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In this study, Fe3O4 nanoparticles (FeNPs) decorated with halogenated perylene diimides (PDIs) have been used for capturing VOCs (volatile organic compounds) through noncovalent binding. Concretely, we have used tetrachlorinated/brominated PDIs as well as a nonhalogenated PDI as a reference system. On the other hand, methanol, ethanol, propanol, and butanol were used as VOCs. Experimental studies along with theoretical calculations (the BP86-D3/def2-TZVPP level of theory) pointed to two possible and likely competitive binding modes (lone pair–π through the π-acidic surface of the PDI and a halogen bond via the σ-holes at the Cl/Br atoms). More in detail, thermal desorption (TD) experiments showed an increase in the VOC retention capacity upon increasing the length of the alkyl chain, suggesting a preference for the interaction with the PDI aromatic surface. In addition, the tetrachlorinated derivative showed larger VOC retention times compared to the tetrabrominated analog. These results were complemented by several state-of-the-art computational tools, such as the electrostatic surface potential analysis, the Quantum Theory of Atoms in Molecules (QTAIM), as well as the noncovalent interaction plot (NCIplot) visual index, which were helpful to rationalize the role of each interaction in the VOC···PDI recognition phenomena. [ABSTRACT FROM AUTHOR]

As(III) S‐adenosylmethionine methyltransferases, pivotal enzymes in arsenic metabolism, facilitate the methylation of arsenic up to three times. This process predominantly yields trivalent mono‐ and dimethylarsenite, with trimethylarsine forming in smaller amounts. While this enzyme acts as a detoxifier in microbial systems by altering As(III), in humans, it paradoxically generates more toxic and potentially carcinogenic methylated arsenic species. The strong affinity of As(III) for cysteine residues, forming As(III)‐thiolate bonds, is exploited in medical treatments, notably in arsenic trioxide (Trisenox®), an FDA‐approved drug for leukemia. The effectiveness of this drug is partly due to its interaction with cysteine residues, leading to the breakdown of key oncogenic fusion proteins. In this study, we extend the understanding of As(III)′s binding mechanisms, showing that, in addition to As(III)−S covalent bonds, noncovalent O⋅⋅⋅As pnictogen bonding plays a vital role. This interaction significantly contributes to the structural stability of the As(III) complexes. Our crystallographic analysis using the PDB database of As(III) S‐adenosylmethionine methyltransferases, augmented by comprehensive theoretical studies including molecular electrostatic potential (MEP), quantum theory of atoms in molecules (QTAIM), and natural bond orbital (NBO) analysis, emphasizes the critical role of pnictogen bonding in these systems. We also undertake a detailed evaluation of the energy characteristics of these pnictogen bonds using various theoretical models. To our knowledge, this is the first time pnictogen bonds in As(III) derivatives have been reported in biological systems, marking a significant advancement in our understanding of arsenic's molecular interactions. [ABSTRACT FROM AUTHOR]

Reactions in water between the Cu2(µ-EGTA) chelate (EGTA = ethylene-bis(oxyethyleneimino)tetraacetate(4-) ion) and Hdap in molar ratios 1:1 and 1:2 yield only blue crystals of the ternary compound [Cu4(μ-EGTA)2(μ-H(N3)dap)2(H2O)2]·7H2O (1), which has been studied via single-crystal X-ray diffraction and various physical methods (thermal stability, spectral and magnetic properties), as well as DFT theoretical calculations. In the crystal, uncoordinated water is disordered. The tetranuclear complex molecule also has some irrelevant disorder in an EGTA-ethylene moiety. In the complex molecule, both bridging organic molecules act as binucleating ligands. There are two distorted five- and two six-coordinated Cu(II) centers. Each half of EGTA acts as a tripodal tetradentate Cu(II) chelator, with a mer-NO2 + O(ether, distal) conformation. Hdap exhibits the tautomer H(N3)dap, with the dissociable H-atom on its less basic N-heterocyclic atom. These features favor the efficient cooperation between Cu-N7 or Cu-N9 bonds with appropriate O-EGTA atoms, as N6-H···O or N3-H···O interligand interactions, respectively. The bridging role of both organics determines the tetranuclear dimensionality of the complex. In this crystal, such molecules associate in zig-zag chains built by alternating π–π interactions between the five- or six-atom rings of Hdap ligands of adjacent molecules. DFT theoretical calculations (using two different theoretical models and characterized by the quantum theory of "atoms in molecules") reveal the importance of these π–π interactions between Hdap ligands, as well as those corresponding to the referred hydrogen bonds in the contributed tetranuclear molecule. [ABSTRACT FROM AUTHOR]

Considering that Cu(tda) chelate (tda: dithioacetate) is a receptor for adenine and related 6-aminopurines, this study reports on the synthesis, molecular and crystal structures, thermal stability, spectral properties and DFT calculations related to [Cu(tda)(9heade)(H2O)]·2H2O (1) [9heade: N9-(2-hydroxyethyl)adenine]. Concerning the molecular recognition of (metal chelate)-(adenine synthetic nucleoside), 1 represents an unprecedented metal binding pattern (MBP) for 9heade. However, unprecedentedly, the Cu(tda)-9heade molecular recognition in 1 is essentially featured in the Cu-N1(9heade) bond, without any N6-H⋯O(carboxyl tda) interligand interaction. Nevertheless, N1 being the most basic donor for N9-substituted adenines, this Cu-N1 bond is now assisted by an O2–water-mediated interaction (N6-H⋯O2 and O2⋯Cu weak contact). Also, in the crystal packing, the O-H(ol) of 9heade interacts with its own adenine moiety as a result of an O3–water-mediated interaction (O(ol)-H⋯O3 plus O3-H36⋯π(adenine moiety)). Both water-mediated interactions seem to be responsible for serious alterations in the physical properties of crystalline or grounded samples. Density functional theory calculations were used to evaluate the interactions energetically. Moreover, the quantum theory of atoms-in-molecules (QTAIM), in combination with the noncovalent interaction plot (NCIPlot), was used to analyze the interactions and rationalize the existence and relative importance of hydrogen bonding, chalcogen bonding and π-stacking interactions. The novelty of this work resides in the discovery of a novel binding mode for N9-(2-hydroxyethyl)adenine. Moreover, the investigation of the important role of water in the solid state of 1 is also relevant, along with the chalcogen bonding interactions demonstrated by the density functional theory (DFT) study. [ABSTRACT FROM AUTHOR]

Two multi-component coordination compounds of Mn(II), viz. [Mn(H2O)6](2-Mepy)2(4-NO2bz)2·2H2O (1) and [Mn(H2O)6][Mn(2,3-PDCH)3]2 (2) (where, 2-Mepy = 2-methylpyridine, 4-NO2bz = 4-nitrobenzoate, 2,3-PDC = 2,3-pyridinedicarboxylate), have been synthesized and characterized using elemental, spectroscopic (FT-IR and electronic), TGA and single-crystal X-ray diffraction analyses. Complex 1 is a co-crystal hydrate of Mn(II) involving uncoordinated 2-Mepy, 4-NO2bz and water molecules; while compound 2 is a multi-component molecular complex salt of Mn(II) comprising cationic [Mn(H2O)6]2+ and anionic [Mn(2,3-PDCH)3]−complex moieties. The uncoordinated 2-Mepy and 4-NO2bz moieties of 1 are involved in lone-pair (l.p)-π and C–H⋯π interactions which stabilize the layered assembly of the compound. The crystal structure of compound 2 has been previously reported. However, we have explored the unusual enclathration of complex cationic moieties within the supramolecular host cavities formed by the molecular assembly of complex anionic moieties. The supramolecular assemblies obtained in the crystal structure have been further studied theoretically using DFT calculations, quantum theory of atoms-in-molecules (QTAIM) and non-covalent interaction plot (NCI plot) computational tools. Theoretical studies reveal that the combination of π-staking interactions (l.p-π, π-π and C–H···π) have more structure-guiding roles compared to the H-bonds. The large binding energy of π-stacking interactions in 2 is due to the antiparallel orientation of aromatic rings and their coordination to the metal centers, thereby increasing the contribution of the dipole–dipole interactions. [ABSTRACT FROM AUTHOR]

In this manuscript, we have examined the CSD (Cambridge Structural Database) to investigate the relative ability of Te and I (in practice, the heaviest chalcogen and halogen atoms) in di- and tri-iododiorganyltellurium(IV) derivatives to establish σ-hole interactions. The geometry around the Te(IV) in this type of compound is trigonal bipyramidal where the stereoactive lone pair at Te(IV) occupies one of the equatorial positions. In the solid state, Te(IV) tends to form pseudo-octahedral coordination by establishing strong noncovalent interactions opposite to the two covalent bonds of the equatorial plane. Such contacts can also be classified as chalcogen bonds following the recommendation of the International Union of Pure and Applied Chemistry (IUPAC). Such contacts have been analyzed energetically in this work using density functional theory (DFT) calculations, rationalized using molecular electrostatic potential (MEP) surface analysis and characterized using a combination of the quantum theory of atoms in molecules (QTAIM) and noncovalent interaction plot (NCIplot) computational tools. Finally, the observation of halogen bonds and type I halogen···halogen contacts is also emphasized and compared to the chalcogen bonds. Energy decomposition analysis has also been performed to compare the physical nature of chalcogen, halogen and type I interactions. [ABSTRACT FROM AUTHOR]

Co‐crystallization of 180°‐orienting σ‐hole‐accepting tectons, namely, 1,4‐diisocyanobenzene (1) and 1,4‐diisocyanotetramethylbenzene (2), with such homoditopic halogen bond donors as 1,4‐diiodotetrafluorobenzene (1,4‐FIB) and 4,4'‐diiodoperfluorobiphenyl (4,4'‐FIBP) afforded co‐crystals 1 ⋅ 1,4‐FIB, 1 ⋅ 4,4'‐FIBP, and 2 ⋅ 1,4‐FIB. Their solid‐state structures exhibit 1D‐supramolecular arrangements, which are based on poorly explored I⋅⋅⋅C halogen bonding; this study is the first in which the supramolecular assembly utilizing halogen bonding with a terminal C atom was performed. The use of the potentially tetrafunctional σ‐hole accepting tetraiodoethylene (TIE) leads to supramolecular architecture of a higher dimension, 3D‐framework, observed in the structure of 1 ⋅ TIE. DFT calculations, used to characterize the halogen bonding situation, revealed that the I⋅⋅⋅C non‐covalent interactions are moderately strong, ranging from −4.07 in 1 ⋅ TIE to −5.45 kcal/mol in 2 ⋅ 1,4‐FIB. The NBO analysis disclosed that LP(C)→σ* charge transfer effects are relevant in all co‐crystals. [ABSTRACT FROM AUTHOR]

Two coordination compounds of Cu(II), namely, [Cu (phen)2Cl](NO3)·H2O (compound 1) and [Cu2(µ-Cl2)Cl2(Hdmpz)4] (compound 2), where phen = 1,10-phenanthroline and Hdmpz = 3,5-dimethylpyrazole, were synthesized at room temperature and characterized using elemental analysis, TGA, spectroscopic techniques (FT-IR and electronic) and single-crystal X-ray diffraction studies. The cooperative anion–π/π–π/anion–π assemblies involving the coordinated phen, along with the uncoordinated nitrate moieties, played pivotal roles in the stabilization of the crystal structure of compound 1. Unconventional type I Cl⋯Cl interactions involving the coordinated Cl atoms provided reinforcement to the crystal structure of compound 2. We theoretically explored the supramolecular assemblies observed in the crystal structures of compounds 1 and 2 using DFT calculations, MEP surface analysis and combined NCI plot/QTAIM computational tools. Theoretical analysis revealed that the antiparallel π-stacking interactions in compound 1 and the N–H···Cl H-bonds in compound 2 were the strong structure-guiding non-covalent synthons which stabilized the compounds. In the anion–π/π–π/anion–π assembly observed in compound 1, the anion–π interaction reinforced the π-stacking by reducing the electrostatic repulsion between the metal-coordinated electron-deficient phen rings. [ABSTRACT FROM AUTHOR]

Two new Ni(II) and Co(II) coordination compounds, viz., [Ni(H2O)5(DMAP)](IPhth)·2H2O (1) and [Co(Hdmpz)4(H2O)2]Cl2 (2) (where DMAP = 4-dimethylaminopyridine, IPhth = Isophthalate, Hdmpz = 3,5-dimethylpyrazole),were synthesized and characterized using elemental analysis, TGA, spectroscopic (FTIR and electronic) and single-crystal X-ray diffraction techniques. Compound 1 crystallizes as a co-crystal hydrate of Ni(II), whereas compound 2 is a mononuclear compound of Co(II). The crystal structure analysis of compound 1 reveals the presence of various non-covalent interactions such as anion–π, π–π, C–H∙∙∙π, C–H∙∙∙C, etc., which stabilize the layered assembly of the compound. In compound 2, enclathration of counter chloride ions within the supramolecular trimeric host cavity plays a crucial role in the stabilization of the compound. The non-covalent interactions observed in the crystal structures were further studied theoretically, focusing on the cooperative π-stacking interactions between the DMAP and IPhth counter-ions in 1. To identify the non-covalent interactions of the compounds, Hirshfeld surfaces and their associated two-dimensional fingerprint regions were analyzed. Theoretical calculations confirm that H-bonding interactions combined with the π-stacking contacts are crucial synthons for the solid-state stability of compound 1. [ABSTRACT FROM AUTHOR]

Noncovalent interactions involving metals as electron acceptors are continuously under investigation. The term "matere bond" has been proposed to identify noncovalent donor–acceptor interactions where elements of group 7 of the periodic table play the role of the electrophilic site. Most of the works on matere bonds involve rhenium atoms usually in +7 oxidation state. This work emphasizes for the first time their importance in technetium derivatives in several oxidation states (+7, +6, +5, and +3). The Cambridge Structural Database (CSD) in combination with density functional theory (DFT) calculations are used to demonstrate the structure directing role of matere bonds in X-ray structures, even involving anion⋯anion interactions. Further characterization of the matere bonds is provided using Molecular Electrostatic Potential (MEP) surface calculations, the "Quantum Theory of Atoms in Molecules" (QTAIM), and Natural Bond Orbital (NBO) analyses. It should be emphasized that some types of matere bonds reported herein have not been previously described in literature. [ABSTRACT FROM AUTHOR]

Herein, the synthesis and X‐ray structures of three α,β "two wall" aryl‐extended calix[4]pyrroles having either identical (symmetrically substituted) or different (non‐symmetrically substituted) meso‐aryl substituents (aryl=4‐ethynylphenyl and 4‐iodophenyl) are reported. The X‐ray structure of the co‐crystal formed by the two symmetrically substituted calix[4]pyrroles is also described. In the solid state, all studied α,β‐calix[4]pyrroles exhibit a 1,3‐alternate conformation with two co‐crystallized acetonitrile solvent molecules H‐bonded to adjacent cis‐pyrrole rings. Remarkably, the 1,3‐conformer of the non‐symmetrically substituted iodophenyl/ethynylphenyl compound is intrinsically chiral. The two enantiomers are present in the average asymmetric unit in a 65 : 35 occupancy ratio displaying a head‐to‐tail directional disorder. This is due to the functional complementarity and the isosteric and isoelectronic properties of the para‐substituents: iodo and ethynyl. That is, the negative belt of iodine is similar to the negative π‐system of the C≡C triple bond and the σ‐hole in the iodine atom is similar to the positive proton at the C≡C−H group. [ABSTRACT FROM AUTHOR]

It has been proposed that late transition metals with low coordination numbers (square planar or linear) can act as nucleophiles and participate in σ-hole interactions as electron donors. This is due to the existence, in this type of metal complexes, of a pair of electrons located at high energy d-orbitals (dz2 or dx2-y2), which are adequate for interacting with antibonding σ-orbitals [σ*(X–Y)] where Y is usually an electron withdrawing element and X an element of the p-block. This type of d[M]→σ*(X–Y) interaction has been reported for metals of groups 9–11 in oxidation states +1 and +2 (d8 and d10) as electron donors and σ-holes located in halogen and chalcogen atoms as electron acceptors. To our knowledge, it has not been described for σ-holes located in pnictogen atoms. In this manuscript, evidence for the existence of pnictogen bonding involving the square planar Pt(II) metal as the electron donor and Sb as the electron acceptor is provided by using an X-ray structure retrieved from the Cambridge Structural Database (CSD) and theoretical calculations. In particular, the quantum theory of atoms in molecules (QTAIM), the noncovalent interaction plot (NCIPlot) and molecular electrostatic potential (MEP) methods were used. Moreover, to further confirm the nature of the Sb···Pt(II) contact, a recently developed method was used where the electron density (ED) and electrostatic potential (ESP) distribution were compared along the Sb···Pt(II) bond path. [ABSTRACT FROM AUTHOR]

The chalcogen bond has been recently defined by the IUPAC as the attractive noncovalent interaction between any element of group 16 acting as an electrophile and any atom (or group of atoms) acting as a nucleophile. Commonly used chalcogen bond donor molecules are divalent selenium and tellurium derivatives that exhibit two σ-holes. In fact, the presence of two σ-hole confers to the chalcogen bonding additional possibilities with respect to the halogen bond, the most abundant σ-hole interaction. In this manuscript, we demonstrate that selenoxides are good candidates to be used as σ-hole donor molecules. Such molecules have not been analyzed before as chalcogen bond donors, as far as our knowledge extends. The σ-hole opposite to the Se=O bond is adequate for establishing strong and directional ChBs, as demonstrated herein using the Cambridge structural database (CSD) and density functional theory (DFT) calculations. Moreover, the effect of the metal coordination of the selenoxide to transition metals on the strength of the ChB interaction has been analyzed theoretically. The existence of the ChBs has been further supported by the quantum theory of atoms in molecules (QTAIM) and the noncovalent interaction plot (NCIPlot). [ABSTRACT FROM AUTHOR]

The co‐crystallization of tetracyanobenzene (TCB) with haloarenes ArX provided six new co‐crystals TCB ⋅ ArX (ArX=PhCl, PhBr, 4‐MeC6H4Cl, 4‐MeC6H4Br, 4‐MeOC6H4Cl, 1,2‐Br2C6H4) which were studied by X‐ray diffraction. In these systems, the strong collective effect of π⋅⋅⋅π stacking interactions and lone pair‐(X)⋅⋅⋅π‐hole‐(C) bondings between TCB and ArX promote the strength of X⋅⋅⋅Ncyano halogen bonding (HaB). Theoretical studies showed that the stacking interactions affect the σ‐hole depth of the haloarenes, thus significantly boosting their ability to function as HaB donors. According to the molecular electrostatic potential calculations, the σ‐ hole‐(Cl) value (1.5 kcal/mol) in the haloarene 4‐MeOC6H4Cl (featuring an electron‐rich arene moiety and exhibiting very poor σ‐hole‐(Cl) ability) increases significantly in the stacked trimer (TCB)2 ⋅ 4‐MeOC6H4Cl (12.5 kcal/mol). Theoretical DFT calculations demonstrate the dramatic increase of X⋅⋅⋅Ncyano HaB strength for stacked trimers in comparison with parent unstacked haloarenes. [ABSTRACT FROM AUTHOR]

The term matere bond has been recently used to refer to an attractive noncovalent interaction between any element of group 7 acting as an electrophile and any atom (or group of atoms) acting as a nucleophile. The utilization of metals such as σ-hole donors is starting to attract the attention of the scientific community. In this manuscript, a comparison between matere bonds and well-known σ-hole interactions (halogen and chalcogen bonds) is carried out using three X-ray structures, retrieved from the Cambridge structural database (CSD), and density functional theory calculations (DFT). The novelty of this work resides in the utilization of a neutral Re(VII) system as the matere bond donor and multivalent chalcogen and halogen donors. In fact, as far as our knowledge extends, the description of σ-hole interactions in Se(VI) is unprecedented in the literature. The σ-hole interactions in Re(VII), Se(VI) and Cl(VII) electron acceptors are analyzed and compared using several computational tools. [ABSTRACT FROM AUTHOR]

Four co-crystals involving dicarboxylic acids and pyridine derivatives, viz. (ox)0.5(2-CNpy) (1), (adp)(4-CNpy)2 (2), (tp)(4-CNpy)2 (3) and (adp)(3-CNpy)2 (4) (ox = oxalic acid, tp = terephthalic acid, adp = adipic acid, CNpy = cyanopyridine), have been synthesized at room temperature in water medium. Crystal-structure analysis of co-crystal 1 reveals the presence of unconventional O···π(oxalic acid)-hole interaction with the C-C bond of ox moiety, along with parallel nitrile–nitrile interactions. The structural topologies of co-crystals 2–4 unfold the presence of antiparallel nitrile–nitrile interactions involving the CNpy moieties. The molecular associations involving the H-bonds and other unconventional contacts among the co-formers of the multicomponent co-crystals are analyzed using density functional theory (DFT) calculations combined with molecular electrostatic potential (MEP) surface, quantum theory of atoms-in-molecules (QTAIM) and noncovalent interaction (NCI) plot computational tools. The computational studies revealed the presence of unconventional O···π-hole interaction in 1 and the H-bonded synthons with π-stacked nitrile contacts involving CNpy moieties in co-crystals 2–4. The energetic features of the noncovalent contacts reveal the crucial roles of the H-bonding synthons and π-stacking interactions in the multicomponent compounds. [ABSTRACT FROM AUTHOR]

The synthetic protocol and solid state characterization of two new coumarin‐pyrazolylthiazole hybrids (1‐2) are detailed in this manuscript. Synthesized compounds were characterized applying nuclear magnetic resonance, Fourier‐transform infrared spectroscopy and single‐crystal X‐ray diffraction techniques. A detailed structural analysis of 3‐(2‐(5‐(4‐bromophenyl)‐3‐(4‐fluorophenyl)‐4,5‐dihydropyrazol‐1‐yl)thiazol‐4‐yl)‐2H‐chromen‐2‐one (1) and 3‐(2‐(3,5‐bis(4‐bromophenyl)‐4,5‐dihydropyrazol‐1‐yl)thiazol‐4‐yl)‐2H‐chromen‐2‐one (2) is reported along with a detailed description of the noncovalent interactions and their evaluation using Hirshfeld surface analysis, emphasizing the structure‐directing role of C−H⋅⋅⋅O, Br⋅⋅⋅π and π–π interactions. Finally, DFT energetics, molecular electrostatic potential (MEP), quantum theory of "atoms‐in‐molecules" (QTAIM) and noncovalent interaction plot (NCIplot) index computations have been used to further investigate the relative importance of two different π‐stacking complexes observed in the solid state of both compounds, which are recurrent binding motifs in their crystal packing. [ABSTRACT FROM AUTHOR]

Osme bonds have been recently defined as the attractive interaction between an element of group 8 acting as an electrophile and any atom or group of atoms acting as a nucleophile. To date, the known examples of osme bonds in X-ray structures involve mostly the highly reactive OsO4 and amines and amine oxides. In this work, evidence supporting the existence of osme bonds in osmium(VI) derivatives is reported. In particular, nitrido-osmium(VI) complexes that present square-pyramidal geometries are well disposed to participate in osme bonds opposite to the Os≡N bond. By using a combination of experimental and theoretical results, the existence and importance of this new class of σ-hole interactions is demonstrated in the solid state of several nitrido-osmium(VI) derivatives. [ABSTRACT FROM AUTHOR]

The crystal structure of a new zonisamide cocrystal, an anticonvulsant drug used to treat the symptoms of epilepsy and Parkinson's disease, with ϵ-caprolactam is reported herein. The structure has been solved by direct space methodologies from powder X-ray diffraction data. The refinement of the structure was conducted by the Rietveld method assisted by the dispersion-corrected density-functional theory (D-DFT) calculations and periodic boundary conditions. Further analysis of the structure reveals several H-bonded synthons and self–assembled dimers that have been further analyzed by DFT calculations and other computational tools such as molecular electrostatic potential (MEP) surfaces and the quantum theory of "atom-in-molecules" (QTAIM). [ABSTRACT FROM AUTHOR]

In this work the crystal structure of the previously described orthorhombic polymorph of the coupling reagent Oxyma has been revised, corrected now as centrosymmetric and analyzed by means of DFT calculations. In the solid state the structure forms a network of H-bonds and self–assembled dimers that are held together by the formation of N···C π–hole interactions involving the C-atom of the imino group. The H-bonding and π–hole interactions observed in the solid state were rationalized using molecular electrostatic potential (MEP) surfaces, focusing on the H-bond donor-acceptor groups and the π-hole observed above and below the molecular plane. The interactions and their interplay have been characterized by using two methodologies based on the topology of the electron density, which are the quantum theory of "atom-in-molecules" (QTAIM) and the noncovalent interaction plot (NCIplot). [ABSTRACT FROM AUTHOR]

We report a series of rotaxane‐based anion–π catalysts in which the mechanical bond between a bipyridine macrocycle and an axle containing an NDI unit is intrinsic to the activity observed, including a [3]rotaxane that catalyses an otherwise disfavoured Michael addition in >60 fold selectivity over a competing decarboxylation pathway that dominates under Brønsted base conditions. The results are rationalized by detailed experimental investigations, electrochemical and computational analysis. [ABSTRACT FROM AUTHOR]

In X‐ray structures of the isomorphic mer‐[IrX3(THT)(CNXyl)2] (X=Cl 1, Br 2; THT=tetrahydrothiophene; Xyl=2,6‐Me2C6H3−) complexes, we revealed short intermolecular contacts between the C‐atom of an isocyanide methyl group and halide ligands of another molecule. Geometrical consideration of the X‐ray data and analysis of appropriate DFT studies allowed the attribution of these contacts to CMe⋅⋅⋅X−IrIII (X=Cl, Br) tetrel bond. Specifically, through the application of DFT calculations and various theoretical models, the presence of tetrel bonding interactions was validated, and the contribution of the CMe⋅⋅⋅X−IrIII interaction was assessed. The reinforcement of the tetrel bond upon the isocyanide coordination to iridium(III) is substantiated by molecular electrostatic potential (MEP) surface calculations. To distinguish the tetrel bonding characteristics of CMe⋅⋅⋅X−IrIII (X=Cl, Br) interactions from conventional hydrogen bonding, we employed multiple computational methodologies, including Natural Bond Orbital (NBO) analysis and Electron Localization Function (ELF) analysis. Additionally, Energy Decomposition Analysis (EDA) was applied to selected model systems to explore the underlying physical nature of these interactions. [ABSTRACT FROM AUTHOR]

Three novel bis-urea fluorescent low-molecular-weight gelators (LMWGs) based on the tetraethyl diphenylmethane spacer—namely, L1, L2, and L3, bearing indole, dansyl, and quinoline units as fluorogenic fragments, respectively, are able to form gel in different solvents. L2 and L3 gel in apolar solvents such as chlorobenzene and nitrobenzene. Gelator L1 is able to gel in the polar solvent mixture DMSO/H2O (H2O 15% v/v). This allowed the study of gel formation in the presence of anions as a third component. An interesting anion-dependent gel formation was observed with fluoride and benzoate inhibiting the gelation process and H2PO4−, thus causing a delay of 24 h in the gel formation. The interaction of L1 with the anions in solution was clarified by 1H-NMR titrations and the differences in the cooperativity of the two types of NH H-bond donor groups (one indole NH and two urea NHs) on L1 when binding BzO− or H2PO4− were taken into account to explain the inhibition of the gelation in the presence of BzO−. DFT calculations corroborate this hypothesis and, more importantly, demonstrate considering a trimeric model of the L1 gel that BzO− favours its disruption into monomers inhibiting the gel formation. [ABSTRACT FROM AUTHOR]

• Theoretical and CSD study of Sb•••Te noncovalent bonds. • Pnictogen-Chalcogen bonding competition at both ends of the Te–Sb bond. • QTAIM, NCIPlot and ELF characterization of Sb•••Te interactions. In this manuscript a curious behavior observed in the solid state of several X-ray structures retrieved from the Cambridge structural database (CSD) is described and analyzed. These structures have in common the presence of a metalloid–metalloid pnictogen (Pn)–chalcogen (Ch) covalent bond (i.e., Sb–Te bond) in the structure. The Sb–Te bond presents different σ-holes at both ends of the bond in terms of size and intensity. These compounds have a tendency to form short intermolecular Sb•••Te interactions in the solid state. The aim of this work is to investigate, by using dispersion-corrected density functional theory (DFT-D3) calculations, whether the Sb•••Te contacts observed in the solid state correspond to PnB (Sb is the Lewis acid) or ChB (Te is the Lewis acid). Moreover, using two model stibanyl telluranes, the interaction energies with a series of Lewis bases and anions using both ends of the Sb–Te covalent bond have been computed to investigate which side (PnB or ChB donor) is able to establish stronger interactions with common electron rich atoms. Finally, several computational tools such as the quantum theory of atoms-in-molecules (QTAIM), noncovalent interaction plot (NCIPlot) index and electron localization (ELF) function (2D and 3D maps) have been used to further characterize the physical nature of the Sb•••Te interactions. The results reported herein suggest that in the Sb•••Te contacts the Te atom acts as σ-hole donor and the Sb as electron density donor. [Display omitted]. [ABSTRACT FROM AUTHOR]

The role of perchlorate counter anions and other supra-molecular interaction (in particular CH 3 ···π and Cl···Cl) in the solid state structures of two linear mixed-valence trinuclear centrosymmetric cobalt(III)-cobalt(II)-cobalt(III) complexes with reduced Schiff base ligands have been explained using QTAIM and NCI Plot computational tools. [Display omitted] • Synthesis of two linear mixed-valence trinuclear centrosymmetric cobalt complexes. • Use of malonic acid as anionic co-ligand. • Confirmation of structures vis single crystal X-ray diffraction study. • Analysis of the role CH 3 ···π and Cl···Cl interactions using DFT calculations. • Use of QTAIM and NCI Plot computational tools to characterize the interactions. Two linear mixed-valence trinuclear centrosymmetric cobalt(III)-cobalt(II)-cobalt(III) complexes, [CoII{(μ-L1)(μ-OOCCH 2 COOH)CoIII(DMF)} 2 ](ClO 4) 2 ⋅2DMSO (1) and [CoII{(μ-L2)(μ-OOCCH 2 COOH)CoIII(DMF)} 2 ](ClO 4) 2 ⋅2DMSO (2) have been synthesized using tetradentate N 2 O 2 donor 'reduced Schiff base' ligands, H 2 L1 (2,2-dimethyl-1,3-propanediyl)bis(iminomethylene)bis(phenol) and H 2 L2 (2,2-dimethyl-1,3-propanediyl)bis(iminomethylene)bis(4-chlorophenol), and malonic acid as anionic co-ligand. The complexes have been characterized by spectroscopic measurements and their solid state structures have been determined by single crystal X-ray diffraction analysis. Some supra-molecular assemblies observed in the solid state structures of both complexes have been analysed using DFT calculations, in particular CH 3 ···π and Cl···Cl interactions. QTAIM and NCI Plot computational tools have been used to characterize the interactions. [ABSTRACT FROM AUTHOR]

DFT calculations have been performed to study the mixed valence nature of three linear trinuclear cobalt complexes with tetradentate N 2 O 2 donor reduced Schiff base ligands, and acetate or bezoate as anionic co-ligands. The structure directing role of several noncovalent interactions in the solid state of the complexes has been investigated. [Display omitted] Three linear mixed valence trinuclear cobalt(III)-cobalt(II)-cobalt(III) complexes, [CoII{(μ-L1)(μ-OOCCH 3)CoIII(OOCCH 3)} 2 ]⋅4H 2 O (1), [CoII{(μ-L2)(μ-OOCCH 3)CoIII(OOCCH 3)} 2 ]⋅4H 2 O (2) and [CoII{(μ-L1)(μ-OOCPh)CoIII(OOCPh)} 2 ] (3) , have been synthesized using two N 2 O 2 donor 'reduced Schiff base' ligands, H 2 L1 (2,2-dimethyl-1,3-propanediyl)bis(iminomethylene)bis(4-chlorophenol) and H 2 L2 (2,2-dimethyl-1,3-propanediyl)bis(iminomethylene)bis(4-bromophenol), and acetate or bezoate as anionic co-ligands. The complexes have been characterized by spectroscopic measurements and their solid state structures have been determined by single crystal X-ray diffraction analysis. DFT calculations have been performed to study the mixed valence nature of the complexes. Moreover, the structure directing role of several noncovalent interactions in the solid state of the complexes has been investigated. The interactions have been characterized by a combination of two computational tools based on the topological analysis of the electron density, which are the quantum theory of atoms-in-molecules (QTAIM) and the noncovalent interaction plot, since they are useful to reveal noncovalent interactions in the solid state. [ABSTRACT FROM AUTHOR]

Two new Mn(II) and Zn(II) metal–organic multi-component compounds of anthraquinone-1,5-disulfonate involving energetically significant structure guiding H-bonded assemblies, antiparallel CN⋯CN and aromatic π-stacking interactions. [Display omitted] • Cu(II) and Zn(II) metal–organic multi-component compounds. • Antiparallel CN⋯CN and aromatic π-stacking interactions. • Enclathration of lattice water molecules within supramolecular host cavities. • DFT calculations in combination with NCI plot/QTAIM analysis. • Energetically significant structure-guiding H-bonded assemblies. Two new multi-component coordination compounds of Cu(II) and Zn(II) viz. [Cu(py) 2 (H 2 O) 4 ]ADS·2H 2 O (1) and [Zn(4-CNpy) 2 (H 2 O) 4 ]ADS·2H 2 O (2) (py = pyridine, 4-CNpy = 4-cyanopyridine, ADS = anthraquinone-1,5-disulfonate) have been synthesized in aqueous media at room temperature and characterized using elemental and spectroscopic analyses (FT-IR, electronic), TGA and single crystal X-ray diffraction techniques. Both the compounds crystallize as metal–organic multi-component compounds containing complex cationic moieties along with uncoordinated anionic ADS moieties in the crystal structures. Crystal structure analysis of 1 reveals the stabilisation of the layered assembly of the compound assisted by C H⋯O, O H⋯O hydrogen bonding and π-stacking interactions. Antiparallel CN⋯CN and aromatic π-stacking interactions provide rigidity to the crystal structure of compound 2. In addition, enclathration of lattice water molecules within the supramolecular cavity of 2 provides additional reinforcement to the crystal structure. We have carried out theoretical investigations to analyze π-stacking, H-bonding and antiparallel CN···CN non-covalent interactions observed in the compounds using DFT calculations, quantum theory of atoms in molecules (QTAIM) and non-covalent interaction (NCI) plot index computational tools. The binding energies of the supramolecular assemblies are quite significant due to the ion-pair nature of the interactions which lack directionality; however, the aforementioned weaker non-covalent interactions play crucial roles in the final arrangement of molecules in the solid state due to their directional nature. [ABSTRACT FROM AUTHOR]

• Synthesis of five hydrazinylidene-benzothiazinedione derivatives. • Diverse supramolecular networks of noncovalent interactions. • Assessment of energetic properties of the supramolecular dimers using QTAIM/NCI plot methods. • Compound 9b emerged as the lead inhibitor with strong efficacy. • Molecular docking analysis revealed several key interactions within the active site of urease. The intricate role of noncovalent interactions in numerous fields including chemistry, biology, catalysis, material science, and medicinal chemistry provides a continuous impetus towards the discovery of new synthons that stabilize the supramolecular architectures. In this regard, the current work presents a series of five hydrazinylidene-benzothiazinedione derivatives encompassing a wide plethora of noncovalent interactions. Despite the configurational similarity of their hydrazinylidene-benzothiazinedione component, the five crystallographic packing arrangements of 7a – c and 9a,b are unique. The principal intermolecular interactions are C H⋯O hydrogen bonds and weak C H···π interactions (Malone Type III). Inversion dimers based on C H⋯Cl interactions form for 7b while C H⋯N and C H⋯S interactions in 9a were also observed. Furthermore, the energetic properties of the supramolecular dimers, centrosymmetric (antiparallel oriented) arrangements in 7a and 7b while parallel oriented arrangements in 9a and 9b have been examined using a combined QTAIM/NCI plot methods. The medicinal chemistry potential against urease enzyme revealed compound 9b as the lead inhibitor with strong efficacy (IC 50 = 0.92 ± 0.03 µM). In vitro results were complemented with molecular docking revelations where several key interactions were observed between the potent ligand and active site amino acids. ADMET profile also described compounds 7b and 9b as the best molecules with promising druglike profile. This manuscript presents the synthesis and analysis of noncovalent interactions in hydrazinylidene-benzothiazinediones supported by QTAIM/NCIplot method followed by biochemical and in silico assessment against urease enzyme. [Display omitted] [ABSTRACT FROM AUTHOR]

Synthesis and structural characterization of decavanadates containing cationic organic moiety. DNA binding ability towards CT-DNA and micellization behaviour with CTAB of the complexes were explored. DFT studies performed to analyze the interactions, structural stability of the compounds in solid state. [Display omitted] • Synthesis, characterization, X-ray structure of three decavanadate containing cationic organic moiety. • DNA binding ability towards CT-DNA was explored. • Complexes exhibit increased solubility on interaction with cationic surfactant CTAB. • DFT, QTAIM studies analysed the effective ion pairs, hydrogen bond interaction responsible for formation of supra molecular assemblies, cohesion, and stability of solid state structures of the compounds. Reported here synthesis, structure, DNA binding ability of three decavanadates complexes containing cationic organic moieties, 2-methylimidazolium (1), 4-dimethylaminopyridinium (2) and protonated 3-pyridiniumcarboxamide (3). Compounds are stable solids, characterized by elemental analyses, spectroscopic, single-crystal X-ray diffraction and theoretical studies. X-ray diffraction analysis indicates, the molecular structures of the compounds are composed of ion pairs formed by decavanadate ion [H 2 V 10 O 28 ]4− and the corresponding cationic organic moieties. Complex 1 composed of decavanadate anion in combination with cationic 2-methylimidazolium and 2 contains decavanadate moiety with counter cation protonated 4-dimethylaminopyridine, two DMSO molecules. The structure of 3 consists of [H 2 V 10 O 28 ]4−, protonated 3-pyridinecarboxamide, two co-crystallized neutral organic moieties with two molecules of water. The effective interaction of the ion-pair and hydrogen bonding interaction resulted in the cohesion, stabilization of solid state structure of the complexes. In solid state, compounds present interesting assemblies through the formation of H-bonds analyzed using DFT calculations and quantum theory of "atoms in molecules" (QTAIM). Interaction of the compounds with CT-DNA studied by absorption and fluorescence spectroscopy, show moderately strong intercalative mode of binding. Additionally micellization behaviour of the complexes using surfactant CTAB was studied by conductance measurements and absorption spectroscopy. The complexes show an increased solubility on addition of the surfactant. [ABSTRACT FROM AUTHOR]

The relative importance of the charge assisted NH•••O H-bonds with the CH•••O interactions observed in the solid state structure of a new decavanadate complex have been rationalized. [Display omitted] • Synthesis and characterization of a decavanadate. • Exploration of H-bonding interactions between the bridging O-atoms of the anion and the ammonium groups (N+–H···O) of the ligands. • DFT calculations have been used to rationalize the interactions observed in the solid state. • MEP surface calculations have been used to study the H-bond acceptor ability of the different O-atoms of [V 10 O 28 ]6- anion. In this manuscript, the synthesis and X-ray characterization of a new decavanadate complex, [H 2 L1] 2 [HL2] 2 [V 10 O 28 ] , is reported, where [H 2 L1] and [HL2] are the protonated forms of ligands L1 and L2 [L1 = 4-(2-aminoethyl)morpholine and L2 = N -ethylidene-2-morpholinoethanamine]. H-bonding interactions between the bridging oxygen atoms of the anion and the ammonium groups (N+–H···O) of the ligands are selectively formed. Moreover, a multitude of CH···O interactions are also established between the counter ions. DFT calculations have been used to rationalize the interactions observed in the solid state and to compare the relative importance of the charge assisted NH···O H-bonds with the CH···O ones, evidencing that almost 40 % of the interaction energies are due to CH···O contacts. Moreover, using MEP surface calculations, the H-bond acceptor ability of the different O-atoms of [V 10 O 28 ]6- anion has been studied. To our knowledge, such analysis is unprecedented in the literature. [ABSTRACT FROM AUTHOR]

[Display omitted] This manuscript reports the synthesis, spectroscopic and X-ray characterization of three new vanadium(V) complexes, namely [VO 2 L1] (1) , (μ-O) 2 [V(O)(L2) 2 ]·2CH 3 CN (2) and (μ-O) 2 [V(O)(L3) 2 ]·CH 3 CN (3) [ HL1 (2-ethoxy-6-((quinolin-8-ylimino)methyl)phenol), HL2 (2-(1-(2-(methylamino)ethylimino)propyl)phenol) and HL3 (2-(1-(2-(ethylamino)ethylimino)propyl)phenol)]. Complex 1 is a mononuclear dioxovanadium(V) system containing a five coordinated metal center, whilst complexes 2 and 3 are centrosymmetric dinuclear systems with two [(L)V = O] moieties [(L2)- for 2 and (L3)- for 3 ], which are linked together through asymmetrically bridging oxygen atoms. DFT calculations have been used to rationalize the different behavior of complex 1 , that is related to the lack of strong H-bond donors and strong ability to self-assemble via electrostatically enhanced π-stacking interactions. Moreover, the strength of π–π and CH–π interactions has been evaluated and the interactions have been characterized by several computational tools like MEP, QTAIM and NCI Plot. [ABSTRACT FROM AUTHOR]

• Nitrile pharmacophore is a well-known fragment in various pharmaceuticals. • Crystal engineering of cyclic aminobenzonitriles has been investigated. • Hydrogen bonding and C‒H...π(CN) interactions stabilized the structural topology. • QTAIM/NCIplot computational tool was used to characterize the noncovalent interactions. The essential role of organic crystals in drug development represents a significant research area and remains enduringly topical within the pharmaceutical industry. In the present study, four cyclic aminobenzonitriles 3a-d were prepared through the nucleophilic aromatic substitution reaction of 4-fluorobenzonitrile with various cyclic amines. The synthesized compounds were obtained in moderate to good yields and structurally characterized by FTIR, NMR spectroscopy, mass spectrometry and X-ray crystallography. The crystal packing of these compounds predominantly involves the use of hydrogen bonding interactions (C-H...N, C-H...S, C-H...O) and aromatic contacts (C-H...π(ring & CN), π...π) to govern the complex structural topology. These noncovalent interactions were further evaluated by molecular electrostatic potential (MEP) surface analysis and DFT energy calculations confirming the importance of π-stacking and CH ... π interactions, either involving the arene or the π-system of the cyano groups. These interactions have been further characterized using the QTAIM/NCIplot computational tool. QTAIM and NCIplot analyses of the assembly of compound 3c and the π-π dimer of 3d [Display omitted]. [ABSTRACT FROM AUTHOR]

• Synthesis. • Structural elucidation. • DNA binding. • Dye adsorption properties. • Theoretical studies. Two new copper (II) carboxylates viz. [Cu 2 (μ–2-chlorobenzoato-O,O') 4 (2-methoxybenzaldehyde) 2 ] (1) and [Cu(μ–3,5-dinitrobenzoato-CO,O)(μ–3,5-dinitrobenzoato-NO,O)][Cu 2 (μ–3,5-dinitrobenzoato-CO,O′)](μ1MeOH) 2 (2) containing 2-chlorobenzoic acid and 3,5-dinitrobenzoic acid respectively were synthesized, and characterized by elemental analyses, spectroscopic methods, topological analysis and single crystal XRD studies. Moreover, the synthesized complexes have been screened for the DNA binding ability through UV-Visible and fluorescence spectroscopy indicating moderately strong non-intercalative mode of interaction. Structural studies reveals that compound 1 possesses dinuclear paddle-wheel structure whereas compound 2 is 3D polymer. Asymmetric/monoclinic unit of compound 2 contains a mononuclear unit in combination with a dinuclear entity. DFT calculations combined with QTAIM and NCI plot computational tools have been used to analyze their solid-state supramolecular assemblies focusing on the role of halogen···halogen interactions in 1 and π-hole O···N pnictogen bonding in 2 involving the nitro groups. Finally, the dye adsorption property of the complexes was studied to ascertain their efficacy in removal of toxic dye molecules from aqueous medium. Compound 2 exhibits moderate dye removal efficiency. [Display omitted] [ABSTRACT FROM AUTHOR]

Squaraines are 1,3-disubstituted squaric acid derivatives featuring intense fluorescence in the visible. Unlike their parent compounds, N-squaraines obtained by condensation reaction between squaric acid and primary anilines are non-fluorescent compounds. The incorporation of electron-withdrawing substituents in the para position of the phenyl rings turns these compounds acidic enough to form the corresponding dianions by acid-base reaction with alkaline hydroxide in mixed DMSO-H 2 O solvent mixtures. This work reports the microwave-assisted synthesis of N-squaraines and the investigation of the optical characteristics of their dianions. The dianionic squaraines have a C 4 N 2 O 2 2− squaryl core with absorption maxima at 450–748 nm (molar absorptions up to 7.6 × 104 M−1 cm−1). The N-squaraine dianions are highly fluorescent in the 507–644 nm range (quantum yields 0.18–0.72). Due to their negative charge, and contrary to the expectations, anionic N-squaraines are chemically stable for hours in 50% v/v H 2 O–DMSO solvent mixtures. DFT calculations show the absorption bands are S 0 → S 1 excitations (HOMO → LUMO) and S 1 → S 0 transitions (LUMO → HOMO) for the emission. In both cases, the calculated wavelengths compare well with the experimental observations. [Display omitted] • Discovering the fluorescent behaviour of classical N-squaraines dianions derived from primary anilines. • Aryl rings having electron-withdrawing substituents turn N-squaraines slightly acidic. • N-squaraine dianions can be brightly fluorescent in alkaline dimethylsulfoxide-water solutions. • Experimental and calculated absorption and emission data support a simple HOMO-LUMO excitation-emission pathway. [ABSTRACT FROM AUTHOR]

Three dinuclear cobalt(III/II) mixed valence reduced Schiff base complexes have been synthesized and characterized. Supramolecular assemblies observed in the solid state of the three complexes involving the pseudohalide as electron donors have been analysed using DFT calculations, MEP surfaces and characterized using the NCI Plot index. [Display omitted] Three dinuclear cobalt(III/II) mixed valence reduced Schiff base complexes, [(N 3)CoIIIL(μ-O 2 CR1)CoII(N 3)] ( 1 ), [(SCN)CoIIIL(μ-O 2 CR2)CoII(NCS)] ( 2 ) and [(SCN)CoIIIL(μ-O 2 CR3)CoII(NCS)] ( 3 ) {H 2 L= (2,2-dimethyl-1,3-propanediyl)bis(iminomethylene)bis(6-ethoxyphenol); R1CO 2 H = 4-methyl-3-nitrobenzoic acid; R2CO 2 H = benzoic acid; R3CO 2 H = 3-methyl-4-nitrobenzoic acid} have been synthesized and characterized by elemental analysis and spectral study. X-ray diffraction analysis was used to determine the structures of all three complexes. Spin density calculations have been used to determine the location of the paramagnetic cobalt(II) center in each of the dinuclear complexes. Moreover, several supramolecular assemblies (formed by CH⋯O, CH···SCN and S··· π and other interactions) observed in the solid state of the three complexes involving the pseudohalide as electron donors have been analysed using DFT calculations, molecular electrostatic potential (MEP) surfaces and characterized using the noncovalent interaction plot (NCI Plot) index. [ABSTRACT FROM AUTHOR]

[Display omitted] • [Pb 2 L 2 (CH 3 CN)(ClO 4) 2 ]·2H 2 O (1 ·∙2H 2 O) was obtained from a thiosemicarbazide derivative (HL). • The supramolecular structure of 1 ·∙2H 2 O exhibits Pb∙∙∙N and Pb∙∙∙S tetrel bonds. • In the crystal structure of 1 ·∙2H 2 O tetrel bonds produce a 1D polymeric chain. • The structure of 1 ·∙2H 2 O was validated using a combination of QTAIM and NCIplot tools. In this work, we report on a new lead(II) coordination complex [Pb 2 L 2 (CH 3 CN)(ClO 4) 2 ]·2H 2 O (1 ·2H 2 O), which was readily synthesized from a mixture of Pb(ClO 4) 2 ·3H 2 O and 1-(pyridine-2-yl)benzylidene-4-phenylthiosemicarbazide (HL). The crystal structure analysis of 1 ·2H 2 O evidenced that the lead(II) cation is N , N' , S -chelated by the tridentate pincer type L with formation of a [PbL]+ coordination species, which dimerizes through a couple of reciprocal bridging Pb–S bonds, yielding the [Pb 2 L 2 ]2+ complex cation. The metal centers within this cation are linked by two Pb∙∙∙N tetrel bonds through the bridging acetonitrile molecule with the formation of a [Pb 2 L 2 (CH 3 CN)]2+ building unit. These units are glued by reciprocal Pb∙∙∙S tetrel bonds, yielding a 1D supramolecular polymeric chain. The lead(II) cations interact also with disordered oxygen atoms of both the minor and major occupancies of the perchlorate anions either through covalent Pb–O bonds or Pb∙∙∙O tetrel bonds, respectively. 1D polymeric chains resemble an expanded hexagonal projection and span along the a axis, yielding a grid-like crystal packing, where the cavities are filled by lattice water molecules. The interactions have been studied using DFT calculations and characterized by using the quantum theory of atoms-in-molecules (QTAIM) and the non-covalent interaction plot (NCIplot) computational tools. [ABSTRACT FROM AUTHOR]

• New thiosemicarbazones derived from 5-acetylbarbituric acid were characterized by XRD. • The crystal packing of compounds is directed by non-covalent interactions. • The Hirshfeld surface analysis was also applied to intermolecular interactions • The energetic features of the assemblies were analyzed using DFT calculations A new series of 5-acetylbarbituric based thiosemicarbazones (TSC) named 5-acetylbarbituric hydrazine-1-carbothioamide (1), N-methyl-(5-acetylbarbituric)hydrazine-1-carbothioamide (2), N-ethyl-(5-acetylbarbituric)hydrazine-1-carbothioamide (3), N,N-dimethyl-(5-acetylbarbituric)hydrazine-1-carbothioamide (4), N'-piperidine-(5-acetylbarbituric)-1-carbothiohydrazide (5) and N'-hexamethyleneimine-(5-acetylbarbituric)-1-carbothiohydrazide (6), has been synthesized from 5-acetylbarbituric acid and N-unsubstituted/substituted thiosemicarbazides. The synthesized compounds were well characterized by elemental analyses, FT-IR, 1H, 13C NMR and mass spectroscopic methods. Three-dimensional molecular structures of three compounds (1 ⋅DMSO, 2 and 6 ⋅H 2 O) were determined by single crystal X-ray crystallography, and an analysis of their supramolecular structure was carried out. The supramolecular features of the X-ray structure were also studied using Hirshfeld surface analysis. Finally, H-bonding networks observed in the solid state X-ray structures of 1 ⋅DMSO, 2 , and 6 ⋅H 2 O and unconventional π-stacking dimers in 6 ⋅H 2 O were further analyzed by DFT calculations in combination with molecular electrostatic potential surfaces and combined QTAIM/NCIplot computational tools. [Display omitted] [ABSTRACT FROM AUTHOR]