Self‐assembled Complexes of the Ligand Methyl(2‐pyrazinyl)ketone Oxime with Oxime and Anion···Oxime Interactions

Abstract

AbstractIn this work, the ligand methyl(2‐pyrazinyl)ketone oxime with a pyrazinyl ring and an oxime moiety was synthesized. The two complexes [Cu3(μ3‐OH)(μ‐OPz)3(NO3)2]·2H2O·CH3OH (1) and [Ag3(HOPz)2(NO3)2](NO3) (2) [HOPz = methyl(2‐pyrazinyl)ketone oxime] could be isolated and structurally characterized. Complex 1 exhibits a fundamental structural unit of trinuclear Cu3(μ3‐OH) clusters, whereas complex 2 has a three‐core linear‐shaped silver(I) structure. For complexes 1 and 2, the pyrazinyl ring of the HOPz ligand acts as an electron‐deficient heterocycle and the nitrate anion is the electron‐rich unit. The structure of complex 1 is arranged by O(W)···O(MeOH)···O(NO3–) hydrogen bonds into a 1D chain, which is furthermore assembled into a 2D structure by C–H···πi (CPz) interactions between pyridyl rings and methyl groups. Complex 2 has a three‐core linear‐shaped structure, the nitrate oxygen atoms are involved in weak Ag···O interactions, which are linked into 1D chains by oxime···O(NO3–) hydrogen bonded R22(12) dimers. The O(NO3–)···πii (CPz) interactions further connect the adjacent moieties into a 3D supramolecular network. Complexes 1 and 2 present intriguing self‐complementary supra‐molecular architectures through combination of coordination, hydrogen bonding, C–H···π as well as O(NO3–)···π weak interactions. The results also provide a prototype for the development of frameworks with anions and multiple guest‐binding sites using general principles of crystal design.