Dicyclo­hex­yl(4-isopropyl­phen­yl)phosphane selenide

Sizwe Makhoba; Alfred Muller; Zanele Phasha

doi:10.1107/S1600536812004643

. 2012 Feb 10;68(Pt 3):o648. doi: 10.1107/S1600536812004643

Dicyclohexyl(4-isopropylphenyl)phosphane selenide

Sizwe Makhoba ^a, Alfred Muller ^a,^*, Zanele Phasha ^a

PMCID: PMC3295440 PMID: 22412551

Abstract

In the title compund, C₂₁H₃₃PSe, the Se=P bond is part of a distorted tetrahedral environment on the P atom. Both cyclohexyl groups adopt chair conformations. A cone angle of 170° was calculated using an adaptation of the Tolman model. Intermolecular C—H⋯Se and C—H⋯Cg contacts are observed (Cg is the centroid of the benzene ring).

Related literature

For background studies aimed at understanding the transition metal–phosphorus bond, see: Muller et al. (2008 ▶); Roodt et al. (2003 ▶). For transition metal complexes with PCy₂(4-ⁱPr—C₆H₄), see: Makhoba et al. (2011 ▶); Vuba & Muller (2012 ▶). For background to cone angles, see: Tolman (1977 ▶).

Experimental

Crystal data

C₂₁H₃₃PSe
M _r = 395.4
Monoclinic,
a = 13.1311 (10) Å
b = 13.6991 (10) Å
c = 11.7821 (8) Å
β = 103.106 (2)°
V = 2064.2 (3) Å³
Z = 4
Mo Kα radiation
μ = 1.90 mm⁻¹
T = 100 K
0.22 × 0.14 × 0.1 mm

Data collection

Bruker APEX DUO 4K CCD diffractometer
Absorption correction: multi-scan (SADABS; Bruker, 2008 ▶) T _min = 0.681, T _max = 0.833
28000 measured reflections
5140 independent reflections
4397 reflections with I > 2σ(I)
R _int = 0.040

Refinement

R[F ² > 2σ(F ²)] = 0.023
wR(F ²) = 0.057
S = 1.02
5140 reflections
210 parameters
H-atom parameters constrained
Δρ_max = 0.41 e Å⁻³
Δρ_min = −0.24 e Å⁻³

Data collection: APEX2 (Bruker, 2011 ▶); cell refinement: SAINT (Bruker, 2008 ▶); data reduction: SAINT and XPREP (Bruker, 2008 ▶); program(s) used to solve structure: SIR97 (Altomare et al., 1999 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: DIAMOND (Brandenburg & Putz, 2005 ▶); software used to prepare material for publication: WinGX (Farrugia, 1999 ▶).

Supplementary Material

Crystal structure: contains datablock(s) global, I. DOI: 10.1107/S1600536812004643/kp2386sup1.cif

e-68-0o648-sup1.cif^{(21.7KB, cif)}

Structure factors: contains datablock(s) I. DOI: 10.1107/S1600536812004643/kp2386Isup2.hkl

e-68-0o648-Isup2.hkl^{(246.7KB, hkl)}

Supplementary material file. DOI: 10.1107/S1600536812004643/kp2386Isup3.cml

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Table 1. Hydrogen-bond geometry (Å, °).

Cg1 is the centroid of the C13–C18 benzene ring.

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
C1—H1⋯Se1ⁱ	1.00	3.09	4.0500 (14)	162
C9—H9B⋯Cg1ⁱⁱ	0.99	2.81	3.6471	143

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Symmetry codes: (i) Inline graphic ; (ii) .

Acknowledgments

Research funding from the University of Johannesburg is gratefully acknowledged.

supplementary crystallographic information

Comment

The bonding of phosphorus to transitional metals have being investigated extensively, with several attempts to divide the properties of the phosphorus ligand into steric and electronic effects. Various techniques such as single-crystal X-ray crystallography, multi nuclear NMR and IR (Roodt et al., 2003) have been used to this extent. Recently we have also included selenium derivatives of the phosphorus compounds into this study (Muller et al., 2008). This route seems viable as the use of expensive transition metals and steric influence from other ligands in the coordination sphere are eliminated, leaving only crystal packing effects as an additional influence on the steric property of the phosphorus ligand. As part of this investigation we report here the selenium derivative of PCy₂(4-ⁱPr—C₆H₄) where Cy = cyclohexyl and ⁱPr = isopropyl.

Molecules of the title compound (Fig. 1) adopts a distorted tetrahedral arrangement about the P atom with average C—P—C and Se—P—C angles of 106.0° and 112.7° respectively. The cone angle was found to be 170° when the Se—P distance was adjusted to 2.28 Å (the default value from Tolman, 1977). This value is ca 5° larger than previous reported values where the present phosphine was bonded to a transition metal centre (Makhoba et al., 2011; Vuba & Muller, 2012). This indicates to some extend the flexibility of this phosphine ligand and its ability to use space to enable less crowding of its substituents. Weak intermolecular C—H···Se and C—H···Cg contacts are observed (Table 1, Fig. 2) and link the molecules as infinite chains in the [001] direction.

Experimental

KSeCN (10 mg, 0.0694 mmol) and PCy₂(4-ⁱPr—C₆H₄) (21.96 mg, 0.0694 mmol) were both dissolved in a minimum amount of methanol (10–20 ml). The KSeCN solution was added drop wise (5 min) to the phosphine solution while stirring at room temperature. The final solution was left to evaporate slowly in order to give crystals that are suitable for single-crystal X-ray study.