An unusual carbon-carbon bond cleavage in bulky metal alkoxides: syntheses and x-ray crystal structures of three-coordinate manganese(II) and chromium(II) complexes containing the di-tert-butylmethoxide ligand

1985 ◽  
Vol 107 (1) ◽  
pp. 169-173 ◽  
Author(s):  
Brendan D. Murray ◽  
Haakon Hope ◽  
Philip P. Power

1986 ◽  
Vol 39 (11) ◽  
pp. 1811 ◽  
Author(s):  
JR Cannon ◽  
VA Patrick ◽  
AH White

The crystal structures of 1,1,2,2-tetrabenzoylethane (3), 1,2-diacetyl- 1,2-dibenzoylethane (4) and 1,1,2,2-tetraethoxycarbonylethane (tetraethyl ethanetetracarboxylate ) (5) have been determined by X-ray diffraction from diffractometer data at 295 K and were refined by least-squares techniques to residuals of 0.050 (1077 'observed' reflections), 0.056 (3020) and 0.041 (480), respectively. Crystals of (3) are triclinic, Pī , Z 1, a 6.145(2), b 9.002(3), c 11.261(3) Ǻ; α 101.91(3), β 91.88(3), γ 105.94(3)°. Crystals of (4) are also triclinic, Pī , Z 2, a 17.119(5), b 7.210(1), c 7.175(2) Ǻ, α 89.59(2), β 72.92(2), γ 87.87(2)°. Crystals of (5) are tetragonal, P42/n, Z 4, a 17.748(6), c 5.515(1)Ǻ. In the solid state each compound exists in the keto form which adopts the antiperiplanar conformation about the central carbon-carbon bond.



1970 ◽  
Vol 43 (5) ◽  
pp. 1530-1534 ◽  
Author(s):  
Akio Nishimura ◽  
Masaki Ohta ◽  
Hiroshi Kato


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Longfei Lin ◽  
Mengtian Fan ◽  
Alena M. Sheveleva ◽  
Xue Han ◽  
Zhimou Tang ◽  
...  

AbstractOptimising the balance between propene selectivity, propene/ethene ratio and catalytic stability and unravelling the explicit mechanism on formation of the first carbon–carbon bond are challenging goals of great importance in state-of-the-art methanol-to-olefin (MTO) research. We report a strategy to finely control the nature of active sites within the pores of commercial MFI-zeolites by incorporating tantalum(V) and aluminium(III) centres into the framework. The resultant TaAlS-1 zeolite exhibits simultaneously remarkable propene selectivity (51%), propene/ethene ratio (8.3) and catalytic stability (>50 h) at full methanol conversion. In situ synchrotron X-ray powder diffraction, X-ray absorption spectroscopy and inelastic neutron scattering coupled with DFT calculations reveal that the first carbon–carbon bond is formed between an activated methanol molecule and a trimethyloxonium intermediate. The unprecedented cooperativity between tantalum(V) and Brønsted acid sites creates an optimal microenvironment for efficient conversion of methanol and thus greatly promotes the application of zeolites in the sustainable manufacturing of light olefins.



Author(s):  
Xiangtai Meng ◽  
Dengfeng Chen ◽  
Rui Liu ◽  
Ping Jiang ◽  
Shenlin Huang




2014 ◽  
Vol 16 (3) ◽  
pp. 804-807 ◽  
Author(s):  
Nagnath Yadav More ◽  
Masilamani Jeganmohan


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