Kristallstrukturen und spektroskopische Untersuchungen ternärer CuII-Komplexe mit bicyclischen Dicarbonsäuren und N,N-Donor-Liganden

Crystal Structures and Spectroscopic Investigations of Ternary Cu^II-Complexes with Bicyclic Dicarboxylic Acids and N,N-Donor Ligands The synthesis of coordination compounds [CuLdam] · 3H₂O (H₂L = 7-oxa-bicyclo[2.2.1]heptane-2-exo,3-cis-dicarboxylic acid ( 1 ) and its 1-methyl-derivative ( 2 ); dam = ethylendiamine, 1,2- and 1,3-propylendiamine, 2,2′-dipyridyl, 1,10-phenanthroline) has been described. Results of visible and IR spectroscopy and magnetic data are given. In the result of X-ray analyses of [CuL¹dipy] · 3H₂O ( 1 d ) and [CuL²en] · 3H₂O ( 2 a ) the dicarboxylate anions of 1 and 2 proved to be tridentate chelating ligands. In 1 d the Cu atom has an approximately square-pyramidal coordination with the bridging O atom in the apical position. In 2 a , however, the coordination number is extended to six by an O atom of a second [CuL²en] unit resulting in a centrosymmetric complex dimer with octahedrally coordinated Cu atoms. The water molecules do not participate in the coordination of the Cu atoms and form a complicated system of hydrogen bonds in the crystal.     

Zum Komplexbildungsverhalten der 5,6-Dihalogen-7-oxa-bicyclo[2.2.1]heptan-2,3-dicarbonsäure gegenüber 3d-Übergangsmetallen

Complex Formation of 5,6-Dihalogeno-7-oxa-bicyclo[2.2.1]heptane-2,3-dicarboxylic Acid with 3d Transition Elements Carboxylate complexes of bivalent manganese, cobalt, nickel and copper with 5,6-dichloro- and 5,6-dibromo-7-oxa-bicyclo[2.2.1]heptane-2,3-dicarboxylic acid ( 3 and 4 ) have been prepared. For cobalt and nickel two types of complexes are formed: [ML^3/4(H₂O)₃] · H₂O and [ML^3/4(H₂O)₂], the latter is thermodynamically more stable. Manganese and copper form only complexes [MnL^3/4] and [CuL^3/4(H₂O)₂], respectively. The stereochemical configuration of the compounds have been deduced from their spectroscopic and magnetic properties. The metal atoms have been found to be in an octahedral environment. The stability constants of the complexes have been determined by potentiometric measurements. The thermal decomposition of the complexes has been studied by thermogravimetry and differential thermal analysis. The complexes of 3 are thermally more stable than the corresponding ones of 4 . The X-ray structure analysis of [CoL³(H₂O)₃] · H₂O shows a monomeric structure of the complex within the crystal and an octahedral coordination of the metal ion. The dicarboxylate anion acts as a tridentate ligand, the other octahedral sites are occupied by three water molecules. The chlorine atoms are not involved in the network of hydrogen bonds within the crystal packing.     

Synthese,Kristallstrukturen und spektroskopische Untersuchungen von 3d-Übergangsmetall-Komplexen mit Bicyclo[2.2.1]hept-5-en-2-endo,3-cis-dicarbonsäure und N,N-Donorliganden

Synthesis, Crystal Structures and Spectroscopic Investigations of 3d-Transition Metal Complexes with Bicyclo[2.2.1]hept-5-ene-2-endo,3-cis-dicarboxylic Acid and N,N-Donor Ligands The synthesis of coordination compounds of the general type [MLdam(H₂O)₃] · 2.5 H₂O with M = Mn²⁺, Co²⁺, Ni²⁺; H₂L = bicyclo[2.2.1]hept-5-ene-2-endo,3-cis-dicarboxylic acid and dam = 2,2′-dipyridyl, 1,10-phenanthroline has been described. The complexes have been characterized by elementary analysis, infrared and electronic spectra and magnetic susceptibility measurements. The results of X-ray crystal structure analyses of [MnLdipy(H₂O)₃] · 2.5 H₂O ( 1 a ) and [CoLdipy(H₂O)₃] · 2,5 H₂O ( 1 b ) show, that both compounds crystallize isotypically and prove the octahedral coordination of the metal atoms. The dicarboxylate anion is coordinated to the central atom by an O atom of only one carboxylate group, the other one is in the ionic state. One O atom of each carboxylate group makes an intramolecular hydrogen bond with a water molecule of the coordination sphere. The other crystal water molecules form a network of H bonds one with another and with the complex molecules, thus stabilizing the crystal packing.     

Synthese,Kristallstrukturen und Eigenschaften von Lanthanoid(III)-Komplexen mit 7-Oxa-bicyclo[2.2.1]heptan-2,3-dicarbonsäure

Synthesis, Crystal Structures, and Properties of Lanthanoid(III) Complexes with 7-Oxa-bicyclo[2.2.1]heptane-2,3-dicarboxylic Acid The synthesis of coordination compounds [ML(HL)(H₂O)] with M = La³⁺, Ce³⁺, Pr³⁺, Nd³⁺ and H₂L = 7-oxa-bicyclo[2.2.1]heptane-2-exo,3-cis-dicarboxylic acid ( 1 ) has been described. Results of IR spectroscopy and thermal decomposition are given. As a result of X-ray analyses, the four investigated lanthanoid(III) complexes are isotypic. Their stereochemistry approximates to the tri-capped trigonal prism with nine O atoms coordinating the metal atom. The bicyclic ligand acts as a tridentate chelating monoanion HL^? as well as a pentadentate dianion L^2? with both chelating and bridging function. One coordination place at the metal atom is occupied by a water molecule.     

Bis[1‐(2‐hydroxyethyl)‐4,10‐diazapyrazolo[4,3‐b]fluoren‐5(1H)‐one thiosemicarbazonato]zinc(II) dimethylformamide trisolvate monohydrate

In the title Schiff base complex, [Zn(C₁₅H₁₂N₇OS)₂]·3C₃H₇NO·H₂O, each Zn^II atom is six‐coordinated in a distorted octahedral environment by two ligands acting in a tridentate chelating mode through two N atoms and one S atom. The coordination mode of the ligand is nearly planar. There are three dimethylformamide molecules and one water molecule solvating the complex. The coordination behavior of the ligand is compared with that of related ligands in similar complexes.     

Ligand Exchange in Pd(II)-NaCl-H<Subscript>2</Subscript>O and Pd(II)-HCl-H<Subscript>2</Subscript>O Systems: Quantum-Chemical Consideration

The behavior of potassium tetrachloropalladate(II) in media simulating biological liquids is studied. The rate of aquation in aqueous NaCl solutions is shown to be higher than the rate at which the Cl^? ligand enters the inner coordination sphere of the Pd atom. In HCl solutions, the formation of the Pd chloro complexes predominates due to protonation of water molecules in the composition of aqua complexes. The reactions of replacement of the ligands (H₂O molecules and H₃O⁺ ion) in the planar Pd(II) complexes by the chloride ion are studied by the ZINDO/1 method. All the complexes containing H₂O and H₃O⁺ ligands, except for [Pd(H₂O)₄]²⁺, contain intramolecular hydrogen bonds. The ZINDO/1 and RHF/STO-6G(d) calculations revealed “nonclassic” symmetrical O? H?O hydrogen bond in the [[Pd(H₂O)₃(H₃O)]³⁺ and trans-[Pd(H₂O)₂(H₃O)Cl]²⁺ complexes. The replacement of the H₃O⁺ ion by the Cl^? ion at the first three steps is thermodynamically more advantageous than the displacement of water molecules from the metal coordination sphere. The logarithms of stepwise stability constants of Pd(II) chloro complexes are found to correlate linearly with the enthalpies (ZINDO/1, PM3) of reactions of H₂O replacement by Cl^?.     

Coordination‐directed and Hydrogen‐bonded Assembly of Supramolecular Architectures Constructed from Diverse Coordination of Linear,Triangular, Tetragonal Pyramid,Trigonal Bipyramid,and Octahedral Mononuclear Units

Reaction of a imidazole phenol ligand 4‐(imidazlo‐1‐yl)phenol (L) with 3d metal salts afforded four complexes, namely, [Ni(L)₆] · (NO₃)₂ ( 1 ), [Cu(L)₄(H₂O)] · (NO₃)₂ · (H₂O)₅ ( 2 ), [Zn(L)₄(H₂O)] · (NO₃)₂ · (H₂O) ( 3 ), and [Ag₂(L)₄] · SO₄ ( 4 ). All complexes are composed of monomeric units with diverse coordination arrangements and corresponding anions. All the hydroxyl groups of monomeric cations are used as hydrogen‐bond donors to form O–H ··· O hydrogen bonds. However, the coordination habit of different metal ions produces various supramolecular structures. The Ni^II atom shows octahedral arrangement in 1 , featuring a 3D twofold inclined interpenetrated network through O–H ··· O hydrogen bond and π–π stacking interaction. The Cu^II atom of 2 displays square pyramidal environment. The O–H ··· O hydrogen bond from the [Cu(L)₄(H₂O)]²⁺ cation and lattice water molecule as well as π–π stacking produce one‐dimensional open channels. NO₃^– ions and lattice water molecules are located in the channels. 3 is a 3D supramolecular network, in which Zn^II has a trigonal bipyramid arrangement. Two different rings intertwined with each other are observed. The Ag^I in 4 has linear and triangular coordination arrangements. The mononuclear units are assembled into a 1D chain by hydrogen bonding interaction from coordination units and SO₄^2– anions.     

The coordination complex structures and hydrogen bonding in the three‐dimensional alkaline earth metal salts (Mg,Ca, Sr and Ba) of (4‐aminophenyl)arsonic acid

(4‐Aminophenyl)arsonic acid (p‐arsanilic acid) is used as an antihelminth in veterinary applications and was earlier used in the monosodium salt dihydrate form as the antisyphilitic drug atoxyl. Examples of complexes with this acid are rare. The structures of the alkaline earth metal (Mg, Ca, Sr and Ba) complexes with (4‐aminophenyl)arsonic acid (p‐arsanilic acid) have been determined, viz. hexaaquamagnesium bis[hydrogen (4‐aminophenyl)arsonate] tetrahydrate, [Mg(H₂O)₆](C₆H₇AsNO₃)·4H₂O, (I), catena‐poly[[[diaquacalcium]‐bis[μ₂‐hydrogen (4‐aminophenyl)arsonato‐κ²O :O ′]‐[diaquacalcium]‐bis[μ₂‐hydrogen (4‐aminophenyl)arsonato‐κ²O :O ]] dihydrate], {[Ca(C₆H₇AsNO₃)₂(H₂O)₂]·2H₂O}_n , (II), catena‐poly[[triaquastrontium]‐bis[μ₂‐hydrogen (4‐aminophenyl)arsonato‐κ²O :O ′]], [Sr(C₆H₇AsNO₃)₂(H₂O)₃]_n , (III), and catena‐poly[[triaquabarium]‐bis[μ₂‐hydrogen (4‐aminophenyl)arsonato‐κ²O :O ′]], [Ba(C₆H₇AsNO₃)₂(H₂O)₃]_n , (IV). In the structure of magnesium salt (I), the centrosymmetric octahedral [Mg(H₂O)₆]²⁺ cation, the two hydrogen p‐arsanilate anions and the four water molecules of solvation form a three‐dimensional network structure through inter‐species O—H and N—H hydrogen‐bonding interactions with water and arsonate O‐atom and amine N‐atom acceptors. In one‐dimensional coordination polymer (II), the distorted octahedral CaO₆ coordination polyhedron comprises two trans‐related water molecules and four arsonate O‐atom donors from bridging hydrogen arsanilate ligands. One bridging extension is four‐membered via a single O atom and the other is eight‐membered via O :O ′‐bridging, both across inversion centres, giving a chain coordination polymer extending along the [100] direction. Extensive hydrogen‐bonding involving O—H…O, O—H…N and N—H…O interactions gives an overall three‐dimensional structure. The structures of the polymeric Sr and Ba complexes (III) and (IV), respectively, are isotypic and are based on irregular M O₇ coordination polyhedra about the M ²⁺ centres, which lie on twofold rotation axes along with one of the coordinated water molecules. The coordination centres are linked through inversion‐related arsonate O :O ′‐bridges, giving eight‐membered ring motifs and forming coordination polymeric chains extending along the [100] direction. Inter‐chain N—H…O and O—H…O hydrogen‐bonding interactions extend the structures into three dimensions and the crystal packing includes π–π ring interactions [minimum ring centroid separations = 3.4666 (17) Å for (III) and 3.4855 (8) Å for (IV)].     

Syntheses,crystal structures and characterization of divalent transition metal sulfonate complexes with O-phenanthroline

Two new complexes, [Zn(phen)₂(H₂O)₂]2L·H₂O (1) and [Cu(phen)(L)(H₂O)₂]L·3H₂O (2), where HL?= 4-aminobenzenesulfonic acid and phen = o-phenanthroline, have been synthesized and their crystal structures determined by X-ray diffraction. In the complexes the Cu(II) and Zn(II) atoms revealed two different coordination environments. Complex 1 consists of a cation [Zn(phen)₂(H₂O)₂]²⁺, in which Zn(II) is six-coordinated by four nitrogen atoms from two o-phenanthroline molecules and by two water molecules. Complex 2 has two crystallographically unique Cu(II) ions, where Cu(II) ion is five-coordinate with two nitrogen atoms of o-phenanthroline, two water molecules and one sulfonate oxygen atom. The electrochemical behavior and FT-IR of the two compounds have also been studied in detail.     

A novel dinuclear bismuth(III) coordination compound: bis(μ‐pyridine‐2,6‐dicarboxylato)‐κ4O2,N,O6:O6′;κ4O2:O2′,N,O6‐bis[(azido‐κN)(1,10‐phenanthroline‐κ2N,N′)bismuth(III)] tetrahydrate

A novel dinuclear bismuth(III) coordination compound, [Bi₂(C₇H₃NO₄)₂(N₃)₂(C₁₂H₈N₂)₂]·4H₂O, has been synthesized by an ionothermal method and characterized by elemental analysis, energy‐dispersive X‐ray spectroscopy, IR, X‐ray photoelectron spectroscopy and single‐crystal X‐ray diffraction. The molecular structure consists of one centrosymmetric dinuclear neutral fragment and four water molecules. Within the dinuclear fragment, each Bi^III centre is seven‐coordinated by three O atoms and four N atoms. The coordination geometry of each Bi^III atom is distorted pentagonal–bipyramidal (BiO₃N₄), with one azide N atom and one bridging carboxylate O atom located in axial positions. The carboxylate O atoms and water molecules are assembled via O—H...O hydrogen bonds, resulting in the formation of a three‐dimensional supramolecular structure. Two types of π–π stacking interactions are found, with centroid‐to‐centroid distances of 3.461 (4) and 3.641 (4) Å.     

A quantum chemical consideration of ligand exchange in palladium(ii) aqueous and chloride complexes

The behavior of potassium tetrachloropalladate(II) in media simulating biological fluids has been studied. In aqueous solutions of NaCl, the aquation rate is higher than the rate of chloro ligand introduction into the internal coordination sphere of palladium. In HCl solutions, on the contrary, the process of palladium chloro complex formation predominates. The latter is apparently due to protonation of water molecules composing aqua complexes. By means of the ZINDO/1 method, the substitution of ligands – water molecules and hydronium ion – in planar complexes of palladium(II) by chloride ion has been investigated. All complexes containing H₂O and H₃O⁺ ligands, other than [Pd(H₂O)₄]²⁺, have intramolecular hydrogen bonds. In [Pd(H₂O)₃(H₃O)]³⁺ and trans-[Pd(H₂O)₂(H₃O)Cl]²⁺, a “non-classic” symmetric hydrogen bond O ··· H ··· O is established (ZINDO/1, RHF/STO-6G*). By the first three steps the substitution of hydronium ion in the internal sphere of palladium atom is more favorable thermodynamically, compared to water molecules. Logarithms of stepwise stability constants of palladium(II) chloride complexes correlate linearly to enthalpies (ZINDO/1, PM3) of water substitution by chloride ion.     

Three New Thioantimonates(V): Solvothermal Syntheses and Crystal Structures of [M(chxn)3]3(SbS4)2·4H2O (M = Ni,Co) and [Co(dien)2][Co(tren)SbS4]2·4H2O

The three new thioantimonates(V) [Ni(chxn)₃]₃(SbS₄)₂·4H₂O ( I ), [Co(chxn)₃]₃(SbS₄)₂·4H₂O ( II ) (chxn is trans‐1,2‐diaminocyclohexane) and [Co(dien)₂][Co(tren)SbS₄]₂·4H₂O ( III ) (dien is diethylenetriamine and tren is tris(2‐aminoethyl)amine) were synthesized under solvothermal conditions. Compounds I and II are isostructural crystallizing in space group C2/c. The structures are composed of isolated [M(chxn)₃]²⁺ complexes (M = Ni, Co), [SbS₄]^3? anions and crystal water molecules. Short S···N/S···O/O···O separations indicate hydrogen bonding interactions between the different constituents. Compound III crystallizes in space group and is composed of [Co(dien)₂]²⁺ and [Co(tren)SbS₄]^? anions and crystal water molecules. In the cationic complex the Co²⁺ ion is in an octahedral environment of two dien ligands whereas in [Co(tren)SbS₄]^? the Co²⁺ ion is in a trigonal bipyramidal coordination of four N atoms of tren and one S atom of the [SbS₄]^3? anion, i.e., two different coordination polyhedra around Co²⁺ coexist in this compound. Like in the former compounds an extended hydrogen bonding network connects the complexes and the water molecules into a three‐dimensional network.     

Oximato bridged RhIII2MII and RhIIIMI species (MII = Mn, Co, Ni; MI = Cu, Ag)

The reaction of [RhCl₂(HPhL)(PhL)] with M^II(ClO₄)₂·6H₂O in presence of alkali has furnished trinuclear [RhCl₂(PhL)₂]₂M(H₂O)₂·H₂O (HPhL is phenylazobenzaldoxime; M = Mn, Co, Ni). A similar reaction with M^I(PPh₃)₂NO₃ yielded binuclear [RhCl₂(PhL)₂]M(PPh₃)₂ (M = Cu, Ag). In these molecules the oximato group acts as a bridge between Rh^III (bonded at N) and M^II or M^I (bonded at O). In structurally characterized [Rh^IIICl₂(PhL)₂]₂Mn(H₂O)₂.H₂O the centrosymmetric distorted octahedral MnO₆ coordination sphere is spanned by four oximato oxygen atoms and two water molecules lying in trans position. In the lattice the neighbouring molecules are held together by H₂O⋯H₂O⋯H₂O hydrogen bonds generating infinite zigzag chains. The manganese atoms lie parallel to the C-axis, the shortest Mn...Mn distance being 7.992 ?. Magnetic exchange interactions if any are small as seen in room temperature magnetic moments. The manganese system displays a strong EPR signal near g = 2.00. In the complex [RhCl₂(PhL)₂]Cu(PPh₃)₂ the copper atom is coordinated to two oximato oxygen atoms and the two phosphorus atoms in a distorted tetrahedral geometry. The softness of the phosphine ligand is believed to sustain the stable coordination of hard oximato oxygen to soft Cu^I. The coordination sphere of the RhIII atom in both the complexes is uniformly trans-RhN₄Cl₂.     

Coordinate Structures of PrIII, GdIII, TmIII, and YbIII Complexes with Nitrilotriacetic Acids

The crystal and molecular structures of the [Pr^III(nta)(H₂O)₂]·H₂O (nta = nitrilotriacetic acids), K₃[Gd^III(nta)₂(H₂O)]·6H₂O, and K₃[Yb^III(nta)₂]·5H₂O complexes have been determined by single-crystal X-ray structure analyses. In [Pr^III(nta)(H₂O)₂]·H₂O, the Pr^IIINO₈ part forms a nine-coordinate pseudo-monocapped square antiprismatic structure in which one N and three O atoms are from one nta ligand in the same molecule, three O atoms from another nta ligand in the neighboring molecule and two O atoms from two coordinate water molecules. In K₃[Gd^III(nta)₂(H₂O)]·6H₂O, the [Gd^III(nta)₂(H₂O)^3- complex anion has a nine-coordinate pseudo-monocapped square antiprismatic structure in which each nta acts as a tetradentate ligand with one N atom of the amino group and three O atoms of the carboxylic groups. In K₃[Yb^III(nta)₂]·5H₂O, each nta also acts as a tetradentate ligand with one N atom of amino group and three O atoms of the carboxylic groups, but the [Yb^III(nta)₂ ^3- complex anion has an eight-coordinate structure with a distorted square antiprismatic prism. All the results including those for [Tm^III(nta)(H₂O)₂]·2H₂O confirm the inferences on the coordinate structures and coordination numbers of rare earth metal complexes with the nta ligand.     

Crystal structures of some lanthanide(III) complexes with acylhydrazone and their coordination chemistry

Three new lanthanide(III) complexes with N-(2-propionic acid)-salicyloylhydrazone (H₂L, C₁₀H₁₀N₂O₄) ligand [La(HL)₂(NO₃)(H₂O)₂]₃ ·4H₂O(I), [Gd(HL)₃] · 2(C₂H₅)₃ N(II) and [Er(L)(HL)(H₂O)₂] · 2H₂O(III) has been synthesized and characterized by elemental analyses, IR, UV, and molar conductivity. The crystal structures of three complexes have been determined by X-ray single-crystal diffractometer. In complex I, the La³⁺ ion is ten-coordinated by two tridentate ligands, one bidentate nitrate, and two water molecules. In complex II, the Gd³⁺ ion has a coordination number of nine by three tridentate ligands. In complex III, the Er³⁺ ion is eight-coordinated by two tridentate ligands and two water molecules. In all structures, tridentate ligands are coordinated by carboxyl O and acyl O atoms and azomethine N atom to form two stable five-membered rings sharing one side in the keto mode as indicated by the results of crystal structures and infrared spectral analysis.     

Syntheses and Characterization of Three New Compounds Based on Terephthalate and 2‐(2‐Pyridin‐4‐yl‐vinyl)benzimidazole Ligands

Three new compounds based on H₂BDC and PyBImE [H₂BDC = 1,4‐benzenedicarboxylatic acid, PyBImE = 2‐(2‐pyridin‐4‐yl‐vinyl)benzimidazole], namely, [Co(PyBImE)(BDC)(H₂O)₂] ( 1 ), [Co(PyBImE)₂(HBDC)(BDC)_0.5] ( 2 ), and [(HPyBImE)⁺ · (BDC)²–_0.5 · (H₂BDC)_0.5] ( 3 ), were synthesized by hydrothermal methods and characterized by single‐crystal X‐ray diffraction. Compound 1 is a one‐dimensional chain bridged by terephthalate in a bis(monodentate) fashion. In the complex the nitrogen atom from N_BIm and the coordination water molecule complete the coordination sphere. In complex 2 , the dinuclear cobalt units are bridged by terephthalate in a bis(bidentate) fashion into a one‐dimensional chain, but different from complex 1 , the nitrogen atom from N_Py and the oxygen atom from hydrogenterephthalate complete the coordination sphere. Complex 3 is a co‐crystal with PyBImE and H₂BDC in a 1:1 ratio and the transfer of hydrogen atoms leads the complex into a salt. Interesting supramolecular structures are shown due to the hydrogen bonding as well as π ··· π interactions in the three complexes. Thermal and magnetic properties of 1 and 2 were also studied.     

Bis(methanol‐κO)dioxido[3,3′‐(1H‐1,2,4‐triazole‐3,5‐diyl)diphenolato‐κ3O,N4,O′]uranium(VI) methanol monosolvate

The structure of the title compound, [U(C₁₄H₉N₃O₂)O₂(CH₃OH)₂]·CH₃OH, is the first to be reported for an actinide complex including triazole ligands. The U^VI atom exhibits a pentagonal–bipyramidal NO₆ coordination environment, involving two axial oxide ligands [U=O = 1.766 (3) and 1.789 (3) Å], four equatorial O atoms [U—O = 2.269 (3)–2.448 (3) Å] from the ligand and the two coordinated methanol molecules, and one equatorial N atom [U—N = 2.513 (4) Å] from the ligand. In the crystal structure, the complex molecules are linked via intermolecular N—H...O and O—H...O hydrogen bonds to form a two‐dimensional structure.     

Low‐dimensional coordination polymeric structures in alkali metal complex salts of the herbicide (2,4‐dichlorophenoxy)acetic acid (2,4‐D)

The Li, Rb and Cs complexes with the herbicide (2,4‐dichlorophenoxy)acetic acid (2,4‐D), namely poly[[aqua[μ₃‐(2,4‐dichlorophenoxy)acetato‐κ³O¹:O¹:O^1′]lithium(I)] dihydrate], {[Li(C₈H₅Cl₂O₃)(H₂O)]·2H₂O}_n, (I), poly[μ‐aqua‐bis[μ₃‐(2,4‐dichlorophenoxy)acetato‐κ⁴O¹:O^1′:O^1′,Cl²]dirubidium(I)], [Rb₂(C₈H₅Cl₂O₃)₂(H₂O)]_n, (II), and poly[μ‐aqua‐bis[μ₃‐(2,4‐dichlorophenoxy)acetato‐κ⁵O¹:O^1′:O^1′,O²,Cl²]dicaesium(I)], [Cs₂(C₈H₅Cl₂O₃)₂(H₂O)]_n, (III), respectively, have been determined and their two‐dimensional polymeric structures are described. In (I), the slightly distorted tetrahedral LiO₄ coordination involves three carboxylate O‐atom donors, of which two are bridging, and a monodentate aqua ligand, together with two water molecules of solvation. Conjoined six‐membered ring systems generate a one‐dimensional coordination polymeric chain which extends along b and interspecies water O—H...O hydrogen‐bonding interactions give the overall two‐dimensional layers which lie parallel to (001). In hemihydrate complex (II), the irregular octahedral RbO₅Cl coordination about Rb⁺ comprises a single bridging water molecule which lies on a twofold rotation axis, a bidentate O_carboxy,Cl‐chelate interaction and three bridging carboxylate O‐atom bonding interactions from the 2,4‐D ligand. A two‐dimensional coordination polymeric layer structure lying parallel to (100) is formed through a number of conjoined cyclic bridges, including a centrosymmetric four‐membered Rb₂O₂ ring system with an Rb...Rb separation of 4.3312 (5) Å. The coordinated water molecule forms intralayer aqua–carboxylate O—H...O hydrogen bonds. Complex (III) comprises two crystallographically independent (Z′ = 2) irregular CsO₆Cl coordination centres, each comprising two O‐atom donors (carboxylate and phenoxy) and a ring‐substituted Cl‐atom donor from the 2,4‐D ligand species in a tridentate chelate mode, two O‐atom donors from bridging carboxylate groups and one from a bridging water molecule. However, the two 2,4‐D ligands are conformationally very dissimilar, with one phenoxyacetate side chain being synclinal and the other being antiperiplanar. The minimum Cs...Cs separation is 4.4463 (5) Å. Structure extension gives coordination polymeric layers which lie parallel to (001) and are stabilized by intralayer water–carboxylate O—H...O hydrogen bonds.     

Poly[di‐μ‐aqua‐μ‐1,2‐bis(pyridin‐4‐yl)ethene‐κ2N:N′‐tetrakis(4‐iodobenzoato‐κ2O,O′)dicadmium]

Colourless crystals of the title compound, [Cd₂(C₇H₄IO₂)₄(C₁₂H₁₀N₂)(H₂O)₂]_n, were obtained by the self‐assembly of Cd(NO₃)₂·4H₂O, 1,2‐bis(pyridin‐4‐yl)ethene (bpe) and 4‐iodobenzoic acid (4‐IBA). Each Cd^II atom is seven‐coordinated in a pentagonal–bipyramidal coordination environment by four carboxylate O atoms from two different 4‐IBA ligands, two O atoms from two water molecules and one N atom from a bpe ligand. The Cd^II centres are bridged by the aqua molecules and bpe ligands, which lie across centres of inversion, to give a two‐dimensional net. Topologically, taking the Cd^II atoms as nodes and the μ‐aqua and μ‐bpe ligands as linkers, the two‐dimensional structure can be simplified as a (6,3) network.