Bis(η⁵-isopropyltetramethylcyclo­pentadienyl)(tetrahydroborato-κ³H,H′,H′′)(tetrahydrofuran-O)-samarium(III): a lanthanidocene complex with a tridentate tetrahydroborato ligand

The lanthanidocene complex [Sm(BH₄)(C₁₂H₁₉)₂(C₄H₈O)], (I), shows a distorted tetrahedral arrangement around the central Sm^III atom. It consists of two η⁵-isopropyltetramethylcyclopentadienyl ligands, one tetrahydroborato (BH₄⁻) ligand bridging via H atoms to the lanthanide atom and one coordinating tetrahydrofuran (thf) molecule. The BH₄⁻ unit of (I) coordinates as a tridentate ligand with three bridging H atoms and one terminal H atom [Sm—B—H4 176 (2)°]. The η⁵-isopropyl­tetra­methylcyclopentadienyl ligands of this bent-sandwich complex [Cp1—Sm—Cp2 133.53 (1)° where Cp denotes the centroid of the cyclopentadienyl ring] adopt staggered conformations.

S1. Comment

In the course of our work on lanthanidocene complexes for homogeneous catalysis (Schumann et al., 1995), we have synthesized compound (I), which represents an example of tridentate ligation by the tetrahydroborato ligand.

The Cp—Sm distances of (I) are 2.4888 (2) and 2.4910 (2) Å, the Sm—O bond length is 2.470 (2) Å and the Sm—B distance is 2.624 (3) Å. Our related work on tetrahydroborato metallocenes (Schumann et al., 1998) revealed that (η⁵-EtMe₄C₅)₂Y(κ²H—BH₄)(thf) contains a bidentate BH₄⁻ ligand with Cp—Y distances of 2.385 (2) and 2.392 (2) Å, a Y—O bond length of 2.389 (2) Å and a Y—B distance of 2.669 (4) Å. The constitution of the Sm^III complex (I) and the constitution of the Y^III complex differ only regarding the metal centre and the substitution of the cyclopentadienyl rings (ⁱPr instead of Et). The Cp—Sm distance of (I) is about 0.1 Å longer than the Cp—Y distance of the Y^III complex, and the Sm—O bond is also 0.081 Å longer than the analogous Y—O bond, due to the larger ionic radius of Sm^III [Sm^III 1.098 Å, Y^III 1.04 Å (Shannon, 1976)]. However, the Sm—B distance [2.624 (3) Å] is 0.045 Å shorter than the Y—B distance [2.669 (4) Å] which is contrary to expectations based on the ionic radii. This can be explained by the observation that the Sm^III complex, (I), has a BH₄⁻ ligand with three bridging hydrogen atoms whereas the Y^III complex contains only two bridging hydrogen atoms. In the case of a tridentate complexation of BH₄⁻, (I), the resulting geometry reduces the Sm—B distance and compensates for the larger ionic radius of Sm^III. Generally, for larger lanthanide atoms tridentate complexation is favored (Lappert et al., 1983). It was observed earlier that an increased number of bridging hydrogen atoms leads to a shorter distance between the two corresponding central atoms (Mayo et al., 1994). In agreement with these results the single-crystal structure of (η⁵-Me₅C₅)₂SmBH₄(thf) (Schumann et al., 1998) with two molecules per asymmetric unit and Sm—B distances of 2.58 (2) and 2.62 (2) Å corresponds to parameters for tridentate ligation; however, in this structure the H atoms of the BH₄⁻ moiety could not be located. Tetrahydroborato lanthanide complexes with the larger Pr^III and Nd^III atoms and the distances Pr—B [2.757 Å] and Nd—B [2.664 Å] were also suggested to have tridentate BH₄⁻ ligation (Deng et al., 1994). These examples show that the variation of the lanthanide centre influences the steric behaviour of lanthanidocene complexes, and there are further examples published in literature (Evans et al., 1999). The geometrical parameters of the three bridging H atoms of (I) indicate that only H2 and H3 are equivalent [B—H2 1.13 (3), B—H3 1.13 (3), Sm—H2 2.51 (3), Sm—H3 2.49 (3) Å, Sm—H2—B 83 (2) and Sm—H3—B 84 (2)°]. The H1 atom is located slightly closer to the Sm atom [B—H1 1.18 (3), Sm—H1 2.36 (3) Å and Sm—H1—B 89 (2)°]. As a result the Sm—B—H4 angle, involving the terminal H4 atom, is 176 (2)°. As expected regarding the bridging H atoms the average Y—H distance of 2.35 Å of the complex (η⁵-EtMe₄C₅)₂Y(κ²H—BH₄)(thf) is shorter than the average Sm—H distance of 2.45 Å of (I).

The average Cp—Sm distances of (η⁵-Me₅C₅)₂SmBH₄(thf) [2.456 (8) Å] and of (η⁵-Me₅C₅)₂SmMe(thf) [2.458 Å] (Evans et al., 1988) are slightly shorter than in (I) [2.490 (2) Å], probably due to the larger cyclopentadienyl ring substituent (isopropyl group) of (I).

S2. Experimental

The synthesis of (I) was conducted by the reaction of samarium trichloride and isopropyl-tetramethylcyclopentadienyl sodium (molar ratio 1:2) refluxing in anhydrous tetrahydrofuran solution for 3 h followed by the addition of one equivalent of NaBH₄ and further refluxing for 3 h yielding 54% of (I). The lanthanidocene complex is air- and moisture-sensitive. Single crystals could be obtained by slow cooling of n-hexane solution to 245 K. ¹H and ¹³C{¹H} NMR spectra were recorded on a Bruker ARX 200.

[C₃H₇(CH₃)₄C₅]₂Sm(κ³H—BH₄)(thf): ¹H NMR (200 MHz, C₆D₆, p.p.m.): δ = 2.27 (m, 2H, CH), 1.96 (s, 12H, CH₃), 0.88 (s, 12H, CH₃), −0.30 (s, 12H, (CH₃)₂), −1.36 (s, 4H, thf), −1.97 (s, 4H, thf), −16.36 (s_br, 4H, BH₄). ¹³C{¹H} NMR (50.32 MHz, C₆D₆, p.p.m.): δ = 123.43 (CC₃H₇), 116.24 (CCH₃), 115.76 (CCH₃), 65.92 (thf), 32.62 (CH(CH₃)₂), 21.47 (thf), 21.17 ((CH₃)₂), 19.17 (CH₃), 18.58 (CH₃).

S3. Refinement

The coverage of the unique data set is 99.9% complete to θ = 30.45°. The structure was solved by direct methods and subsequent difference Fourier syntheses. The peaks for the H atoms of the BH₄⁻ ligand [peak height 0.57 to 0.40 e Å⁻³] were located in the last difference Fourier maps. All hydrogen atoms were refined with isotropic displacement parameters. The Flack parameter was based on 3741 Friedel pairs.

Computing details

Data collection: SMART (Siemens, 1995); cell refinement: SAINT (Siemens, 1995); data reduction: SAINT (Siemens, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1990); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: PLATON99 (Spek, 1990); software used to prepare material for publication: SHELXL97 (Sheldrick, 1997).

Figures

Fig. 1. Molecular structure of (I) showing 40% probability displacement ellipsoids. H atoms are omitted for clarity, except for the BH4^− ligand.

Bis(η⁵-isopropyl-tetramethyl-cyclopentadienyl)- (tetrahydroborato-κ³H,H',H'')-(tetrahydrofuran)-samarium(III)

Crystal data

[Sm(C12H19)2(C4H8O)(BH4)]	Dx = 1.344 Mg m^−3
Mr = 563.84	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, P212121	Cell parameters from 8192 reflections
a = 8.9875 (1) Å	θ = 1.7–30.5°
b = 15.4363 (1) Å	µ = 2.12 mm^−1
c = 20.0845 (2) Å	T = 173 K
V = 2786.40 (5) Å^3	Prismatic, orange
Z = 4	0.42 × 0.26 × 0.18 mm
F(000) = 1172

Data collection

Siemens SMART CCD diffractometer	8462 independent reflections
Radiation source: fine-focus sealed tube	7687 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.057
ω scans	θmax = 30.5°, θmin = 1.7°
Absorption correction: multi-scan (SADABS; Sheldrick, 1996)	h = −12→12
Tmin = 0.507, Tmax = 0.682	k = −22→21
26346 measured reflections	l = −28→25

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: inferred from neighbouring sites
R[F^2 > 2σ(F^2)] = 0.031	All H-atom parameters refined
wR(F^2) = 0.050	w = 1/[σ^2(Fo^2) + (0.002P)^2] where P = (Fo^2 + 2Fc^2)/3
S = 1.01	(Δ/σ)max = 0.064
8462 reflections	Δρmax = 0.52 e Å^−3
480 parameters	Δρmin = −0.90 e Å^−3
0 restraints	Absolute structure: Flack (1983)
Primary atom site location: structure-invariant direct methods	Absolute structure parameter: −0.022 (9)

Special details

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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq
Sm	0.591176 (14)	0.490793 (7)	0.119379 (6)	0.01580 (3)
O	0.7497 (2)	0.40702 (13)	0.19651 (10)	0.0244 (5)
B	0.3770 (4)	0.3769 (2)	0.13404 (19)	0.0247 (8)
H1	0.342 (3)	0.4437 (19)	0.1101 (16)	0.034 (9)*
H2	0.412 (5)	0.4003 (18)	0.1849 (17)	0.034 (9)*
H3	0.478 (4)	0.3440 (19)	0.1125 (18)	0.038 (9)*
H4	0.291 (6)	0.335 (3)	0.137 (3)	0.101 (18)*
C11	0.6543 (3)	0.53055 (19)	−0.01194 (14)	0.0227 (6)
C12	0.7956 (3)	0.5288 (2)	0.02030 (14)	0.0257 (7)
C13	0.8261 (4)	0.4425 (2)	0.03805 (15)	0.0251 (7)
C14	0.7053 (4)	0.3896 (2)	0.01766 (14)	0.0232 (6)
C15	0.5986 (4)	0.44439 (17)	−0.01278 (13)	0.0210 (6)
C16	0.5928 (6)	0.6075 (2)	−0.04966 (18)	0.0372 (8)
H16A	0.654 (5)	0.659 (3)	−0.043 (2)	0.059 (13)*
H16B	0.499 (5)	0.629 (3)	−0.036 (2)	0.058 (15)*
H16C	0.580 (5)	0.592 (2)	−0.0946 (18)	0.043 (10)*
C17	0.9048 (5)	0.6019 (3)	0.0258 (2)	0.0417 (9)
H17A	0.868 (5)	0.652 (3)	−0.001 (2)	0.063 (14)*
H17B	0.987 (5)	0.584 (3)	−0.006 (2)	0.060 (14)*
H17C	0.930 (5)	0.615 (2)	0.0656 (19)	0.035 (10)*
C18	0.9746 (4)	0.4090 (3)	0.0633 (2)	0.0422 (10)
H18A	0.969 (5)	0.357 (3)	0.094 (2)	0.056 (13)*
H18B	1.017 (5)	0.454 (3)	0.090 (2)	0.059 (13)*
H18C	1.040 (4)	0.392 (2)	0.0251 (18)	0.038 (10)*
C19	0.7016 (6)	0.2922 (2)	0.0189 (2)	0.0374 (9)
H19A	0.745 (4)	0.266 (3)	−0.021 (2)	0.052 (12)*
H19B	0.617 (6)	0.269 (3)	0.024 (2)	0.054 (15)*
H19C	0.752 (5)	0.266 (3)	0.054 (2)	0.075 (16)*
C110	0.4592 (4)	0.4090 (2)	−0.04769 (16)	0.0277 (7)
H110	0.425 (4)	0.3602 (19)	−0.0225 (15)	0.032 (9)*
C111	0.5002 (5)	0.3768 (3)	−0.1174 (2)	0.0406 (8)
H11A	0.574 (5)	0.337 (2)	−0.119 (2)	0.065 (13)*
H11B	0.527 (4)	0.423 (2)	−0.1457 (17)	0.030 (9)*
H11C	0.421 (5)	0.346 (2)	−0.1397 (19)	0.052 (11)*
C112	0.3261 (4)	0.4691 (3)	−0.0512 (2)	0.0453 (10)
H11D	0.228 (5)	0.439 (3)	−0.072 (2)	0.058 (13)*
H11E	0.343 (4)	0.510 (2)	−0.0836 (17)	0.037 (10)*
H11F	0.302 (4)	0.494 (3)	−0.0086 (18)	0.056 (11)*
C21	0.4053 (4)	0.58623 (16)	0.20227 (15)	0.0238 (6)
C22	0.4185 (4)	0.63409 (16)	0.14162 (16)	0.0271 (7)
C23	0.5665 (4)	0.66731 (17)	0.13802 (15)	0.0266 (7)
C24	0.6446 (3)	0.63818 (18)	0.19452 (15)	0.0230 (6)
C25	0.5457 (3)	0.58816 (18)	0.23519 (15)	0.0200 (6)
C26	0.2602 (4)	0.5500 (3)	0.2278 (2)	0.0374 (9)
H26A	0.203 (7)	0.567 (3)	0.202 (3)	0.09 (2)*
H26B	0.233 (6)	0.581 (3)	0.267 (2)	0.076 (16)*
H26C	0.259 (5)	0.497 (3)	0.2415 (19)	0.063 (14)*
C27	0.2953 (5)	0.6537 (3)	0.0935 (2)	0.0406 (10)
H27A	0.234 (5)	0.614 (3)	0.090 (2)	0.052 (14)*
H27B	0.325 (5)	0.672 (3)	0.050 (2)	0.069 (15)*
H27C	0.225 (5)	0.684 (3)	0.121 (3)	0.082 (16)*
C28	0.6172 (6)	0.7387 (2)	0.0921 (2)	0.0415 (10)
H28A	0.564 (5)	0.737 (2)	0.053 (2)	0.054 (12)*
H28B	0.727 (5)	0.740 (3)	0.085 (2)	0.052 (13)*
H28C	0.609 (5)	0.792 (2)	0.108 (2)	0.064 (12)*
C29	0.7973 (4)	0.6700 (3)	0.2148 (2)	0.0329 (8)
H29A	0.852 (7)	0.636 (3)	0.233 (3)	0.10 (2)*
H29B	0.786 (5)	0.720 (3)	0.243 (2)	0.047 (12)*
H29C	0.848 (6)	0.684 (3)	0.177 (2)	0.074 (16)*
C210	0.5832 (4)	0.56107 (18)	0.30613 (15)	0.0243 (6)
H210	0.682 (4)	0.5578 (18)	0.3090 (15)	0.018 (8)*
C211	0.5321 (5)	0.6316 (2)	0.35498 (19)	0.0372 (9)
H21A	0.557 (5)	0.616 (2)	0.4032 (19)	0.049 (11)*
H21B	0.409 (5)	0.639 (2)	0.3547 (19)	0.057 (11)*
H21C	0.578 (5)	0.685 (2)	0.3397 (18)	0.052 (11)*
C212	0.5265 (5)	0.4727 (2)	0.32877 (18)	0.0363 (8)
H21D	0.565 (4)	0.455 (2)	0.374 (2)	0.054 (10)*
H21E	0.540 (4)	0.427 (2)	0.2991 (17)	0.026 (10)*
H21F	0.426 (5)	0.470 (2)	0.3389 (16)	0.047 (11)*
C31	0.8839 (4)	0.4385 (2)	0.22942 (18)	0.0284 (7)
H31A	0.852 (5)	0.470 (3)	0.270 (2)	0.067 (14)*
H31B	0.932 (4)	0.472 (2)	0.1979 (16)	0.035 (9)*
C32	0.9720 (4)	0.3586 (2)	0.24839 (19)	0.0334 (8)
H32A	1.029 (4)	0.367 (2)	0.2819 (16)	0.028 (10)*
H32B	1.028 (4)	0.338 (2)	0.2108 (17)	0.035 (10)*
C33	0.8492 (4)	0.2950 (2)	0.26392 (19)	0.0349 (8)
H33A	0.808 (4)	0.308 (2)	0.3067 (19)	0.037 (10)*
H33B	0.874 (4)	0.2402 (19)	0.2640 (15)	0.023 (8)*
C34	0.7322 (5)	0.3146 (2)	0.21113 (19)	0.0312 (8)
H34A	0.754 (4)	0.280 (2)	0.1682 (18)	0.038 (10)*
H34B	0.636 (4)	0.308 (2)	0.2258 (17)	0.034 (10)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Sm	0.01475 (5)	0.01518 (5)	0.01746 (5)	−0.00060 (5)	−0.00117 (6)	0.00073 (5)
O	0.0221 (13)	0.0245 (11)	0.0267 (11)	0.0029 (8)	−0.0035 (9)	0.0016 (8)
B	0.022 (2)	0.0224 (15)	0.029 (2)	−0.0036 (12)	0.0038 (14)	0.0001 (13)
C11	0.0214 (15)	0.0280 (16)	0.0187 (14)	−0.0030 (11)	−0.0002 (11)	0.0034 (11)
C12	0.0209 (15)	0.0374 (18)	0.0188 (14)	−0.0108 (12)	0.0000 (12)	−0.0017 (12)
C13	0.0179 (16)	0.0429 (19)	0.0146 (15)	0.0020 (13)	0.0025 (12)	0.0020 (13)
C14	0.0239 (16)	0.0294 (16)	0.0165 (14)	0.0023 (13)	0.0042 (12)	−0.0027 (12)
C15	0.0182 (14)	0.0297 (14)	0.0150 (13)	−0.0050 (14)	0.0004 (14)	0.0002 (10)
C16	0.052 (2)	0.0314 (17)	0.0278 (18)	−0.004 (2)	−0.007 (2)	0.0088 (13)
C17	0.037 (2)	0.057 (2)	0.032 (2)	−0.026 (2)	0.004 (2)	−0.0055 (17)
C18	0.0240 (19)	0.070 (3)	0.033 (2)	0.0154 (18)	0.0012 (17)	−0.003 (2)
C19	0.053 (3)	0.0265 (19)	0.032 (2)	0.0104 (18)	0.0038 (19)	−0.0052 (15)
C110	0.0255 (16)	0.0382 (18)	0.0193 (16)	−0.0123 (13)	−0.0033 (12)	−0.0003 (13)
C111	0.047 (2)	0.052 (2)	0.0220 (17)	−0.0113 (18)	−0.0034 (19)	−0.0060 (19)
C112	0.0272 (18)	0.074 (3)	0.035 (2)	−0.0030 (18)	−0.0084 (16)	−0.006 (2)
C21	0.0211 (14)	0.0196 (12)	0.0307 (16)	0.0046 (14)	−0.0039 (16)	−0.0050 (10)
C22	0.0269 (17)	0.0206 (12)	0.0338 (17)	0.0071 (14)	−0.0071 (15)	−0.0049 (11)
C23	0.0318 (19)	0.0195 (12)	0.0285 (16)	0.0014 (12)	−0.0019 (13)	−0.0006 (11)
C24	0.0257 (16)	0.0187 (14)	0.0245 (16)	−0.0041 (11)	−0.0049 (12)	−0.0015 (11)
C25	0.0213 (15)	0.0161 (13)	0.0228 (15)	0.0001 (11)	−0.0008 (11)	−0.0029 (11)
C26	0.0228 (19)	0.041 (2)	0.049 (2)	0.0016 (16)	0.0074 (18)	−0.0070 (19)
C27	0.032 (2)	0.043 (2)	0.047 (3)	0.0139 (18)	−0.0139 (18)	−0.0080 (19)
C28	0.063 (3)	0.0235 (16)	0.038 (2)	−0.0033 (18)	−0.007 (2)	0.0090 (14)
C29	0.030 (2)	0.0315 (19)	0.037 (2)	−0.0140 (15)	−0.0057 (17)	−0.0012 (16)
C210	0.0263 (17)	0.0259 (14)	0.0207 (15)	0.0029 (15)	0.0016 (15)	−0.0015 (10)
C211	0.055 (3)	0.0327 (18)	0.0242 (17)	0.0027 (16)	0.0036 (17)	−0.0065 (14)
C212	0.054 (2)	0.0286 (18)	0.0262 (18)	0.0005 (16)	0.0087 (16)	0.0011 (14)
C31	0.0194 (18)	0.0285 (15)	0.0372 (19)	0.0017 (12)	−0.0062 (14)	0.0003 (14)
C32	0.0295 (18)	0.043 (2)	0.0280 (19)	0.0125 (15)	−0.0066 (16)	0.0005 (15)
C33	0.043 (2)	0.0289 (18)	0.033 (2)	0.0079 (15)	−0.0087 (16)	0.0084 (15)
C34	0.034 (2)	0.0233 (16)	0.036 (2)	0.0027 (14)	−0.0053 (17)	−0.0006 (14)

Geometric parameters (Å, º)

Sm—Cp1	2.4888 (2)	C11—C16	1.513 (4)
Sm—Cp2	2.4910 (2)	C12—C13	1.406 (4)
Sm—O	2.470 (2)	C12—C17	1.499 (5)
Sm—B	2.624 (3)	C13—C14	1.419 (4)
Sm—H1	2.36 (3)	C13—C18	1.518 (5)
Sm—H2	2.51 (3)	C14—C15	1.418 (4)
Sm—H3	2.49 (3)	C14—C19	1.503 (5)
B—H1	1.18 (3)	C15—C110	1.536 (4)
B—H2	1.13 (3)	C110—C112	1.515 (5)
B—H3	1.13 (3)	C110—C111	1.530 (5)
B—H4	1.01 (5)	C21—C25	1.425 (5)
Sm—C22	2.739 (3)	C21—C22	1.430 (4)
Sm—C15	2.750 (3)	C21—C26	1.508 (5)
Sm—C23	2.759 (3)	C22—C23	1.428 (5)
Sm—C11	2.767 (3)	C22—C27	1.501 (5)
Sm—C14	2.769 (3)	C23—C24	1.408 (4)
Sm—C12	2.771 (3)	C23—C28	1.508 (5)
Sm—C13	2.771 (3)	C24—C25	1.433 (4)
Sm—C24	2.772 (3)	C24—C29	1.514 (5)
Sm—C21	2.781 (3)	C25—C210	1.523 (4)
Sm—C25	2.799 (3)	C210—C212	1.526 (4)
O—C31	1.459 (4)	C210—C211	1.535 (4)
O—C34	1.465 (4)	C31—C32	1.514 (5)
C11—C15	1.421 (4)	C32—C33	1.510 (5)
C11—C12	1.426 (4)	C33—C34	1.524 (5)
Cp1—Sm—Cp2	133.53 (1)	C12—Sm—C25	125.43 (9)
Cp1—Sm—O	102.45 (5)	C13—Sm—C25	138.20 (9)
Cp2—Sm—O	105.44 (5)	C24—Sm—C25	29.80 (9)
Cp1—Sm—B	109.35 (8)	C21—Sm—C25	29.58 (9)
Cp2—Sm—B	107.01 (8)	C31—O—C34	108.8 (2)
O—Sm—B	90.11 (9)	C31—O—Sm	125.91 (17)
Sm—H1—B	89 (2)	C34—O—Sm	125.01 (19)
Sm—H2—B	83 (2)	C15—C11—C12	107.6 (3)
Sm—H3—B	84 (2)	C15—C11—C16	126.8 (3)
Sm—B—H4	176 (2)	C12—C11—C16	124.6 (3)
H1—B—H2	99 (2)	C15—C11—Sm	74.43 (17)
H1—B—H3	117 (2)	C12—C11—Sm	75.26 (16)
H1—B—H4	112 (3)	C16—C11—Sm	125.2 (2)
H2—B—H3	106 (3)	C13—C12—C11	107.8 (2)
H2—B—H4	111 (4)	C13—C12—C17	124.6 (3)
H3—B—H4	111 (3)	C11—C12—C17	127.0 (3)
O—Sm—C22	130.34 (8)	C13—C12—Sm	75.30 (18)
B—Sm—C22	96.14 (11)	C11—C12—Sm	74.90 (16)
O—Sm—C15	117.06 (8)	C17—C12—Sm	122.7 (2)
B—Sm—C15	87.22 (10)	C12—C13—C14	108.9 (3)
C22—Sm—C15	112.43 (9)	C12—C13—C18	125.3 (3)
O—Sm—C23	118.57 (8)	C14—C13—C18	125.0 (3)
B—Sm—C23	125.98 (10)	C12—C13—Sm	75.30 (19)
C22—Sm—C23	30.10 (10)	C14—C13—Sm	75.08 (17)
C15—Sm—C23	112.96 (8)	C18—C13—Sm	124.3 (2)
O—Sm—C11	126.56 (8)	C15—C14—C13	107.4 (3)
B—Sm—C11	113.96 (10)	C15—C14—C19	126.1 (3)
C22—Sm—C11	95.31 (9)	C13—C14—C19	126.0 (3)
C15—Sm—C11	29.85 (8)	C15—C14—Sm	74.37 (16)
C23—Sm—C11	85.80 (9)	C13—C14—Sm	75.25 (17)
O—Sm—C14	87.34 (8)	C19—C14—Sm	122.9 (2)
B—Sm—C14	88.65 (10)	C14—C15—C11	108.4 (3)
C22—Sm—C14	141.82 (9)	C14—C15—C110	122.4 (3)
C15—Sm—C14	29.77 (9)	C11—C15—C110	128.7 (3)
C23—Sm—C14	133.41 (9)	C14—C15—Sm	75.86 (16)
C11—Sm—C14	49.15 (9)	C11—C15—Sm	75.72 (17)
O—Sm—C12	100.30 (8)	C110—C15—Sm	120.9 (2)
B—Sm—C12	135.15 (10)	C112—C110—C111	110.3 (3)
C22—Sm—C12	108.78 (10)	C112—C110—C15	116.6 (3)
C15—Sm—C12	49.16 (9)	C111—C110—C15	109.7 (3)
C23—Sm—C12	86.66 (9)	C25—C21—C22	108.2 (3)
C11—Sm—C12	29.84 (8)	C25—C21—C26	128.0 (3)
C14—Sm—C12	49.01 (9)	C22—C21—C26	123.5 (3)
O—Sm—C13	77.85 (8)	C25—C21—Sm	75.94 (18)
B—Sm—C13	116.40 (10)	C22—C21—Sm	73.38 (18)
C22—Sm—C13	138.18 (10)	C26—C21—Sm	121.8 (2)
C15—Sm—C13	48.89 (10)	C23—C22—C21	107.8 (3)
C23—Sm—C13	114.02 (10)	C23—C22—C27	125.6 (3)
C11—Sm—C13	48.82 (9)	C21—C22—C27	126.4 (4)
C14—Sm—C13	29.67 (9)	C23—C22—Sm	75.74 (17)
C12—Sm—C13	29.40 (9)	C21—C22—Sm	76.61 (17)
O—Sm—C24	89.34 (8)	C27—C22—Sm	118.4 (2)
B—Sm—C24	128.02 (10)	C24—C23—C22	108.0 (3)
C22—Sm—C24	49.20 (9)	C24—C23—C28	125.1 (3)
C15—Sm—C24	137.31 (8)	C22—C23—C28	125.1 (3)
C23—Sm—C24	29.49 (9)	C24—C23—Sm	75.75 (16)
C11—Sm—C24	107.54 (9)	C22—C23—Sm	74.16 (15)
C14—Sm—C24	143.19 (9)	C28—C23—Sm	127.9 (2)
C12—Sm—C24	95.87 (9)	C23—C24—C25	108.8 (3)
C13—Sm—C24	114.20 (10)	C23—C24—C29	124.5 (3)
O—Sm—C21	104.37 (8)	C25—C24—C29	125.7 (3)
B—Sm—C21	81.21 (10)	C23—C24—Sm	74.76 (16)
C22—Sm—C21	30.01 (9)	C25—C24—Sm	76.16 (16)
C15—Sm—C21	136.93 (10)	C29—C24—Sm	124.7 (2)
C23—Sm—C21	49.25 (9)	C21—C25—C24	107.2 (3)
C11—Sm—C21	125.20 (8)	C21—C25—C210	128.6 (3)
C14—Sm—C21	164.42 (10)	C24—C25—C210	123.0 (3)
C12—Sm—C21	135.73 (9)	C21—C25—Sm	74.48 (17)
C13—Sm—C21	162.37 (10)	C24—C25—Sm	74.04 (17)
C24—Sm—C21	48.95 (10)	C210—C25—Sm	126.71 (18)
O—Sm—C25	81.03 (8)	C25—C210—C212	116.8 (3)
B—Sm—C25	99.18 (10)	C25—C210—C211	109.7 (3)
C22—Sm—C25	49.32 (9)	C212—C210—C211	110.1 (3)
C15—Sm—C25	160.97 (8)	O—C31—C32	106.0 (3)
C23—Sm—C25	49.10 (9)	C33—C32—C31	101.5 (3)
C11—Sm—C25	134.66 (9)	C32—C33—C34	103.4 (3)
C14—Sm—C25	165.95 (9)	O—C34—C33	105.0 (3)