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Selected papers from the latest issue:Energy decomposition analysis of the metal-imine bond in [(CO)4M-SB] (M = Cr, Mo, W; SB: RHC=N−CH2CH2−N=CHR)
26 October 2011, 21:40:14
Publication year: 2011
Source: Journal of Organometallic Chemistry, Available online 25 October 2011
Mehdi Bayat, Sadegh Salehzadeh, Gernot Frenking
The electronic and molecular structures of the metal-Schiff base complexes [(CO)4M-SB] (M: Cr, Mo, W; SB: RHC=N−CH2CH2−N=CHR, R = C6H5, C6F5,Ortho-, Meta- and Para-XC6H4(X = F, Cl, Br,CH3)) have been investigated at the DFT level using the exchange correlation functional BP86. The nature of the TM−Schiff base interactions was analyzed with charge and energy decomposition methods. The octahedral equilibrium geometries have C2vsymmetry. The (CO)4M-SB bond dissociation energies vary little for different substituents R. The calculated values indicate rather strong bonds which exhibit the trend for the different metals M = Mo (De= 59.8 – 65.4 kcal/mol) < Cr (De= 62.3 – 67.8 kcal/mol) < W (De= 69.9 – 75.8 kcal/mol). The energy decomposition analysis suggests that the (CO)4M-SB attractive interactions come mainly from electrostatic attraction which provide ∼60% to ∆Eintwhile ∼40% come from orbital interactions. The latter term arises mainly (∼70%) through (CO)4M←SB σ donation from the nitrogen lone-pair orbitals while a much smaller part (∼20%) comes from (CO)4M→SB π backdonation. The transition metals carry large negative partial charges between -2.3 e for M = Cr and -1.1e for M = W.
Source: Journal of Organometallic Chemistry, Available online 25 October 2011
Mehdi Bayat, Sadegh Salehzadeh, Gernot Frenking
The electronic and molecular structures of the metal-Schiff base complexes [(CO)4M-SB] (M: Cr, Mo, W; SB: RHC=N−CH2CH2−N=CHR, R = C6H5, C6F5,Ortho-, Meta- and Para-XC6H4(X = F, Cl, Br,CH3)) have been investigated at the DFT level using the exchange correlation functional BP86. The nature of the TM−Schiff base interactions was analyzed with charge and energy decomposition methods. The octahedral equilibrium geometries have C2vsymmetry. The (CO)4M-SB bond dissociation energies vary little for different substituents R. The calculated values indicate rather strong bonds which exhibit the trend for the different metals M = Mo (De= 59.8 – 65.4 kcal/mol) < Cr (De= 62.3 – 67.8 kcal/mol) < W (De= 69.9 – 75.8 kcal/mol). The energy decomposition analysis suggests that the (CO)4M-SB attractive interactions come mainly from electrostatic attraction which provide ∼60% to ∆Eintwhile ∼40% come from orbital interactions. The latter term arises mainly (∼70%) through (CO)4M←SB σ donation from the nitrogen lone-pair orbitals while a much smaller part (∼20%) comes from (CO)4M→SB π backdonation. The transition metals carry large negative partial charges between -2.3 e for M = Cr and -1.1e for M = W.
Highlights
► The (CO)4M-SB bond dissociation energies vary little for different SB ligands. ► The M-SB interactions come mainly from electrostatic attraction ( ∼60% to ∆Eint). ► The transition metals, specially Cr atom, carry large negative partial charges.Order-disorder phase transition with associated cell-tripling in the (octamethylferrocene)(2,3-dichloro-1,4-naphthoquinone)2charge-transfer complex
26 October 2011, 21:40:14
Publication year: 2011
Source: Journal of Organometallic Chemistry, Available online 25 October 2011
Yusuke Funasako, Tomoyuki Mochida, Kenji Yoza
The structural change associated with the first-order phase transition (TC= 155.1 K) in a mixed-stack charge-transfer complex (octamethylferrocene)(2,3-dichloro-1,4-naphthoquinone)2was investigated crystallographically. X-ray structure determination at 90 K revealed that the transition is associated with the order-disorder of the C5Me4H ring in octamethylferrocene. In the low temperature phase, tripling of the unit cell occurred, accompanied by a change in spacegroup fromP21/c toP−1, and every third octamethylferrocene molecule twists out of the plane to minimize steric interactions.
The structural change associated with the first-order phase transition (TC= 155.1 K) in a mixed-stack charge-transfer complex (octamethylferrocene)(2,3-dichloro-1,4-naphthoquinone)2was investigated crystallographically. X-ray structure determination at 90 K revealed that the transition is associated with the order-disorder of the C5Me4H ring in octamethylferrocene. In the low temperature phase, tripling of the unit cell occurred, accompanied by a change in spacegroup fromP21/c toP−1, and every third octamethylferrocene molecule twists out of the plane to minimize steric interactions.
Source: Journal of Organometallic Chemistry, Available online 25 October 2011
Yusuke Funasako, Tomoyuki Mochida, Kenji Yoza
The structural change associated with the first-order phase transition (TC= 155.1 K) in a mixed-stack charge-transfer complex (octamethylferrocene)(2,3-dichloro-1,4-naphthoquinone)2was investigated crystallographically. X-ray structure determination at 90 K revealed that the transition is associated with the order-disorder of the C5Me4H ring in octamethylferrocene. In the low temperature phase, tripling of the unit cell occurred, accompanied by a change in spacegroup fromP21/c toP−1, and every third octamethylferrocene molecule twists out of the plane to minimize steric interactions.
The structural change associated with the first-order phase transition (TC= 155.1 K) in a mixed-stack charge-transfer complex (octamethylferrocene)(2,3-dichloro-1,4-naphthoquinone)2was investigated crystallographically. X-ray structure determination at 90 K revealed that the transition is associated with the order-disorder of the C5Me4H ring in octamethylferrocene. In the low temperature phase, tripling of the unit cell occurred, accompanied by a change in spacegroup fromP21/c toP−1, and every third octamethylferrocene molecule twists out of the plane to minimize steric interactions.
Highlights
► The low temperature structure of (octamethylferrocene)(2,3-dichloro-1,4-naphthoquinone)2was determined by crystallography.►An order-disorder phase transition was accompanied by ring ordering and cell tripling.►A Structural change occurred and was caused by steric interactions between the donors and acceptors.Efficient Transfer Hydrogenation Reaction Catalyzed by A Dearomatized PNP Ruthenium Pincer Complex Under Base-Free Conditions
24 October 2011, 02:44:44
Publication year: 2011
Source: Journal of Organometallic Chemistry, Available online 22 October 2011
Li-Peng He, Tao Chen, Dong-Xu Xue, Mohamed Eddaoudi, Kuo-Wei Huang
A dearomatized complex [RuH(PNP)(CO)] (PNP=N,N'-bis(di-tert-butylphosphino)-2,6-diaminopyridine) (3) was prepared by reaction of the aromatic complex [RuH(Cl)(PNP)(CO)] (2) witht-BuOK in THF. Further treatment of3with formic acid led to the formation of a rearomatized complex (4). These new complexes were fully characterized and the molecular structure of complex4was further confirmed by X-ray crystallography. In complex4, a distorted square-pyramidal geometry around the ruthenium center was observed, with the CO ligandtransto the pyridinic nitrogen atom and the hydride located in the apical position. The dearomatized complex3displays efficient catalytic activity for hydrogen transfer of ketones in isopropanol.
A dearomatized PNP-Ru pincer complex (3) efficiently catalyzes transfer hydrogenation of ketones withi-PrOH via metal-ligand cooperation
Source: Journal of Organometallic Chemistry, Available online 22 October 2011
Li-Peng He, Tao Chen, Dong-Xu Xue, Mohamed Eddaoudi, Kuo-Wei Huang
A dearomatized complex [RuH(PNP)(CO)] (PNP=N,N'-bis(di-tert-butylphosphino)-2,6-diaminopyridine) (3) was prepared by reaction of the aromatic complex [RuH(Cl)(PNP)(CO)] (2) witht-BuOK in THF. Further treatment of3with formic acid led to the formation of a rearomatized complex (4). These new complexes were fully characterized and the molecular structure of complex4was further confirmed by X-ray crystallography. In complex4, a distorted square-pyramidal geometry around the ruthenium center was observed, with the CO ligandtransto the pyridinic nitrogen atom and the hydride located in the apical position. The dearomatized complex3displays efficient catalytic activity for hydrogen transfer of ketones in isopropanol.
A dearomatized PNP-Ru pincer complex (3) efficiently catalyzes transfer hydrogenation of ketones withi-PrOH via metal-ligand cooperation
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