Crystal structures of selected beta-diketonato complexes containing unusually close NO2···NO2 contacts

Autor: Kolarić, Karolina, Gregorović, Ingrid, Borovina, Mladen, Đaković, Marijana
Přispěvatelé: Popović, Stanko, Meden, Anton
Jazyk: angličtina
Rok vydání: 2016
Předmět:
Popis: It has been shown that NO2···NO2 interactions are comparable in strength to weak hydrogen bonds and can have a structure determining role in assembling organic molecules that lack stronger halogen or hydrogen bond donors and acceptors. Nitro groups are often found in nitrogen rich energetic materials where they generally contribute to destabilization of the material resulting in its thermal, shock or mechanical instability. While it is highly unlikely that NO2···NO2 interactions will ever be used as a crystal engineering tool for the design of energetic materials, better understanding of these interactions could further unveil the correlation between structure and properties of energetic materials. We have prepared a series of hexafluoroacetylacetate complexes with 3- nitropyridine, e.g. the complexes of cobalt(II), nickel(II) and copper(II), to investigate the structure directing potential of NO2···NO2 interactions in assemblies of metal-organic systems in the absence of stronger hydrogen bonding acceptors and acceptors. Crystal structures of cobalt(II) and copper(II) complexes were determined by X-ray diffraction on single crystalline samples, and were found to be isostructural in the P4/n space group. According to the powder diffraction pattern the nickel(II) complex is also isostructural with the other two complexes form the series. Crystal structures are determined by weak C-H···O hydrogen bonds and NO2···NO2 close contacts with d(O···O)= 3.014(6), d(N···O)= 3.153(6) for the Co(II) complex and d(O···O)= 3.024(6), d(N···O)= 3.196(7) for the Cu(II) complex.
Databáze: OpenAIRE