Two new alkali vanadate carbonates with divalent transition metals have been synthesized as large single crystals via a hightemperature (600 °C) hydrothermal technique. Compound I , Rb 2 Mn 3 (VO 4 ) 2 CO 3 , crystallizes in the trigonal crystal system in the space group P 3̄1 c , and compound II , K 2 Co 3 (VO 4 ) 2 CO 3 , crystallizes in the hexagonal space group P 6 3 / m . Both structures contain honeycomb layers and triangular lattices made from edgesharing MO 6 octahedra and MO 5 trigonal bipyramids, respectively. The honeycomb and triangular layers are connected along the c axis through tetrahedral [VO 4 ] groups. The MO 5 units are connected with each other by carbonate groups in the ab plane by forming a triangular magnetic lattice. The difference in space groups between I and II was also investigated with Density Functional Theory (DFT) calculations. Single crystal magnetic characterization of I indicates three magnetic transitions at 77 K, 2.3 K, and 1.5 K. The corresponding magnetic structures for each magnetic transition of I were determined using single crystal neutron diffraction. At 77 K the compound orders in the MnO 6more »
Excitonically Coupled Cyclic BF _{2} Arrays of Calix[8]‐ and Calix[16]phyrin as Near‐IR‐Chromophores
Two giant calix[n]phyrin derivatives namely calix
[8] (4) and calix[16]phyrin (5), involving two and four BF2
units, respectively, were prepared through the condensation of
the bisnaphthobipyrrolylmetheneBF2 complex (3) with pentafluorobenzaldehyde.
Calix[n]phyrins 4 and 5 display extremely
high extinction coefficients (3.67 and 4.82
105m1cm1, respectively) in the nearIR region, which was
taken as initial evidence for strong excitonic coupling within
these cyclic multichromophoric systems. Detailed insights into
the effect of excitonic coupling dynamics on the electronic
structure and photophysical properties of the macrocycles
came from fluorescence, timecorrelated singlephoton counting
(TCSPC) and transient absorption (TA) measurements.
Support for these experimental findings came from theoretical
studies. Theory and experiment confirmed that the coupling
between the excitons depends on the specifics of the calix
[n]phyrin structure, not just its size.
 Award ID(s):
 1807152
 Publication Date:
 NSFPAR ID:
 10170731
 Journal Name:
 Angewandte Chemie International Edition
 Volume:
 59
 Page Range or eLocationID:
 2–10
 ISSN:
 14337851
 Sponsoring Org:
 National Science Foundation
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