Coordination and Organometallic Complexes

Octupolar molecules, instead, may be centrosymmetric but they imply the existence of twofold (D2) or threefold (D3) rotational axes. They are characterized by multidirectional CT excitations. The theoretical description of nonlinearity of such systems implies, even in the simplest case, a three-level approach. The prototypical example of an octupolar molecule is represented by 1,3,5-triamino-2,4,6-trinitrobenzene. 

In fact, as coordination and organometallic complexes may possess intense, low-energy MLCT, ligand-to-metal CT (LMCT), or intraligand CT (ILCT) excitations, the metal can effectively act as the donor, the acceptor, or the polarizable bridge of a donor-acceptor network. Finally, metal ions are well suited to build molecular structures based on octupolar coordination of organic ligands with D2 or D3 symmetry. 

In the following paragraphs is reported an overview, mainly limited to the last 8-10 years, on coordination and organometallic second-order NLO active chromophores, focusing the attention only on specific and relevant aspects associated with each class of NLO chromophores therefore the overview is not exhaustive. 

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Coordination and Organometallic Complexes as Second-order Nonlinear Optical Molecular Materials... 

I present data from our recent experimental and theoretical studies of metal surfaces that implicate the very same sequential steps described above for C-H bond activation in molecular coordination and organometallic complexes. 

Coordination and organometallic complexes of zirconium and hafnium have in recent years shown a rich... 

This work provides a relatively comprehensive review of studies involving ruthenium coordination and organometallic complexes as nonlinear optical (NLO) compounds/materials, including both quadratic (second-order) and cubic (third-order) effects, as well as dipolar and octupolar chromophores. Such complexes can display very large molecular NLO responses, as characterised by hyperpolarizabilities, and bulk effects such as second harmonic generation have also been observed in some instances. The great diversity of ruthenium chemistry provides an unparalleled variety of chromophoric structures, and facile Ru" —> Ru" redox processes can allow reversible and very effective switching of both quadratic and cubic NLO effects... 

Several metalloporphyrins and phthalocyanines and numerous coordination and organometallic complexes of Rh, Ir, and Pd have also been immobilized directly onto micro- and mesoporous carbon materials, as well as onto CNTs. 

Keywords Coordination and organometallic complexes, Second-order nonlinear optics... 

Coordination and Organometallic Complexes for Second-Order Nonlinear Optics... 

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