Substituent effects at nitrogen/phosphorus atoms of dialkaline earth metal complexes: Excess electron and large second‐hyperpolarizability

A number of Λ shaped complexes of alkaline earth metals Be , Mg and Ca with varying terminal groups have been considered for the theoretical study of their second hyperpolarizability. The chosen complexes are found to be sufficiently stable and for a chosen ligand the stability decreases in the order: Be -complex > Ca -complex > Mg -complex. The calculated results of second hyperpolarizability obtained at different DFT functionals for the 6-311++G(d,p) basis set are found to be fairly consistent. The Λ shaped ligands upon complex formation with metals lead to strong enhancement of second hyperpolarizability. The highest magnitude of cubic polarizability has been predicted for the metal complex having > C ( C 2 H 5)2 group. For a chosen ligand, the magnitude of second hyperpolarizability increases in the order Be -complex < Mg -complex < Ca -complex which is the order of increasing size and electropositive character of the metal. The variation of second hyperpolarizability among the investigated metal complexes has been explained in terms of the transition energy and transition moment associated with the most intense electronic transition.

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Chemistry of Unsymmetrical C1-Substituted Oxabenzonorbornadienes

Current Organic Synthesis ◽

10.2174/1570179417666210105121115 ◽

2021 ◽

Vol 17 ◽

Author(s):

Austin Pounder ◽

Angel Ho ◽

Matthew Macleod ◽

William Tam

Keyword(s):

Transition Metal ◽

Metal Complexes ◽

Transition Metal Complexes ◽

Substituent Effects ◽

Face Selectivity ◽

Transition Metal Catalyzed ◽

Catalyzed Reactions ◽

Metal Catalyzed ◽

Synthetic Intermediate

: Oxabenzonorbornadiene (OBD) is a useful synthetic intermediate which can be readily activated by transition metal complexes with great face selectivity due to its dual-faced nature and intrinsic angle strain on the alkene. To date, the understanding of transition-metal catalyzed reactions of OBD itself has burgeoned; however, this has not been the case for unsymmetrical OBDs. Throughout the development of these reactions, the nature of C1-substituent has proven to have a profound effect on both the reactivity and selectivity of the outcome of the reaction. Upon substitution, different modes of reactivity arise, contributing to the possibility of multiple stereo-, regio-, and in extreme cases, constitutional isomers which can provide unique means of constructing a variety of synthetically useful cyclic frameworks. To maximize selectivity, an understanding of bridgehead substituent effects is crucial. To that end, this review outlines hitherto reported examples of bridgehead substituent effects on the chemistry of unsymmetrical C1-substituted OBDs.

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Alkali and Alkaline Earth Metal Complexes as Versatile Catalysts for Ring‐Opening Polymerization of Cyclic Esters

The Chemical Record ◽

10.1002/tcr.202100148 ◽

2021 ◽

Author(s):

Jayeeta Bhattacharjee ◽

Alok Sarkar ◽

Tarun K. Panda

Keyword(s):

Metal Complexes ◽

Ring Opening ◽

Alkaline Earth ◽

Earth Metal ◽

Ring Opening Polymerization ◽

Alkaline Earth Metal ◽

Cyclic Esters

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C–H and C–F coordination of arenes in neutral alkaline earth metal complexes

Dalton Transactions ◽

10.1039/d1dt01532j ◽

2021 ◽

Author(s):

Jacob S. McMullen ◽

Alison J. Edwards ◽

Jamie Hicks

Keyword(s):

Metal Complexes ◽

Alkaline Earth ◽

Earth Metal ◽

Alkaline Earth Metal ◽

Calcium Complexes ◽

Group 2 ◽

Rare Group

A series of neutral magnesium and calcium complexes bearing an extremely bulky diamido ligand have been synthesised and crystallographically characterised. A number of these complexes feaure rare group 2 metal···aromatic...

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