A Zn(II) Metallocycle as Platform to Assemble a 1D + 1D → 1D Polyrotaxane via π···π Stacking of an Ancillary Ligand

A new [Zn2L2] metallocycle bearing two metal centers that can coordinate ancillary ligands and a pocket suitable to host guest molecules is reported. These two features are exploited by reacting the metallocycle with a pyridine ligand to self-assemble in the solid state an extended intertwined system with the rare 1D + 1D → 1D topology. This interpenetrated architecture is supported by π···π stacking between two pyridine units of two different metallocycles in the pocket of a third metallocycle.

Amalgamating 4′-substituted 4,2′:6′,4′′-terpyridine ligands with double-helical chains or ladder-like networks

Hg^II-mediated self-assembly of metal–organic coordination polymers based on 4,2′:6′,4′′-terpyridine derivatives is for the first time presented and the structural diversity dependent upon the use of 4′-substituents of ligand is revealed.

Solvent and anion facilitated conformational changes in benzylamine substituted thiazolamine

Solvent and anion guided conformational adjustments in the syn–anti–syn form of N,N′-(1,4-phenylene-bis(methylene))-bis(5-methylthiazol-2-amine) and the utility of nitrate ions in stabilizing the anti–anti–anti form are established.

A temperature-induced order-disorder phase transition in a 4-substituted 4,2':6',4''-terpyridine

Crystals of 4'-(isoquinolin-4-yl)-4,2':6',4''-terpyridine (iqtp), C24H16N4, grown from an ethanol solution, undergo a reversible first-order single-crystal to single-crystal phase transition at Tc in the range 273-275 K, from a disordered higher-temperature phase [form (I)] in the space group P21/c, with one single molecule in the asymmetric unit, to an ordered lower-temperature one [form (II)] in the space group P21/n, with two independent molecules in the asymmetric unit. There is a group-subgroup relationship linking (I)-(II), due to cell doubling and the disappearance of a number of symmetry operations. In addition to X-ray diffraction, the transition has been monitored by Raman spectroscopy and differential scanning calorimetry, the latter disclosing an enthalpy change of 0.72 (6) kJ mol(-1). Variations of the unit-cell parameters with temperature between 170 and 293 K are presented. The evolution of diffraction spots in the vicinity of the transition temperature shows the coexistence of both phases, confirming the first-order character of the transition. Structural details of both phases are analyzed and intermolecular interactions compared in order to investigate the mechanism of the phase transition. A three-dimensional Hirshfeld surface analysis was performed to corroborate the significant changes in the intermolecular features.

4,2':6',4''-Terpyridines: diverging and diverse building blocks in coordination polymers and metallomacrocycles

4,2':6',4''-Terpyridine (4,2':6',4''-tpy) is one of the less well documented isomers of the well-established bis-chelating 2,2':6',2''-terpyridine. The N-donors of the outer rings in 4,2':6',4''-tpy subtend an angle of 120°, leading to a description of 4,2':6',4''-tpy as a divergent ligand. Because it typically binds metal ions through the outer N-donors only, 4,2':6',4''-tpy is an ideal linker for combination with metal nodes (often geometrically flexible d(10) ions) in coordination polymers and metallomacrocyclic complexes. The facile functionalization of terpyridines in the 4'-position allows access to a suite of 4'-X-4,2':6',4''-tpy ligands in which the 4'-substituent, X, can be selected to assist in directing the metal-ligand assembly process. This overview of recent advances in the chemistry of 4,2':6',4''-tpy and its 4'-substituted derivatives looks at relationships within a series of chiral polymers, competition between the formation of metallocyclic complexes versus polymers, and the use of extended aryl systems to encourage the formation of coordination polymers in which π-stacking of arene domains dominates in the assembly process. Use of metal(ii) acetates is key to the formation of paddle-wheel and larger cluster nodes that direct the assembly of both predetermined and unexpected architectures.

Divergent 4,2′:6′,4′′- and 3,2′:6′,3′′-terpyridines as linkers in 2- and 3-dimensional architectures

This Highlight illustrates the strategies applied to encourage the formation of 2- and 3-dimensional metal–organic architectures as opposed to 1-dimensional chains using 4,2′:6′,4′′- and 3,2′:6′,3′′-terpyridines as organic linkers.

Diverse zinc(ii) coordination assemblies built on divergent 4,2′:6′,4′′-terpyridine derivatives: syntheses, structures and catalytic properties

Diverse Zn(ii) metal–organic assemblies of 4,2′:6′,4′′-terpyridine derivatives were structurally characterized and applied for catalytic transesterification of phenyl acetate with alcohols.

Synthesis of discrete Re(i) di- and tricarbonyl assemblies using a [4 × 1] directional bonding strategy

Discrete assembly of two Re(i) squares was achieved by a simple [4 × 1] strategy where the complexes, [Re(4-pytpy-κ²N)(CO)₃Br] and [Re(4-pytpy-κ³N)(CO)₂Br], act as their own ligands. The properties of the assemblies and their precursors are described along with solid-state X-ray diffraction studies.

Assembling mono-, di- and tri-nuclear coordination complexes with a ditopic analogue of 2,2′:6′,2′′-terpyridine: syntheses, structures and catalytic studies

Diverse metal assemblies based on a ditopic analogue of 2,2′:6′,2′′-terpyridine are structurally characterized and applied for catalytic aerobic alcohol oxidation.

Environmental control in the assembly of metallomacrocycles and one-dimensional polymers with 4,2′:6′:4′′-terpyridine linkers and zinc(ii) nodes

One-dimensional polymers and discrete [4 + 4] and [6 + 6] metallocycles assemble in reactions of 4′-aryl-substituted 4,2′:6′:4′′-terpyridines with ZnX₂ in the presence of potential arene guest molecules.