Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270113010226/yf3030sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270113010226/yf3030Isup2.hkl | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270113010226/yf3030IIsup3.hkl |
CCDC references: 950381; 950382
For related literature, see: Allen (2002); Becker et al. (2001); Bruker (2001); Iwasaki & Iwasaki (1972); Khan et al. (1986); Levason et al. (2013); Nelson et al. (2008); Olmstead et al. (1988); Raveendran & Pal (2008); Rong et al. (2012); Rosokha et al. (2006).
Under an inert atmosphere, SiCl4 (85 mg, 0.5 mmol) and tribenzylphosphane (304 mg, 1.0 mmol) were dissolved in CH2Cl2 (10 ml) and stirred at 295 K for 4 h. The solution was then concentrated to approximately 5 ml and cooled to 255 K. After 16 h, colourless blocks of (I) precipitated which were isolated by decanting the supernatant. Keeping the supernatant at 255 K for several weeks resulted in the precipitation of colourless plates of compound (II), which were isolated by decanting the supernatant.
H atoms attached to C atoms were placed in geometrically assigned positions, with C—H = 0.95 (CH) or 0.99 Å (CH2), and refined using a riding model, with Uiso(H) = 1.2Ueq(C). In (II), H atoms attached to heteroatoms were located in Fourier difference maps and the distances allowed to refine freely. However, the Uiso value of atom H2 (attached to phosphorus) was restrained to 1.2Ueq(P2).
The crystal system of (II) was determined as trigonal with the space group initially assigned as R3. However, the solution in this space group was clearly incorrect (short intermolecular P—H···H—P contacts and unsatisfactory R values), hence the space group was reassigned as R3, wherein the solution was routine.
Data collection: CrystalClear-SM Expert (Rigaku, 2012) for (I); CrystalClear-SM Expert (Rigaku, 2011) for (II). Cell refinement: CrystalClear-SM Expert (Rigaku, 2012) for (I); CrystalClear-SM Expert (Rigaku, 2011) for (II). Data reduction: CrystalClear-SM Expert (Rigaku, 2012) for (I); CrystalClear-SM Expert (Rigaku, 2011) for (II). For both compounds, program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 2012); software used to prepare material for publication: PLATON (Spek, 2009), WinGX (Farrugia, 2012), enCIFer (Allen et al., 2004), publCIF (Westrip, 2010) and Mercury (Macrae et al., 2006).
C21H21P | F(000) = 648 |
Mr = 304.35 | Dx = 1.205 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2yn | Cell parameters from 3384 reflections |
a = 10.9287 (8) Å | θ = 2.5–27.5° |
b = 9.5775 (7) Å | µ = 0.16 mm−1 |
c = 16.0272 (12) Å | T = 100 K |
β = 91.051 (5)° | Platelet, colourless |
V = 1677.3 (2) Å3 | 0.09 × 0.04 × 0.01 mm |
Z = 4 |
Rigaku Saturn724+ (2x2 bin mode) diffractometer | 3374 independent reflections |
Radiation source: Rotating Anode | 2268 reflections with I > 2σ(I) |
Confocal monochromator | Rint = 0.048 |
Detector resolution: 28.5714 pixels mm-1 | θmax = 26.4°, θmin = 3.1° |
profile data from ω scans | h = −12→13 |
Absorption correction: multi-scan (CrystalClear-SM Expert; Rigaku, 2012) | k = −11→11 |
Tmin = 0.986, Tmax = 0.998 | l = −18→20 |
7381 measured reflections |
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)] = 0.049 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.109 | H-atom parameters constrained |
S = 1.01 | w = 1/[σ2(Fo2) + (0.0391P)2 + 0.8781P] where P = (Fo2 + 2Fc2)/3 |
3374 reflections | (Δ/σ)max < 0.001 |
199 parameters | Δρmax = 0.36 e Å−3 |
0 restraints | Δρmin = −0.36 e Å−3 |
C21H21P | V = 1677.3 (2) Å3 |
Mr = 304.35 | Z = 4 |
Monoclinic, P21/n | Mo Kα radiation |
a = 10.9287 (8) Å | µ = 0.16 mm−1 |
b = 9.5775 (7) Å | T = 100 K |
c = 16.0272 (12) Å | 0.09 × 0.04 × 0.01 mm |
β = 91.051 (5)° |
Rigaku Saturn724+ (2x2 bin mode) diffractometer | 3374 independent reflections |
Absorption correction: multi-scan (CrystalClear-SM Expert; Rigaku, 2012) | 2268 reflections with I > 2σ(I) |
Tmin = 0.986, Tmax = 0.998 | Rint = 0.048 |
7381 measured reflections |
R[F2 > 2σ(F2)] = 0.049 | 0 restraints |
wR(F2) = 0.109 | H-atom parameters constrained |
S = 1.01 | Δρmax = 0.36 e Å−3 |
3374 reflections | Δρmin = −0.36 e Å−3 |
199 parameters |
Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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 | 0.5006 (2) | 0.4221 (2) | 0.30990 (15) | 0.0200 (5) | |
H1A | 0.5209 | 0.4306 | 0.3701 | 0.024* | |
H1B | 0.4273 | 0.4803 | 0.2982 | 0.024* | |
C2 | 0.4701 (2) | 0.2722 (2) | 0.29062 (14) | 0.0173 (5) | |
C3 | 0.5304 (2) | 0.1643 (3) | 0.33218 (14) | 0.0195 (5) | |
H3 | 0.5913 | 0.1861 | 0.3732 | 0.023* | |
C4 | 0.5036 (2) | 0.0256 (3) | 0.31504 (14) | 0.0217 (5) | |
H4 | 0.5458 | −0.0469 | 0.3441 | 0.026* | |
C5 | 0.4146 (2) | −0.0068 (3) | 0.25502 (14) | 0.0230 (5) | |
H5 | 0.3953 | −0.1015 | 0.2431 | 0.028* | |
C6 | 0.3546 (2) | 0.0991 (3) | 0.21302 (15) | 0.0235 (6) | |
H6 | 0.2943 | 0.0769 | 0.1717 | 0.028* | |
C7 | 0.3812 (2) | 0.2375 (3) | 0.23029 (14) | 0.0203 (5) | |
H7 | 0.3388 | 0.3094 | 0.2009 | 0.024* | |
C8 | 0.5464 (2) | 0.5451 (3) | 0.15258 (14) | 0.0193 (5) | |
H8A | 0.5026 | 0.4634 | 0.1288 | 0.023* | |
H8B | 0.4846 | 0.6165 | 0.1668 | 0.023* | |
C9 | 0.6307 (2) | 0.6037 (2) | 0.08820 (14) | 0.0188 (5) | |
C10 | 0.6884 (2) | 0.5141 (3) | 0.03304 (14) | 0.0230 (5) | |
H10 | 0.6735 | 0.4165 | 0.0364 | 0.028* | |
C11 | 0.7669 (2) | 0.5643 (3) | −0.02667 (15) | 0.0259 (6) | |
H11 | 0.8055 | 0.5014 | −0.0637 | 0.031* | |
C12 | 0.7892 (2) | 0.7059 (3) | −0.03255 (15) | 0.0237 (6) | |
H12 | 0.8423 | 0.7407 | −0.0740 | 0.028* | |
C13 | 0.7338 (2) | 0.7969 (3) | 0.02228 (15) | 0.0219 (5) | |
H13 | 0.7495 | 0.8943 | 0.0189 | 0.026* | |
C14 | 0.6552 (2) | 0.7457 (3) | 0.08223 (15) | 0.0200 (5) | |
H14 | 0.6177 | 0.8088 | 0.1197 | 0.024* | |
C15 | 0.6419 (2) | 0.6646 (2) | 0.30018 (15) | 0.0207 (5) | |
H15A | 0.6825 | 0.7305 | 0.2620 | 0.025* | |
H15B | 0.5584 | 0.7003 | 0.3102 | 0.025* | |
C16 | 0.7123 (2) | 0.6607 (2) | 0.38159 (14) | 0.0170 (5) | |
C17 | 0.6551 (2) | 0.6783 (2) | 0.45773 (15) | 0.0204 (5) | |
H17 | 0.5691 | 0.6923 | 0.4590 | 0.025* | |
C18 | 0.7228 (2) | 0.6755 (3) | 0.53188 (15) | 0.0213 (5) | |
H18 | 0.6829 | 0.6877 | 0.5835 | 0.026* | |
C19 | 0.8479 (2) | 0.6552 (2) | 0.53089 (14) | 0.0206 (5) | |
H19 | 0.8941 | 0.6537 | 0.5817 | 0.025* | |
C20 | 0.9056 (2) | 0.6370 (2) | 0.45531 (14) | 0.0196 (5) | |
H20 | 0.9916 | 0.6229 | 0.4542 | 0.024* | |
C21 | 0.8383 (2) | 0.6394 (2) | 0.38182 (14) | 0.0179 (5) | |
H21 | 0.8785 | 0.6262 | 0.3304 | 0.021* | |
P1 | 0.63037 (6) | 0.49121 (7) | 0.24908 (4) | 0.01694 (16) |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.0231 (13) | 0.0185 (13) | 0.0183 (12) | 0.0008 (11) | 0.0012 (10) | −0.0004 (10) |
C2 | 0.0201 (12) | 0.0170 (12) | 0.0148 (12) | −0.0019 (10) | 0.0035 (9) | −0.0006 (10) |
C3 | 0.0216 (12) | 0.0205 (13) | 0.0163 (12) | −0.0022 (10) | −0.0015 (9) | −0.0020 (10) |
C4 | 0.0269 (13) | 0.0187 (13) | 0.0196 (12) | −0.0003 (11) | 0.0030 (10) | 0.0032 (10) |
C5 | 0.0306 (13) | 0.0174 (13) | 0.0212 (12) | −0.0070 (11) | 0.0046 (10) | −0.0027 (11) |
C6 | 0.0226 (13) | 0.0279 (15) | 0.0201 (13) | −0.0083 (11) | −0.0030 (10) | −0.0021 (11) |
C7 | 0.0203 (12) | 0.0235 (13) | 0.0172 (12) | 0.0004 (10) | 0.0006 (10) | 0.0017 (10) |
C8 | 0.0206 (12) | 0.0181 (12) | 0.0190 (12) | −0.0010 (10) | −0.0047 (9) | −0.0001 (10) |
C9 | 0.0195 (12) | 0.0206 (13) | 0.0161 (12) | −0.0012 (10) | −0.0064 (9) | 0.0023 (10) |
C10 | 0.0320 (13) | 0.0174 (13) | 0.0195 (12) | −0.0026 (11) | −0.0005 (10) | −0.0004 (11) |
C11 | 0.0333 (14) | 0.0247 (14) | 0.0197 (13) | 0.0004 (12) | 0.0005 (11) | −0.0025 (11) |
C12 | 0.0234 (13) | 0.0299 (15) | 0.0175 (12) | −0.0020 (11) | −0.0028 (10) | 0.0063 (11) |
C13 | 0.0243 (13) | 0.0160 (13) | 0.0249 (13) | −0.0006 (10) | −0.0094 (10) | 0.0047 (11) |
C14 | 0.0222 (12) | 0.0186 (13) | 0.0191 (12) | 0.0029 (10) | −0.0059 (10) | 0.0000 (10) |
C15 | 0.0254 (13) | 0.0129 (12) | 0.0234 (13) | −0.0001 (10) | −0.0059 (10) | 0.0012 (10) |
C16 | 0.0208 (12) | 0.0091 (11) | 0.0209 (12) | 0.0009 (10) | −0.0014 (10) | 0.0009 (10) |
C17 | 0.0200 (12) | 0.0145 (12) | 0.0268 (13) | 0.0003 (10) | 0.0017 (10) | −0.0008 (10) |
C18 | 0.0306 (14) | 0.0159 (12) | 0.0176 (12) | −0.0031 (11) | 0.0067 (10) | −0.0009 (10) |
C19 | 0.0333 (14) | 0.0149 (12) | 0.0135 (12) | −0.0020 (11) | −0.0059 (10) | 0.0017 (10) |
C20 | 0.0234 (13) | 0.0146 (12) | 0.0208 (12) | 0.0013 (10) | −0.0022 (10) | 0.0018 (10) |
C21 | 0.0235 (13) | 0.0128 (12) | 0.0175 (12) | −0.0006 (10) | 0.0020 (10) | −0.0002 (10) |
P1 | 0.0197 (3) | 0.0146 (3) | 0.0165 (3) | −0.0011 (3) | −0.0016 (2) | −0.0001 (3) |
C1—C2 | 1.505 (3) | C11—C12 | 1.381 (4) |
C1—P1 | 1.858 (2) | C11—H11 | 0.9500 |
C1—H1A | 0.9900 | C12—C13 | 1.385 (3) |
C1—H1B | 0.9900 | C12—H12 | 0.9500 |
C2—C3 | 1.389 (3) | C13—C14 | 1.390 (3) |
C2—C7 | 1.398 (3) | C13—H13 | 0.9500 |
C3—C4 | 1.387 (3) | C14—H14 | 0.9500 |
C3—H3 | 0.9500 | C15—C16 | 1.503 (3) |
C4—C5 | 1.391 (3) | C15—P1 | 1.855 (2) |
C4—H4 | 0.9500 | C15—H15A | 0.9900 |
C5—C6 | 1.376 (4) | C15—H15B | 0.9900 |
C5—H5 | 0.9500 | C16—C17 | 1.391 (3) |
C6—C7 | 1.385 (3) | C16—C21 | 1.392 (3) |
C6—H6 | 0.9500 | C17—C18 | 1.388 (3) |
C7—H7 | 0.9500 | C17—H17 | 0.9500 |
C8—C9 | 1.504 (3) | C18—C19 | 1.381 (3) |
C8—P1 | 1.857 (2) | C18—H18 | 0.9500 |
C8—H8A | 0.9900 | C19—C20 | 1.387 (3) |
C8—H8B | 0.9900 | C19—H19 | 0.9500 |
C9—C14 | 1.391 (3) | C20—C21 | 1.378 (3) |
C9—C10 | 1.391 (3) | C20—H20 | 0.9500 |
C10—C11 | 1.384 (3) | C21—H21 | 0.9500 |
C10—H10 | 0.9500 | ||
C2—C1—P1 | 113.61 (16) | C10—C11—H11 | 120.0 |
C2—C1—H1A | 108.8 | C11—C12—C13 | 119.6 (2) |
P1—C1—H1A | 108.8 | C11—C12—H12 | 120.2 |
C2—C1—H1B | 108.8 | C13—C12—H12 | 120.2 |
P1—C1—H1B | 108.8 | C12—C13—C14 | 120.0 (2) |
H1A—C1—H1B | 107.7 | C12—C13—H13 | 120.0 |
C3—C2—C7 | 118.2 (2) | C14—C13—H13 | 120.0 |
C3—C2—C1 | 120.7 (2) | C13—C14—C9 | 121.0 (2) |
C7—C2—C1 | 121.1 (2) | C13—C14—H14 | 119.5 |
C4—C3—C2 | 121.4 (2) | C9—C14—H14 | 119.5 |
C4—C3—H3 | 119.3 | C16—C15—P1 | 113.00 (16) |
C2—C3—H3 | 119.3 | C16—C15—H15A | 109.0 |
C3—C4—C5 | 119.5 (2) | P1—C15—H15A | 109.0 |
C3—C4—H4 | 120.2 | C16—C15—H15B | 109.0 |
C5—C4—H4 | 120.2 | P1—C15—H15B | 109.0 |
C6—C5—C4 | 119.7 (2) | H15A—C15—H15B | 107.8 |
C6—C5—H5 | 120.2 | C17—C16—C21 | 118.4 (2) |
C4—C5—H5 | 120.2 | C17—C16—C15 | 121.9 (2) |
C5—C6—C7 | 120.7 (2) | C21—C16—C15 | 119.8 (2) |
C5—C6—H6 | 119.6 | C18—C17—C16 | 120.5 (2) |
C7—C6—H6 | 119.6 | C18—C17—H17 | 119.7 |
C6—C7—C2 | 120.4 (2) | C16—C17—H17 | 119.7 |
C6—C7—H7 | 119.8 | C19—C18—C17 | 120.3 (2) |
C2—C7—H7 | 119.8 | C19—C18—H18 | 119.9 |
C9—C8—P1 | 112.04 (16) | C17—C18—H18 | 119.9 |
C9—C8—H8A | 109.2 | C18—C19—C20 | 119.6 (2) |
P1—C8—H8A | 109.2 | C18—C19—H19 | 120.2 |
C9—C8—H8B | 109.2 | C20—C19—H19 | 120.2 |
P1—C8—H8B | 109.2 | C21—C20—C19 | 120.0 (2) |
H8A—C8—H8B | 107.9 | C21—C20—H20 | 120.0 |
C14—C9—C10 | 118.0 (2) | C19—C20—H20 | 120.0 |
C14—C9—C8 | 122.2 (2) | C20—C21—C16 | 121.2 (2) |
C10—C9—C8 | 119.7 (2) | C20—C21—H21 | 119.4 |
C11—C10—C9 | 121.2 (2) | C16—C21—H21 | 119.4 |
C11—C10—H10 | 119.4 | C15—P1—C8 | 98.48 (11) |
C9—C10—H10 | 119.4 | C15—P1—C1 | 97.69 (11) |
C12—C11—C10 | 120.1 (2) | C8—P1—C1 | 99.53 (11) |
C12—C11—H11 | 120.0 | ||
P1—C1—C2—C3 | 86.5 (2) | C10—C9—C14—C13 | 0.8 (4) |
P1—C1—C2—C7 | −93.1 (2) | C8—C9—C14—C13 | 179.8 (2) |
C7—C2—C3—C4 | −0.3 (3) | P1—C15—C16—C17 | −109.5 (2) |
C1—C2—C3—C4 | −179.9 (2) | P1—C15—C16—C21 | 70.6 (3) |
C2—C3—C4—C5 | 0.0 (3) | C21—C16—C17—C18 | 0.5 (3) |
C3—C4—C5—C6 | 0.4 (3) | C15—C16—C17—C18 | −179.4 (2) |
C4—C5—C6—C7 | −0.5 (3) | C16—C17—C18—C19 | 0.0 (4) |
C5—C6—C7—C2 | 0.3 (4) | C17—C18—C19—C20 | −0.2 (4) |
C3—C2—C7—C6 | 0.1 (3) | C18—C19—C20—C21 | 0.0 (4) |
C1—C2—C7—C6 | 179.7 (2) | C19—C20—C21—C16 | 0.4 (4) |
P1—C8—C9—C14 | −92.7 (2) | C17—C16—C21—C20 | −0.7 (3) |
P1—C8—C9—C10 | 86.4 (2) | C15—C16—C21—C20 | 179.2 (2) |
C14—C9—C10—C11 | −0.6 (4) | C16—C15—P1—C8 | −177.50 (17) |
C8—C9—C10—C11 | −179.7 (2) | C16—C15—P1—C1 | 81.60 (19) |
C9—C10—C11—C12 | −0.1 (4) | C9—C8—P1—C15 | 82.23 (18) |
C10—C11—C12—C13 | 0.8 (4) | C9—C8—P1—C1 | −178.44 (17) |
C11—C12—C13—C14 | −0.7 (4) | C2—C1—P1—C15 | −174.85 (17) |
C12—C13—C14—C9 | −0.1 (4) | C2—C1—P1—C8 | 85.16 (19) |
C42H43P2+·HCl2− | Dx = 1.286 Mg m−3 |
Mr = 681.61 | Mo Kα radiation, λ = 0.71073 Å |
Trigonal, R3 | Cell parameters from 2232 reflections |
Hall symbol: R 3 | θ = 2.1–27.4° |
a = 13.941 (5) Å | µ = 0.31 mm−1 |
c = 15.693 (7) Å | T = 100 K |
V = 2641.3 (18) Å3 | Block, colourless |
Z = 3 | 0.06 × 0.04 × 0.03 mm |
F(000) = 1080 |
Rigaku Saturn724+ (2x2 bin mode) diffractometer | 1664 independent reflections |
Radiation source: fine-focus sealed tube | 1414 reflections with I > 2σ(I) |
Confocal monochromator | Rint = 0.022 |
Detector resolution: 28.5714 pixels mm-1 | θmax = 27.4°, θmin = 3.1° |
profile data from ω–scans | h = −18→8 |
Absorption correction: multi-scan (CrystalClear-SM Expert; Rigaku, 2011) | k = −12→17 |
Tmin = 0.982, Tmax = 0.991 | l = −20→11 |
2521 measured reflections |
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)] = 0.042 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.099 | w = 1/[σ2(Fo2) + (0.0533P)2] where P = (Fo2 + 2Fc2)/3 |
S = 1.02 | (Δ/σ)max < 0.001 |
1664 reflections | Δρmax = 0.61 e Å−3 |
142 parameters | Δρmin = −0.57 e Å−3 |
1 restraint | Absolute structure: Flack (1983), 325 Friedel pairs |
Primary atom site location: structure-invariant direct methods | Absolute structure parameter: 0.34 (14) |
C42H43P2+·HCl2− | Z = 3 |
Mr = 681.61 | Mo Kα radiation |
Trigonal, R3 | µ = 0.31 mm−1 |
a = 13.941 (5) Å | T = 100 K |
c = 15.693 (7) Å | 0.06 × 0.04 × 0.03 mm |
V = 2641.3 (18) Å3 |
Rigaku Saturn724+ (2x2 bin mode) diffractometer | 1664 independent reflections |
Absorption correction: multi-scan (CrystalClear-SM Expert; Rigaku, 2011) | 1414 reflections with I > 2σ(I) |
Tmin = 0.982, Tmax = 0.991 | Rint = 0.022 |
2521 measured reflections |
R[F2 > 2σ(F2)] = 0.042 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.099 | Δρmax = 0.61 e Å−3 |
S = 1.02 | Δρmin = −0.57 e Å−3 |
1664 reflections | Absolute structure: Flack (1983), 325 Friedel pairs |
142 parameters | Absolute structure parameter: 0.34 (14) |
1 restraint |
Geometry. All s.u.'s (except the s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'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 > 2σ(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 | 0.7408 (4) | 0.2664 (3) | 0.5748 (2) | 0.0219 (9) | |
H1A | 0.6962 | 0.1861 | 0.5870 | 0.026* | |
H1B | 0.7503 | 0.2757 | 0.5123 | 0.026* | |
C2 | 0.8536 (3) | 0.3121 (3) | 0.6161 (2) | 0.0179 (8) | |
C3 | 0.8675 (4) | 0.2586 (3) | 0.6871 (2) | 0.0188 (8) | |
H3 | 0.8054 | 0.1945 | 0.7100 | 0.023* | |
C4 | 0.9695 (4) | 0.2979 (4) | 0.7236 (2) | 0.0246 (10) | |
H4 | 0.9784 | 0.2599 | 0.7705 | 0.030* | |
C5 | 1.0613 (3) | 0.3944 (4) | 0.6917 (2) | 0.0215 (9) | |
H5 | 1.1320 | 0.4225 | 0.7175 | 0.026* | |
C6 | 1.0482 (4) | 0.4478 (4) | 0.6232 (2) | 0.0228 (9) | |
H6 | 1.1098 | 0.5131 | 0.6013 | 0.027* | |
C7 | 0.9445 (3) | 0.4062 (3) | 0.5858 (2) | 0.0209 (9) | |
H7 | 0.9363 | 0.4436 | 0.5382 | 0.025* | |
C8 | 0.5926 (4) | 0.3968 (4) | 0.9179 (2) | 0.0238 (9) | |
H8A | 0.5855 | 0.3801 | 0.9796 | 0.029* | |
H8B | 0.6363 | 0.4782 | 0.9109 | 0.029* | |
C9 | 0.4792 (3) | 0.3541 (3) | 0.8800 (2) | 0.0188 (8) | |
C10 | 0.3866 (3) | 0.2587 (3) | 0.9116 (2) | 0.0212 (9) | |
H10 | 0.3949 | 0.2210 | 0.9589 | 0.025* | |
C11 | 0.2836 (4) | 0.2187 (4) | 0.8749 (2) | 0.0225 (9) | |
H11 | 0.2216 | 0.1535 | 0.8965 | 0.027* | |
C12 | 0.2708 (3) | 0.2744 (4) | 0.8057 (2) | 0.0234 (9) | |
H12 | 0.1998 | 0.2482 | 0.7810 | 0.028* | |
C13 | 0.3610 (4) | 0.3671 (4) | 0.7734 (2) | 0.0225 (10) | |
H13 | 0.3524 | 0.4043 | 0.7259 | 0.027* | |
C14 | 0.4654 (4) | 0.4070 (4) | 0.8102 (2) | 0.0244 (10) | |
H14 | 0.5276 | 0.4708 | 0.7871 | 0.029* | |
P1 | 0.6667 | 0.3333 | 0.61180 (14) | 0.0249 (4) | |
P2 | 0.6667 | 0.3333 | 0.86636 (12) | 0.0258 (5) | |
Cl1 | 0.6667 | 0.3333 | 0.15629 (12) | 0.0371 (5) | |
Cl2 | 0.6667 | 0.3333 | 0.35858 (12) | 0.0363 (5) | |
H1 | 0.6667 | 0.3333 | 0.273 (4) | 0.05 (2)* | |
H2 | 0.6667 | 0.3333 | 0.790 (5) | 0.064* |
U11 | U22 | U33 | U12 | U13 | U23 | |
C1 | 0.023 (2) | 0.021 (2) | 0.026 (2) | 0.014 (2) | −0.0001 (16) | −0.0016 (16) |
C2 | 0.024 (2) | 0.018 (2) | 0.0178 (17) | 0.0151 (19) | −0.0015 (15) | −0.0048 (14) |
C3 | 0.017 (2) | 0.015 (2) | 0.0218 (18) | 0.0064 (18) | 0.0028 (15) | 0.0004 (15) |
C4 | 0.030 (3) | 0.026 (3) | 0.021 (2) | 0.017 (2) | −0.0033 (17) | 0.0015 (16) |
C5 | 0.018 (2) | 0.024 (2) | 0.0222 (19) | 0.0100 (19) | −0.0035 (16) | −0.0067 (16) |
C6 | 0.023 (2) | 0.020 (2) | 0.0229 (19) | 0.009 (2) | 0.0072 (16) | 0.0011 (16) |
C7 | 0.025 (2) | 0.024 (2) | 0.0168 (17) | 0.014 (2) | 0.0026 (15) | −0.0003 (15) |
C8 | 0.022 (2) | 0.023 (2) | 0.0232 (19) | 0.009 (2) | −0.0015 (16) | −0.0005 (16) |
C9 | 0.018 (2) | 0.020 (2) | 0.0195 (18) | 0.0106 (18) | −0.0013 (15) | −0.0038 (15) |
C10 | 0.021 (2) | 0.025 (2) | 0.0199 (19) | 0.014 (2) | 0.0017 (16) | 0.0001 (15) |
C11 | 0.021 (2) | 0.024 (2) | 0.022 (2) | 0.011 (2) | 0.0026 (16) | −0.0005 (16) |
C12 | 0.021 (2) | 0.032 (3) | 0.025 (2) | 0.018 (2) | −0.0031 (16) | −0.0066 (17) |
C13 | 0.032 (3) | 0.022 (2) | 0.0192 (19) | 0.018 (2) | −0.0010 (16) | −0.0017 (15) |
C14 | 0.030 (3) | 0.024 (2) | 0.0221 (19) | 0.016 (2) | 0.0032 (16) | 0.0013 (16) |
P1 | 0.0183 (6) | 0.0183 (6) | 0.0381 (9) | 0.0092 (3) | 0.000 | 0.000 |
P2 | 0.0168 (6) | 0.0168 (6) | 0.0436 (13) | 0.0084 (3) | 0.000 | 0.000 |
Cl1 | 0.0305 (7) | 0.0305 (7) | 0.0502 (11) | 0.0152 (4) | 0.000 | 0.000 |
Cl2 | 0.0282 (7) | 0.0282 (7) | 0.0526 (13) | 0.0141 (3) | 0.000 | 0.000 |
C1—C2 | 1.515 (5) | C8—H8B | 0.9900 |
C1—P1 | 1.800 (4) | C9—C14 | 1.386 (5) |
C1—H1A | 0.9900 | C9—C10 | 1.402 (5) |
C1—H1B | 0.9900 | C10—C11 | 1.380 (6) |
C2—C7 | 1.376 (5) | C10—H10 | 0.9500 |
C2—C3 | 1.407 (5) | C11—C12 | 1.397 (5) |
C3—C4 | 1.368 (6) | C11—H11 | 0.9500 |
C3—H3 | 0.9500 | C12—C13 | 1.372 (6) |
C4—C5 | 1.405 (6) | C12—H12 | 0.9500 |
C4—H4 | 0.9500 | C13—C14 | 1.397 (6) |
C5—C6 | 1.371 (5) | C13—H13 | 0.9500 |
C5—H5 | 0.9500 | C14—H14 | 0.9500 |
C6—C7 | 1.389 (6) | P1—C1i | 1.800 (4) |
C6—H6 | 0.9500 | P1—C1ii | 1.800 (4) |
C7—H7 | 0.9500 | P2—C8ii | 1.847 (4) |
C8—C9 | 1.506 (5) | P2—C8i | 1.847 (4) |
C8—P2 | 1.847 (4) | P2—H2 | 1.19 (7) |
C8—H8A | 0.9900 | Cl2—H1 | 1.35 (7) |
C2—C1—P1 | 112.9 (3) | H8A—C8—H8B | 108.0 |
C2—C1—H1A | 109.0 | C14—C9—C10 | 118.5 (4) |
P1—C1—H1A | 109.0 | C14—C9—C8 | 119.9 (4) |
C2—C1—H1B | 109.0 | C10—C9—C8 | 121.5 (3) |
P1—C1—H1B | 109.0 | C11—C10—C9 | 120.9 (4) |
H1A—C1—H1B | 107.8 | C11—C10—H10 | 119.5 |
C7—C2—C3 | 118.3 (4) | C9—C10—H10 | 119.5 |
C7—C2—C1 | 121.4 (3) | C10—C11—C12 | 119.7 (4) |
C3—C2—C1 | 120.3 (4) | C10—C11—H11 | 120.1 |
C4—C3—C2 | 120.7 (4) | C12—C11—H11 | 120.1 |
C4—C3—H3 | 119.7 | C13—C12—C11 | 119.9 (4) |
C2—C3—H3 | 119.7 | C13—C12—H12 | 120.0 |
C3—C4—C5 | 120.1 (4) | C11—C12—H12 | 120.0 |
C3—C4—H4 | 120.0 | C12—C13—C14 | 120.3 (4) |
C5—C4—H4 | 120.0 | C12—C13—H13 | 119.9 |
C6—C5—C4 | 119.6 (4) | C14—C13—H13 | 119.9 |
C6—C5—H5 | 120.2 | C9—C14—C13 | 120.6 (4) |
C4—C5—H5 | 120.2 | C9—C14—H14 | 119.7 |
C5—C6—C7 | 119.9 (4) | C13—C14—H14 | 119.7 |
C5—C6—H6 | 120.1 | C1—P1—C1i | 110.14 (15) |
C7—C6—H6 | 120.1 | C1—P1—C1ii | 110.14 (15) |
C2—C7—C6 | 121.5 (4) | C1i—P1—C1ii | 110.14 (15) |
C2—C7—H7 | 119.3 | C8ii—P2—C8i | 102.28 (16) |
C6—C7—H7 | 119.3 | C8ii—P2—C8 | 102.28 (16) |
C9—C8—P2 | 111.5 (3) | C8i—P2—C8 | 102.28 (16) |
C9—C8—H8A | 109.3 | C8ii—P2—H2 | 115.95 (14) |
P2—C8—H8A | 109.3 | C8i—P2—H2 | 115.95 (14) |
C9—C8—H8B | 109.3 | C8—P2—H2 | 115.95 (13) |
P2—C8—H8B | 109.3 | ||
P1—C1—C2—C7 | −83.3 (4) | C14—C9—C10—C11 | −0.8 (6) |
P1—C1—C2—C3 | 96.5 (4) | C8—C9—C10—C11 | −178.2 (4) |
C7—C2—C3—C4 | −1.6 (6) | C9—C10—C11—C12 | −0.6 (6) |
C1—C2—C3—C4 | 178.5 (3) | C10—C11—C12—C13 | 1.5 (6) |
C2—C3—C4—C5 | 1.8 (6) | C11—C12—C13—C14 | −0.9 (6) |
C3—C4—C5—C6 | −1.0 (6) | C10—C9—C14—C13 | 1.4 (6) |
C4—C5—C6—C7 | 0.0 (6) | C8—C9—C14—C13 | 178.8 (4) |
C3—C2—C7—C6 | 0.6 (6) | C12—C13—C14—C9 | −0.5 (6) |
C1—C2—C7—C6 | −179.5 (3) | C2—C1—P1—C1i | −169.8 (3) |
C5—C6—C7—C2 | 0.2 (6) | C2—C1—P1—C1ii | 68.5 (4) |
P2—C8—C9—C14 | −88.9 (4) | C9—C8—P2—C8ii | −78.7 (4) |
P2—C8—C9—C10 | 88.5 (4) | C9—C8—P2—C8i | 175.6 (3) |
Symmetry codes: (i) −x+y+1, −x+1, z; (ii) −y+1, x−y, z. |
D—H···A | D—H | H···A | D···A | D—H···A |
Cl2—H1···Cl1 | 1.35 (7) | 1.83 (7) | 3.175 (3) | 180 |
P2—H2···P1 | 1.19 (7) | 2.80 (7) | 3.995 (3) | 180 (1) |
Experimental details
(I) | (II) | |
Crystal data | ||
Chemical formula | C21H21P | C42H43P2+·HCl2− |
Mr | 304.35 | 681.61 |
Crystal system, space group | Monoclinic, P21/n | Trigonal, R3 |
Temperature (K) | 100 | 100 |
a, b, c (Å) | 10.9287 (8), 9.5775 (7), 16.0272 (12) | 13.941 (5), 13.941 (5), 15.693 (7) |
α, β, γ (°) | 90, 91.051 (5), 90 | 90, 90, 120 |
V (Å3) | 1677.3 (2) | 2641.3 (18) |
Z | 4 | 3 |
Radiation type | Mo Kα | Mo Kα |
µ (mm−1) | 0.16 | 0.31 |
Crystal size (mm) | 0.09 × 0.04 × 0.01 | 0.06 × 0.04 × 0.03 |
Data collection | ||
Diffractometer | Rigaku Saturn724+ (2x2 bin mode) diffractometer | Rigaku Saturn724+ (2x2 bin mode) diffractometer |
Absorption correction | Multi-scan (CrystalClear-SM Expert; Rigaku, 2012) | Multi-scan (CrystalClear-SM Expert; Rigaku, 2011) |
Tmin, Tmax | 0.986, 0.998 | 0.982, 0.991 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 7381, 3374, 2268 | 2521, 1664, 1414 |
Rint | 0.048 | 0.022 |
(sin θ/λ)max (Å−1) | 0.625 | 0.648 |
Refinement | ||
R[F2 > 2σ(F2)], wR(F2), S | 0.049, 0.109, 1.01 | 0.042, 0.099, 1.02 |
No. of reflections | 3374 | 1664 |
No. of parameters | 199 | 142 |
No. of restraints | 0 | 1 |
H-atom treatment | H-atom parameters constrained | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 0.36, −0.36 | 0.61, −0.57 |
Absolute structure | ? | Flack (1983), 325 Friedel pairs |
Absolute structure parameter | ? | 0.34 (14) |
Computer programs: CrystalClear-SM Expert (Rigaku, 2012), CrystalClear-SM Expert (Rigaku, 2011), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ORTEP-3 (Farrugia, 2012), PLATON (Spek, 2009), WinGX (Farrugia, 2012), enCIFer (Allen et al., 2004), publCIF (Westrip, 2010) and Mercury (Macrae et al., 2006)..
C1—P1 | 1.858 (2) | C15—P1 | 1.855 (2) |
C8—P1 | 1.857 (2) | ||
C15—P1—C8 | 98.48 (11) | C8—P1—C1 | 99.53 (11) |
C15—P1—C1 | 97.69 (11) | ||
P1—C1—C2—C3 | 86.5 (2) | P1—C8—C9—C10 | 86.4 (2) |
P1—C1—C2—C7 | −93.1 (2) | P1—C15—C16—C17 | −109.5 (2) |
P1—C8—C9—C14 | −92.7 (2) | P1—C15—C16—C21 | 70.6 (3) |
C1—P1 | 1.800 (4) | P2—H2 | 1.19 (7) |
C8—P2 | 1.847 (4) | Cl2—H1 | 1.35 (7) |
C1—P1—C1i | 110.14 (15) | C8—P2—H2 | 115.95 (13) |
C8i—P2—C8 | 102.28 (16) | ||
P1—C1—C2—C7 | −83.3 (4) | P2—C8—C9—C14 | −88.9 (4) |
P1—C1—C2—C3 | 96.5 (4) | P2—C8—C9—C10 | 88.5 (4) |
Symmetry code: (i) −x+y+1, −x+1, z. |
D—H···A | D—H | H···A | D···A | D—H···A |
Cl2—H1···Cl1 | 1.35 (7) | 1.83 (7) | 3.175 (3) | 180.0 |
P2—H2···P1 | 1.19 (7) | 2.80 (7) | 3.995 (3) | 180.000 (1) |
Subscribe to Acta Crystallographica Section C: Structural Chemistry
The full text of this article is available to subscribers to the journal.
- Information on subscribing
- Sample issue
- Purchase subscription
- Reduced-price subscriptions
- If you have already subscribed, you may need to register
Phosphanes are ubiquitous ligands in the coordination chemistry of transition metals, but their coordination chemistry with main group elements is less well explored. During recent work into the synthesis of phosphane complexes of halosilanes (Levason et al., 2013), we attempted the reaction of tribenzylphosphane, (I), with SiCl4 in CH2Cl2.
Although no complex was formed between (I) and SiCl4, colourless crystals of tribenzylphosphane (Fig. 1) were isolated instead by cooling a CH2Cl2 solution of the reaction mixture to 255 K for 16 h. Somewhat surprisingly, the solid-state structure of tribenzylphosphane had not previously been obtained despite its commercial availability and the presence of almost 100 metal complexes of tribenzylphosphane in the Cambridge Structural Database (CSD; November 2012 update; Allen, 2002).
Compound (I) crystallized in the monoclinic space group P21/n with the C—P bond lengths (Table 1) being unremarkable. The space group and cell dimensions of (I) were different to that of the antimony analogue tribenzylstibine (Becker et al., 2001), which crystallized in the orthorhombic space group Pbca. The cell dimensions were also notably different to the nitrogen analogue, tribenzylamine, which was twice determined to be monoclinic with different settings of the same space group. Determinations at 203 K as P21/a (Iwasaki & Iwasaki, 1972) and another at 120 K as P21/c (Nelson et al., 2008) contained β angles of 92.82 (1) (120 K) and 93.9 (2)° (203 K). It is notable that compound (I) has a β angle of 90.90 (1)°, indicating that as the atomic radius of the pnictogen increases, the β–angle decreases until it reaches 90° for tribenzylstibine. Analogues with the other pnictogens, tribenzylarsine and tribenzylbismuthine, have not been crystallographically characterized.
Analysis of the C—X—C bond angles (X = N, P or Sb) reveals that this series of molecules is consistent with classical VSEPR theory which holds that as the central atom gets larger, there is less steric repulsion between the electron pairs around the central atom, hence they move closer together. All determinations for NBz3 contain C—N—C angles of ~110°, very close to the ideal for a trigonal pyramidal structure, indicating that the lone pair on nitrogen is not significantly distorting the geometry of the molecule. In contrast, PBz3 and SbBz3 with larger central atoms both contain C—X—C bond angles <100°, much smaller than for an ideal trigonal pyramid.
The packing of compound (I) is dominated by face-edge π interactions between alternating up and down molecules (Fig. 2). The distances between the C—H donor and the acceptor (the mean plane defined by the six C atoms in the phenyl ring) range from 2.529 (4) [H10i–mean(C16–C21)] to 2.634 (4) Å [H3i–mean(C9–C14)]. The C16–C21 ring is also an acceptor from H13ii [2.578 (4) Å] and the fourth interaction is between H21ii and the C2–C7 ring [2.583 (3) Å] [symmetry codes: (i) -x+3/4, y+1/2, -z+1/2; (ii) -x+3/4, y-1/2, -z+1/2].
These alternating molecules form columns which stack parallel to the b axis (Fig. 3). The majority of the face-edge π-interactions are between neighbouring molecules within a single column, but a few intercolumnar interactions are present which cause the columns to align in a sheet parallel to the [101] direction. The intercolumnar interaction of 2.651 (4) Å is between H18iii (donor) and C2 (acceptor; the distance is calculated to the mean plane of the carbons in the entire C1–C7 benzyl group owing to the short H18iii–C1 interaction) and is slightly longer than the face-edge π-interactions which form the columns [symmetry code: (iii) -x+1, -y+1, -z+1]. Notably, this acceptor is external to the phenyl ring: similar interactions (albeit intramolecular) have been observed in the solid state structure of transition metal benzyl compounds (Rong et al., 2012, and references therein).
In contrast, SbBz3 packs in alternating ABAB columns which run parallel to the b axis. The face-edge π interactions of 2.71 Å are confined to molecules within a single column hence there are no intercolumnar interactions (Becker et al., 2001). The nitrogen analogue (P21/a) packs in a similar manner to compound (I), with columns of alternating up and down molecules running parallel to the b axis. Here, two types of intermolecular C—H···π interaction are present: one involving an aryl CH (2.580 Å to the neighbouring aryl ring) and the other involving one hydrogen from a benzyl CH2 group (2.826 Å to the neighbouring aryl ring) (Iwasaki & Iwasaki, 1972). The P21/c determination, however, only contains one CH–π interaction from an aryl CH donor (2.626 Å) with one of the benzyl CH2 H atoms being involved in a short contact (2.393 Å) to a neighbouring benzyl CH2 hydrogen (Nelson et al., 2008). A cocrystal of NBz3 and CBr4 has also been determined where the packing is dominated by dimers of NBz3 molecules linked by face-edge π interactions, one from an aryl CH (2.842 Å) and another from an alkyl CH2 group (2.860 Å). These dimers stack into columns which are bounded by columns of CBr4 molecules (Rosokha et al., 2006).
A second crop of colourless crystals was grown after keeping the same solution, from which (I) was obtained, for several weeks at 255 K. These had a different morphology to the previous crystals: the resulting product came from the partial hydrolysis of SiCl4 which formed the hydrochloride salt of tribenzylphosphane in situ.
The crystal system of (II) was determined as trigonal, with XPREP (Bruker, 2001) indicating the space group R3. The asymmetric unit consisted of one-third of a tribenzylphosphonium cation and one-third of a chloride anion lying on a C3 axis. The solution in this space group led to problems with short intermolecular P—H···H—P contacts (~1.4 Å), as well as stubbornly high R values (R[F2 > 2σ(F2)] > 0.1), hence it was redetermined in R3. The asymmetric unit now clearly showed the true formulation of (II), whereby one tribenzylphosphane moiety acts as a hydrogen-bond acceptor to a tribenzylphosphonium cation (Bz3P–H···PBz3) counterbalanced by a Cl—H···Cl anion (Fig. 4). The R values were also much more satisfactory (see below) despite the pseudosymmetry causing level B alerts in checkCIF.
The dichloride anion has been observed 30 times in the Cambridge Structural Database (CSD; February 2013 update; Allen, 2002) and in keeping with previously observed structures (bar those where the Cl—H bonds are related by symmetry), the Cl—H distances are significantly different to each other (Tables 2 and 3). The hydrogen(bisphosphane) cation group is unique; the only other molecule in the CSD with a P—H—P arrangement of atoms is bis(hexamethyldisilazido)phosphane (Olmstead et al., 1988) which exists as a hydrogen-bridged dimer in the solid state. However, the core of the molecule is a P2H2 ring, with P—H—P bond angles of 97 (2) and 99 (2)°, which contrasts to the P—H—P core of (II) which is linear.
Compound (II) is also the only structurally characterized example of a tribenzylphosphonium group. The C—P bond lengths (Table 2) appear to be slightly shorter than those in compound (I), but this can only be confirmed for the C1—P1 bond; the C2—P2 bond length is not significantly different from those in (I) within experimental error (Table 1). The C—P—C angles (Table 2) show two distinct P-atom environments. The phosphane acting as an acceptor (P1) has a C—P—C bond angle consistent with an ideal trigonal–pyramidal geometry, whereas the formal phosphonium cation (P2) has a C—P—C bond angle much smaller than for an ideal tetrahedral geometry. The distortion away from an ideal tetrahedron can also be seen in the C—P—H bond angle (Table 2), which is significantly larger than expected for an ideal tetrahedron. This is likely a result of the phosphane distorting to form the C—H···π interactions which are a major part of the structure.
Each aryl ring in compound (II) acts as both an acceptor and a donor, forming a circular network of C—H···π interactions around the core of the molecule (Fig. 4). The two distances of 2.663 (3) [H14iii···mean(C2–C7)] and 2.664 (5) Å [H3iii···mean(C9–C14)], which are not symmetry related, are identical [symmetry code: (iv) -x+y+1, -x+1, z]. These are longer than the intracolumnar face-edge π-interactions in (I), but are consistent with the length of the intercolumnar interactions. Also present are intermolecular interactions of 2.697 (5) [H10iv···mean(C2–C7)] and 2.683 (6) Å [H7v···mean(C9–C14)], the result of which is to form a three-dimensional network of interconnected cations (Fig. 5) [symmetry codes: (v) -x+y+4/3, -x+2/3, z-1/3; (vi) -x+y+2/3, -x+4/3, z+1/3]. The conformation of the benzyl groups in (II) is restricted by these donor–acceptor interactions such that the P—C—C—C torsion angles are all very close to 90° (Table 2). This contrasts to compound (I) where the lack of donor–acceptor interactions results in a much wider range of torsion angles, with large deviations (up to 20°) from 90° (Table 1).
The formation of the novel hydrogenbis(phosphane) cation is probably driven by the ability of tribenzylphosphane to form a sterically bulky cage, stabilized by face-edge π-interactions, around the central P—H···P group. The flexibility, imparted by the methylene group, between the aryl ring and phosphorus in (II) is key to the formation of the cage; other phosphonium salts with aryl groups e.g. triphenylphosphonium cations (see, for example, Khan et al., 1986; Raveendran & Pal, 2008) do not contain this structural motif. It should also be noted that this cage is not the most stable arrangement of molecules of the type EBz3: it is not found in (I) (E = P) nor is it found in other Group 15 analogues (E = N or Sb), indicating that the combination of face-edge π-interactions and the P—H···P donor–acceptor group is required for the cage to form.