Bioorganometallic chemistry: synthesis, structure, and molecular recognition chemistry of (η5-pentamethylcyclopentadienyl)rhodium–DNA/RNA complexes in water

Coordination-driven self-assembly vs dynamic covalent chemistry: versatile methods for the synthesis of molecular metallarectangles

Supramolecular coordination assemblies have a range of potential applications in chemical and biological sciences. Herein, simple modular methods for the synthesis of metallarectangles are described. The desired tetranuclear metallarectangles were synthesized by using coordination-driven self-assembly of half-sandwich rhodium-based organometallic clip units and organic ligands. The reaction of such an organometallic clip with 4-formylpyridine provided a dinuclear molecular tweezer with pendant aldehyde groups, and subsequent [4 + 4] condensation reactions with diamines provides another route to the target metallarectangles in good yields. The same assemblies can also be easily isolated in one-pot procedures by mixing the organometallic clip, diamines and 4-formylpyridine.

Half-sandwich type rhodium(iii)–aminohydroxamate complexes: the role of the position of the amino group in metal ion binding

Relative order of the pH-dependent conditional stability of the hydroxamate type (O,O) and (N_amino,N_hydroxamato) chelates determines the coordination modes in the various mono- and dinuclear complexes of [(η⁵-Cp*)Rh^III(H₂O)₃]²⁺ with α-, β- and γ-aminohydroxamic acids.

Bismuth⋯π arene versus bismuth⋯halide coordination in heterocyclic diorganobismuth(iii) compounds with transannular N→Bi interaction

The hypervalent diorganobismuth(iii) halides of type [RCH₂N(CH₂C₆H₄)₂]BiX, (R = Ph, Bz, and MeO) show a strong tendency to associate either by Bi⋯X or by Bi⋯π arene secondary interactions.

An experimental and quantum chemical study on the non-covalent interactions of a cyclometallated Rh(iii) complex with DNA and BSA

The interaction of a new cyclometallated Rh(iii) complex with DNA and BSA was investigated. The three-layer ONIOM method was employed to calculate the interaction energy between DNA and the complex.

Thyminate(2-)-bridged cyclic tetranuclear rhodium(III) complexes formed by a template of a sodium, calcium or lanthanoid ion

In the thyminate(2-)-bridged tetranuclear Cp*Rh(III) complexes incorporating a Na(+), Ca(2+) or Ln(3+) cation, homochiral aggregation of four Rh(III) centres was achieved to form metallacalix[4]arene-type clusters. The thyminate(2-) bridged two Rh(III) and the third metal ion with a μ3-1κN(1):2κ(2)N(3),O(2):3κO(2) mode in the Na(+) and Ca(2+) complexes, while in the Ln(3+) analogues it exhibited a different bridging mode, μ3-1κN(1):2κ(2)N(3),O(4):3κO(2).

Bulky metallocavitands with a chiral cavity constructed by aluminum and magnesium atrane-likes: enantioselective recognition and separation of racemic alcohols

Novel tetranuclear metallocavitands with a chiral cavity were synthesized via self-assembly of aluminum/magnesium atrane-likes and were successfully applied to the chiral resolution of 2-butanol.

Half-sandwich iridium- and rhodium-based organometallic architectures: rational design, synthesis, characterization, and applications

CONSPECTUS: Over the last two decades, researchers have focused on the design and synthesis of supramolecular coordination complexes, which contain discrete functional structures with particular shapes and sizes, and are similar to classic metal-organic frameworks. Chemists can regulate many of these systems by judiciously choosing the metal centers and their adjoining ligands. These resulting complexes have unusual properties and therefore many applications, including molecular recognition, supramolecular catalysis, and some applications as nanomaterials. In addition, researchers have extensively developed synthetic methodologies for the construction of discrete self-assemblies. One of the most important challenges for scientists in this area is to be able to synthesize target structures that can be controlled in both length and width. For this reason, it is important that we understand the factors leading to special shapes and sizes of such architectures, especially how starting building blocks and functional ligands affect the final conformations and cavity sizes of the resulting assemblies. Towards this goal, we have developed a wide range of different organometallic architectures by rationally designing metal-containing precursors and organic ligands. In this Account, we present our recent work, focusing on half-sandwich iridium- and rhodium-based organometallic assemblies that we obtained through rational design. We discuss their synthesis, structures, and applications for the encapsulation of guests and enzyme-mimicking catalysis. We first describe a series of self-assembled organometallic metallarectangles and metallacages, which we constructed from preorganized dinuclear half-sandwich molecular clips and suitable pyridyl ligands. We extended this strategy to tune the size of the obtained rectangles, creating large cavities by introduction of larger molecular clips. The cavity was found to exhibit selective and reversible CH2Cl2 adsorption properties while retaining single crystallinity. By using suitable molecular clips, we found we could use a number of metallacycles as organometallic templates to direct photochemical [2 + 2] cycloaddition reactions, even in the solid state. Due to their chemical stability and potential applications in catalytic reactions, researchers are giving significant attention to complexes with cyclometalated backbones. We also highlight our efforts to develop efficient approaches to utilize cyclometalated building blocks for the formation of organometallic assemblies. By incorporation of imine ligands or benzoic acids, bipyridine linking subunits, and half-sandwich iridium or rhodium fragments, we built up a series of cationic and neutral metallacycles through cyclometalation-driven self-assembly. In addition, we have developed an efficient route to carborane-based metallacycles, involving the exploitation of metal-induced B-H activation. The method can provide prism-like metallacages, which are efficient hosts for the recognition of planar aromatic guests. This effort provides an incentive to generate new building blocks for the construction of organometallic assemblies. Taken together, our results may lead to a promising future for the design of complicated enzyme-mimetic-catalyzed systems.

Medicinal organometallic chemistry: designing metal arene complexes as anticancer agents

The field of medicinal inorganic chemistry is rapidly advancing. In particular organometallic complexes have much potential as therapeutic and diagnostic agents. The carbon-bound and other ligands allow the thermodynamic and kinetic reactivity of the metal ion to be controlled and also provide a scaffold for functionalization. The establishment of structure-activity relationships and elucidation of the speciation of complexes under conditions relevant to drug testing and formulation are crucial for the further development of promising medicinal applications of organometallic complexes. Specific examples involving the design of ruthenium and osmium arene complexes as anticancer agents are discussed.