Dicyclohexylamine hydrogen peroxide hemisolvate

The mol­ecules of the title complex, C12H23N·0.5H2O2, are linked together by O—H⋯N and N—H⋯O hydrogen bonds to give ten-membered rings, which form flat ribbons parallel to the a axis. Centrosymmetric H2O2 mol­ecules, as well as amino groups, act as both donors and acceptors of hydrogen bonds.

The molecules of the title complex, C 12 H 23 NÁ0.5H 2 O 2 , are linked together by O-HÁ Á ÁN and N-HÁ Á ÁO hydrogen bonds to give ten-membered rings, which form flat ribbons parallel to the a axis. Centrosymmetric H 2 O 2 molecules, as well as amino groups, act as both donors and acceptors of hydrogen bonds.

Comment
Hydrogen peroxide solvates are widely used as environmentally friendly bleaching compounds (Pritchard & Islam, 2003;Cosgrove & Jones, 1998) and oxidation agents in organic synthesis (McKillop & Sanderson, 2000). Hydrogen bonding plays the main role in forming crystals of peroxosolvates. It was supposed that it might be possible to design stable hydrogen peroxide carriers by maximizing the number of hydrogen bonds in the structure (Adams & Ramdas, 1978). However, due to their low stability, very few organic peroxosolvates have been structurally characterized to datethere are 19 entries in Cambridge Structural Database (CSD, Version 5.27, January 2006;Allen, 2002). Here, we report the structure of the title new peroxosolvate molecular complex of dicyclohexylamine with hydrogen peroxide, (I).
In the structure of (I), the dicyclohexylamine molecule exhibits the expected molecular geometry and both cyclohexyl rings adopt a chair conformation, with the amine group occupying equatorial positions (Fig. 1).
Both components of complex (I) are linked together by a system of hydrogen bonds (Fig. 2). Atom N1 acts as both a donor and an acceptor of hydrogen bonds for adjacent H 2 O 2 molecules. The amine group of dicyclohexylamine also forms two hydrogen bonds with cocrystallized molecules in the structures of crystalline complexes with 2,4-di-tert-butylphenol (Komissarova et al., 2003) and cyclohexanone oxime (Chetina et al., 2006). The H 2 O 2 molecule of (I) is involved in four hydrogen bonds with adjacent dicyclohexylamine molecules, forming two donor and two acceptor interactions. Thus, all 'active' H atoms (both amino and peroxo) are engaged in hydrogen bonding in (I).
Two dicyclohexylamine molecules and two H 2 O 2 molecules are linked by hydrogen bonds into a ten-membered ring. Peroxide molecules fuse these rings together, forming flat ribbons or tapes parallel to the a axis.
During the preparation of this manuscript, the latest update of the CSD has been released (May 2006), which contains the structure of compound (I) as a private communication (refcode VAYGUY; Hursthouse et al., 2006). The reported structure was determined at a different temperature to the present work, but the main structural features are similar to those we have found in (I).

Experimental
Dicyclohexylamine (99%) and 50% hydrogen peroxide were purchased from Aldrich. Hydrogen peroxide (50%, 0.2 ml; = 1.18 Mg m À3 ) was placed in a sample bottle (9 mm diameter) and covered with a 1:2 mixture of dichloromethane and benzene (approximately 1 ml; ' 1.0 Mg m À3 ). Finally, the organic layer was carefully covered with dicyclohexylamine (0.1 ml; = 0.91 Mg m À3 ). After a few hours, several crystals (up to 5 mm in length) were observed on the wall of the sample bottle. Crystals of (I) decompose slowly in air.  Table 1 Selected geometric parameters (Å , ).

Table 2
Hydrogen-bond geometry (Å , ). All H atoms were located in a difference Fourier map and refined isotropically. In the final stages of the refinement, no residual peaks with intensity greater than 0.13 e A À3 were found in the hydrogen peroxide region, indicating the complete occupancy of this site by organic papers The structure of (I), showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. The dashed line indicates a hydrogen bond. [Symmetry code: (i) Àx, 1 À y, 1 À z.]

Figure 2
The hydrogen-bonded (dashed lines) chains in (I), parallel to the a axis. H atoms not involved in hydrogen bonds have been omitted.
H 2 O 2 molecules and the absence of partial peroxide/water substitution (Churakov et al., 2005).
AVC is grateful to the Russian Science Support Foundation.  Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.