Revealing the nature of electron correlation in transition metal complexes with symmetry breaking and chemical intuition

2021 ◽  
Vol 154 (19) ◽  
pp. 194109
Author(s):  
James Shee ◽  
Matthias Loipersberger ◽  
Diptarka Hait ◽  
Joonho Lee ◽  
Martin Head-Gordon
2021 ◽  
Author(s):  
James Shee ◽  
Matthias Loipersberger ◽  
Diptarka Hait ◽  
Joonho Lee ◽  
Martin Head-Gordon

The present work provides a useful framework through which theoreticians and practicing computational chemists alike can view electron correlations in transition metal complexes. We present static correlation from the perspective of simple chemical models such as ligand-field and molecular orbital theories, and an analysis of symmetry breaking suggests that it is rarely encountered in thermochemical calculations of realistic transition metal compounds (though we do reveal a few important situations in which it is relevant). The relative complexity of transition metal bonding, relative to that of typical organic compounds, places a larger burden on a theory's treatment of dynamic correlation. After recognizing that simultaneous sigma-donation and pi-backbonding can be viewed as a correlated interaction involving multiple electron pairs, we demonstrate that MP2 and related double hybrid density functionals fail to describe this type of bonding.


2021 ◽  
Author(s):  
James Shee ◽  
Matthias Loipersberger ◽  
Diptarka Hait ◽  
Joonho Lee ◽  
Martin Head-Gordon

The present work provides a useful framework through which theoreticians and practicing computational chemists alike can view electron correlations in transition metal complexes. We present static correlation from the perspective of simple chemical models such as ligand-field and molecular orbital theories, and an analysis of symmetry breaking suggests that it is rarely encountered in thermochemical calculations of realistic transition metal compounds (though we do reveal a few important situations in which it is relevant). The relative complexity of transition metal bonding, relative to that of typical organic compounds, places a larger burden on a theory's treatment of dynamic correlation. After recognizing that simultaneous sigma-donation and pi-backbonding can be viewed as a correlated interaction involving multiple electron pairs, we demonstrate that MP2 and related double hybrid density functionals fail to describe this type of bonding.


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

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.


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

2018 ◽  
Vol 69 (7) ◽  
pp. 1678-1681
Author(s):  
Amina Mumtaz ◽  
Tariq Mahmud ◽  
M. R. J. Elsegood ◽  
G. W. Weaver

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.


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