HIRSHFELD SURFACE ANALYSIS OF CRYSTALS OF COMPLEXES - PRODUCTS OF REACTION IN SYSTEMS МХ2 – 1,10-PHENANTHROLINE – GeO2 – CITRIC ACID (М = Ni, Co; X = Cl, CH3COO)

Abstract

Intermolecular interactions in the coordination compounds of cation-anionic type [Ni(phen)3][Ge(HCit)2]·2H2O (I), [Co(phen)3][Ge(HCit)2]⋅2H2O (II), [Co(H2O)2(phen)2]2[Ge(Cit)2]·4H2O (III) were characterized using Hirshfeld surface analysis. It was established that the biggest contribution in the Hirshfeld surface of anions have been made by the bonds H … В / О …Н (57,8 % (I), 59,6 % (II), 63,9 % (III)), H … H (28,2 % (I), 24,9 % (II), 31,4 % (III)). At the same time interactions C … H / Н … С are less significant (9,6 %, 11,2 % and 3,2 % for I, II, III, respectively). The calculated percentage contribution of different intermolecular interactions of cations in the crystals showed, that, unlike the anions, contacts H … Н (37,9 % (IА), 38,6 % (IB), 36,2 % (IIА и IIB), 38,8 % (III)) play dominating role, while contribution of H … В / О … Н is less (26,5 % (IA and IB), 28,3 % (IIA), 24,5 % (IIB), 26 2 % (III)). Furthermore, interactions C … H / Н … С are more significant than in anions (24,8 % (IА), 27,2 % (IB), 25,6 % (IIА), 26,2 % (IIB), 21,3 % (III). It is typical for cations to have С …С bonds (5,5 % in average) that give contribution less then 1 %. It was determined that voids volume in the crystals of compounds I–III is 751,74 (I), 778,21 (II) and 423,23 (III) Å3 and surface area is 1772,28 (I), 1821,36 (II) and 628,38 (III) Å2. The total volume of the voids (15 % in I, 15,7 %, in II, 22,4 % in III) testifies the lack of big cavities in the frames of the studied compounds. Thereby analysis of intermolecular interactions with the help of Hirshfeld surface analysis showed the dominating role of hydrogen bonds H … O / O …H and contacts H … H, and minor contribution of C … H / H … C and С … С bonds for all studied compounds. The absence of p-p stacking interactions between aromatic rings of 1,10-phenanthroline in the cations of complexes I–III was also pointed out.