Structural and spectroscopic properties of trans-difluoro(1,4,8,12-tetraazacyclopentadecane)chromium(III) perchlorate hydrate

Crystal structure oftrans-difluoridotetrakis(pyridine-κN)chromium(III) trichlorido(pyridine-κN)zincate monohydrate from synchrotron data

“…These Cr-N(py) and Cr-F bond lengths are in good agreement with those observed in trans- (Fochi et al, 1991;Moon & Choi, 2013;Moon et al, 2014;Birk et al, 2010). The Cr-F bond lengths are also similar to the values found in trans-[Cr(15aneN 4 )F 2 ]ClO 4 (15aneN 4 = 1,4,8,12-tetraazacyclopentadecane) and trans-[Cr(2,2,3-tet)F 2 ]ClO 4 (2,2,3-tet = 1,4,7,11-tetraazaundecane) (Choi et al, 2006;. However, the Cr-F bond lengths are somewhat shorter than those found for bridging fluorides [1.9045 (14)-1.9145 (14) Å ; Dreiser et al, 2012).…”

“…Octahedral Cr III complexes and their 3d-4f clusters containing lanthanides revealing paramagnetic features are of great importance for the development of new molecule-based magnets and solid-state laser materials (Powell, 1998;Dreiser et al, 2012;Singh et al, 2013). We are therefore interested in the preparation, crystal structures and spectroscopic properties of chromium(III) complexes containing mixed various ligands (Choi, 2000a,b;Choi et al, 2004Choi et al, , 2006).…”

Correction to Photochemistry of trans-Cr(cyclam)(ONO)2+, a Nitric Oxide Precursor

“…In these contexts, we recalculated the structure by replacing the putative oxides by fluorides and found that the final R indices [ I > 2σ( I )] improved from R1 = 0.0668 and wR2 = 0.1960 to R1 = 0.0595 and wR2 = 0.1716 (details are shown in the Supporting Information). Furthermore, the newly calculated structure gives Cr–F bonds nearly identical with those reported for the analogous trans -[Cr([15]aneN 4 )F 2 ](ClO 4 )·H 2 O ([15]aneN 4 = 1,4,8,12-tetraazacyclopentadecane) . In this context, we conclude that the structure reported in Figure 5 and refined in the attached Supporting Information is indeed that of trans -[Cr(cyclam)F 2 ](ClO 4 )·H 2 O.…”

“…Furthermore, the newly calculated structure gives CrÀF bonds nearly identical with those reported for the analogous trans-[Cr ([15]aneN 4 )F 2 ](ClO 4 ) 3 H 2 O ([15]aneN 4 = 1,4, 8,12-tetraazacyclopentadecane). 1 In this context, we conclude that the structure reported in Figure 5 and refined in the attached Supporting Information is indeed that of trans-[Cr(cyclam)…”

Synthesis, Spectroscopic and Ligand Field Properties of trans-Difluorobis(2,2-dimethylpropane-1,3-diamine)chromium(III) Perchlorate

“…The assignment of geometrical configuration is also suggested by inspection of the d-d absorption spectra. 16,17 The position of the spin-allowed transitions in the electronic spectra, the number of bands, and their coefficients are usually reliable indicators for distinguishing the cis and trans geometrical isomers. The more symmetrical trans chromium(III) complexes with two fluoro and Me 2 tn ligands have four symmetric bands in the visible region, and these bands are located at higher wavelengths and have lower extinction coefficients than those of less symmetrical cis-isomers.…”