[Show abstract][Hide abstract] ABSTRACT: (Z)-1,2-Di(1-pyrenyl)disilene containing bulky 1,1,3,3,5,5,7,7-octaethyl-s-hydrindacen-4-yl (Eind) groups has been obtained as purple crystals by the reductive coupling reaction of the corresponding dibromosilane with lithium naphthalenide. An X-ray crystallographic analysis revealed an Eind- and pyrenyl-meshed molecular gear around the disilene core adopting the Z configuration, in which the two pyrenyl groups intramolecularly interact through the π-π stacking with a distance of 3.635 Å between the centers of the two pyrene rings. The disilene π-system exhibits a 3pπ(Si-Si)→2pπ*(pyrene) intramolecular charge-transfer (ICT) fluorescence at room temperature, whose wavelengths depend on the solvent polarity. The photophysical properties are theoretically supported by computational studies including excited-state calculations.
No preview · Article · Jan 2016 · Journal of the American Chemical Society
[Show abstract][Hide abstract] ABSTRACT: Diphosphenes stabilized by the fused-ring bulky 1,1,3,3,5,5,7,7-octa-R-substituted s-hydrindacen-4-yl (Rind) groups have been obtained as orange crystals by the reduction of the corresponding dichlorophosphines, (Rind)PCl2, with lithium naphthalenide (LiNaph). The molecular structures of (Eind)PCl2 and the diphosphenes, (Eind)PP(Eind) and (EMind)PP(EMind), having the bulky Eind and the less bulky EMind groups, have been confirmed by X-ray crystallography. The formation of the PP bond has been fully characterized by spectroscopic methods.
No preview · Article · Nov 2014 · Heteroatom Chemistry
[Show abstract][Hide abstract] ABSTRACT: A series of octa-R-substituted bromo-s-hydrindacenes, "Rind-Br," have been synthesized by a sequence of the Lewis acid catalyzed intramolecular Friedel-Crafts reaction, bromination and vice versa. Their structural features and physical properties depend on the eight R-substituents at the four benzylic positions on the s-hydrindacenyl skeleton. The molecular structures of the Rind-Br have been confirmed by X-ray crystallography, indicating the unique structural diversities of the bulky Rind groups.
No preview · Article · Oct 2011 · Bulletin of the Chemical Society of Japan
[Show abstract][Hide abstract] ABSTRACT: A series of neutral and cationic Au(I) complexes incorporating π-conjugated phosphasilene ligands stabilized by the bulky 1,1,3,3,5,5,7,7-octa-R-substituted s-hydrindacen-4-yl (Rind) groups have been synthesized. X-ray crystallographic studies show the η1-coordination mode of the phosphasilene ligand, accommodating the linear trans two-coordinate geometry around the gold center. While the metal coordination slightly enhances the intensity of the strong π–π* absorption of the phosphasilene chromophores, the phosphashilene π-conjugation is not extended through the Au atom.
[Show abstract][Hide abstract] ABSTRACT: Recent progress in the chemistry of π-conjugated phosphasilenes stabilized by bulky protecting groups based on a fused-ring octa-R-substituted s-hydrindacene skeleton (Rind groups) is reviewed. The phosphasilenes with a variety of aryl substituents at the silicon atom are covered in detail. The X-ray crystallography analysis showed the highly coplanar π-framework reinforced by the perpendicularly-fixed Rind groups. Strong π–π* absorptions have been observed, demonstrating the extension of π-conjugation over the skeleton. The DFT calculations indicated that the LUMO involves significant contribution by the 3pπ*(Si–P)–2pπ*(carbon π-electron system) conjugation. The preparation of the gold(I) complexes of the π-conjugated phosphasilenes is also included.
[Show abstract][Hide abstract] ABSTRACT: Pi-conjugated phosphasilenes with a variety of aryl substituents on the silicon atom have been synthesized by the use of a 1,1,3,3,5,5,7,7-octaethyl-s-hydrindacen-4-yl (Eind) group. X-ray structural analysis shows the highly coplanar pi-framework stabilized by the perpendicularly fixed Eind groups. The strong pi-pi* absorptions have been observed, demonstrating the extension of pi-conjugation over the skeleton. The DFT calculations indicate that the LUMO involves the substantial contribution of the 3p(pi)*(Si-P)-2p(pi)*(carbon pi-electron system) conjugation. The electrochemical properties of the phosphasilens are also presented.
No preview · Article · Sep 2009 · Journal of the American Chemical Society