Gehinderte Ligandenbewegungen in Übergangsmetallkomplexen, VI Darstellung von cis-Tetracarbonyl-trimethylphosphin-olefin-wolfram(0)-Komplexen und Nachweis einer gehinderten Olefinrotation / Hindered Ligand Motions in Transition Metal Complexes, VI Synthesis of cis-Tetracarbonyl-trimethylphosphine-olefin-tungsten(0) Complexes and Proof of a Hindered Olefin Rotation

1975 ◽  
Vol 30 (9-10) ◽  
pp. 748-750 ◽  
Author(s):  
Cornelius G. Kreiter ◽  
Hans Strack
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Fumaric Acid ◽  
Dimethyl Ester ◽  
Double Bonds ◽  
Hindered Rotation ◽  
Acid Dimethyl Ester

cis-Tetracarbonyl-trimethylphosphine-olefin-tungsten(0) complexes (olefin = maleic and fumaric acid dimethyl ester, ethylene) were synthesized to study the hindered rotation of the olefin ligands. The favourable orientations of the coordinated C-C double bonds with respect to the coordination octahedron were determined.

Recent Advances in Transition Metal Catalyzed C-H Functionalization Reactions Involving Aza/Oxabicyclic Alkenes

Synthesis ◽  
2021 ◽  
Author(s):  
Masilamani Jeganmohan ◽  
Pinki Sihag
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Ring Opening ◽  
Bond Activation ◽  
Considerable Progress ◽  
Double Bonds ◽  
Facial Selectivity ◽  
Ring Opening Reactions ◽  
Metal Catalyzed

Bicyclic alkenes, including Oxa- and azabicyclic alkenes can be readily activated by using transition-metal complexes with facial selectivity, because of the intrinsic angle strain on carbon-carbon double bonds of these unsymmetrical bicyclic systems. During last decades considerable progress has been done in the area of ring-opening of bicyclic strained ring by employing the concept of C-H activation. This Review comprehensively compiles the various C-H bond activation assisted reactions of oxa- and azabicyclic alkenes, viz., ring-opening reactions, hydroarylation as well as annulation reactions.

Gehinderte Ligandbewegungen in Übergangsmetallkomplexen, XLIV [1]: Photoreaktionen von Hexacarbonyl-μ-η5:5-fulvalen-dimolybdän mit Allen / Hindered Ligand Movements in Transition Metal Complexes, XLIV [1]: Photoreactions of Hexacarbonyl-μ-η5:5 -fulvalene-dimolybdenum with Allene

1994 ◽  
Vol 49 (12) ◽  
pp. 1707-1716 ◽  
Author(s):  
Cornelius G. Kreiter ◽  
Wolfgang Conrad
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Uv Irradiation ◽  
Energy Barrier ◽  
Room Temperature ◽  
The Other ◽  
Hindered Rotation ◽  
Activation Barriers

Hexacarbonyl-μ-η5:5-fulvalene-dimolybdenum (1) reacts photochemically with allene to η2-allene-pentacarbonyl-μ-η5:5-fulvalene-dimolybdenum (2), μ-η2:2-allene-tetracarbonyl- μ-η5:5-fulvalene-dimolybdenum (4), and dicarbonyl-μ-η5:5-fulvalene-μ-η1:2:3-2-methylene- 4-penten-1,4-diyl-dimolybdenum (5). Complex 2 rearranges readily at room temperature to pentacarbonyl-μ-η1:3-2-propen-1,2-diyl-μ-η5:5-fulvalene-dimolybdenum (3). Upon UV irradiation 4 yields with an excess of allene μ-η2:2-Allene-pentacarbonyl-μ-η5:5-fulvalene-dimolyb-denum (2) shows a hindered rotation of the allene ligand with an energy barrier of ⊿G#303 = 53.3 ± 2 kJ/mol. Hexacarbonyl-μ-η5:5-bis(cyclopentadiendiyl)methane-dimolybdenum (6) reacts with allene to μ-η2:2-ailene-tetracarbonyl-μ-η5:5-bis(cyclopentadiendiyl)methane- dimolybdenum (7) and octacarbonyl-bis{μ-η5:5:1-(cyclopentadiendiyl-cyclopentadientriyl)-methanejdihydrido-tetramolybdenum (8). For μ-η2:2-allene-tetracarbonyl-μ-η5:5-fulvalene-dimolybdenum (4) and 7 a hindered ligand movement was detected, by which the bridging allene ligand changes from one the side of the molecule to the other. The activation barriers of these pseudo rotations were determined for 4 with ⊿G#303 = 57.4 ± 2 kJ/mol and for 7 with ⊿G#293 = 63.4 ± 2 kJ/mol. Hexacarbonyl-μ-η5:5-fulvalene-ditungsten, hexacarbonyl-μ-η5-bis(cyclopentadiendiyl)ethane-dimolybdenum and hexacarbonyl-μ-η5:5-bis(cyclopen- tadiendiyl)propane-dimolybdenum form no stable photoproducts with allene.

Mechanochemical changes on cyclometalated Ir(iii) acyclic carbene complexes – design and tuning of luminescent mechanochromic transition metal complexes

2020 ◽  
Vol 7 (3) ◽  
pp. 786-794 ◽  
Author(s):  
Jingqi Han ◽  
Kin-Man Tang ◽  
Shun-Cheung Cheng ◽  
Chi-On Ng ◽  
Yuen-Kiu Chun ◽  
...  
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Carbene Complexes ◽  
New Class

A new class of luminescent cyclometalated Ir(iii) complexes with readily tunable mechanochromic properties derived from the mechanically induced trans-to-cis isomerization have been developed.

Density Functional Calculations of EPR Parameter g Tensors of Some Transition Metal Complexes

2011 ◽  
Vol 2 (2) ◽  
pp. 139-141
Author(s):  
Vinita Prajapati ◽  
◽  
P.L.Verma P.L.Verma ◽  
Dhirendra Prajapati ◽  
B.K.Gupta B.K.Gupta
Keyword(s):  
Transition Metal ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Density Functional Calculations ◽  
Density Functional

Synthesis, Characterization and in vitro Biological Evaluation of a New Schiff Base Derived from Drug and its Complexes with Transition Metal Ions

2018 ◽  
Vol 69 (7) ◽  
pp. 1678-1681
Author(s):  
Amina Mumtaz ◽  
Tariq Mahmud ◽  
M. R. J. Elsegood ◽  
G. W. Weaver
Keyword(s):  
Schiff Base ◽  
Transition Metal ◽  
Metal Ions ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Free Ligand ◽  
Transition Metal Ions ◽  
Biological Evaluation ◽  
Pyridoxal Hydrochloride

New series of copper (II), cobalt (II), zinc (II), nickel (II), manganese (II), iron (II) complexes of a novel Schiff base were prepared by the condensation of sulphadizine and pyridoxal hydrochloride. The ligand and metal complexes were characterized by utilizing different instrumental procedures like microanalysis, thermogravimetric examination and spectroscopy. The integrated ligand and transition metal complexes were screened against various bacteria and fungus. The studies demonstrated the enhanced activity of metal complexes against reported microbes when compared with free ligand.

DNA Binding Mode of Transition Metal Complexes, A Relationship to Tumor Cell Toxicity

2014 ◽  
Vol 21 (26) ◽  
pp. 3081-3094 ◽  
Author(s):  
M. Ashfaq ◽  
T. Najam ◽  
S.S.A. Shah ◽  
M.M. Ahmad ◽  
S. Shaheen ◽  
...  
Keyword(s):  
Dna Binding ◽  
Transition Metal ◽  
Tumor Cell ◽  
Metal Complexes ◽  
Transition Metal Complexes ◽  
Binding Mode ◽  
Cell Toxicity
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