Three-dimensional framework structures: isomorphous bis(2,6-diamino-3,5-dibromopyridinium) tetrabromidometallate(II) salts with Cd<sup>II</sup>and Mn<sup>II</sup>

Al-Far, Rawhi; Haddad, Salim F.; Ali, Basem F.

doi:10.1107/s0108270109028571

Cited by 3 publications

(1 citation statement)

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“…Our results agree well with experimental results of a recent study carried out by Al-Far et al 17 If we consider the hydrogen bonding and compare the angles of N-H.…O in the previous study (174-177º) with the angles of N-H….X for the compound (2,6-DBP)X in our study (179.9º), we find very good resemblance proving the presence of hydrogen bonding and hence its importance on the crystal structure.…”

Section: Resultssupporting

confidence: 93%

Theoretical Study of the Structure of 2,6-Dibromopyridinium Halide Salts

AlShamaileh¹

2013

Asian J. Chem.

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Theoretically, the role played by the halogen…halide interactions (C-Br…X -) and hydrogen bonding interaction (N-H…X -) in the crystal structure of 2,6-dibromopyridinium halide (2,6-DBP)X (X = Cl -, Br -) has been studied. The computational results are compared with previous experimental results for analogous compounds. There is a clear presence of (C-Br…X -) interactions and (N-H..X -) interactions in (2,6-DBP)X with almost linear (C-Br…X -) interactions angles (178.55 o ) and (N-H…X -) interactions angles (ca. 179.92 o ) and the results are then compared to experimental results for analogous compounds. This study shows that the (C-Br…X -) interactions have comparable strength with the corresponding strong NH…Xhydrogen bonds in (2,6-DBP)X. This is different from a previous result in which the (C-Br…X -) interactions are stronger than hydrogen bonding interactions in (2,5-DBP)X (X=Cl, Br and I ). The study has proven the existence of N(π)…..X -(X = Cl, Br and I) interaction. The existence of nitrogen (π) … halide ion interaction [N(π)….X -] is investigated. Calculations has been performed for the following compounds: (2,6DBP)Br, (2,6-DBP)Cl, (2,5-DBP)Br and (2,5-DBP)Cl. Calculations of energy changes that occur when the halide ion site changes above the nitrogen atom in the pyridinium bromide salt have been conducted. The position of the bromine anion was varied in three dimension forming an imaginary cubic shape above a nitrogen atom. The studied ranges of the coordinates are as follows: x= -2 to 2 Å, y = -2 to 2 Å and z = 1.5-4.5 Å. In the pyridinium bromide salt, the minimum energy for the N(π)…Brinteraction is located at a distance of 3.5-3.7 Å from the nitrogen atom to the halide anion and at an angle of ca. 25 o between the N…Brline and the normal to the plane of the pyridinium cation. These values are in good agreement to previously studied systems of similar nature.

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Section: Resultssupporting

confidence: 93%