5,6-Dimethylbenzo[d][1,3]oxatellurole

The title compound represents the first reported example of a [1,3]oxatellurole, prepared in three steps from 3,4-dimethylphenol. Both independent molecules are folded along their Te⋯O axes, with an average angle φ = 25.1° between the Te–C–O planes and the remaining non-hydrogen atoms. A Hirshfeld plot indicates a weak intermolecular interaction between the two tellurium atoms in the asymmetric unit.

The Hirshfeld surface enclosing each of the two independent molecules was calculated with respect to d e , d i and d norm using the Crystal Explorer program (Spackman et al., 2021), where d e and d i represent the nearest distance of external or internal nucleus from a point of interest on the iso-surface.The surfaces of both independent molecules are nearly identical, indicating interactions as bright-red areas on the Hirshfeld surface as shown in Fig. 2. The strongest of these corresponds to the Te1� � �Te2 close contact of 3.7191 (4) A between the tellurium atoms in the two independent molecules (Fig. 1).This compares to 2.7072 (9) A ˚for the representative covalent Te-Te bond of diphenyl ditelluride (Fuller et al., 2010), indicating a relatively weak interaction.A twodimensional fingerprint plot highlighting the reciprocal Te� � �Te contact is shown in Fig. 3: it accounts for 8.8% of the surface area.checkCIF (Spek, 2020) reports a 100% fit for an inversion center in the title structure and suggests space group Pccn.Indeed, the structure can be solved and refined in Pccn with Z 0 = 1, but the R(F) value is 0.18, the ellipsoids are elongated, and there are numerous violations of all three glide-plane absence conditions.The P2 1 2 1 2 refinement yields a local center at 0.740, 0.758, 0.749, offset from the position necessary for Pccn, so it is clear that this is a case of the 'inverse Marsh' situation (Fronczek, 2018), where the structure can be approximately described in a space group of too high symmetry.

Synthesis and crystallization
The title compound was prepared in three steps, starting with 3,4-dimethylphenol and tellurium tetrachloride as outlined in Fig. 4.
Bis(2-hydroxy-4,5-dimethylphenyl) ditelluride: A 100 ml round-bottom flask with magnetic stirring was charged with The Hirshfeld surface of the title compound mapped over d norm .

Figure 3
Two-dimensional fingerprint plot showing the region corresponding to intermolecular Te� � �Te contacts in red.

Figure 1
The asymmetric unit of the title compound with 50% displacement ellipsoids.
2-hydroxy-3,4-dimethyltellurium trichloride (2.13 g, 6 mmol), sodium metabisulfite (3.42 g, 18 mmol), 95% ethanol (2 ml), water (10 ml) and dichloromethane (10 ml).The mixture was stirred for 5 min, during which time it turned dark red.It was subjected to centrifugation to achieve phase separation.The organic phase was collected with a pipette and the solvent evaporated as quickly as feasible under reduced pressure.Red solid, 0.72 g (48%), mp �310 � C (decomposition).The product is stable in solid form but decomposes rapidly in solution with tellurium formation.Consequently, it was not characterized by NMR spectroscopy.

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Figure 4 Synthesis of the title compound. Figure2

Table 1
Experimental details.