Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536807023835/bt2366sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S1600536807023835/bt2366Isup2.hkl |
CCDC reference: 650692
Key indicators
- Single-crystal X-ray study
- T = 173 K
- Mean (C-C) = 0.005 Å
- R factor = 0.023
- wR factor = 0.060
- Data-to-parameter ratio = 24.4
checkCIF/PLATON results
No syntax errors found
Alert level C PLAT143_ALERT_4_C su on c - Axis Small or Missing (x 100000) ..... 10 Ang. PLAT153_ALERT_1_C The su's on the Cell Axes are Equal (x 100000) 10 Ang. PLAT154_ALERT_1_C The su's on the Cell Angles are Equal (x 10000) 70 Deg. PLAT180_ALERT_3_C Check Cell Rounding: # of Values Ending with 0 = 3
Alert level G PLAT794_ALERT_5_G Check Predicted Bond Valency for Fe1 (3) 3.78
0 ALERT level A = In general: serious problem 0 ALERT level B = Potentially serious problem 4 ALERT level C = Check and explain 1 ALERT level G = General alerts; check 2 ALERT type 1 CIF construction/syntax error, inconsistent or missing data 0 ALERT type 2 Indicator that the structure model may be wrong or deficient 1 ALERT type 3 Indicator that the structure quality may be low 1 ALERT type 4 Improvement, methodology, query or suggestion 1 ALERT type 5 Informative message, check
For related literature, see: Allen (2002); Bruno et al. (2002); Canales et al. (1997); Constable et al. (2007); Crespo et al. (2000); Desiraju & Steiner (1999); Gimeno et al. (1993); Hill et al. (1989).
Crystals of compound I (Hill et al., 1989; Gimeno et al., 1993) were grown from a CH3CN solution by slow evaporation at room temperature.
All H atoms were treated as riding models, with C—H = 1.00 Å and Uiso(H) = 1.2Ueq(C).
The structure of unsolvated I has previously been reported (Crespo et al., 2000) as has the structure of I.2CH2Cl2 (Canales et al., 1997). During the course of our investigations of 2,2':6',2"-terpyridine ligands functionalized in the 4'-position with alkyl gold(I) phosphine moieties (Constable et al., 2007), we have prepared a number of gold(I) phosphine derivatives including compound I. Crystals grown from CH3CN proved to be a polymorph, Ia, (triclinic, P1) of those grown by Crespo et al. from CH2Cl2/n-heptane, Ib, (monoclinic, P21/n, refcode XEGGEV) (CSD, Version 5.2.7; Allen, 2002; Bruno et al., 2002). The molecular structure of Ia is shown in Fig. 1. In both this and Ib, the Fe atom lies on an inversion centre. Bond distances are angles are unexceptional and show little variation between polymorphs. The difference in the structures is in the orientation of the phenyl rings and the effect that this has on the molecular packing. The hydrogen bond acceptor strength of an M—Cl chlorine atom is greater than that of a CCl group, and examples of CH···ClM interactions in the solid state have been recognized for some time (Desiraju & Steiner, 1999). Fig. 2 compares the CH···Cl close contacts that exist in polymorphs Ia and Ib, and details of those in Ia are given in Table 1. In Ia, CH···Cl interactions involving H6 connect molecules into chains running parallel to the crystallographic b axis. These chains are interconnected by interactions involving H10 such that the lattice is extended in the c direction, while contacts involving H11 extend the lattice in the a direction. In addition to these non-classical hydrogen bonds, the molecular packing in Ia involves CHphenyl···πcyclopentadienyl and CHcyclopentadienyl···πphenyl interactions (Table 1). The differences between the molecular structures of Ia and Ib are relatively small, but are sufficient to cause significant differences in assembly of molecules in the crystal lattice.
For related literature, see: Allen (2002); Bruno et al. (2002); Canales et al. (1997); Constable et al. (2007); Crespo et al. (2000); Desiraju & Steiner (1999); Gimeno et al. (1993); Hill et al. (1989).
Data collection: COLLECT (Nonius, 2001); cell refinement: DENZO/SCALEPACK (Otwinowski & Minor, 1997); data reduction: DENZO/SCALEPACK; program(s) used to solve structure: SIR92 (Altomare et al., 1994); program(s) used to refine structure: CRYSTALS (Betteridge et al., 2003); molecular graphics: ORTEP-3 (Farrugia, 1997); software used to prepare material for publication: CRYSTALS.
[Au2Cl2{Fe(C17H14P)2}] | Z = 1 |
Mr = 1019.23 | F(000) = 480 |
Triclinic, P1 | Dx = 2.144 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 8.6273 (1) Å | Cell parameters from 4616 reflections |
b = 9.0401 (1) Å | θ = 1–30° |
c = 10.3715 (1) Å | µ = 10.02 mm−1 |
α = 80.9701 (7)° | T = 173 K |
β = 86.0279 (7)° | Plate, colourless |
γ = 81.6056 (7)° | 0.15 × 0.08 × 0.03 mm |
V = 789.42 (1) Å3 |
Nonius KappaCCD diffractometer | 4217 reflections with I > 2.0σ(I) |
Graphite monochromator | Rint = 0.022 |
φ & ω scans | θmax = 30.0°, θmin = 2.0° |
Absorption correction: multi-scan (DENZO/SCALEPACK; Otwinowski & Minor, 1997) | h = −11→12 |
Tmin = 0.41, Tmax = 0.74 | k = −12→12 |
9181 measured reflections | l = −14→14 |
4616 independent reflections |
Refinement on F2 | Hydrogen site location: inferred from neighbouring sites |
Least-squares matrix: full | H-atom parameters constrained |
R[F2 > 2σ(F2)] = 0.023 | Method = Modified Sheldrick (1997)
w = 1/[σ2(F2) + ( 0.04P)2 + 0.29P]
, where P = (max(Fo2,0) + 2Fc2)/3 |
wR(F2) = 0.060 | (Δ/σ)max = 0.001 |
S = 0.97 | Δρmax = 1.50 e Å−3 |
4592 reflections | Δρmin = −1.28 e Å−3 |
188 parameters | Extinction correction: Larson (1970), Equation 22 |
0 restraints | Extinction coefficient: 17.7 (19) |
Primary atom site location: structure-invariant direct methods |
[Au2Cl2{Fe(C17H14P)2}] | γ = 81.6056 (7)° |
Mr = 1019.23 | V = 789.42 (1) Å3 |
Triclinic, P1 | Z = 1 |
a = 8.6273 (1) Å | Mo Kα radiation |
b = 9.0401 (1) Å | µ = 10.02 mm−1 |
c = 10.3715 (1) Å | T = 173 K |
α = 80.9701 (7)° | 0.15 × 0.08 × 0.03 mm |
β = 86.0279 (7)° |
Nonius KappaCCD diffractometer | 4616 independent reflections |
Absorption correction: multi-scan (DENZO/SCALEPACK; Otwinowski & Minor, 1997) | 4217 reflections with I > 2.0σ(I) |
Tmin = 0.41, Tmax = 0.74 | Rint = 0.022 |
9181 measured reflections |
R[F2 > 2σ(F2)] = 0.023 | 0 restraints |
wR(F2) = 0.060 | H-atom parameters constrained |
S = 0.97 | Δρmax = 1.50 e Å−3 |
4592 reflections | Δρmin = −1.28 e Å−3 |
188 parameters |
x | y | z | Uiso*/Ueq | ||
Au1 | 0.676196 (12) | 0.288418 (11) | 0.887313 (10) | 0.0239 | |
Fe1 | 0.5000 | 0.5000 | 0.5000 | 0.0196 | |
P1 | 0.58777 (9) | 0.18016 (8) | 0.73340 (7) | 0.0200 | |
Cl1 | 0.77243 (11) | 0.39466 (9) | 1.04541 (8) | 0.0322 | |
C1 | 0.5978 (3) | 0.2875 (3) | 0.5729 (3) | 0.0217 | |
C2 | 0.7182 (3) | 0.3798 (3) | 0.5271 (3) | 0.0270 | |
C3 | 0.6988 (4) | 0.4300 (4) | 0.3915 (3) | 0.0330 | |
C4 | 0.5690 (4) | 0.3719 (4) | 0.3530 (3) | 0.0317 | |
C5 | 0.5056 (4) | 0.2828 (3) | 0.4649 (3) | 0.0257 | |
C6 | 0.7023 (3) | −0.0012 (3) | 0.7130 (3) | 0.0230 | |
C7 | 0.7062 (4) | −0.1191 (4) | 0.8177 (3) | 0.0379 | |
C8 | 0.7948 (5) | −0.2580 (4) | 0.8063 (4) | 0.0435 | |
C9 | 0.8807 (4) | −0.2802 (4) | 0.6918 (4) | 0.0387 | |
C10 | 0.8771 (4) | −0.1646 (4) | 0.5876 (4) | 0.0373 | |
C11 | 0.7883 (4) | −0.0242 (3) | 0.5984 (3) | 0.0277 | |
C12 | 0.3878 (3) | 0.1418 (3) | 0.7685 (3) | 0.0214 | |
C13 | 0.2850 (4) | 0.2409 (4) | 0.8355 (3) | 0.0281 | |
C14 | 0.1308 (4) | 0.2151 (4) | 0.8643 (4) | 0.0366 | |
C15 | 0.0793 (4) | 0.0893 (5) | 0.8311 (4) | 0.0396 | |
C16 | 0.1833 (4) | −0.0119 (4) | 0.7659 (4) | 0.0380 | |
C17 | 0.3355 (4) | 0.0154 (4) | 0.7331 (3) | 0.0324 | |
H1 | 0.8008 | 0.4037 | 0.5807 | 0.0323* | |
H2 | 0.7659 | 0.4961 | 0.3329 | 0.0374* | |
H3 | 0.5282 | 0.3898 | 0.2631 | 0.0375* | |
H4 | 0.4134 | 0.2269 | 0.4672 | 0.0307* | |
H5 | 0.6443 | −0.1032 | 0.9008 | 0.0445* | |
H6 | 0.7974 | −0.3419 | 0.8818 | 0.0507* | |
H7 | 0.9440 | −0.3805 | 0.6840 | 0.0466* | |
H8 | 0.9394 | −0.1805 | 0.5047 | 0.0444* | |
H9 | 0.7862 | 0.0598 | 0.5230 | 0.0341* | |
H10 | 0.3232 | 0.3299 | 0.8631 | 0.0347* | |
H11 | 0.0564 | 0.2879 | 0.9097 | 0.0446* | |
H12 | −0.0314 | 0.0699 | 0.8530 | 0.0481* | |
H13 | 0.1466 | −0.1040 | 0.7429 | 0.0483* | |
H14 | 0.4083 | −0.0558 | 0.6848 | 0.0409* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Au1 | 0.02774 (8) | 0.02168 (7) | 0.02296 (8) | −0.00291 (4) | −0.00047 (4) | −0.00619 (4) |
Fe1 | 0.0205 (3) | 0.0160 (2) | 0.0210 (3) | 0.0003 (2) | 0.0025 (2) | −0.0029 (2) |
P1 | 0.0228 (3) | 0.0166 (3) | 0.0203 (3) | −0.0005 (3) | 0.0000 (3) | −0.0041 (3) |
Cl1 | 0.0438 (4) | 0.0305 (4) | 0.0254 (4) | −0.0080 (3) | −0.0015 (3) | −0.0108 (3) |
C1 | 0.0243 (13) | 0.0166 (12) | 0.0226 (13) | 0.0014 (10) | 0.0014 (10) | −0.0026 (10) |
C2 | 0.0174 (12) | 0.0240 (14) | 0.0363 (17) | 0.0019 (10) | 0.0026 (11) | 0.0000 (12) |
C3 | 0.0328 (16) | 0.0239 (14) | 0.0358 (17) | 0.0050 (12) | 0.0147 (14) | 0.0005 (12) |
C4 | 0.0422 (18) | 0.0247 (15) | 0.0245 (15) | 0.0070 (13) | 0.0050 (13) | −0.0060 (12) |
C5 | 0.0335 (15) | 0.0161 (12) | 0.0271 (15) | 0.0015 (11) | −0.0009 (12) | −0.0066 (11) |
C6 | 0.0238 (13) | 0.0168 (12) | 0.0276 (14) | 0.0007 (10) | −0.0033 (11) | −0.0035 (10) |
C7 | 0.052 (2) | 0.0260 (16) | 0.0307 (17) | 0.0057 (15) | −0.0018 (15) | 0.0016 (13) |
C8 | 0.056 (2) | 0.0263 (17) | 0.044 (2) | 0.0059 (16) | −0.0097 (18) | 0.0017 (15) |
C9 | 0.0330 (17) | 0.0246 (16) | 0.058 (2) | 0.0070 (13) | −0.0125 (16) | −0.0112 (15) |
C10 | 0.0261 (15) | 0.0291 (16) | 0.057 (2) | 0.0010 (13) | 0.0061 (15) | −0.0164 (16) |
C11 | 0.0277 (14) | 0.0229 (14) | 0.0318 (16) | −0.0015 (11) | 0.0027 (12) | −0.0052 (12) |
C12 | 0.0221 (12) | 0.0210 (12) | 0.0207 (13) | −0.0018 (10) | −0.0005 (10) | −0.0031 (10) |
C13 | 0.0267 (14) | 0.0277 (15) | 0.0305 (16) | −0.0014 (12) | 0.0007 (12) | −0.0088 (12) |
C14 | 0.0269 (15) | 0.044 (2) | 0.0368 (18) | 0.0015 (14) | 0.0048 (13) | −0.0095 (15) |
C15 | 0.0281 (16) | 0.050 (2) | 0.040 (2) | −0.0112 (15) | −0.0002 (14) | −0.0006 (16) |
C16 | 0.0408 (19) | 0.0343 (18) | 0.042 (2) | −0.0169 (15) | −0.0013 (15) | −0.0038 (15) |
C17 | 0.0346 (17) | 0.0267 (15) | 0.0372 (18) | −0.0059 (13) | 0.0021 (14) | −0.0093 (13) |
Au1—P1 | 2.2283 (7) | C5—H4 | 1.000 |
Au1—Cl1 | 2.2838 (8) | C6—C7 | 1.395 (4) |
Fe1—C3i | 2.061 (3) | C6—C11 | 1.385 (4) |
Fe1—C4i | 2.061 (3) | C7—C8 | 1.389 (5) |
Fe1—C5i | 2.046 (3) | C7—H5 | 1.000 |
Fe1—C2i | 2.046 (3) | C8—C9 | 1.382 (6) |
Fe1—C1i | 2.033 (3) | C8—H6 | 1.000 |
Fe1—C1 | 2.033 (3) | C9—C10 | 1.379 (5) |
Fe1—C2 | 2.046 (3) | C9—H7 | 1.000 |
Fe1—C3 | 2.061 (3) | C10—C11 | 1.399 (4) |
Fe1—C4 | 2.061 (3) | C10—H8 | 1.000 |
Fe1—C5 | 2.046 (3) | C11—H9 | 1.000 |
P1—C1 | 1.793 (3) | C12—C13 | 1.397 (4) |
P1—C6 | 1.821 (3) | C12—C17 | 1.396 (4) |
P1—C12 | 1.811 (3) | C13—C14 | 1.389 (5) |
C1—C2 | 1.436 (4) | C13—H10 | 1.000 |
C1—C5 | 1.428 (4) | C14—C15 | 1.379 (5) |
C2—C3 | 1.422 (5) | C14—H11 | 1.000 |
C2—H1 | 1.000 | C15—C16 | 1.403 (5) |
C3—C4 | 1.411 (5) | C15—H12 | 1.000 |
C3—H2 | 1.000 | C16—C17 | 1.381 (5) |
C4—C5 | 1.429 (4) | C16—H13 | 1.000 |
C4—H3 | 1.000 | C17—H14 | 1.000 |
P1—Au1—Cl1 | 178.51 (2) | C1—C2—C3 | 107.3 (3) |
C3i—Fe1—C4i | 40.03 (14) | Fe1—C2—C3 | 70.32 (17) |
C3i—Fe1—C5i | 68.05 (13) | C1—C2—H1 | 126.2 |
C4i—Fe1—C5i | 40.72 (12) | Fe1—C2—H1 | 126.2 |
C3i—Fe1—C2i | 40.51 (13) | C3—C2—H1 | 126.4 |
C4i—Fe1—C2i | 68.30 (14) | C2—C3—Fe1 | 69.16 (16) |
C5i—Fe1—C2i | 68.93 (13) | C2—C3—C4 | 108.9 (3) |
C3i—Fe1—C1i | 68.42 (12) | Fe1—C3—C4 | 69.99 (17) |
C4i—Fe1—C1i | 68.61 (12) | C2—C3—H2 | 125.6 |
C5i—Fe1—C1i | 40.98 (12) | Fe1—C3—H2 | 126.7 |
C2i—Fe1—C1i | 41.22 (11) | C4—C3—H2 | 125.4 |
C3i—Fe1—C1 | 111.58 (12) | C3—C4—Fe1 | 69.99 (18) |
C4i—Fe1—C1 | 111.39 (12) | C3—C4—C5 | 108.1 (3) |
C5i—Fe1—C1 | 139.02 (12) | Fe1—C4—C5 | 69.07 (17) |
C2i—Fe1—C1 | 138.78 (11) | C3—C4—H3 | 126.1 |
C1i—Fe1—C1 | 179.994 | Fe1—C4—H3 | 126.6 |
C3i—Fe1—C2 | 139.49 (13) | C5—C4—H3 | 125.9 |
C4i—Fe1—C2 | 111.70 (14) | C4—C5—C1 | 107.8 (3) |
C5i—Fe1—C2 | 111.07 (13) | C4—C5—Fe1 | 70.21 (17) |
C2i—Fe1—C2 | 179.994 | C1—C5—Fe1 | 69.04 (16) |
C1i—Fe1—C2 | 138.78 (11) | C4—C5—H4 | 126.2 |
C3i—Fe1—C3 | 179.994 | C1—C5—H4 | 126.1 |
C4i—Fe1—C3 | 139.97 (14) | Fe1—C5—H4 | 126.3 |
C5i—Fe1—C3 | 111.95 (13) | P1—C6—C7 | 118.7 (2) |
C2i—Fe1—C3 | 139.49 (13) | P1—C6—C11 | 122.1 (2) |
C1i—Fe1—C3 | 111.58 (12) | C7—C6—C11 | 119.2 (3) |
C3i—Fe1—C4 | 139.97 (14) | C6—C7—C8 | 120.1 (3) |
C4i—Fe1—C4 | 179.994 | C6—C7—H5 | 119.6 |
C5i—Fe1—C4 | 139.28 (12) | C8—C7—H5 | 120.2 |
C2i—Fe1—C4 | 111.70 (14) | C7—C8—C9 | 120.3 (3) |
C1i—Fe1—C4 | 111.39 (12) | C7—C8—H6 | 119.8 |
C3i—Fe1—C5 | 111.95 (13) | C9—C8—H6 | 119.9 |
C4i—Fe1—C5 | 139.28 (12) | C8—C9—C10 | 120.0 (3) |
C5i—Fe1—C5 | 179.994 | C8—C9—H7 | 120.0 |
C2i—Fe1—C5 | 111.07 (13) | C10—C9—H7 | 120.1 |
C1i—Fe1—C5 | 139.02 (12) | C9—C10—C11 | 120.0 (3) |
C1—Fe1—C2 | 41.22 (11) | C9—C10—H8 | 120.0 |
C1—Fe1—C3 | 68.42 (12) | C11—C10—H8 | 120.0 |
C2—Fe1—C3 | 40.51 (13) | C10—C11—C6 | 120.3 (3) |
C1—Fe1—C4 | 68.61 (12) | C10—C11—H9 | 120.0 |
C2—Fe1—C4 | 68.30 (14) | C6—C11—H9 | 119.7 |
C3—Fe1—C4 | 40.03 (14) | P1—C12—C13 | 118.3 (2) |
C1—Fe1—C5 | 40.98 (12) | P1—C12—C17 | 122.0 (2) |
C2—Fe1—C5 | 68.93 (13) | C13—C12—C17 | 119.7 (3) |
C3—Fe1—C5 | 68.05 (13) | C12—C13—C14 | 119.9 (3) |
C4—Fe1—C5 | 40.72 (12) | C12—C13—H10 | 119.8 |
Au1—P1—C1 | 113.78 (10) | C14—C13—H10 | 120.3 |
Au1—P1—C6 | 112.85 (10) | C13—C14—C15 | 120.5 (3) |
C1—P1—C6 | 103.33 (13) | C13—C14—H11 | 119.9 |
Au1—P1—C12 | 112.80 (10) | C15—C14—H11 | 119.6 |
C1—P1—C12 | 107.81 (13) | C14—C15—C16 | 119.5 (3) |
C6—P1—C12 | 105.49 (13) | C14—C15—H12 | 120.5 |
P1—C1—Fe1 | 131.79 (15) | C16—C15—H12 | 120.0 |
P1—C1—C2 | 123.9 (2) | C15—C16—C17 | 120.4 (3) |
Fe1—C1—C2 | 69.86 (16) | C15—C16—H13 | 119.6 |
P1—C1—C5 | 127.7 (2) | C17—C16—H13 | 120.0 |
Fe1—C1—C5 | 69.98 (15) | C12—C17—C16 | 119.9 (3) |
C2—C1—C5 | 107.9 (3) | C12—C17—H14 | 120.1 |
C1—C2—Fe1 | 68.93 (15) | C16—C17—H14 | 120.0 |
Symmetry code: (i) −x+1, −y+1, −z+1. |
Experimental details
Crystal data | |
Chemical formula | [Au2Cl2{Fe(C17H14P)2}] |
Mr | 1019.23 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 173 |
a, b, c (Å) | 8.6273 (1), 9.0401 (1), 10.3715 (1) |
α, β, γ (°) | 80.9701 (7), 86.0279 (7), 81.6056 (7) |
V (Å3) | 789.42 (1) |
Z | 1 |
Radiation type | Mo Kα |
µ (mm−1) | 10.02 |
Crystal size (mm) | 0.15 × 0.08 × 0.03 |
Data collection | |
Diffractometer | Nonius KappaCCD |
Absorption correction | Multi-scan (DENZO/SCALEPACK; Otwinowski & Minor, 1997) |
Tmin, Tmax | 0.41, 0.74 |
No. of measured, independent and observed [I > 2.0σ(I)] reflections | 9181, 4616, 4217 |
Rint | 0.022 |
(sin θ/λ)max (Å−1) | 0.704 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.023, 0.060, 0.97 |
No. of reflections | 4592 |
No. of parameters | 188 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 1.50, −1.28 |
Computer programs: COLLECT (Nonius, 2001), DENZO/SCALEPACK (Otwinowski & Minor, 1997), DENZO/SCALEPACK, SIR92 (Altomare et al., 1994), CRYSTALS (Betteridge et al., 2003), ORTEP-3 (Farrugia, 1997), CRYSTALS.
Au1—P1 | 2.2283 (7) | P1—C6 | 1.821 (3) |
Au1—Cl1 | 2.2838 (8) | P1—C12 | 1.811 (3) |
P1—C1 | 1.793 (3) | ||
P1—Au1—Cl1 | 178.51 (2) | Au1—P1—C12 | 112.80 (10) |
Au1—P1—C1 | 113.78 (10) | C1—P1—C12 | 107.81 (13) |
Au1—P1—C6 | 112.85 (10) | C6—P1—C12 | 105.49 (13) |
C1—P1—C6 | 103.33 (13) |
D—H···A | H···A | D···A | D-H···A | Symmetry code |
C8—H6···Cl1i | 2.73 | 3.703 (4) | 166 | x, -1 + y, z |
C13–H10···Cl1ii | 2.80 | 3.653 (4) | 144 | 1-x, 1-y, 2-z |
C14—H11···Cl1iii | 2.86 | 3.796 (4) | 156 | -1 + x, y, z |
Cyclopentadienyl(centroid)···H14—C17iv | 3.31 | 3.71 | 137 | 1-x,-y,1-z |
Phenyl(C6–C11)(centroid)···H4—C5iv | 2.84 | 3.67 | 141 | 1-x, -y, 1-z |
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The structure of unsolvated I has previously been reported (Crespo et al., 2000) as has the structure of I.2CH2Cl2 (Canales et al., 1997). During the course of our investigations of 2,2':6',2"-terpyridine ligands functionalized in the 4'-position with alkyl gold(I) phosphine moieties (Constable et al., 2007), we have prepared a number of gold(I) phosphine derivatives including compound I. Crystals grown from CH3CN proved to be a polymorph, Ia, (triclinic, P1) of those grown by Crespo et al. from CH2Cl2/n-heptane, Ib, (monoclinic, P21/n, refcode XEGGEV) (CSD, Version 5.2.7; Allen, 2002; Bruno et al., 2002). The molecular structure of Ia is shown in Fig. 1. In both this and Ib, the Fe atom lies on an inversion centre. Bond distances are angles are unexceptional and show little variation between polymorphs. The difference in the structures is in the orientation of the phenyl rings and the effect that this has on the molecular packing. The hydrogen bond acceptor strength of an M—Cl chlorine atom is greater than that of a CCl group, and examples of CH···ClM interactions in the solid state have been recognized for some time (Desiraju & Steiner, 1999). Fig. 2 compares the CH···Cl close contacts that exist in polymorphs Ia and Ib, and details of those in Ia are given in Table 1. In Ia, CH···Cl interactions involving H6 connect molecules into chains running parallel to the crystallographic b axis. These chains are interconnected by interactions involving H10 such that the lattice is extended in the c direction, while contacts involving H11 extend the lattice in the a direction. In addition to these non-classical hydrogen bonds, the molecular packing in Ia involves CHphenyl···πcyclopentadienyl and CHcyclopentadienyl···πphenyl interactions (Table 1). The differences between the molecular structures of Ia and Ib are relatively small, but are sufficient to cause significant differences in assembly of molecules in the crystal lattice.