53.663 (17) |
C13—C14—H14 | 119.7 | S1—Fe2—Fe3 | 96.620 (19) |
C15—C14—H14 | 119.7 | Fe1—Fe2—Fe3 | 125.571 (15) |
C14—C15—C10 | 119.9 (2) | C8—Fe3—C7 | 102.63 (12) |
C14—C15—H15 | 120.0 | C8—Fe3—C6 | 89.46 (11) |
C10—C15—H15 | 120.0 | C7—Fe3—C6 | 94.82 (12) |
C17—C16—C21 | 118.9 (2) | C8—Fe3—S2 | 146.05 (9) |
C17—C16—P1 | 119.03 (18) | C7—Fe3—S2 | 110.90 (8) |
C21—C16—P1 | 122.02 (18) | C6—Fe3—S2 | 92.85 (8) |
C16—C17—C18 | 120.5 (2) | C8—Fe3—P1 | 88.98 (7) |
C16—C17—H17 | 119.7 | C7—Fe3—P1 | 93.53 (8) |
C18—C17—H17 | 119.7 | C6—Fe3—P1 | 171.64 (10) |
C19—C18—C17 | 119.9 (3) | S2—Fe3—P1 | 83.90 (2) |
C19—C18—H18 | 120.1 | C8—Fe3—Fe2 | 93.75 (8) |
C17—C18—H18 | 120.1 | C7—Fe3—Fe2 | 159.76 (9) |
C20—C19—C18 | 120.2 (3) | C6—Fe3—Fe2 | 97.16 (9) |
C20—C19—H19 | 119.9 | S2—Fe3—Fe2 | 52.347 (17) |
C18—C19—H19 | 119.9 | P1—Fe3—Fe2 | 74.750 (18) |
C19—C20—C21 | 120.2 (3) | C9—P1—C16 | 105.72 (10) |
C19—C20—H20 | 119.9 | C9—P1—C10 | 109.13 (10) |
C21—C20—H20 | 119.9 | C16—P1—C10 | 104.94 (10) |
C16—C21—C20 | 120.1 (2) | C9—P1—Fe3 | 97.17 (7) |
C16—C21—H21 | 119.9 | C16—P1—Fe3 | 119.23 (7) |
C20—C21—H21 | 119.9 | C10—P1—Fe3 | 119.30 (8) |
C2—Fe1—C3 | 93.30 (13) | C9—S1—Fe2 | 59.24 (6) |
C2—Fe1—C1 | 96.18 (12) | C9—S1—Fe1 | 55.66 (7) |
C3—Fe1—C1 | 100.99 (13) | Fe2—S1—Fe1 | 71.27 (2) |
C2—Fe1—C9 | 99.20 (10) | S2i—S2—Fe2 | 108.19 (4) |
C3—Fe1—C9 | 104.78 (11) | S2i—S2—Fe3 | 109.71 (4) |
C1—Fe1—C9 | 149.02 (11) | Fe2—S2—Fe3 | 73.99 (2) |
C2—Fe1—S1 | 99.68 (9) |
Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) −x+1, −y+1, −z+2; (iii) −x+2, −y, −z+2. |
D—H···A | D—H | H···A | D···A | D—H···A |
C17—H17···O2iv | 0.93 | 2.68 | 3.361 (3) | 131 |
Symmetry code: (iv) −x+1, −y, −z+2. |
Experimental details
Crystal data | |
Chemical formula | [Fe6(C13H10PS)2(S2)(CO)16] |
Mr | 1305.90 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 296 |
a, b, c (Å) | 10.5129 (13), 10.5849 (13), 12.7572 (16) |
α, β, γ (°) | 83.6258 (14), 87.7599 (11), 60.5657 (14) |
V (Å3) | 1228.5 (3) |
Z | 1 |
Radiation type | Mo Kα |
µ (mm−1) | 2.03 |
Crystal size (mm) | 0.20 × 0.18 × 0.18 |
Data collection | |
Diffractometer | Bruker SMART APEX CCD area-detector |
Absorption correction | Multi-scan (SADABS; Sheldrick, 2004) |
Tmin, Tmax | 0.672, 0.691 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 10572, 5486, 4453 |
Rint | 0.017 |
(sin θ/λ)max (Å−1) | 0.649 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.027, 0.071, 1.01 |
No. of reflections | 5486 |
No. of parameters | 316 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.37, −0.32 |
Computer programs: SMART (Bruker, 2002), SAINT-Plus (Bruker, 2003), SIR2004 (Burla et al., 2005), SHELXTL (Sheldrick, 2008), PLATON (Spek, 2009) and WinGX (Farrugia, 2012), publCIF (Westrip, 2010).
C9—S1 | 1.730 (2) | Fe2—S2 | 2.2095 (6) |
C9—P1 | 1.763 (2) | Fe2—S1 | 2.2313 (6) |
C9—Fe1 | 1.912 (2) | Fe2—Fe3 | 2.6825 (6) |
C9—Fe2 | 2.0057 (19) | Fe3—S2 | 2.2481 (6) |
Fe1—S1 | 2.2473 (7) | Fe3—P1 | 2.2575 (6) |
Fe1—Fe2 | 2.6094 (5) | S2—S2i | 2.1490 (9) |
Fe1···C4 | 2.589 (3) | C6···C7 | 2.670 (4) |
C1···C2 | 2.681 (4) | C6···C8 | 2.545 (3) |
C1···C3 | 2.798 (4) | C7···C8 | 2.808 (4) |
C2···C3 | 2.605 (4) | Cg1···S1ii | 3.433 |
C4···C5 | 2.559 (4) | Cg1···Cg1iii | 3.7721 (17) |
O4—C4—Fe2 | 168.3 (2) | Fe1—C9—Fe2 | 83.48 (8) |
O5—C5—Fe2 | 177.3 (2) | Fe1—Fe2—Fe3 | 125.571 (15) |
S1—C9—Fe1 | 76.02 (9) | Fe2—S1—Fe1 | 71.27 (2) |
S1—C9—Fe2 | 72.94 (8) | Fe2—S2—Fe3 | 73.99 (2) |
Symmetry codes: (i) −x+1, −y+1, −z+1; (ii) −x+1, −y+1, −z+2; (iii) −x+2, −y, −z+2. |
D—H···A | D—H | H···A | D···A | D—H···A |
C17—H17···O2iv | 0.93 | 2.68 | 3.361 (3) | 130.9 |
Symmetry code: (iv) −x+1, −y, −z+2. |
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Fe/S cluster complexes have attracted considerable attention, because of their interesting chemistry (Song, 2005) and in particular their practical applications, for example, as biomimetic models for the active sites of Fe–Fe hydrogenases (Gloaguen & Rauchfuss, 2009; Capon et al., 2009). However, so far, few efficient electrocatalysts have been obtained and the mechanism of the natural production/uptake of hydrogen remains unclear. Therefore, novel structural and chemical models are still necessary to gain a better understanding of the protonation mechanisms implied at the molecular level (Erdem et al., 2011; Tard & Pickett, 2009; Song et al., 2006). In view of the lack of reports on heteroallyl anions of the general type G—C(═Y)—Z- (G = potential donor group; Y = S or Se; Z = S, Se, NR or CHR) with iron carbonyls, we have initiated the project on reactions of heteroallyl anions G—C(═Y)—Z- with iron carbonyls in order to develop the synthetic methodology of Fe/S cluster complexes for model compounds (Shi & Gu, 2013; Shi, Cheng et al., 2013; Shi et al., 2012). As part of this on-going project, we report herein the synthesis and crystal structure of a novel hexairon cluster with the unprecedented Ph2PCS ligand (Shi, Cheng et al., 2011; Shi, Lai et al., 2011).
Under an N2 atmosphere, the reaction of Fe3(CO)12 with (NEt4)[Ph2PCS2] in the presence of PhCOCl at room temperature leads to the formation of (I) (see Scheme 1). At the present stage, the role of PhCOCl in the reaction is unclear. However, to our knowledge, this novel six-nuclear iron cluster incorporating the unique diphenylphosphinothioacyl ligand Ph2PCS is unprecedented.
The molecule of (I) (Fig. 1) lies across a crystallographic center of inversion at the mid-point of the disulfide bond. The S2 ligand links two (Ph2PCS)Fe3(CO)8 units in a µ4-κ2S:κ2S' pattern. Each Ph2PCS group shows a µ3-κ1P:κ2C:κ2S coordination mode with donation of seven electrons to an Fe3(CO)8 core in which each Fe atom obeys the 18-electron rule. Furthermore, the Fe1 atom with three terminal carbonyls possesses six-coordinate distorted octahedral geometry. Similarly, the Fe3 atom with three terminal carbonyls shows octahedral geometry, with an axial angle of 171.64 (10)° for P1—Fe3—C6 (Table 1). However, the Fe2 atom with two carbonyls has a seven-coordinate distorted octahedral geometry. One of two CO ligands (C4═O4) at the Fe2 atom displays a semi-bridging coordination fashion, with a C4···Fe1 separation of 2.589 (3) Å and an O4—C4—Fe2 angle of 168.3 (2)°. The Fe1—Fe2—Fe3 angle is 125.571 (15)°, indicating that these atoms are not colinear.
Although the Fe1—Fe2 bond is shorter than Fe2—Fe3, both lie within the range previously noted for single bonds (2.43–2.88 Å; Shi et al., 2012). Notably, the Fe1—C9 bond is significantly shorter than that of Fe2—C9; the latter falls within the previously observed range of 2.0–2.2 Å and therefore agrees with a single bond. Atoms S1 and S2 each bridge two Fe atoms in an asymmetrical fashion (Table 1). The C9—S1 has double-bond character as it is between the typical single bond of 1.81 Å and the typical double bond of 1.56 Å in CS2 (Pandey, 1995). In accordance with this fact, the C9—P1 bond is markedly shorter than a normal C—P single bond of 1.82 Å. As well as the CS group doubly bridging atoms Fe1 and Fe2, atom P1 of the Ph2PCS ligand binds to atom Fe3 with a normal Fe—P bond length. Therefore, the above bonding mode of the Ph2PCS ligand suggests that (I) can be viewed as a hybrid of the two resonance forms shown in Scheme 2.
As noted for (µ4-S2)[(µ-PhS)Fe2(CO)6]2 (Seyferth et al., 1985) and for (µ4-S2)[(µ-EtS)Fe2(CO)6]2 crystallized in P1 (Si et al., 2011), the S2 ligand of (I) bridges the two subclusters via an equatorial S—S bond with respect to the Fe2SCP core [S2i—S2···C9 = 148.24 (4)° and S2i—S2···P1 = 157.89 (3)°; symmetry code: (i) -x + 1, -y + 1, -z + 1]. However, two subclusters of (µ4-S2)[(µ-EtS)Fe2(CO)6]2 crystallized in P21/c (Cheng et al., 2005) are connected through an axial S—S bond with respect to the butterfly Fe2S2 core (Cheng et al., 2005; Song et al., 1995). The bond distance of the two S atoms in (I) is 2.1490 (9) Å, the corresponding values of the above complexes are 2.106 (3), 2.113 (2) and 2.1294 (14) Å.
Interestingly, the supramolecular assembly in (I) depends on the combination of: (a) an S1···Cg1ii contact of 3.433 Å [symmetry code: (ii) -x+1, -y+1, -z+2; Cg1 represents the centroid of the C10–C15 benzene ring], (b) an aromatic Cg1···Cg1iii π–π stacking interaction [symmetry code: (iii) -x+2, -y, -z+2] involving the C10–C15 benzene rings, with an interplanar spacing of 3.5481 (11) Å, a ring-centroid separation of 3.7721 (17) Å and a ring-centroid offset of 1.281 Å, and (c) a C17—H17···O2iv [symmetry code: (iv) -x+1, -y, -z+2] hydrogen bond (Table 2). The contact forms a chain in the [001] direction. Furthermore, the hydrogen bond along with the contact described above generates a sheet parallel to the bc plance. Finally, the π–π stacking interaction makes the sheet packed along the a axis to result in the formation of a three-dimensional supramolecular structure.
Unlike the above crystalline state, the molecule of (I) in CDCl3 exhibits fluxionality on the NMR timescale, with only one carbonyl signal observed in the 13C NMR spectrum (Shi & Gu, 2013).