Design, Structural Characterization and Catalytic Activity of Incomplete Dicubane Clusters of N-Substituted Diethanolamines

作者：Sama Farasha; Ansari Istikhar A; Raizada Mukul; Ahmad Musheer; Ashafaq Mo; Shahid M; Das Babulal; Shankar Krapa; Siddiqi Zafar A^*

来源：Journal of Cluster Science, 2017, 28(3): 1355-1377.

DOI：10.1007/s10876-016-1145-1

• Incomplete dicubane
• Crystal structure
• Non-covalent interactions
• Catalysis

A series of four new clusters with cationic unit [Co-4(mu(3)-OH)(Rdea) 2(L-L) 4](4+)[R = -CH3 (1 and 2) or -CH2CH2CH2CH3 (3 and 4), L-L = 1,10-phenanthroline or 2,2'-bipyridine] is designed and characterized by elemental, spectroscopic (FTIR, ESI MS, UV-visible), thermal, electrochemical, magnetic, SEM, EDX, PXRD and single crystal X-ray crystallographic techniques. Spectral and single crystal X-ray studies reveal the complexes 1-4 are tetranuclear clusters where the primary aminoalcohol derivative ligand is present in dianionic form i.e., Medea(2-) or (n)Budea(2-). It is confirmed from the magnetic and bond valence summation data that the four cobalt ions are present in mixed valent states (Co-2(2+)-Co-2(3+)), which is further corroborated from the Co-O and Co-N bond lengths in X-ray structure. The bridging two hydroxide ions consolidate the tetranuclear clusters by bonding with three neighboring metal ions and a rare incomplete dicubane core is formed in all the complexes. A supramolecular framework is generated by H-bonding, pi-pi, CH center dot center dot center dot pi, and H center dot center dot center dot H interactions. Presence of N-alkyl group and N-heterocyclic chelator facilitates the generation of these non covalent interactions thus stabilizing the framework. Of all the complexes reported here, 1 is found most efficient catalyst for the cobalt-catalyzed aerobic oxidation of neat ethylbenzene and p-xylene.

• 出版日期2017-5