Synthesis, structural characterisation and solution behaviour of high symmetry lanthanide triflate complexes with the sterically demanding phosphine oxides Cy3PO and tBu3PO

The synthesis and characterisation of lanthanide trifluoromethane sulfonate (Ln(OTf)3) complexes with tricyclohexylphosphine oxide, (Cy3PO) and tritert-butylphosphine oxide, (tBu3PO) is described. The structures of [Ln(H2O)5(Cy3PO)2].2R3PO.[OTf]3 (Ln = Pr, Tm R = Cy Ln = Nd R = tBu) are pentagonal bipyramidal with an equatorial plane of five H2O and two axial Cy3PO. The remaining Cy3PO molecules are hydrogen bonded to the coordinated water molecules as are the triflate anions. Solution NMR spectroscopy shows the triflate ions remain associated with the complexes in CDCl3 solution. Lanthanide induced shifts in the 19-F and 31-P NMR spectra confirm that one structure is present for all the lanthanides with an additional structure for the heavier metals. The acidity of the complexes has been examined by 31-P NMR spectroscopy of the reactions between [Ln(H2O)5(Cy3PO)2].2Cy3PO.[OTf]3 (Ln = La, Eu, Er, Lu) and phosphines PR3 (R = Ph, mesityl and Cy) and Ph2PC2H4PPh2 and Ph2PC3H6PPh2 . Protonation of the more basic phosphines and H-bonding to the less basic phosphines is observed

Constructing chiral MOFs by functionalizing 4,2′:6′,4″-terpyridine with long-chain alkoxy domains: rare examples of neb nets

Reactions of 4′-(4- n alkyloxyphenyl)-4,2′:6′,4″-terpyridines (alkyl = hexyl or nonyl) with CoIJNCS) 2 lead to three structurally characterized chiral 3D assemblies which adopt rare neb topologies. For the n hexyl-functionalized ligands, both enantiomorphic lattices of the neb nets (crystallizing in the tetragonal space groups P4 1 2 1 2 and P4 3 2 1 2, respectively) are presente

To bend or not to bend – are heteroatom interactions within conjugated molecules effective in dictating conformation and planarity?

We consider the roles of heteroatoms (mainly nitrogen, the halogens and the chalcogens) in dictating the conformation of linear conjugated molecules and polymers through non-covalent intramolecular interactions. Whilst hydrogen bonding is a competitive and sometimes more influential interaction, we provide unambiguous evidence that heteroatoms are able to determine the conformation of such materials with reasonable predictability

The use of the triptycene framework for observing O⋯C=O molecular interactions

The triptycene skeleton has been used to measure (1,5) interactions between aldehyde groups, placed at both sp³ centres, and hydroxy or methoxy groups, placed at the respective ortho position on a benzene ring; HO⋯CHO interactions of 2.621–2.624 Å and MeO⋯CHO interactions of 2.528–2.584 Å were observed with the O⋯C vector making angles of 105.3–133.7° with the carbonyl bond. The lack of a competing conjugation with the framework for the electrophilic group is a favourable factor compared to the use of peri-naphthalene systems

Synthesis and characterisation of phosphorescent rhenium(I) complexes of hydroxy- and methoxy-substituted imidazo[4,5- f ]-1,10-phenanthroline ligands

Eight new fluorescent ligands (L1-L8) derived from the fused imidazo[4,5-f]-1,10-phenanthroline core, have been synthesised utilising a one-pot methodology. The ligands include two points of structural variety, allowing multiply-substituted aryl groups (including hydroxy and methoxy moieties) to be attached to the ligand core. The ligands L1-L8 are fluorescent (λem = 399–426 nm) and react with pentacarbonylbromorhenium to give coordination complexes of the form fac-[ReBr(CO)3(NˆN)] (where NˆN = L1-L8). The complexes were characterised using a variety of spectroscopic and analytical techniques, including single crystal X-ray diffraction studies on two examples. The rhenium complexes were all found to be luminescent, revealing classical 3MLCT emission at 579–587 nm in aerated solution with corresponding lifetimes in the range 149–166 ns

“Dial Up and Lock In”: Asymmetric organo-Brønsted acid catalysis incorporating stable isotopes

An operationally simple organo-Brønsted-acid-catalyzed asymmetric and regioselective “dial up and lock in” of one or more stable isotopes into organic compounds is unknown. Here, we describe a newly designed, chemically versatile protocol mediating single- or multiple-isotope incorporation into aziridines via a one-pot, three-component, two-step process. By exploiting easy-to-generate isotope-derived starting materials, it allows complete control of isotope positioning, affords >95 atom % isotope incorporation, and generates cis-aziridines with excellent optical activities and regioselectivities. Demonstrating a “low entry point,” and thus easy access to a broad range of researchers, it requires no specialist laboratory equipment and employs readily attainable reaction conditions. Demonstrating their utility, the aziridines are easily transformed into sought-after chiral non-racemic α-amino acids appended with one to three (or more) identical or different isotopes. The widespread use of these compounds ensures that our methodology will be of interest to biological, medicinal, pharmaceutical, agrochemical, biotechnology, materials, and process chemists alike

CO2 as a reaction ingredient for the construction of metal cages:a carbonate-panelled [Gd6Cu3] tridiminished icosahedron

A CO32--panelled [(Gd6Cu3II)-Cu-III] cage conforming to a tridiminished icosahedron is synthesised by bubbling CO2 through a solution of Gd-III and Cu-II ions

5-iodo-4-thio-2′-deoxyuridine: synthesis, structure, and cytotoxic activity

The novel nucleoside 5-iodo-4-thio-2′-deoxyuridine (4) was synthesized and fully characterized by IR, NMR, and MS. Its structure was determined by single-crystal X-ray diffraction. Compound 4 absorbs strongly at 346 nm and is minimally toxic to human tumour cells, but its cytotoxicity is substantially enhanced by low dose UVA radiation. The combined use of 4 and UVA offers a promising route to selectively and effectively kill proliferating cells

Aryl, bi-functionalised imidazo[4,5-f]-1,10-phenanthroline ligands and their luminescent rhenium(I) complexes

Five new imidazo[4,5-f]-1,10-phenanthroline based ligands (1–5) have been synthesised and characterised. The facile synthesis of 1–5 allows two regiochemical points of structural variety allowing highly conjugated and bulky aryl groups of varying functionalities, including azobenzene, trityl and terpyridine constituents, to be attached to the ligand core. 1–5 are fluorescent (λem = 410–415 nm), and react readily with [ReBr(CO)5] in toluene to give neutral coordination complexes of the form fac-[ReBr(CO)3(1–5)]. The series of complexes was characterised using a variety of spectroscopic and analytical techniques. Two examples of this series were characterised in the solid state using single crystal X-ray diffraction which confirmed the octahedral geometry and formulation. Photophysical studies showed that fac-[ReBr(CO)3(1–5)] are phosphorescent in solution under ambient conditions, revealing visible emission (558–585 nm) in aerated solution with corresponding lifetimes in the range 149–267 ns. These attributes are consistent with a triplet metal to ligand charge transfer (3MLCT) emitting state

Efficient NiII2LnIII2 electrocyclization catalysts for the synthesis of trans-4,5-diaminocyclopent-2-enones from 2-furaldehyde and primary or secondary amines

A series of heterometallic coordination clusters (CCs) [NiII2LnIII2(L1)4Cl2(CH3CN)2] 2CH3CN [Ln = Y (1Y), Sm (1Sm), Eu (1Eu), Gd (1Gd), or Tb (1Tb)] were synthesized by the reaction of (E)-2-(2-hydroxy-3-methoxybenzylidene-amino)phenol) (H2L1) with NiCl2·6(H2O) and LnCl3·x(H2O) in the presence of Et3N at room temperature. These air-stable CCs can be obtained in very high yields from commercially available materials and are efficient catalysts for the room-temperature domino ring-opening electrocyclization synthesis of trans-4,5-diaminocyclopent-2-enones from 2-furaldehyde and primary or secondary amines under a non-inert atmosphere. Structural modification of the catalyst to achieve immobilization or photosensitivity is possible without deterioration in catalytic activity