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BY-NC-ND 4.0 license Open Access Published by De Gruyter (O) September 27, 2018

Crystal structure of [(1,2-η)-1,2,3,4,5-pentamethyl-cyclopenta-2,4-dien-1-yl] (1,4,10,13-tetraoxa-7,16-diazacyclooctadecane-κ6N2,O4) rubidium (I), [Rb(diaza-18-crown-6)]Cp*, C22H41N2O4Rb

Thomas Henneberger, Wilhelm Klein and Thomas F. Fässler

Abstract

C22H41N2O4Rb, monoclinic, P21/n (no. 14), a = 10.8160(9) Å, b = 17.7253(16) Å, c = 13.2179(12) Å, β = 93.961(8)°, V = 2528.0(4) Å3, Z = 4, Rgt(F) = 0.0376, wRref(F2) = 0.0694, T = 120(2) K.

CCDC no.: 1866601

The crystal structure is shown in the figure. Tables 1 and 2 contain details on crystal structure and measurement conditions and a list of the atoms including atomic coordinates and displacement parameters.

Table 1:

Data collection and handling.

Crystal:Yellow block
Size:0.20 × 0.15 × 0.15 mm
Wavelength:Mo Kα radiation (0.71073 Å)
μ:1.99 mm−1
Diffractometer, scan mode:Oxford Xcalibur 3, ω and π
θmax, completeness:26.0°, >99%
N(hkl)measured, N(hkl)unique, Rint:26792, 4963, 0.100
Criterion for Iobs, N(hkl)gt:Iobs > 2 σ(Iobs), 2435
N(param)refined:272
Programs:CrysAlis [1], SHELX [2, 3] , Diamond [4]

Table 2:

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2).

AtomxyzUiso*/Ueq
Rb0.44660(3)0.33795(2)0.34703(3)0.03586(11)
O10.7034(2)0.30542(13)0.30666(16)0.0386(6)
C10.7869(3)0.3673(2)0.3013(3)0.0477(11)
H1A0.86070.35150.26640.057*
H1B0.81470.38410.37060.057*
C20.7224(3)0.4307(2)0.2443(3)0.0465(11)
H2A0.78280.47070.23040.056*
H2B0.68470.41210.17860.056*
O20.6287(2)0.46052(12)0.30345(16)0.0404(6)
C30.5591(4)0.5184(2)0.2503(3)0.0531(12)
H3A0.51140.49680.19060.064*
H3B0.61590.55730.22620.064*
C40.4717(4)0.5537(2)0.3211(3)0.0531(11)
H4A0.51960.57270.38230.064*
H4B0.42880.59710.28700.064*
N10.3790(3)0.49846(17)0.3511(2)0.0430(9)
H10.329(3)0.4852(19)0.295(2)0.052*
C50.3108(4)0.5236(2)0.4372(3)0.0581(12)
H5A0.26610.57090.41850.070*
H5B0.37060.53470.49540.070*
C60.2197(4)0.4658(2)0.4685(3)0.0576(12)
H6A0.17240.48630.52390.069*
H6B0.16030.45380.41050.069*
O30.2834(2)0.39923(13)0.50214(17)0.0406(6)
C70.2026(3)0.3442(2)0.5399(2)0.0475(10)
H7A0.14130.32800.48520.057*
H7B0.15720.36610.59540.057*
C80.2770(3)0.2783(2)0.5783(3)0.0445(10)
H8A0.34140.29530.63020.053*
H8B0.22250.24190.61060.053*
O40.3341(2)0.24242(13)0.49762(16)0.0392(6)
C90.3971(3)0.1748(2)0.5307(3)0.0437(10)
H9A0.33590.13470.54230.052*
H9B0.44630.18430.59540.052*
C100.4814(3)0.14978(19)0.4509(2)0.0411(9)
H10A0.51490.09910.46810.049*
H10B0.43360.14650.38430.049*
N20.5828(3)0.20283(17)0.4444(2)0.0366(8)
H20.625(3)0.2010(18)0.500(2)0.044*
C110.6684(3)0.18081(19)0.3684(2)0.0402(10)
H11A0.62150.17180.30260.048*
H11B0.71090.13330.38960.048*
C120.7631(3)0.2419(2)0.3565(3)0.0412(10)
H12A0.80040.25720.42390.049*
H12B0.83010.22290.31590.049*
C130.3113(3)0.29258(19)0.1439(3)0.0360(9)
C140.3567(3)0.3535(2)0.0906(2)0.0366(9)
C150.2813(3)0.4169(2)0.1046(3)0.0364(9)
C160.1884(3)0.39450(19)0.1681(3)0.0353(9)
C170.2064(3)0.31836(19)0.1926(2)0.0350(9)
C180.3655(3)0.21497(19)0.1515(3)0.0477(10)
H18A0.31950.18500.19630.072*
H18B0.36120.19210.08550.072*
H18C0.45040.21800.17750.072*
C190.4695(3)0.3515(2)0.0262(3)0.0499(10)
H19A0.50000.29960.02240.075*
H19B0.53510.38380.05740.075*
H19C0.44540.3699−0.04230.075*
C200.2902(3)0.4927(2)0.0539(3)0.0535(11)
H20A0.29110.53260.10530.080*
H20B0.21860.49970.00530.080*
H20C0.36660.49500.01830.080*
C210.0851(3)0.44569(19)0.1991(3)0.0496(11)
H21A0.11980.49470.22060.074*
H21B0.04440.42260.25550.074*
H21C0.02440.45290.14140.074*
C220.1287(3)0.27075(19)0.2596(3)0.0434(10)
H22A0.07920.30380.30040.065*
H22B0.18330.23950.30460.065*
H22C0.07340.23820.21710.065*

Source of material

The Zintl phase Rb12Si17 [5] was prepared from stoichiometric mixtures of the elements in sealed tantalum containers, which were encapsulated in an evacuated fused silica tube. The mixture was heated to 800 °C for 15 h and slowly cooled to room temperature with a rate of 0.5 °C/min. Bis(pentamethylcyclopentadienyl)zinc (ZnCp*2) was prepared as described in literature [6]. 113 mg Rb12Si17, 35 mg 1,4,10,13-tetraoxa-7,16-diazacyclooctadecane (diaza-18-crown-6; Merck, p. a.), and 25 mg Zn2Cp*2 were placed in into a dry Schlenk vessel and ca 2 mL NH3 (Westfalen, 99.999%, stored over elemental Na) were condensed on this. The obtained light yellow solution was stored at −70 °C for 11 months, after this time yellow crystals of the title compound were found. An appropriate crystal was selected under perfluoroalkylether in a stream of cold nitrogen gas.

Experimental details

The methylene and methyl H atoms have been refined using a riding model with Uiso set to 1.2 and 1.5 Ueq(C), respectively. The H atoms bound to N Atoms have been located from the difference Fourier map and refined with free atomic coordinates and an Uiso of 1.2 Ueq(N) [3].

Comment

During our investigations of the behaviour and reactivity of Si containing Zintl compounds in solution with the goal to synthesize transition metal complexes with Si clusters as ligands analogously to the known Ge compounds [7], liquid ammonia has been found to be a highly suitable solvent [8, 9] . For supporting the dissolution of the solid Zintl compounds often sequestering agents like crown ethers or cryptands are necessary. In the present experiment, diaza-18-crown-6 has been used to dissolve Rb12Si17 in liquid ammonia in presence of ZnCp*2. The title compound has been obtained as a crystallized product of a partial metathesis reaction, while the remaining ingredients, Zn2+ cations as well as [Si4]4− and [Si9]4− cluster anions, were not found as parts of crystalline phases after this experiment.

[Rb(diaza-18-crown-6)]Cp* crystallizes in space group P21/c with all atoms at general positions. The Rb+ cation is coordinated by one diaza-18-crown-6 molecule and one Cp* anion. While pure RbCp* is found to crystallize in polymeric “multidecker” strands [10], here the presence of the crown ether causes the formation of molecular units, similar to the effect of 18-crown-6 on RbCp* in THF [11]. The Rb+ cation is situated near the centre of the diaza-18-crown-6 molecule but apart from the ring plane shifted in direction of the Cp* anion as previously found for [Rb(diaza-18-crown-6)] complexes in Fulleride salts [12]. Rb is bound to the Cp* ligand via two short Rb—C bonds of 3.075(3) Å and 3.210(3) Å which are in the same range as those observed for the η5 coordination in [Rb(18-crown-6)]Cp* [11]. All atoms of the Cp* ligand are in plane and the cyclopentadienyl ring is a nearly perfect pentagon (C—C bond lengths between 1.398(4) Å and 1.418(4) Å, C—C—C angles between 107.3(3)° and 108.8(3)°) which differs clearly from the shape of the neutral Cp*–H molecule [13], suggesting that the negative charge is located at Cp*. Confirming the neutral nature of the diaza-18-crown-6 molecule, one H atom close to each N atom could have been located from the Fourier map. In contrast to the structure of the free diaza-18-crown-6 molecule [14], where the N—H bonds are parallel, both the N—H bonds of the [Rb(diaza-18-crown-6)] complex are directed almost perpendicular to the ring plane. Probably the orthogonal N—H bond hampers the formation of the symmetric η5 coordination, possibly by forming N—H⋯C hydrogen bonds instead.

Acknowledgements

This work was supported by the Deutsche Forschungsgesellschaft (DFG) and the Technische Universität München within the funding programme Open Access Publishing. We thank Kerstin Mayer for the preparation of ZnCp*2.

References

Rigaku Oxford Diffraction: CrysAlis CCD, CrysAlis RED Version 1.171.33.34d. Oxford Diffraction Ltd., Yarnton, Oxfordshire, UK (2009).Search in Google Scholar

Sheldrick, G. M.: A short history of SHELX. Acta Crystallogr. A64 (2008) 112–122.10.1107/S0108767307043930Search in Google Scholar

Sheldrick, G. M.: Crystal structure refinement with SHELXL. Acta Crystallogr. C71 (2015) 3–8.10.1107/S2053229614024218Search in Google Scholar

Brandenburg, K.: DIAMOND. Visual Crystal Structure Information System. Version 3.2i. Crystal Impact, Bonn, Germany (2012).Search in Google Scholar

Quéneau, V.; Todorov, E.; Sevov, S. C.: Synthesis and structure of isolated silicon clusters of nine atoms. J. Am. Chem. Soc. 120 (1998) 3263–3264.10.1021/ja980044wSearch in Google Scholar

Blom, R.; Boersma, J.; Budzelaar, P. H. M.; Fischer, B.; Haaland, A.; Volden, H. V.; Weidlein, J.: The preparation of bis(pentamethylcyclopentadienyl)zinc and bis(trimethylsilylcyclopentadienyl)zinc, and their molecular structures determined by gas electron diffraction. Acta Chem. Scand. A 40 (1986) 113–120.10.3891/acta.chem.scand.40a-0113Search in Google Scholar

Bentlohner, M. M.; Jantke, L.-A.; Henneberger, T.; Fischer, C.; Mayer, K.; Klein, W.; Fässler, T. F.: On the nature of cridging metal atoms in intermetalloid clusters: synthesis and structure of the metal-atom-bridged zintl clusters [Sn(Ge9)2]4− and [Zn(Ge9)2]6−. Chem. Eur. J. 22 (2016) 13946–13952.10.1002/chem.201601706Search in Google Scholar

Benda, C. B.; Henneberger, T.; Klein, W.; Fässler, T. F.: [Si4]4− and [Si9]4− clusters crystallized from liquid ammonia solution – synthesis and characterization of K8[Si4][Si9](NH3)14.6. Z. Anorg. Allg. Chem. 643 (2017) 146–148.10.1002/zaac.201600369Search in Google Scholar

Henneberger, T.; Klein, W.; Fässler, T. F.: Silicon containing nine atom clusters from liquid ammonia solution: crystal structures of the first protonated clusters [HSi9]3− and [H2{Si/Ge}9]2. Z. Anorg. Allg. Chem. 644 (2018) 1018–1027.10.1002/zaac.201800227Search in Google Scholar

Behrens, U.; Dinnebier, R. E.; Neander, S.; Olbrich, F.: Solid-state structures of base-free rubidium and cesium pentamethylcyclopentadienides. Determination by high-resolution powder diffraction. Organometallics 27 (2008) 5398–5400.10.1021/om800617gSearch in Google Scholar

Neander, S.; Behrens, U.; Olbrich, F.: Novel 18-crown-6 organometallic rubidium and cesium complexes containing cyclopentadienyl, indenyl, pentamethylcyclopentadienyl, and fluorenyl as carbanions. J. Organomet. Chem. 604 (2000) 59–67.10.1016/S0022-328X(00)00202-3Search in Google Scholar

Boeddinghaus, M. B.; Wahl, B.; Fässler, T. F.; Jakes, P.; Eichel, R.-A.: Three salts containing the fullerene tetra-anion C604− – synthesis, X-ray single-crystal structure determination and EPR investigation. Z. Anorg. Allg. Chem. 638 (2012) 2205–2212.10.1002/zaac.201200272Search in Google Scholar

Benda, C. B.; Klein, W.; Fässler, T. F.: Crystal structure of 1,2,3,4,5-pentamethyl-1,3-cyclopentadiene, C10H16. Z. Kristallogr. NCS 232 (2017) 511–512.10.1515/ncrs-2016-0402Search in Google Scholar

Dokurno, P.; Trokowski, R.; Kościuszko-Panek, B.; Ossowski, T.; Konitz, A.; Blażejowski, J.: Crystal structure of three diaza-crowns-18. Z. Kristallogr. 212 (1997) 362–366.10.1524/zkri.1997.212.5.362Search in Google Scholar

Received: 2018-07-19
Accepted: 2018-09-09
Published Online: 2018-09-27
Published in Print: 2018-12-19

©2018 Thomas Henneberger et al., published by De Gruyter, Berlin/Boston

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