4.2.8. Reductive Coupling 3109 5. Reaction of Aromatic Compounds 3110 5.1. Electrophilic Substitutions 3110 5.2. Radical Substitution 3111 5.3. Oxidative Coupling 3111 5.4. Photochemical Reactions 3111 6. Reaction of Carbonyl Compounds 3111 6.1. Nucleophilic Additions 3111 6.1.1. Allylation 3111 6.1.2. Propargylation 3120 6.1.3. Benzylation 3121 6.1.4. Arylation/Vinylation 3121 6.1.5. Alkynylation 3121 6.1.6. Alkylation 3121 6.1.7. Reformatsky-Type Reaction 3122 6.1.8. Direct Aldol Reaction 3122 6.1.9. Mukaiyama Aldol Reaction 3124 6.1.10. Hydrogen Cyanide Addition 3125 6.2. Pinacol Coupling 3126 6.3. Wittig Reactions 3126 7. Reaction of R,â-Unsaturated Carbonyl Compounds 3127

Organic Reactions in Aqueous Media with a Focus on Carbon−Carbon Bond Formations: A Decade Update

Polyoxometalates represent a diverse range of molecular clusters with an almost unmatched range of physical properties and the ability to form structures that can bridge several length scales. The new building block principles that have been discovered are beginning to allow the design of complex clusters with desired properties and structures and several structural types and novel physical properties are examined. In this critical review the synthetic and design approaches to the many polyoxometalate cluster types are presented encompassing all the sub-types of polyoxometalates including, isopolyoxometalates, heteropolyoxometalates, and reduced molybdenum blue systems. As well as the fundamental structure and bonding aspects, the final section is devoted to discussing these clusters in the context of contemporary and emerging interdisciplinary interests from areas as diverse as anti-viral agents, biological ion transport models, and materials science.

Polyoxometalate clusters, nanostructures and materials: From self assembly to designer materials and devices

Polyoxometalates (POMs) are discrete anionic metaloxygen clusters which can be regarded as soluble oxide fragments. They exhibit a great diversity of sizes, nuclearities, and shapes. They are built from the connection of {MOx} polyhedra, M being a d-block element in high oxidation state, usually VIV,V, MoVI, or WVI.1 While these species have been known for almost two centuries, they still attract much interest partly based on their large domains of applications. They play a great role in various areas ranging from catalysis,2 medicine,3 electrochemistry,4 photochromism,5 to magnetism.6 This palette of applications is intrinsically due to the combination of their added value properties (redox properties, large sizes, high negative charges, nucleophilicity...). Parallel to this domain, the organic-inorganic hybrids area has followed a similar expansion during the last 10 years. The concept of organic-inorganic hybrid materials * To whom correspondence should be addressed. E-mail: dolbecq@ chimie.uvsq.fr. Chem. Rev. 2010, 110, 6009–6048 6009

Hybrid Organic−Inorganic Polyoxometalate Compounds: From Structural Diversity to Applications

Bioorganometallic Chemistry of Ferrocene

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.

Rhenium Carbonyl Complexes of .beta.-Estradiol Derivatives with High Affinity for the Estradiol Receptor: An Approach to Selective Organometallic Radiopharmaceuticals

Two Anderson-type polyoxomolybdates [FeMo6O18{(OCH2)3CNHCO(4-C5H4N)}2]3– and [MnMo6O18{(OCH2)3CNHCO(4-C5H4N)}2]3– and two Lindqvist-type polyoxovanadates [V6O13{(OCH2)3CCH2OC(O)(4-C5H4N)}2]2– and [V6O13{(OCH2)3CNHCO(4-C5H4N)}2]2– were functionalized with pendant pyridyl groups. The electrochemical analysis revealed reversible redox processes at the heteroatom of the Anderson-type compounds and at the vanadium atoms in the Lindqvist series. Axial coordination of the polyoxometalate-grafted pyridyl groups to the metal ion in [Ru(CO)TPP] (TPP = tetraphenylporphyrin) and [ZnTPP] yielded polyoxometalate–porphyrin assemblies in solution. Evidence for electronic communication between the polyoxometalate and the porphyrin was established by fluorescence spectroscopy. Cyclic voltammetry showed the influence of the porphyrin on the redox process of the polyoxometalate and also nucleophilic attack at the porphyrin skeleton by the pendant pyridyl groups. Implications for the construction of supramolecular functional devices based on these components are discussed.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

Hybrid Organic–Inorganic Porphyrin–Polyoxometalate Complexes

A chromium(III) nickel(II) cyanide-bridged ferromagnetic layered structure with corrugated sheets

Coordination chemistry of the hexavacant tungstophosphate [H2P2W12O48]12−: synthesis and characterization of iron(III) complexes derived from the unprecedented {P2W14O54} fragment

The title reactions of chromium-containing carbene complexes (CO) 5 Cr=(R 1 )N(R 2 R 3 ) (R 1 =H, Me, Ph; R 2 =Me; R 3 =Me, C 3 H 5 , CH 2 C 3 H 5 ; R 2 R 3 =(CH 2 ) 5 ) 8 and (CO) 5 Cr=C[(CH 2 ) 3 C≡CPh]N(R 1 R 2 ) (R 1 =R 2 =Me; R 1 R 2 =(CH 2 ) 5

Jacqueline Vaissermann

Papers

Rhenium Carbonyl Complexes of .beta.-Estradiol Derivatives with High Affinity for the Estradiol Receptor: An Approach to Selective Organometallic Radiopharmaceuticals

Hybrid Organic–Inorganic Porphyrin–Polyoxometalate Complexes

A chromium(III) nickel(II) cyanide-bridged ferromagnetic layered structure with corrugated sheets

Coordination chemistry of the hexavacant tungstophosphate [H2P2W12O48]12−: synthesis and characterization of iron(III) complexes derived from the unprecedented {P2W14O54} fragment

Reaction of aminocarbene complexes of chromium with alkynes. 1. Formation and rearrangement of ketene and nitrogen ylide complexes