Homochiral, Helical Coordination Complexes of Lanthanides(III) and Mixed-Metal Lanthanides(III): Impact of the 1,8-Naphthalimide Supramolecular Tecton on Structure, Magnetic Properties, and Luminescence

The reactions of the lithium salt of (<i>S</i>)-2-(1,8-naphthal­imido)-3-hydroxy­propanoate (<b>L</b>_<b>ser</b>^–), an enantio­pure carboxylate ligand containing a 1,8-naphthal­imide π···π stacking supra­molecular tecton and an alcohol functional group, with La­(NO₃)₃, Ce­(NO₃)₃, SmCl₃, Eu­(NO₃)₃, Gd­(NO₃)₃, Tb­(NO₃)₃, and Dy­(NO₃)₃ under solvo­thermal conditions (water/​ethanol) produced single crystals (characterized by single-crystal X-ray crystallography) of [La₃­(<b>L</b>_<b>ser</b>)₈­(OH)­(H₂O)]·​(H₂O,​EtOH)_<i>x</i> (<b>1</b>), [Ce₃­(<b>L</b>_<b>ser</b>)₈­(OH)­(H₂O)]·​(H₂O,​EtOH)_<i>x</i> (<b>2</b>), [Sm₃­(<b>L</b>_<b>ser</b>)₈­(OEt)]·​(H₂O,​EtOH)_<i>x</i> (<b>3</b>), [Eu₃­(<b>L</b>_<b>ser</b>)₈­(OEt)]·​(H₂O,​EtOH)_<i>x</i> (<b>4</b>), [Gd₃­(<b>L</b>_<b>ser</b>)₈­(OEt)]·​(H₂O,​EtOH)_<i>x</i> (<b>5</b>), [Tb₃­(<b>L</b>_<b>ser</b>)₈­(OEt)]·​(H₂O,​EtOH)_<i>x</i> (<b>6</b>), and [Dy₃­(<b>L</b>_<b>ser</b>)₈­(OEt)]·​(H₂O,​EtOH)_<i>x</i> (<b>7</b>), respectively. Mixed-metal complexes [Ce_2.3Tb_0.7­(<b>L</b>_<b>ser</b>)₈(OH)]·​(H₂O,​EtOH)_<i>x</i> (<b>8</b>), [Gd_0.4Tb_2.6­(<b>L</b>_<b>ser</b>)₈­(OEt)]·​(H₂O,​EtOH)_<i>x</i> (<b>9</b>), and [Ce_1.4Gd_0.3Tb_1.3­(<b>L</b>_<b>ser</b>)₈(OH)]·​(H₂O,​EtOH)_<i>x</i> (<b>10</b>) were prepared by using two or more types of lanthanides in the solvo­thermal reactions (additional mixed-metal complexes were prepared and characterized by ICP-MS). Single crystals of compounds <b>1</b>–<b>10</b> are isostructural: trinuclear, carboxylate-bonded helicates organized by the non-covalent, π···π stacking interactions of the 1,8-naphthal­imide groups into <i>inter­twined M</i> helices, with a pitch of 56 Å, that are further arranged into a three-dimensional supra­molecular framework by additional π···π stacking interactions. Magnetic measurements of several compounds were as expected for the metal(s) present, indicating no significant interactions between metals within the helicates. The Ce complex <b>2</b> showed weak anti­ferro­magnetic ordering below 50 K. All of the complexes, with the exception of <b>2</b>, showed luminescence based on the 1,8-naphthal­imide group. Complex <b>2</b> has no emission, and complexes with mixed Ce/Tb ratios showed significant quenching of the naphthal­imide-based luminescence, as quantitated with solid-state, absolute quantum yield measurements of these mixed-metal and the pure metal complexes. Lanthanide-based luminescence was only observed for the Eu complex <b>4</b>

Zinc Paddlewheel Dimers Containing a Strong π···π Stacking Supramolecular Synthon: Designed Single-Crystal to Single-Crystal Phase Changes and Gas/Solid Guest Exchange

The ligand 4-(1,8-naphthalimido)benzoate, <b>L</b>_<b>C4</b>^<b>–</b>, containing a linear link between the strong π···π stacking 1,8-naphthalimide supramolecular synthon and the carboxylate donor group, reacts with Zn(O₂CCH₃)₂(H₂O)₂ in the presence of dimethylsulfoxide (DMSO) to yield [Zn₂(<b>L</b>_<b>C4</b>)₄(DMSO)₂]·2(CH₂Cl₂). This compound contains the “paddlewheel” Zn₂(O₂CR)₄ secondary building unit (SBU) that organizes the rigid phenylene and naphthalimide rings of the carboxylate ligands in a square arrangement. The supramolecular architecture is dominated by π···π stacking interactions between naphthalimide rings of one dimer with four adjacent dimers, essentially at right angles, forming an open three-dimensional network structure. Two symmetry equivalent networks of this type interpenetrate generating overall a densely packed three-dimensional, 2-fold interpenetrated architecture in which the CH₂Cl₂ solvate molecules are trapped in isolated pockets. Upon cooling, single crystals of [Zn₂(<b>L</b>_<b>C4</b>)₄(DMSO)₂]·2(CH₂Cl₂) undergo two distinct crystallographic phase transitions, as characterized by X-ray diffraction at different temperatures, without loss of crystallinity. These two new phases have supramolecular structures very similar to the room temperature structure, but changes in the ordering of the CH₂Cl₂ solvate cause shifting of the naphthalimide rings and a lowering of the symmetry. Crystals of [Zn₂(<b>L</b>_<b>C4</b>)₄(DMSO)₂]·2(CH₂Cl₂) undergo a single-crystal to single-crystal gas/solid guest exchange upon exposure to atmospheric moisture, or faster if placed under vacuum or heated under dry gas to 100 °C, followed by atmospheric moisture, to yield [Zn₂(<b>L</b>_<b>C4</b>)₄(DMSO)₂]·3.9(H₂O). The molecular and supramolecular structures of this new compound are very similar to the dichloromethane adduct, with now the water molecules encapsulated into the framework. The remarkable feature of both the phase changes and exchange of solvates is that this robust network is not porous; local distortions (ring slippage and tilting changes) of the π···π stacking interactions of the naphthalimide rings that organize these structures allow these changes to take place without the loss of crystallinity. The complexes [Zn₂(<b>L</b>_<b>C4</b>)₄(DMSO)₂]·2(CH₂Cl₂) and [Zn₂(<b>L</b>_<b>C4</b>)₄(DMSO)₂]·3.9(H₂O) show green emission in the solid state

Zinc Paddlewheel Dimers Containing a Strong π···π Stacking Supramolecular Synthon: Designed Single-Crystal to Single-Crystal Phase Changes and Gas/Solid Guest Exchange

The ligand 4-(1,8-naphthalimido)benzoate, <b>L</b>_<b>C4</b>^<b>–</b>, containing a linear link between the strong π···π stacking 1,8-naphthalimide supramolecular synthon and the carboxylate donor group, reacts with Zn(O₂CCH₃)₂(H₂O)₂ in the presence of dimethylsulfoxide (DMSO) to yield [Zn₂(<b>L</b>_<b>C4</b>)₄(DMSO)₂]·2(CH₂Cl₂). This compound contains the “paddlewheel” Zn₂(O₂CR)₄ secondary building unit (SBU) that organizes the rigid phenylene and naphthalimide rings of the carboxylate ligands in a square arrangement. The supramolecular architecture is dominated by π···π stacking interactions between naphthalimide rings of one dimer with four adjacent dimers, essentially at right angles, forming an open three-dimensional network structure. Two symmetry equivalent networks of this type interpenetrate generating overall a densely packed three-dimensional, 2-fold interpenetrated architecture in which the CH₂Cl₂ solvate molecules are trapped in isolated pockets. Upon cooling, single crystals of [Zn₂(<b>L</b>_<b>C4</b>)₄(DMSO)₂]·2(CH₂Cl₂) undergo two distinct crystallographic phase transitions, as characterized by X-ray diffraction at different temperatures, without loss of crystallinity. These two new phases have supramolecular structures very similar to the room temperature structure, but changes in the ordering of the CH₂Cl₂ solvate cause shifting of the naphthalimide rings and a lowering of the symmetry. Crystals of [Zn₂(<b>L</b>_<b>C4</b>)₄(DMSO)₂]·2(CH₂Cl₂) undergo a single-crystal to single-crystal gas/solid guest exchange upon exposure to atmospheric moisture, or faster if placed under vacuum or heated under dry gas to 100 °C, followed by atmospheric moisture, to yield [Zn₂(<b>L</b>_<b>C4</b>)₄(DMSO)₂]·3.9(H₂O). The molecular and supramolecular structures of this new compound are very similar to the dichloromethane adduct, with now the water molecules encapsulated into the framework. The remarkable feature of both the phase changes and exchange of solvates is that this robust network is not porous; local distortions (ring slippage and tilting changes) of the π···π stacking interactions of the naphthalimide rings that organize these structures allow these changes to take place without the loss of crystallinity. The complexes [Zn₂(<b>L</b>_<b>C4</b>)₄(DMSO)₂]·2(CH₂Cl₂) and [Zn₂(<b>L</b>_<b>C4</b>)₄(DMSO)₂]·3.9(H₂O) show green emission in the solid state

Homochiral, Helical Coordination Complexes of Lanthanides(III) and Mixed-Metal Lanthanides(III): Impact of the 1,8-Naphthalimide Supramolecular Tecton on Structure, Magnetic Properties, and Luminescence

The reactions of the lithium salt of (<i>S</i>)-2-(1,8-naphthal­imido)-3-hydroxy­propanoate (<b>L</b>_<b>ser</b>^–), an enantio­pure carboxylate ligand containing a 1,8-naphthal­imide π···π stacking supra­molecular tecton and an alcohol functional group, with La­(NO₃)₃, Ce­(NO₃)₃, SmCl₃, Eu­(NO₃)₃, Gd­(NO₃)₃, Tb­(NO₃)₃, and Dy­(NO₃)₃ under solvo­thermal conditions (water/​ethanol) produced single crystals (characterized by single-crystal X-ray crystallography) of [La₃­(<b>L</b>_<b>ser</b>)₈­(OH)­(H₂O)]·​(H₂O,​EtOH)_<i>x</i> (<b>1</b>), [Ce₃­(<b>L</b>_<b>ser</b>)₈­(OH)­(H₂O)]·​(H₂O,​EtOH)_<i>x</i> (<b>2</b>), [Sm₃­(<b>L</b>_<b>ser</b>)₈­(OEt)]·​(H₂O,​EtOH)_<i>x</i> (<b>3</b>), [Eu₃­(<b>L</b>_<b>ser</b>)₈­(OEt)]·​(H₂O,​EtOH)_<i>x</i> (<b>4</b>), [Gd₃­(<b>L</b>_<b>ser</b>)₈­(OEt)]·​(H₂O,​EtOH)_<i>x</i> (<b>5</b>), [Tb₃­(<b>L</b>_<b>ser</b>)₈­(OEt)]·​(H₂O,​EtOH)_<i>x</i> (<b>6</b>), and [Dy₃­(<b>L</b>_<b>ser</b>)₈­(OEt)]·​(H₂O,​EtOH)_<i>x</i> (<b>7</b>), respectively. Mixed-metal complexes [Ce_2.3Tb_0.7­(<b>L</b>_<b>ser</b>)₈(OH)]·​(H₂O,​EtOH)_<i>x</i> (<b>8</b>), [Gd_0.4Tb_2.6­(<b>L</b>_<b>ser</b>)₈­(OEt)]·​(H₂O,​EtOH)_<i>x</i> (<b>9</b>), and [Ce_1.4Gd_0.3Tb_1.3­(<b>L</b>_<b>ser</b>)₈(OH)]·​(H₂O,​EtOH)_<i>x</i> (<b>10</b>) were prepared by using two or more types of lanthanides in the solvo­thermal reactions (additional mixed-metal complexes were prepared and characterized by ICP-MS). Single crystals of compounds <b>1</b>–<b>10</b> are isostructural: trinuclear, carboxylate-bonded helicates organized by the non-covalent, π···π stacking interactions of the 1,8-naphthal­imide groups into <i>inter­twined M</i> helices, with a pitch of 56 Å, that are further arranged into a three-dimensional supra­molecular framework by additional π···π stacking interactions. Magnetic measurements of several compounds were as expected for the metal(s) present, indicating no significant interactions between metals within the helicates. The Ce complex <b>2</b> showed weak anti­ferro­magnetic ordering below 50 K. All of the complexes, with the exception of <b>2</b>, showed luminescence based on the 1,8-naphthal­imide group. Complex <b>2</b> has no emission, and complexes with mixed Ce/Tb ratios showed significant quenching of the naphthal­imide-based luminescence, as quantitated with solid-state, absolute quantum yield measurements of these mixed-metal and the pure metal complexes. Lanthanide-based luminescence was only observed for the Eu complex <b>4</b>

Homochiral Helical Metal–Organic Frameworks of Potassium

Two trifunctional ligands built from enantiopure amino acids and containing a 1,8-naphthalimide group have been used to prepare two new complexes of potassium that have extended structures based on homochiral-rod secondary building units. One structure is a three-dimensional metal–organic framework (MOF), while the other is a two-dimensional solid that is organized into a supramolecular MOF by strong π···π-stacking interactions of the naphthalimide groups in the third dimension

Homochiral Helical Metal–Organic Frameworks of Potassium

Two trifunctional ligands built from enantiopure amino acids and containing a 1,8-naphthalimide group have been used to prepare two new complexes of potassium that have extended structures based on homochiral-rod secondary building units. One structure is a three-dimensional metal–organic framework (MOF), while the other is a two-dimensional solid that is organized into a supramolecular MOF by strong π···π-stacking interactions of the naphthalimide groups in the third dimension

Supramolecular Metal–Organic Frameworks of s- and f‑Block Metals: Impact of 1,8-Naphthalimide Functional Group

The new ligand 5-(1,8-naphthalimido)­isophthalate (<b>L</b>_<b>135</b>^<b>2–</b>), containing two carboxylate donor groups and the 1,8-naphthalimide supramolecular tecton, has been used under solvothermal conditions to prepare a series of group 2, lanthanide, and actinide metal complexes: [Ca₄(<b>L</b>_<b>135</b>)₄­(H₂O)₈]­·(H₂O)_9.5­(DMF)_2.6 (<b>1</b>), Ba­(<b>L</b>_<b>135</b>)­(H₂O)_1.5­(DMF)_0.5 (<b>2</b>), La₂(<b>L</b>_<b>135</b>)₃­(DMF)₄ (<b>3</b>), Ce₂(<b>L</b>_<b>135</b>)₃­(DMF)₄ (<b>4</b>), Eu₂(<b>L</b>_<b>135</b>)₃­(DMF)₄ (<b>5</b>), Tb₂(<b>L</b>_<b>135</b>)₃­(DMF)₄ (<b>6</b>), [UO₂(<b>L</b>_<b>135</b>)­(DMF)]­·(py)_0.5­(EtOH)_0.5 (<b>7</b>), and Th­(<b>L</b>_<b>135</b>)­(NO₃)₂­(DMF)₂]­·(DMF)₂ (<b>8</b>). The solid state structure of the calcium complex <b>1</b> is based on helical rod-shaped secondary building-units (SBUs) of edge-shared polyhedra bridged by oxygen atoms from the carboxylate groups. The crystals are racemic, with the one-dimensional (1D) helical rods organized by π···π stacking interactions of the naphthalimide group into a three-dimensional (3D) supramolecular metal-organic framework (SMOF) structure. Although the structure of the barium complex <b>2</b> also contains rod-shaped SBUs, the rods are linked through the aryl backbone of the ditopic <b>L</b>_<b>135</b>^<b>2–</b> ligands into two-dimensional (2D) sheets. The sheets are further engaged in naphthalimide π···π stacking interactions to build a 3D SMOF. The lanthanide­(III) complexes <b>3</b>–<b>6</b> are isostructural, based on binuclear SBUs linked through the ligands into a square-shaped, 2D grid pattern, with π-stacking interactions linking adjacent sheets to generate a 3D SMOF. The uranium­(VI) complex <b>7</b> contains 7-coordinate pentagonal bipyramidal uranyl cations bridged through the ligands into 1D ribbons. The solid state structure of the thorium­(IV) complex <b>8</b> consists of 10-coordinate thorium cations, also bridged through the ligands into 1D ribbons. Both of these actinide structures are organized into 2D supramolecular sheets by π-stacking interactions. Compounds <b>1</b>, <b>2</b>, <b>3</b>, <b>6</b>, and <b>8</b> exhibit solid-state luminescence dominated by the naphthalimide chromophore in the ligand. The group 2 complexes are slightly red-shifted, and the lanthanum complex <b>3</b> and the thorium complex <b>8</b> are slightly blue-shifted with respect to the ligand. The terbium compound, <b>6</b>, is greatly blue-shifted by ∼75 nm, and naphthalimide sensitization of the metal emission occurs for the europium complex <b>5</b>. The cerium­(III) and uranyl­(VI) compounds <b>4</b> and <b>7</b> have no solid state emission

Framework Complexes of Group 2 Metals Organized by Homochiral Rods and π···π Stacking Forces: A Breathing Supramolecular MOF

The reactions of the potassium salts of the ligands (<i>S</i>)-2-(1,8-naphthalimido)­propanoate (K<b>L</b>_<b>ala</b>), (<i>S</i>)-2-(1,8-naphthalimido)-3-hydroxypropanoate (K<b>L</b>_<b>ser</b>), and (<i>R</i>)-2-(1,8-naphthalimido)­propanoate (K<b>L</b>_<b>ala</b>*), enantiopure carboxylate ligands containing a 1,8-naphthalimide π···π stacking supramolecular tecton, and, in the case of <b>L</b>_<b>ser</b>^<b>–</b>, an alcohol functional group with calcium or strontium nitrate under solvothermal conditions produce crystalline [Ca­(<b>L</b>_<b>ala</b>)₂(H₂O)]·(H₂O) (<b>1</b>); [Ca­(<b>L</b>_<b>ser</b>)₂]·(H₂O)₂ (<b>2</b>); [Sr­(<b>L</b>_<b>ala</b>)₂(H₂O)]·(H₂O)₃ (<b>3</b>); [Sr­(<b>L</b>_<b>ala</b>*)₂(H₂O)]·(H₂O)₃ (<b>3</b>*); and [Sr­(<b>L</b>_<b>ser</b>)₂(H₂O)] (<b>5</b>). Placing <b>3</b> under vacuum removes the interstitial waters to produce [Sr­(<b>L</b>_<b>ala</b>)₂(H₂O)] (<b>4</b>) in a single-crystal to single-crystal transformation; introduction of water vapor to <b>4</b> leads to the reformation of crystalline <b>3</b>. Each of these new complexes has a solid-state structure based on homochiral rod secondary building unit (SBUs) central cores. Supramolecular π···π stacking interactions between 1,8-naphthalimide rings link adjacent rod SBUs into three-dimensional structures for <b>1</b>, <b>3</b>, <b>4</b>, and <b>5</b> and two-dimensional structure for <b>2</b>. Compounds <b>1</b> and <b>3</b> have open one-dimensional channels along the crystallographic <i>c</i> axis that are occupied by disordered solvent. For <b>3</b>, these channels close and open in the reversible single-crystal conversion to <b>4</b>; the π···π stacking interactions of the naphthalimide rings facilitate this process by rotating and slipping. Infrared spectroscopy demonstrated that the rehydration of <b>4</b> with D₂O leads to <b>3d</b>_<b>8</b>, and the process of dehydration and rehydration of <b>3d</b>_<b>8</b> with H₂O leads to <b>3</b>, thus showing exchange of the coordinated water in this process. These forms of <b>3</b> and <b>4</b> were characterized by ¹H, ²H, and ¹³C solid-state NMR spectroscopy, and thermal and luminescence data are reported on all of the complexes

NMR Investigations of Dinuclear, Single-Anion Bridged Copper(II) Metallacycles: Structure and Antiferromagnetic Behavior in Solution

The nuclear magnetic resonance (NMR) spectra of single-anion bridged, dinuclear copper­(II) metallacycles [Cu₂(μ-X)­(μ-<b>L</b>)₂]­(A)₃ (<b>L</b>_{<i><b>m</b></i>} = <i>m</i>-bis­[bis­(1-pyrazolyl)­methyl]­benzene: X = F^–, A = BF₄^–; X = Cl^–, OH^–, A = ClO₄^–; <b>L</b>_{<i><b>m</b></i>}<b>*</b> = <i>m</i>-bis­[bis­(3,5-dimethyl-1-pyrazolyl)­methyl]­benzene: X = CN^–, F^–, Cl^–, OH^–, Br^–, A = ClO₄^–) have relatively sharp ¹H and ¹³C NMR resonances with small hyperfine shifts due to the strong antiferromagnetic superexchange interactions between the two <i>S</i> = ¹/₂ metal centers. The complete assignments of these spectra, except X = CN^–, have been made through a series of NMR experiments: ¹H–¹H COSY, ¹H–¹³C HSQC, ¹H–¹³C HMBC, <i>T</i>₁ measurements and variable-temperature ¹H NMR. The <i>T</i>₁ measurements accurately determine the Cu···H distances in these molecules. In solution, the temperature dependence of the chemical shifts correlate with the population of the paramagnetic triplet (<i>S</i> = 1) and diamagnetic singlet (<i>S</i> = 0) states. This correlation allows the determination of antiferromagnetic exchange coupling constants, −<i>J</i> (<b>Ĥ</b> = −<i>J</i><b>Ŝ</b>₁<b>Ŝ</b>₂), in solution for the <b>L</b>_{<i><b>m</b></i>} compounds 338­(F^–), 460­(Cl^–), 542­(OH^–), for the <b>L</b>_{<i><b>m</b></i>}* compounds 128­(CN^–), 329­(F^–), 717­(Cl^–), 823­(OH^–), and 944­(Br^–) cm^–1, respectively. These values are of similar magnitudes to those previously measured in the solid state (−<i>J</i>_solid = 365, 536, 555, 160, 340, 720, 808, and 945 cm^–1, respectively). This method of using NMR to determine −<i>J</i> values in solution is an accurate and convenient method for complexes with strong antiferromagnetic superexchange interactions. In addition, the similarity between the solution and solid-state −<i>J</i> values of these complexes confirms the information gained from the <i>T</i>₁ measurements: the structures are similar in the two states

Framework Complexes of Group 2 Metals Organized by Homochiral Rods and π···π Stacking Forces: A Breathing Supramolecular MOF

The reactions of the potassium salts of the ligands (<i>S</i>)-2-(1,8-naphthalimido)­propanoate (K<b>L</b>_<b>ala</b>), (<i>S</i>)-2-(1,8-naphthalimido)-3-hydroxypropanoate (K<b>L</b>_<b>ser</b>), and (<i>R</i>)-2-(1,8-naphthalimido)­propanoate (K<b>L</b>_<b>ala</b>*), enantiopure carboxylate ligands containing a 1,8-naphthalimide π···π stacking supramolecular tecton, and, in the case of <b>L</b>_<b>ser</b>^<b>–</b>, an alcohol functional group with calcium or strontium nitrate under solvothermal conditions produce crystalline [Ca­(<b>L</b>_<b>ala</b>)₂(H₂O)]·(H₂O) (<b>1</b>); [Ca­(<b>L</b>_<b>ser</b>)₂]·(H₂O)₂ (<b>2</b>); [Sr­(<b>L</b>_<b>ala</b>)₂(H₂O)]·(H₂O)₃ (<b>3</b>); [Sr­(<b>L</b>_<b>ala</b>*)₂(H₂O)]·(H₂O)₃ (<b>3</b>*); and [Sr­(<b>L</b>_<b>ser</b>)₂(H₂O)] (<b>5</b>). Placing <b>3</b> under vacuum removes the interstitial waters to produce [Sr­(<b>L</b>_<b>ala</b>)₂(H₂O)] (<b>4</b>) in a single-crystal to single-crystal transformation; introduction of water vapor to <b>4</b> leads to the reformation of crystalline <b>3</b>. Each of these new complexes has a solid-state structure based on homochiral rod secondary building unit (SBUs) central cores. Supramolecular π···π stacking interactions between 1,8-naphthalimide rings link adjacent rod SBUs into three-dimensional structures for <b>1</b>, <b>3</b>, <b>4</b>, and <b>5</b> and two-dimensional structure for <b>2</b>. Compounds <b>1</b> and <b>3</b> have open one-dimensional channels along the crystallographic <i>c</i> axis that are occupied by disordered solvent. For <b>3</b>, these channels close and open in the reversible single-crystal conversion to <b>4</b>; the π···π stacking interactions of the naphthalimide rings facilitate this process by rotating and slipping. Infrared spectroscopy demonstrated that the rehydration of <b>4</b> with D₂O leads to <b>3d</b>_<b>8</b>, and the process of dehydration and rehydration of <b>3d</b>_<b>8</b> with H₂O leads to <b>3</b>, thus showing exchange of the coordinated water in this process. These forms of <b>3</b> and <b>4</b> were characterized by ¹H, ²H, and ¹³C solid-state NMR spectroscopy, and thermal and luminescence data are reported on all of the complexes