Tetra(o-phenyldiazo-p-methylphenoxy)silane – A silicon complex with a fourfold capped-tetrahedral [4+4] coordination sphere

Gerlach, Daniela; Wagler, Jörg

doi:10.1016/j.inoche.2007.05.005

Cited by 9 publications

(3 citation statements)

References 12 publications

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“…Preparation of the azoderivatives 4-Hydroxyazobenzene (4-OH), 23 4-hydroxy-4 0 -methoxyazobenzene (4-OH-4 0 -OMe), 24 2-hydroxy-5-methylazobenzene (2-OH), 25 2-hydroxy-4 0 -methoxy-5-methylazobenzene (2-OH-4 0 -OMe), 24 2,4-dihydroxyazobenzene (2,4-OH) 26 and 4-hydroxy-2 0 ,4 0 -dimethoxyazobenzene (4-OH-2 0 ,4 0 -OMe) 26 were prepared from aniline, 4-methoxyaniline or 2,4dimethoxyaniline by coupling the respective diazonium salt with phenol, 4-methylphenol or resorcinol in basic media at 0-5 1C, as reported previously. 4,4 0 -Dihydroxyazobenzene (4,4 0 -OH), 27 2,4 0 -dihydroxy-5-methylazobenzene (2,4 0 -OH) and 2,4,4 0 -trihydroxyazobenzene (2,4,4 0 -OH) 28 were obtained by cleaving the methyl ether of 4-OH-4 0 -OMe, 2-OH-4 0 -OMe and 4-OH-2 0 ,4 0 -OMe, respectively, with BBr 3 in dry CH 2 Cl 2 at room temperature.…”

Section: Materials and General Instrumentationmentioning

confidence: 99%

Kinetic study of the fast thermal cis-to-trans isomerisation of para-, ortho- and polyhydroxyazobenzenes

García-Amorós

Sánchez‐Ferrer

Massad

et al. 2010

Phys. Chem. Chem. Phys.

109

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The thermal cis-to-trans isomerisation process has been studied for a series of para-, ortho- and polyhydroxy-substituted azobenzenes in different solvents. The kinetics of the thermal back reaction for the p-hydroxy-substituted azobenzenes depend strongly on the nature of the solvent used, with relaxation times ranging from 200-300 milliseconds in ethanol to half an hour in toluene. Otherwise, the process rate is mainly independent of the solvent nature for the ortho substituted analogues. Polyhydroxy-substituted azobenzenes show very much faster kinetics than the para- and ortho- monohydroxyazoderivatives. With relaxation times of 6-12 milliseconds in ethanol, they are optimal molecules for designing fast optical switching devices. All the hydroxyazoderivatives thermally isomerise from the metastable cis form to the thermodynamically stable trans isomer through a rotational mechanism.

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Section: Materials and General Instrumentationmentioning

confidence: 99%

Kinetic study of the fast thermal cis-to-trans isomerisation of para-, ortho- and polyhydroxyazobenzenes

García-Amorós

Sánchez‐Ferrer

Massad

et al. 2010

Phys. Chem. Chem. Phys.

109

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“…The silicon coordination spheres are [4+ n ]-capped tetrahedral, n being the number of 7-azaindolyl groups. The capping Si···N separations, which range between 3.09 and 3.22 Å, are slightly shorter than the corresponding Al···N separations in related aluminum compounds (e.g., 3.26 Å in Al L 3 ( L H) ), and they are similar to those observed for a 4-fold-capped SiO 4 -coordination sphere with diazobenzene N atoms as the capping lone-pair donors (3.07–3.12 Å) . Interestingly, crystal packing effects seem to dominate the molecular conformation of the 7-azaindolylsilanes, because cappings of tetrahedral faces opposite Si–N (in MeSi L 3 ) and Si–C bonds (in Me 2 Si L 2 ) are observed.…”

Section: Resultsmentioning

confidence: 55%

“…07−3.12 Å) 6. Interestingly, crystal packing effects seem to dominate the molecular conformation of the 7-azaindolylsilanes, because cappings of tetrahedral faces opposite Si−N (in MeSiL 3 ) and Si−C bonds (in Me 2 SiL 2 ) are observed.…”

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confidence: 99%

7-Azaindol-1-yl(organo)silanes and Their PdCl₂ Complexes: Pd-Capped Tetrahedral Silicon Coordination Spheres and Paddlewheels with a Pd–Si Axis

et al. 2014

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Supported by excess triethylamine, 7-azaindole (H L ) and dichlorodimethylsilane (Me2SiCl2), methyltrichlorosilane (MeSiCl3), and tetrachlorosilane (SiCl4) react, respectively, with formation of the 7-azaindol-1-yl-substituted silanes Me 2 Si L 2 , MeSi L 3 , and Si L 4 . In these compounds the silicon atom adopts [4+2], [4+3], and [4+4] coordination, respectively, with the pyridine N atoms of the 7-azaindol-1-yl groups capping the tetrahedral Si coordination sphere from distances of >3 Å. Two pyridine nitrogen atoms of these silanes replace the acetonitrile ligands of [PdCl2(NCMe)2], thus forming the complexes Me 2 Si( μ-L ) 2 PdCl 2 , MeSi L ( μ-L ) 2 PdCl 2 , and Si L 2 ( μ-L ) 2 PdCl 2 . In addition to capping of the silicon coordination sphere by the pyridine N atoms of the dangling 7-azaindol-1-yl groups (in MeSi L ( μ-L ) 2 PdCl 2 and Si L 2 ( μ-L ) 2 PdCl 2 ), these three palladium complexes exhibit capping of one tetrahedral face of the Si coordination sphere by the palladium atom (with Si···Pd separations of 3.34, 3.43, and 3.31 Å, respectively). According to computational analyses, the paddlewheel complex ClSi( μ-L ) 4 PdCl should be energetically favored over its isomer Si L 2 ( μ-L ) 2 PdCl 2 ; however, isomerization into this paddlewheel compound requires higher temperatures (150 °C) or the addition of a Lewis acid (such as GaCl3).

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Hypercoordinate Silicon Complexes of (O,N,N′ vs. O,N,O′) Schiff Base Type N‐(2‐Carbamidophenyl)imines: Examples of Exclusively O‐Silylated Carbamides

2009

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Tridentate salphen‐type O,N,N′ chelators, upon acylation of the NH2 group, are capable of engaging an O,N,O′ coordination mode in addition to their inherent O,N,N′ donor character. In six‐coordinate silicon complexes of the type SiL2 [L = N‐(2‐carbamidophenyl)imine], these ligands were found to exclusively form SiN2O4 coordination spheres by engaging their tridentate O,N,O′ donor capability. Selected ligands L were also shown to preferably engage the O,N,O′ coordination mode when incorporated in five‐ and four‐coordinate silicon compounds of the type LSiPhX (X = Cl, F) and LSiPh2, respectively. The coordination modes of the herein presented six‐, five‐, and four‐coordinate silicon compounds represent the first examples of X‐ray structurally confirmed O‐silylated carbamides, which hence adopt structural features of C‐siloxyimines.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)

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Tetra(o-phenyldiazo-p-methylphenoxy)silane – A silicon complex with a fourfold capped-tetrahedral [4+4] coordination sphere

Cited by 9 publications

References 12 publications

Kinetic study of the fast thermal cis-to-trans isomerisation of para-, ortho- and polyhydroxyazobenzenes

Kinetic study of the fast thermal cis-to-trans isomerisation of para-, ortho- and polyhydroxyazobenzenes

7-Azaindol-1-yl(organo)silanes and Their PdCl₂ Complexes: Pd-Capped Tetrahedral Silicon Coordination Spheres and Paddlewheels with a Pd–Si Axis

Hypercoordinate Silicon Complexes of (O,N,N′ vs. O,N,O′) Schiff Base Type N‐(2‐Carbamidophenyl)imines: Examples of Exclusively O‐Silylated Carbamides

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Tetra(o-phenyldiazo-p-methylphenoxy)silane – A silicon complex with a fourfold capped-tetrahedral [4+4] coordination sphere

Cited by 9 publications

References 12 publications

Kinetic study of the fast thermal cis-to-trans isomerisation of para-, ortho- and polyhydroxyazobenzenes

Kinetic study of the fast thermal cis-to-trans isomerisation of para-, ortho- and polyhydroxyazobenzenes

7-Azaindol-1-yl(organo)silanes and Their PdCl2 Complexes: Pd-Capped Tetrahedral Silicon Coordination Spheres and Paddlewheels with a Pd–Si Axis

Hypercoordinate Silicon Complexes of (O,N,N′ vs. O,N,O′) Schiff Base Type N‐(2‐Carbamidophenyl)imines: Examples of Exclusively O‐Silylated Carbamides

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7-Azaindol-1-yl(organo)silanes and Their PdCl₂ Complexes: Pd-Capped Tetrahedral Silicon Coordination Spheres and Paddlewheels with a Pd–Si Axis