Specific features of the structures of iron(II) α-benzyl dioxymate solvates with pyridine

Coordination compounds [Fe(DfgH)₂Py₂] (I) and [Fe(DfgH)₂Py₂] · A, where DfgH is the α-benzyldioxime monoanion and A = Py (II), DMF (III), and methyl ethyl ketone (IV), have been synthesized and studied by X-ray diffraction analysis. Diamagnetism and the gamma-resonance (GR) spectral parameters confirm that iron exists in the oxidation state +2 in the low-spin state. The octahedral trans configuration of the iron polyhedra is a common feature of all complexes. The equatorial plane of the octahedron contains two intramolecular hydrogen bonds O-H...O between two organic anions DfgH⁻ affording a pseudomacrocycle. The axial coordinate of the octahedron is occupied by the pyridine molecules, which are almost perpendicular to the equatorial plane N₄(oxime) in complexes I–IV. The structure of the compounds is a framework with allowance for weak interactions C-H...O and C-H...C. The manner of inclusion of solvents into the crystal and their functioning in structure formation of compounds II–IV are discussed.     

Electronic Structure of the Copper(II) Complex with Dimethyl Ether of 4-Phenylthiosemicarbazidediacetic Acid

The copper(II) coordination compound with dimethyl ether of 4-phenylthiosemicarbazidediacetic acid (Ef) was synthesized; its composition was [CuEfCl₂]. The quantum-chemical calculation of the electronic structure of the molecule was performed by the CNDO/2 method.     

Structure of aniline-containing Co(III) <Emphasis Type="Italic">trans</Emphasis>-dioximates with the [ZrF<Subscript>6</Subscript>]<Superscript>2−</Superscript> anion

Two new coordination compounds, trans-octahedral aniline-containing Co(III) dioximates [Co(DH)₂(Anil)₂]₂[ZrF₆]·2H₂O (I) and [Co(NioxH)₂(Anil)₂]₂[ZrF₆]·3H₂O (II), where DH^? is the dimethylglyoxime monoanion, and NioxH^? is the 1,2-cyclohexanedionedioxime monoanion, were synthesized, and their crystal structures were studied by XRD. In I, two centrosymmetric, crystallographically independent [Co(DH)₂(Anil)₂]⁺ complex cations (A and B) are linked by a system of hydrogen bonds, the [ZrF₆]^2? centrosymmetric anion, and the crystallization water molecules into a three-dimensional framework. The coordination polyhedron of the Co³⁺ atom in I and II is a slightly distorted N₆ octahedron formed by four nitrogen atoms of the two dioxime residues and two amine nitrogen atoms of the aniline fragment. The deviation of the cobalt atom from the plane of the metallocycle in II is up to 0.012 Å. The [ZrF₆]^2? outer-spheric anions and crystallization water molecules dominate in the crystal structures.     

Structure of sulfanilamide-containing cobalt(III) dioximates with the [ZrF<Subscript>6</Subscript>]<Superscript>2−</Superscript> and [BF<Subscript>4</Subscript>]<Superscript>−</Superscript> anions

The complexes [Co(DH)₂(Sam)₂]₂[ZrF₆]·5H₂O (I) and [Co(DH)₂(Sam)₂][BF₄]·H₂O (II), where DH^? is the dimethylglyoxime monoanion, and Sam is para-aminobenzenesulfamide (sulfanilamide, white streptocid), were synthesized, and their crystal structures were determined by X-ray diffraction analysis. The coordination polyhedron of the Co³⁺ atom is an N₆ octahedron formed by four nitrogen atoms of the two dimethylglyoxime residues and two nitrogen atoms of the Sam fragments. The latter are realized in virtually parallel orientation relative to the polyhedron of the metal atom and its equatorial plane; the average value of the dihedral angles is 26.8(1)°, and there is π-π interaction between the benzene rings of the Sam fragments and the π delocalized equatorial metallocycle. The deviation of the cobalt atom from the four-angle plane is up to 0.009(1) Å. The (Co-N)_DH? and (Co-N)_Sam distances in the [Co(DH)₂(Sam)₂]⁺ complex cations vary from 1.892(2) Å to 1.907(3) Å and from 2.000(2) Å to 2.012(2) Å, respectively. The [ZrF₆]^2? and [BF₄]^? complex anions play the major role in crystal formation; they produce a substantial effect on the formation of a complex system of hydrogen bonds.     

Lead-like, drug-like or “Pub-like”: how different are they?

Academic and industrial research continues to be focused on discovering new classes of compounds based on HTS. Post-HTS analyses need to prioritize compounds that are progressed to chemical probe or lead status. We report trends in probe, lead and drug discovery by examining the following categories of compounds: 385 leads and the 541 drugs that emerged from them; "active" (152) and "inactive" (1488) compounds from the Molecular Libraries Initiative Small Molecule Repository (MLSMR) tested by HTS; "active" (46) and "inactive" (72) compounds from Nature Chemical Biology (NCB) tested by HTS; compounds in the drug development phase (I, II, III and launched), as indexed in MDDR; and medicinal chemistry compounds from WOMBAT, separated into high-activity (5,784 compounds with nanomolar activity or better) and low-activity (30,690 with micromolar activity or less). We examined Molecular weight (MW), molecular complexity, flexibility, the number of hydrogen bond donors and acceptors, LogP-the octanol/water partition coefficient estimated by ClogP and ALOGPS), LogSw (intrinsic water solubility, estimated by ALOGPS) and the number of Rule of five (Ro5) criteria violations. Based on the 50% and 90% distribution moments of the above properties, there were no significant difference between leads of known drugs and "actives" from MLSMR or NCB (chemical probes). "Inactives" from NCB and MLSMR were also found to exhibit similar properties. From these combined sets, we conclude that "Actives" (569 compounds) are less complex, less flexible, and more soluble than drugs (1,651 drugs), and significantly smaller, less complex, less hydrophobic and more soluble than the 5,784 high-activity WOMBAT compounds. These trends indicate that chemical probes are similar to leads with respect to some properties, e.g., complexity, solubility, and hydrophobicity.     

Synthesis and crystal structure of Co(III) dioximates with the complex anion [SbF6]?

The complexes [Co(DioxH)₂L₂][SbF₆] · nH₂O, where DioxH is dimethylglyoxime monoanion (DioxH^?) or 1,2-cyclohexanedione dioxime (NioxH^?), L is aniline (An) or triphenylphosphine (PPh₃), were isolated from the CoX₂ · nH₂O-NaSbF₆-DioxH₂-L system (X = F or CH₃COO) in aqueous methanol. The complexes were studied by UV, IR, and NMR spectroscopy and by X-ray diffraction. The crystal structure of [Co(DH)₂(An)₂][SbF₆] · H₂O (I) and [Co(NioxH)₂(PPh₃)₂][SbF₆] (II) is stabilized by the electrostatic interactions between the Co(III) complex cations and outer-sphere fluorine-containing anions and by hydrogen bonds between structural units.     

Cobalt(III) azide dimethylglyoximates with some sulfanilamide derivatives: Synthesis and crystal structures

A number of new Co(III) dimethylglyoximates containing N-pyrimidinylsulfanilamides were obtained. These complexes of the general formula [Co(N₃)(DH)₂L] (I?CV) (where DH is the dimethylglyoxime monoanion and L are N-pyrimidinylsulfanilamides NH₂-C₆H₄-SO₂-NH-R with different substituents R) are expected to have antibacterial properties. Their structures were examined by IR, electronic absorption, and NMR spectroscopy and X-ray diffraction. They were classified among cobalt(III) trans dioximates. In all the complexes obtained, the cobalt atom coordinates to four N atoms of two dimethylglyoxime residues. The octahedral environment of the metal atom is completed with the amino N atom of the neutral molecule L and the N atom of the azide anion. In the crystal structures, complexes I?CV are united through intermolecular hydrogen bonds N-H??O, N-H??N, and O-H??O, in which the groups ?NH₂ and =NH of the ligand L and water molecules (for I, IV, and V) serve as proton donors.     

Of possible cheminformatics futures

For over a decade, cheminformatics has contributed to a wide array of scientific tasks from analytical chemistry and biochemistry to pharmacology and drug discovery; and although its contributions to decision making are recognized, the challenge is how it would contribute to faster development of novel, better products. Here we address the future of cheminformatics with primary focus on innovation. Cheminformatics developers often need to choose between “mainstream” (i.e., accepted, expected) and novel, leading-edge tools, with an increasing trend for open science. Possible futures for cheminformatics include the worst case scenario (lack of funding, no creative usage), as well as the best case scenario (complete integration, from systems biology to virtual physiology). As “-omics” technologies advance, and computer hardware improves, compounds will no longer be profiled at the molecular level, but also in terms of genetic and clinical effects. Among potentially novel tools, we anticipate machine learning models based on free text processing, an increased performance in environmental cheminformatics, significant decision-making support, as well as the emergence of robot scientists conducting automated drug discovery research. Furthermore, cheminformatics is anticipated to expand the frontiers of knowledge and evolve in an open-ended, extensible manner, allowing us to explore multiple research scenarios in order to avoid epistemological “local information minimum trap”.     

Untersuchungen über die Aufnahme von Nitratstickstoff durch Hafer mit Hilfe von 15N

Die Aufnahme von Nitratstickstoff durch Hafer wurde in Gegenwart von Ammoniumstickstoffüberschuß sowie verschiedener Stickstoffdügermichungen untersucht. Ebenfalls wurde der Einfluß phosphor-, kalium-, und spurenelementhaliger Düngemittel auf den Ausmutzungskoeffizienten des Nitratstickstoffs durch Hafer geprüft. Der Nitratstickstoff des angewandten Ammonium- nitrats wurde mit dent stabilen Stickstoffisotop ¹⁵N markiert. Die Masse der trockenen Planzen, der Gesamtstickstoffgehalt und der Ausnutzungskoeffizient des Nitratstickstoffs durch die Planzen wurden bestimut. Die Versuche haben gezeigt, daß der Ausmutzungskoeffizient des Nitratstickstoffs durch die Pfanzen in Geganwart con Ammoniumstickstoffüberschuß nicht wesentlich beeinflußt wird.