Polymeric Arrangement Research Articles

Coordination properties of diethyl (pyridin-2-ylmethyl)phosphate (2-pmOpe) ligand with perchlorate transition metal salts: Crystal structure of [Co(2-pmOpe) 2(H 2O) 2](ClO 4) 2

A new series of the perchlorate transition-metal complexes containing the diethyl (pyridin-2-ylmethyl)phosphate (2-pmOpe) ligand of general formula [M(2-pmOpe) 2(H 2O) 2](ClO 4) 2 (M = Cu, Ni, Co) were prepared. The complexes were identified and characterized by elemental analysis, spectroscopic and magnetic studies. The ligand containing two donor atoms, heterocyclic pyridyl nitrogen and phosphoryl oxygen atoms, binds in a bidentate chelate manner in all complexes. The crystal structure for [Co(2-pmOpe) 2(H 2O) 2](ClO 4) 2 was determined by the X-ray diffraction method. The geometry of CoN 2O 4 chromophore shows an elongated octahedron, resulting from the bidentate N,O-bonded two chelate ligands and two coordinated water molecules. Every mononuclear unit is linked to other ones via two extended Co O H⋯O Cl O⋯H O Co bridges, forming one-dimensional (1D) hydrogen bond system. Additionally, weak C H⋯O and π–π interactions link the chains resulting in a three-dimensional (3D) (supramolecular architecture) polymeric network arrangement. Spectroscopic and magnetic results are presented in the light of the crystal structure. Magnetic data of mononuclear Co(II) compound indicate an influence of a large zero-field splitting (ZFS) and very weak intermolecular exchange interaction ( zJ ’ = −0.48 cm −1) on magnetic behavior. The spectroscopic and magnetic properties of Cu(II) and Ni(II) complexes indicate octahedral and mononuclear structure of both compounds.

Poly[bis(μ2-formato-κ2O:O′)(quinoxaline-κN)copper(II)

In the polymeric title copper(II) compound, [Cu(CHO2)2(C8H6N2)]n, both formato ligands are O-bidentate anions and act as bridging ligands, creating a planar polymeric arrangement. The slightly distorted square-pyramidal coordination around CuII comprises four O atoms from two different formate anions as the base and a quinoxaline mol­ecule in the apical position.

Structure Determination of Unsolvated Potassium, Rubidium, and Cesium Carbazolates

The solid-state structures of unsolvated potassium, rubidium, and cesium carbazolates were determined using laboratory X-ray powder diffraction data. Potassium and rubidium carbazolates adopt a polymeric helical arrangement, whereas cesium carbazolate forms a polymeric twisted column structure.

Synthesis, Crystal Structure and Supramolecular Organization of the 1D Coordination Polymer [Cu(HCOO)2(4‐bpytm)], (4‐bpytm = Bis(4‐pyridylthio)methane)

AbstractThe reaction of the flexible pyridyl dithioether ligand Bis(4‐pyridylthio)methane (4‐bpytm) with copper(II) formiate led to the formation of the coordination polymer [Cu(HCOO)2(4‐bpytm)]n, which has been characterized structurally. The copper atom is in a square‐planar environment and 4‐bpytm acts as an N,N′‐bis(monodentate) bridging ligand creating an onedimensional polymeric arrangement. The formiate ligand plays a key role in the supramolecular organization of the chains via CHformiate…Oformiate and CH4bpytm…Oformiate hydrogen bonds.

A recipe for new organometallic polymers and oligomers? Synthesis and structure of an oligo- and a polymeric arrangement of P–S anions

A route to organometallic polymers and oligomers is described using metal complexes with P/S-ligands as examples.

Macrocyclic ligand design: The interaction of selected transition and post-transition metal ions with a 14-membered N 2S 2-donor macrocycle

Interaction of 1,7-dithia-4,11-diazacyclotetradecane ( 1) with nickel(II), copper(II) and silver(I) yields the complexes [NiL(H 2O)(CH 3CN)](ClO 4) 2, [CuL](ClO 4) 2 and [AgL] n (ClO 4) n (L = 1). The log K values for the 1:1 complexes of cobalt(II), copper(II), zinc(II), cadmium(II), silver(I) and lead(II) in 95% MeOH are reported, with the strongest complexes occurring for copper(II) and silver(I). The X-ray structure of the nickel complex shows the four donors of the macrocycle coordinated around cis positions of an octahedron, with water and acetonitrile ligands occupying the remaining cis positions (the latter are trans to the amine donors and the sulfurs occupy trans axial positions). The silver complex is distorted square pyramidal with all macrocyclic donors bound; each sulfur bridges to an adjacent silver centre such that the latter attains a S 3N 2 environment and a cationic zig-zag polymeric arrangement is generated.

AmmoniumO,O-dicyclohexyl phosphorodithioate

The structure of the title compound, NH4+.C12H22O2PS2-, consists of a polymeric arrangement of ammonium cations and O,O-dicyclohexyl phosphorodithioate anions linked through N-H...O and N-H...S hydrogen bonds. These interactions result in the formation of (100) sheets.

2-Anisyl-5-sulfonyldiphenylphosphine Oxide, Solid-State Structure Bearing Covalent Homonuclear Negative and Positive Charge-Assisted Hydrogen Bonds

The X-ray diffraction structure of 2-anisyl-5-sulfonyldiphenylphosphine oxide is reported. The molecule presents two different types of strong covalent homonuclear charge-assisted hydrogen bonds, negative and positive, giving a monodimensional polymeric arrangement. Charges and electron density were calculated for the molecule conformation found by the X-ray diffraction studies.

Extended three-dimensional supramolecular architectures derived from trinuclear (bis-β-diketonato)copper(ii) metallocycles

Neutral trinuclear (triangular) copper(II) complexes of type [Cu3L3] incorporating the 1,4-aryl linked bis-beta-diketonato bridging ligands, 1,1-(1,4-phenylene)-bis(butane-1,3-dione) (H2L2), 1,1-(1,4-phenylene)-bis(pentane-1,3-dione) (H2L3) and 1,1-(1,4-phenylene)-bis(4,4-dimethylpentane-1,3-dione) (H2L4) have been demonstrated to react with selected heterocyclic nitrogen donor bases to generate extended supramolecular architectures whose structures have been confirmed by X-ray diffraction. Thus on reaction with 4,4'-bipyridine (bipy), [Cu3(L2)3] yields polymeric structures of type {[Cu3(L2)3(bipy)(THF)] x 2.75THF}n and {[Cu3(L2)3(bipy)(THF)] x bipy x 0.75THF}(n) while with pyrazine (pyz), {[Cu3(L2)3(pyz)] x 0.5THF}n was obtained. Each of these extended structures contain alternating triangle/linker units in a one-dimensional polymeric chain arrangement in which two of the three copper sites in each triangular 'platform' are formally five-coordinate through binding to a heterocyclic nitrogen atom. Interaction of the multifunctional linker unit hexamethylenetetramine (hmt) with [Cu3(L3)3] afforded an unusual, chiral, three-dimensional molecular framework of stoichiometry [Cu3(L3)3(hmt)]n. The latter incorporates the trinuclear units coordinated to three triply bridging hmt units. In marked contrast to the formation of the above structures incorporating bifunctional linker units and five-coordinate metal centres, the trinuclear platform [Cu3(L2)3] reacts with the stronger difunctional base 1,4-diazabicyclo[2.2.2]-octane (dabco) to yield a highly symmetric trigonal columnar species of type {[Cu3(L4)3(dabco)3] x 3H2O}n in which each copper centre is octahedrally coordinated.

Polymeric arrangements of P–Se anions and a first insight into their reactivity

The reactions of the P/Se-precursor Woollins' reagent [PhP(Se)mu-Se]2 with alkali-metal salts offer new perspectives for the synthesis of metal aggregates containing P-Se anions. Depending on the alkali-metal thiolates polymeric arrangements of [PhPSe3]2- or [PhPSe2Se-SeSe2PPh]2- dianions are observed and the mechanisms of their formation described.

1-[(4-Formylphenyl)hydrazono]naphthalen-2(1H)-one–2-naphthol (1/1)

The crystal structure of the title compound, C17H12N2O2·C10H8O, shows that the mol­ecules are effectively planar in the solid state and the compound exists in the hydrazone form and not the azo form. The hydrazone H atom and carbonyl O atom are linked by an intra­molecular N—H⋯O hydrogen bond. The 2-naphthol molecules are disordered over inversion centres, the asymmetric unit containing half each of two such molecules. The packing can be described as a polymeric arrangement of mol­ecules linked through O—H⋯O hydrogen bonds.

Stabilization of the non-canonical adenine–adeninium base pair by N(7) coordination of Zn(II)

A new zinc (II) compound with 9-ethyladenine (9-EtA) of formula [Zn(9-EtA– N7)Cl 3](9-EtAH) has been synthesized and characterized by X-ray diffraction. Its X-structure consists of an Zn(II) anionic complex and 9-ethyladeninium as counteranion. The Zn(II) complex shows a distorted tetrahedral geometry in which three Cl and an 9-EtA coordinates through N(7) position are the ligands. An indirect chelation via intramolecular H-bond between N(6)H and an Cl ligand is present in the complex. The network of [Zn(9-EtA– N7)Cl 3](9-EtAH) shows interesting features. Thus, self-association of coordinated adenine–adeninium takes place by H-bonding of N(6)–H⋯N(1) and N(6)–H⋯N(7), leading to a polymeric ribbon-like 1D supramolecular arrangement. Ab initio calculations have been applied in order to study the stability of the adenine–adeninium interaction due to the coordination of the Zn(II) to the N(7) position and to compare experimental and theoretical structural data.

1,4-Bis[chloro(hydroxyimino)methyl]benzeneN,N′-dimethylformamide disolvate

The structure of the centrosymmetric title compound, C8H6Cl2N2O2·2C3H7NO, shows that the hydro­ximo­yl chloride substituent has an essentially planar arrangement and the dihedral angle between this plane and the benzene plane is 18.3 (4)°. The hydro­ximo­yl chloride group has a cis configuration. The packing can be described as a polymeric arrangement of mol­ecules linked through O—H⋯O hydrogen bonds.

Transglutaminase-mediated oligomerization of the fibrin(ogen) αC domains promotes integrin-dependent cell adhesion and signaling

AbstractInteractions of endothelial cells with fibrin(ogen) are implicated in inflammation, angiogenesis, and wound healing. Cross-linking of the fibrinogen αC domains with factor XIIIa generates ordered αC oligomers mimicking polymeric arrangement of the αC domains in fibrin. These oligomers and those prepared with tissue transglutaminase were used to establish a mechanism of the αC domain–mediated interaction of fibrin with endothelial cells. Cell adhesion and chemical cross-linking experiments revealed that oligomerization of the αC domains by both transglutaminases significantly increases their RGD (arginyl–glycyl–aspartate)–dependent interaction with endothelial αVβ3 and to a lesser extent with αVβ5 and α5β1 integrins. The oligomerization promotes integrin clustering, thereby increasing cell adhesion, spreading, formation of prominent peripheral focal contacts, and integrin-mediated activation of focal adhesion kinase (FAK) and extracellular signal-regulated kinase (ERK) signaling pathways. The enhanced integrin clustering is likely caused by ordered juxtaposition of RGD-containing integrin-binding sites upon oligomerization of the αC domains and increased affinity of these domains for integrins. Our findings provide new insights into the mechanism of the αC domain–mediated interaction of endothelial cells with fibrin and imply its potential involvement in cell migration. They also suggest a new role for transglutaminases in regulation of integrin-mediated adhesion and signaling via covalent modification of integrin ligands.

Structure and Magnetism of a New Hydrogen-Bonded Layered Cobalt(II) Network, Constructed by the Unprecedented Carboxylate−Phosphinate Ligand [O2(C6H5)PCH2CO2]2-

By hydrothermal reaction of CoCl2 x 6H2O with K2pcc (H2pcc = phenyl(carboxymethyl) phosphinic acid) at 423 K, a novel hybrid material of formula [Co2(pcc)2 (H2O)2] x H2O has been obtained. The compound, which is the first pcc/metal complex reported, exhibits a polymeric arrangement, where cobalt metal ions, linked together by bridging carboxylate and phosphinate oxygens, form infinite chains of edge-shared CoO6 octahedra. The cobalt chains are in turn linked together through important hydrogen-bonding interactions, which create an infinite 2D architecture. The two crystallographically independent cobalt centers, both displaying distorted octahedral coordination, present different environments as one is surrounded by six ligand oxygens and the other by four ligand oxygens and by two water oxygens. Careful magnetic studies performed by a home-built alternating current susceptometer reveal that the system undergoes an antiferromagnetic transition below 2.0 K leading to a canted structure. Field-dependent studies further indicate the occurrence of a metamagnetic transition at a critical field of 650 +/- 50 G.

Anionic dihalotetraacetatodiruthenium(II,III) compounds

The synthesis and characterization of Q[Ru 2Cl 2(μ-O 2CMe) 4] [Q = NEt 4 ( 1), PPh 4 ( 2)], Q[Ru 2Br 2(μ-O 2CMe) 4] [Q = NEt 4 ( 3), PPh 4 ( 4), K ( 5)] and Q[Ru 2I 2(μ-O 2CMe) 4] [Q = NEt 4 ( 6), PPh 4 ( 7)] are described. All compounds have been characterized by elemental analysis, spectroscopic, mass and magnetic data. The structures of 1–3, 5 and 7 are determined by the single crystal X-ray diffraction method. The Ru–Ru bond distances vary from 2.2956(5) to 2.312(3) Å, slightly longer than those observed in the corresponding discrete dinuclear complexes Ru 2X(μ-O 2CR) 4(S) (S = solvent molecule) with Ru–X terminal and in the polymeric arrangement [Ru 2X(μ-O 2CR) 4] n with Ru–X–Ru bonds. The anionic complexes have two axially coordinated halide ligands. The Ru–X bond distance is in accordance with the size of the axial ligand. Thus, the Ru–Cl bond lengths are 2.5396(15) and 2.5627(10) Å, respectively for 1 and 2; the Ru–Br distances are 2.6763(14) ( 3) and 2.6779(4) Å ( 5), and the Ru–I length are 2.897(2) and 2.893(2) Å in 7. The crystal structure determination of complexes 3 and 5 constitutes the first examples of dibromotetracarboxylatodiruthenium(II,III) compounds. The electronic properties of all the compounds are also explored. Their solvatochromism is less accentuated than the corresponding monohalo derivatives.

Cadmium(ii) and mercury(ii) complexes of an NO2S2-donor macrocycle and its ditopic xylyl-bridged analogue

The NO2S2-donor macrocycle (L1) was synthesised from the ring closure reaction between Boc-N-protected 2,2'-iminobis(ethanethiol) (3) and 2,2'-(ethylenedioxy)bis(benzyl chloride) (4) followed by deprotection of the Boc-group. alpha,alpha'-Dibromo-p-xylene was employed as a dialkylating agent to bridge two L1 to yield the corresponding N-linked product (L2). The X-ray structure of L2 (as its HBr salt) is described. A range of Cd(II) and Hg(II) complexes of L1 (6-9) and L2 (10-12) were prepared and characterised. Reaction of HgX2 (X = Br or I) with L1 afforded [Hg(L1)Br]2[Hg2Br6].2CH2Cl2 6 and [Hg(L1)I(2)] 7, respectively. For 6, the Hg(II) ion in the complex cation has a distorted tetrahedral coordination environment composed of S2N donor atoms from L1 and a bromo ligand. In 7 the coordination geometry is highly distorted tetrahedral, with the macrocycle coordinating in an exodentate manner via one S and one N atom. The remaining two coordination sites are occupied by iodide ions. [Hg(L1)(ClO4)]ClO4 8 was isolated from the reaction of Hg(ClO4)2 and L1. The X-ray structure reveals that all macrocyclic ring donors bind to the central mercury ion in this case, with the latter exhibiting a highly distorted octahedral coordination geometry. The O2S2-donors from the macrocyclic ring define the equatorial plane while the axial positions are occupied by the ring nitrogen as well as by an oxygen from a monodentate perchlorato ion. Reaction of Cd(NO3)(2).4H2O with L1 afforded [Cd(L1)(NO3)2](.)0.5CH2Cl2 9 in which L1 acts as a tridentate ligand, binding exo-fashion via its S2N donors. The remaining coordination positions are filled by two bidentate nitrate ions such that, overall, the cadmium is seven-coordinate. Reactions of HgX2(X = Br or I) with L2 yielded the isostructural 2 : 1 (metal : ligand) complexes, [Hg2(L2)Br4] 10 and [Hg2(L2)I(4)] 11. Each mercury ion has a distorted tetrahedral environment made up of S and N donors from an exodentate L2 and two coordinated halides. Contrasting with this, the reaction of L2 with Cd(NO3)(2).4H2O yielded a 1-D coordination network, {[Cd2(L2)(NO3)4].2CH2Cl2}n 12 in which each ring of L2 is exo-coordinated via two S atoms and one N atom to a cadmium ion which is also bound to one monodentate and one bidentate nitrate anion. The latter also has one of its oxygen atom attached to a neighboring cadmium via a nitroso (mu2-O) bridge such that the overall coordination geometry about each cadmium is seven-coordinate. The [Cd(L2)0.5(NO3)2] units are linked by an inversion to yield the polymeric arrangement.

Synthesis of mono- and geminal dimetalated carbanions of bis(phenylsulfonyl)methane using alkali metal bases and structural comparisons with lithiated bis(phenylsulfonyl)imides

The alpha,alpha'-stabilized carbanion complexes [(PhSO2)2CHLi.THF]1, [(PhSO2)2CHNa.THF]2 and [(PhSO2)2CHK]3 were prepared by the direct deprotonation of bis(phenylsulfonyl)methane I in THF with one molar equivalent of MeLi, BuNa and BnK respectively. The geminal dianionic complexes [(PhSO2)2CLi2.THF]4, [(PhSO2)2CNa2.0.55THF]5 and [(PhSO2)2CK2]6 were similarly prepared by the reaction of I with two molar equivalents of MeLi, BuNa and BnK respectively in THF. NMR and MS solution studies of 1-3 are consistent with the formation of charge-separated species in DMSO media. Solutions studies of 4-6, in conjunction with trapping experiments, indicate that the dianions deprotonate DMSO and regenerate the monoanions 1-3. Crystallographic analysis of 1 revealed a 1D chain polymer in which the metal centers are chelated by the bis(sulfonyl) ligands and connect to neighboring units through Li-O(S) interactions. An unexpected feature of 1 is that the polymeric chains are homochiral, since the chelating ligands of the backbone adopt the same relative configuration. Also, the phenyl substituents of each chelate in 1 are oriented in a cisoid manner. The sodium derivative 2 adopts a related solid-state structure, where enantiomeric pairs of chains combine to give a 1D ribbon motif. The lithium bis(phenylsulfonyl)imides [(PhSO2)2NLi.THF]9 and [(PhSO2)2NLi.Pyr2]10 were also prepared and structurally characterized. In the solid state 9 has a similar connectivity to that found for 1 but with heterochiral chains. In comparison, the more highly solvated complex 10 forms a 1D polymeric arrangement without chelation of the ligands and with the phenyl substituents oriented in a transoid fashion.

Synthesis, Properties, and Structural Characterization of Bromo‐ and Iodotetracarboxylatodiruthenium(II,III) Compounds

AbstractThe synthesis and characterization of the compounds [Ru2X(μ‐O2CPh)4]n [X = Br (1), I (2)] and [Ru2X(μ‐O2CC6H4‐p‐OMe)4(H2O)] [X = Br (3) and I (4)] is described. The structures of these compounds were determined by single‐crystal X‐ray diffraction. The molecular structures of [Ru2Br(μ‐O2CCMePh2)4(EtOH)·0.5EtOH] (5·0.5EtOH) and [Ru2I(μ‐O2CCMePh2)4(MeOH)·0.5H2O] (6·0.5H2O) are also reported. Complexes 1 and 2 show a zigzag polymeric arrangement with the diruthenium units linked by bromide and iodide ligands, respectively. The molecular nature of compounds 3 and 4 shows the influence of the axial ligand in the arrangement in the solid state, which contrasts with the polymeric structure found in all chlorodiruthenium(II,III) derivatives with arenecarboxylate bridging ligands. The Ru−Ru bond lengths for all complexes range from 2.2756(17) to 2.2906(7) and 2.273(3) to 2.2965(6) Å for the bromide and iodide derivatives, respectively. This study demonstrates that the nature of the axial ligand plays an important role in the arrangement in the solid state and in the electronic properties of the halotetracarboxylatodiruthenium(II,III) complexes. Thus, the iodo derivatives show an intense solvatochromism, whereas the solvatochromism is slight in the bromo derivatives and is not observed in the chloro complexes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)

Assembly of Positively Charged Porphyrins Driven by Metal Ions: A Novel Polymeric Arrangement of Cationic Metalloporphyrin

Crystallization and crystal structure analysis of chlorohydrates of either tri- or tetracationic copper porphyrins, namely copper(5,10,15-tris(N-methyl-pyridinium-4-yl)-20-pyridine-porphyrinato) (1) and copper(5,10,15,20-tetrakis(N-methyl-pyridinium-4-yl)-porphyrinato), respectively, have been performed. Two crystalline forms, 2 and 3, of the latter have been obtained under different preparation conditions. A novel kind of slipped stack chains of these cationic porphyrins has been detected. The pronounced saddle conformation of the porphyrin reveals pi-like interactions between the peripheral pyrrole Cb-Cb- "double bond" and the metal center. DFT calculations on the isolated porphyrins clearly show the HOMO orbitals with the correct topology to yield a bonding interaction among the stacked porphyrin units. To our knowledge, a slipped stack chain of positively charged porphyrins has never been previously reported, if the arrangement of faced units of monocationic metalloporphyrins or phthalocyanins is excluded.