Polymorphic behavior has significant consequences in solid-state properties relevant to functional materials and pharmaceutical applications. This study reports the single-crystal X-ray structure of a new third unique polymorph of the photoluminescent compound [Cu(dmp)2](BF4) (dmp = 2,9-dimethyl-1,10-phenanthroline). A detailed analysis of how this new polymorph compares with the two previously reported polymorphs was carried out including intramolecular metrics (τ4, twisting, flattening, rocking measures) and intermolecular differences (π-stacking, Hirshfeld surfaces). The new polymorph reported here has larger twisting and flattening distortions from an idealized tetrahedral geometry and the largest displacement of Cu from one dmp plane than the other polymorphs. This new polymorph also exhibits enhanced π-stacking that leads to more dense packing than previous reported polymorphs. Hirshfeld surface comparisons are consistent with a larger percentage of C…C short contacts and lower percentage of C…H contacts present in this new polymorph. The variability of intra- and intermolecular differences within this family of three polymorphs compared demonstrates the large degree of flexibility of both the coordination sphere and packing, even with the expected rigid planar bis-bidentate dmp binding to copper. As the polymorphs each show unique inter- and intramolecular features, differences in solid-state properties including solid-state photoluminescence are expected. This demonstrates the importance of phase purity in the construction of solid-state device applications.

The title compound C15H8BrF6N, was prepared by a condensation reaction of 2-bromo-benzaldehyde and 3,5-bis-(tri-fluoro-meth-yl)aniline in the presence of anhydrous magnesium sulfate. The compound readily crystallizes from a concentrated hexa-nes solution in high yield. The imine bond is nearly planar with the 2-bromo-phenyl group, while the N-(3,5-bis-(tri-fluoro-meth-yl)phenyl moiety is significantly twisted from the imine group [49.61 (5)°]. The crystal packing involves short inter-molecular C-H⋯Br contacts linking zigzag ribbons flanked by fluorous layers.

The synthesis and crystal structure of (E)-N-[(2-bromo­phen­yl)methyl­idene]-3,5-bis­(tri­fluoro­meth­yl)aniline are reported.

The title compound C15H8BrF6N, was prepared by a condensation reaction of 2-bromobenzaldehyde and 3,5-bis(trifluoromethyl)aniline in the presence of anhydrous magnesium sulfate. The compound readily crystallizes from a concentrated hexanes solution in high yield. The imine bond is nearly planar with the 2-bromophenyl group, while the N-(3,5-bis(trifluoromethyl)phenyl moiety is significantly twisted from the imine group [49.61 (5)degrees]. The crystal packing involves short intermolecular C-H center dot center dot center dot Br contacts linking zigzag ribbons flanked by fluorous layers.

The one-step, two-electron reversible reduction of the 6,6′-biazulenic scaffold functionalized along its molecular axis is quantitatively tunable within a wide range of potentials.

The preparation of halogenated benzene-1,2,3,4-tetracarboxylic diimide derivatives is challenging because of the possibility of competitive incorrect cyclizations and SNAr reactivity. Here, we demonstrate that the direct reaction of benzene-1,2,3,4-tetracarboxylic acids with primary amines in acetic acid solvent successfully provides a range of desirable ortho-diimide products in good yields. Furthermore, we demonstrate that sterically challenging N-derivatizations can be readily achieved under microwave reactor conditions, and that SNAr reactivity is only observed when excess amine is used. The halogenated diimides described here are attractive building blocks for organic materials chemistry.

In this work, the encapsulation of [CdBr6]4-by six cations, [Co(dien)2]3+has been described with the help of single crystal X-ray structural study in the complex, mer-[Co(dien)2]2[CdBr6]Br2. The complex anion, [CdBr6]4-has been obtained through solution method while attempting to synthesize complex dianion, [CdBr4]2-. This newly synthesized complex has been initially characterized by elemental analyses and spectroscopic studies (IR, NMR and UV-Visible). IR and NMR studies have been used for the isomeric identification of [Co(dien)2]3+. Single crystal X-ray structure determination has revealed the presence of two complex cations, [Co(dien)2]3+, one complex anion, [CdBr6]4-, and two Br- anions. The complex has crystallized in monoclinic crystal system with space group, P21/n. The study of intermolecular interactions has confirmed the stability of crystal structure through N-H type H-bonding interactions besides electrostatic forces of attraction.

Three new complexes, [Cr(CO(NH2)(2))(6)](PNP)(3)(1), [Cr(CO(NH2)(2))(6)](DNP)(3).3H(2)O (2) , [Cr(CO(NH2)(2))(6)] (TNP)3middot3DMSO (3) (where PNP: 4-nitrophenolate, DNP: 2,4-dinitrophenolate, TNP: 2,4,6-trinitrophenolate) have been synthesized by reacting [Cr(CO(NH2)(2))(6)](DNP)(3).3H(2)O with sodium salts of nitro substituted phenolates (in 1:3 molar ratio) in aqueous medium. The new complexes have been characterized by analytical and spectroscopic studies (FT-IR, UV-Vis). The thermal stability of the complexes has also been determined using thermogravimetric analysis (TGA). The binding property of complex cation, [Cr(CO(NH2)(2))(6)](3)+ with nitrophenolates have been studied using standard UV-vis spectroscopic titrations method in aqueous medium (log beta for PNP:11.9409, DNP:11.3102 and TNP:11.5077). The crystal structure of 3 was determined and it revealed the presence of one cation, three anions and three DMSO molecules. This complex is stabilized by intra-((urea) O center dot center dot center dot H-NH (urea)) and intermolecular H-bonding ((urea) NH center dot center dot center dot OC/ONO (picrate)/ OS (DMSO)) interactions apart from electrostatic forces of attractions. Further, antimicrobial activity of all the complexes has been tested using strain of Gram negative ( E. coli, K. pneumoniae, S. typhi), strain of Gram positive bacteria ( S. epidermidis, B. subtilis) and fungus ( F. moniliforme, A. alternata). Complex 3 shows maximum activity against S. epidermidis and K. pneumoniae although all the compounds are inactive against fungus. (C) 2022 Elsevier B.V. All rights reserved.

N-benzyl-cinchonidinium bromide, C26H29N2O+·Br-, with the systematic name (R)-[(2S,4S,5R)-1-benzyl-5-ethenyl-1-azoniabi-cyclo-[2.2.2]octan-2-yl](quinolin-4-yl)-methanol bromide, is a quaternary ammonium salt of the cinchona alkaloid cinchonidine. This salt is widely used as a chiral phase-transfer catalyst and chiral resolution agent. Both classical and non-classical hydrogen-bonding inter-actions, as well as anion effects have been shown to play key mechanistic roles in the catalysis of cinchona alkaloids. In an effort to understand the effects of water on these inter-molecular inter-actions, the structures of anhydrous N-benzyl-cinchonidinium bromide, (I), and the sesquihydrate, C26H29N2O+·Br-·1.5H2O, (II), were determined.

X-ray structural determinations and computational studies were used to investigate halogen interactions in two halogenated oxindoles. Comparative analyses of the interaction energy and the interaction properties were carried out for Br···Br, C-H···Br, C-H···O and N-H···O interactions. Employing Møller–Plesset second-order perturbation theory (MP2) and density functional theory (DFT), the basis set superposition error (BSSE) corrected interaction energy (Eint(BSSE)) was determined using a supramolecular approach. The Eint(BSSE) results were compared with interaction energies obtained by Quantum Theory of Atoms in Molecules (QTAIM)-based methods. Reduced Density Gradient (RDG), QTAIM and Natural bond orbital (NBO) calculations provided insight into possible pathways for the intermolecular interactions examined. Comparative analysis employing the electron density at the bond critical points (BCP) and molecular electrostatic potential (MEP) showed that the interaction energies and the relative orientations of the monomers in the dimers may in part be understood in light of charge redistribution in these two compounds.

Monoanionic mixed N2P2 donor beta-diketiminate (BDI) ligands with phosphine pendant arms, 2-(4-tolyl)-bis(2-diisopropylphosphinophenyl)propenediimine (abbreviated as Tol-(BDIH)-H-(DIPPP)2), were prepared and metallated with zinc(II) iodide. Three ligand variations have been synthesized by incorporating different substituents (methyl or methoxy) on the linker phenyl rings at positions 4 and 6. In the 4-methyl zinc complex [Tol-(BDIZnI)-Zn-(DIPPMeP)2] and 4-methoxy zinc complex [Tol-(BDIZnI)-Zn-(DIPPMeOP)2], the metal is bound to all four donors on the ligand, rendering a distorted square pyramidal geometry around the zinc metal with tau(5) values of 0.25 and 0.29, respectively. However, the crystal structure of the 4,6-dimethyl zinc complex [Tol-(BDIZnI)-Zn-(DIPPMe2P)2] shows a four-coordinate zinc with only one phosphine bound to the metal, resulting in a distorted seesaw geometry around the metal. While X-ray crystallography shows no interactions between the metal center and the unbound phosphine, solution characterization reveals a symmetrical complex with both phosphines bound to the metal center in all three zinc complexes. (C) 2021 Elsevier Ltd. All rights reserved.

Monodispered ZnO nanocrystals (NCs) were found to quench the fluorescence of two donor-pi system-acceptor (D-pi-A) dyes; (E)-2-cyano-3-[5-[4-(diethylamino)phenyl]thiophen-2-yl]-2-propenoic acid, 1, and its furan analogue, 2. Parameters based on single crystal X-ray crystallography and DFT calculations confirmed planar structures for both dyes and delocalization of the donor nitrogen electrons into the pi-system. Both dyes exhibited a quasi-reversible one-electron oxidation with E degrees values of 0.39 and 0.35 V for 1 and 2, respectively, versus the ferrocene/ferrocenium redox couple, and spectroelectrochemical measurements revealed the absorption spectra of the oxidized products. In stark contrast to earlier reports of related dyes that did not bear a strong donor substituent, the ZnO nanocrystal fluorescence quenching efficiency was nearly quantitative. Adsorption isotherms revealed equilibrium binding constants 2.5(0.5) X 10(5) and 8(1) x 10(5) M-1 for 1 and 2, respectively, and large values for the maximum number of dyes per nanocrystal. Ultrafast fast pump-probe measurements of 1 and 2 in CH2Cl2 revealed formation of singlet excited states that decayed with lifetimes of 1660(30) and 1600(100) ps, respectively. Addition of an equimolar amount of ZnO NCs caused the singlet excited state of each dye to disappear with concurrent formation of the spectral signatures for the corresponding oxidized products, thus allowing the assignment of the process to an excited state electron transfer to the ZnO NCs. Electron transfer lifetimes for 1 ranged from 14.8(4) to 18.2(6) ps as the ZnO NC diameter decreased from 5.0 to 3.2 nm, while for 2 the lifetimes ranged from 11.1(3) to 9.5(3) ps for a similar change in ZnO NC diameters. The weak dependence of the excited state electron transfer lifetimes on the diameter of the NCs is consistent with a reaction dominated by changes in their size-dependent density of states.

Advanced precursors to novel ferrocene-based ligands Cp2FeC(O)CH(R)C(O)CH3 (R = benzyl, allyl) were synthesized from 1-ferrocenylbutane-1,3-dione via active methylene chemistry. Crystal structures were obtained and computational studies carried out to explore the structural features of these new compounds. Addition of carbonyl electrophiles resulted in the formation of unexpected products, which were identified and mechanisms for their formation proposed. (C) 2020 Elsevier Ltd. All rights reserved.

A metal/ligand cooperative approach to the reduction of small molecules by metal silylene complexes (R2 Si=M) is demonstrated, whereby silicon activates the incoming substrate and mediates net two-electron transformations by one-electron redox processes at two metal centers. An appropriately tuned cationic pincer cobalt(I) complex, featuring a central silylene donor, reacts with CO2 to afford a bimetallic siloxane, featuring two CoII centers, with liberation of CO; reaction of the silylene complex with ethylene yields a similar bimetallic product with an ethylene bridge. Experimental and computational studies suggest a plausible mechanism proceeding by [2+2] cycloaddition to the silylene complex, which is quite sensitive to the steric environment. The CoII /CoII products are reactive to oxidation and reduction. Taken together, these findings demonstrate a strategy for metal/ligand cooperative small-molecule activation that is well-suited to 3d metals.

Pincer-type [P2Si]Rh complexes featuring a rhodium–silicon bond are shown to facilitate well-defined stoichiometric reductions of CO2 with Si–O bond formation by two different pathways: (a) hydride transfer to CO2 followed by formate migration to silicon, or (b) complete scission of the C═O bond at the Rh–Si unit to afford a product with siloxide and carbonyl ligands. A combined experimental and computational study shows that the latter process occurs by anomalous insertion of CO2 into the polarized Rhδ−–Siδ+ bond, a finding that is confirmed by extending the reactivity to an unchelated system. The siloxide carbonyl product can be further elaborated by reaction with water or pinacolborane to give structurally distinct CO2 reduction products. Taken together, these results demonstrate how metal/main-group bonds can be tuned to direct migratory insertion reactivity.

The synthesis and characterization of a series of cyclometallated complexes of Pd(ii) incorporating the mixed donor ligand 1-oxa-4,7-dithiacyclononane ([9]aneS2O) are presented in this study. Complexes of the form [Pd(C^N)([9]aneS2O)](PF6) (C^N = 2-phenylpyridine (ppy) 1b, 4-(2-pyridyl)benzaldehyde (ppyCHO) 2b, 7,8-benzoquinoline (bzq) 3b, 2-benzothienylpyridine (btp) 4b, 2-phenylbenzothiazole (pbt) 5b), were obtained in high-yield from a simple two-step synthetic scheme. All of these complexes were fully characterized by NMR, ESI-MS, IR, combustion analyses, and most (1b, 2b, 4b, 5b) by X-ray crystallography. Solution 1H and 13C NMR studies of [Pd(C^N)([9]aneS2O)](PF6) complexes demonstrate complicated [9]aneS2O behavior at room temperature. Variable temperature NMR reveals dynamic bonding of the [9]aneS2O ligand consistent with the presence of both endodentate and exodentate bonding modes. This is in stark contrast to the related [9]aneS3 (1,4,7-trithiacyclononane) cogeners that demonstrate fluxional endodentate bonding only in solution. X-ray structures reveal only exodenate [9]aneS2O bonding in this series, unlike the related [9]aneS3 complexes that show endodenate bonding with an axial PdS interaction. DFT calculations performed on endo and exo [9]aneS2O bonding forms of 4b, as well as a transition state calculation for interconversion, suggest reasonable access to both bonding forms based on the energy barrier. Natural bond order calculations provide further evidence for a weak axial PdO interaction in the endo form of 4b.

Reactions between 3,4-propylenedioxythiophenes (ProDOTs) and N-alkyl isatins under ambient conditions result in isomerically pure indophenine materials as confirmed by TLC and 1H NMR analysis. The resulting low band gap materials exhibit favorable inter- and intramolecular interactions, high thermal stabilities, low energy electronic transitions, and amphoteric redox behavior.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.