TY - JOUR
T1 - Dinuclear Au(i) N-heterocyclic carbene complexes derived from unsymmetrical azolium cyclophane salts
T2 - Potential probes for live cell imaging applications
AU - Wedlock, Louise E.
AU - Barnard, Peter J.
AU - Filipovska, Aleksandra
AU - Skelton, Brian W.
AU - Berners-Price, Susan J.
AU - Baker, Murray V.
PY - 2016/8/14
Y1 - 2016/8/14
N2 - We have synthesized a new series of azolium cyclophanes and used them as precursors of inherently luminescent dinuclear Au(i)-N-heterocyclic carbene (NHC) complexes. The azolium cyclophanes contained two azolium groups (either imidazolium or benzimidazolium), an o-xylyl group, and an alkyl linker chain (either C2, C3 or C4). All of the azolium cyclophanes were characterised by X-ray diffraction studies and VT NMR studies, and all were fluxional in solution on the NMR timescale. The C3- and C4-linked azolium cyclophanes served as precursors of Au2L2 2+ complexes (L is a cyclophane bis(NHC) ligand). Due to the unsymmetrical nature of the azolium cyclophanes, the Au2L2 2+ complexes each existed as cis and trans isomers. X-ray diffraction studies showed that the Au2L2 2+ complexes had short intramolecular Au⋯Au distances, in the range 2.9-3.3 Å, suggestive of an aurophilic attraction, presumably as a consequence of the geometrical constraints imposed by the cyclophane bis(NHC) ligands. The complexes having the shortest Au⋯Au distances (i.e., those based on C3-linked cyclophanes) exhibited intense luminescence in solution. The uptake of one of the dinuclear Au-NHC complexes by tumorigenic cells, and its subsequent distribution and toxicity in the cells, was monitored by luminescence microscopy over 6 h and proliferation measurements, respectively.
AB - We have synthesized a new series of azolium cyclophanes and used them as precursors of inherently luminescent dinuclear Au(i)-N-heterocyclic carbene (NHC) complexes. The azolium cyclophanes contained two azolium groups (either imidazolium or benzimidazolium), an o-xylyl group, and an alkyl linker chain (either C2, C3 or C4). All of the azolium cyclophanes were characterised by X-ray diffraction studies and VT NMR studies, and all were fluxional in solution on the NMR timescale. The C3- and C4-linked azolium cyclophanes served as precursors of Au2L2 2+ complexes (L is a cyclophane bis(NHC) ligand). Due to the unsymmetrical nature of the azolium cyclophanes, the Au2L2 2+ complexes each existed as cis and trans isomers. X-ray diffraction studies showed that the Au2L2 2+ complexes had short intramolecular Au⋯Au distances, in the range 2.9-3.3 Å, suggestive of an aurophilic attraction, presumably as a consequence of the geometrical constraints imposed by the cyclophane bis(NHC) ligands. The complexes having the shortest Au⋯Au distances (i.e., those based on C3-linked cyclophanes) exhibited intense luminescence in solution. The uptake of one of the dinuclear Au-NHC complexes by tumorigenic cells, and its subsequent distribution and toxicity in the cells, was monitored by luminescence microscopy over 6 h and proliferation measurements, respectively.
UR - http://www.scopus.com/inward/record.url?scp=84979924749&partnerID=8YFLogxK
U2 - 10.1039/c6dt01409g
DO - 10.1039/c6dt01409g
M3 - Article
C2 - 27426282
AN - SCOPUS:84979924749
VL - 45
SP - 12221
EP - 12236
JO - Dalton Transactions
JF - Dalton Transactions
SN - 1477-9234
IS - 30
ER -