Search results for "BOND"
showing 10 items of 3527 documents
Achieving Strong Positive Cooperativity through Activating Weak Non-Covalent Interactions
2018
Positive cooperativity achieved through activating weak non-covalent interactions is common in biological assemblies but is rarely observed in synthetic complexes. Two new molecular tubes have been synthesized and the syn isomer binds DABCO-based organic cations with high orientational selectivity. Surprisingly, the ternary complex with two hosts and one guest shows a high cooperativity factor (α=580), which is the highest reported for synthetic systems without involving ion-pairing interactions. The X-ray single-crystal structure revealed that the strong positive cooperativity likely originates from eight C-H⋅⋅⋅O hydrogen bonds between the two head-to-head-arranged syn tube molecules. Thes…
A nucleophilic gold complex.
2019
Solid-state auride salts featuring the negatively charged Au– ion are known to be stable in the presence of alkali metal counterions. While such electron-rich species might be expected to be nucleophilic (in the same manner as I–, for example), their instability in solution means that this has not been verified experimentally. Here we report a two-coordinate gold complex (NON)AlAuPtBu3 (where NON is the chelating tridentate ligand 4,5-bis(2,6-diisopropylanilido)-2,7-di-tert-butyl-9,9-dimethylxanthene) that features a strongly polarized bond, Auδ––Alδ+. This is synthesized by reaction of the potassium aluminyl compound [K{Al(NON)}]2 with tBu3PAuI. Computational studies of the complex, includ…
Synthesis, X-ray structure, Hirshfeld analysis, and DFT studies of a new Pd(II) complex with an anionic s-triazine NNO donor ligand
2020
Abstract A new Pd(II) complex, [Pd(Triaz)Cl], with the hydrazono-s-triazine ligand, 2,4-di-tert-butyl-6-((2-(4-morpholino-6-(phenylamino)-1,3,5-triazin-2-yl)hydrazono)methyl)phenol (HTriaz), was synthesized by the reaction of PdCl2 with the organic ligand (1:1) in acetone under isothermal conditions. The molecular structure of the [Pd(Triaz)Cl] complex was determined using FTIR and 1H NMR spectroscopic techniques, and single-crystal X-ray diffraction. Moreover, using Hirshfeld surface analysis, the percentages of the intermolecular interactions were determined. The obtained values were 60.6%, 11.6%, 8.1%, 3.6%, and 5.0% for the H⋯H, C⋯H, O⋯H, N⋯H, and Cl⋯H interactions, respectively. Among …
A robust nanoporous supramolecular metal–organic framework based on ionic hydrogen bonds
2014
International audience; Hydrogen-bond assembly of tripod-like organic cations [H3-MeTrip]3+ (1,2,3-tri(4′-pyridinium-oxyl)-2-methylpropane) and the hexa-anionic complex [Zr2(oxalate)7]6− leads to a structurally, thermally, and chemically robust porous 3D supramolecular framework showing channels of 1 nm in width. Permanent porosity has been ascertained by analyzing the material at the single-crystal level during a sorption cycle. The framework crystal structure was found to remain the same for the native compound, its activated phase, and after guest resorption. The channels exhibit affinities for polar organic molecules ranging from simple alcohols to aniline. Halogenated molecules and I2 …
Cleavage of Ge–Ge and Sn–Sn Triple Bonds in Heavy Group 14 Element Alkyne Analogues (EAriPr4)2 (E = Ge, Sn; AriPr4 = C6H3-2,6(C6H3-2,6-iPr2)2) by Rea…
2016
The reactions of heavier group 14 element alkyne analogues (EAriPr4)2 (E = Ge, Sn; AriPr4 = C6H3-2,6-(C6H3-2,6-iPr2)2) with the group 6 transition-metal carbonyls M(CO)6 (M = Cr, Mo, W) under UV irradiation resulted in the cleavage of the E–E triple bond and the formation of the complexes {AriPr4EM(CO)4}2 (1–6), which were characterized by single crystal X-ray diffraction as well as by IR and multinuclear NMR spectroscopy. Single-crystal X-ray structural analyses of 1–6 showed that the complexes have a nearly planar rhomboid M2E2 core with three-coordinate group 14 atoms. The coordination geometry at the group 6 metals is distorted octahedral formed by four carbonyl groups as well as two br…
Concerted Halogen-Bonded Networks with N-Alkyl Ammonium Resorcinarene Bromides: From Dimeric Dumbbell to Capsular Architectures
2015
N-Alkyl ammonium resorcinarene bromides and 1,4-diiodooctafluorobutane via multiple intermolecular halogen bonds (XB) form different exotic supramolecular architectures through subtle changes of the upper rim substituents. Dimeric dumbbell-like assembly with encapsulated guest molecules is generated with N-benzyl substituents. The N-hexyl groups engender an XB-induced polymeric pseudocapsule and an XB-induced dimeric capsule with entrapped 1,4-dioxane guest molecules. The N-propyl and N-cyclohexyl groups generate deep cavity cavitands. The deep cavity cavitands possess cavities for self-inclusion leading to polymeric herringbone arrangement in one direction and that pack into 3D polymeric a…
Two Polymorphic Forms of a Six-Coordinate Mononuclear Cobalt(II) Complex with Easy-Plane Anisotropy: Structural Features, Theoretical Calculations, a…
2016
A mononuclear cobalt(II) complex [Co(3,5-dnb)2(py)2(H2O)2] {3,5-Hdnb = 3,5-dinitrobenzoic acid; py = pyridine} was isolated in two polymorphs, in space groups C2/c (1) and P21/c (2). Single-crystal X-ray diffraction analyses reveal that 1 and 2 are not isostructural in spite of having equal formulas and ligand connectivity. In both structures, the Co(II) centers adopt octahedral {CoN2O4} geometries filled by pairs of mutually trans terminal 3,5-dnb, py, and water ligands. However, the structures of 1 and 2 disclose distinct packing patterns driven by strong intermolecular O-H···O hydrogen bonds, leading to their 0D→2D (1) or 0D→1D (2) extension. The resulting two-dimensional layers and one-…
Competitive NH···Ru/Fe Hydrogen Bonding in Ferrocenyl Ruthenocenyl Tosyl Hydrazone
2016
A strong nonclassical NH···Fe intramolecular hydrogen bond (IHB) is present in the literature-known diferrocenyl tosyl hydrazone (1). Here, we confirm by NMR and IR spectroscopy as well as by XRD methods that an analogous NH···Ru IHB is present in the heavier homologue diruthenocenyl tosyl hydrazone (2). The NH···Ru IHB in 2 is stronger than the NH···Fe IHB in 1 by 6 kJ mol–1, as determined by IR spectroscopy. Further, we probed the E/Z isomer directing abilities of NH···M IHBs in the synthesis of the mixed metallocenyl compound ferrocenyl ruthenocenyl tosyl hydrazone (3). 3 is obtained as a mixture of the Z and E isomers (3a,b) with NH···Ru and NH···Fe IHBs, respectively. At 111 °C, 3a is …
Highly Functionalized Brønsted Acidic/Lewis Basic Hybrid Ferrocene Ligands: Synthesis and Coordination Chemistry
2019
International audience; A general challenging issue in the synthesis of hemilabile ferrocene ligands is the access to highly functionalized ferrocene starting materials. These can bear donor/acceptor atoms, additional functional and structuring spectator substituents, but the preparation of such species poses general synthetic difficulties. We report herein alternative synthetic routes to hybrid ferrocene donors such as tert-butylated phosphanylcarboxylic acids and their corresponding aldehydes. These hybrid ambiphilic species that combine Brønsted-acidic and Lewis-basic functional moieties in their structure were characterized by multinuclear NMR and single-crystal X-ray diffraction analys…
Intermolecular interactions in dictating the self-assembly of halogen derivatives of bis-(N-substituted oxamato)palladate(ii) complexes
2016
Three palladium(II) complexes of formula (n-Bu4N)2[Pd(4-Fpma)2] (1), (n-Bu4N)2[Pd(4-Clpma)2]·4H2O (2) and (n-Bu4N)2[Pd(4-Brpma)2]·4H2O (3) [n-Bu4N+ = tetra-n-butylammonium cation, 4-Fpma = N-4-fluorophenyloxamate, 4-Clpma = N-4-chlorophenyloxamate and 4-Brpma = N-4-bromophenyloxamate] have been prepared and their structures determined by single crystal X-ray diffraction. Each palladium(II) ion in 1–3 is four-coordinate with two oxygen and two nitrogen atoms from two fully deprotonated oxamate ligands building PdO2N2 square planar surroundings, the oxamate ligands exhibiting trans (1 and 2) and cis (3) dispositions. The fluoro substituent and the organic counterion in 1 are involved in C–H⋯F…