rac-2,2′-Bis(diphenylphosphanyl)-1,1′-binaphthyl: a racemic diphosphine ligand

Abstract

The asymmetric unit of the title compound, C44H32P2, conventionally abbreviated BINAP, is one half of the complete chiral BINAP mol­ecule, which adopts a C2 crystallographic point-group symmetry with a twofold axis splitting the mol­ecule in two identical halves; a center of symmetry between mol­ecules further determines the racemic pairs. There are no obvious supra­molecular inter­actions between adjacent BINAP mol­ecules.

4, 4′‐ and 5, 5′‐Functionalized (S)‐ and (R)‐2, 2′‐Bis(diphenylphosphanyl)‐1, 1′‐binaphthyl Oxide Derivatives

“…The two structures are enantiomorphous, crystallize in the monoclinic space group C 2 with two molecules in the unit cell and four H 2 O molecules, and are located on a crystallographic C 2 axis (Figure 4). The dihedral angles between the binaphthyl systems of 82.1° for ( S )‐ 6 and 82.4° for ( R )‐ 6 are slightly smaller than in BINAP (calcd: 86–87°,34a,34b XRD: 84.4–88.34°)6c,38 or BINAPO (85.84°) 39…”

1,1′-Biisoquinolines—Neglected Ligands in the Heterocyclic Diimine Family That Provoke Stereochemical Reflections

“…It is instructive to use ligand 6 to illustrate the consequences of coordination. The free ligand is non-planar as a consequence of the interactions between the 2-PPh 2 and 2′-PPh 2 substituents and also between H8 and H8′; this is seen in the solid-state structures of (2 P )- 6 ( P 2 1 ) [ 36 , 37 ] (2 M )- 6 ( P 2 1 ) [ 37 , 38 ] and rac - 6 ( C 2/ c ) [ 37 , 39 ] which have all been reported. In all cases the two aromatic rings of the 1,1′-binaphthalene scaffold are close to orthogonal in the solid state with torsion angles C2–C1–C1′–C2′ in the range 91.536–93.429°.…”