The development in the field of coordination polymers or metal-organic coordination networks, MOCNs (metal-organic frameworks, MOFs) is assessed in terms of property investigations in the areas of catalysis, chirality, conductivity, luminescence, magnetism, spin-transition (spin-crossover), non-linear optics (NLO) and porosity or zeolitic behavior upon which potential applications could be based.

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Engineering coordination polymers towards applications

: The unpolarized absorption and circular dichroism spectra of the fundamental vibrational transitions of the chiral molecule, 4-methyl-2-oxetanone, are calculated ab initio. Harmonic force fields are obtained using Density Functional Theory (DFT), MP2, and SCF methodologies and a 5S4P2D/3S2P (TZ2P) basis set. DFT calculations use the Local Spin Density Approximation (LSDA), BLYP, and Becke3LYP (B3LYP) density functionals. Mid-IR spectra predicted using LSDA, BLYP, and B3LYP force fields are of significantly different quality, the B3LYP force field yielding spectra in clearly superior, and overall excellent, agreement with experiment. The MP2 force field yields spectra in slightly worse agreement with experiment than the B3LYP force field. The SCF force field yields spectra in poor agreement with experiment.The basis set dependence of B3LYP force fields is also explored: the 6-31G* and TZ2P basis sets give very similar results while the 3-21G basis set yields spectra in substantially worse agreements with experiment. jg

Ab initio calculation of vibrational absorption and circular dichroism spectra using density functional force fields

The nanoporous metal-organic framework Fe2(azpy)4(NCS)4.(guest) (azpy is trans-4,4'-azopyridine) displays reversible uptake and release of guest molecules and contains electronic switching centers that are sensitive to the nature of the sorbed guests. The switching of this material arises from the presence of iron(II) spin crossover centers within the framework lattice, the sorbed phases undergoing "half-spin" crossovers, and the desorbed phase showing no switching property. The interpenetrated framework structure displays a considerable flexibility with guest uptake and release, causing substantial changes in the local geometry of the iron(II) centers. The generation of a host lattice that interacts with exchangeable guest species in a switchable fashion has implications for the generation of previously undeveloped advanced materials with applications in areas such as molecular sensing.

https://science.sciencemag.org/content/sci/298/5599/1762.full.pdf

Guest-Dependent Spin Crossover in a Nanoporous Molecular Framework Material

Advances in copper complexes as anticancer agents.

As a result of the different degrees of stabilization experienced by the 4f, 5d, and 6s orbitals occurring upon ionization of the neutral metal, the lanthanides (La-Lu, Z ) 57-71) exist almost exclusively in their trivalent state Ln(III) ([Xe]4fn, n ) 0-14) in coordination complexes or supramolecular assemblies.1 Except for some arene compounds involving bulky substituted benzenes or cyclo-octatetraenes,2 covalence plays a minor role in Ln-ligand dative bonds and the nature of the coordination sphere is controlled by a subtle interplay between electrostatic interactions and interligand steric constraints.3 Variable coordination numbers (6 e CN e 12) and geometries are thus observed in lanthanide complexes, leading to limited success in the design of molecular architectures with predetermined structures.3,4 Although rigid or semirigid receptors may help to control the coordination sphere according to the lock-and-key and induced fit concepts,5 detailed studies of lanthanide solvates with water or acetonitrile suggest that trivalent lanthanides display a tendency to adopt nine-coordinate tricapped trigonal prismatic (TTP) arrangements around the metal ion in the solid state. In solution, the picture is a little more subtle:6 in water, for instance, large Ln(III) ions at the beginning of the series (Ln ) La-Nd) adopt TTP geometries, which are gradually transformed into eight-coordinate square antiprismatic (SAP) arrangements for small Ln(III) ions (Ln ) Tb-Lu), equilibria between CN ) 8 and CN ) 9 being observed for Ln ) Nd-Tb.7 The systematic contraction of the ionic radii observed when going from Ln ) La to Lu (often referred to as the lanthanide contraction)8 explains this trend and increases electrostatic bonding for heavier lanthanides, but this variation is so smooth and limited (15% contraction between La and Lu and ≈1% between two successive lanthanides) that selective recognition and incorporation into organized supramolecular architectures remains challenging.5 A rational access to extended polymetallic lanthanide-containing assemblies with predictable and controlled geometries is consequently very limited, and pioneer work in this field has focused on poorly characterized intricate mixtures of complexes in solution which are ‘transformed’ into well-defined solid-state clusters or networks through crystallization processes involving a rich palette of † Institute of Molecular and Biological Chemistry, Lausanne. E-mail: Jean-Claude.Bunzli@epfl.ch. ‡ Department of Inorganic, Analytical and Applied Chemistry, Geneva. E-mail: Claude.Piguet@chiam.unige.ch.

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Lanthanide-containing molecular and supramolecular polymetallic functional assemblies.

Structure, chemical and photochemical reactivity and biological activity of some ruthenium amine nitrosyl complexes

Metals in anticancer therapy: Copper(II) complexes as inhibitors of the 20S proteasome

EPR and NMR study of the spin-crossover transition in bis(4,4'-bi-1,2,4-triazole)bis(thiocyanato)iron hydrate and bis(4,4'-bi-1,2,4-triazole)bis(selenocyanato)iron hydrate. X-ray structure determination of Fe(4,4'-bi-1,2,4-triazole)2(SeCN)2.cntdot.H2O

Species 1−6 are [MIII(L)2]ClO4 complexes formed with the PhO-−CHN−CH2−Py imines, (LI)- and (LtBuI)-, and PhO-−CH2−NH−CH2−Py amines, (LA)- and (LtBuA)-, in which PhO- is a phenolate ring and Py is a pyridine ring and the prefix tBu indicates the presence of tertiary butyl groups occupying the positions 4 and 6 of the phenol ring. Monometallic species with d5 high-spin iron (1, 2, 3, 4) and d10 gallium (5, 6) were synthesized and characterized to assess the influence of the ligand rigidity and the presence of tertiary butyl-substituted phenol rings on their steric, electronic, and redox behavior. Characterization by elemental analysis, mass spectrometry, IR, UV−visible, and EPR spectroscopies, and electrochemistry has been performed, and complexes [FeIII(LtBuI)2]ClO4 (2), [FeIII(LtBuA)2]ClO4 (4), and [GaIII(LtBuI)2]ClO4 (5) have been characterized by X-ray crystallography. The crystal structures show the imine ligands meridionally coordinated to the metal centers, whereas the amine ligands are coordinate in...

Influence of ligand rigidity and ring substitution on the structural and electronic behavior of trivalent iron and gallium complexes with asymmetric tridentate ligands.

Bruce R. McGarvey

Papers

Structure, chemical and photochemical reactivity and biological activity of some ruthenium amine nitrosyl complexes

Metals in anticancer therapy: Copper(II) complexes as inhibitors of the 20S proteasome

EPR and NMR study of the spin-crossover transition in bis(4,4'-bi-1,2,4-triazole)bis(thiocyanato)iron hydrate and bis(4,4'-bi-1,2,4-triazole)bis(selenocyanato)iron hydrate. X-ray structure determination of Fe(4,4'-bi-1,2,4-triazole)2(SeCN)2.cntdot.H2O

Influence of ligand rigidity and ring substitution on the structural and electronic behavior of trivalent iron and gallium complexes with asymmetric tridentate ligands.

Survey of ligand field parameters of strong field d5 complexes obtained from the g matrix