TY  - JOUR
AU  - Schmitz, Sebastian
AU  - Qiu, Xinkai
AU  - Glöß, Maria
AU  - van Leusen, Jan
AU  - Izarova, Natalya V.
AU  - Nadeem, Muhammad Arif
AU  - Griebel, Jan
AU  - Chiechi, Ryan C.
AU  - Kögerler, Paul
AU  - Monakhov, Kirill Yu.
TI  - Conductive Self-Assembled Monolayers of Paramagnetic {CoIICo4III} and {Co4IICo2III} Coordination Clusters on Gold Surfaces
JO  - Frontiers in Chemistry
VL  - 7
SN  - 2296-2646
CY  - Lausanne
PB  - Frontiers Media
M1  - FZJ-2020-00805
SP  - 681
PY  - 2019
AB  - Two polynuclear cobalt(II,III) complexes, [Co5(N3)4(N-n-bda)4(bza·SMe)2] (1) and [Co6(N3)4(N-n-bda)2(bza·SMe)5(MeOH)4]Cl (2), where Hbza·SMe = 4-(methylthio)benzoic acid and N-n-H2bda = N-n-butyldiethanolamine, were synthesized and fully characterized by various techniques. Compound 1 exhibits an unusual, approximately C2-symmetric {CoIICoIII4} core of two isosceles Co3 triangles with perpendicularly oriented planes, sharing a central, high-spin CoII ion residing in a distorted tetrahedral coordination environment. This central CoII ion is connected to four outer, octahedrally coordinated low-spin CoIII ions via oxo bridges. Compound 2 comprises a semi-circular {CoII4CoIII2} motif of four non-interacting high-spin CoII and two low-spin CoIII centers in octahedral coordination environments. Self-assembled monolayers (SAMs) of 1 and 2 were physisorbed on template-stripped gold surfaces contacted by an eutectic gallium-indium (EGaIn) tip. The acquired current density-voltage (I-V) data revealed that the cobalt-based SAMs are more electrically robust than those of the previously reported dinuclear {CuIILnIII} complexes with Ln = Gd, Tb, Dy, or Y (Schmitz et al., 2018a). In addition, between 170 and 220°C, the neutral, mixed-valence compound 1 undergoes a redox modification, yielding a {Co5}-based coordination cluster (1-A) with five non-interacting, high-spin octahedral CoII centers as indicated by SQUID magnetometry analysis in combination with X-ray photoelectron spectroscopy and infrared spectroscopy. Solvothermal treatment of 1 results in a high-nuclearity coordination cluster, [Co10(N3)2(N-n-bda)6(bza·SMe)6] (3), containing 10 virtually non-interacting high-spin CoII centers.
LB  - PUB:(DE-HGF)16
C6  - pmid:31750287
UR  - <Go to ISI:>//WOS:000502093700001
DO  - DOI:10.3389/fchem.2019.00681
UR  - https://juser.fz-juelich.de/record/873537
ER  -