trans-Tetra­aqua­bis­[1,3-bis­(4-pyrid­yl)propane-κN]cobalt(II) biphenyl-4,4′-disulfonate monohydrate

In the title compound, [Co(C13H14N2)2(H2O)4](C12H8O6S2)·H2O, the cation, anion and uncoordinated water mol­ecule have crystallographically imposed twofold symmetry. The cobalt(II) atom exhibits a slightly distorted octa­hedral coordination geometry provided by two N atoms from two 1,3-bis­(4-pyrid­yl)propane ligands and the O atoms from four water mol­ecules. The dihedral angle between the pyridine rings in the ligand is 86.14 (11)°, whereas the dihedral angle formed by the symmetry-related benzene rings in the anion is 35.81 (12)°. In the crystal, cations, anions and water mol­ecules are linked into layers parallel to the ac plane by O—H⋯O and O—H⋯N hydrogen-bond inter­actions. The layers are further connected into a three-dimensional network by C—H⋯O hydrogen bonds

Predicting melting points of organic molecules : applications to aqueous solubility prediction using the General Solubility Equation

In this work we make predictions of several important molecular properties of academic and industrial importance to seek answers to two questions: 1) Can we apply efficient machine learning techniques, using inexpensive descriptors, to predict melting points to a reasonable level of accuracy? 2) Can values of this level of accuracy be usefully applied to predicting aqueous solubility? We present predictions of melting points made by several novel machine learning models, previously applied to solubility prediction. Additionally, we make predictions of solubility via the General Solubility Equation (GSE) and monitor the impact of varying the logP prediction model (AlogP and XlogP) on the GSE. We note that the machine learning models presented, using a modest number of 2D descriptors, can make melting point predictions in line with the current state of the art prediction methods (RMSE ≥ 40 oC). We also find that predicted melting points, with an RMSE of tens of degrees Celsius, can be usefully applied to the GSE to yield accurate solubility predictions (log10S RMSE < 1) over a small dataset of druglike molecules.PostprintPostprintPeer reviewe

Entangled Two-Dimensional Coordination Networks: A General Survey

Many of the reported species exhibit the intriguing feature of interpenetration or other types of entanglements. The properties of these materials are related not only to their molecular structures but also to the topology of the individual networks as well as to the way in which the individual nets are entangled. Different synthetic procedures have been developed to attain a certain control of entanglement in coordination networks, and recently some reviews have appeared that are focused on factors governing the entanglements, having in mind their potential applications. However, these analyses are mostly devoted to 3D networks thanks to the great wealth of data on interpenetration. Simplification of a network that contains 2-loops can lead to complete disappearance of the entanglement, and therefore such networks were picked out into a separate group

Complementarity and preorganisation in the assembly of heterometallic-organic cages via the metalloligand approach : recent advances

The design of new metallocage polyhedra towards pre-determined structures can offer both practical as well as intellectual challenges. In this mini-review we discuss a selection of recent examples in which the use of the metalloligand approach has been employed to overcome such challenges. An attractive feature of this approach is its stepwise nature that lends itself to the design and rational synthesis of heterometallic metal–organic cages, with the latter often associated with enhanced functionality

Nanosized Supramolecular Coordination Polymers Derived from Divalent Metal Ions, 4-Pyridylacetate and Auxiliary Ligands Containing Nitrogen and Phosphorus Donors

A series of coordination polymers of Co(II), Ni(II), Cu(II) or Cd(II) comprising 4-pyridylacetate (pya) and certain auxiliary ligands including benzimidazole (Hbzim), 1,10-phenanthroline (phen), 2,2'-bipyridine (2,2'-bipy),&nbsp; 2-amino-4-methylthiazole (A-Mtz), quinazole (Quz), 2,5-dimethylpyrazine (dpmz), bis(diphenylphosphino)methane (dpm), 1,2-bis(diphenylphosphino)ethane (dpe) and 1,3-bis(diphenylphosphino) propane (dpp) were prepared&nbsp; and characterized by spectroscopic, magnetic and&nbsp; thermal techniques. In these coordination polymers 4-pyridylacetate coordinates to the metal ions in a monodentate fashion through the carboxylate oxygens and/or the pyridyl nitrogen. Octahedral structures around the metal ions were suggested for all the complexes. The kinetic analyses of the thermal decomposition of the complexes were studied using the Coats-Redfern equation. The kinetic and thermodynamic parameters of the thermal decomposition were also calculated and discussed. From the X-ray powder diffraction data, the crystal parameters as well as the particle sizes (15.7-18.7 nm) of the complexes could be evaluated. Some of the compounds exhibit catalytic activity. The biological activity of the compounds was screened as well. DOI:&nbsp;http://dx.doi.org/10.17807/orbital.v13i1.155

Two new 1D coordination polymers: syntheses, structures and properties

Two new coordination polymers, namely, [Zn(bi)(Cl)2]n (1) and [Cu(L)2(bib)(H2O)2]n (2) (bi = 4,4'-bis(2-methylimidazol-1-ylmethyl)biphenyl; L = 4-(2-(4-(methoxycarbonyl)phenoxy)ethoxy)benzoic acid and bib = 2,3-bis(4-pyridyl)butane), are synthesized and characterized. Both of 1 and 2 have 1D covalent chains, which show different conformally chain feature. 2D supremolecular rhombic and rectangle motifs are observed in 1 and 2, respectively. The O–H···O and C–H···Cl hydrogen-bonding interactions play a significant role in promoting the diversity of structural patterns. KEY WORDS: Structure, Supramolecular interaction, Luminescence Bull. Chem. Soc. Ethiop. 2014, 28(3), 415-422.DOI: http://dx.doi.org/10.4314/bcse.v28i3.1

Magic of alpha : the chemistry of a remarkable bidentate phosphine, 1,2-bis(di-tert-butylphosphinomethyl)benzene

We thank the Fonds der Chemischen Industrie for a Kekulé Fellowship for a studentship and the Deutsche Forschungsgemeinschaft (DFG, project number 424535516) for support (J.V.). We are also very grateful to Lucite International for funding the work in St Andrews that is contained in this review.The bidentate phosphine ligand 1,2-bis(di-tert-butylphosphinomethyl)benzene (1,2-DTBPMB) has been reported over the years as being one of, if not the, best ligands for achieving the alkoxycarbonylation of various unsaturated compounds. Bonded to palladium, the ligand provides the basis for the first step in the commercial (Alpha) production of methyl methacrylate as well as very high selectivity to linear esters and acids from terminal or internal double bonds. The present review is an overview covering the literature dealing with the 1,2-DTBPMB ligand: from its first reference, its catalysis, including the alkoxycarbonylation reaction and its mechanism, its isomerization abilities including the highly selective isomerizing methoxycarbonylation, other reactions such as cross-coupling, recycling approaches, and the development of improved, modified ligands, in which some tert-butyl ligands are replaced by 2-pyridyl moieties and which show exceptional rates for carbonylation reactions at low temperatures.PostprintPeer reviewe

Mono- and Binuclear Chloride and Bromide Complexes of Bi(III) with Double-Charged Cations Based on Pyridine: Syntheses and Crystal Structures

© 2018, Pleiades Publishing, Ltd. Abstract: The reactions of solutions obtained by the reactions of Bi2O3 with 2 M HCl and HBr with the salts containing bis(pyridyl)alkane cations afford mono- and binuclear halide complexes (Py-(CH2)3-Py)3[Bi2Br9]2 (I), (H3O)(Py-(CH2)4-Py)[BiCl6] ⋅ 3H2O (II), and (H2Bpp)2[Bi2Br10] ⋅ 2H2O (Bpp is 1,3-bis(4-pyridyl)propane) (III). The structures of the synthesized compounds are determined by X-ray diffraction analysis (СIF files CCDC no. 1583338–1583340, respectively)

Development of a Series of Kynurenine 3-Monooxygenase Inhibitors Leading to a Clinical Candidate for the Treatment of Acute Pancreatitis

Recently, we reported a novel role for KMO in the pathogenesis of acute pancreatitis (AP). A number of inhibitors of kynurenine 3-monooxygenase (KMO) have previously been described as potential treatments for neurodegenerative conditions and particularly for Huntington’s disease. However, the inhibitors reported to date have insufficient aqueous solubility relative to their cellular potency to be compatible with the intravenous (iv) dosing route required in AP. We have identified and optimized a novel series of high affinity KMO inhibitors with favorable physicochemical properties. The leading example is exquisitely selective, has low clearance in two species, prevents lung and kidney damage in a rat model of acute pancreatitis, and is progressing into preclinical development

Functional and structural mimics of superoxide dismutase enzymes

Superoxide dismutase (SOD) enzymes form important defence line in living organisms. Through a dismutation reaction they transform the highly reactive superoxide radical ion to oxygen and hydrogen peroxide. The latter compound is further transformed by catalase or peroxidase enzymes to water and oxygen. The overall structure of the enzymes and those of the active sites are largely known, thus, it has been revealed that in eukaryotes Cu(II) and Zn(II) ions act as cofactors and they are connected with an imidazolate bridge and this structural unit is coordinated with amino acids. In prokaryotes the SOD enzymes contain Mn(II) or Fe(II) or Ni(II) in their active centres. In order to learn about the working mechanism of SOD enzymes at the molecular level various structural mimics were prepared and their structural transformations during the dismutation reaction was followed. Gathering adequate amount of information allowed the preparation of functional mimics that are not necessarily copies of the active sites of the enzymes, nevertheless, display considerable SOD activity. Both functional and structural mimics are comprehensively dealt with in this review. Although enzymes may seem to be attractive catalysts for promoting real-life reactions effectively with high selectivity, they can seldom if ever be used under industrial conditions, i.e. at high temperatures and pressures. The SOD enzymes for promoting oxygen transfer reactions are not durable enough under these conditions either. The complexes mimicking SOD activities perform better in this respect, however, their reusabilities are limited, because of separation problems. A solution can be the immobilisation of these SOD mimicking complexes on solid or semi-solid supports. Even if the activity is not better then the support-free complexes, the catalyst can be filtered at the end of the reaction and can easily be recycled. Attempts for immobilisation are also comprehensively reviewed and immobilised complexes with surprisingly high SOD activities are reported as well. Full characterisation of these materials is given and rationalisation of their exceptionally high activities is offered