Rhodamine 6G-Labeled Pyridyl Aroylhydrazone Fe(II) Complex Exhibiting Synergetic Spin Crossover and Fluorescence

Here, we use a pyridinecarbaldehyde rhodamine 6G hydrazone ligand (L) to synthesize an Fe­(II) complex <b>1</b> for the search of new fluorescent-spin crossover (SCO) materials. Single-crystal structural determinations suggest that the Fe­(II) ion is chelated by two ring-opened ligands (L-o) to form a FeN₄O₂ coordination environment, and intermolecular π---π contacts of the xanthene groups connect the adjacent molecules to form a supramolecular one-dimensional chain. Magnetic susceptibility measurements on complex <b>1</b> show that three-step SCO takes place in the temperature range of 120–350 K, and its desolvated form <b>1-d</b> exhibits SCO around room temperature (<i>T</i>_c↑ = 343 K and <i>T</i>_c↓ = 303 K) with a wide hysteresis loop of 40 K. Moreover, complex <b>1-d</b> displays light-induced excited spin-state trapping phenomenon. Intriguingly, the fluorescence intensity of the maximum emission at 560 nm for complex <b>1-d</b> displays discontinuous variation in the range of 250–400 K, indicative of the occurrence of synergetic fluorescence and SCO

Rhodamine 6G-Labeled Pyridyl Aroylhydrazone Fe(II) Complex Exhibiting Synergetic Spin Crossover and Fluorescence

Here, we use a pyridinecarbaldehyde rhodamine 6G hydrazone ligand (L) to synthesize an Fe­(II) complex <b>1</b> for the search of new fluorescent-spin crossover (SCO) materials. Single-crystal structural determinations suggest that the Fe­(II) ion is chelated by two ring-opened ligands (L-o) to form a FeN₄O₂ coordination environment, and intermolecular π---π contacts of the xanthene groups connect the adjacent molecules to form a supramolecular one-dimensional chain. Magnetic susceptibility measurements on complex <b>1</b> show that three-step SCO takes place in the temperature range of 120–350 K, and its desolvated form <b>1-d</b> exhibits SCO around room temperature (<i>T</i>_c↑ = 343 K and <i>T</i>_c↓ = 303 K) with a wide hysteresis loop of 40 K. Moreover, complex <b>1-d</b> displays light-induced excited spin-state trapping phenomenon. Intriguingly, the fluorescence intensity of the maximum emission at 560 nm for complex <b>1-d</b> displays discontinuous variation in the range of 250–400 K, indicative of the occurrence of synergetic fluorescence and SCO

Rhodamine 6G-Labeled Pyridyl Aroylhydrazone Fe(II) Complex Exhibiting Synergetic Spin Crossover and Fluorescence

Here, we use a pyridinecarbaldehyde rhodamine 6G hydrazone ligand (L) to synthesize an Fe­(II) complex <b>1</b> for the search of new fluorescent-spin crossover (SCO) materials. Single-crystal structural determinations suggest that the Fe­(II) ion is chelated by two ring-opened ligands (L-o) to form a FeN₄O₂ coordination environment, and intermolecular π---π contacts of the xanthene groups connect the adjacent molecules to form a supramolecular one-dimensional chain. Magnetic susceptibility measurements on complex <b>1</b> show that three-step SCO takes place in the temperature range of 120–350 K, and its desolvated form <b>1-d</b> exhibits SCO around room temperature (<i>T</i>_c↑ = 343 K and <i>T</i>_c↓ = 303 K) with a wide hysteresis loop of 40 K. Moreover, complex <b>1-d</b> displays light-induced excited spin-state trapping phenomenon. Intriguingly, the fluorescence intensity of the maximum emission at 560 nm for complex <b>1-d</b> displays discontinuous variation in the range of 250–400 K, indicative of the occurrence of synergetic fluorescence and SCO

Rhodamine 6G-Labeled Pyridyl Aroylhydrazone Fe(II) Complex Exhibiting Synergetic Spin Crossover and Fluorescence

Here, we use a pyridinecarbaldehyde rhodamine 6G hydrazone ligand (L) to synthesize an Fe­(II) complex <b>1</b> for the search of new fluorescent-spin crossover (SCO) materials. Single-crystal structural determinations suggest that the Fe­(II) ion is chelated by two ring-opened ligands (L-o) to form a FeN₄O₂ coordination environment, and intermolecular π---π contacts of the xanthene groups connect the adjacent molecules to form a supramolecular one-dimensional chain. Magnetic susceptibility measurements on complex <b>1</b> show that three-step SCO takes place in the temperature range of 120–350 K, and its desolvated form <b>1-d</b> exhibits SCO around room temperature (<i>T</i>_c↑ = 343 K and <i>T</i>_c↓ = 303 K) with a wide hysteresis loop of 40 K. Moreover, complex <b>1-d</b> displays light-induced excited spin-state trapping phenomenon. Intriguingly, the fluorescence intensity of the maximum emission at 560 nm for complex <b>1-d</b> displays discontinuous variation in the range of 250–400 K, indicative of the occurrence of synergetic fluorescence and SCO

Rhodamine 6G-Labeled Pyridyl Aroylhydrazone Fe(II) Complex Exhibiting Synergetic Spin Crossover and Fluorescence

Here, we use a pyridinecarbaldehyde rhodamine 6G hydrazone ligand (L) to synthesize an Fe­(II) complex <b>1</b> for the search of new fluorescent-spin crossover (SCO) materials. Single-crystal structural determinations suggest that the Fe­(II) ion is chelated by two ring-opened ligands (L-o) to form a FeN₄O₂ coordination environment, and intermolecular π---π contacts of the xanthene groups connect the adjacent molecules to form a supramolecular one-dimensional chain. Magnetic susceptibility measurements on complex <b>1</b> show that three-step SCO takes place in the temperature range of 120–350 K, and its desolvated form <b>1-d</b> exhibits SCO around room temperature (<i>T</i>_c↑ = 343 K and <i>T</i>_c↓ = 303 K) with a wide hysteresis loop of 40 K. Moreover, complex <b>1-d</b> displays light-induced excited spin-state trapping phenomenon. Intriguingly, the fluorescence intensity of the maximum emission at 560 nm for complex <b>1-d</b> displays discontinuous variation in the range of 250–400 K, indicative of the occurrence of synergetic fluorescence and SCO

Rhodamine Salicylaldehyde Hydrazone Dy(III) Complexes: Fluorescence and Magnetism

Three new dysprosium­(III) complexes [Dy₂(HL¹-o)₂(L¹)­(NO₃)₃]­[Dy­(NO₃)₅]·1.5ACE·0.5Et₂O (<b>1</b>), [Dy­(L¹)₃]·2.5MeOH·MeCN (<b>2</b>), and [Dy­(L²)₃]·MeOH·MeCN (<b>3</b>) (HL¹ = rhodamine B salicylaldehyde hydrazine, HL² = rhodamine B 3-methylsalicylaldehyde hydrazine) were synthesized and characterized. Purple complex <b>1</b> contains two ring-open ligands HL¹-o and shows fluorescence of the rhodamine amide moiety, whereas yellow complexes <b>2</b> and <b>3</b> are comprised of ring-close ligands (L^1/2)⁻ and display fluorescence of the salicylaldehyde Schiff base part. For <b>2</b> and <b>3</b>, Dy­(III) ions are nine coordinated by the six oxygen and three nitrogen atoms of three chelate (L^1/2)⁻ ligands, but the arrangements of the three ligands are different owing to the methyl substituent on HL². There are three short predominant Dy–O_phenoxy bonds in <b>2</b> and <b>3</b>. The largest O_phenoxy–Dy–O_phenoxy angle is 148.64(17)° for <b>2</b> and 89.63(13)° for <b>3</b>. Magnetic studies reveal that complex <b>2</b> is a field-induced single-molecule magnet (<i>U</i>_eff = 104.2 K under a dc magnetic field of 2000 Oe), and <b>3</b> exhibits only a magnetic relaxation behavior owing to the quantum tunneling of magnetization (QTM). Furthermore, ab initio calculations illustrate that the disposition of predominant Dy–O_phenoxy bonds affects the magnetic anisotropy of the Dy­(III) ions and relaxation processes of complexes <b>2</b> and <b>3</b>