Taiichi Higuchi

Synthesis and structures of E- and Z-phosphaethylenes

Abstract The X-ray analyses of sterically protected E- and Z-2-phenyl-1-(2,4,6-tri-t-butylphenyl) phosphaethylenes (E-1 and Z-1) were carried out and the structures in the crystal are discussed.

X-Ray structure of the α-cyclodextrin–ferrocene (2 : 1) inclusion compound

The crystal structure of the α-cyclodextrin–ferrocene (2 : 1) inclusion compound has been determined by an X-ray analysis which shows that the ferrocene molecule with approximate D5d symmetry is encapsulated by the dimer of the α-cyclodextrins in a tail-to-tail orientation and inclined by 42° relative to the six-fold axes of the α-cyclodextrins of the dimer.

Asymmetric synthesis catalyzed by chiral ferrocenylphosphine-transition metal complexes: IV. Crystal structure of dichloro[N,N-dimethyl-1-[1′,2-bis(diphenylphosphino)ferrocenyl]ethylamine]palladium(II) (PdCl2[BPPFA])

Abstract An X-ray diffraction study of PdCl 2 (BPPFA) (BPPFA = racemic ( S * )- N,N -dimethyl-1-[( R * )-1′,2-bis(diphenylphosphino)ferrocenyl]ethylamine was carried out. The palladium-BPPFA complex has square-planar geometry with two cis chlorine and two phosphorus atoms, and the nitrogen atom which is not bound to palladium. The orientation of the four phenyl groups around the phosphorus atoms is nearly the same as that in its achiral analogue, PdCl 2 (dppf) (dppf = 1,1′-bis(diphenylphosphino)ferrocene). The aminoalkyl side chain on the cyclopentadienyl ring is responsible for fixing the chiral conformation of the palladium-ferrocenylbisphosphine chelate.

Crystal and molecular structure of the γ-cyclodextrin–12-crown-4 1 : 1 inclusion complex

The crystal structure of the γ-cyclodextrin–12-crown-4 1 : 1 inclusion complex has been determined by an X-ray analysis which shows that three γ-cyclodextrins are stacked along a four-fold rotation axis forming a channel-type structure and each γ-cyclodextrin includes a 12-crown-4 molecule in a similar orientation.

The first x-ray structure determination of a z-phosphaethylene: z-2-phenyl-1-(2,4,6-tri-t-butylphenyl)phosphaethylene

Abstract The sterically protected Z -phosphaethylene, Z -2-phenyl-1-(2,4,6-tri-t-butylphenyl)phosphaethylene ( 1-Z ), was analyzed by X-ray crystallography.

X-ray structure of a sterically protected 1-aza-3-phospha-allene

Abstract Sterically protected 1-phenyl—(1) and 1-t-butyl—(2) 3-(2,4,6-tri-t-butylphenyl)-1-aza-3-phospha-allenes were prepared and the X-ray structure was determined for 1; ab initio calculations were carried out for the parent compound, HPCNH.

STRUCTURES OF PHOSPHAETHYLENES AND A 1-PHOSPHAALLENE CONTAINING PHOSPHORUS IN LOWER COORDINATION STATE

Abstract The X-ray analyses of sterically protected Z-2-t-butyldimethylsilyloxy-2-phenylphosphaethylene (Z-2) and 3,3-diphenyl-1-phosphaallene (3) were carried out and the structures of the parent compounds, HP[dbnd]CH2 and HP[dbnd]C[dbnd]CH2, were optimized by ab initio methods.

Reaction of the diphosphene ArPPAr (Ar = 2,4,6-But3C6H2) with sulphur: isolation and X-ray structure of the diphosphene monosulphide

The diphosphene ArPPar (Ar = 2,4,6-But3C6H2) reacts with elemental sulphur to give the stable monosulphide ArP(S)Par (2) whose structure was confirmed by an X-ray analysis; when treated with hexamethylphosphorous triamide, (2) reverts to the starting diphosphene but thermal and photochemical isomerisation of (2) gives the thiadiphosphirane Ar[graphic omitted]Ar.

Triplet Biradicals that are Stable in Crystals

Abstract Three trans-syn- 3,3′-diary1-2,2′-biindenyl-idene-1,1′-diones (2a-c) showed sharp photochromic phenomena in their crystalline forms. By exposure to sunlight, 2a-c were converted to stable biradicals (3a-c). Although N,N′-dimethyl indigo (6) has an almost planar structure, 6 in its 1:1 inclusion crystal with the host 1,1,6,6-tetrapheny1-2,4-hexadiyne-1,6-diol (7) was found to have a twisted structure of dihedral angle 42.6° between the two rings.

Structural study of monosubstituted β-cyclodextrins. Crystal structures of phenylthio-β-cyclodextrin and phenylsulphinyl-β-cyclodextrin and spectroscopic study of related compounds in aqueous solution

The crystal structures of two monosubstituted β-cyclodextrins which have bulky hydrophobic groups instead of primary hydroxy groups were determined by X-ray diffraction. These compounds consist of the host (cyclodextrin moieties) and guest parts (hydrophobic groups), and have the ability to act as both host and guest at the same time. The crystal structures were solved by using Patterson maps, rotation functions, and trial-and-error methods combined with a rigid-body least-squares technique. The structures were refined by using a block-diagonal least-squares method to R values of 0.14 and 0.13. Hydrophobic groups are intermolecularly included in the cyclodextrin cavity of another molecule, and novel helical polymers are formed by repetition of this intermolecular inclusion. A spectroscopic study confirmed that this intermolecular inclusion occurs in aqueous solution.