Crystal structure of O-isopropyl [bis­(tri­methyl­sil­yl)amino](tert-butyl­amino)­phosphino­thio­ate

Oleksandr O Kovalenko; Vasyl Kinzhybalo; Oleksii A Brusylovets; Tadeusz Lis

doi:10.1107/S205698901402622X

. 2015 Jan 1;71(Pt 1):o37–o38. doi: 10.1107/S205698901402622X

Crystal structure of O-isopropyl [bis(trimethylsilyl)amino](tert-butylamino)phosphinothioate

Oleksandr O Kovalenko ^a,^*, Vasyl Kinzhybalo ^b, Oleksii A Brusylovets ^a, Tadeusz Lis ^c

PMCID: PMC4331855 PMID: 25705495

Abstract

[Bis(trimethylsilyl)amino](tert-butylimino)thiophosphorane reacts in benzene with isopropyl alcohol via 1,2-addition of an ⁱPrO–H bond across the P=N bond, resulting in the title compound, C₁₃H₃₅N₂OPSSi₂. In the molecule, the P atom possesses a distorted tetrahedral environment involving two N atoms from (Me₃Si)₂N– and ^tBuNH– groups, one O atom from an ⁱPrO group and one S atom, therefore the molecule has a stereocenter on the P atom but crystal symmetry leads to a racemate. In the crystal, a pair of enantiomers form a centrosymmetric dimer via a pair of N—H⋯S hydrogen bonds.

Keywords: crystal structure, (trimethylsilyl)amino, phosphinothioate, N—H⋯S hydrogen bonding

Related literature

For details of the synthesis of [bis(trimethylsilyl)amino](tert-butylimino)thiophosphorane, see: Scherer & Kuhn (1974 ▸). For its chemical reactivity, see: Kovalenko et al. (2011a ▸,b ▸,c ▸, 2012 ▸); Rusanov et al. (1992 ▸); Scherer et al. (1978 ▸). For its applications in catalysis, see: Zhao et al. (2014a ▸,b ▸); Goldys & Dixon (2014 ▸); Samuel et al. (2014 ▸); Kawalec et al. (2012 ▸); Zhang et al. (2007 ▸). graphic file with name e-71-00o37-scheme1.jpg

Experimental

Crystal data

C₁₃H₃₅N₂OPSSi₂
M _r = 354.64
Monoclinic,
a = 9.942 (3) Å
b = 11.907 (3) Å
c = 17.726 (5) Å
β = 100.52 (3)°
V = 2063.1 (10) Å³
Z = 4
Mo Kα radiation
μ = 0.35 mm⁻¹
T = 100 K
0.30 × 0.20 × 0.20 mm

Data collection

Oxford Xcalibur PX κ-geometry diffractometer with a CCD area detector
36939 measured reflections
7436 independent reflections
5938 reflections with I > 2σ(I)
R _int = 0.033

Refinement

R[F ² > 2σ(F ²)] = 0.041
wR(F ²) = 0.115
S = 1.08
7436 reflections
184 parameters
H atoms treated by a mixture of independent and constrained refinement
Δρ_max = 0.84 e Å⁻³
Δρ_min = −0.34 e Å⁻³

Data collection: CrysAlis CCD (Oxford Diffraction, 2003 ▸); cell refinement: CrysAlis RED (Oxford Diffraction, 2003 ▸); data reduction: CrysAlis RED; program(s) used to solve structure: SHELXS2014 (Sheldrick, 2008 ▸); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2008 ▸); molecular graphics: ORTEP-3 for Windows (Farrugia, 2012 ▸); software used to prepare material for publication: publCIF (Westrip, 2010 ▸).

Supplementary Material

Crystal structure: contains datablock(s) I, New_Global_Publ_Block. DOI: 10.1107/S205698901402622X/xu5831sup1.cif

e-71-00o37-sup1.cif^{(1.2MB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S205698901402622X/xu5831Isup2.hkl

e-71-00o37-Isup2.hkl^{(407.4KB, hkl)}

Click here for additional data file.^{(6.8KB, cml)}

Supporting information file. DOI: 10.1107/S205698901402622X/xu5831Isup3.cml

Click here for additional data file.^{(1.8MB, tif)}

ORTEP . DOI: 10.1107/S205698901402622X/xu5831fig1.tif

An ORTEP view of the molecular structure of the title compound, with atom labels and 50% probability displacement ellipsoids for non-H atoms.

CCDC reference: 1036750

Additional supporting information: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (, ).

DHA	DH	HA	D A	DHA
N2H2Sⁱ	0.848(16)	2.631(16)	3.4326(13)	158.2(14)

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Symmetry code: (i) Inline graphic .

supplementary crystallographic information

S1. Comments

[Bis(trimethylsilyl)amino](tert-butylimino)thiophosphorane was first synthesized by Scherer and Kuhn in 1974, see: Scherer & Kuhn (1974), and later some general chemical reactivity of this compound was studied, see: Scherer et al. (1978). Based on these early results, pentavalent tricoordinated σ³λ⁵-phosphoranes recommended themselves as promising ligands for the obtaining of new organometallic metallacycles with specific features. Recently we have reported and characterized series of transition metal metallacycles, containing phosphorus atom in cyclic moiety, see: Kovalenko et al. (2011a, 2011b, 2011c, 2012); Rusanov et al. (1992). In current communication we reported the reactivity of [bis(trimethylsilyl)amino](tert-butylimino)-thiophosphorane with isopropyl alcohol. The reaction proceeds through a 1,2-addition of ⁱPrO–H bond across the P=N bond, resulting in the title compound. Resulted product was characterized by single X-ray analysis and ¹H, ¹³C and ³¹P NMR spectroscopy. In these latter days it was discovered that low-coordinate phosphorus compounds are catalytically active and might be efficiently applied in catalysis, see: Zhao et al. (2014a, 2014b); Goldys & Dixon (2014); Samuel et al. (2014); Kawalec et al. (2012); Zhang et al. (2007).

Central P atom posesses distorted tetrahedral environment of four different substituents: (Me₃Si)₂N-, ^tBuNH- and ⁱPrO- groups and S atom, resulting in stereocenter on phosphorus. R and S isomers form centrosymmetric dimers due to the formation of a pair of N—H···S type hydrogen bonds. Geometrical parameters of O-isopropyl [bis(trimethylsilyl)amino](tert-butylamino)phosphinothioate are consistent with the values reported earlier (Rusanov et al., 1992; Kovalenko et al., 2011a, 2011b) for the compounds containing analogous phosphinothioates, but deprotonated and coordinated to metal centers.

S2. Experimental

All procedures were carried out under a dry argon atmosphere using standard Schlenk and glovebox techniques. Benzene and hexane were distilled from sodium-potassium alloy directly before use. Isopropyl alcohol was dried and distilled from magnesium and stored over 4 Å molecular sieves prior to use.

In a Schlenk flask, (0.884 g, 3.0 mmol) of [bis(trimethylsilyl)amino](tert-butylimino)thiophosphorane was dissolved in 3 ml of benzene and the solution of isopropyl alcohol (0.23 ml, 3.0 mmol) in 1 ml of benzene was added dropwise. The mixture was stirred for 1.5 h at room temperature, thereafter solvent was removed in vacuo producing an almost colorless tar. The residue was dissolved in 1 ml of hexane and kept at 252 K in order to induce further crystallization. Yield: 0.76 g, 71% of colorless crystals. ¹H NMR (400 MHz, C₆D_6, 298K): δ 5.00 (m, 1H), 2.45 (d, ²J_P—H=10.3 Hz, 1H), 1.27 (d, ³J_H—H=6.0 Hz, 3H), 1.19 (d, ³J_H—H=6.0 Hz, 3H), 1.15 (s, 9H), 0.47 (18H); ¹³C{¹H} NMR (100 MHz, C₆D_6, 298K): δ 71.52 (d, ²J_P—C=4.6 Hz), 52.72 (d, ²J_P—C=4.6 Hz), 31.58, 31.53, 23.98, 23.92, 5.26 (d, ³J_P—C=2.3 Hz); ³¹P{¹H} NMR (162 MHz, C₆D_6, 298K): δ 63.24 (dd, ²J_P—H=10.3 Hz, ³J_P—H=10.3 Hz).

S3. Refinement

Positions of hydrogen atoms bonded to carbon were generated in idealized geometries using a riding model with U_iso(H) = 1.5U_eq(C) or 1.2U_eq(C). The fractional coordinates of the H atom attached to N2 were identified from a difference Fourier map and refined freely with isotropic thermal displacement parameter.