Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270101020182/ta1357sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270101020182/ta1357Isup2.hkl |
CCDC reference: 181996
Palladium acetate (0.5 g, 2.23 mmol) was dissolved in glacial acetic acid (40 ml) and then charged with compound (I) (0.71 ml, 2.23 mmol), and the mixture was refluxed for 0.5 h. To this was added LiBr (0.5 g, 12.2 mmol) and the reaction was stirred at room temperature for 1 h. The solvent was removed and the residue extracted with CH2Cl2 and passed through silica gel (7 cm), which was washed with a copious amount of CH2Cl2. The solvent was removed in vacuo from the combined CH2Cl2 washings to leave an orange residue, which was recrystallized from CH2Cl2-hexane (?:? v/v) at 123 K to give an orange-yellow solid, (I) (0.83 g, 94%). Analysis calculated for [PdBr{C6H3(CH2SiPr)2-2,6}]: C 38.23, H 4.81%; found: C 38.5, H 4.6%. 1H NMR (CDCl3, d, p.p.m.): 6.97 (s, 3H, C6H3), 4.20 (s, 4H, CH2), 3.64 (q, 2H, JHH = 6.8 Hz, iPr), 1.58 (d, 12H, JHH = 6.8 Hz, iPr).
Although all H atoms could be located in the difference Fourier map, they were placed in idealized positions and refined as riding atoms, with C—H = 0.95–1.00 Å and Uiso(H) = 1.2 or 1.5 times Ueq(C). Are these the correct constraints? Torsion angles involving methyl H atoms were refined. Please provide these in CIF-format for addition to the archived CIF.
Data collection: COLLECT (Nonius, 2001); cell refinement: SCALEPACK (Otwinowski & Minor, 1997); data reduction: SCALEPACK; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997); software used to prepare material for publication: PLATON (Spek, 1997).
Fig. 1. A view of the molecule of (I) with the atomic numbering scheme. Displacement ellipsoids are drawn at the 50% probability level and H atoms are shown as small spheres of arbitrary radii. |
[PdBr(C14H21S2)] | F(000) = 872 |
Mr = 439.77 | Dx = 1.855 Mg m−3 |
Monoclinic, P21/c | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ybc | Cell parameters from 3396 reflections |
a = 8.5591 (2) Å | θ = 2.2–27.5° |
b = 10.6777 (2) Å | µ = 3.96 mm−1 |
c = 17.6816 (4) Å | T = 173 K |
β = 103.042 (1)° | Rectangular block, light yellow |
V = 1574.3 (1) Å3 | 0.30 × 0.26 × 0.18 mm |
Z = 4 |
Nonius KappaCCD area-detector diffractometer | 3557 independent reflections |
Radiation source: fine-focus sealed tube | 3143 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.023 |
ϕ and ω scans with θ offsets | θmax = 27.5°, θmin = 2.2° |
Absorption correction: empirical (using intensity measurements) (SCALEPACK; Otwinowski & Minor, 1997) | h = −11→11 |
Tmin = 0.350, Tmax = 0.490 | k = −13→13 |
14692 measured reflections | l = −22→22 |
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.024 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.052 | w = 1/[σ2(Fo2) + (0.0158P)2 + 1.0617P] where P = (Fo2 + 2Fc2)/3 |
S = 1.08 | (Δ/σ)max = 0.001 |
3557 reflections | Δρmax = 1.07 e Å−3 |
168 parameters | Δρmin = −0.60 e Å−3 |
0 restraints | Extinction correction: SHELXL97 (Sheldrick, 1997), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
Primary atom site location: structure-invariant direct methods | Extinction coefficient: 0.00217 (17) |
[PdBr(C14H21S2)] | V = 1574.3 (1) Å3 |
Mr = 439.77 | Z = 4 |
Monoclinic, P21/c | Mo Kα radiation |
a = 8.5591 (2) Å | µ = 3.96 mm−1 |
b = 10.6777 (2) Å | T = 173 K |
c = 17.6816 (4) Å | 0.30 × 0.26 × 0.18 mm |
β = 103.042 (1)° |
Nonius KappaCCD area-detector diffractometer | 3557 independent reflections |
Absorption correction: empirical (using intensity measurements) (SCALEPACK; Otwinowski & Minor, 1997) | 3143 reflections with I > 2σ(I) |
Tmin = 0.350, Tmax = 0.490 | Rint = 0.023 |
14692 measured reflections |
R[F2 > 2σ(F2)] = 0.024 | 0 restraints |
wR(F2) = 0.052 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.08 | Δρmax = 1.07 e Å−3 |
3557 reflections | Δρmin = −0.60 e Å−3 |
168 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. |
x | y | z | Uiso*/Ueq | ||
Pd | 0.411298 (19) | 0.251864 (15) | 0.129904 (10) | 0.01833 (7) | |
Br | 0.20572 (3) | 0.33613 (2) | 0.201056 (15) | 0.02724 (8) | |
S2 | 0.62898 (7) | 0.27911 (5) | 0.23289 (3) | 0.02001 (13) | |
S1 | 0.22741 (7) | 0.21627 (6) | 0.01587 (4) | 0.02271 (13) | |
C6 | 0.7309 (3) | 0.1691 (2) | 0.11323 (14) | 0.0194 (5) | |
C8 | 0.7733 (3) | 0.1792 (2) | 0.20030 (13) | 0.0221 (5) | |
H8A | 0.8823 | 0.2148 | 0.2176 | 0.026* | |
H8B | 0.7730 | 0.0948 | 0.2235 | 0.026* | |
C12 | 0.7099 (3) | 0.4330 (2) | 0.21583 (14) | 0.0231 (5) | |
H12 | 0.7456 | 0.4302 | 0.1658 | 0.028* | |
C1 | 0.5709 (3) | 0.1892 (2) | 0.07326 (14) | 0.0204 (5) | |
C10 | 0.0347 (3) | 0.3577 (3) | −0.09938 (16) | 0.0350 (6) | |
H10A | −0.0171 | 0.4384 | −0.1152 | 0.052* | |
H10B | −0.0475 | 0.2935 | −0.1003 | 0.052* | |
H10C | 0.1017 | 0.3342 | −0.1353 | 0.052* | |
C7 | 0.3575 (3) | 0.1835 (3) | −0.05069 (15) | 0.0295 (6) | |
H7B | 0.3215 | 0.1058 | −0.0800 | 0.035* | |
H7A | 0.3501 | 0.2530 | −0.0884 | 0.035* | |
C2 | 0.5282 (3) | 0.1687 (2) | −0.00683 (14) | 0.0210 (5) | |
C14 | 0.8539 (3) | 0.4641 (2) | 0.28091 (15) | 0.0300 (6) | |
H14A | 0.8991 | 0.5448 | 0.2702 | 0.045* | |
H14B | 0.9353 | 0.3986 | 0.2843 | 0.045* | |
H14C | 0.8200 | 0.4691 | 0.3302 | 0.045* | |
C13 | 0.5790 (3) | 0.5306 (2) | 0.20912 (16) | 0.0333 (6) | |
H13A | 0.5371 | 0.5298 | 0.2563 | 0.050* | |
H13B | 0.4922 | 0.5116 | 0.1641 | 0.050* | |
H13C | 0.6231 | 0.6136 | 0.2026 | 0.050* | |
C9 | 0.1392 (3) | 0.3688 (2) | −0.01728 (15) | 0.0283 (5) | |
H9 | 0.0659 | 0.3912 | 0.0174 | 0.034* | |
C11 | 0.2621 (4) | 0.4731 (3) | −0.00953 (17) | 0.0409 (7) | |
H11A | 0.3421 | 0.4516 | −0.0393 | 0.061* | |
H11B | 0.3153 | 0.4838 | 0.0453 | 0.061* | |
H11C | 0.2084 | 0.5513 | −0.0296 | 0.061* | |
C5 | 0.8458 (3) | 0.1358 (2) | 0.07241 (14) | 0.0261 (5) | |
H5 | 0.9545 | 0.1261 | 0.0992 | 0.031* | |
C4 | 0.8026 (3) | 0.1167 (2) | −0.00704 (15) | 0.0290 (6) | |
H4 | 0.8816 | 0.0938 | −0.0346 | 0.035* | |
C3 | 0.6440 (3) | 0.1310 (2) | −0.04649 (14) | 0.0262 (5) | |
H3 | 0.6141 | 0.1151 | −0.1007 | 0.031* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Pd | 0.01639 (10) | 0.02108 (10) | 0.01757 (11) | 0.00138 (6) | 0.00393 (7) | −0.00024 (7) |
Br | 0.02441 (13) | 0.02933 (14) | 0.03057 (15) | 0.00438 (9) | 0.01167 (10) | −0.00072 (11) |
S2 | 0.0200 (3) | 0.0226 (3) | 0.0172 (3) | −0.0008 (2) | 0.0037 (2) | −0.0008 (2) |
S1 | 0.0174 (3) | 0.0282 (3) | 0.0216 (3) | 0.0011 (2) | 0.0023 (2) | 0.0000 (2) |
C6 | 0.0204 (11) | 0.0171 (10) | 0.0206 (12) | 0.0004 (8) | 0.0040 (9) | 0.0000 (9) |
C8 | 0.0209 (11) | 0.0234 (12) | 0.0206 (12) | 0.0039 (9) | 0.0021 (9) | 0.0005 (10) |
C12 | 0.0269 (12) | 0.0229 (12) | 0.0206 (13) | −0.0043 (9) | 0.0074 (10) | −0.0011 (10) |
C1 | 0.0208 (11) | 0.0190 (11) | 0.0214 (12) | −0.0018 (9) | 0.0048 (9) | −0.0003 (10) |
C10 | 0.0312 (14) | 0.0388 (15) | 0.0305 (15) | 0.0071 (11) | −0.0025 (11) | 0.0049 (12) |
C7 | 0.0220 (12) | 0.0436 (15) | 0.0217 (13) | 0.0039 (11) | 0.0022 (10) | −0.0058 (12) |
C2 | 0.0193 (11) | 0.0222 (11) | 0.0212 (12) | 0.0001 (9) | 0.0040 (9) | −0.0002 (10) |
C14 | 0.0268 (13) | 0.0325 (14) | 0.0301 (15) | −0.0073 (10) | 0.0049 (11) | −0.0030 (12) |
C13 | 0.0350 (14) | 0.0228 (12) | 0.0390 (16) | 0.0007 (11) | 0.0018 (12) | −0.0025 (12) |
C9 | 0.0269 (12) | 0.0304 (13) | 0.0262 (14) | 0.0063 (10) | 0.0030 (10) | 0.0025 (11) |
C11 | 0.0513 (18) | 0.0349 (15) | 0.0303 (16) | −0.0088 (13) | −0.0037 (13) | 0.0058 (13) |
C5 | 0.0192 (11) | 0.0298 (13) | 0.0282 (14) | 0.0030 (9) | 0.0031 (10) | −0.0017 (11) |
C4 | 0.0238 (12) | 0.0363 (14) | 0.0294 (14) | 0.0046 (11) | 0.0115 (10) | −0.0014 (12) |
C3 | 0.0275 (12) | 0.0333 (13) | 0.0183 (12) | 0.0003 (10) | 0.0061 (10) | −0.0020 (11) |
Pd—C1 | 1.984 (2) | C7—C2 | 1.500 (3) |
Pd—S1 | 2.2924 (6) | C7—H7B | 0.9900 |
Pd—S2 | 2.3110 (6) | C7—H7A | 0.9900 |
Pd—Br | 2.5471 (3) | C2—C3 | 1.396 (3) |
S2—C8 | 1.821 (2) | C14—H14A | 0.9800 |
S2—C12 | 1.835 (2) | C14—H14B | 0.9800 |
S1—C7 | 1.827 (2) | C14—H14C | 0.9800 |
S1—C9 | 1.834 (2) | C13—H13A | 0.9800 |
C6—C5 | 1.391 (3) | C13—H13B | 0.9800 |
C6—C1 | 1.409 (3) | C13—H13C | 0.9800 |
C6—C8 | 1.504 (3) | C9—C11 | 1.517 (4) |
C8—H8A | 0.9900 | C9—H9 | 1.0000 |
C8—H8B | 0.9900 | C11—H11A | 0.9800 |
C12—C13 | 1.515 (3) | C11—H11B | 0.9800 |
C12—C14 | 1.521 (3) | C11—H11C | 0.9800 |
C12—H12 | 1.0000 | C5—C4 | 1.385 (3) |
C1—C2 | 1.397 (3) | C5—H5 | 0.9500 |
C10—C9 | 1.528 (3) | C4—C3 | 1.387 (3) |
C10—H10A | 0.9800 | C4—H4 | 0.9500 |
C10—H10B | 0.9800 | C3—H3 | 0.9500 |
C10—H10C | 0.9800 | ||
C1—Pd—S1 | 85.08 (7) | C2—C7—H7A | 109.5 |
C1—Pd—S2 | 85.17 (7) | S1—C7—H7A | 109.5 |
S1—Pd—S2 | 170.19 (2) | H7B—C7—H7A | 108.1 |
C1—Pd—Br | 178.91 (7) | C3—C2—C1 | 120.1 (2) |
S1—Pd—Br | 94.549 (17) | C3—C2—C7 | 119.3 (2) |
S2—Pd—Br | 95.180 (16) | C1—C2—C7 | 120.6 (2) |
C8—S2—C12 | 99.47 (11) | C12—C14—H14A | 109.5 |
C8—S2—Pd | 99.25 (8) | C12—C14—H14B | 109.5 |
C12—S2—Pd | 104.50 (8) | H14A—C14—H14B | 109.5 |
C7—S1—C9 | 103.34 (12) | C12—C14—H14C | 109.5 |
C7—S1—Pd | 101.59 (8) | H14A—C14—H14C | 109.5 |
C9—S1—Pd | 106.57 (8) | H14B—C14—H14C | 109.5 |
C5—C6—C1 | 120.0 (2) | C12—C13—H13A | 109.5 |
C5—C6—C8 | 120.9 (2) | C12—C13—H13B | 109.5 |
C1—C6—C8 | 119.0 (2) | H13A—C13—H13B | 109.5 |
C6—C8—S2 | 109.99 (15) | C12—C13—H13C | 109.5 |
C6—C8—H8A | 109.7 | H13A—C13—H13C | 109.5 |
S2—C8—H8A | 109.7 | H13B—C13—H13C | 109.5 |
C6—C8—H8B | 109.7 | C11—C9—C10 | 112.8 (2) |
S2—C8—H8B | 109.7 | C11—C9—S1 | 113.32 (18) |
H8A—C8—H8B | 108.2 | C10—C9—S1 | 110.21 (18) |
C13—C12—C14 | 111.6 (2) | C11—C9—H9 | 106.7 |
C13—C12—S2 | 109.21 (16) | C10—C9—H9 | 106.7 |
C14—C12—S2 | 110.04 (17) | S1—C9—H9 | 106.7 |
C13—C12—H12 | 108.7 | C9—C11—H11A | 109.5 |
C14—C12—H12 | 108.7 | C9—C11—H11B | 109.5 |
S2—C12—H12 | 108.7 | H11A—C11—H11B | 109.5 |
C2—C1—C6 | 119.1 (2) | C9—C11—H11C | 109.5 |
C2—C1—Pd | 120.80 (16) | H11A—C11—H11C | 109.5 |
C6—C1—Pd | 120.02 (17) | H11B—C11—H11C | 109.5 |
C9—C10—H10A | 109.5 | C4—C5—C6 | 120.4 (2) |
C9—C10—H10B | 109.5 | C4—C5—H5 | 119.8 |
H10A—C10—H10B | 109.5 | C6—C5—H5 | 119.8 |
C9—C10—H10C | 109.5 | C5—C4—C3 | 120.1 (2) |
H10A—C10—H10C | 109.5 | C5—C4—H4 | 120.0 |
H10B—C10—H10C | 109.5 | C3—C4—H4 | 120.0 |
C2—C7—S1 | 110.57 (17) | C4—C3—C2 | 120.3 (2) |
C2—C7—H7B | 109.5 | C4—C3—H3 | 119.9 |
S1—C7—H7B | 109.5 | C2—C3—H3 | 119.9 |
C1—Pd—S2—C8 | −17.61 (10) | S2—Pd—C1—C2 | −169.34 (18) |
Br—Pd—S2—C8 | 163.42 (8) | S1—Pd—C1—C6 | −172.78 (18) |
C1—Pd—S2—C12 | 84.76 (10) | S2—Pd—C1—C6 | 8.30 (17) |
Br—Pd—S2—C12 | −94.21 (8) | C9—S1—C7—C2 | 120.36 (18) |
C1—Pd—S1—C7 | −9.81 (11) | Pd—S1—C7—C2 | 10.00 (19) |
Br—Pd—S1—C7 | 169.17 (9) | C6—C1—C2—C3 | −1.1 (3) |
C1—Pd—S1—C9 | −117.67 (11) | Pd—C1—C2—C3 | 176.56 (18) |
Br—Pd—S1—C9 | 61.31 (9) | C6—C1—C2—C7 | 177.2 (2) |
C5—C6—C8—S2 | 158.03 (18) | Pd—C1—C2—C7 | −5.1 (3) |
C1—C6—C8—S2 | −24.4 (3) | S1—C7—C2—C3 | 173.68 (19) |
C12—S2—C8—C6 | −80.86 (17) | S1—C7—C2—C1 | −4.7 (3) |
Pd—S2—C8—C6 | 25.66 (16) | C7—S1—C9—C11 | −63.1 (2) |
C8—S2—C12—C13 | 158.45 (17) | Pd—S1—C9—C11 | 43.5 (2) |
Pd—S2—C12—C13 | 56.24 (17) | C7—S1—C9—C10 | 64.4 (2) |
C8—S2—C12—C14 | −78.77 (18) | Pd—S1—C9—C10 | 170.97 (16) |
Pd—S2—C12—C14 | 179.03 (15) | C1—C6—C5—C4 | −2.9 (4) |
C5—C6—C1—C2 | 3.4 (3) | C8—C6—C5—C4 | 174.7 (2) |
C8—C6—C1—C2 | −174.3 (2) | C6—C5—C4—C3 | 0.1 (4) |
C5—C6—C1—Pd | −174.32 (17) | C5—C4—C3—C2 | 2.1 (4) |
C8—C6—C1—Pd | 8.1 (3) | C1—C2—C3—C4 | −1.6 (4) |
S1—Pd—C1—C2 | 9.58 (18) | C7—C2—C3—C4 | −180.0 (2) |
Experimental details
Crystal data | |
Chemical formula | [PdBr(C14H21S2)] |
Mr | 439.77 |
Crystal system, space group | Monoclinic, P21/c |
Temperature (K) | 173 |
a, b, c (Å) | 8.5591 (2), 10.6777 (2), 17.6816 (4) |
β (°) | 103.042 (1) |
V (Å3) | 1574.3 (1) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 3.96 |
Crystal size (mm) | 0.30 × 0.26 × 0.18 |
Data collection | |
Diffractometer | Nonius KappaCCD area-detector diffractometer |
Absorption correction | Empirical (using intensity measurements) (SCALEPACK; Otwinowski & Minor, 1997) |
Tmin, Tmax | 0.350, 0.490 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 14692, 3557, 3143 |
Rint | 0.023 |
(sin θ/λ)max (Å−1) | 0.649 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.024, 0.052, 1.08 |
No. of reflections | 3557 |
No. of parameters | 168 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 1.07, −0.60 |
Computer programs: COLLECT (Nonius, 2001), SCALEPACK (Otwinowski & Minor, 1997), SCALEPACK, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), ORTEP-3 for Windows (Farrugia, 1997), PLATON (Spek, 1997).
Pd—C1 | 1.984 (2) | Pd—S2 | 2.3110 (6) |
Pd—S1 | 2.2924 (6) | Pd—Br | 2.5471 (3) |
C1—Pd—S1 | 85.08 (7) | C1—Pd—Br | 178.91 (7) |
C1—Pd—S2 | 85.17 (7) | S1—Pd—Br | 94.549 (17) |
S1—Pd—S2 | 170.19 (2) | S2—Pd—Br | 95.180 (16) |
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Thiopincer ligand complexes are formed by the cyclometallation of 1,3-bis(disubstitutedthiomethyl)benzene. The compounds [PdCl{C6H3(CH2StBu)2-2,6}] (Errington et al., 1980), and [PdCl{C6H3(CH2SCH2CH3)2-2,6}] and [PdCl{C6H3(CH2SC6H5)2-2,6}] (Lucena et al., 1996) have been prepared by this method. These complexes have been used as catalysts for various reactions, such as the catalytic dehydrogenation of alkanes (Gupta et al., 1996, 1997; Liu et al., 1999), ethers and alkylarenes (Dijkstra et al., 2001; Gorla et al., 1994; Langmire et al., 1998; Stark et al., 2000), and as Lewis acid catalysts (Dijkstra et al., 2001). They are also used as catalysts for aldol reactions between benzaldehydes and methyl isocyanoacetate (Espinet et al., 1994), as hydrogen transfer catalysts (Dani et al., 2000) and as SO2 reversible binding sites in gas sensor materials (Albrecht & van Koten, 1999; Albrecht et al., 2000).
Recently, we have used pincer ligand complexes as starting materials for potential metallomesogens by reacting [PdBr{C6H3(CH2SiPr)2-2,6}] with long-chain alkoxy aryl thiols in the presence of Et3N. This is a methodology employed in preparing a number of metal thiolato complexes (Darkwa & Milius, 1996; Darkwa et al., 1998; Nevondo et al., 2000; Moutloali et al., 2001). However, in the attempt to react [PdBr{C6H3(CH2SiPr)2-2,6}], (I), with thiols, (I) crystallized from the reaction mixture instead of forming a palladium thiolato complex. This indicates that Et3N might be too weak a base to effect the desired reaction. The structure of the title palladium complex, (I), is reported here. \sch
The molecular structure of (I) is shown in Fig. 1 and selected bond distances and angles are given in Table 1. The coordination number of the Pd in (I) is four and the donor atoms are arranged in a square plane, with the S atoms trans to each other. The two Pd—S distances differ only slightly. This is in contrast with similar compounds in which the S atoms are cis to each other. In these compounds, the Pd—S distances differ significantly. For example, the two Pd—S distances [2.274 (2) and 2.256 (2) Å] in [Pd(C6H12S3)Br2] (Wieghart et al., 1986) are noticeably different.
In compound (I), the 1,3-bis(thiomethyl)benzene unit behaves as a tridentate ligand. Its two S atoms are separated by a distance of 4.587 (8) Å and are therefore suitably disposed to form two Pd—S bonds orientated trans to each other. The two isopropyl substituents are in axial positions on the same sides of the molecular plane, whereas the tert-butyl groups are on opposite sides in [PdCl(C6H4)(CH2SiPr)2] (reference? Please provide a reference for this compound). The axial conformation is preferred, as the isopropyl repulsions are minimized. Potential repulsion between the two isopropyl substituents is also minimized when they are on opposite sides. However, in contrast with the tert-butyl analogue, the two isopropyl groups in (I) are cis to each other. In this conformation, the shortest distance between H atoms is 2.315 (7) Å.