Coexistence of luminescence and spin-crossover in 2D iron(ii) Hofmann clathrates modulated through guest encapsulation

Abstract

The search for advanced multifunctional materials displaying two or more simultaneous and correlated physicochemical properties represents a key step in developing further practical applications. In this context, here we report...

Multifunctionality of luminescent molecular nanomagnets based on lanthanide complexes

“…101,102 This idea was inspired by research on heterometallic d-d or d-f coordination assemblies built using polycyanidometallates, which are attractive molecular platforms for multifunctional materials that link magnetic phenomena, e.g., spin transitions, magnetic ordering, or single-molecule magnetism, with other physical properties. [103][104][105][106][107][108][109] Both luminescent materials built from Ln(III) complexes and 4f-metal-based SMMs have been independently explored as the source of multifunctionality. The Ln(III) complexes were found to combine luminescent effects with second harmonic generation (SHG), [110][111][112] proton or electronic conductivity, 113,114 and catalytic activity, 115,116 as well as sensitivity to solvent molecules, [117][118][119] various chemicals, [120][121][122] and light.…”

“…This occurs since many photoswitchable organic ligands, as well as metal complexes, e.g., spin-crossover-active Fe(II) and Mn(III) centers, and pairs of metal complexes that show photoinduced electron transfer, e.g., cyanido-bridged Co(II) and W(V) or Co(II) and Fe(III) centers, are strongly coloured, which limits their emission properties. 103,104,107,109 Moreover, the light must be used to switch the state of the system, and it must be ensured that light of a different wavelength simultaneously induces luminescence without changing the state of the material. A few research groups have addressed this challenge using luminescent Ln-SMMs.…”

Broad-range spin-crossover modulation in guest-responsive 2D Hofmann-type coordination polymers

“…A recent example highlighting this strategy involves the functionalization of the axial pyridine with an anthracene fluorescent agent affording the compounds {Fe(AnPy) 2 [M(CN) 2 ] 2 } (AnPy = 9-anthracenepyridine, M = Au, Ag) which display luminescence coupled to SCO. 29 Recently, we reported a new family of 2D HCPs formulated as {Fe(5-NH 2 Pym) 2 [M(CN) 4 ]}•xguest (1(NH 2 ) M •xguest; 5-NH 2 Pym = 5-aminopyrimidine; M = Pd II , Pt II ; guest = H 2 O, MeOH, EtOH; x = 0-1) in which the amino group was introduced for synergistic modulation of SCO with the uptake of guests by single crystal to single crystal transformation. 30 The interplay between SCO and host-guest chemistry in 1 (NH 2 ) M •xguest encouraged us to investigate the influence of pyrimidine functionalization on tailoring the SCO in isostructural {Fe(5-OHPym) 2 [M(CN) 4 ]}•xguest frameworks (1 (OH) M •xguest, M = Pt, Pd; guest = H 2 O, MeOH, EtOH; x = 0-1), prepared by substitution of 5-NH 2 Pym with 5-OHPym (5-hydroxypyrimidine) (Scheme 1), which was selected to enhance the host-guest interactions.…”

“…A recent example highlighting this strategy involves the functionalization of the axial pyridine with an anthracene fluorescent agent affording the compounds {Fe(AnPy) 2 [M(CN) 2 ] 2 } (AnPy = 9-anthracenepyridine, M = Au, Ag) which display luminescence coupled to SCO. 29…”

Synergetic Spin-Crossover and Luminescent Properties in a Multifunctional 2D Iron(II) Coordination Polymer

“…Therefore, it is still a challenge to realize the synergistic effect between SCO and fluorescence. In the reported materials, there are relatively few 2D ,,, and 3D − , luminescent SCO systems because of the difficulty of the synthetic technology. Therefore, the synthesis of stable multidimensional materials showing a correlation between SCO and luminescence is extremely important.…”