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Thenovel noncovalent interactions between the charged and neutralaromatic rings and with anions are utilized to design the solid-stateassembly of triply protonated PTPH3(PTP = 4'-(4-pyridyl)-3,2':6',3"-terpyridine)with H2O and three ClO4-,which is synthesized and characterized by single-crystal X-ray diffractionanalysis. Crystallography reveals that the π+-π+, π+-π, and various anion···πinteractions are the major driving forces in the stabilization of the self-assembled structure. In the title complex, a layered assemblyis formed through the mutual influence of π+-π+and π+-π interactions. Theanions are interacting with the charged π-acceptors, which areagain stabilized through π+-π interactions. Therefore, the overall stabilization is governed through π+-π/π-π+, (π+-π+)n, and anion···π+/π+-π/π-π+networks in thesolid state. The interaction energies of the main driving forces observedin the crystal structure have been calculated using density functionaltheory. In addition, the short O···O contact betweenClO4-anions has been analyzed in detailboth computationally and exploring the Cambridge Structural Database. [ABSTRACT FROM AUTHOR]

Three Co(II)-malonate complexes, namely, (C5H7N1)4[Co(C3H1O4)2(H2O)2](NO3)2 (1), (C5H7N2)4[Co(C3H2O4)1(H2O)2](O4)2 (2), and (C5H7N2)4[Co(C3H2O4)2(H2O)1](PF6)1 (3) [C5H,N1 = protonated 2-aminopyridine, C3H4O4 = malonic acid, NO3 = nitrate CIO4 = perchiorate, PF = hexafluorophosphate], have been synthesized from puxely aqueous media, and their crystal structures have been determined by single crystal X-ray diffi-action. A thorough analysis of Hirshfeld surfaces and fingerprint plots facilitates a comparison of intermolecular interactions in 1-3, which are cnacial in building supramolecular architectures. When these complexes are structurally compared with their previously reported analogous Ni(II) or Mg(II) compounds, a very interesting feature regarding the role of counteranions has emerged. This phenomenon can be best described as anion-induced formation of extended supramolecular networks of the type lone pair-л/л-л/,л-anion-л/л-lone pair and lone pair-л/л-л/л-anion involving various weak fortes like lone pafr-л л-л, and anion-л interaction. The strength of these at contacts has been estimated using DFF calculations (M06/6-31+G*), and the formation energy of the supramolecular networks has been also evaluated. The influence of the anion (NO3, CIO4-, and PF6-) on the total interaction energy of the assembly is also studied. [ABSTRACT FROM AUTHOR]

In this article, ab initio calculations have been combined with a search in the Protein Data Bank (PDB) to demonstrate the importance of σ-hole tetrel bonding interactions in biological systems. In particular, we focus our attention on the ability of the -CF3 group to participate in noncovalent interactions as Lewis acids, and we show the importance of this interaction in the inhibition mechanism of a NADP+-dependent isocitrate dehydrogenase (IDH) enzyme that converts isocitrate to α-ketoglutarate. IDH mutations are found in multiple hematologic and solid tumors, inducing premalignant disorders. A potent triazine-based inhibitor of the mutant IDH (enasidenib) presents two-CF3 groups in the structure. One establishes a tetrel bonding interaction with an aspartate residue that contributes to the binding and selectivity of the inhibitor to the active site. [ABSTRACT FROM AUTHOR]

In an unusual reaction of [Pd(L¹)Cl2] (L¹ = 2-(arylazo)pyridine) with amines, a new series of palladium complexes [Pd(L2·-)Cl] (L² = 2-((2-amino)arylazo)pyridine) (1a-1h) were isolated. The complexes were formed via N-H and N-C bond cleavage reactions of 1°/2° and 3° amines, respectively, followed by regioselective aromatic ortho-C-N bond formation reaction and are associated with ortho-C-H/ortho-C-Cl bond activation. A large variety of amines including both aromatic and aliphatic were found to be effective in producing air-stable complexes. Identity of the resultant complexes was confirmed by their X-ray structure determination. Efforts were also made to understand the mechanism of the reaction. A series of experiments were performed, which point toward initial ligand reduction followed by intraligand electron transfer. Examination of the structural parameters of these complexes (1) indicates that the in situ generated ligand coordinated to the PdII center serves as the backbone of these air-stable monoradical complexes. Molecular and electronic structures of the isolated complexes were further scrutinized by various spectroscopic techniques including cyclic voltammetry, variable temperature magnetic susceptibility measurements, electron paramagnetic resonance, and UV-vis spectroscopy. Finally the electronic structure was confirmed by density functional theory calculations. The isolated monoradical complexes adopt an unusual p-stacked array, which leads to a relatively strong antiferromagnetic interaction (J = -40 cm-1 for the representative complex 1c). [ABSTRACT FROM AUTHOR]

FiveM(II)–malonate complexes having a common formula (C6H9N2)4[MII(C3H2O4)2(H2O)2](PF6)2.(H2O)2(1–5) [where C6H9N2= protonated 3-picoline, M(II) = Ni/Co/Mn/Mg/Zn,C3H4O4= malonic acid, and PF6–= hexafluorophospahte], have been synthesizedand their crystal structures have been determined. Complexes 1–5were found to be isostructural andprotonated 3-picoline has primarily mediated the self-assembly process.Role of a discrete water dimer in complexes 1–5was also studied. Weaker π–interactions havealso played crucial role in stabilizing 1D chain constructed by discrete[MII(C3H2O4)2(H2O)2] units. An additional copper complexnamely, (C6H9N2)4[Cu(C3H2O4)2](PF6)2(6) has been synthesized from the same reagentsand was found to have a completely different structure from the others.Structures of all the complexes are fully described and compared here.Moreover, the lone pair−π and π–πnoncovalent interactions have been analyzed by means of DFT calculations,mainly focusing our attention to the influence of the coordinatingmetal on the strength of the interactions and the interplay betweenhydrogen bonding and π-interactions. We also present here Hirshfeldsurface analysis to investigate the close intermolecular contacts. [ABSTRACT FROM AUTHOR]