Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270100015213/br1295sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270100015213/br1295Iasup2.hkl | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270100015213/br1295IIsup3.hkl |
CCDC references: 158243; 158244
The previously reported arachno compounds (Ia) and (Ib) were prepared as described by Bould et al. (1984). Single crystals of (Ia) were obtained by diffusion of pentane through a benzene layer into a CDCl3 solution of the compound. The previously unreported nido compound, (II), was isolated from the thermolysis of the arachno compound (Ib) as follows. A finely ground mixture of [4,4,4,4-(CO)(PMe3)2H-4-IrB8H11-2-Cl] [(Ib), 73 mg, 145 µmol] and B10H14 (0.51 g, 4200 µmol) was placed in a 10 mm soda glass NMR tube which was then evacuated, refilled with nitrogen and heated in an oil bath at 396 K for 55 min, after which time the excess B10H14 was removed by sublimation (357 K, ca 0.01 mm H g). Thin-layer chromatography of the residue (Aldrich standard grade silica gel with gypsum binder and fluorescent indicator, 70:30 CH2Cl2/hexane) showed a number of diffuse faint yellow and red bands between RF 0.1 and 0.8. Separation and identification of these bands proved difficult, but one yellow band, at RF 0.1, after further separation by high-performance liquid chromatography [silica, Lichosorb Si60 7 µm, 260 × 16 mm column, CH2Cl2/hexane (80:20, 5 ml min-1), RT 15 min] and crystallization by diffusion of pentane through a benzene layer into a CDCl3 solution of the compound, gave crystals of (II) suitable for diffraction analysis (2 mg, 4 µmol, 3%). NMR spectroscopic analysis: (p.p.m., CDCl3, 300 K, Bruker 250 ARX spectrometer, δ(11B) [δ(1H) in square brackets]: B1 19.9 [4.77], B4 19.9 (site of Cl substituent), B6 - 4.8 [3.01], B3, B8, B9 - 12.2 [-1.35] -14.2 (2) [-2.8 and -1.30], B5 - 35.8 [0.14], B7 - 51.7 [-1.11]; 1H NMR (δ, p.p.m.): H2/H5 - 14.46 [2J(31P-1H) 62 Hz], H6/H9 and H8/H9 - 2.76 and -2.02, P(CH3)3 1.91 and 1.78 [2J(31P-1H) 10 Hz]; 31P NMR (δ, p.p.m.): -42.0 and -51.5.
Data were collected for compound (Ia) using a mixture of area-detector ω and ϕ exposures, with the CCD detector positioned 30 mm from the sample. Methyl H atoms were constrained to calculated positions with isotropic displacement parameters equal to 1.2Ueq of the parent C atom. Cluster-associated H atoms were located via Fourier difference syntheses and were included in structure factor calculations but were not refined. For both compounds, all boron-cage H atoms were located from the difference Fourier map and were refined freely. Non-boron-cage H atoms were included in their idealized geometry and were treated with the appropriate riding model (AFIX in? SHELXTL; Sheldrick, 1998). Please clarify - s.u.s only given for (II).
Data collection: COLLECT (Nonius, 1998) for (Ia); SMART (Bruker, 1997) for (II). Cell refinement: DENZO-SMN (Otwinowski & Minor, 1996) for (Ia); SMART for (II). Data reduction: DENZO-SMN for (Ia); SAINT (Bruker, 1997) for (II). For both compounds, program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997). Molecular graphics: ORTEX (McArdle, 1995) for (Ia); SHELXTL (Sheldrick, 1998) for (II). For both compounds, software used to prepare material for publication: local program.
[IrH(B8H12)(C3H9P)2(CO)] | F(000) = 912 |
Mr = 471.94 | Dx = 1.638 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
a = 9.2035 (2) Å | Cell parameters from 11332 reflections |
b = 15.9788 (5) Å | θ = 1–27.5° |
c = 13.2013 (3) Å | µ = 7.13 mm−1 |
β = 99.670 (2)° | T = 150 K |
V = 1913.81 (8) Å3 | Prism, colourless |
Z = 4 | 0.62 × 0.25 × 0.11 mm |
Nonius KappaCCD area-detector diffractometer | 3737 independent reflections |
Radiation source: Fine-focus sealed tube | 3547 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.075 |
Detector resolution: 9.091 pixels mm-1 | θmax = 26°, θmin = 3.0° |
1° ϕ scans for χ = 0°, 1° ω scans for χ = 90° | h = −11→11 |
Absorption correction: multi-scan (SORTAV; Blessing, 1995) | k = −19→19 |
Tmin = 0.096, Tmax = 0.508 | l = −16→16 |
15922 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)] = 0.041 | H atoms treated by a mixture of independent and constrained refinement |
wR(F2) = 0.105 | w = 1/[σ2(Fo2) + (0.0588P)2 + 4.8183P] where P = (Fo2 + 2Fc2)/3 |
S = 1.10 | (Δ/σ)max = 0.001 |
3737 reflections | Δρmax = 2.01 e Å−3 |
179 parameters | Δρmin = −2.88 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: 0.0037 (5) |
[IrH(B8H12)(C3H9P)2(CO)] | V = 1913.81 (8) Å3 |
Mr = 471.94 | Z = 4 |
Monoclinic, P21/n | Mo Kα radiation |
a = 9.2035 (2) Å | µ = 7.13 mm−1 |
b = 15.9788 (5) Å | T = 150 K |
c = 13.2013 (3) Å | 0.62 × 0.25 × 0.11 mm |
β = 99.670 (2)° |
Nonius KappaCCD area-detector diffractometer | 3737 independent reflections |
Absorption correction: multi-scan (SORTAV; Blessing, 1995) | 3547 reflections with I > 2σ(I) |
Tmin = 0.096, Tmax = 0.508 | Rint = 0.075 |
15922 measured reflections |
R[F2 > 2σ(F2)] = 0.041 | 0 restraints |
wR(F2) = 0.105 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.10 | Δρmax = 2.01 e Å−3 |
3737 reflections | Δρmin = −2.88 e Å−3 |
179 parameters |
Experimental. PLEASE NOTE cell_measurement_ fields are not relevant to area detector data, the entire data set is used to refine the cell, which is indexed from all observed reflections in a 10° ϕ range. Detector set at 30 mm from sample with different 2θ offsets. 1° ϕ exposures for χ = 0° settings, 1° ω exposures for χ = 90° settings |
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 > 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 | ||
Ir4 | 0.04951 (2) | 0.162921 (12) | 0.114177 (13) | 0.02470 (14) | |
H4 | 0.0858 | 0.0643 | 0.1171 | 0.03* | |
C1 | −0.0339 (7) | 0.1480 (4) | −0.0250 (5) | 0.0334 (12) | |
O1 | −0.0874 (6) | 0.1340 (4) | −0.1078 (4) | 0.0576 (12) | |
P1 | 0.2957 (2) | 0.17093 (9) | 0.09333 (13) | 0.0322 (3) | |
C11 | 0.3930 (8) | 0.0739 (5) | 0.1210 (7) | 0.064 (2) | |
H11A | 0.3416 | 0.0294 | 0.0781 | 0.096* | |
H11B | 0.3968 | 0.0597 | 0.1937 | 0.096* | |
H11C | 0.4934 | 0.0796 | 0.1065 | 0.096* | |
C12 | 0.3291 (7) | 0.1918 (5) | −0.0359 (5) | 0.0453 (15) | |
H12A | 0.4354 | 0.1909 | −0.0366 | 0.068* | |
H12B | 0.2894 | 0.247 | −0.0581 | 0.068* | |
H12C | 0.2806 | 0.1489 | −0.0827 | 0.068* | |
C13 | 0.4160 (7) | 0.2466 (5) | 0.1677 (6) | 0.056 (2) | |
H13A | 0.4075 | 0.2415 | 0.2405 | 0.084* | |
H13B | 0.3873 | 0.3032 | 0.1436 | 0.084* | |
H13C | 0.5181 | 0.2361 | 0.1593 | 0.084* | |
P2 | 0.0012 (2) | 0.30854 (10) | 0.10708 (10) | 0.0310 (3) | |
C21 | 0.0615 (8) | 0.3635 (5) | 0.0001 (5) | 0.049 (2) | |
H21A | 0.0278 | 0.4217 | −0.0012 | 0.073* | |
H21B | 0.0198 | 0.336 | −0.0646 | 0.073* | |
H21C | 0.1694 | 0.3622 | 0.0087 | 0.073* | |
C22 | −0.1938 (9) | 0.3353 (4) | 0.0875 (6) | 0.047 (2) | |
H22A | −0.2054 | 0.3958 | 0.0773 | 0.071* | |
H22B | −0.2358 | 0.3185 | 0.1479 | 0.071* | |
H22C | −0.2453 | 0.306 | 0.0267 | 0.071* | |
C23 | 0.0803 (8) | 0.3728 (4) | 0.2165 (5) | 0.0447 (15) | |
H23A | 0.188 | 0.3701 | 0.2255 | 0.067* | |
H23B | 0.0472 | 0.352 | 0.2786 | 0.067* | |
H23C | 0.0481 | 0.4309 | 0.2041 | 0.067* | |
B1 | −0.0623 (7) | 0.1731 (4) | 0.2528 (5) | 0.0283 (13) | |
H1 | −0.0949 | 0.2395 | 0.2644 | 0.034* | |
B2 | −0.1763 (7) | 0.0909 (4) | 0.2821 (5) | 0.0346 (13) | |
H2 | −0.2786 | 0.1019 | 0.3156 | 0.042* | |
B3 | −0.0038 (7) | 0.1093 (4) | 0.3588 (5) | 0.0341 (13) | |
H3 | −0.0024 | 0.1314 | 0.4395 | 0.041* | |
B5 | −0.1714 (7) | 0.1168 (5) | 0.1500 (5) | 0.0340 (14) | |
H5 | −0.2668 | 0.1433 | 0.1034 | 0.041* | |
H56 | −0.1523 | 0.0585 | 0.109 | 0.041* | |
B6 | −0.1866 (8) | 0.0075 (5) | 0.1978 (6) | 0.0400 (15) | |
H6 | −0.3011 | −0.0251 | 0.1842 | 0.048* | |
H67 | −0.0773 | −0.0415 | 0.2143 | 0.048* | |
B7 | −0.0535 (8) | 0.0059 (5) | 0.3178 (6) | 0.043 (2) | |
H7 | −0.0682 | −0.0524 | 0.361 | 0.051* | |
H78 | 0.1037 | −0.0155 | 0.3019 | 0.051* | |
B8 | 0.1403 (8) | 0.0416 (5) | 0.3439 (5) | 0.0388 (14) | |
H8 | 0.2162 | 0.0071 | 0.418 | 0.047* | |
H89 | 0.1901 | 0.0825 | 0.2778 | 0.047* | |
B9 | 0.1298 (8) | 0.1493 (5) | 0.2858 (6) | 0.0356 (15) | |
H9 | 0.1926 | 0.1827 | 0.3184 | 0.043* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Ir4 | 0.0232 (2) | 0.0314 (2) | 0.0200 (2) | −0.00028 (6) | 0.00525 (10) | −0.00015 (6) |
C1 | 0.030 (3) | 0.043 (3) | 0.025 (3) | 0.005 (2) | −0.002 (2) | 0.000 (2) |
O1 | 0.065 (3) | 0.070 (4) | 0.034 (3) | 0.008 (3) | −0.003 (2) | −0.011 (2) |
P1 | 0.0251 (7) | 0.0407 (9) | 0.0327 (8) | −0.0017 (5) | 0.0100 (6) | 0.0029 (6) |
C11 | 0.040 (4) | 0.065 (5) | 0.093 (6) | 0.016 (3) | 0.030 (4) | 0.030 (4) |
C12 | 0.046 (4) | 0.056 (4) | 0.041 (3) | −0.008 (3) | 0.027 (3) | −0.004 (3) |
C13 | 0.036 (3) | 0.085 (6) | 0.048 (4) | −0.016 (3) | 0.011 (3) | −0.011 (4) |
P2 | 0.0352 (7) | 0.0353 (8) | 0.0232 (7) | 0.0032 (6) | 0.0072 (5) | 0.0008 (6) |
C21 | 0.062 (4) | 0.044 (4) | 0.043 (4) | 0.003 (3) | 0.019 (3) | 0.014 (3) |
C22 | 0.051 (4) | 0.045 (4) | 0.048 (4) | 0.014 (3) | 0.014 (3) | 0.007 (3) |
C23 | 0.059 (4) | 0.041 (4) | 0.035 (3) | −0.005 (3) | 0.010 (3) | −0.011 (3) |
B1 | 0.033 (3) | 0.032 (3) | 0.023 (3) | −0.001 (2) | 0.015 (3) | −0.001 (2) |
B2 | 0.033 (3) | 0.039 (4) | 0.034 (3) | 0.001 (3) | 0.013 (3) | 0.002 (3) |
B3 | 0.036 (3) | 0.042 (4) | 0.027 (3) | 0.002 (3) | 0.011 (3) | 0.003 (3) |
B5 | 0.027 (3) | 0.048 (4) | 0.027 (3) | −0.002 (3) | 0.007 (2) | −0.004 (3) |
B6 | 0.034 (3) | 0.045 (4) | 0.044 (4) | −0.007 (3) | 0.016 (3) | −0.005 (3) |
B7 | 0.046 (4) | 0.045 (4) | 0.041 (4) | −0.001 (3) | 0.017 (3) | 0.006 (3) |
B8 | 0.043 (4) | 0.040 (4) | 0.035 (3) | 0.002 (3) | 0.012 (3) | 0.005 (3) |
B9 | 0.034 (3) | 0.039 (4) | 0.034 (4) | −0.009 (3) | 0.005 (3) | 0.000 (3) |
Ir4—C1 | 1.883 (6) | B1—B2 | 1.764 (9) |
Ir4—B1 | 2.251 (6) | B1—B5 | 1.789 (9) |
Ir4—B9 | 2.272 (8) | B1—B9 | 1.789 (10) |
Ir4—B5 | 2.285 (6) | B2—B6 | 1.727 (10) |
Ir4—P1 | 2.3319 (15) | B2—B3 | 1.759 (9) |
Ir4—P2 | 2.368 (2) | B2—B7 | 1.779 (10) |
C1—O1 | 1.143 (7) | B2—B5 | 1.800 (9) |
P1—C11 | 1.797 (7) | B3—B8 | 1.748 (9) |
P1—C13 | 1.813 (7) | B3—B7 | 1.774 (10) |
P1—C12 | 1.814 (6) | B3—B9 | 1.802 (9) |
P2—C22 | 1.821 (8) | B5—B6 | 1.870 (10) |
P2—C23 | 1.821 (6) | B6—B7 | 1.832 (11) |
P2—C21 | 1.827 (6) | B7—B8 | 1.850 (10) |
B1—B3 | 1.743 (9) | B8—B9 | 1.879 (10) |
C1—Ir4—B1 | 129.4 (3) | B6—B2—B7 | 63.0 (4) |
C1—Ir4—B9 | 166.2 (3) | B3—B2—B7 | 60.2 (4) |
B1—Ir4—B9 | 46.6 (3) | B1—B2—B7 | 104.6 (4) |
C1—Ir4—B5 | 86.0 (2) | B6—B2—B5 | 64.0 (4) |
B1—Ir4—B5 | 46.4 (2) | B3—B2—B5 | 110.7 (4) |
B9—Ir4—B5 | 85.1 (2) | B1—B2—B5 | 60.2 (4) |
C1—Ir4—P1 | 97.9 (2) | B7—B2—B5 | 108.3 (4) |
B1—Ir4—P1 | 132.7 (2) | B1—B3—B8 | 114.1 (4) |
B9—Ir4—P1 | 87.9 (2) | B1—B3—B2 | 60.5 (4) |
B5—Ir4—P1 | 163.4 (2) | B8—B3—B2 | 117.4 (5) |
C1—Ir4—P2 | 92.5 (2) | B1—B3—B7 | 105.7 (5) |
B1—Ir4—P2 | 81.5 (2) | B8—B3—B7 | 63.4 (4) |
B9—Ir4—P2 | 99.3 (2) | B2—B3—B7 | 60.5 (4) |
B5—Ir4—P2 | 99.0 (2) | B1—B3—B9 | 60.6 (4) |
P1—Ir4—P2 | 96.96 (5) | B8—B3—B9 | 63.9 (4) |
O1—C1—Ir4 | 175.7 (6) | B2—B3—B9 | 112.4 (5) |
C11—P1—C13 | 103.2 (4) | B7—B3—B9 | 109.3 (5) |
C11—P1—C12 | 101.1 (4) | B1—B5—B2 | 58.9 (3) |
C13—P1—C12 | 101.7 (3) | B1—B5—B6 | 106.1 (4) |
C11—P1—Ir4 | 112.9 (2) | B2—B5—B6 | 56.1 (4) |
C13—P1—Ir4 | 119.3 (2) | B1—B5—Ir4 | 65.8 (3) |
C12—P1—Ir4 | 116.3 (2) | B2—B5—Ir4 | 116.3 (4) |
C22—P2—C23 | 103.5 (3) | B6—B5—Ir4 | 119.4 (4) |
C22—P2—C21 | 101.4 (3) | B2—B6—B7 | 59.9 (4) |
C23—P2—C21 | 102.1 (4) | B2—B6—B5 | 59.9 (4) |
C22—P2—Ir4 | 114.2 (2) | B7—B6—B5 | 103.2 (5) |
C23—P2—Ir4 | 118.4 (2) | B3—B7—B2 | 59.3 (4) |
C21—P2—Ir4 | 115.0 (2) | B3—B7—B6 | 110.6 (5) |
B3—B1—B2 | 60.2 (4) | B2—B7—B6 | 57.1 (4) |
B3—B1—B5 | 111.9 (5) | B3—B7—B8 | 57.6 (4) |
B2—B1—B5 | 60.9 (4) | B2—B7—B8 | 111.3 (5) |
B3—B1—B9 | 61.3 (4) | B6—B7—B8 | 129.8 (5) |
B2—B1—B9 | 112.8 (5) | B3—B8—B7 | 59.0 (4) |
B5—B1—B9 | 118.9 (4) | B3—B8—B9 | 59.5 (4) |
B3—B1—Ir4 | 119.3 (4) | B7—B8—B9 | 103.0 (5) |
B2—B1—Ir4 | 119.6 (4) | B1—B9—B3 | 58.1 (4) |
B5—B1—Ir4 | 67.8 (3) | B1—B9—B8 | 106.0 (4) |
B9—B1—Ir4 | 67.3 (3) | B3—B9—B8 | 56.7 (4) |
B6—B2—B3 | 116.5 (5) | B1—B9—Ir4 | 66.1 (3) |
B6—B2—B1 | 113.8 (4) | B3—B9—Ir4 | 115.5 (4) |
B3—B2—B1 | 59.3 (4) | B8—B9—Ir4 | 118.7 (4) |
[Ir(B8H10Cl)(C3H9P)2(CO)] | F(000) = 968 |
Mr = 504.36 | Dx = 1.766 Mg m−3 Dm = no Mg m−3 Dm measured by not measured |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
a = 9.2655 (1) Å | Cell parameters from 8192 reflections |
b = 12.1784 (1) Å | θ = 2–27° |
c = 16.8668 (1) Å | µ = 7.34 mm−1 |
β = 94.702 (1)° | T = 223 K |
V = 1896.83 (3) Å3 | Rectangular, yellow |
Z = 4 | 0.23 × 0.22 × 0.10 mm |
Nonius KappaCCD? area-detector diffractometer | 4150 independent reflections |
Radiation source: normal-focus sealed tube | 3824 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.038 |
ϕ and ω scans | θmax = 27.0°, θmin = 2.1° |
Absorption correction: empirical (using intensity measurements) (SADABS; Blessing, 1995) | h = −11→11 |
Tmin = 0.283, Tmax = 0.528 | k = −15→15 |
55769 measured reflections | l = −21→21 |
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)] = 0.017 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.041 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.17 | w = 1/[σ2(Fo2) + (0.012P)2 + 2.6P] where P = (Fo2 + 2Fc2)/3 |
4150 reflections | (Δ/σ)max = 0.001 |
221 parameters | Δρmax = 1.00 e Å−3 |
0 restraints | Δρmin = −0.51 e Å−3 |
[Ir(B8H10Cl)(C3H9P)2(CO)] | V = 1896.83 (3) Å3 |
Mr = 504.36 | Z = 4 |
Monoclinic, P21/n | Mo Kα radiation |
a = 9.2655 (1) Å | µ = 7.34 mm−1 |
b = 12.1784 (1) Å | T = 223 K |
c = 16.8668 (1) Å | 0.23 × 0.22 × 0.10 mm |
β = 94.702 (1)° |
Nonius KappaCCD? area-detector diffractometer | 4150 independent reflections |
Absorption correction: empirical (using intensity measurements) (SADABS; Blessing, 1995) | 3824 reflections with I > 2σ(I) |
Tmin = 0.283, Tmax = 0.528 | Rint = 0.038 |
55769 measured reflections |
R[F2 > 2σ(F2)] = 0.017 | 0 restraints |
wR(F2) = 0.041 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.17 | Δρmax = 1.00 e Å−3 |
4150 reflections | Δρmin = −0.51 e Å−3 |
221 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 > 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 | ||
Ir2 | −0.491487 (11) | 0.265072 (8) | −0.314885 (6) | 0.02152 (4) | |
Cl1 | −0.65539 (9) | −0.03900 (7) | −0.15775 (6) | 0.0440 (2) | |
P1 | −0.58407 (10) | 0.23739 (7) | −0.44779 (5) | 0.03146 (17) | |
P2 | −0.25027 (9) | 0.25232 (6) | −0.34079 (5) | 0.02895 (16) | |
O1 | −0.4718 (3) | 0.51658 (19) | −0.32160 (15) | 0.0464 (6) | |
B1 | −0.5458 (4) | 0.0977 (3) | −0.2880 (2) | 0.0271 (7) | |
B3 | −0.4297 (4) | 0.1506 (3) | −0.2098 (2) | 0.0295 (7) | |
B4 | −0.6024 (4) | 0.0947 (3) | −0.1944 (2) | 0.0290 (7) | |
B5 | −0.7063 (4) | 0.1694 (3) | −0.2678 (2) | 0.0280 (7) | |
B6 | −0.4431 (4) | 0.2941 (3) | −0.1792 (2) | 0.0318 (7) | |
B7 | −0.5249 (4) | 0.1907 (3) | −0.1227 (2) | 0.0357 (8) | |
B8 | −0.7127 (4) | 0.2036 (3) | −0.1618 (2) | 0.0337 (8) | |
B9 | −0.6026 (5) | 0.3170 (4) | −0.1258 (2) | 0.0403 (9) | |
C1 | −0.4794 (3) | 0.4230 (3) | −0.32131 (17) | 0.0295 (6) | |
C2 | −0.4818 (5) | 0.1528 (3) | −0.5118 (2) | 0.0518 (10) | |
H2A | −0.3827 | 0.1790 | −0.5100 | 0.078* | |
H2B | −0.5254 | 0.1571 | −0.5660 | 0.078* | |
H2C | −0.4826 | 0.0772 | −0.4938 | 0.078* | |
C3 | −0.6099 (4) | 0.3625 (3) | −0.5052 (2) | 0.0471 (9) | |
H3A | −0.5199 | 0.4035 | −0.5026 | 0.071* | |
H3B | −0.6845 | 0.4067 | −0.4837 | 0.071* | |
H3C | −0.6391 | 0.3443 | −0.5602 | 0.071* | |
C4 | −0.7615 (4) | 0.1749 (4) | −0.4605 (2) | 0.0578 (11) | |
H4A | −0.7605 | 0.1059 | −0.4318 | 0.087* | |
H4B | −0.7871 | 0.1615 | −0.5166 | 0.087* | |
H4C | −0.8322 | 0.2238 | −0.4400 | 0.087* | |
C5 | −0.1220 (3) | 0.2922 (3) | −0.2591 (2) | 0.0405 (8) | |
H5A | −0.1394 | 0.2495 | −0.2123 | 0.061* | |
H5B | −0.1337 | 0.3697 | −0.2478 | 0.061* | |
H5C | −0.0243 | 0.2788 | −0.2734 | 0.061* | |
C6 | −0.1981 (4) | 0.3410 (3) | −0.4203 (2) | 0.0419 (8) | |
H6A | −0.2605 | 0.3268 | −0.4683 | 0.063* | |
H6B | −0.0983 | 0.3262 | −0.4303 | 0.063* | |
H6C | −0.2077 | 0.4172 | −0.4048 | 0.063* | |
C7 | −0.1878 (4) | 0.1161 (3) | −0.3663 (2) | 0.0457 (9) | |
H7A | −0.2504 | 0.0869 | −0.4103 | 0.069* | |
H7B | −0.1904 | 0.0680 | −0.3206 | 0.069* | |
H7C | −0.0894 | 0.1208 | −0.3817 | 0.069* | |
H1 | −0.544 (3) | 0.016 (3) | −0.3286 (18) | 0.030 (8)* | |
H3 | −0.314 (3) | 0.107 (2) | −0.1950 (17) | 0.021 (7)* | |
H5 | −0.807 (4) | 0.150 (3) | −0.301 (2) | 0.038 (9)* | |
H6 | −0.345 (4) | 0.339 (3) | −0.157 (2) | 0.044 (10)* | |
H7 | −0.472 (4) | 0.132 (3) | −0.056 (2) | 0.051 (11)* | |
H8 | −0.802 (4) | 0.180 (3) | −0.130 (2) | 0.045 (10)* | |
H9 | −0.612 (3) | 0.375 (3) | −0.0736 (19) | 0.037 (9)* | |
H25 | −0.658 (4) | 0.270 (3) | −0.284 (2) | 0.052 (11)* | |
H69 | −0.551 (4) | 0.370 (3) | −0.178 (2) | 0.048 (10)* | |
H89 | −0.717 (4) | 0.298 (3) | −0.169 (2) | 0.053 (11)* |
U11 | U22 | U33 | U12 | U13 | U23 | |
Ir2 | 0.02085 (6) | 0.02513 (6) | 0.01844 (6) | −0.00061 (4) | 0.00067 (4) | 0.00186 (4) |
Cl1 | 0.0382 (4) | 0.0392 (4) | 0.0558 (5) | −0.0032 (3) | 0.0117 (4) | 0.0163 (4) |
P1 | 0.0385 (5) | 0.0338 (4) | 0.0211 (4) | −0.0058 (3) | −0.0034 (3) | 0.0030 (3) |
P2 | 0.0247 (4) | 0.0358 (4) | 0.0270 (4) | −0.0004 (3) | 0.0059 (3) | 0.0031 (3) |
O1 | 0.0509 (15) | 0.0294 (13) | 0.0586 (17) | −0.0043 (10) | 0.0018 (13) | 0.0016 (11) |
B1 | 0.0283 (17) | 0.0263 (16) | 0.0267 (16) | 0.0012 (13) | 0.0032 (13) | 0.0040 (13) |
B3 | 0.0264 (17) | 0.0361 (18) | 0.0260 (17) | −0.0020 (14) | 0.0025 (13) | 0.0096 (13) |
B4 | 0.0247 (16) | 0.0319 (17) | 0.0305 (18) | −0.0006 (13) | 0.0043 (14) | 0.0082 (13) |
B5 | 0.0221 (16) | 0.0310 (17) | 0.0307 (17) | −0.0015 (13) | 0.0020 (13) | 0.0042 (13) |
B6 | 0.0322 (18) | 0.044 (2) | 0.0193 (16) | −0.0062 (15) | 0.0020 (13) | −0.0020 (14) |
B7 | 0.0323 (19) | 0.049 (2) | 0.0265 (17) | −0.0080 (16) | 0.0050 (14) | 0.0043 (15) |
B8 | 0.0293 (18) | 0.041 (2) | 0.0326 (18) | −0.0006 (15) | 0.0096 (15) | −0.0004 (15) |
B9 | 0.046 (2) | 0.048 (2) | 0.0286 (19) | −0.0086 (18) | 0.0122 (17) | −0.0078 (16) |
C1 | 0.0275 (15) | 0.0355 (17) | 0.0254 (15) | −0.0014 (12) | 0.0009 (12) | 0.0010 (12) |
C2 | 0.073 (3) | 0.044 (2) | 0.038 (2) | −0.0006 (19) | 0.0047 (19) | −0.0129 (16) |
C3 | 0.065 (3) | 0.044 (2) | 0.0303 (18) | 0.0024 (18) | −0.0043 (17) | 0.0101 (15) |
C4 | 0.054 (2) | 0.083 (3) | 0.0339 (19) | −0.026 (2) | −0.0151 (17) | 0.0094 (19) |
C5 | 0.0240 (16) | 0.056 (2) | 0.0410 (19) | −0.0087 (14) | 0.0008 (14) | 0.0047 (16) |
C6 | 0.0390 (19) | 0.054 (2) | 0.0337 (18) | −0.0065 (16) | 0.0119 (15) | 0.0083 (15) |
C7 | 0.039 (2) | 0.047 (2) | 0.052 (2) | 0.0126 (16) | 0.0110 (17) | −0.0006 (17) |
Ir2—C1 | 1.930 (3) | B6—B9 | 1.814 (5) |
Ir2—B1 | 2.156 (3) | B6—H6 | 1.10 (4) |
Ir2—B3 | 2.291 (3) | B6—H69 | 1.36 (4) |
Ir2—P2 | 2.3174 (8) | B7—B9 | 1.697 (6) |
Ir2—B6 | 2.323 (3) | B7—B8 | 1.816 (5) |
Ir2—P1 | 2.3578 (8) | B7—H7 | 1.39 (4) |
Ir2—B5 | 2.491 (3) | B8—B9 | 1.793 (6) |
Ir2—H25 | 1.67 (4) | B8—H8 | 1.07 (4) |
Cl1—B4 | 1.823 (3) | B8—H89 | 1.16 (4) |
P1—C4 | 1.809 (4) | B9—H9 | 1.14 (3) |
P1—C3 | 1.811 (3) | B9—H69 | 1.23 (4) |
P1—C2 | 1.815 (4) | B9—H89 | 1.26 (4) |
P2—C5 | 1.810 (3) | C2—H2A | 0.9700 |
P2—C6 | 1.818 (3) | C2—H2B | 0.9700 |
P2—C7 | 1.820 (4) | C2—H2C | 0.9700 |
O1—C1 | 1.142 (4) | C3—H3A | 0.9700 |
B1—B4 | 1.705 (5) | C3—H3B | 0.9700 |
B1—B3 | 1.756 (5) | C3—H3C | 0.9700 |
B1—B5 | 1.781 (5) | C4—H4A | 0.9700 |
B1—H1 | 1.21 (3) | C4—H4B | 0.9700 |
B3—B4 | 1.777 (5) | C4—H4C | 0.9700 |
B3—B6 | 1.830 (5) | C5—H5A | 0.9700 |
B3—B7 | 1.840 (5) | C5—H5B | 0.9700 |
B3—H3 | 1.21 (3) | C5—H5C | 0.9700 |
B4—B5 | 1.758 (5) | C6—H6A | 0.9700 |
B4—B8 | 1.788 (5) | C6—H6B | 0.9700 |
B4—B7 | 1.789 (5) | C6—H6C | 0.9700 |
B5—B8 | 1.841 (5) | C7—H7A | 0.9700 |
B5—H5 | 1.08 (3) | C7—H7B | 0.9700 |
B5—H25 | 1.34 (4) | C7—H7C | 0.9700 |
B6—B7 | 1.785 (5) | ||
C1—Ir2—B1 | 165.75 (13) | B7—B6—B3 | 61.2 (2) |
C1—Ir2—B3 | 129.64 (13) | B9—B6—B3 | 111.3 (3) |
B1—Ir2—B3 | 46.39 (13) | B7—B6—Ir2 | 111.2 (2) |
C1—Ir2—P2 | 89.72 (9) | B9—B6—Ir2 | 114.4 (2) |
B1—Ir2—P2 | 102.81 (9) | B3—B6—Ir2 | 65.71 (15) |
B3—Ir2—P2 | 85.48 (9) | B7—B6—H6 | 122.7 (19) |
C1—Ir2—B6 | 84.04 (13) | B9—B6—H6 | 115.7 (19) |
B1—Ir2—B6 | 88.10 (13) | B3—B6—H6 | 120.0 (19) |
B3—Ir2—B6 | 46.72 (13) | Ir2—B6—H6 | 120.3 (18) |
P2—Ir2—B6 | 94.85 (9) | B7—B6—H69 | 97.6 (16) |
C1—Ir2—P1 | 96.16 (9) | B9—B6—H69 | 42.7 (16) |
B1—Ir2—P1 | 89.51 (9) | B3—B6—H69 | 136.1 (16) |
B3—Ir2—P1 | 134.20 (9) | Ir2—B6—H69 | 91.8 (15) |
P2—Ir2—P1 | 95.31 (3) | H6—B6—H69 | 104 (2) |
B6—Ir2—P1 | 169.84 (9) | B9—B7—B6 | 62.7 (2) |
C1—Ir2—B5 | 122.37 (12) | B9—B7—B4 | 115.2 (3) |
B1—Ir2—B5 | 44.33 (12) | B6—B7—B4 | 105.4 (2) |
B3—Ir2—B5 | 67.93 (11) | B9—B7—B8 | 61.3 (2) |
P2—Ir2—B5 | 146.78 (8) | B6—B7—B8 | 100.5 (3) |
B6—Ir2—B5 | 81.49 (12) | B4—B7—B8 | 59.5 (2) |
P1—Ir2—B5 | 89.90 (8) | B9—B7—B3 | 116.5 (3) |
C1—Ir2—H25 | 92.3 (12) | B6—B7—B3 | 60.6 (2) |
B1—Ir2—H25 | 74.5 (12) | B4—B7—B3 | 58.64 (19) |
B3—Ir2—H25 | 87.9 (13) | B8—B7—B3 | 104.0 (2) |
P2—Ir2—H25 | 172.8 (14) | B9—B7—H7 | 127.4 (15) |
B6—Ir2—H25 | 78.5 (14) | B6—B7—H7 | 131.0 (15) |
P1—Ir2—H25 | 91.3 (14) | B4—B7—H7 | 108.2 (15) |
B5—Ir2—H25 | 30.2 (12) | B8—B7—H7 | 127.2 (15) |
C4—P1—C3 | 102.20 (19) | B3—B7—H7 | 110.7 (15) |
C4—P1—C2 | 101.8 (2) | B4—B8—B9 | 110.6 (3) |
C3—P1—C2 | 102.21 (19) | B4—B8—B7 | 59.5 (2) |
C4—P1—Ir2 | 115.44 (13) | B9—B8—B7 | 56.1 (2) |
C3—P1—Ir2 | 114.21 (12) | B4—B8—B5 | 57.93 (19) |
C2—P1—Ir2 | 118.68 (14) | B9—B8—B5 | 116.1 (3) |
C5—P2—C6 | 101.81 (16) | B7—B8—B5 | 103.1 (2) |
C5—P2—C7 | 102.90 (18) | B4—B8—H8 | 116 (2) |
C6—P2—C7 | 104.93 (17) | B9—B8—H8 | 119 (2) |
C5—P2—Ir2 | 114.93 (12) | B7—B8—H8 | 123.6 (19) |
C6—P2—Ir2 | 114.72 (12) | B5—B8—H8 | 121.2 (19) |
C7—P2—Ir2 | 115.84 (13) | B4—B8—H89 | 135.8 (19) |
B4—B1—B3 | 61.8 (2) | B9—B8—H89 | 44.3 (19) |
B4—B1—B5 | 60.54 (19) | B7—B8—H89 | 98 (2) |
B3—B1—B5 | 98.4 (2) | B5—B8—H89 | 96.9 (19) |
B4—B1—Ir2 | 108.0 (2) | H8—B8—H89 | 108 (3) |
B3—B1—Ir2 | 70.85 (16) | B7—B9—B8 | 62.6 (2) |
B5—B1—Ir2 | 77.87 (16) | B7—B9—B6 | 61.0 (2) |
B4—B1—H1 | 121.7 (15) | B8—B9—B6 | 100.3 (3) |
B3—B1—H1 | 133.6 (15) | B7—B9—H9 | 126.6 (17) |
B5—B1—H1 | 124.4 (15) | B8—B9—H9 | 131.2 (17) |
Ir2—B1—H1 | 130.3 (15) | B6—B9—H9 | 126.8 (17) |
B1—B3—B4 | 57.70 (19) | B7—B9—H69 | 108.2 (18) |
B1—B3—B6 | 120.7 (2) | B8—B9—H69 | 114.1 (17) |
B4—B3—B6 | 104.0 (2) | B6—B9—H69 | 48.7 (17) |
B1—B3—B7 | 113.1 (2) | H9—B9—H69 | 107 (2) |
B4—B3—B7 | 59.2 (2) | B7—B9—H89 | 100.6 (19) |
B6—B3—B7 | 58.2 (2) | B8—B9—H89 | 39.9 (18) |
B1—B3—Ir2 | 62.77 (15) | B6—B9—H89 | 111.2 (18) |
B4—B3—Ir2 | 100.08 (18) | H9—B9—H89 | 117 (2) |
B6—B3—Ir2 | 67.57 (15) | H69—B9—H89 | 92 (2) |
B7—B3—Ir2 | 110.5 (2) | O1—C1—Ir2 | 177.0 (3) |
B1—B3—H3 | 118.2 (14) | P1—C2—H2A | 109.5 |
B4—B3—H3 | 126.6 (14) | P1—C2—H2B | 109.5 |
B6—B3—H3 | 116.4 (14) | H2A—C2—H2B | 109.5 |
B7—B3—H3 | 115.4 (14) | P1—C2—H2C | 109.5 |
Ir2—B3—H3 | 126.3 (14) | H2A—C2—H2C | 109.5 |
B1—B4—B5 | 61.9 (2) | H2B—C2—H2C | 109.5 |
B1—B4—B3 | 60.5 (2) | P1—C3—H3A | 109.5 |
B5—B4—B3 | 98.4 (2) | P1—C3—H3B | 109.5 |
B1—B4—B8 | 119.7 (2) | H3A—C3—H3B | 109.5 |
B5—B4—B8 | 62.5 (2) | P1—C3—H3C | 109.5 |
B3—B4—B8 | 107.8 (2) | H3A—C3—H3C | 109.5 |
B1—B4—B7 | 118.4 (2) | H3B—C3—H3C | 109.5 |
B5—B4—B7 | 107.7 (2) | P1—C4—H4A | 109.5 |
B3—B4—B7 | 62.1 (2) | P1—C4—H4B | 109.5 |
B8—B4—B7 | 61.0 (2) | H4A—C4—H4B | 109.5 |
B1—B4—Cl1 | 116.4 (2) | P1—C4—H4C | 109.5 |
B5—B4—Cl1 | 123.6 (2) | H4A—C4—H4C | 109.5 |
B3—B4—Cl1 | 131.5 (2) | H4B—C4—H4C | 109.5 |
B8—B4—Cl1 | 112.4 (2) | P2—C5—H5A | 109.5 |
B7—B4—Cl1 | 117.3 (2) | P2—C5—H5B | 109.5 |
B4—B5—B1 | 57.60 (19) | H5A—C5—H5B | 109.5 |
B4—B5—B8 | 59.5 (2) | P2—C5—H5C | 109.5 |
B1—B5—B8 | 113.0 (2) | H5A—C5—H5C | 109.5 |
B4—B5—Ir2 | 93.49 (18) | H5B—C5—H5C | 109.5 |
B1—B5—Ir2 | 57.80 (14) | P2—C6—H6A | 109.5 |
B8—B5—Ir2 | 107.08 (19) | P2—C6—H6B | 109.5 |
B4—B5—H5 | 130.8 (18) | H6A—C6—H6B | 109.5 |
B1—B5—H5 | 119.3 (18) | P2—C6—H6C | 109.5 |
B8—B5—H5 | 117.6 (18) | H6A—C6—H6C | 109.5 |
Ir2—B5—H5 | 128.2 (18) | H6B—C6—H6C | 109.5 |
B4—B5—H25 | 116.7 (17) | P2—C7—H7A | 109.5 |
B1—B5—H25 | 96.5 (17) | P2—C7—H7B | 109.5 |
B8—B5—H25 | 92.0 (17) | H7A—C7—H7B | 109.5 |
Ir2—B5—H25 | 38.7 (17) | P2—C7—H7C | 109.5 |
H5—B5—H25 | 112 (3) | H7A—C7—H7C | 109.5 |
B7—B6—B9 | 56.3 (2) | H7B—C7—H7C | 109.5 |
Experimental details
(Ia) | (II) | |
Crystal data | ||
Chemical formula | [IrH(B8H12)(C3H9P)2(CO)] | [Ir(B8H10Cl)(C3H9P)2(CO)] |
Mr | 471.94 | 504.36 |
Crystal system, space group | Monoclinic, P21/n | Monoclinic, P21/n |
Temperature (K) | 150 | 223 |
a, b, c (Å) | 9.2035 (2), 15.9788 (5), 13.2013 (3) | 9.2655 (1), 12.1784 (1), 16.8668 (1) |
α, β, γ (°) | 90, 99.670 (2), 90 | 90, 94.702 (1), 90 |
V (Å3) | 1913.81 (8) | 1896.83 (3) |
Z | 4 | 4 |
Radiation type | Mo Kα | Mo Kα |
µ (mm−1) | 7.13 | 7.34 |
Crystal size (mm) | 0.62 × 0.25 × 0.11 | 0.23 × 0.22 × 0.10 |
Data collection | ||
Diffractometer | Nonius KappaCCD area-detector diffractometer | Nonius KappaCCD? area-detector diffractometer |
Absorption correction | Multi-scan (SORTAV; Blessing, 1995) | Empirical (using intensity measurements) (SADABS; Blessing, 1995) |
Tmin, Tmax | 0.096, 0.508 | 0.283, 0.528 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 15922, 3737, 3547 | 55769, 4150, 3824 |
Rint | 0.075 | 0.038 |
(sin θ/λ)max (Å−1) | 0.617 | 0.639 |
Refinement | ||
R[F2 > 2σ(F2)], wR(F2), S | 0.041, 0.105, 1.10 | 0.017, 0.041, 1.17 |
No. of reflections | 3737 | 4150 |
No. of parameters | 179 | 221 |
H-atom treatment | H atoms treated by a mixture of independent and constrained refinement | H atoms treated by a mixture of independent and constrained refinement |
Δρmax, Δρmin (e Å−3) | 2.01, −2.88 | 1.00, −0.51 |
Computer programs: COLLECT (Nonius, 1998), SMART (Bruker, 1997), DENZO-SMN (Otwinowski & Minor, 1996), SMART, DENZO-SMN, SAINT (Bruker, 1997), SHELXS97 (Sheldrick, 1990), SHELXL97 (Sheldrick, 1997), ORTEX (McArdle, 1995), SHELXTL (Sheldrick, 1998), local program.
Ir4—C1 | 1.883 (6) | Ir4—P1 | 2.3319 (15) |
Ir4—B1 | 2.251 (6) | Ir4—P2 | 2.368 (2) |
Ir4—B9 | 2.272 (8) | C1—O1 | 1.143 (7) |
Ir4—B5 | 2.285 (6) | ||
C1—Ir4—B1 | 129.4 (3) | B5—Ir4—P1 | 163.4 (2) |
C1—Ir4—B9 | 166.2 (3) | C1—Ir4—P2 | 92.5 (2) |
B1—Ir4—B9 | 46.6 (3) | B1—Ir4—P2 | 81.5 (2) |
C1—Ir4—B5 | 86.0 (2) | B9—Ir4—P2 | 99.3 (2) |
B9—Ir4—B5 | 85.1 (2) | B5—Ir4—P2 | 99.0 (2) |
C1—Ir4—P1 | 97.9 (2) | P1—Ir4—P2 | 96.96 (5) |
B1—Ir4—P1 | 132.7 (2) | O1—C1—Ir4 | 175.7 (6) |
B9—Ir4—P1 | 87.9 (2) |
Ir2—C1 | 1.930 (3) | Ir2—P1 | 2.3578 (8) |
Ir2—B1 | 2.156 (3) | Ir2—B5 | 2.491 (3) |
Ir2—B3 | 2.291 (3) | Cl1—B4 | 1.823 (3) |
Ir2—P2 | 2.3174 (8) | O1—C1 | 1.142 (4) |
Ir2—B6 | 2.323 (3) | ||
C1—Ir2—B1 | 165.75 (13) | B1—Ir2—P1 | 89.51 (9) |
C1—Ir2—B3 | 129.64 (13) | B3—Ir2—P1 | 134.20 (9) |
B1—Ir2—B3 | 46.39 (13) | P2—Ir2—P1 | 95.31 (3) |
C1—Ir2—P2 | 89.72 (9) | B6—Ir2—P1 | 169.84 (9) |
B1—Ir2—P2 | 102.81 (9) | C1—Ir2—B5 | 122.37 (12) |
B3—Ir2—P2 | 85.48 (9) | B1—Ir2—B5 | 44.33 (12) |
C1—Ir2—B6 | 84.04 (13) | B3—Ir2—B5 | 67.93 (11) |
B1—Ir2—B6 | 88.10 (13) | P2—Ir2—B5 | 146.78 (8) |
B3—Ir2—B6 | 46.72 (13) | B6—Ir2—B5 | 81.49 (12) |
P2—Ir2—B6 | 94.85 (9) | P1—Ir2—B5 | 89.90 (8) |
C1—Ir2—P1 | 96.16 (9) | O1—C1—Ir2 | 177.0 (3) |
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The arachno-iridanonaborane [4,4,4,4-CO(PMe3)2H-arachno-4-IrB8H12], (Ia), and its chloro analogue [4,4,4,4-(CO)(PMe3)2H-arachno-4-IrB8H11-2-Cl], (Ib), are obtained from the reaction of [IrCl(CO)(PMe3)2] with the [nido-B9H12]- anion (Bould et al., 1982, 1984). In the original reports on these compounds, the arachno structural type was characterized by a single-crystal X-ray diffraction analysis of the chlorinated derivative, (Ib), but the data were of insufficient quality for H-atom location, although they were reasonably positioned from the results of NMR spectroscopy. In the report on the structure of (Ib) it was surmised that the two endo-terminal H atoms may have partial bridging character (hatched lines in the scheme). However, recent experimental observations and theoretical considerations on non-metal-containing arachno nine-vertex species (Hofmann & Schleyer, 1999; Bould et al., 2000) suggest that one of these H atoms may be bridging and one endo-terminal, with rapid equilibration between the two in solution, and it is useful to attempt to investigate their character crystallographically. \sch
Compound (Ib) has the symmetric ligand disposition shown in the scheme. The structural determination of (Ia) (Fig. 1) now confirms that it has the alternative asymmetric ligand disposition reasonably proposed from NMR spectroscopy. Otherwise, interatomic dimensions in (Ia) are very similar to those in (Ib), with the main differences arising principally from metal hydride trans effects. Thus, the Ir4—P2 distance of 2.368 (2) Å trans to the hydride in (Ia) is significantly longer than the cis-to-H Ir4—P distances in (Ib) [2.334 (2) and 2.346 (2) Å] and Ir4—P1 in (Ia) [2.3319 (15) Å]. Although the Cl substituent on B2 has a noticeable effect on the thermodynamic parameters for the arachno → nido closure process (Bould et al., 1984), its absence in (Ia) shows no significant effect on the interatomic dimensions regarding vertex B2 when compared with (Ib). Unfortunately, the H atoms did not refine satisfactorily and their disposition as endo-terminal or bridging H atoms remains unresolved in nine-vertex arachno-metallanonaborane clusters.
The arachno nine-vertex iridaboranes are also interesting starting materials for a good variety of interesting metallaborane chemistry (Bould et al., 1996, 1997). Fusion of arachno metallanonaboaranes in molten decaborane affords a number of interesting fused macropolyhedral species (Bould et al., 1999). For example, compound (Ia) gives the mixed cluster fusion products [(PMe3)2IrB26H24Ir(CO)(PMe3)2] and [(CO)(PMe3)2IrB17H20] in low yields. In an attempt to vary these yields and products we have used the chloro-substituted species, (Ib). In the event, however, fusion of an intimate mixture of decaborane(14) and (Ib) at 396 K yielded the second title compound, [2,2,2-(CO)(PMe3)2-nido-2-IrB8H10-4-Cl], (II), as the only isolatable product. A single-crystal X-ray diffraction study was carried out in order to confirm the position of the Cl substituent deduced from NMR spectroscopy (Experimental).
All atoms, including H atoms, were located and freely refined in reasonable positions for (II) (Fig. 2). Additionally, the position of the Cl substituent is confirmed. It differs from the position previously reported for [2,2,2-(CO)(PMe3)2-nido-2-IrB8H10-3-Cl] obtained from the thermolysis of (Ib) in the absence of B10H14 (Bould et al., 1984). The cluster is also similar to the other structurally characterized nido-metallanonaborane species, namely, the third-row rhenaborane [(PMe2Ph)3H2-nido-ReB8H11] (Beckett et al., 1988), in which all H atoms were located except for the terminal and bridging metal hydrides, and the nido-{IrB8} subcluster in the macropolyhedral species [(PMe3)2IrB26H24Ir(CO)(PMe3)2] (Bould et al., 1997).
The position of the Cl substituent in (II) indicates that, during the thermolysis of the arachno-metallaborane precursor compound (Ib) to give (II), the substituent has moved from a B vertex adjacent to the metal atom in the precursor to a position one vertex removed from the metal. In this context, it may be noted that strong heating of a xylene solution of [2,2,2-(CO)(PMe3)2-nido-2-IrB8H10-3-Cl] results in cluster closure, to give the iso-closo species [(PMe3)2HIrB8H7Cl] in which a comparable movement of the Cl to a B vertex remote from the metal centre has been noted (Bould et al., 1982). A mechanism was proposed in which the migration would occur via a cluster diamond-square-diamond rearrangement during the nido → iso-closo step. The low yield in the precursive arachno → nido closure reported here makes the proposal of a reaction mechanism speculative, although it does suggest that the Cl-migration step could also possibly occur prior to the nido → iso-closo closure.