Poly[(N,N‐dimethylformamide‐κO)(μ3‐4,4′‐ethylenedibenzoato‐κ5O,O′:O′:O′′,O′′′)(pyrazino[2,3‐f][1,10]phenanthroline‐κ2N8,N9)lead(II)]

In the title Pb^II coordination polymer, [Pb(C₁₆H₁₀O₄)(C₁₄H₈N₄)(C₃H₇NO)]_n, each Pb^II atom is eight‐coordinated by two chelating N atoms from one pyrazino[2,3‐f][1,10]phenanthroline (L) ligand, one dimethylformamide (DMF) O atom and five carboxylate O atoms from three different 4,4′‐ethylenedibenzoate (eedb) ligands. The eedb dianions bridge neighbouring Pb^II centres through four typical Pb—O bonds and one longer Pb—O interaction to form a two‐dimensional structure. The C atoms from the L and eedb ligands form C—H...O hydrogen bonds with the O atoms of eedb and DMF ligands, which further stabilize the structure. The title compound is the first Pb^II coordination polymer incorporating the L ligand.     

catena‐Poly[[[triaquazinc(II)]‐μ‐2‐nitroterephthalato‐κO1:κ2O4,O4′] monohydrate]

The title complex, {[Zn(C₈H₃NO₆)(H₂O)₃]·H₂O}_n, has a one‐dimensional chain structure. The two carboxylate groups of the dianionic 2‐nitroterephthalate ligand adopt mono‐ and bidentate chelating modes. The Zn atom shows distorted octahedral coordination, bonded to three O atoms from two carboxylate groups and three O atoms of three non‐equivalent coordinated water molecules. The one‐dimensional chains are aggregated into two‐dimensional layers through inter‐chain hydrogen bonding. The whole three‐dimensional structure is further stabilized by inter‐layer hydrogen bonds.     

trans‐Di­aqua­bis(6‐hydroxy­picolinato‐κ2N,O2)copper(II)

In the title compound, [Cu(C₆H₄NO₃)₂(H₂O)₂], the Cu^II ion lies on an inversion centre and has an elongated octahedral environment, equatorially trans‐coordinated by two N,O‐bidentate picolinate ligands and axially coordinated by two water O atoms. The complex mol­ecules form layers, which are linked by O—H⋯O hydrogen bonds between the aqua ligands and neighbouring carboxyl­ate groups. An intramolecular hydrogen bond between the coordinated carboxyl­ate O atom and the hydroxy H atom is also observed.     

Poly[[triaquazinc(II)]‐μ3‐4‐nitrophthalato‐κ3O1:O2:O2′]

In the title complex, [Zn(C₈H₃NO₆)(H₂O)₃]_n, the two carboxylate groups of the 4‐nitrophthalate dianion ligands have monodentate and 1,3‐bridging modes, and Zn atoms are interconnected by three O atoms from the two carboxylate groups into a zigzag one‐dimensional chain along the b‐axis direction. The Zn atom shows distorted octahedral coordination as it is bonded to three O atoms from carboxylate groups of three 4‐nitrophthalate ligands and to three O atoms of three non‐equivalent coordinated water molecules. The one‐dimensional chains are aggregated into two‐dimensional layers through inter‐chain hydrogen bonding. The whole three‐dimensional structure is further maintained and stabilized by inter‐layer hydrogen bonds.     

Tetrakis(μ2‐4‐aminobenzoato)di‐μ3‐oxido‐tetrakis[dibutyltin(IV)]

The molecule of the title compound, [Sn₄(C₄H₉)₈(C₇H₆NO₂)₄O₂], lies about an inversion centre and is a tetranuclear bis(tetrabutyldicarboxylatodistannoxane) complex containing a planar Sn₄O₂ core in which two μ₃‐oxide O atoms connect an Sn₂O₂ ring to two exocyclic Sn atoms. Each Sn atom has a highly distorted octahedral coordination. In the molecule, the carboxylate groups of two aminobenzoate ligands bridge the central and exocyclic Sn atoms, while two further aminobenzoate ligands have highly asymmetric bidentate chelation to the exocyclic Sn atoms plus long O...Sn interactions with the central Sn atoms. Each Sn atom is also coordinated by two pendant n‐butyl ligands, which extend roughly perpendicular to the plane of the Sn₄O₁₀ core. Only one of the four unique hydrogen‐bond donor sites is involved in a classic N—H...O hydrogen bond, and the resulting supramolecular hydrogen‐bonded structure is an extended two‐dimensional network which lies parallel to the (100) plane and consists of a checkerboard pattern of four‐connected molecular cores acting as nodes. The amine groups not involved in the hydrogen‐bonding interactions have significant N—H...π interactions with neighbouring aminobenzene rings.     

The new three‐dimensional supramolecule bis{μ‐2‐[(4‐hydroxybenzoyl)hydrazonomethyl]phenolato}bis[aquacopper(II)] dinitrate

In the title centrosymmetric binuclear complex, [Cu₂(C₁₄H₁₁N₂O₃)₂(H₂O)₂](NO₃)₂, the two metal centres are bridged by the phenolate O atoms of the ligand, forming a Cu₂O₂ quadrangle. Each Cu atom has a distorted square‐pyramidal geometry, with the basal donor atoms coming from the O,N,O′‐tridentate ligand and a symmetry‐related phenolate O atom. The more weakly bound apical donor O atom is supplied by a coordinated water molecule. When a further weak Cu...O interaction with the 4‐hydroxy O atom of a neighbouring cation is considered, the extended coordination sphere of the Cu atom can be described as distorted octahedral. This interaction leads to two‐dimensional layers, which extend parallel to the (100) direction. The two‐dimensional polymeric structure contrasts with other reported structures involving salicylaldehyde benzoylhydrazone ligands, which are usually discrete mono‐ or dinuclear Cu complexes. The nitrate anions are involved in a three‐dimensional hydrogen‐bonding network, featuring intermolecular N—H...O and O—H...O hydrogen bonds.     

trans‐Bis(diethanolamine‐N,O)bis(saccharinato‐N)cadmium(II)

The structure of the title complex consists of isolated [Cd(C₇H₄NO₃S)₂(C₄H₁₁NO₂)₂] units. The Cd²⁺ cation lies on an inversion centre and is octahedrally coordinated by two N,O‐bidentate diethanol­amine (dea) and two N‐bonded saccharinate (sac) ligands [saccharin is 1,2‐benziso­thia­zol‐3(2H)‐one 1,1‐dioxide]. The dea ligands constitute the equatorial plane of the octahedron, forming two five‐membered chelate rings around the Cd^II ion, while the sac ligands are localized at the axial positions. The Cd—N_sac, Cd—N_dea and Cd—O_dea bond distances are 2.3879 (12), 2.3544 (14) and 2.3702 (13) Å, respectively. The H atoms of the free and coordinated hydroxyl groups of the dea ligands are involved in hydrogen bonding with the carbonyl and sulfonyl O atoms of the neighbouring sac ions, while the amine H atom forms a hydrogen bond with the free hydroxyl O atom. The individual mol­ecules are held together by strong hydrogen bonds, forming an infinite three‐dimensional network.     

Ethyl 3‐[1‐(5,5‐dimethyl‐2‐oxo‐1,3,2‐dioxaphosphorin‐2‐yl)propan‐2‐ylidene]carbazate: a combined X‐ray and density functional theory (DFT) study

In the title compound, C₁₁H₂₁N₂O₅P, one of the two carbazate N atoms is involved in the C=N double bond and the H atom of the second N atom is engaged in an intramolecular hydrogen bond with an O atom from the dimethylphosphorin‐2‐yl group, which is in an uncommon cis position with respect to the carbamate group. The cohesion of the crystal structure is also reinforced by weak intermolecular hydrogen bonds. Density functional theory (DFT) calculations at the B3LYP/6‐311++g(2d,2p) level revealed the lowest energy structure to have a Z configuration at the C=N bond, which is consistent with the configuration found in the X‐ray crystal structure, as well as a less stable E counterpart which lies 2.0 kcal mol⁻¹ higher in potential energy. Correlations between the experimental and computational studies are discussed.     

Helical catena‐poly[[tris(1H‐benzimidazole‐κN3)cobalt(II)]‐μ‐maleato‐κ3O,O′:O′′]

The crystal structure of the title compound, [Co(C₄H₂O₄)(C₇H₆N₂)₃]_n, consists of polymeric chains of the Co^II complex. Two maleate dianions and three benz­imidazole ligands coordinate to the Co^II atom with a distorted octahedral geometry. The maleate dianions bridge neighbouring Co^II atoms via both terminal carboxylic acid groups, one of which is monodentate and the other bidentate, to form a helical structure of alternating maleate dianions and Co^II atoms, with a pitch height of 9.2667 (17) Å. The absolute structure has been determined, and the crystal contains only right‐handed helices. Intrahelical N—H⋯O hydrogen bonds stabilize the helical structure, while interhelical N—H⋯O hydrogen bonds link neighbouring helices to form the supramolecular structure.     

Mercury(II) thiolate complexes of two flexible benzimidazole‐based ligands

The structure of catena‐poly[[{bis[4‐(trimethylammonio)benzenethiolate‐κS]mercury(II)}‐μ‐1,1′‐(ethane‐1,2‐diyl)bis(1H‐benzimidazole)‐κ²N³:N^3′] bis(hexafluoridophosphate) 0.25‐hydrate], {[Hg(C₁₆H₁₄N₄)(C₉H₁₃NS)₂](PF₆)₂·0.25H₂O}_n, contains a one‐dimensional zigzag chain. The Hg^II cation is coordinated by two S atoms of two 4‐(trimethylammonio)benzenethiolate (Tab) ligands and by two N atoms from two different 1,1′‐(ethane‐1,2‐diyl)bis(1H‐benzimidazole) ligands, forming a distorted seesaw‐shaped coordination geometry. The F atoms of the hexafluoridophosphate anion interact with the H atoms of the Tab ligand, generating a two‐dimensional network. Furthermore, this layer is connected to neighbouring layers via H...π interactions, thereby forming a three‐dimensional hydrogen‐bonded structure. In catena‐poly[[{[4‐(trimethylammonio)benzenethiolate‐κS]mercury(II)}bis[μ‐4‐(trimethylammonio)benzenethiolate‐κ²S:S]{[4‐(trimethylammonio)benzenethiolate‐κS]mercury(II)}‐μ‐1,1′‐(hexane‐1,6‐diyl)bis(1H‐benzimidazole)‐κ²N³:N^3′] tetrakis(hexafluoridophosphate)], {[Hg₂(C₂₀H₂₂N₄)(C₉H₁₃NS)₄](PF₆)₄}_n, each Hg^II cation is coordinated by two S atoms of two Tab ligands and one N atom of the 1,1′‐(hexane‐1,6‐diyl)bis(1H‐benzimidazole) (hbbm) ligand, forming a distorted T‐shaped coordination geometry, while longer secondary Hg...S bonds join two such units across a centre of inversion to give the tetravalent cation. Adjacent {[Hg(Tab)₂]₂(μ‐hbbm)}⁴⁺ cations are linked through the centrosymmetric hbbm ligands to afford a one‐dimensional chain extending along the b axis. Several F atoms interact with the H atoms of the Tab and hbbm ligands, while the S atom interacts with an aromatic H atom of a different Tab ligand, to afford a complex intra‐ and intermolecular hydrogen‐bonding arrangement in a three‐dimensional structure.     

cis‐Dichloridobis(1,10‐phenanthroline‐5,6‐diol‐κ2N,N′)manganese(II): a supramolecular chain formed via O—H...Cl bonds and aromatic stacking

The title compound, [MnCl₂(C₁₂H₈N₂O₂)₂], displays a novel supramolecular chain formed by intermolecular O—H...Cl hydrogen bonds and aromatic stacking. The molecule has crystallographically imposed twofold symmetry with the Mn^II atom on the twofold axis. In the 1,10‐phenanthroline‐5,6‐diol ligand, each H atom of the two hydroxy groups is oriented towards the other hydroxy O atom. Both hydroxy groups form intermolecular O—H...Cl hydrogen bonds with a single Cl atom of an adjacent molecule. These hydrogen bonds connect the molecules via operation of the molecular twofold axis and the centre of inversion of the crystal lattice, forming a doubly‐bridged one‐dimensional structure with Mn atoms as the nodes. Strong aromatic π‐stacking between two antiparallel neighbouring 1,10‐phenanthroline‐5,6‐diol ligands also helps to stabilize the chain.     

catena‐Poly­[[bis­(thio­cyanato‐N)lead(II)]‐μ‐1,2‐bis(4‐pyridyl)ethane‐N:N′]

In the title coordination polymer, [Pb(NCS)₂(C₁₂H₁₂N₂)], the coordination geometry about the Pb^II atom is a distorted octahedron, composed of two N atoms from bpe ligands [bpe is 1,2‐bis(4‐pyridyl)ethane], two other N atoms from NCS^? groups and two neighbouring S atoms through short contacts. The trans‐bpe ligands act as bridges between two Pb^II centres resulting in the formation of a linear chain. The terminal S atoms of the NCS^? ligands make short contacts with the Pb^II atom of neighbouring chains to form an infinite two‐dimensional polymeric structure.     

Structure and thermal decomposition of poly[[triaqua(μ4‐oxydiacetato)lanthanum(III)] nitrate]

In the title lanthanum complex, {[La(C₄H₄O₅)(H₂O)₃]NO₃}_n, the lanthanum cation is immersed in a nine‐coordinate environment provided by a tridentate oxydiacetate (oda) ligand (through two carboxylate and one ether O atoms), three carboxylate O atoms from neighbouring oda ligands and three aqua ligands. The LaO₉ polyhedra are interlinked into a tight three‐dimensional framework, which leaves holes where the nitrate anions lodge. The links to the polymeric framework are by an extensive hydrogen‐bonding scheme utilizing all the water H atoms. Thermogravimetric analysis shows that the three coordinated water molecules leave the structure in two well differentiated steps.     

Cocrystals of the antibiotic trimethoprim with glutarimide and 3,3‐dimethylglutarimide held together by three hydrogen bonds

The antibiotic trimethoprim [5‐(3,4,5‐trimethoxybenzyl)pyrimidine‐2,4‐diamine] was cocrystallized with glutarimide (piperidine‐2,6‐dione) and its 3,3‐dimethyl derivative (4,4‐dimethylpiperidine‐2,6‐dione). The cocrystals, viz. trimethoprim–glutarimide (1/1), C₁₄H₁₈N₄O₃·C₅H₇NO₂, (I), and trimethoprim–3,3‐dimethylglutarimide (1/1), C₁₄H₁₈N₄O₃·C₇H₁₁NO₂, (II), are held together by three neighbouring hydrogen bonds (one central N—H...N and two N—H...O) between the pyrimidine ring of trimethoprim and the imide group of glutarimide, with an ADA/DAD pattern (A = acceptor and D = donor). These heterodimers resemble two known cocrystals of trimethoprim with barbituric acid and its 5,5‐diethyl derivative. Trimethoprim shows a conformation in which the planes of the pyrimidine and benzene rings are approximately perpendicular to one another. In its glutarimide coformer, five of the six ring atoms lie in a common plane; the C atom opposite the N atom deviates by about 0.6 Å. The crystal packing of each of the two cocrystals is characterized by an extended network of hydrogen bonds and contains centrosymmetrically related trimethoprim homodimers formed by a pair of N—H...N hydrogen bonds. This structural motif occurs in five of the nine published crystal structures in which neutral trimethoprim is present.     

7‐Cyclopropyl‐2′‐deoxytubercidin: a carbocyclic side‐chain derivative of 7‐deaza‐2′‐deoxyadenosine

The title compound {systematic name: 4‐amino‐5‐cyclopropyl‐7‐(2‐deoxy‐β‐D‐erythro‐pentofuranosyl)‐7H‐pyrrolo[2,3‐d]pyrimidine}, C₁₄H₁₈N₄O₃, exhibits an anti glycosylic bond conformation, with the torsion angle χ = −108.7 (2)°. The furanose group shows a twisted C1′‐exo sugar pucker (S‐type), with P = 120.0 (2)° and τ_m = 40.4 (1)°. The orientation of the exocyclic C4′—C5′ bond is ‐ap (trans), with the torsion angle γ = −167.1 (2)°. The cyclopropyl substituent points away from the nucleobase (anti orientation). Within the three‐dimensional extended crystal structure, the individual molecules are stacked and arranged into layers, which are highly ordered and stabilized by hydrogen bonding. The O atom of the exocyclic 5′‐hydroxy group of the sugar residue acts as an acceptor, forming a bifurcated hydrogen bond to the amino groups of two different neighbouring molecules. By this means, four neighbouring molecules form a rhomboidal arrangement of two bifurcated hydrogen bonds involving two amino groups and two O5′ atoms of the sugar residues.     

Ab initio study of C4H3 potential energy surface and reaction of ground‐state carbon atom with propargyl radical

The potential energy surface for the reaction of the ground‐state carbon atom [C(³P_j)] with the propargyl radical [HCCCH₂(X²B₁)] is investigated using the G2M(RCC,MP2) method. Numerous local minima and transition states for various isomerization and dissociation pathways of doublet C₄H₃ are studied. The results show that C(³P_j) attacks the π system of the propargyl radical at the acetylenic carbon atom and yields the n‐C₄H₃(²A′) isomer i3 after an 1,2‐H atom shift. This intermediate either splits a hydrogen atom and produces singlet diacetylene, [HCCCCH ( p1 )+H] or undergoes (to a minor amount) a 1,2‐H migration to i‐C₄H₃(²A′) i5 , which in turn dissociates to p1 plus an H atom. Alternatively, atomic carbon adds to the triple C?C bond of the propargyl radical to form a three‐member ring C₄H₃ isomer i1 , which ring opens to i3 . Diacetylene is concluded to be a nearly exclusive product of the C(³P_j)+HCCCH₂ reaction. At the internal energy of 10.0 kcal/mol above the reactant level, Rice–Ramsperger–Kassel–Marcus calculations show about 91.7% of HCCCCH comes from fragmentation of i3 and 8.3% from i5 . The other possible minor channels are identified as HCCCC+H₂ and C₂H+HCCH. © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 1522–1535, 2001     

2,2‐Di­methyl‐1‐(2,4,6‐tri­nitro­phenyl)­hydrazine

The title mol­ecule (DMPH‐H), C₈H₉N₅O₆, was investigated to provide comparison with 2,2‐di­phenyl‐1‐picryl­hydrazine, which unlike DMPH‐H is readily oxidizable to form a well known stable free radical (DPPH). The structure shows essential differences in the configuration of the hydrazine‐N atoms, the ortho‐nitro group orientations and the crystal packing. The bond angles of the di­methyl­amino N atom [107.90 (13), 108.96 (12) and 112.21 (13)°] are consistent with a tetrahedral N atom and sp³ hybridization.     

Bis(5‐aminotetrazole‐1‐acetato‐κO)tetraaquacobalt(II) and catena‐poly[[cadmium(II)]‐bis(μ‐5‐aminotetrazole‐1‐acetato‐κ3N4:O,O′)]

The Co^II atom in bis(5‐aminotetrazole‐1‐acetato)tetraaquacobalt(II), [Co(C₃H₄N₅O₂)₂(H₂O)₄], (I), is octahedrally coordinated by six O atoms from two 5‐aminotetrazole‐1‐acetate (atza) ligands and four water molecules. The molecule has a crystallographic centre of symmetry located at the Co^II atom. The molecules of (I) are interlinked by hydrogen‐bond interactions, forming a two‐dimensional supramolecular network structure in the ac plane. The Cd^II atom in catena‐poly[[cadmium(II)]‐bis(μ‐5‐aminotetrazole‐1‐acetato], [Cd(C₃H₄N₅O₂)₂]_n, (II), lies on a twofold axis and is coordinated by two N atoms and four O atoms from four atza ligands to form a distorted octahedral coordination environment. The Cd^II centres are connected through tridentate atza bridging ligands to form a two‐dimensional layered structure extending along the ab plane, which is further linked into a three‐dimensional structure through hydrogen‐bond interactions.     

catena‐Poly[copper(II)‐di‐μ‐acetylacetonato‐copper(II)‐bis(μ‐4‐hydroxy‐3‐methoxybenzaldehyde picoloylhydrazonato)] and (acetylacetonato)(4‐methoxybenzaldehyde picoloylhydrazonato)copper(II)

In the two title copper(II) complexes, [CuL(C₅H₇O₂)]_n, (I), and [CuL′(C₅H₇O₂)], (II), respectively, where HL is 4‐hydroxy‐3‐methoxybenzaldehyde picoloylhydrazone, C₁₄H₁₂N₃O₃, and HL′ is 4‐methoxybenzaldehyde picoloylhydrazone, C₁₄H₁₂N₃O₂, the Cu^II ions display a highly Jahn–Teller‐distorted octahedral and a square‐planar coordination geometry, respectively. In complex (I), two neighbouring Cu^II atoms are bridged by L⁻ and acetylacetonate, alternately, giving rise to a one‐dimensional chain of CuN₂O₄ octahedra interconnected by these two ligands along the a axis. In addition, the hydroxy H atom of the vanillin group connects to the carboxyl O atom of the adjacent chain via an O—H...O hydrogen bond, giving rise to a three‐dimensional supramolecular assembly. Complex (II) displays a discrete structure.     

2‐[6‐(1H‐Benzimidazol‐2‐yl)‐2‐pyridyl]‐1H‐benzimidazol‐3‐ium perchlorate monohydrate

The title compound, C₁₉H₁₄N₅⁺·ClO₄^?·H₂O, contains planar C₁₉H₁₄N₅⁺ cations, perchlorate anions and water mol­ecules. The two closest parallel cations (plane‐to‐plane distance of 3.41 Å), together with two neighbouring perchlorate anions and two water mol­ecules, form an electrically neutral quasi‐dimeric unit. Two acidic H atoms of the cation, both H atoms of the water mol­ecule, the N atoms of the imidazole rings and three of the four O atoms of the perchlorate anion are involved in the hydrogen‐bonding network within the dimeric unit. The remaining third acidic H atom of the imidazole rings and the water mol­ecules complete a two‐dimensional network of hydrogen bonds, thus forming puckered layers of dimers. The angle between the planes of two neighbouring dimeric units in the same layer is 33.25 (3)°.