3,3′-Di-tert-butyl-2′-hydroxy-5,5′,6,6′-tetramethylbiphenyl-2-yl benzenesulfonate

In the title compound, C30H38O4S, the hydroxyl group bonded to one phenyl ring and an O atom of the benzenesulfonate group attached to the other phenyl ring of the biphenyl backbone of the structure are involved in an intramolecular O—H⋯O hydrogen bond. The dihedral angle between the planes of the two aromatic rings of the biphenyl unit is 70.4 (2)°.

In the title compound, C 30 H 38 O 4 S, the hydroxyl group bonded to one phenyl ring and an O atom of the benzenesulfonate group attached to the other phenyl ring of the biphenyl backbone of the structure are involved in an intramolecular O-HÁ Á ÁO hydrogen bond. The dihedral angle between the planes of the two aromatic rings of the biphenyl unit is 70.4 (2) .
importance in the development of coordination chemistry related to catalytic applications. These bulky ligands are designed to provide a steric barrier around active metal center for minimizing the side reaction. Bulky binolate ligand, 5,5',6,6'-tetramethyl-3,3'-di-tert-butyl-1,1'-bi-2,2'-phenolate (BIPHEN 2-) has proved to be important in ring-closing metathesis reactions in both its racemic and resolved forms (La et al., 1998). Recently, a series of binolate metal complexes where the metal atoms are Li, Zn and Al have been synthesized, structurally characterized and studied for the catalytic activity of lactide polymerization (Chisholm et al., 2003). Most recently, Wu and his co-workers, (Wu et al., 2008) have also reported the magnesium complexes supported by mono-benzenesulfonylate phenol ligand and these complexes have been demonstrated as efficient initiators to catalyze ring-opening polymerization of lactides. Our group is interested in the synthesis and preparation of monovalent phenol derived from BIPHEN-H 2 . Here, we report the synthesis and crystal structure of the title compound, (I), a potential ligand for the preparation of magnesium and zinc complexes.
The structure of (I) is composed of a biphenyl moiety containing a benzenesulfonate and a hydroxyl group (Fig. 1). The dihedral angle between the planes of the two aromatic rings of the biphenyl unit is 70.4 (2)°. There is an intramolecular O-H···O hydrogen bond between the phenol and benzenesulfonate groups ( Table 1). The distance of O4···H is substantially shorter than the van der Waals distance of 2.77 Å for the O and H distance. However, the distances O4···H and O4···O1 are around 0.3-0.4 Å longer than that found in the other mono-sulfonylated biaryl derivative with an intermolecular hydrogenbonded motif (1.97 Å & 2.795 (2) Å; Solinas et al., 2007).
The resulting filtrate was then dried under vacuum to obtain the white solids (yield: 78 %). The resulting solid was crystallized from a toluene solution to yield colourless crystals of (I).

Refinement
The H atoms were placed in idealized positions and constrained to ride on their parent atoms, with C-H = 0.93 and 0.96 Å allowing U iso (H) = 1.2 and 1.5U eq (C) for aryl and methyl groups, respectively; for hydroxy group, O-H = 0.82 Å and Fig. 1. A view of the molecular structure of (I) with the atomn umbering scheme. Displacement ellipsoids are drawn at the 30% probability level. 3,3'-Di-tert-butyl-2'-hydroxy-5,5',6,6'-tetramethylbiphenyl-2-yl benzenesulfonate Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.
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 > 2sigma(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.