Dichloro(norbornadiene)platinum(II): a comparison with dichloro(cyclooctadiene)platinum(II)
Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270104012491/na1667sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270104012491/na1667Isup2.hkl |
CCDC reference: 245869
We have recently reported an improved synthesis of (I) (Butikofer et al., 2004). Single crystals of (I) were obtained by heating a benzene solution of (NBD)Pt(CH2Cl)2 at 373 K in a sealed NMR tube. Formation of (I) most likely resulted from thermal decomposition (via ethylene loss) of the chloromethyl species at these temperatures.
H atoms were added in calculated positions and treated as riding, with C—H distances in the range 0.97–0.98 Å and with Uiso(H) = 1.2Ueq(C). Please check added text.
Data collection: XSCANS (Bruker, 1997); cell refinement: XSCANS; data reduction: SHELXTL (Bruker, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL; software used to prepare material for publication: SHELXTL.
Fig. 1. The molecular structure of (I), showing 30% probability displacement ellipsoids. H atoms have been omitted for clarity. |
[PtCl2(C7H8)] | F(000) = 1296 |
Mr = 358.12 | Dx = 2.946 Mg m−3 |
Monoclinic, C2/c | Mo Kα radiation, λ = 0.71073 Å |
a = 12.8717 (17) Å | Cell parameters from 35 reflections |
b = 11.5173 (12) Å | θ = 4.8–12.5° |
c = 12.6441 (13) Å | µ = 17.95 mm−1 |
β = 120.507 (12)° | T = 298 K |
V = 1615.0 (3) Å3 | Rectangular prism, colorless |
Z = 8 | 0.52 × 0.12 × 0.08 mm |
Bruker P4 diffractometer | 1559 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.055 |
Graphite monochromator | θmax = 27.5°, θmin = 2.6° |
ω scans | h = −1→16 |
Absorption correction: ψ scan (SHELXL97; Sheldrick, 1997) | k = −1→14 |
Tmin = 0.080, Tmax = 0.237 | l = −16→14 |
2291 measured reflections | 3 standard reflections every 97 reflections |
1843 independent reflections | intensity decay: 1% |
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)] = 0.035 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.090 | H-atom parameters constrained |
S = 1.06 | w = 1 /[σ2(Fo2) + (0.0552P)2] where P = (Fo2 + 2Fc2)/3 |
1843 reflections | (Δ/σ)max < 0.001 |
91 parameters | Δρmax = 2.00 e Å−3 |
0 restraints | Δρmin = −2.24 e Å−3 |
[PtCl2(C7H8)] | V = 1615.0 (3) Å3 |
Mr = 358.12 | Z = 8 |
Monoclinic, C2/c | Mo Kα radiation |
a = 12.8717 (17) Å | µ = 17.95 mm−1 |
b = 11.5173 (12) Å | T = 298 K |
c = 12.6441 (13) Å | 0.52 × 0.12 × 0.08 mm |
β = 120.507 (12)° |
Bruker P4 diffractometer | 1559 reflections with I > 2σ(I) |
Absorption correction: ψ scan (SHELXL97; Sheldrick, 1997) | Rint = 0.055 |
Tmin = 0.080, Tmax = 0.237 | 3 standard reflections every 97 reflections |
2291 measured reflections | intensity decay: 1% |
1843 independent reflections |
R[F2 > 2σ(F2)] = 0.035 | 0 restraints |
wR(F2) = 0.090 | H-atom parameters constrained |
S = 1.06 | Δρmax = 2.00 e Å−3 |
1843 reflections | Δρmin = −2.24 e Å−3 |
91 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 | ||
Pt1 | 0.13972 (2) | 0.35839 (2) | 0.04013 (2) | 0.02254 (12) | |
Cl1 | 0.17622 (18) | 0.4248 (2) | −0.11005 (18) | 0.0372 (4) | |
Cl2 | 0.30434 (18) | 0.45664 (18) | 0.19149 (19) | 0.0382 (5) | |
C1 | 0.1149 (7) | 0.2400 (7) | 0.1566 (7) | 0.0314 (18) | |
H1A | 0.1797 | 0.2186 | 0.2390 | 0.038* | |
C2 | 0.0411 (8) | 0.3364 (7) | 0.1333 (8) | 0.0338 (19) | |
H2A | 0.0496 | 0.3890 | 0.1981 | 0.041* | |
C3 | −0.0808 (8) | 0.3064 (8) | 0.0211 (9) | 0.0371 (19) | |
H3A | −0.1504 | 0.3534 | 0.0064 | 0.045* | |
C4 | −0.0452 (7) | 0.3083 (8) | −0.0774 (8) | 0.0320 (17) | |
H4A | −0.0967 | 0.3411 | −0.1594 | 0.038* | |
C5 | 0.0280 (7) | 0.2123 (8) | −0.0555 (7) | 0.0311 (17) | |
H5A | 0.0327 | 0.1713 | −0.1208 | 0.037* | |
C6 | 0.0397 (8) | 0.1509 (7) | 0.0570 (9) | 0.0353 (19) | |
H6A | 0.0676 | 0.0701 | 0.0713 | 0.042* | |
C7 | −0.0878 (8) | 0.1761 (8) | 0.0369 (10) | 0.040 (2) | |
H7C | −0.1517 | 0.1390 | −0.0361 | 0.048* | |
H7A | −0.0946 | 0.1567 | 0.1078 | 0.048* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Pt1 | 0.01997 (17) | 0.02581 (18) | 0.01700 (18) | −0.00235 (11) | 0.00585 (13) | −0.00180 (11) |
Cl1 | 0.0378 (10) | 0.0506 (12) | 0.0246 (9) | −0.0057 (10) | 0.0170 (8) | −0.0008 (9) |
Cl2 | 0.0333 (10) | 0.0415 (11) | 0.0264 (9) | −0.0129 (8) | 0.0054 (8) | −0.0085 (9) |
C1 | 0.032 (4) | 0.040 (4) | 0.011 (3) | −0.004 (3) | 0.002 (3) | 0.008 (3) |
C2 | 0.043 (5) | 0.034 (4) | 0.034 (5) | −0.013 (4) | 0.027 (4) | −0.013 (4) |
C3 | 0.027 (4) | 0.037 (5) | 0.048 (5) | 0.002 (4) | 0.020 (4) | 0.006 (4) |
C4 | 0.016 (3) | 0.046 (5) | 0.022 (4) | −0.009 (3) | 0.000 (3) | −0.003 (4) |
C5 | 0.024 (4) | 0.041 (5) | 0.018 (4) | −0.007 (3) | 0.003 (3) | −0.008 (3) |
C6 | 0.038 (5) | 0.020 (4) | 0.047 (6) | −0.007 (3) | 0.021 (4) | 0.000 (3) |
C7 | 0.039 (5) | 0.038 (5) | 0.045 (6) | −0.007 (4) | 0.023 (5) | 0.002 (4) |
Pt1—C2 | 2.140 (8) | C3—C7 | 1.522 (12) |
Pt1—C5 | 2.144 (8) | C3—C4 | 1.530 (12) |
Pt1—C1 | 2.146 (7) | C3—H3A | 0.9800 |
Pt1—C4 | 2.148 (7) | C4—C5 | 1.386 (12) |
Pt1—Cl2 | 2.3056 (19) | C4—H4A | 0.9800 |
Pt1—Cl1 | 2.3058 (19) | C5—C6 | 1.525 (12) |
C1—C2 | 1.391 (12) | C5—H5A | 0.9800 |
C1—C6 | 1.529 (11) | C6—C7 | 1.555 (12) |
C1—H1A | 0.9800 | C6—H6A | 0.9800 |
C2—C3 | 1.528 (13) | C7—H7C | 0.9700 |
C2—H2A | 0.9800 | C7—H7A | 0.9700 |
C2—Pt1—C5 | 78.5 (3) | C2—C3—C4 | 99.3 (6) |
C2—Pt1—C1 | 37.9 (3) | C7—C3—H3A | 117.4 |
C5—Pt1—C1 | 66.2 (3) | C2—C3—H3A | 117.4 |
C2—Pt1—C4 | 65.8 (3) | C4—C3—H3A | 117.4 |
C5—Pt1—C4 | 37.7 (3) | C5—C4—C3 | 106.3 (7) |
C1—Pt1—C4 | 78.8 (3) | C5—C4—Pt1 | 71.0 (4) |
C2—Pt1—Cl2 | 98.8 (2) | C3—C4—Pt1 | 97.2 (5) |
C5—Pt1—Cl2 | 157.5 (2) | C5—C4—H4A | 123.0 |
C1—Pt1—Cl2 | 97.8 (2) | C3—C4—H4A | 123.0 |
C4—Pt1—Cl2 | 159.2 (2) | Pt1—C4—H4A | 123.0 |
C2—Pt1—Cl1 | 156.7 (3) | C4—C5—C6 | 107.0 (7) |
C5—Pt1—Cl1 | 98.9 (2) | C4—C5—Pt1 | 71.3 (5) |
C1—Pt1—Cl1 | 159.9 (2) | C6—C5—Pt1 | 96.8 (5) |
C4—Pt1—Cl1 | 97.9 (2) | C4—C5—H5A | 122.9 |
Cl2—Pt1—Cl1 | 92.02 (8) | C6—C5—H5A | 122.9 |
C2—C1—C6 | 106.4 (7) | Pt1—C5—H5A | 122.9 |
C2—C1—Pt1 | 70.8 (5) | C5—C6—C1 | 100.2 (6) |
C6—C1—Pt1 | 96.5 (5) | C5—C6—C7 | 99.4 (7) |
C2—C1—H1A | 123.2 | C1—C6—C7 | 100.6 (7) |
C6—C1—H1A | 123.2 | C5—C6—H6A | 117.7 |
Pt1—C1—H1A | 123.2 | C1—C6—H6A | 117.7 |
C1—C2—C3 | 106.6 (7) | C7—C6—H6A | 117.7 |
C1—C2—Pt1 | 71.3 (5) | C3—C7—C6 | 94.5 (6) |
C3—C2—Pt1 | 97.6 (5) | C3—C7—H7C | 112.8 |
C1—C2—H2A | 122.8 | C6—C7—H7C | 112.8 |
C3—C2—H2A | 122.8 | C3—C7—H7A | 112.8 |
Pt1—C2—H2A | 122.8 | C6—C7—H7A | 112.8 |
C7—C3—C2 | 101.7 (7) | H7C—C7—H7A | 110.3 |
C7—C3—C4 | 100.5 (8) |
Experimental details
Crystal data | |
Chemical formula | [PtCl2(C7H8)] |
Mr | 358.12 |
Crystal system, space group | Monoclinic, C2/c |
Temperature (K) | 298 |
a, b, c (Å) | 12.8717 (17), 11.5173 (12), 12.6441 (13) |
β (°) | 120.507 (12) |
V (Å3) | 1615.0 (3) |
Z | 8 |
Radiation type | Mo Kα |
µ (mm−1) | 17.95 |
Crystal size (mm) | 0.52 × 0.12 × 0.08 |
Data collection | |
Diffractometer | Bruker P4 diffractometer |
Absorption correction | ψ scan (SHELXL97; Sheldrick, 1997) |
Tmin, Tmax | 0.080, 0.237 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 2291, 1843, 1559 |
Rint | 0.055 |
(sin θ/λ)max (Å−1) | 0.650 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.035, 0.090, 1.06 |
No. of reflections | 1843 |
No. of parameters | 91 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 2.00, −2.24 |
Computer programs: XSCANS (Bruker, 1997), XSCANS, SHELXTL (Bruker, 1997), SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), SHELXTL.
Pt1—C2 | 2.140 (8) | Pt1—Cl2 | 2.3056 (19) |
Pt1—C5 | 2.144 (8) | Pt1—Cl1 | 2.3058 (19) |
Pt1—C1 | 2.146 (7) | C1—C2 | 1.391 (12) |
Pt1—C4 | 2.148 (7) | C4—C5 | 1.386 (12) |
C5—Pt1—C1 | 66.2 (3) | C5—Pt1—Cl1 | 98.9 (2) |
C2—Pt1—C4 | 65.8 (3) | C4—Pt1—Cl1 | 97.9 (2) |
C2—Pt1—Cl2 | 98.8 (2) | Cl2—Pt1—Cl1 | 92.02 (8) |
C1—Pt1—Cl2 | 97.8 (2) |
In platinum(II) chemistry, norbornadiene (NBD) is generally considered to be a more labile ligand than 1,5-cyclooctadiene (COD) (Appleton et al., 1986, 1989). This lability is often attributed to the smaller bite angle of the chelating NBD ligand versus COD. However, there are very few corresponding structurally characterized COD (Klein et al., 1999) and NBD (Kickelbick et al., 2002) platinum(II) complexes. We now report the crystal structure of the title compound, (NBD)PtCl2, (I), and compare it with that of (COD)PtCl2, (II) (Syed et al., 1984). \sch
The two Cl atoms and the centroids of the alkene NBD bonds form an essentially square-planar environment around the Pt atom in (I). The bite angle, as defined by the angle between the two alkene centroid positions and the Pt, is 70.3°. This is similar to what has been observed in other (NBD)PtII complexes, such as (NBD)Pt(Cl)Me (69.1°; Kickelbick et al., 2002) and (NBD)Pt(2-ethoxynapth-1-yl)2 (70.4°; Debaerdemaeker et al., 1987), but is significantly smaller than the bite angle of 87.3° found for (II), as expected. The Cl—Pt—Cl bond angle in (I) [92.02 (8)°] is slightly larger than the corresponding angle in (II) [89.78 (5)°] and this is most likely due to the different bite angles of the NBD and COD supporting ligands.
The Pt—C bond lengths in (I) do not reflect the enhanced lability of the NBD chelate. They are, in fact, significantly shorter than those found in (II): the average Pt—C bond length in (I) is 2.145 Å, versus 2.170 Å in (II). Therefore, the increased lability often observed for NBD in PtII systems cannot be attributed to a loosely bound NBD ligand, but probably results from relief of binding strain associated with the small bite angle. The Pt—Cl bond lengths in (I), as well as the C—C alkene bond lengths, are very similar to those found in (II), indicating that NBD and COD have similar donating abilities.