Chlorido(2-{(2-hydroxyethyl)[tris(hydroxymethyl)methyl]amino}ethanolato-κ5 N,O,O′,O′′,O′′′)copper(II)

The crystal structure of the title complex features O—H⋯O hydrogen bonds, which form (8), (16), (20) and (22) ring motifs.


Aminopolyol
[bis(2-hydroxyethyl)amino]tris(hydroxymethyl)methane, generally abbreviated H 5 bis-tris, is able to coordinate first-row late transition metals and lanthanides (Nicholson et al., 2001).This molecule behaves systematically as a chelating pentadentate ligand, through the tertiary N atom and four of the five alcohol arms.The metal coordination sphere is then completed with an ancillary ligand, frequently an aqua or a chlorido ligand.Furthermore, depending on the reaction conditions, H 5 bis-tris can be deprotonated, affording chelating anions.While anions (H 5-n bis-tris) nÀ with n = 2 to 4 have been determined by X-ray structure analysis in several compounds (e.g.Stamatatos et al., 2009), it seems that to date the anionic ligand with n = 1, (H 4 bis-tris) À , has been observed only once: Kirillova et al. (2017) reported a crystal structure comprising [Cu(H 5 bis-tris)(inic)] + and [Cu(H 4 bis-tris)(inic)] entities, where inic stands for the isonicotinate anion.We now report the structure of the second complex where (H 4 bis-tris) À acts as a ligand, namely [Cu(H 4 bis-tris)Cl], which was obtained serendipitously from [Cu(H 5 bis-tris)Cl] + Cl (Inomata et al., 2004).
The new Cu II molecular complex displays the expected distorted octahedral shape (Fig. 1).Since all H atoms could be located from electron-difference maps, the deprotonated alcohol group was clearly identified as being O5.Moreover, the anion formula for (H 4 bis-tris) À is consistent with the charge balance in the complex.The tetragonal distortion resulting from the Jahn-Teller effect for Cu II  The space group and the network of hydrogen bonds are however modified upon deprotonation of H 5 bis-tris.In the new complex, all hydroxy groups are donors for hydrogen bonding, and the deprotonated hydroxy group, O5, is an acceptor (Table 1).The latter is engaged in the strongest interaction, O2-H2� � �O5, with a very short H2� � �O5 distance of 1.553 (19) A ˚and with an angle O2-H2� � �O5 = 178 (4) � .Indeed, only few shorter intermolecular H� � �O separations  Molecular structure of the title compound, with displacement ellipsoids for non-H atoms at the 60% probability level.The inset is an overlay calculated with Mercury (Macrae et al., 2020), comparing the shape of [Cu(H 5 bis-tris)Cl] + (blue) and the title complex [Cu(H 4 bis-tris)Cl] (red).The crystal structure of [Cu(H 5 bis-tris)Cl]Cl has been published (Inomata et al., 2004; CCDC refcode FIPRAY); however, the authors did not deposit a CIF file at that time.A CSD communication for this compound was thus used for the fit (FIPRAY01; Fortis-Valera et al., 2018).

Figure 2
The supramolecular framework based on intermolecular O-H� � �(O, Cl) hydrogen bonds (dashed blue lines) corresponding to entries 1-3 in Table 1.The inset shows single crystals suitable for X-ray diffraction.

Figure 3
The supramolecular framework based on intermolecular O-H� � �O hydrogen bonds (dashed blue lines) corresponding to entries 2-4 in Table 1.

Synthesis and crystallization
Single crystals of the title complex were unexpectedly obtained in an attempt to substitute the chlorido ligand in [Cu(H 5 bis-tris)Cl] + by a heterocyclic compound.Complex [Cu(H 5 bis-tris)Cl] + Cl À (1 mmol, 0.343 g) and fluconazole (1 mmol, 0.307 g) were dissolved in ethanol (70% v/v solution, 15 ml).The mixture was heated to 323 K under stirring for 20 min, and filtered to eliminate a blue precipitate.The resulting solution was evaporated over 3 days, affording a blue product.The crude product was recrystallized in methanol, giving sky-blue crystals used for the diffraction study (see Fig. 2, inset).

Refinement
Crystal data, data collection and structure refinement details are summarized in Table 2.

Table 2
Experimental details.