Array Of Hydrogen Bonds Research Articles

An AAAA–DDDD quadruple hydrogen-bond array

Secondary electrostatic interactions between adjacent hydrogen bonds can have a significant effect on the stability of a supramolecular complex. In theory, the binding strength should be maximized if all the hydrogen-bond donors (D) are on one component and all the hydrogen-bond acceptors (A) are on the other. Here, we describe a readily accessible AAAA–DDDD quadruple hydrogen-bonding array that exhibits exceptionally strong binding for a small-molecule hydrogen-bonded complex in a range of different solvents (K(a) > 3 × 10(12) M(-1) in CH2Cl2, 1.5 × 10(6) M(-1) in CH3CN and 3.4 × 10(5) M(-1) in 10% v/v DMSO/CHCl3). The association constant in CH2Cl2 corresponds to a binding free energy (ΔG) in excess of –71 kJ mol(-1) (more than 20% of the thermodynamic stability of a carbon–carbon covalent bond), which is remarkable for a supramolecular complex held together by just four intercomponent hydrogen bonds.

Recognition characteristics of molecularly imprinted microspheres for triazine herbicides using hydrogen-bond array strategy and their analytical applications for corn and soil samples

The homogeneous molecularly imprinted microspheres (MIMs) based on a biologically inspired hydrogen-bond array were prepared using allobarbital as the novel functional monomer and divinylbenzene as the cross-linker. The host–guest binding characteristics were examined by molecular simulation and infrared spectroscopy. The resultant MIMs were evaluated using high performance liquid chromatography and solid-phase extraction. The results obtained demonstrate that the good imprinting effect and the excellent selectivity of MIMs are mainly due to the interaction involving the formation of three-point hydrogen bond between host and guest. The complete baseline separation was obtained for five triazine analogues and a metabolite on the MIM HPLC column. The MIMs were further successfully used as a specific sorbent for selective extraction of simetryne from corn and soil samples by molecularly imprinted solid phase extraction. Detection limits and recoveries were 5.8 μg/kg and 0.14 μg/kg and 87.4–105% and 94.6–101% for simetryne in corn and soil sample, respectively.

Hierarchical structures formed from self-complementary sextuple hydrogen-bonding arrays

A new self-complementary supramolecule based on U-DPy possesses an extremely high association constant, far exceeding those of existing systems (Kdimer > 107 M−1). In addition, its sextuple hydrogen bonding interaction and π-packing can be further promoted through annealing, resulting in a flat ribbon structure.

Substituent Control over Dimerization Affinity of Triply Hydrogen Bonded Heterodimers

Linear arrays of hydrogen bonds represent important elements of the supramolecular toolkit for receptor design, assembly of supramolecular polymers, and other well-defined supramolecular structures. It is illustrated that remote substituent effects control dimerization affinity in a predictable manner using a conformer independent ureidoimidazole DDA motif and its amidoisocytosine based AAD partner.

Crystal Structure and Local Dynamics in Tetrahedral Proton-Conducting La1-xBa1+xGaO4

La1-xBa1+xGaO4-δ (LBG) compounds, based on unconnected GaO4 moieties, were recently proposed as proton conductors. Protonic defects in the lattice are inserted through self-doping with Ba2+, to create oxygen vacancies subsequently filled by hydroxyl ions. We present a combined structural analysis on self-doped LBG using X-ray diffraction (XRD) and X-ray absorption (EXAFS): these results unravel the finer structural details on the short-range and long-range scales, and they are correlated with the dynamical properties of protonic conduction coming from vibrational spectroscopy. The structure of the GaO4 groups is independent of the oxide composition. On hydration, an array of short intertetrahedral hydrogen bonds is formed, producing a contraction of the a axis. On the basis of thermogravimetric analysis, EXAFS, XRD and infrared spectroscopy (IR) results, we propose that the stiffness of the GaO4 tetrahedra hinders the intratetrahedral proton transfer, while the noticeable fraction of protons involved in s...

Cover Picture: Proteomics 23'10

AbstractForks in the road to sobriety for outer membrane protein G (OmpG) under tensionMost work on protein unfolding and refolding has been done by shifting solution properties – pH, temperature, detergents, denaturants, salts, etc. Changing such bulk properties generally yields a simple two‐state model for renaturation – folded or unfolded. Unfolding by pulling at a single point on a tethered molecule with an atomic force microscope tip – single‐molecule force spectroscopy – allowed Damaghi et al. to map the forces required and the distances between the folded and unfolded states in much more detail. The OmpG molecule of E. coli is a barrel‐shaped transporter, comprising seven β‐hairpins. For hairpins I to IV the initial unfolding path steps are identical, then diverge as things become more complex, finally meeting again just before the last step. The rigidity of the pathways may be due in part to breaking up of an associated hydrogen bond array. An interesting benefit of the complexity is that it allows the separate evolution of the β‐loops for optimal function.Damaghi, M. et al., Proteomics 2010, 10, 4151–4162.Metering lights for the Translational Express?If you've driven on almost any urban American freeway (ha!) you have seen the signal lights that “meter” the traffic from the side roads onto the main highways. The genetic analogy is regulation of translational speed (red light time) through the choice of codons for multi‐codon amino acids. It has been observed that the faster codons appear more frequently in regions of mRNAs that tend to be susceptible to translational errors. The errors frequently take the form of protein aggregation. Lee et al. examined the effect quantitatively, looking at various types of amino acids, hidden and exposed, polar and hydrophobic, in five different organisms. There was no clear‐cut answer, but suggestions that it may be a way of reducing aggregation at functional sites by speeding up the translation rate to get past “sticky spots”.Lee, Y. et al., Proteomics 2010, 10, 4163–4171.A dictionary of ambiguities and singularitiesWe normally think of dictionaries as a source of truth, the ultimate arbiter of meaning and etymology. Now we face an ambiguous dictionary, one that lists only words up to six letters long but possibly with dozens of origins. Askenazi et al. have compiled a valuable reference that addresses a common problem for proteomics labs sequencing proteins from the bottom up: “How many different proteins could this peptide have come from?” They have built a service to answer the question. About every six months they aggregate ∼10 million protein sequences with their identifying information and connect the information to a rapid search software package (Pep2Pro). Test runs revealed that unique peptides can be found in a matter of seconds.Askenazi, M. et al., Proteomics 2010, 10, 4306–4310.

In this issue

AbstractForks in the road to sobriety for outer membrane protein G (OmpG) under tensionMost work on protein unfolding and refolding has been done by shifting solution properties – pH, temperature, detergents, denaturants, salts, etc. Changing such bulk properties generally yields a simple two‐state model for renaturation – folded or unfolded. Unfolding by pulling at a single point on a tethered molecule with an atomic force microscope tip – single‐molecule force spectroscopy – allowed Damaghi et al. to map the forces required and the distances between the folded and unfolded states in much more detail. The OmpG molecule of E. coli is a barrel‐shaped transporter, comprising seven β‐hairpins. For hairpins I to IV the initial unfolding path steps are identical, then diverge as things become more complex, finally meeting again just before the last step. The rigidity of the pathways may be due in part to breaking up of an associated hydrogen bond array. An interesting benefit of the complexity is that it allows the separate evolution of the β‐loops for optimal function.pp. 4151–4162Metering lights for the Translational Express?If you've driven on almost any urban American freeway (ha!) you have seen the signal lights that “meter” the traffic from the side roads onto the main highways. The genetic analogy is regulation of translational speed (red light time) through the choice of codons for multi‐codon amino acids. It has been observed that the faster codons appear more frequently in regions of mRNAs that tend to be susceptible to translational errors. The errors frequently take the form of protein aggregation. Lee et al. examined the effect quantitatively, looking at various types of amino acids, hidden and exposed, polar and hydrophobic, in five different organisms. There was no clear‐cut answer, but suggestions that it may be a way of reducing aggregation at functional sites by speeding up the translation rate to get past “sticky spots”.pp. 4163–4171A dictionary of ambiguities and singularitiesWe normally think of dictionaries as a source of truth, the ultimate arbiter of meaning and etymology. Now we face an ambiguous dictionary, one that lists only words up to six letters long but possibly with dozens of origins. Askenazi et al. have compiled a valuable reference that addresses a common problem for proteomics labs sequencing proteins from the bottom up: “How many different proteins could this peptide have come from?” They have built a service to answer the question. About every six months they aggregate ∼10 million protein sequences with their identifying information and connect the information to a rapid search software package (Pep2Pro). Test runs revealed that unique peptides can be found in a matter of seconds.pp. 4306–4310

Highly cooperative helix-sense reversal of polyaspartates. Influence of the comonomer of the opposite screw-sense preference

Poly( l-aspartic acid ester)s are known to form an α-helix in either the right(r)- or left(ℓ)-handed screw depending on the chemical constitution of the ester group in the side chain. While poly(β-benzyl l-aspartate) (PBLA) normally remains in the ℓ-form in conventional helicoidal solution at all temperatures, poly(β-phenethyl l-aspartate) (PPLA) exhibits transformation from the r- to ℓ-form with increasing temperature. In this work, random copolymers comprising residues of the two opposite screw-sense preferences, BLA and PLA, were chosen to investigate the stability of the α-helical hydrogen-bond array in a helix-forming solvent such as chloroform or 1,1,2,2-tetrachloroethane. Sharp S-shape transitions of the helix sense were observed for copolymers in the range PLA > 50%. The minor component BLA strictly obeys the majority rule in these copolymers. 2H NMR studies of partially deuterated samples in the nematic liquid-crystalline (LC) state have proved that the thermally induced r ↔ ℓ helix-sense inversion takes place highly cooperatively along the α-helical backbone: i.e., the cooperativity of the transition was not much affected by the inclusion of substantial amount of weaker points along the chain. These observations unambiguously suggest a zipper-type propagation process for PPLA starting from one terminal to the other. For given copolymer samples, the transition temperatures determined in dilute isotropic solution are nearly identical to those observed in the LC state, suggesting that the transition mechanism remains also similar. In the succeeding paper, relevant experimental data will be interpreted according to the theory consistent with these observations.

Unprecedented solid-state chemical reaction—from [formula omitted]. From centrosymmetric to non-centrosymmetric crystal structure

Tris(imidazolium) hexabromoantimonate(III) hydrate, ( C 3 N 2 H 5 ) 3 SbBr 6 · H 2 O , (abbreviated as TIBA) has been synthesized and characterized by X-ray (at 295, 225, 160, and 110 K), differential scanning calorimetry, dilatometry, and dielectric spectroscopy. At room temperature (phase I), the structure consists of discrete SbB 6 − anions, disordered imidazolium cations, and water molecules forming a 3D array of hydrogen bonds. Below room temperature, TIBA was found to undergo isostructural discontinuous phase transition at 212/221 K (cooling–heating) ( P 2 1 / c ↔ P 2 1 / c ) . The phase transition mechanism is characterized by two contributions: an order–disorder (cationic substructure) and a displacive (water molecules) one. At high temperatures, the TIBA crystal was found to undergo an unprecedented in situ solid-state chemical reaction: (1) 2 ( C 3 N 2 H 5 ) 3 SbBr 6 · H 2 O ( S ) → ( C 3 N 2 H 5 ) 5 Sb 2 Br 11 ( S ) + ( C 3 N 2 H 5 ) Br ( S ) + 2 H 2 O This chemical transformation leads to multiphase crystallites dominated by an amorphous phase of ( C 3 N 2 H 5 ) 5 Sb 2 Br 11 . The creation of ferroelectric crystallites – ( C 3 N 2 H 5 ) 5 Sb 2 Br 11 – in an “annealed” sample of ( C 3 N 2 H 5 ) 3 SbBr 6 · H 2 O was confirmed by X-ray diffraction phase analysis, dielectric spectroscopy, and pyroelectric measurements. The dielectric response of the electric permittivity and the critical slowing down of the process observed near 140 K in the “annealed” sample of TIBA are treated as a “fingerprint” of a neat ( C 3 N 2 H 5 ) 5 Sb 2 Br 11 ferroelectric.

RNA G-Quadruplexes in the model plant species Arabidopsis thaliana: prevalence and possible functional roles.

Tandem stretches of guanines can associate in hydrogen-bonded arrays to form G-quadruplexes, which are stabilized by K+ ions. Using computational methods, we searched for G-Quadruplex Sequence (GQS) patterns in the model plant species Arabidopsis thaliana. We found ∼1200 GQS with a G3 repeat sequence motif, most of which are located in the intergenic region. Using a Markov modeled genome, we determined that GQS are significantly underrepresented in the genome. Additionally, we found ∼43 000 GQS with a G2 repeat sequence motif; notably, 80% of these were located in genic regions, suggesting that these sequences may fold at the RNA level. Gene Ontology functional analysis revealed that GQS are overrepresented in genes encoding proteins of certain functional categories, including enzyme activity. Conversely, GQS are underrepresented in other categories of genes, notably those for non-coding RNAs such as tRNAs and rRNAs. We also find that genes that are differentially regulated by drought are significantly more likely to contain a GQS. CD-detected K+ titrations performed on representative RNAs verified formation of quadruplexes at physiological K+ concentrations. Overall, this study indicates that GQS are present at unique locations in Arabidopsis and that folding of RNA GQS may play important roles in regulating gene expression.

Understanding Hydrothermal Titanate Nanoribbon Formation

Titanate nanoribbons were prepared by hydrothermal treatment of neat TiO2 P25 with 10 M NaOH at 200 °C. Hydrothermal aging times were varied to assist with understanding the transformation process while the impact of postsynthesis acid washing on nanoribbon formation kinetics was assessed. Nanoribbon evolution was observed to occur via the formation of intermediate amorphous titanate particles. The final nanoribbon product was found to comprise a layered titanate framework with sodium cations interspersed between the sheets. Acid washing served to exchange the Na+ with H+ to give H2Ti3O7. Moreover, acid washing accelerated nanoribbon formation, providing a well-defined (i.e., no amorphous particles) nanoribbon sample after 15 h compared to 40 h when acid washing was not used. The difference in formation rates was attributed to interlayer formation of the intermediates in the hydrogen bond array (i.e., Ti−O−H) during H2Ti3O7 being faster than intermediate formation in the sodium bond array (i.e., Ti−O−Na)....

Eu3+-Assisted Short-Range Ordering of Photoluminescent Bridged Silsesquioxanes

The bridged silsesquioxane precursor (EtO)3Si(CH2)3NH(C═O)NH-(CH2)12-NH(C═O)NH(CH2)3 Si(OEt)3, combining polymerizable silylated groups, urea functionalities, and alkyl chains, undergoes fluoride (F−)-catalyzed sol−gel reactions in the presence or absence of EuCl3·6H2O. Supramolecular self-assembly of the growing structure relies primarily on the establishment of strong and ordered hydrogen bonding interactions. In the case of the Eu3+-containing hybrids the lanthanide ions play a totally unparallel dual-role acting simultaneously as structure directing agents and structural probes to sense locally morphological alterations. In the early stages of the synthesis, while a fraction of the Eu3+ ions promotes the formation of a unidirectional urea−urea hydrogen-bonded array, the remaining ions coordinate to silanol (Si−OH) groups inhibiting the growth of the siloxane network and yielding small anisotropic flakes (∼200 nm long). These are subsequently assembled on the micrometer scale in a brick-like tile-to-tile arrangement that ends up with the formation of fibers or twisted bundles (3.0−4.0 μm long and 0.5−1.0 μm wide). At higher Eu3+ concentrations, Eu3+-based ionic interfiber cross-links hinder the solvent flow and force adjacent fibers to adopt a bow-tie form (3.0−4.0 μm long and 3.0 μm wide at the tips). The hybrids are room temperature multiwavelength emitters because of the convolution of the hybrids’ intrinsic emission and the Eu3+ intra-4f6 transitions. The photoluminescence features (5D0→7F0 energy, 5D0 quantum efficiency, number of coordinated water molecules, and experimental intensity parameters) as a function of the Eu3+ content and acidic- and F−-catalyzed conditions used in the synthesis are compared to address the effect of the morphology in the photoluminescence features of the hybrid materials.

Hydrogen-bonded supramolecular motifs in pyrimethaminium 4-methylbenzoate, pyrimethaminium 3-hydroxypicolinate and pyrimethaminium 2,4-dichlorobenzoate

In 2,4-diamino-5-(4-chlorophenyl)-6-ethylpyrimidin-1-ium (pyrimethaminium, PMNH) 4-methylbenzoate, C(12)H(14)ClN(4)(+) x C(8)H(7)O(2)(-), (I), pyrimethaminium 3-hydroxypicolinate, C(12)H(14)ClN(4)(+) x C(6)H(4)NO(3)(-), (II), and pyrimethaminium 2,4-dichlorobenzoate, C(12)H(14)ClN(4)(+) x C(7)H(3)Cl(2)O(2)(-), (III), the PMNH cations interact with the carboxylate groups of the corresponding anion via nearly parallel N-H...O hydrogen bonds, forming R(2)(2)(8) ring motifs. A description of the observed arrays of quadruple hydrogen bonds in (I) and (II) in terms of hydrogen donors and acceptors (the DA model), their graph-set motifs and the resulting supramolecular ladder is given. In (III), supramolecular chains along the b axis and helical chains along the a axis are formed via N-H...O hydrogen bonds involving the 2-amino and 4-amino groups of the PMNH cation, respectively. Weak Cl...Cl interactions are also found in (III).

G‐Quadruplex Nucleic Acids

G-quadruplexes are a family of four-stranded structuresstabilized by guanine quartets, in which four planar guaninesestablish a cyclic array of hydrogen bonds. They are ofspecial interest due to the increasing evidence for theirformation in vivo and their possible implication in biology,especially at telomeres and as contributors to gene regulation.Moreover, G-quadruplexes are also formed as a result ofself-assembling processes of guanosine derivatives, yieldingseveral interesting motifs such as G-ribbons and G-wireswhich have peculiar electrical conductivity properties thatare being explored as molecular wires.This special issue is initiated with two articles discussingthe self-assembling properties of guanosine derivatives whichdescribe the basic principles of G-quadruplex formation. Thefirst article by Neviani et al. analyzes the presence of severallevels of organization of guanosine derivatives carryingone or two lipophilic units as observed by light scatteringtechniques and transmission electron microscopy (TEM)experiments. The second article by Mariani et al. describesa study on quadruplex formation of 2 -deoxyguanosinemonophosphate by small-angle X-ray scattering techniques.

Structure of an Odorant-Binding Protein from the Mosquito Aedes aegypti Suggests a Binding Pocket Covered by a pH-Sensitive “Lid”

BackgroundThe yellow fever mosquito, Aedes aegypti, is the primary vector for the viruses that cause yellow fever, mostly in tropical regions of Africa and in parts of South America, and human dengue, which infects 100 million people yearly in the tropics and subtropics. A better understanding of the structural biology of olfactory proteins may pave the way for the development of environmentally-friendly mosquito attractants and repellents, which may ultimately contribute to reduction of mosquito biting and disease transmission.MethodologyPreviously, we isolated and cloned a major, female-enriched odorant-binding protein (OBP) from the yellow fever mosquito, AaegOBP1, which was later inadvertently renamed AaegOBP39. We prepared recombinant samples of AaegOBP1 by using an expression system that allows proper formation of disulfide bridges and generates functional OBPs, which are indistinguishable from native OBPs. We crystallized AaegOBP1 and determined its three-dimensional structure at 1.85 Å resolution by molecular replacement based on the structure of the malaria mosquito OBP, AgamOBP1, the only mosquito OBP structure known to date.ConclusionThe structure of AaegOBP1 ( = AaegOBP39) shares the common fold of insect OBPs with six α-helices knitted by three disulfide bonds. A long molecule of polyethylene glycol (PEG) was built into the electron-density maps identified in a long tunnel formed by a crystallographic dimer of AaegOBP1. Circular dichroism analysis indicated that delipidated AaegOBP1 undergoes a pH-dependent conformational change, which may lead to release of odorant at low pH (as in the environment in the vicinity of odorant receptors). A C-terminal loop covers the binding cavity and this “lid” may be opened by disruption of an array of acid-labile hydrogen bonds thus explaining reduced or no binding affinity at low pH.

β-Cyclodextrin 10.41-hydrate

The crystal structure of β-cyclo­dextrin, C42H70O35·10.41H2O, consists of truncated cone-shaped β-cyclo­dextrin mol­ecules that are herringbone packed. The primary hydr­oxy groups form an intra­molecular hydrogen-bonded array. The semipolar cavity of the cyclo­dextrin host is filled with water mol­ecules, which show partial occupancy and disorder.

Theoretical and Experimental Studies of the Conversion of Chromopyrrolic Acid to an Antitumor Derivative by Cytochrome P450 StaP: The Catalytic Role of Water Molecules

Chromopyrrolic acid (CPA) oxidation by cytochrome P450 StaP is a key process in the biosynthesis of antitumor drugs (Onaka, H.; Taniguchi, S.; Igarashi, Y.; Furumai, T. Biosci. Biotechnol. Biochem. 2003, 67, 127-138), which proceeds by an unusual C-C bond coupling. Additionally, because CPA is immobilized by a hydrogen-bonding array, it is prohibited from undergoing direct reaction with Compound I, the active species of P450. As such, the mechanism of P450 StaP poses a puzzle. In the present Article, we resolve this puzzle by combination of theory, using QM/MM calculations, and experiment, using crystallography and reactivity studies. Theory shows that the hydrogen-bonding machinery of the pocket deprotonates the carboxylic acid groups of CPA, while the nearby His(250) residue and the crystal waters, Wat(644) and Wat(789), assist the doubly deprotonated CPA to transfer electron density to Compound I; hence, CPA is activated toward proton-coupled electron transfer that sets the entire mechanism in motion. The ensuing mechanism involves a step of C-C bond formation coupled to a second electron transfer, four proton-transfer and tautomerization steps, and four steps where Wat(644) and Wat(789) move about and mediate these events. Experiments with the dichlorinated substrate, CCA, which expels Wat(644), show that the enzyme loses its activity. H250A and H250F mutations of P450 StaP show that His(250) is important, but in its absence Wat(644) and Wat(789) form a hydrogen-bonding diad that mediates the transformation. Thus, the water diad emerges as the minimal requisite element that endows StaP with function. This highlights the role of water molecules as biological catalysts that transform a P450 to a peroxidase-type (Derat, E.; Shaik, S. J. Am. Chem. Soc. 2006, 128, 13940-13949).

Preparation, coordination properties and catalytic use of 1′-(diphenylphosphanyl)-1-ferrocenecarboxamides bearing 2-hydroxyethyl pendant groups

Abstract Polar amido-phosphane ligands, viz 1-(diphenylphosphanyl)-1′-[N-(2-hydroxyethyl)carbamoyl]ferrocene (1) and 1-(diphenylphosphanyl)-1′-[N,N-bis(2-hydroxyethyl)carbamoyl]ferrocene (2) were synthesised from 1′-(diphenylphosphanyl)-1-ferrocenecarboxylic acid (Hdpf) by direct amide coupling or via Hdpf-pentafluorophenyl ester 3. Subsequent reactions of 1 and 2 with [PdCl2(cod)] (cod = η2:η2-cyclocta-1,5-diene) gave the respective bis(phosphane) complexes trans-[PdCl2L2] (4, L = 1; 5, L = 2). Depending on the solvent used in their subsequent crystallisation (ethanol or chloroform), these complexes were isolated in several defined solvated forms. The structure determination for free ligands and their solvated complexes (4·2EtOH, 4·6CHCl3, 5·2EtOH, and 5·4CHCl3) revealed the dominating role of hydrogen bonding in their crystal assemblies, the nature and complexity of the formed hydrogen-bonded arrays strongly varying with the ligand structure (one vs. two 2-hydroxethyl chains), their number in the discrete species (free ligands vs. the complexes), and also with the solvate. Catalytic tests performed with 4 and 5 in Suzuki–Miyaura cross-coupling reaction showed that both complexes form active catalysts for the coupling of aryl bromides with phenylboronic acid in common polar organic solvents, in water and in toluene–water biphasic mixture. Yet, complex 4 gave rise to hydrolytically more stable catalyst, which could be used five times without any detectable loss of activity in the toluene/water system. Complex 4 was also successfully applied to the synthesis of biaryl anti-inflammatory drugs and their analogues in pure water and in the toluene–water mixture.

Bis(2,3-dimethylbutane-2,3-diamine)nickel(II) dinitrate monohydrate

In the title compound, [Ni(C6H16N2)2](NO3)2·H2O, the bis­(2,3-dimethyl­butane-2,3-diamine)nickel(II) complex cation possesses a relatively undistorted square-planar geometry about the Ni atom, which lies on an inversion centre and is coordinated by four N atoms from two symmetry-related 2,3-diamino-2,3-dimethyl­butane (tmen) ligands. The amine groups are N—H⋯O hydrogen bonded to the nitrate anions, which are, in turn, linked by inter­stitial water mol­ecules lying on a twofold axis. The infinite zigzag chains thus formed along [001] are further connected to each other by N—H⋯O hydrogen bonds towards the water mol­ecules, forming layers of two-dimensional hydrogen-bonded arrays.

(1-Butyl-1,4-diazabicyclo[2.2.2]octon-1-ium-κN4)trichloridocobalt(II)

The title compound, [Co(C10H21N2)Cl3], was obtained as the by-product of the attempted synthesis of a cobalt sulfate framework using 1,4-diaza­bicyclo­[2.2.2]octane as an organic template. The asymmetric unit comprises two distinct mol­ecules, and in each, the cobalt(II) ions are tetra­hedrally coordinated by three chloride anions and one 1-butyl­diaza­bicyclo­[2.2.2]octan-1-ium cation. The organic ligands are generated in situ, and exhibit two forms differentiated by the eclipsed and staggered conformations of the butyl groups. These mol­ecules inter­act by way of C—H⋯Cl hydrogen bonds, forming a three-dimensional hydrogen-bonding array.