An introduction to the virtual issue on Coordination polymers

Editorial

Acetate and acetamide complexes of [Ni(Me₄[12]aneN₄)]PF₆: a tale of two ligands

Both acetate and acetamide anions are well known as ligands, but why are there so few complexes with an acetamide as a chelon? A side-by-side comparison suggests these ligands could be viewed as different electronic versions of each other.

Phase-transformation-induced twinning of an iron(III) calix[4]pyrrolidine complex

An iron(III) calix[4]pyrrolidine complex undergoes a slow phase transformation at ca 173 K from monoclinic space group P2₁/n to the maximal non-isomorphic subgroup, triclinic space group P, which is accompanied by nonmerohedral twinning. The NH H atoms are directed below the planes of the macrocycles and are hydrogen bonded to the coordinated Cl⁻ ions. There are also intra­molecular C—H⋯Cl hydrogen bonds present in both forms.

A three-dimensional Pb^II coordination framework: poly[[μ₄-(E)-2,2′-(diazene-1,2-di­yl)dibenzoato]di­methanol­lead(II)]

A lead(II) complex has been prepared by reaction of Pb(OAc)₂·2H₂O (OAc is acetate) with 2,2′-(diazene-1,2-di­yl)di­benzoic acid and 4,4′-bi­pyridine in MeOH–H₂O at 363 K. Single-crystal X-ray diffraction analysis reveals that the complex possesses a three-dimensional framework with a 4¹²6³ topology.

A one-dimensional cobalt(II) coordination polymer based on 2,4′-oxydi­benzoic acid: poly[[[di­aqua­bis­[2-(4-carb­oxy­phen­oxy)benzoato-κO¹]cobalt(II)]-μ-4,4′-bi­pyridine-κ²N:N′] dihydrate]

In a new one-dimensional cobalt(II) coordination polymer with 2-(4-carb­oxy­phen­oxy)benzoate (Hoba⁻) and 4,4′-bi­pyridine (bipy) ligands, the Co^II ions are connected by bipy ligands to form an infinite one-dimensional chain. O—H⋯O hydrogen bonding extends these chains into a two-dimensional supra­molecular architecture.

Disentangling steric and electronic factors in monomeric bis­(2-bromo-4-chloro-6-{[(2-hy­droxy­eth­yl)imino]­meth­yl}phenolato-κ²N,O)copper(II)

In a centrosymmetric bis-substituted 2-bromo-4-chloro-6-{[(2-hy­droxy­eth­yl)imino]­meth­yl}phenolate copper(II) complex, the Cu^II centre is coordinated in a square-planar geometry and the hydrogen-bond network is built from infinite two-dimensional layers formed by O—H⋯O hydrogen bonds between hy­droxy­ethyl groups.

Packing considerations of 10-oxa-9-bora­phenanthrene derivatives

The crystal structures of three products of the reaction of 2-phenyl­phenol and BCl₃ have been determined. The structures show intriguing packing patterns and an inter­esting case of pseudosymmetry. In addition, one of the two polymorphs has a primitive monoclinic crystal system, but it is twinned and emulates an ortho­rhom­bic C-centred structure.

A 16-connected three-dimensional hydrogen-bonding network in tetra­kis­(4-amino­pyridinium) perylene-3,4,9,10-tetra­carboxyl­ate octa­hydrate

Numerous charge-assisted hydrogen bonds and π–π inter­actions link the counter-ions of tetra­kis­(4-amino­pyridinium) perylene-3,4,9,10-tetra­carboxyl­ate octa­hydrate into a three-dimensional framework. From the viewpoint of topology, each anion acts as a 16-connected node by hydrogen bonding to six cations and ten water mol­ecules to yield a highly connected hydrogen-bonding framework.

A simple hydrated salt with a complex hydrogen-bonding network: tetra­kis­(5-amino-3-carb­oxy-4H-1,2,4-triazol-1-ium) hexa­chlorido­cadmate(II) tetra­hydrate

In a hydrated cadmium chloride salt, the asymmetric unit comprises two N-protonated 5-amino-3-carb­oxy-4H-1,2,4-triazol-1-ium cations, half a [CdCl₆]⁴⁻ anion and two mol­ecules of water. Alternating layers of cations and anions are arranged along the [101] direction, forming a three-dimensional supra­molecular network via a combination of hydrogen-bonding and aromatic stacking inter­actions.

(E)-3-{4-[(7-Chloro­quinolin-4-yl)­oxy]-3-meth­oxy­phenyl}-1-(4-methyl­phenyl)prop-2-en-1-one: a ladder-like structure resulting solely from π–π stacking inter­actions

Two independent π–π stacking inter­actions link the mol­ecules of (E)-3-{4-[(7-chloro­quinolin-4-yl)­oxy]-3-meth­oxy­phenyl}-1-(4-methyl­phen­yl)prop-2-en-1-one, but hydrogen bonds are absent from the structure.

Hydrogen bonding in 4-nitro­benzene-1,2-di­amine and two hydro­halide salts

4-Nitro­benzene-1,2-di­amine and two hydro­halide salts exhibit extensive hydrogen bonding resulting in two- and three-dimensional networks. The structural results are used in conjuction with DFT calculations to estimate the strength of the N—H⋯O(nitro) inter­actions.

A comparative study of two polymorphs of L-aspartic acid hydro­chloride

The crystal structures of two polymorphs of L-aspartic acid hydro­chloride revealed three- and two-dimensional hydrogen-bonding networks for the triclinic and ortho­rhom­bic polymorphs, respectively. The polymorphs share common structural features; however, the conformations of the L-aspartate cations and the crystal packings are different.

Poly[(μ₅-3-carb­oxy­benzene-1,2-di­carboxyl­ato)lead(II)]: a helical lead(II) coordination polymer

A chiral two-dimensional lead(II) coordination polymer containing right-handed helical chains has been prepared under hydro­thermal conditions using an achiral organic 3-carb­oxy­benzene-1,2-di­carboxyl­ate linker ligand. The thermogravimetric and optical properties are also reported.

A low-temperature modification of hexa-tert-butyl­disilane and a new polymorph of 1,1,2,2-tetra-tert-butyl-1,2-di­phenyl­disilane

Crystals of hexa-tert-butyl­disilane undergo a reversible phase transition at 179 (2) K. The space group changes from Ibca (high temperature) to Pbca (low temperature), but the lattice constants a, b and c do not change significantly during the phase transition. In a new polymorph of 1,1,2,2-tetra-tert-butyl-1,2-di­phenyl­disilane, two independent mol­ecules have rather similar conformations.

Coordination polymer chains built from Cu^II and adipate ions linked by hydrogen bonds to form a three-dimensional framework structure

Coordination polymer chains built from Cu^II and adipate ions are linked into a framework structure by hydrogen bonds and π–π stacking inter­actions involving 2,2′-bi­pyridine and 1,1,3,3-tetra­cyano-2-eth­oxy­propenide components.

Oxazolochlorins. 14.

The crystal structure of 8-oxo-5,10,15,20-tetra­phenyl-7-oxaporphyrin N²⁴-oxide is compared with its isomer, 8-oxo-5,10,15,20-tetra­phenyl-7-oxaporphyrin N²²-oxide, carrying the N-oxide at the opposing nitro­gen, and the parent tetra­aryl­porphyrin N-oxide. A detailed conformational analysis reveals subtle differences in the nonplanar conformations of their chromophores.

A three-dimensional cadmium(II) coordination polymer: poly[[[μ-4,4′-(propane-1,3-diyl)di­pyridine-κ²N:N](μ-3,3′-thio­dipropionato-κ³O,O′:O)cadmium(II)] mono­hydrate]

In a Cd^II coordination polymer formed by 3,3′-thio­dipropionate and 4,4′-(propane-1,3-diyl)di­pyridine ligands, the Cd^II centres are bridged through carboxyl­ate O atoms and pyridine N atoms to form two different one-dimensional chains which intersect to form a two-dimensional layer. These two-dimensional layers are linked by S atoms to form a three-dimensional network.

A new two-dimensional manganese(II) coordination polymer based on thio­phene-3,4-di­carb­oxy­lic acid

A manganese(II) coordination polymer based on thiophene-3,4-dicarboxylate was synthesized hydrothermally. The thiophene-3,4-dicarboxylate ligand adopts a novel hexadentate chelating and μ₅-bridging coordination mode.

[2,5-Bis(2,2′-bi­pyridyl-6-yl)-3,4-di­aza­hexa-2,4-diene]di­chlorido­mangan­ese(II): from a mononuclear compound to a three-dimensional supra­molecular framework through C—H⋯Cl hydrogen bonds and π–π stacking inter­actions

A supra­molecular architecture based on C—H⋯Cl and π–π stacking inter­actions was obtained for a mononuclear Mn^II complex incorporating chloride and 2,5-bis­(2,2′-bipyridyl-6-yl)-3,4-di­aza­hexa-2,4-diene ligands.

Controllable assembly of a three-dimensional metal–organic supra­molecular framework displaying hydrogen-bonding and π–π stacking inter­actions

A one-dimensional double-chain zinc(II) complex with phthalate and 2-[3-(pyridin-2-yl)-1H-pyrazol-1-yl]acetate (PPAA⁻) ligands has been prepared by solvothermal reaction of 2-[3-(pyridin-2-yl)-1H-pyrazol-1-yl]aceto­nitrile (PPAN) with zinc(II), the PPAN being hydrolyzed to PPAA⁻. The one-dimensional double chains are extended into a three-dimensional supra­molecular architecture via hydrogen-bonding and π–π stacking inter­actions.

The effect of coordinated water on the connectivity of uranium(IV) sulfate x-hydrate: [U(SO₄)₂(H₂O)₅]·H₂O and [U(SO₄)₂(H₂O)₆]·2H₂O, and a comparison with other known structures

Two new uranium(IV) sulfate x-hydrates, where x is the total number of coordinated plus solvent waters, have been characterized and compared to other known uranous sulfate x-hydrates. As the number of coordinated waters increases, the structure transitions from being fully crosslinked through sulfate bridging in three dimensions in the anhydrous compound, through sheet and chain linking in the tetra- and hexahydrate, to fully unlinked molecules in the octa- and nonahydrate.