Showing papers by "Georgina M. Rosair published in 2020"

Continuous-flow synthesis and application of polymer-supported BODIPY Photosensitisers for the generation of singlet oxygen; process optimised by in-line NMR spectroscopy

Abstract: Commercial polystyrene Merrifield-type resins have been post-synthetically functionalised with BODIPY photosensitisers via a novel aryl ester linking strategy in continuous-flow. A unique synthetic advantage of post-synthetically modifying heterogeneous materials in flow was identified. The homogeneous analogues of the polymer-supported BODIPYs were synthesised and used as reference to assess photophysical properties altered by the polymer-support and linker. The homogeneous and polymer-supported BODIPYs were applied in visible-light photosensitisation of singlet oxygen for the conversion of α-terpinene to ascaridole. Materials produced in flow were superior to batch in terms of functional loading and photosensitisation efficiency. Flow photochemical reactions generally outperformed batch by a factor of 4 with respect to rate of reaction. The polymer-supported BODIPY resins could be irradiated for 96 h without loss of photosensitising ability. Additional material synthetic modification and conditions optimisation using an in-line NMR spectrometer resulted in a 24-fold rate enhancement from the initial material and conditions.

Unique triple ruthenacarborane cluster

Abstract: Dehalogenation of[1,2-Ph2-3,3-(PPh3)2-3-Cl-closo/pseudocloso-3,1,2-RuC2B9H9]− affords, in addition to the unusual “symbiotic”** cluster [(1,2-Ph2-pseudocloso-3,1,2-RuC2B9H9) (1′,8′-Ph2-closo-2′,1′8′-RuC2B9H9)], a trace amount of a triple cluster species [(1,2-Ph2-pseudocloso-3,1,2-RuC2B9H9)(1′,8′-Ph2-closo-2′,1′,8′-RuC2B9H9)(1″,8″-Ph2-closo-2″,1″,8″-RuC2B9H9)], comprising three (Ph2RuC2B9H9) units linked by η6- coordination of Ph rings to the Ru atoms of the adjacent cluster. The structure of the triple cluster was established by X-ray crystallography, and the potential consequences of its formation are discussed.

Exploration of bis(Nickelation) of 1,1′-bis(o-carborane)

Abstract: The metalation of [Tl]2[1-(1′-3′,1′,2′-closo-TlC2B9H10)-3,1,2-closo-TlC2B9H10], with the smaller {Ni(dmpe)} fragment sourced from [Ni(dmpe)Cl2], is explored. The bis(metalated) products are obtained as a diastereoisomeric mixture. These isomers were separated, fully characterised spectroscopically and crystallographically and identified as rac-[1-(1′-3′-(dmpe)-3′,1′,2′-closo-NiC2B9H10)-3-(dmpe)-3,1,2-closo-NiC2B9H10] (1) and meso-[1-(1′-3′-(dmpe)-3′,1′,2′-closo-NiC2B9H10)-3-(dmpe)-3,1,2-closo-NiC2B9H10] (2). Previously, these 3,1,2-NiC2B9-3′,1′,2′-NiC2B9 architectures (where both cages are not isomerised), were inaccessible, and thus new structures can be achieved during bis(nickelation) with {Ni(dmpe)}. Further, the metalation of the tetra-thallium salt with the bulky {Ni(dppe)} fragment sourced from [Ni(dppe)Cl2] was also studied. These bis(nickelated) products were also fully characterised and are afforded as the stereospecific species rac-[1-(1′-3′-(dppe)-3′,1′,2′-closo-NiC2B9H10)-3-(dppe)-3,1,2-closo-NiC2B9H10] (3) and [1-(2′-4′-(dppe)-4′,1′,2′-closo-NiC2B9H10)-3-(dppe)-3,1,2-closo-NiC2B9H10] (4α). In the latter metalation, compound 3 shows intramolecular dihydrogen bonding, contributing to the stereospecificity, whereas isomerisation from 3,1,2 to 4,1,2- in the 4α is related to steric relief.

Crystal structure and Hirshfeld surface analysis of one-dimensional copper(II) coordination polymer incorporating succinate and tetra-methyl-ethylene-diamine ligands.

Abstract: The reaction of copper nitrate with succinic acid (succH) and N,N,N′,N′-tetra­methyl­ethylenedi­amine (TMEDA) in basic solution produces the complex catena-poly[[[(N,N,N′,N′-tetra­methyl­ethylenedi­amine-κ2N,N′)copper(II)]-μ-succinato-κ2O1:O4] tetra­hydrate], {[Cu(C4H4O4)(C6H16N2)]·4H2O}n or {[Cu(succ)(tmeda)]·4H2O}n. Each carboxyl­ate group of the succinate ligand coordinates to a CuII atom in a monodentate fashion, giving rise to a distorted square-planar geometry. The succinate ligands bridge the CuII centres, forming one-dimensional polymeric chains. Hydrogen bonds between the ligands and water mol­ecules link these chains into sheets that lie parallel to the ac plane. Hirshfeld surface analysis, dnorm and two-dimensional fingerprint plots were examined to verify the contributions of the different inter­molecular contacts within the supra­molecular structure.

Crystal structure and Hirshfeld surface analysis of a copper(II) complex with ethyl­enedi­amine and non-coordinated benzoate

Abstract: In the title compound, di­aqua­bis­(ethyl­enedi­amine-κ2N,N′)copper(II) bis­(2-nitro­benzoate), [Cu(C2H8N2)2(H2O)2](C7H4NO4)2, two di­aqua­bis­(ethyl­enedi­amine)­copper(II) cations and four nitro­benzoate anions are present in the asymmetric unit. All four anions are `whole-mol­ecule' disordered over two sets of sites. The major components have refined occupancies of 0.572 (13), 0.591 (9), 0.601 (9) and 0.794 (10). The CuII ions exhibit slightly distorted octa­hedral geometries. In the crystal, cations and anions are connected to each other via N—H⋯O and O—H⋯O hydrogen bonds, forming a two-dimensional network parallel to (200). The inter­molecular contacts in the crystal were further analysed using Hirshfeld surface analysis, which indicates that the most significant contacts are O⋯H/H⋯O (42.9%), followed by H⋯H (35.7%), C⋯H/H⋯C (14.2%), C⋯C (2.9%), C⋯O/O⋯C (2.2%), N⋯H/H⋯N (0.9%) and N⋯O/O⋯N (0.3%).