Revealing new non-covalent interactions in polymorphs and hydrates of Acyclovir: Hirshfeld surface analysis, NCI plots and energetic calculations

Piña, Juan J.; Gil, Diego M.; Pérez, Hiram

doi:10.1016/j.comptc.2020.113133

Cited by 9 publications

(5 citation statements)

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“…A result that was somehow surprising was the poor correlation found between

italicsign ((), λ_{2}) ρ_{RDG}

and

E_{int}

. In the literature, this descriptor has been broadly used to evaluate the attractive (negative values) or repulsive (positive values) nature of intermolecular interactions, including

π - π

interactions [31, 33, 55–64]. However, we found that for the latter interactions the

italicsign ((), λ_{2}) ρ_{RDG}

values are more positive for the dimers with larger

E_{int}

, which is opposite to what occurs in hydrogen bonds [54].…”

Section: Discussionmentioning

confidence: 72%

See 1 more Smart Citation

Electron density and its reduced density gradient in the study of π–π interactions

Morales‐Pumarino

Barquera‐Lozada

2022

Int J of Quantum Chemistry

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π−π interactions are unique dispersive interactions that are important for biological systems and materials, but the study of this interaction is not trivial. It is well‐known that density functional theory (DFT) does not describe these interactions correctly and only with empirical dispersion corrections, it produces accurate energies. Moreover, little is known about the error in the electron density (ρ()r). Non‐Covalent Interaction method (NCI) has been used to analyze π stacking from the electron density. However, for these interactions, the information that can be extracted with this method is quite limited. We compare the DFT and CCSD intermolecular ρ()r. The correlation between both densities is close to one, but DFT underestimates its value. To evaluate, if the strength of the π−π interaction can be qualitatively inferred from density related scalar fields, we study the correlation between these fields (ρ()r multiplied by the sign of the second eigenvalue of its hessian, italicsign()λ2ρ, the laplacian of ρ()r, ∇2ρ()r, the virial field, V()r, the Lagrangian, G()r, and the Hamiltonian, K()r, kinetic energy density) and the interaction energy. Surprisingly, all the scalar fields have a better correlation with the energy than italicsign()λ2ρ. This quantity is normally plotted over the reduced density gradient (RDG) isosurface in the NCI method to get an insight of intermolecular interactions, but the other scalar fields give a better picture of the energetic nature of π−π interactions. Moreover, we show that italicsign()λ2ρ cannot be used as an indicator of repulsive interactions (positive values), because for the studied π systems, the more energetic the interaction is, the more positive italicsign()λ2ρ.

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“…A result that was somehow surprising was the poor correlation found between

italicsign ((), λ_{2}) ρ_{RDG}

and

E_{int}

. In the literature, this descriptor has been broadly used to evaluate the attractive (negative values) or repulsive (positive values) nature of intermolecular interactions, including

π - π

interactions [31, 33, 55–64]. However, we found that for the latter interactions the

italicsign ((), λ_{2}) ρ_{RDG}

values are more positive for the dimers with larger

E_{int}

, which is opposite to what occurs in hydrogen bonds [54].…”

Section: Discussionmentioning

confidence: 72%

“…The meaning of a positive

λ_{2}

is that the region is in the vicinity of a ring or cage critical point. However, several recent manuscripts still associate positive

italicsign ((), λ_{2}) ρ

values with repulsive interactions [55–64]. Even more surprising is that the stronger the interaction, the more positive the

italicsign ((), λ_{2}) ρ_{RDG}

value.…”

Section: Resultsmentioning

confidence: 99%

Electron density and its reduced density gradient in the study of π–π interactions

Morales‐Pumarino

Barquera‐Lozada

2022

Int J of Quantum Chemistry

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show abstract

“…The fingerprint plots (2D scans of 3D surfaces) are a convenient way to analyze the intermolecular interactions present in crystals. This method can be used to analyze the π–stacking interactions [ 40 ], the halogen and hydrogen bonds [ 41 , 42 ], anion–π [ 28 ] and other weak non-covalent interactions [ 43 , 44 ].…”

Section: Resultsmentioning

confidence: 99%

Novel Synthesis Methods of New Imidazole-Containing Coordination Compounds Tc(IV, V, VII)—Reaction Mechanism, Xrd and Hirshfeld Surface Analysis

Volkov

Novikov

Grigoriev

et al. 2022

IJMS

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In this work, we have proposed two new methods for the synthesis of [TcO2L4]+ (where L = imidazole (Im), methylimidazole (MeIm)) complexes using thiourea (Tu) and Sn(II) as the reducing agents. The main and by-products of the reactions were determined, and possible reaction mechanisms were proposed. We have shown that the reduction of Tc(VII) with thiourea is accompanied by the formation of the Tc(III) intermediate and further oxidation to Tc(V). The reaction conditions’ changing can lead to the formation of Tc(VII) and Tc(IV) salts. Seven new crystal structures are described in this work: Tc(V) complexes, salts with Tc(VII) and Tc(IV) anions. For the halide salts of Tu the cell parameters were determined. In all of the obtained compounds, except for [TcO2(MeIm)4]TcO4, there are π–stacking interactions between the aromatic rings. An increase in the anion size lead to weakening of the intermolecular interactions. The halogen bonds and anion-π interactions were also found in the hexahalide-containing compounds. The Hirshfeld surface analysis showed that the main contribution to the crystal packing is created by the van der Waals interactions of the H···H type (42.5–55.1%), H···C/C ···H (17.7–21.3%) and hydrogen bonds, which contribute 15.7–25.3% in total.

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“…[40] Fingerprint plots or 2D d norm surface unfolding is a convenient way to summarize the intermolecular contacts present in crystals by decomposing this fingerprint plot into functions to identify specific interactions. This method can be used to analyze π-interactions (such as anion-π, anion-π-cation, anion-π-π and π-stacking), [6,42] halogen and hydrogen bonds, [43,44] and other weak non-covalent interactions. [45,46] The donor-acceptor groups are visualized using a standard (high) surface resolution and d norm surfaces, as illustrated in Figure 5.…”

Section: Chemistryselectmentioning

confidence: 99%

Cation Protonation Degree Influence on the Formation of Anion⋅⋅⋅Anion and Other Non‐Valent Interactions in Guaninium Perrhenates and Pertechnetate

et al. 2022

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H 2 Gua(ReO 4 ) 2 , HGuaReO 4 and HGuaTcO 4 were first obtained and structurally characterized. Two types of anionic interactions were found in the structure with the twice protonated cation. One type of the rare double-lock interaction of perrhenate anions was found in the case of the singly protonated guanine salt. Singly charged cations are linked by hydrogen bonds into layer. π-Stacking interactions between these layers form 3dimensional frame. Multiple and relatively abundant anion-π interactions are formed in H 2 Gua(ReO 4 ) 2 as compared to HGuaReO 4 and HGuaTcO 4 . Different types of crystal packing are formed in the compounds under research. Hirshfeld surface analysis has given evidence that the main contribution to intermolecular interactions for the cations is made by hydrogen bonds of the O⋅⋅⋅H/H⋅⋅⋅O type in all structures, O⋅⋅⋅C/C⋅⋅⋅O and O⋅⋅⋅N/N⋅⋅⋅O interactions in H 2 Gua(ReO 4 ) 2 , N⋅⋅⋅H/H⋅⋅⋅N and H⋅⋅⋅H interactions in HGuaReO 4 and HGuaTcO 4 .

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Revealing new non-covalent interactions in polymorphs and hydrates of Acyclovir: Hirshfeld surface analysis, NCI plots and energetic calculations

Cited by 9 publications

References 50 publications

Electron density and its reduced density gradient in the study of π–π interactions

Electron density and its reduced density gradient in the study of π–π interactions

Novel Synthesis Methods of New Imidazole-Containing Coordination Compounds Tc(IV, V, VII)—Reaction Mechanism, Xrd and Hirshfeld Surface Analysis

Cation Protonation Degree Influence on the Formation of Anion⋅⋅⋅Anion and Other Non‐Valent Interactions in Guaninium Perrhenates and Pertechnetate

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