Coordination Cluster Nuclearity Decreases with Decreasing Rare Earth Ionic Radius in 1:1 Cr/Ln <i>N</i>‑Butyldiethanolamine Compounds: A Journey across the Lanthanide Series from Cr₄^IIILa₄–Cr₄^IIITb₄ via Cr₃^IIIDy₃ and Cr₃^IIIHo₃ to Cr₂^IIIEr₂–Cr₂^IIILu₂

Reactions of the <i>N</i>-substituted diethanolamine ligand <i>N</i>-<i>n</i>-butyldiethanolamine with chromium­(II) and lanthanide­(III)/rare earth salts (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y) in the presence of coligands give access to three series of isostructural 1:1 3d­(Cr^III)/4f­(Ln^III) coordination cluster compounds that can be designated in terms of octanuclear “square-in-square” (Ln = La–Tb), hexanuclear “triangle-in-triangle” (Ln = Dy, Ho, Y) and tetranuclear “butterfly” or defect dicubane core (Ln = Er–Lu) topologies as revealed by single-crystal X-ray crystallographic analysis. The bulk magnetic properties were also measured. The influences of the various components in the reaction system on the final topology and the role of the ionic radius are discussed

Coordination Cluster Nuclearity Decreases with Decreasing Rare Earth Ionic Radius in 1:1 Cr/Ln <i>N</i>‑Butyldiethanolamine Compounds: A Journey across the Lanthanide Series from Cr₄^IIILa₄–Cr₄^IIITb₄ via Cr₃^IIIDy₃ and Cr₃^IIIHo₃ to Cr₂^IIIEr₂–Cr₂^IIILu₂

Reactions of the <i>N</i>-substituted diethanolamine ligand <i>N</i>-<i>n</i>-butyldiethanolamine with chromium­(II) and lanthanide­(III)/rare earth salts (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y) in the presence of coligands give access to three series of isostructural 1:1 3d­(Cr^III)/4f­(Ln^III) coordination cluster compounds that can be designated in terms of octanuclear “square-in-square” (Ln = La–Tb), hexanuclear “triangle-in-triangle” (Ln = Dy, Ho, Y) and tetranuclear “butterfly” or defect dicubane core (Ln = Er–Lu) topologies as revealed by single-crystal X-ray crystallographic analysis. The bulk magnetic properties were also measured. The influences of the various components in the reaction system on the final topology and the role of the ionic radius are discussed

Structures, Magnetic Properties, and Photoluminescence of Dicarboxylate Coordination Polymers of Mn, Co, Ni, Cu Having <i>N</i>‑(4-Pyridylmethyl)-1,8-naphthalimide

Supramolecular interactions of <i>N</i>-(4-pyridylmethyl)-1,8-naphthalimide (<b>L</b>) and flexibility of intervening units of dicarboxylate ligands contribute to formation of different types of coordination polymers such as [Mn<b>L</b>₂(Adp)­(H₂O)₂]_<i>n</i>·2<i>n</i>H₂O (<b>1</b>), [Co<b>L</b>₂(Fum)­(H₂O)₂]_<i>n</i>·2<i>n</i>H₂O (<b>2</b>), [Co<b>L</b>₂(Adp)­(H₂O)₂]<i>_n</i>·2<i>n</i>H₂O (<b>3</b>), [Ni<b>L</b>(Fum)­(H₂O)₃]<i>_n</i>·H₂O (<b>4</b>), [Cu<b>L</b>₂(Fum)]<i>_n</i>·<i>n</i>H₂O (<b>5</b>), [Cu<b>L</b>(Mal)]_<i>n</i> (<b>6</b>), and [Cu₃<b>L</b>₆(Adp)₃(H₂O)₃]<i>_n</i> (<b>7</b>) (where Adp = adipate, Fum = fumarate, and Mal = malonate). These coordination polymers are structurally characterized. Coordination polymers <b>1</b> and <b>3</b> are isostructural having three-dimensional (3D) supramolecular layer-like structures. Coordination polymer <b>2</b> forms a two-dimensional (2D) supramolecular network through C–H···π and O···π interactions. Coordination polymer <b>4</b> forms H-bonded 3D chainlike supramolecular architecture. Coordination polymer <b>5</b> forms a 3D supramolecular sheet-like structure, whereas coordination polymer <b>6</b> and coordination polymer <b>7</b> forms a 2D lamellar structure through π···π and C–H···π interactions. Manganese coordination polymer <b>1</b> shows weak antiferromagnetic interactions between chains at low temperature and also exhibits single chain magnetic behavior. Coordination polymers <b>2</b> and <b>3</b> show saturation value of magnetic moment at 2 K and 7 T, which are lower than the spin-only Co­(II) ion. Coordination polymer <b>4</b> show spin-only values for Ni­(II) ion. The room-temperature χ_M<i>T</i> value for coordination polymer <b>5</b> is close to the spin-only value for two Cu­(II) ions. With lowering of the temperature, the χ_M<i>T</i> value remains constant to 35 K, from where the value begins to decrease to a minimum at 2 K. For copper coordination polymer <b>6</b> value of χ_M<i>T</i> smoothly decreases with lowering of the temperature to attain a quasi plateau between 80 K and 35 K, and it further sharply increases at 2 K. Coordination polymer <b>7</b> shows spin-only Cu­(II) ion. These coordination polymers in solid state show quenching of fluorescence emission of ligand <b>L</b>, as well as a shift of emission toward a shorter wavelength

Butterfly M₂^IIIEr₂ (M^III = Fe and Al) SMMs: Synthesis, Characterization, and Magnetic Properties

The reaction of <i>N</i>-(2-pyridylmethyl)­iminodiethanol (H₂L, pmide), FeCl₂·4H₂O or AlCl₃·6H₂O with ErCl₃·6H₂O and <i>p</i>-Me-PhCO₂H in the ratio of 2:1:1:4 in the presence of Et₃N in MeOH and MeCN yielded compounds [Fe₂Er₂(μ₃-OH)₂(pmide)₂(<i>p</i>-Me-PhCO₂)₆]·2MeCN (<b>1</b>) and [Al₂Er₂(μ₃-OH)₂(pmide)₂(<i>p</i>-Me-PhCO₂)₆]·2MeCN (<b>2</b>). These two complexes are isostructural, possessing a planar butterfly motif with the Er^III ions in the wingtip positions. Both compounds show single molecule magnet (SMM) behavior. For the [Al₂Er₂] compound, the slow relaxation of the magnetization under zero applied direct current (dc) field does not show maxima, but the relaxation processes could be analyzed using an applied dc field of 1000 Oe. In-depth alternating current measurements under different dc fields on the [Fe₂Er₂] compound reveals that the Fe–Fe and Fe–Er interactions speed up the relaxation and decrease the energy barrier height of the SMM in comparison with the [Al₂Er₂] case

Butterfly M₂^IIIEr₂ (M^III = Fe and Al) SMMs: Synthesis, Characterization, and Magnetic Properties

The reaction of <i>N</i>-(2-pyridylmethyl)­iminodiethanol (H₂L, pmide), FeCl₂·4H₂O or AlCl₃·6H₂O with ErCl₃·6H₂O and <i>p</i>-Me-PhCO₂H in the ratio of 2:1:1:4 in the presence of Et₃N in MeOH and MeCN yielded compounds [Fe₂Er₂(μ₃-OH)₂(pmide)₂(<i>p</i>-Me-PhCO₂)₆]·2MeCN (<b>1</b>) and [Al₂Er₂(μ₃-OH)₂(pmide)₂(<i>p</i>-Me-PhCO₂)₆]·2MeCN (<b>2</b>). These two complexes are isostructural, possessing a planar butterfly motif with the Er^III ions in the wingtip positions. Both compounds show single molecule magnet (SMM) behavior. For the [Al₂Er₂] compound, the slow relaxation of the magnetization under zero applied direct current (dc) field does not show maxima, but the relaxation processes could be analyzed using an applied dc field of 1000 Oe. In-depth alternating current measurements under different dc fields on the [Fe₂Er₂] compound reveals that the Fe–Fe and Fe–Er interactions speed up the relaxation and decrease the energy barrier height of the SMM in comparison with the [Al₂Er₂] case

Butterfly M₂^IIIEr₂ (M^III = Fe and Al) SMMs: Synthesis, Characterization, and Magnetic Properties

The reaction of <i>N</i>-(2-pyridylmethyl)­iminodiethanol (H₂L, pmide), FeCl₂·4H₂O or AlCl₃·6H₂O with ErCl₃·6H₂O and <i>p</i>-Me-PhCO₂H in the ratio of 2:1:1:4 in the presence of Et₃N in MeOH and MeCN yielded compounds [Fe₂Er₂(μ₃-OH)₂(pmide)₂(<i>p</i>-Me-PhCO₂)₆]·2MeCN (<b>1</b>) and [Al₂Er₂(μ₃-OH)₂(pmide)₂(<i>p</i>-Me-PhCO₂)₆]·2MeCN (<b>2</b>). These two complexes are isostructural, possessing a planar butterfly motif with the Er^III ions in the wingtip positions. Both compounds show single molecule magnet (SMM) behavior. For the [Al₂Er₂] compound, the slow relaxation of the magnetization under zero applied direct current (dc) field does not show maxima, but the relaxation processes could be analyzed using an applied dc field of 1000 Oe. In-depth alternating current measurements under different dc fields on the [Fe₂Er₂] compound reveals that the Fe–Fe and Fe–Er interactions speed up the relaxation and decrease the energy barrier height of the SMM in comparison with the [Al₂Er₂] case

Structures, Magnetic Properties, and Photoluminescence of Dicarboxylate Coordination Polymers of Mn, Co, Ni, Cu Having <i>N</i>‑(4-Pyridylmethyl)-1,8-naphthalimide

Supramolecular interactions of <i>N</i>-(4-pyridylmethyl)-1,8-naphthalimide (<b>L</b>) and flexibility of intervening units of dicarboxylate ligands contribute to formation of different types of coordination polymers such as [Mn<b>L</b>₂(Adp)­(H₂O)₂]_<i>n</i>·2<i>n</i>H₂O (<b>1</b>), [Co<b>L</b>₂(Fum)­(H₂O)₂]_<i>n</i>·2<i>n</i>H₂O (<b>2</b>), [Co<b>L</b>₂(Adp)­(H₂O)₂]<i>_n</i>·2<i>n</i>H₂O (<b>3</b>), [Ni<b>L</b>(Fum)­(H₂O)₃]<i>_n</i>·H₂O (<b>4</b>), [Cu<b>L</b>₂(Fum)]<i>_n</i>·<i>n</i>H₂O (<b>5</b>), [Cu<b>L</b>(Mal)]_<i>n</i> (<b>6</b>), and [Cu₃<b>L</b>₆(Adp)₃(H₂O)₃]<i>_n</i> (<b>7</b>) (where Adp = adipate, Fum = fumarate, and Mal = malonate). These coordination polymers are structurally characterized. Coordination polymers <b>1</b> and <b>3</b> are isostructural having three-dimensional (3D) supramolecular layer-like structures. Coordination polymer <b>2</b> forms a two-dimensional (2D) supramolecular network through C–H···π and O···π interactions. Coordination polymer <b>4</b> forms H-bonded 3D chainlike supramolecular architecture. Coordination polymer <b>5</b> forms a 3D supramolecular sheet-like structure, whereas coordination polymer <b>6</b> and coordination polymer <b>7</b> forms a 2D lamellar structure through π···π and C–H···π interactions. Manganese coordination polymer <b>1</b> shows weak antiferromagnetic interactions between chains at low temperature and also exhibits single chain magnetic behavior. Coordination polymers <b>2</b> and <b>3</b> show saturation value of magnetic moment at 2 K and 7 T, which are lower than the spin-only Co­(II) ion. Coordination polymer <b>4</b> show spin-only values for Ni­(II) ion. The room-temperature χ_M<i>T</i> value for coordination polymer <b>5</b> is close to the spin-only value for two Cu­(II) ions. With lowering of the temperature, the χ_M<i>T</i> value remains constant to 35 K, from where the value begins to decrease to a minimum at 2 K. For copper coordination polymer <b>6</b> value of χ_M<i>T</i> smoothly decreases with lowering of the temperature to attain a quasi plateau between 80 K and 35 K, and it further sharply increases at 2 K. Coordination polymer <b>7</b> shows spin-only Cu­(II) ion. These coordination polymers in solid state show quenching of fluorescence emission of ligand <b>L</b>, as well as a shift of emission toward a shorter wavelength

Molecular Iron(III) Phosphonates: Synthesis, Structure, Magnetism, and Mössbauer Studies

The reaction of Fe­(ClO₄)₂·6H₂O with <i>t</i>-BuPO₃H₂ or Cl₃CPO₃H₂ in the presence of an ancillary pyrazole phenolate as a coligand, H₂phpzH [H₂phpzH = 3(5)-(2-hydroxyphenyl)­pyrazole], afforded tetra- and pentanuclear Fe­(III) phosphonate complexes [Fe₄(<i>t</i>-BuPO₃)₄(HphpzH)₄]·5CH₃CN·5CH₂Cl₂ (<b>1</b>) and [HNEt₃]₂[Fe₅(μ₃-O)­(μ-OH)₂ (Cl₃CPO₃)₃­(HphpzH)₅­(μ-phpzH]·3CH₃CN·2H₂O (<b>2</b>). Single-crystal X-ray structural analysis reveals that <b>1</b> possesses a cubic double-4-ring (D4R) core similar to what is found in zeolites. The molecular structure of <b>2</b> reveals it to be pentanuclear. It crystallizes in the chiral <i>P</i>1 space group. Magnetic studies on <b>1</b> and <b>2</b> have also been carried out, which reveal that the bridging phosphonate ligands mediate weak antiferromagnetic interactions between the Fe­(III) ions. Magnetization dynamics of <b>1</b> and <b>2</b> have been corroborated by a Mössbauer spectroscopy analysis

An Undecanuclear Ferrimagnetic Cu₉Dy₂ Single Molecule Magnet Achieved through Ligand Fine-Tuning

We describe the concept of increasing the nuclearity of a previously reported high-spin Cu₅Gd₂ core using a “fine-tuning” ligand approach. Thus, two Cu₉Ln₂ coordination clusters, with Ln = Dy (<b>1</b>) and Gd (<b>2</b>), were synthesized with the Gd compound having a ground spin state of ¹⁷/₂ and the Dy analogue showing single-molecule-magnet behavior in zero field

Spontaneous Resolution in Homochiral Helical [Ln(nic)₂(Hnic)(NO₃)] Coordination Polymers Constructed from a Rigid Non-chiral Organic Ligand

A series of homochiral lanthanide nicotinate helical coordination polymers [Ln^III(nic)₂(Hnic)­(NO₃)] (Ln = Eu (<b>1</b>), Gd (<b>2</b>), Tb (<b>3</b>); Hnic = nicotinic acid) has been solvothermally synthesized using nicotinic acid. In the resulting chains, chirality is not induced by a chiral agent but appears spontaneously <i>via</i> intrachain hydrogen bondings. Compounds <b>2</b> and <b>3</b> were magnetically characterized, and luminescent properties were observed for compounds <b>1</b> and <b>3</b>