Copyright WILEY-VCH Verlag GmbH, D-69451 Weinheim, 2002.Supporting Information for Angew. Chem. Int. Ed. Z18068

Charge Density Study of Methane-di(triimido)sulfonic AcidCH2{S(NtBu)2(NHtBu)}2

– the NR Analogue of H2C{S(O)2(OH)}2

by

Dirk Leusser, Bernhard Walfort and Dietmar Stalke*

[*]Prof. Dr. D. Stalke, Dipl.-Phys. D. Leusser, Dr. B. Walfort

Institut für Anorganische Chemie der Universität Würzburg

Am Hubland

D-97074 Würzburg

FAX: int. (+49)931-888-4619

E-mail: dstalke@chemie.uni-wuerzburg.de

[**] This work was supported by the Deutsche Forschungsgemeinschaft and the Fonds derChemischen Industrie. The discussions in the Würzburger Graduiertenkolleg Elektronendichtewere very stimulating. We thank one of the referees for valuable comments.

2

Results of a standard conventional refinement (SHELXL[1]) as deposited at the CSD[2]

Fully labelled diagram of H2C{S(NtBu)2(NHtBu)}2. Anisotropic displacement parameters are depicted at

the 50% probability level. Most hydrogen atoms are omitted for clarity.

3

Crystal data and conventional structure refinement for H2C{S(NtBu)2(NHtBu)}2:

Identification code sulfon

Empirical formula C25 H58 N6 S2

Formula weight 506.89

Temperature 100(2) K

Wavelength 0.71073 Å

Crystal system monoclinic

Space group C2/c

Unit cell dimensions a = 29.8239(8) Å α = 90°

b = 11.4206(3) Å β = 91.041(1)°

c = 18.0801(4) Å γ = 90°

Volume 6157.2(3) Å3

Z 8

Density (calculated) 1.094 Mg/m3

Absorption coefficient 0.196 mm-1

F(000) 2256

Crystal size 0.25 x 0.2 x 0.2 mm

Theta range for data collection 1.37 to 52.16°.

Index ranges -66<=h<=66, 0<=k<=25, 0<=l<=40

Reflections collected (low angle batch) 136761

Reflections collected (high angle batch) 217620

Independent reflections (low angle batch) 6629 [R(int) = 0.0435]

Independent reflections (high angle batch) 29791 [R(int) = 0.0646]

Completeness to theta = 52.16° 100.0 %

Refinement method Full-matrix least-squares on F2

Data (used) / restraints / parameters 35375 / 0 / 475

Goodness-of-fit on F2 0.969

Final R indices [I>2sigma(I)] R1 = 0.0315, wR2 = 0.0865

R indices (all data) R1 = 0.0487, wR2 = 0.0932

Largest diff. peak and hole 0.762 and -0.234 e.Å-3

4

Refinement of a starting model for the multipole refinement (SHELXL[1]):

In a first step a high order refinement using 3225 reflections with 0.91Å-1 <sinθ/λ<

1.11Å-1 was performed to obtain the best estimation of positional and thermal

parameters of the non-hydrogen atoms.

Keeping the positional and thermal parameters of the non-hydrogen atoms fixed, the

positions of the hydrogen atoms were determined via difference Fourier synthesis,

using all reflections with sinθ/λ < 0.5 Å-1 and refined using thermal motion constraints:

Uiso(H1/H4/H71/H72) was set 1.2 times the Ueq-value of the bonded non-hydrogen

atom. For all hydrogen atoms which belong to the peripheral methyl groups the Uiso-

value was set to 1.5 times of the corresponding Ueq-value of the bonded carbon

atom. After refinement the hydrogen atoms were shifted along their bonding vector to

neutron diffraction distances[3] of 1.085 Å for the H-C(sp3) and 1.032 Å for the

nitrogen bonded H atom, respectively.

Multipole refinement:

Within the atomic electron density model used in XD[4] the deformation density is

expanded in terms of slater-type radial functions:

( )( )

( )( )( ) rln

lnl

nl r!ln

rR λαα −+

+e

2=

3

.

The coefficients nl of the sulfur atoms were changed to the recommended values

(n1=4, n2=4, n3=6, n4=8)[5] which has been shown a meaningful proceeding especially

for sulfur containing compounds[6, 7].

For all hydrogen atoms energy optimised values were selected.[8] Therefore the

starting values for the expansion/contraction factors were set to 1.2.

A non-crystallographic 2-fold axis through C7 and the centre of S1-C7-S2 was

assumed to reduce the number of parameters to half.

The complexity of the refined model was increased in a stepwise manner. In the first

refinement cycles only the sulfur atoms were refined to fourth order. All other non-

hydrogen atoms were refined to third order, for the hydrogen atoms a bond directed

dipole and quadrupole population was refined, respectively. Equal atom types shared

the same κ-set. After convergence was reached the population parameters of the

5

nitrogen atoms were refined to fourth order as those of the bridging carbon atom. The

model was refined against F2 with a 1/σ2 weighting scheme, using only reflections

with positive intensities and I > 3σ(I) until convergence was reached for the

completed model. Then a refinement with all positive F2 and without any σ(I)-

restrictions was performed.

Chemical constraints and symmetry restrictions:

In addition to the molecular 2-fold axis all C atoms of the methyl groups were

constrained (populations) and refined with local C3 symmetry restrictions along the

C(methyl)-C(tertiary) bond. The bridging carbon atom was refined with the symmetry

restrictions which arise from the local 2-fold axis at C7. Pv and the Plm of all H atoms

of the methyl groups were constrained.

Hydrogen atoms were treated with special care. Coordinates and thermal parameters

were kept fixed on the values of the starting model until coordinates and Uij of the

non-hydrogen atoms were included in the refinement procedure. For all following

steps the hydrogen parameters were adjusted after each step of the refinement using

reflections with sinθ/λ< 0.5 Å-1, keeping the C-H and N-H distances fixed and

restraining the Uiso(H)-values for each methyl group, N1 and N4 and H71 and H72,

respectively.

6

Residual densities after multipole refinement:

Residual densities after multipole refinement. Stepwidth is 0.05 eÅ-3 in contour plots, sinΘ/λmax=1.0Å-1. Positive values solid lines, negative values dashed, zero value dotted. S(1)-N(1)-N(2) plane upperleft plot, N(1)-S(1)-N(2) plane upper right plot, S(1)-C(7)-S(2) plane lower left plot. Isosurface on 0.15eÅ-3 level (lower right). It is obvious that areas with higher residual densities are mostly located in theintermolecular regions.

7

Results from the determination of bond critical points (BCP) as (3,-1) CPs in ρ(r) of

CH2{S(NtBu)2(NHtBu)}2 (only atoms which were refined independently are

displayed):

d (A-B) d (A-BCP) d (BCP-B) ρ(rBCP) ∇ 2ρ(rBCP) εBCP

S1–N1 1.6500 0.7803 0.8697 1.893(20) -13.409(67) 0.11

S1=N2 1.5302 0.7179 0.8123 2.307(27) -16.600(86) 0.10

S1=N3 1.5198 0.7178 0.8021 2.372(28) -16.440(90) 0.06

S1–C7 1.8165 0.9836 0.8330 1.453(12) -8.006(34) 0.09

C7–H71 1.0851 0.7808 0.3044 1.761(7) -18.067(19) 0.05

N1–C1 1.4984 0.8479 0.6505 1.767(6) -10.237(17) 0.02

N2–C2 1.4908 0.8319 0.6589 1.853(6) -11.089(16) 0.06

N3–C3 1.4749 0.8318 0.6431 1.852(6) -10.622(17) 0.04

N1–H1 1.0320 0.8435 0.1885 1.892(6) -29.062(14) 0.05

C1–C11 1.5286 0.7848 0.7438 1.761(4) -12.163(8) 0.03

C11–H11 1.0850 0.7477 0.3373 1.740(2) -14.617(4) 0.03

H1...N5 2.1702 0.8069 1.3633 0.131 1.87 0.14

H4...N2 2.1440 0.7925 1.3515 0.137 1.95 0.13

d(A-B): distance between atoms A and B along the bondpath in Å; d(A-BCP), d(BCP-B): distancebetween BCP and atom A and B, respectively; ρ(rBCP): charge density at the BCP in eÅ-3; ∇ 2ρ(rBCP):Laplacian of ρ(r) at the BCP in eÅ-5; εBCP: ellipticity of ρ(r) at the BCP.

8

Geometrical features of the non bonding valence shell charge

concentrations (VSCC) at the nitrogen atoms (labled LP) as

determined via a (3,-3) critical point search in -∇ 2ρ :

C1-N1-S1 = 127.1°C1-N1-H1 = 112.3°S1-N1-H1 = 104.6°

LP1-N1-S1 = 87.0°LP1-N1-C1 = 105.3°LP1-N1-H1 = 119.2°

Angle between the normal vectorof the LP1-N1-H1 plane and theS1-N1 bonding vector = 105.4°C1-N1 bonding vector = 129.7°

H(1)

N1-LP1 = 0.41 Å

N1-S1 = 1.649 ÅN1-C1 = 1.498 ÅN1-H1 = 1.032 Å

N2-LP2A = 0.41 ÅN2-LP2B = 0.41 Å

N2-S1 = 1.528 ÅN2-C2 = 1.489 Å

C2-N2-S1 = 123.3°

LP2A-N2-LP2B = 62.8°

LP2A-N2-C2 = 123.8°LP2B-N2-C2 = 133.7°

LP2A-N2-S1 = 98.4°LP2B-N2-S1 = 97.0°

Angle between the normal vector of theLP2A-N2-LP2B plane and theS1-N2 bonding vector = 99.1°C2-N2 bonding vector = 137.9°

9

C3-N3-S1 = 126.6°

LP3A-N3-LP3B = 102.2°

LP3A-N3-C3 = 114.1°LP3B-N3-C3 = 109.9°

LP3A-N3-S1 = 98.2°LP3B-N3-S1 = 102.8

Angle between the normal vector of theLP3A-N3-LP2B plane and theS1-N3 bonding vector = 107.1°C3-N3 bonding vector = 126.8°

H(71)

N3-LP3A,B = 0.41 Å

N3-C3 = 1.473 ÅN3-S1 = 1.518 Å

H(72)

H(4)

H(1)

N1-H1-N5 = 142.7°N2-H4-N4 = 142.8°

LP2A-N2-LP2B = 62.8°

N2-LP2A-H4 = 158.4°N2-LP2B-H4 = 118.4°

H1-N5 = 2.157 ÅH4-N2 = 2.138 ÅLP2A-H4 = 1.751 ÅLP2B-H4 = 1.912 Å

10Laplacian distribution in CH2{S(NtBu)2(NHtBu)}2:

Upper row: Isosurface maps at constant -∇ 2ρ(r) values indicating bonded and non-bonded charge concentrations around S1, N1, N2 and N3 (-∇ 2ρ(r) = 13 eÅ-5 forS1, 47 eÅ-5 for N1, 48 eÅ-5 for N2 and 46 eÅ-5 for N3, respectively).2nd and 3rd row: Contour plots of charge concentrations in the C7–S1–N1 plane, H1–N1–LP1 plane, LP2A–N2–LP2B plane, LP3A–N3–LP3B plane, N3–S1–N2plane, S1–N1–C1 plane, S1–N2–C2 plane and the S1–N3–C3 plane (from upper left to lower right). Non-bonding VSCCs (lone pairs) are labled LP. Positivevalues of ∇ 2ρ(r) are marked by dashed lines, negative values by solid lines.

11

Distribution of the static deformation density of the S2(NH)2N4CH2 unit at the 0.3 e/Å3

level:

N6

N5

N4

N3

N2

N1

S1S2 C7

H4

H1

12

References:

[1] G. M. Sheldrick, SHELXL-97, Program for Crystal Structure Refinement,

University of Göttingen, 1997.

[2] CCDC-no. 171901.

[3] F. Allen, Acta Cryst. Sect. B 1986, 42, 512.

[4] Koritsanszky, S. Howard, T. Richter, Z. W. Su, P. R. Mallinson, N. K. Hansen, XD

– A Computer Program Package for Multipole Refinement and Analysis of Electron

Densities from Diffraction Data. User Manual, Freie Universität Berlin, 1995.

[5] N. K. Hansen, P. Coppens, Acta Cryst. Sect. A 1978, 34, 909.

[6] E. Espinosa, E. Molins, C. Lecomte, Phys. Rev. Sect. B 1997, 56, 1820.

[7] S. Pillet, M. Souhassou, Y. Pontillon, A. Caneschi, D. Gatteschi, C. Lecomte, New

J. Chem. 2001, 25, 131-143.

[8] E. Clementi, C. Roetti, At. Data Nucl. Data Tables 1974, 14, 177.