Substitution Reaction And Vapochromic Of Osmafurans And Organonitrile

Aromatic metallacycles are a kind of d-p? conjugated systems in which a C-H group of conventional aromatic compounds is substituted by a transition metal and its ancillaries.Aromatic metallacycle have recently received increasing attention because of their potential properties in light,electricity,magnetism or catalysis.At present,the sthudy in this is mainly focused on the synthesis and the reactivity studies.However,there are few studies on the supermolecular self-assembly using aromatic metallacycles as the building blocks.The research on its properties is still in its infancy.In our previous work,we have synthesized a series of di-organonitrile coordinated osmafurans compounds through the substitution reactions osmafuran and organonitrile ligands,such as acetonitrile,phenylacetonitrile and p-benzenediacetonitrile.However,their proerties has not been further studied.In this paper,a new osmafuran 2-3 was synthesized,which reacted with phenyl acetonitrile,p-benzenediacetonitrile and biphenyl diacetonitrile to produce the four organonitrile-coordinated osmafurans 2-4,2-5,2-6,2-7,and characterized by NMR,X-ray single crystal diffraction and high resolution mass spectrometry.In our previous results,a flexible bidentate ligand usually gives a dinuclear cycle compound with a chair structure(compounds 3-1 and 3-2).Interestingly,we found that when these compounds exposed to volatile organic solvents,a change of color from yellow to orange-red was observed.The color could change back to yellow by grinding,shg a stable phenomenon of vapochromic.That could be explained by the intermolecular forces.Moreover,these forces still exist after the removal of organic vapor molecules.Only giving a certain amount of mechanical grinding to destroy this force,the solid color can be back to the original yellow.The highly stable vapochromic behavior of these osmium macrocycle compounds with a specially constructed chair conformation is rare.These compouds are potentially used in chemical sensors,environmental monitors,etc.