Hello Sengottuvelan,

Schiff bases, R'RC=NR'', in fact form such a wide variety of complexes with metals in the +II oxidation state that examples can be easily found:

https://doi.org/10.1016/B0-08-043748-6/01070-7

A very well known example is the copper-Schiff base complex developed by Noyori for the metal-carbenoid cyclopropanation of styrene. This work was awarded with the Nobel Prize in Chemistry in 2001.

https://doi.org/10.1016/S0040-4020(01)91998-2

Dear Sengottuvelan Balasubramanian

Many thanks for posting such an interesting question on RG. A Schiff base is a compound with the general formula R1R2C=NR, where R is the alkyl or aryl group but is not H, R1 and R2 may be alkyl or aryl group and hydrogen H as well. Such compounds are good ligand in coordination chemistry due to the presence of a lone pair electron on the nitrogen atom which is further bonded by a polarizable pai bond. Schiff bases are notable ligands capable of coordinating versatile metal ions with variable oxidation states. Following links may help you finding M(II)-Schiff base complexes.

Article Synthesis, Characterization and Antibacterial Activity of Sc...

Article Spectral, Molecular Modeling, and Biological Activity Studie...

Article Nano-Azo Ligand and Its Superhydrophobic Complexes: Synthesi...

Article Synthesis, characterization of Schiff base metal complexes a...

Article Metal complexes of Schiff base: Preparation, characterizatio...

Article Synthesis, Characterization and Crystal Structures of Four D...

Article Metal Complexes of a Novel Schiff Base Based on Penicillin: ...

You can easily find more articles on this topic in internet. Good luck with your work.

Nice to see the responses from Florian and Shafikul. In fact the literature abounds with several thousands of such examples. The answer is very simple Then why this question was asked? It is a prelude to my next question:

Is there any report on the Schiff base ligand forming complex with metal in zero oxidation state?

Dear Sengottuvelan Balasubramanian as already discussed in the course of your closely related question about the zero oxidation state, the vast majority of all transition metals complexes contain the the central metal atoms in the +2 to +6 oxidation states, e.g. cobalt, nickel, vanadyl, uranyl etc. For a nice overview about the chemistry and applications of transition metal Schiff base complexes please have a look at the following useful review article:

A review on versatile applications of transition metal complexes incorporating Schiff bases

Article A review on versatile applications of transition metal compl...

Fortunately this review article is freely available as public full text on RG and can be downloaded as pdf file.

I hope this helps. Good luck with your work and best wishes, Frank Edelmann

Thank you for your response. The Schiff base is more than a century old and innumerable number of articles and reviews on their metal complexes are available in the literature. As I have indicated in my earlier question, this point was raised to make the young researchers understand that when there are so many examples available for metals in positive oxidation states , there is hardly any reference with metals in zero oxidation state in these complexes.