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Benzoylhydrazone Schiff base–ligated three new ONO pincer–type palladium(II) complexes, [(PdL1(PPh3)] (1), [(PdL2(PPh3)] (2), and [(PdL3(PPh3)] (3), were synthesized by the reaction of the respective ligand, N-(2-hydroxybenzylidene)benzohydrazide (HL1), N-(2-hydroxy-3-methoxybenzylidene)benzohydrazide (HL2), or N-(5-bromo-2-hydroxybenzylidene) benzohydrazide (HL3), with Pd(OAc)2 and PPh3 in methanol and isolated as air-stable reddish-orange crystalline solids in high yields (78%–83%). All three complexes were fully characterized by elemental analysis, Fourier-transform infrared spectroscopy, UV–Visible, 1H nuclear magnetic resonance (NMR), 13C{1H} NMR, and 31P{1H} NMR spectroscopic studies. The molecular structure of all three complexes was established unambiguously by single-crystal X-ray diffraction studies which revealed a distorted square planar geometry of all three complexes. The ONO pincer–type ligands occupied three coordination sites at the palladium, while the fourth site is occupied by the monodentate triphenylphosphine ligand. The catalytic potential of all three complexes was explored in the carbonylative Suzuki coupling of aryl bromides and iodides with arylboronic acids to yield biaryl ketones, using CHCl3 as the source of carbonyl. The reported protocol is convenient and safe as it obviates the use of carbon monoxide (CO) balloons or pressured CO reactors which are otherwise needed for the carbonylation reactions. The methodology has been successfully applied to the synthesis of two antineoplastic drugs, namely, phenstatin and naphthylphenstatin, in good yields (81% and 85%, respectively). Under the optimized reaction conditions, complex 2 exhibited the best catalytic activity in the carbonylative Suzuki couplings. The reported catalysts have wide reaction scope with good functional group tolerance. All catalysts could be retrieved from the reaction after completion and recycled up to three times with insignificant loss in the catalytic activity. © 2020 John Wiley & Sons, Ltd.

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Applied Organometallic Chemistry

Carbonylative Suzuki coupling reactions catalyzed by ONO pincer–type Pd(II) complexes using chloroform as a carbon monoxide surrogate

Glycerol can be converted to valuable products such as epichlorohydrin which is an important intermediate applied in various industries. For example, dioxane derivatives, which are important pharmaceuticals, can be obtained from epichlorohydrin. In the present study, ZIF-8, ZIF-67, MIL-100, and UiO-66 were applied for the direct cyclodimerization of epichlorohydrin. These MOFs were selected because they were already applied as active catalysts in ring opening of epoxides. Among them, ZIF-8 showed the highest activity and selectivity in the absence of any solvent or co-catalyst. Using ZIF-8 as a catalyst, the cyclodimer product (1,4-dioxane 2,5-bis-chloromethyl) was obtained in a yield of about 70% which was significantly superior to previous homo or heterogeneous catalysts for this reaction. Due to ZIF-8 structure and the proposed mechanism, the cyclodimerization reaction catalyzed either by the defects in the structure and/or on the surface. Furthermore, acidic-basic characteristics were also in play. The NH3 and CO2 temperature-programed desorption technique were utilized to identify the active sites and thereby reaction mechanism. Moreover, because of similar properties of ZIF-8 to zeolites, the activity of commercial ZSM-5 for the same reaction was also investigated in this work. © 2017 The Authors

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Arabian Journal of Chemistry

Selective cyclodimerization of epichlorohydrin to dioxane derivatives over MOFs

The activated cluster Os3(CO)10(CH3CN)2 (1) reacts readily with a number of carboxylated chalcones and benzaldehydes (2a−j) to afford products with the general formula Os3(CO)10(µ-H)(µ-O2CR) (3a–j). The structures of all the novel clusters have been characterized by IR and 1H NMR spectroscopy, as well as mass spectrometry and elemental analysis. Single-crystal X-ray diffraction analysis has also been carried out for one of the carboxylated chalcones and two of the derivatized clusters. The activity of some of the derivatized clusters against the ER+ breast carcinoma MCF-7 cancer cell line has also been evaluated. © 2019, Springer Science+Business Media, LLC, part of Springer Nature.

Journal of Cluster Science

Carboxylated Chalcone and Benzaldehyde Derivatives of Triosmium Carbonyl Clusters: Synthesis, Characterization and Biological Activity Towards MCF-7 Cells

Three new coordination polymers, [NaI(H2L)(H2O)3]n (1), {[KI(H2L)(H2O)]8·13H2O}n (2), and {[NiIINaI2(HL)2(H2O)8]·6H2O}n (3), were assembled from 1,3-dimethyl-5-(p-sulfonic-phenylazo)-6-aminouracil (H3L) as a versatile building block. Although azo-coupling reactions generally result in simple azo-compounds, the presence of the sulfonate (-SO3-) group at the ligand frame led to the formation of the NaI-1D (1) or KI-3D (2) homometallic coordination polymer with different ligand coordination modes. Moreover, the heterometallic NiII/NaI-1D (3) coordination polymer was obtained while carrying the reaction of 2 with NiCl2·6H2O. The structures of the obtained products were fully established by single crystal X-ray diffraction and confirmed by standard methods. Compounds 1 and 3 possess 1D metal-organic chains with the 2C1 topology, whereas 2 features a very complex 3D metal-organic architecture with an unprecedented topology. The computational study for molecular electrostatic potential (MEP) surface energies revealed an important finding, namely a decrease of the π-acidity of the uracil ring upon coordination and a consequent increase of the π-basicity of the phenyl-sulfonate ring, resulting in effective anti-parallel π-π stacking interactions in 1 and 2. Finally, a semi-conductive behavior of the obtained compounds was explored using impedance spectroscopy, revealing the very remarkable conductive properties of 1 (2.2 × 10-4 S cm-1), which is a far better conductive material than 2 (7.2 × 10-6 S cm-1) and 3 (4.8 × 10-7 S cm-1). The obtained products represent the first coordination compounds derived from H3L. This study contributes to the design of functional coordination polymers driven by still poorly explored 6-aminouracil building blocks. © 2020 The Royal Society of Chemistry.

CrystEngComm

Metal-organic architectures driven by a multifunctional 6-aminouracil spacer: Structures, noncovalent interactions, and conductivity

The dianionic cluster [Os10(µ6-C)(CO)24]2− reacts with excess SbX3 or p-tolylSbX2 to form the monoanionic clusters [Os10{µ4-Sb(p-tolyl)nX2-n}(µ6-C)(CO)24]− (n = 0; X = Cl, I; n = 1, X = Cl) via insertion into an Os–Os bond. Further insertion into an Os–Os bond occurs when they are reacted further with excess iodine. The chemistry and structure of these clusters can be understood in terms of the isolobal analogy between [Sb(p-tolyl)nX2-n)]+ and I+. © 2020, Springer Science+Business Media, LLC, part of Springer Nature.

Reaction of the Decaosmium Carbido Cluster [Os10(µ6-C)(CO)24]2− with Halostibines

A sequence of aroyl selenourea ligands (L1–L3) substituted by aniline and their Ru(II) (η6-p-cymene) complexes (1-3), [Ru(II) (η6-p-cymene) L] (L = monodentate aroyl selenourea ligand) have been synthesized and characterized the composition of the ligands and their metal complexes. The molecular structures of ligand L1 and complex 3 were also confirmed by single XRD crystal method. The single-crystal XRD study showed that aroyl selenourea ligand coordinates with Ru via Se novel neutral monodentate atom. In vitro DNA interaction studies were investigated by Fluorescence and UV-Visible spectroscopic methods which showed that the intercalative mode of binding is in the order of 1 &gt; 2 &gt; 3 with Ru(II) (η6-p-cymene) complexes. Spectroscopic methods have been used for measuring the binding affinity of bovine serum albumin to complex. Moreover, the cytotoxic study of complexes (1–3) were evaluated against HeLa S3, A549, and IMR90 cells, resulting in complexes 1 and 2 showed promising cytotoxic activity against HeLa S3 cell with IC50 values of 24 and 26 µM, respectively. Also, the morphological changes of HeLa S3 and A549 cells were confirmed by fluorescence microscope in the presence of complexes 1 and 2 using AO (acridine orange, 200 µM) and EB (ethidium bromide, 100 µM). In addition, the docking results strongly support the protein binding studies of the complexes. Communicated by Ramaswamy H. Sarma. © 2020, © 2020 Informa UK Limited, trading as Taylor & Francis Group.

Journal of Biomolecular Structure and Dynamics

Synthesis, characterization, theoretical, molecular docking and in vitro biological activity studies of Ru(II) (η6-p-cymene) complexes with novel aniline substituted aroyl selenoureas

In the field of homogeneous catalysis, particularly in anti-Markovnikov hydration, sterically demanding phosphine ligand has found to be very effective. Here we report the crystal structure of a phosphine-imidazolium salt which crystallized in monoclinic space group P21/c with a = 16.6623(13) (Å), b = 10.6686(8) (Å) and c = 12.8916(11) with β = 110.232(2). Hirshfeld surface analysis show that the halogen–hydrogen interaction leads to a formation of 1D chain. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.

MolBank

Synthesis, structure and hirshfeld surface analysis of phosphine–imidazolium salt

A Facile Modular Addition Approach to Size Control in the Synthesis of Oxo Bridged Phosphazane Macrocycles

Carbodicarbenes (CDCs) possess two lone pairs of electrons on their central carbone C atom (Ccarbone). Coordination to a transition metal via a σ bond leaves one pair of electrons with appropriate symmetry for πdonation to the metal. However, the high energy of the latter also renders the CDC ligand potentially redox-active. Herein, we explore these alternatives in the redox series [Cr(L)2]n+ and [Co(L)2]n+ (n = 2-5), where L is a tridentate ligand comprised of a central CDC and two flanking pyridine donors. To this end, all members of both redox series were synthesized and their electronic structures were investigated by using a combination of 1H NMR, Evans' NMR, IR, UV-vis, and EPR spectroscopies, SQUID magnetometry, X-ray crystallography, and density functional theory studies. Whereas [CoII(L)2]2+ is a straightforward low-spin (S = 1/2) cobalt(II) complex, the corresponding chromium complex was found to feature an electronic structure that is intermediate between the two limiting resonance forms [CrIII(L•-)(L)]2+ and [CrII(L)2]2+. In the case of the tri-, tetra-, and pentacationic complexes, the qualitatively identical electronic structures [MIII(L)2]3+, [MIII(L•+)(L)]4+, and [MIII(L•+)2]5+ were observed for both metals. Thus, the metal ions retain a 3+ oxidation state throughout, and the higher redox states contain oxidized ligands. The majority of the unpaired spin on the cation radical ligands was calculated to be localized in π-symmetry orbitals on the coordinated Ccarbone atoms. Analogous behavior was previously reported for the corresponding iron redox series and, as such, redox noninnocence in oxidized CDC and, more broadly, carbone complexes is likely widely accessible. © 2020 American Chemical Society.

Inorganic Chemistry

Carbodicarbene Ligand Redox Noninnocence in Highly Oxidized Chromium and Cobalt Complexes

We report on the synthesis and structural features of NMe2-modified β-diketiminate-supported boron difluoride compounds (LArBF2: LAr = [HC(NAr)2(CNMe2)2]-; LPh: Ar = Ph; LTol: Ar = p-tolyl; LXyl: Ar = m-xylyl). The title compounds were prepared in moderate yields (∼65 \%) by in situ deprotonation of the corresponding ligands LArH using KH, followed by the addition of BF3OEt2. According to solid-state and theoretical analyses of the BF2 compounds, the lone pair at each NMe2 group is involved in electron delocalization within the central BC3N2 ring. As a result, the N-aryl substituents sterically clash with the NMe2 groups, causing this central ring to pucker. Several attempts were made to prepare heavy analogues (e.g. LArBX2, X = Cl, Br, I) but only unidentifiable product mixtures were observed. It appears that the observed steric clash between the N-aryl substituents and the NMe2 groups prevented the formation of these heavy analogues. © 2020 CSIRO.