organic compounds
1,1′-(Diselanediylbis{[P,P-diphenyl-N-(trimethylsilyl)phosphorimidoyl]methanylylidene})bis[1,1-diphenyl-N-(trimethylsilyl)-λ5-phosphanamine] pentane disolvate
aDepartment of Chemistry, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada, and bDepartment of Chemistry, PO Box 3000, University of Oulu, 90014 Oulu, Finland
*Correspondence e-mail: risto.laitinen@oulu.fi
The title compound, C62H78N4P4Se2Si4·2C5H12, is made up of two [SeC(PPh2NSiMe3)(PPh2NHSiMe3)] units related by an inversion center situated at the mid-point of the diselenide bond. It crystallized with two disordered molecules of pentane used as solvent of crystallization. It is a rare example of an antiperiplanar diselenide and exhibits a long Se—Se bond of 2.4717 (8) Å. The Se—C bond length of 1.876 (5) Å is short in comparison with the range of values found for other diselenides (1.91–1.97 Å). The molecule exhibits two intramolecular N—H⋯N hydrogen bonds. In the crystal, there are no significant intermolecular interactions present. One of the Me3Si– groups is disordered over two positions with a refined occupancy ratio of 0.708 (8):0.292 (8). The contribution of the disordered solvent to the scattering was removed with the SQUEEZE option of PLATON [Spek (2009). Acta Cryst. D65, 148–155]. The solvent contribution has been included in the reported molecular weight and density.
CCDC reference: 974699
Related literature
For the coordination chemistry of diselenides, see: Risto et al. (2011). For examples of antiperiplanar diselenides, see: Wagner et al. (1990); Dhau et al. (2011). For geometric parameters in organic diselenides, see: Dickson et al. (1999); Steudel et al. (1980); Schmidbaur et al. (1983); Konu et al. (2010); Back & Codding (1983); Pyykkö & Atsumi (2009). For the binding energies of organic dislenides, see; McDonough et al. (2005). For the synthesis of the reagent {Li2[C(PPh2NSiMe3)2]}, see: Kasani et al. (1999).
Experimental
Crystal data
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Data collection: COLLECT (Nonius, 1999); cell DENZO (Otwinowski & Minor, 1997); data reduction: SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Putz & Brandenburg, 2013); software used to prepare material for publication: WinGX (Farrugia, 2012).
Supporting information
CCDC reference: 974699
https://doi.org/10.1107/S1600536813032674/su2665sup1.cif
contains datablocks global, I. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S1600536813032674/su2665Isup2.hkl
The reagent {Li2[C(PPh2NSiMe3)2]} (I), was prepared according to the literature procedure (Kasani et al., 1999). A mixture of (I) (0.254 g, 0.445 mmol) and SeCl4 (0.098 g, 0.445 mmol) was placed in a 50 ml round-bottomed flask under an argon atmosphere using standard Schlenk techniques. Pentane (10 ml) was added drop-wise over a period of 15 min. at 195 K. The solution was then allowed to reach room temperature and stirred for a further 8 h after which it was filtered, to remove LiCl, and gave an orange solution. The 31P NMR spectrum of the filtrate (400 MHz, pentane, 298 K) revealed a complex mixture of products with resonances at δ 4.99 (s), 1.14(s), 3.87(s), 5.40 (d, J = 5.0 Hz), 7.83(d, J = 5.0 Hz), 10.23(s), and 18.51(s). The filtrate was allowed to evaporate slowly at room temperature under an argon atmosphere to produce a few red crystals of the title compound after 45 days. Further details of the synthetic procedure are available in the archived CIF.
The hydrogen atom bound to atom N2 was located in the difference Fourier map and refined with Uiso(H) = 0.05 Å2. All C-bound H atoms were placed in idealized positions and treated as riding atoms: C-H = 0.95 and 0.98 Å for CH and CH3 H atoms, respectively, with Uiso(H) = 1.5Ueq(C-methyl) and = 1.2Ueq(C) for other H atoms. The Me3Si group involving Si2 is disordered with two alternative orientations, atoms C30/C31:C32/C33 with a refined occupany ratio of 0.708 (8):0.298 (8), and their anisotropic displacement parameters were made equal. The disordered solvent pentane molecules could not be refined satisfactorily and were excluded using the SQUEEZE routine in PLATON (Spek, 2009); solvent-accessible void space of 249 Å3 corresponding to 85 electron count/cell. This is equivalent to two pentane solvent molecules (84 electrons) per unit cell.
Organic diselenides are of interest from the viewpoint of coordination chemistry (Risto et al., 2011) as well as for their structural aspects. The C—Se—Se—C torsion angle typically falls within a wide range of ca. 73–128° (Dickson et al., 1999). The only examples of antiperiplanar diselenides (C—Se—Se—C = 180°) involve very bulky R groups, for example, (Me3Si)3CSeSeC(SiMe3)3 (d(Se—Se) = 2.388 (1) Å) (Wagner et al., 1990), or intramolecular heteroatom coordination to the Se centers as in bis(3,5-dimethyl-2-pyridyl)diselenide (d(Se—Se) = 2.352 (2) Å) (Dhau et al., 2011). In this work we unexpectedly isolated a small amount of the title diselenide as red crystals from the reaction of {Li2[C(PPh2NSiMe3)2]} with SeCl4 (1:1 molar ratio) in pentane.
The
analysis of the title compound revealed a centrosymmetric dimer in which a diselenido (–Se—Se-) unit bridges two monoprotonated units (Fig. 1). The torsion angle C25—Se—Sei—C25i is 180 °, as a result of the inversion centre, and the two anionic ligands are in a trans orientation with respect to –Se—Se- bridge. The Se—Se bond length of 2.4717 (8) Å is substantially longer than those in typical diaryl diselenides (range 2.29–2.35 Å) [Dickson et al., 1999]. At the same time the Se—C bond of 1.876 (5) Å is short in comparison with the range of values found for other diselenides (1.91–1.97 Å) (Back & Codding, 1983) and the calculated value of 1.91 Å (Pyykkö & Atsumi, 2009). This bonding arrangement is reminiscent of the alternation of the S—S bond lengths in cycloheptasulfur, which has been rationalized in terms of p lone pair repulsions of the neighbouring sulfur atoms due to the torsion angle of 0° and (Steudel et al., 1980). We also note that the Se—Se bond lengths of 2.492 (2) Å found for the dication [(Ph3P)2CSe-SeC(PPh3)2]2+ (Schmidbaur et al., 1983) and 2.508 (1) Å exhibited by the dilithium complex {[Li(TMEDA)]2[(SPh2P)2CSe-SeC(PPh2S)2]} (Konu et al., 2010) are comparable to that of the title compound. In the latter case, the Se—Se bonding interaction is due solely to the poor overlap of the SOMOs of the anion radicals. Consequently the calculated binding energy is small (90 kJ mol-1) compared to typical values for organic diselenides, e.g. 172 kJ mol-1 for PhSe-SePh (McDonough et al., 2005). The Se—C distance of 1.885 (3) Å in [{Li(TMEDA)}2{(SPh2P)2CSe-SeC(PPh2S)2}] (Konu et al., 2010) is also comparable with that in the title compound.The protonation of one of the nitrogen atoms, N1, is evident from the disparity of ca 0.07 Å in the P—N bond lengths, and smaller differences in the Si—N and P—C(Se) distances of 0.038 Å and 0.036 Å, respectively. Intramolecular hydrogen bonding between the N—H functionality and two-coordinate nitrogen atom (1.981 (15) Å) is observed (Table 1). The geometry at the three-coordinate carbon atom is almost planar (Σ<C(25) = 356.1°).
In the crystal, there are no significant intermolecular interactions present.
For the coordination chemistry of diselenides, see: Risto et al. (2011). For examples of antiperiplanar diselenides, see: Wagner et al. (1990); Dhau et al. (2011). For geometric parameters in organic diselenides, see: Dickson et al. (1999); Steudel et al. (1980); Schmidbaur et al. (1983); Konu et al. (2010); Back & Codding (1983); Pyykkö & Atsumi (2009). For the binding energies of organic dislenides, see; McDonough et al. (2005). For the synthesis of the reagent {Li2[C(PPh2NSiMe3)2]}, see: Kasani et al. (1999).
Data collection: COLLECT (Nonius, 1999); cell
DENZO (Otwinowski & Minor, 1997); data reduction: SCALEPACK (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Putz & Brandenburg, 2013); software used to prepare material for publication: WinGX (Farrugia, 2012).C62H78N4P4Se2Si4·2C5H12 | Z = 1 |
Mr = 1417.74 | F(000) = 746 |
Triclinic, P1 | Dx = 1.314 Mg m−3 |
Hall symbol: -P 1 | Mo Kα radiation, λ = 0.71073 Å |
a = 10.2500 (3) Å | Cell parameters from 6257 reflections |
b = 13.4420 (3) Å | θ = 1.7–25.0° |
c = 14.6670 (4) Å | µ = 1.23 mm−1 |
α = 65.611 (1)° | T = 173 K |
β = 85.525 (1)° | Block, red |
γ = 76.730 (2)° | 0.22 × 0.15 × 0.09 mm |
V = 1791.03 (8) Å3 |
Nonius KappaCCD FR540C diffractometer | 4902 reflections with I > 2σ(I) |
Horizonally mounted graphite crystal monochromator | Rint = 0.064 |
φ scans, and ω scans with κ offsets | θmax = 25.0°, θmin = 1.7° |
Absorption correction: multi-scan (SORTAV; Blessing, 1997) | h = −12→12 |
Tmin = 0.773, Tmax = 0.897 | k = −15→15 |
11811 measured reflections | l = −17→17 |
6257 independent 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)] = 0.068 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.170 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.04 | w = 1/[σ2(Fo2) + (0.0591P)2 + 10.1653P] where P = (Fo2 + 2Fc2)/3 |
6257 reflections | (Δ/σ)max < 0.001 |
345 parameters | Δρmax = 0.77 e Å−3 |
0 restraints | Δρmin = −0.71 e Å−3 |
C62H78N4P4Se2Si4·2C5H12 | γ = 76.730 (2)° |
Mr = 1417.74 | V = 1791.03 (8) Å3 |
Triclinic, P1 | Z = 1 |
a = 10.2500 (3) Å | Mo Kα radiation |
b = 13.4420 (3) Å | µ = 1.23 mm−1 |
c = 14.6670 (4) Å | T = 173 K |
α = 65.611 (1)° | 0.22 × 0.15 × 0.09 mm |
β = 85.525 (1)° |
Nonius KappaCCD FR540C diffractometer | 6257 independent reflections |
Absorption correction: multi-scan (SORTAV; Blessing, 1997) | 4902 reflections with I > 2σ(I) |
Tmin = 0.773, Tmax = 0.897 | Rint = 0.064 |
11811 measured reflections |
R[F2 > 2σ(F2)] = 0.068 | 0 restraints |
wR(F2) = 0.170 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.04 | w = 1/[σ2(Fo2) + (0.0591P)2 + 10.1653P] where P = (Fo2 + 2Fc2)/3 |
6257 reflections | Δρmax = 0.77 e Å−3 |
345 parameters | Δρmin = −0.71 e Å−3 |
Experimental. Some details of the procedure for the synthesis of the title compound: Solvents were dried over and distilled from Na/benzophenone (toluene). t–BuLi (1.7 M in pentane), CH2(PPh2)2, and azidotrimethylsilane were purchased from Aldrich Chemical Co. and were used without further purification. 31P NMR spectra were recorded on Bruker 400 NMR spectrometers. 31P NMR chemical shifts were referenced externally to 85% H3PO4 (0 p.p.m.). |
Geometry. Bond distances, angles etc. have been calculated using the rounded fractional coordinates. All su's are estimated from the variances of the (full) variance-covariance matrix. The cell esds are taken into account in the estimation of distances, angles and torsion angles |
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. |
x | y | z | Uiso*/Ueq | Occ. (<1) | |
Se1 | 0.62199 (5) | 0.46193 (4) | 0.01409 (4) | 0.0187 (2) | |
P1 | 0.66004 (14) | 0.20765 (11) | 0.15809 (10) | 0.0169 (4) | |
P2 | 0.68890 (14) | 0.37513 (11) | 0.23793 (10) | 0.0176 (4) | |
Si1 | 0.82048 (16) | −0.00542 (12) | 0.31167 (12) | 0.0221 (5) | |
Si2 | 0.6027 (2) | 0.28692 (16) | 0.46105 (14) | 0.0448 (7) | |
N1 | 0.7173 (4) | 0.1237 (4) | 0.2656 (3) | 0.0196 (12) | |
N2 | 0.6632 (5) | 0.2815 (4) | 0.3492 (3) | 0.0204 (14) | |
C1 | 0.5008 (5) | 0.1850 (4) | 0.1340 (4) | 0.0174 (16) | |
C2 | 0.4386 (6) | 0.1116 (5) | 0.2129 (5) | 0.0289 (17) | |
C3 | 0.3148 (6) | 0.0946 (5) | 0.1980 (5) | 0.036 (2) | |
C4 | 0.2537 (6) | 0.1490 (5) | 0.1036 (5) | 0.0300 (19) | |
C5 | 0.3150 (6) | 0.2206 (5) | 0.0253 (4) | 0.0260 (17) | |
C6 | 0.4372 (5) | 0.2381 (4) | 0.0400 (4) | 0.0213 (17) | |
C7 | 0.7647 (5) | 0.1909 (4) | 0.0565 (4) | 0.0202 (17) | |
C8 | 0.7466 (6) | 0.1186 (5) | 0.0134 (4) | 0.0250 (17) | |
C9 | 0.8349 (6) | 0.1011 (5) | −0.0570 (5) | 0.031 (2) | |
C10 | 0.9398 (6) | 0.1555 (5) | −0.0885 (5) | 0.0330 (19) | |
C11 | 0.9581 (6) | 0.2261 (5) | −0.0477 (5) | 0.0297 (17) | |
C12 | 0.8732 (6) | 0.2440 (5) | 0.0255 (4) | 0.0246 (17) | |
C13 | 0.8667 (5) | 0.3776 (5) | 0.2288 (4) | 0.0205 (17) | |
C14 | 0.9151 (6) | 0.4578 (5) | 0.1462 (4) | 0.0257 (17) | |
C15 | 1.0513 (6) | 0.4514 (5) | 0.1330 (5) | 0.0289 (17) | |
C16 | 1.1417 (6) | 0.3631 (5) | 0.2016 (5) | 0.034 (2) | |
C17 | 1.0965 (6) | 0.2834 (5) | 0.2835 (5) | 0.0364 (19) | |
C18 | 0.9581 (6) | 0.2898 (5) | 0.2983 (4) | 0.0254 (17) | |
C19 | 0.5998 (6) | 0.5112 (4) | 0.2292 (4) | 0.0211 (17) | |
C20 | 0.6627 (7) | 0.5828 (5) | 0.2472 (5) | 0.031 (2) | |
C21 | 0.5886 (7) | 0.6841 (5) | 0.2453 (5) | 0.0321 (19) | |
C22 | 0.4515 (7) | 0.7124 (5) | 0.2264 (5) | 0.0372 (19) | |
C23 | 0.3872 (7) | 0.6421 (5) | 0.2097 (4) | 0.0305 (19) | |
C24 | 0.4621 (6) | 0.5401 (4) | 0.2121 (4) | 0.0234 (17) | |
C25 | 0.6376 (5) | 0.3468 (4) | 0.1432 (4) | 0.0189 (17) | |
C26 | 0.9939 (6) | −0.0041 (5) | 0.2624 (5) | 0.0345 (19) | |
C27 | 0.7579 (7) | −0.1112 (5) | 0.2845 (5) | 0.037 (2) | |
C28 | 0.8339 (8) | −0.0567 (6) | 0.4512 (5) | 0.046 (3) | |
C29 | 0.6230 (9) | 0.1439 (7) | 0.5524 (6) | 0.061 (2) | |
C30 | 0.7320 (13) | 0.3449 (10) | 0.5058 (8) | 0.061 (2) | 0.708 (8) |
C31 | 0.4399 (13) | 0.3696 (10) | 0.4602 (8) | 0.061 (2) | 0.708 (8) |
C32 | 0.581 (3) | 0.409 (2) | 0.4776 (19) | 0.061 (2) | 0.292 (8) |
C33 | 0.394 (3) | 0.287 (3) | 0.4303 (19) | 0.061 (2) | 0.292 (8) |
H2 | 0.48110 | 0.07320 | 0.27700 | 0.0350* | |
H5 | 0.27280 | 0.25790 | −0.03900 | 0.0310* | |
H6 | 0.47900 | 0.28730 | −0.01470 | 0.0250* | |
H8 | 0.67370 | 0.08190 | 0.03300 | 0.0300* | |
H9 | 0.82340 | 0.05080 | −0.08440 | 0.0380* | |
H10 | 0.99870 | 0.14390 | −0.13820 | 0.0390* | |
H3 | 0.27200 | 0.04580 | 0.25220 | 0.0430* | |
H4 | 0.16950 | 0.13670 | 0.09320 | 0.0360* | |
H14 | 0.85370 | 0.51740 | 0.09850 | 0.0310* | |
H15 | 1.08310 | 0.50720 | 0.07720 | 0.0350* | |
H16 | 1.23530 | 0.35780 | 0.19160 | 0.0410* | |
H17 | 1.15890 | 0.22370 | 0.33030 | 0.0430* | |
H18 | 0.92690 | 0.23490 | 0.35520 | 0.0300* | |
H20 | 0.75650 | 0.56240 | 0.26080 | 0.0370* | |
H21 | 0.63140 | 0.73360 | 0.25680 | 0.0390* | |
H22 | 0.40100 | 0.78180 | 0.22480 | 0.0440* | |
H23 | 0.29330 | 0.66250 | 0.19690 | 0.0360* | |
H24 | 0.41850 | 0.49020 | 0.20180 | 0.0280* | |
H26A | 0.99130 | 0.01940 | 0.18970 | 0.0520* | |
H26B | 1.05060 | −0.07940 | 0.29370 | 0.0520* | |
H26C | 1.03080 | 0.04830 | 0.27800 | 0.0520* | |
H27A | 0.66800 | −0.11570 | 0.31160 | 0.0550* | |
H27B | 0.81870 | −0.18460 | 0.31560 | 0.0550* | |
H27C | 0.75430 | −0.08860 | 0.21190 | 0.0550* | |
H28A | 0.86960 | −0.00440 | 0.46780 | 0.0700* | |
H28B | 0.89420 | −0.13080 | 0.47860 | 0.0700* | |
H28C | 0.74490 | −0.06180 | 0.48010 | 0.0700* | |
H29A | 0.71770 | 0.10600 | 0.55770 | 0.0920* | |
H29B | 0.56960 | 0.10490 | 0.53140 | 0.0920* | |
H29C | 0.59250 | 0.14320 | 0.61770 | 0.0920* | |
H30A | 0.81700 | 0.28940 | 0.52440 | 0.0920* | 0.708 (8) |
H30B | 0.69690 | 0.36000 | 0.56400 | 0.0920* | 0.708 (8) |
H30C | 0.74680 | 0.41430 | 0.45150 | 0.0920* | 0.708 (8) |
H31A | 0.38760 | 0.32550 | 0.51430 | 0.0920* | 0.708 (8) |
H31B | 0.39500 | 0.39310 | 0.39580 | 0.0920* | 0.708 (8) |
H31C | 0.44750 | 0.43590 | 0.47010 | 0.0920* | 0.708 (8) |
H2N | 0.667 (7) | 0.215 (6) | 0.335 (5) | 0.0500* | |
H11 | 1.03010 | 0.26360 | −0.06960 | 0.0360* | |
H12 | 0.88870 | 0.29190 | 0.05440 | 0.0290* | |
H32A | 0.50750 | 0.46490 | 0.43410 | 0.0920* | 0.292 (8) |
H32B | 0.66390 | 0.43720 | 0.46040 | 0.0920* | 0.292 (8) |
H32C | 0.56000 | 0.39470 | 0.54760 | 0.0920* | 0.292 (8) |
H33A | 0.35630 | 0.23870 | 0.49180 | 0.0920* | 0.292 (8) |
H33B | 0.39460 | 0.25770 | 0.37880 | 0.0920* | 0.292 (8) |
H33C | 0.33990 | 0.36310 | 0.40660 | 0.0920* | 0.292 (8) |
U11 | U22 | U33 | U12 | U13 | U23 | |
Se1 | 0.0189 (3) | 0.0179 (3) | 0.0156 (3) | −0.0032 (2) | −0.0016 (2) | −0.0033 (2) |
P1 | 0.0168 (7) | 0.0161 (7) | 0.0175 (7) | −0.0032 (6) | −0.0008 (6) | −0.0066 (6) |
P2 | 0.0211 (7) | 0.0178 (7) | 0.0139 (7) | −0.0054 (6) | −0.0003 (6) | −0.0058 (6) |
Si1 | 0.0204 (8) | 0.0171 (8) | 0.0240 (8) | −0.0023 (6) | −0.0017 (7) | −0.0043 (6) |
Si2 | 0.0679 (15) | 0.0298 (10) | 0.0244 (10) | −0.0030 (10) | 0.0196 (10) | −0.0063 (8) |
N1 | 0.020 (2) | 0.018 (2) | 0.020 (2) | −0.0059 (19) | 0.0012 (19) | −0.0063 (19) |
N2 | 0.027 (3) | 0.022 (2) | 0.013 (2) | −0.009 (2) | 0.0041 (19) | −0.0068 (19) |
C1 | 0.015 (3) | 0.012 (2) | 0.022 (3) | 0.000 (2) | −0.001 (2) | −0.005 (2) |
C2 | 0.024 (3) | 0.028 (3) | 0.029 (3) | −0.005 (3) | −0.002 (3) | −0.006 (3) |
C3 | 0.023 (3) | 0.035 (4) | 0.042 (4) | −0.013 (3) | 0.001 (3) | −0.005 (3) |
C4 | 0.018 (3) | 0.028 (3) | 0.040 (4) | −0.008 (3) | −0.007 (3) | −0.007 (3) |
C5 | 0.020 (3) | 0.025 (3) | 0.026 (3) | −0.002 (2) | −0.005 (2) | −0.004 (3) |
C6 | 0.020 (3) | 0.020 (3) | 0.023 (3) | −0.006 (2) | 0.001 (2) | −0.007 (2) |
C7 | 0.016 (3) | 0.017 (3) | 0.021 (3) | 0.002 (2) | −0.006 (2) | −0.003 (2) |
C8 | 0.022 (3) | 0.023 (3) | 0.029 (3) | −0.002 (2) | 0.000 (3) | −0.011 (3) |
C9 | 0.035 (4) | 0.029 (3) | 0.035 (4) | 0.001 (3) | 0.001 (3) | −0.022 (3) |
C10 | 0.025 (3) | 0.033 (3) | 0.037 (4) | 0.007 (3) | 0.005 (3) | −0.018 (3) |
C11 | 0.017 (3) | 0.031 (3) | 0.031 (3) | 0.000 (3) | 0.004 (3) | −0.006 (3) |
C12 | 0.019 (3) | 0.023 (3) | 0.028 (3) | −0.002 (2) | −0.005 (2) | −0.007 (2) |
C13 | 0.022 (3) | 0.023 (3) | 0.019 (3) | −0.006 (2) | −0.002 (2) | −0.010 (2) |
C14 | 0.025 (3) | 0.023 (3) | 0.025 (3) | −0.005 (2) | −0.005 (3) | −0.005 (2) |
C15 | 0.030 (3) | 0.031 (3) | 0.028 (3) | −0.014 (3) | 0.003 (3) | −0.011 (3) |
C16 | 0.025 (3) | 0.045 (4) | 0.037 (4) | −0.018 (3) | 0.009 (3) | −0.018 (3) |
C17 | 0.028 (3) | 0.032 (3) | 0.039 (4) | −0.001 (3) | −0.002 (3) | −0.007 (3) |
C18 | 0.020 (3) | 0.029 (3) | 0.025 (3) | −0.005 (3) | −0.005 (2) | −0.008 (3) |
C19 | 0.027 (3) | 0.021 (3) | 0.014 (3) | −0.001 (2) | 0.000 (2) | −0.008 (2) |
C20 | 0.038 (4) | 0.028 (3) | 0.031 (4) | −0.011 (3) | −0.001 (3) | −0.014 (3) |
C21 | 0.043 (4) | 0.031 (3) | 0.030 (3) | −0.016 (3) | 0.002 (3) | −0.016 (3) |
C22 | 0.055 (4) | 0.022 (3) | 0.025 (3) | 0.005 (3) | 0.000 (3) | −0.007 (3) |
C23 | 0.036 (4) | 0.031 (3) | 0.022 (3) | −0.001 (3) | −0.008 (3) | −0.010 (3) |
C24 | 0.035 (3) | 0.018 (3) | 0.012 (3) | −0.004 (2) | 0.000 (2) | −0.002 (2) |
C25 | 0.018 (3) | 0.018 (3) | 0.016 (3) | −0.002 (2) | −0.002 (2) | −0.003 (2) |
C26 | 0.020 (3) | 0.031 (3) | 0.048 (4) | −0.002 (3) | 0.004 (3) | −0.014 (3) |
C27 | 0.034 (4) | 0.021 (3) | 0.053 (4) | −0.004 (3) | 0.000 (3) | −0.014 (3) |
C28 | 0.051 (5) | 0.041 (4) | 0.034 (4) | 0.010 (3) | −0.010 (3) | −0.011 (3) |
C29 | 0.073 (4) | 0.066 (4) | 0.027 (3) | −0.004 (3) | 0.011 (3) | −0.009 (3) |
C30 | 0.073 (4) | 0.066 (4) | 0.027 (3) | −0.004 (3) | 0.011 (3) | −0.009 (3) |
C31 | 0.073 (4) | 0.066 (4) | 0.027 (3) | −0.004 (3) | 0.011 (3) | −0.009 (3) |
C32 | 0.073 (4) | 0.066 (4) | 0.027 (3) | −0.004 (3) | 0.011 (3) | −0.009 (3) |
C33 | 0.073 (4) | 0.066 (4) | 0.027 (3) | −0.004 (3) | 0.011 (3) | −0.009 (3) |
Se1—C25 | 1.876 (5) | C2—H2 | 0.9500 |
Se1—Se1i | 2.4717 (8) | C3—H3 | 0.9500 |
P1—N1 | 1.573 (4) | C4—H4 | 0.9500 |
P1—C1 | 1.814 (6) | C5—H5 | 0.9500 |
P1—C7 | 1.827 (6) | C6—H6 | 0.9500 |
P1—C25 | 1.753 (6) | C8—H8 | 0.9500 |
P2—N2 | 1.645 (5) | C9—H9 | 0.9500 |
P2—C13 | 1.824 (6) | C10—H10 | 0.9500 |
P2—C19 | 1.804 (6) | C11—H11 | 0.9500 |
P2—C25 | 1.731 (6) | C12—H12 | 0.9500 |
Si1—N1 | 1.699 (5) | C14—H14 | 0.9500 |
Si1—C26 | 1.867 (7) | C15—H15 | 0.9500 |
Si1—C27 | 1.876 (7) | C16—H16 | 0.9500 |
Si1—C28 | 1.876 (7) | C17—H17 | 0.9500 |
Si2—N2 | 1.732 (5) | C18—H18 | 0.9500 |
Si2—C29 | 1.808 (9) | C20—H20 | 0.9500 |
Si2—C30 | 1.956 (14) | C21—H21 | 0.9500 |
Si2—C31 | 1.778 (14) | C22—H22 | 0.9500 |
Si2—C32 | 1.72 (3) | C23—H23 | 0.9500 |
Si2—C33 | 2.22 (3) | C24—H24 | 0.9500 |
N2—H2N | 0.99 (8) | C26—H26A | 0.9800 |
C1—C2 | 1.396 (9) | C26—H26B | 0.9800 |
C1—C6 | 1.396 (8) | C26—H26C | 0.9800 |
C2—C3 | 1.389 (9) | C27—H27A | 0.9800 |
C3—C4 | 1.390 (9) | C27—H27B | 0.9800 |
C4—C5 | 1.376 (9) | C27—H27C | 0.9800 |
C5—C6 | 1.375 (8) | C28—H28A | 0.9800 |
C7—C12 | 1.404 (8) | C28—H28B | 0.9800 |
C7—C8 | 1.410 (9) | C28—H28C | 0.9800 |
C8—C9 | 1.378 (9) | C29—H29A | 0.9800 |
C9—C10 | 1.382 (9) | C29—H29B | 0.9800 |
C10—C11 | 1.365 (10) | C29—H29C | 0.9800 |
C11—C12 | 1.393 (9) | C30—H30A | 0.9800 |
C13—C14 | 1.396 (8) | C30—H30B | 0.9800 |
C13—C18 | 1.399 (8) | C30—H30C | 0.9800 |
C14—C15 | 1.382 (9) | C31—H31A | 0.9800 |
C15—C16 | 1.391 (10) | C31—H31B | 0.9800 |
C16—C17 | 1.372 (9) | C31—H31C | 0.9800 |
C17—C18 | 1.407 (9) | C32—H32A | 0.9800 |
C19—C24 | 1.389 (9) | C32—H32B | 0.9800 |
C19—C20 | 1.390 (9) | C32—H32C | 0.9800 |
C20—C21 | 1.389 (10) | C33—H33A | 0.9800 |
C21—C22 | 1.387 (10) | C33—H33B | 0.9800 |
C22—C23 | 1.375 (10) | C33—H33C | 0.9800 |
C23—C24 | 1.397 (9) | ||
Se1i—Se1—C25 | 104.37 (16) | C7—C8—H8 | 120.00 |
N1—P1—C1 | 111.4 (2) | C9—C8—H8 | 120.00 |
N1—P1—C7 | 113.9 (3) | C8—C9—H9 | 119.00 |
N1—P1—C25 | 111.2 (3) | C10—C9—H9 | 119.00 |
C1—P1—C7 | 103.4 (3) | C9—C10—H10 | 120.00 |
C1—P1—C25 | 108.6 (3) | C11—C10—H10 | 120.00 |
C7—P1—C25 | 108.1 (3) | C10—C11—H11 | 119.00 |
N2—P2—C13 | 108.3 (3) | C12—C11—H11 | 119.00 |
N2—P2—C19 | 108.3 (3) | C7—C12—H12 | 120.00 |
N2—P2—C25 | 111.6 (3) | C11—C12—H12 | 120.00 |
C13—P2—C19 | 106.6 (3) | C13—C14—H14 | 120.00 |
C13—P2—C25 | 111.1 (3) | C15—C14—H14 | 120.00 |
C19—P2—C25 | 110.7 (3) | C14—C15—H15 | 120.00 |
N1—Si1—C26 | 112.5 (3) | C16—C15—H15 | 120.00 |
N1—Si1—C27 | 113.1 (3) | C15—C16—H16 | 120.00 |
N1—Si1—C28 | 108.7 (3) | C17—C16—H16 | 120.00 |
C26—Si1—C27 | 107.6 (3) | C16—C17—H17 | 120.00 |
C26—Si1—C28 | 107.1 (3) | C18—C17—H17 | 120.00 |
C27—Si1—C28 | 107.6 (3) | C13—C18—H18 | 120.00 |
N2—Si2—C29 | 106.8 (4) | C17—C18—H18 | 120.00 |
N2—Si2—C30 | 105.6 (4) | C19—C20—H20 | 120.00 |
N2—Si2—C31 | 118.1 (4) | C21—C20—H20 | 120.00 |
N2—Si2—C32 | 120.2 (9) | C20—C21—H21 | 120.00 |
N2—Si2—C33 | 94.3 (8) | C22—C21—H21 | 120.00 |
C29—Si2—C30 | 103.6 (5) | C21—C22—H22 | 119.00 |
C29—Si2—C31 | 113.1 (5) | C23—C22—H22 | 119.00 |
C29—Si2—C32 | 130.2 (9) | C22—C23—H23 | 120.00 |
C29—Si2—C33 | 89.7 (9) | C24—C23—H23 | 121.00 |
C30—Si2—C31 | 108.5 (6) | C19—C24—H24 | 120.00 |
C32—Si2—C33 | 101.7 (15) | C23—C24—H24 | 120.00 |
P1—N1—Si1 | 133.9 (3) | Si1—C26—H26A | 109.00 |
P2—N2—Si2 | 134.8 (4) | Si1—C26—H26B | 109.00 |
P2—N2—H2N | 102 (4) | Si1—C26—H26C | 109.00 |
Si2—N2—H2N | 122 (4) | H26A—C26—H26B | 109.00 |
P1—C1—C2 | 118.7 (4) | H26A—C26—H26C | 110.00 |
P1—C1—C6 | 122.9 (4) | H26B—C26—H26C | 109.00 |
C2—C1—C6 | 118.4 (5) | Si1—C27—H27A | 110.00 |
C1—C2—C3 | 120.3 (6) | Si1—C27—H27B | 110.00 |
C2—C3—C4 | 119.9 (6) | Si1—C27—H27C | 109.00 |
C3—C4—C5 | 120.1 (6) | H27A—C27—H27B | 109.00 |
C4—C5—C6 | 120.1 (5) | H27A—C27—H27C | 109.00 |
C1—C6—C5 | 121.1 (5) | H27B—C27—H27C | 109.00 |
P1—C7—C12 | 119.5 (4) | Si1—C28—H28A | 110.00 |
P1—C7—C8 | 121.8 (4) | Si1—C28—H28B | 109.00 |
C8—C7—C12 | 118.5 (5) | Si1—C28—H28C | 109.00 |
C7—C8—C9 | 119.9 (6) | H28A—C28—H28B | 109.00 |
C8—C9—C10 | 121.2 (6) | H28A—C28—H28C | 110.00 |
C9—C10—C11 | 119.5 (6) | H28B—C28—H28C | 109.00 |
C10—C11—C12 | 121.2 (6) | Si2—C29—H29A | 110.00 |
C7—C12—C11 | 119.8 (6) | Si2—C29—H29B | 109.00 |
P2—C13—C14 | 120.8 (4) | Si2—C29—H29C | 109.00 |
P2—C13—C18 | 119.6 (4) | H29A—C29—H29B | 109.00 |
C14—C13—C18 | 119.1 (5) | H29A—C29—H29C | 110.00 |
C13—C14—C15 | 120.8 (6) | H29B—C29—H29C | 109.00 |
C14—C15—C16 | 119.9 (6) | Si2—C30—H30A | 109.00 |
C15—C16—C17 | 120.4 (6) | Si2—C30—H30B | 109.00 |
C16—C17—C18 | 120.2 (6) | Si2—C30—H30C | 109.00 |
C13—C18—C17 | 119.6 (5) | H30A—C30—H30B | 109.00 |
P2—C19—C20 | 122.0 (5) | H30A—C30—H30C | 110.00 |
P2—C19—C24 | 118.1 (4) | H30B—C30—H30C | 109.00 |
C20—C19—C24 | 119.7 (6) | Si2—C31—H31A | 109.00 |
C19—C20—C21 | 120.1 (7) | Si2—C31—H31B | 109.00 |
C20—C21—C22 | 119.4 (7) | Si2—C31—H31C | 109.00 |
C21—C22—C23 | 121.4 (7) | H31A—C31—H31B | 110.00 |
C22—C23—C24 | 119.0 (7) | H31A—C31—H31C | 109.00 |
C19—C24—C23 | 120.5 (6) | H31B—C31—H31C | 109.00 |
P1—C25—P2 | 119.6 (3) | Si2—C32—H32A | 110.00 |
Se1—C25—P1 | 119.7 (3) | Si2—C32—H32B | 109.00 |
Se1—C25—P2 | 116.7 (3) | Si2—C32—H32C | 110.00 |
C1—C2—H2 | 120.00 | H32A—C32—H32B | 109.00 |
C3—C2—H2 | 120.00 | H32A—C32—H32C | 110.00 |
C2—C3—H3 | 120.00 | H32B—C32—H32C | 109.00 |
C4—C3—H3 | 120.00 | Si2—C33—H33A | 109.00 |
C3—C4—H4 | 120.00 | Si2—C33—H33B | 109.00 |
C5—C4—H4 | 120.00 | Si2—C33—H33C | 110.00 |
C4—C5—H5 | 120.00 | H33A—C33—H33B | 109.00 |
C6—C5—H5 | 120.00 | H33A—C33—H33C | 110.00 |
C1—C6—H6 | 119.00 | H33B—C33—H33C | 110.00 |
C5—C6—H6 | 119.00 | ||
Se1i—Se1—C25—P1 | 98.8 (3) | C13—P2—C25—P1 | 84.4 (4) |
Se1i—Se1—C25—P2 | −103.8 (3) | C19—P2—C25—Se1 | 45.3 (4) |
C25—Se1—Se1i—C25i | −180.0 (3) | C19—P2—C25—P1 | −157.3 (3) |
C1—P1—N1—Si1 | 90.8 (4) | C26—Si1—N1—P1 | 65.2 (5) |
C7—P1—N1—Si1 | −25.6 (5) | C27—Si1—N1—P1 | −56.9 (5) |
C25—P1—N1—Si1 | −148.0 (4) | C28—Si1—N1—P1 | −176.3 (4) |
N1—P1—C1—C2 | 8.8 (6) | C29—Si2—N2—P2 | −174.0 (5) |
N1—P1—C1—C6 | −171.4 (5) | C30—Si2—N2—P2 | −64.2 (6) |
C7—P1—C1—C2 | 131.5 (5) | C31—Si2—N2—P2 | 57.2 (7) |
C7—P1—C1—C6 | −48.8 (5) | P1—C1—C2—C3 | 178.2 (5) |
C25—P1—C1—C2 | −114.0 (5) | C6—C1—C2—C3 | −1.6 (10) |
C25—P1—C1—C6 | 65.8 (5) | P1—C1—C6—C5 | −178.5 (5) |
N1—P1—C7—C8 | 90.3 (5) | C2—C1—C6—C5 | 1.2 (9) |
N1—P1—C7—C12 | −84.4 (5) | C1—C2—C3—C4 | 1.4 (11) |
C1—P1—C7—C8 | −30.7 (5) | C2—C3—C4—C5 | −0.8 (11) |
C1—P1—C7—C12 | 154.6 (5) | C3—C4—C5—C6 | 0.4 (10) |
C25—P1—C7—C8 | −145.6 (5) | C4—C5—C6—C1 | −0.6 (10) |
C25—P1—C7—C12 | 39.6 (5) | P1—C7—C8—C9 | −174.4 (5) |
N1—P1—C25—Se1 | 161.3 (3) | C12—C7—C8—C9 | 0.4 (9) |
N1—P1—C25—P2 | 4.6 (4) | P1—C7—C12—C11 | 176.1 (5) |
C1—P1—C25—Se1 | −75.8 (4) | C8—C7—C12—C11 | 1.3 (9) |
C1—P1—C25—P2 | 127.4 (3) | C7—C8—C9—C10 | −1.7 (10) |
C7—P1—C25—Se1 | 35.6 (4) | C8—C9—C10—C11 | 1.4 (10) |
C7—P1—C25—P2 | −121.1 (3) | C9—C10—C11—C12 | 0.3 (10) |
C13—P2—N2—Si2 | 99.9 (5) | C10—C11—C12—C7 | −1.6 (10) |
C19—P2—N2—Si2 | −15.4 (5) | P2—C13—C14—C15 | −171.8 (5) |
C25—P2—N2—Si2 | −137.5 (4) | C18—C13—C14—C15 | −0.3 (10) |
N2—P2—C13—C14 | −173.2 (5) | P2—C13—C18—C17 | 171.2 (5) |
N2—P2—C13—C18 | 15.3 (6) | C14—C13—C18—C17 | −0.4 (10) |
C19—P2—C13—C14 | −56.9 (6) | C13—C14—C15—C16 | 1.2 (10) |
C19—P2—C13—C18 | 131.7 (5) | C14—C15—C16—C17 | −1.3 (11) |
C25—P2—C13—C14 | 63.9 (6) | C15—C16—C17—C18 | 0.6 (11) |
C25—P2—C13—C18 | −107.6 (5) | C16—C17—C18—C13 | 0.3 (10) |
N2—P2—C19—C20 | 97.1 (5) | P2—C19—C20—C21 | −176.3 (5) |
N2—P2—C19—C24 | −77.5 (5) | C24—C19—C20—C21 | −1.8 (9) |
C13—P2—C19—C20 | −19.3 (6) | P2—C19—C24—C23 | 176.8 (4) |
C13—P2—C19—C24 | 166.1 (4) | C20—C19—C24—C23 | 2.1 (8) |
C25—P2—C19—C20 | −140.3 (5) | C19—C20—C21—C22 | 0.7 (10) |
C25—P2—C19—C24 | 45.1 (5) | C20—C21—C22—C23 | 0.2 (10) |
N2—P2—C25—Se1 | 166.0 (3) | C21—C22—C23—C24 | 0.1 (9) |
N2—P2—C25—P1 | −36.6 (4) | C22—C23—C24—C19 | −1.2 (8) |
C13—P2—C25—Se1 | −73.0 (4) |
Symmetry code: (i) −x+1, −y+1, −z. |
D—H···A | D—H | H···A | D···A | D—H···A |
N2—H2N···N1 | 0.99 (8) | 1.86 (8) | 2.795 (8) | 156 (6) |
D—H···A | D—H | H···A | D···A | D—H···A |
N2—H2N···N1 | 0.99 (8) | 1.86 (8) | 2.795 (8) | 156 (6) |
Acknowledgements
The authors thank NSERC (Canada) and the Academy of Finland for financial support.
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This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
Organic diselenides are of interest from the viewpoint of coordination chemistry (Risto et al., 2011) as well as for their structural aspects. The C—Se—Se—C torsion angle typically falls within a wide range of ca. 73–128° (Dickson et al., 1999). The only examples of antiperiplanar diselenides (C—Se—Se—C = 180°) involve very bulky R groups, for example, (Me3Si)3CSeSeC(SiMe3)3 (d(Se—Se) = 2.388 (1) Å) (Wagner et al., 1990), or intramolecular heteroatom coordination to the Se centers as in bis(3,5-dimethyl-2-pyridyl)diselenide (d(Se—Se) = 2.352 (2) Å) (Dhau et al., 2011). In this work we unexpectedly isolated a small amount of the title diselenide as red crystals from the reaction of {Li2[C(PPh2NSiMe3)2]} with SeCl4 (1:1 molar ratio) in pentane.
The crystal structure analysis of the title compound revealed a centrosymmetric dimer in which a diselenido (–Se—Se-) unit bridges two monoprotonated units (Fig. 1). The torsion angle C25—Se—Sei—C25i is 180 °, as a result of the inversion centre, and the two anionic ligands are in a trans orientation with respect to –Se—Se- bridge. The Se—Se bond length of 2.4717 (8) Å is substantially longer than those in typical diaryl diselenides (range 2.29–2.35 Å) [Dickson et al., 1999]. At the same time the Se—C bond of 1.876 (5) Å is short in comparison with the range of values found for other diselenides (1.91–1.97 Å) (Back & Codding, 1983) and the calculated value of 1.91 Å (Pyykkö & Atsumi, 2009). This bonding arrangement is reminiscent of the alternation of the S—S bond lengths in cycloheptasulfur, which has been rationalized in terms of p lone pair repulsions of the neighbouring sulfur atoms due to the torsion angle of 0° and hyperconjugation (Steudel et al., 1980). We also note that the Se—Se bond lengths of 2.492 (2) Å found for the dication [(Ph3P)2CSe-SeC(PPh3)2]2+ (Schmidbaur et al., 1983) and 2.508 (1) Å exhibited by the dilithium complex {[Li(TMEDA)]2[(SPh2P)2CSe-SeC(PPh2S)2]} (Konu et al., 2010) are comparable to that of the title compound. In the latter case, the Se—Se bonding interaction is due solely to the poor overlap of the SOMOs of the anion radicals. Consequently the calculated binding energy is small (90 kJ mol-1) compared to typical values for organic diselenides, e.g. 172 kJ mol-1 for PhSe-SePh (McDonough et al., 2005). The Se—C distance of 1.885 (3) Å in [{Li(TMEDA)}2{(SPh2P)2CSe-SeC(PPh2S)2}] (Konu et al., 2010) is also comparable with that in the title compound.
The protonation of one of the nitrogen atoms, N1, is evident from the disparity of ca 0.07 Å in the P—N bond lengths, and smaller differences in the Si—N and P—C(Se) distances of 0.038 Å and 0.036 Å, respectively. Intramolecular hydrogen bonding between the N—H functionality and two-coordinate nitrogen atom (1.981 (15) Å) is observed (Table 1). The geometry at the three-coordinate carbon atom is almost planar (Σ<C(25) = 356.1°).
In the crystal, there are no significant intermolecular interactions present.