Direct synthesis of a tetranuclear erbium(III) hydroxo cluster bearing a saturated Schiff base

Solvent influence on the formation of anhydrous mononuclear or multinuclear lanthanide complexes containing tetradentate Schiff-base ligands

“…Compound 3 and its isomorph 4 exhibit several noteworthy structural features, the first of which is the boat conformation for the six-membered chelate ring comprised of Ln, N(1), C(5), C(6), C(7), and N(2). This chelate ring conformation, without crystallographic disorder on the C(5)-C(7) positions, 20 has previously been observed in all mononuclear five-coordinate XLn 3ϩ (SB) complexes bearing unsubstituted propyl spacers 8, 15 and produces a short (∼2.7 Å) interaction between the metal and a diastereotopic proton on the central (C( 6)) methylene carbon (Fig. 3(a)).…”

“…Toward this goal, our previous work. 7,8, 15 and that of others 12-14 served as a guide. Rationalizing that the larger Ln 3ϩ (Ln 3ϩ = La 3ϩ and Nd 3ϩ ) ions might compensate for a third methyl group on each silyl group of the coordinated amide, we undertook our standard ((TMS) 2 N)Ln 3ϩ (SB) synthesis in THF solvent (Scheme 1) which could bind to the metal ion and preclude homologation.…”

Solvent influence on the formation of anhydrous mononuclear or multinuclear lanthanide complexes containing tetradentate Schiff-base ligands

“…Compound 3 and its isomorph 4 exhibit several noteworthy structural features, the first of which is the boat conformation for the six-membered chelate ring comprised of Ln, N(1), C(5), C(6), C(7), and N(2). This chelate ring conformation, without crystallographic disorder on the C(5)-C(7) positions, 20 has previously been observed in all mononuclear five-coordinate XLn 3ϩ (SB) complexes bearing unsubstituted propyl spacers 8, 15 and produces a short (∼2.7 Å) interaction between the metal and a diastereotopic proton on the central (C( 6)) methylene carbon (Fig. 3(a)).…”

“…Toward this goal, our previous work. 7,8, 15 and that of others 12-14 served as a guide. Rationalizing that the larger Ln 3ϩ (Ln 3ϩ = La 3ϩ and Nd 3ϩ ) ions might compensate for a third methyl group on each silyl group of the coordinated amide, we undertook our standard ((TMS) 2 N)Ln 3ϩ (SB) synthesis in THF solvent (Scheme 1) which could bind to the metal ion and preclude homologation.…”

Synthesis, Crystal Structure, and Modelling of a New Tetramer Complex of Europium

“…Indeed, the presence of a β-diketonate chelating group in the ETAresidues allows the strong coordination of a single molecule to two vacant coordinative positions of each Eu 3+ cation via a typical O,Ochelating fashion as described above (η 2 -ETA -; Scheme 2a). This O,O-chelating coordination mode is substantially different from that described for related structures containing carboxylate groups, as observed for the vast majority of related cubanetype clusters, [34][35][36][37][38][39][41][42][43][44][45] in the sense that these latter moieties preferentially establish syn,syn-bridges between neighboring cations belonging to the core of the clusters. The exceptions are for the structures reported by Serre et al 41 and Zheng et al 43 Nonetheless, in these structures the dominant coordination mode is still the syn,syn-bridging one, and the lanthanides tend to organize into aggregates rather than into isolated tetramers.…”

“…The structure contains an unprecedented and remarkable discrete neutral complex in which the Eu 3+ cations are joined together by three μ 3 -bridging hydroxyl groups (O(1), O(2), and O(3)) plus nine anionic ETA - chelating residues (Figures a and b). A search in the literature and in the Cambridge Structural Database (CSD, version 5.27, November 2005) , reveals that despite isolated tetramers − or aggregates ,,− of lanthanide cations being already known the vast majority shares striking topological resemblance to a cubane-type cluster 34-39,41-45 (i.e., the core of the complex structures have four lanthanide centers joined together by another four hydroxyl groups placed in opposite vertices of the cuboidal arrangement; Scheme a) and only a handful contain Eu 3+ cations. ,,, Thus, to the best of our knowledge, the tetrametallic [Eu 4 (η 3 -ETA) 3 (η 2 -ETA) 6 (μ 3 -OH) 3 (H 2 O) 3 ] complex represents the first example of a discrete moiety in which the core is best described as an open-cubane-type cluster structure (Scheme b) with the position of the fourth μ 3 -bridging hydroxyl group being instead occupied by three coordinated water molecules, which are further involved in strong hydrogen bonds (Figure c and the text in the following paragraphs).

1 Schematic Drawings of the: (a) Known Cubane-like {Ln 4 (μ 3 -OH) 4 } Clusters and (b) {Eu 4 (μ 3 -OH) 3 (H 2 O) 3 } Core of the [Eu 4 (η 3 -ETA) 3 (η 2 -ETA) 6 (μ 3 -OH) 3 (H 2 O) 3 ] Complex, Emphasizing the Replacement of a μ 3 -Bridging Hydroxyl Group by Three Coordinated Water Molecules

…”

Postsynthetic Installation of Lanthanide Cubane Clusters in a 3D Hydrogen-Bonded Framework of IrIII4ZnII4 Multicarboxylates

“…4−6 One of the representative clusters of this class is the tetranuclear Ln 4 (OH) 4 with a cubane form. 6−25 While several supporting ligands, such as amino carboxylates, 6,10−13 aromatic carboxylates, 6,14−22 Schiff bases, 23 and β-diketonates, 24 have been used to produce Ln 4 (OH) 4 cubanes via a ligand-controlled approach, their rational synthesis remains challenging due to the large pH dependency of hydrolysis and the flexibility of lanthanide coordination geometries. 4,5,25 To overcome the limitation of the ligand-controlled approach, the use of interstitial spaces in coordination compounds is an alternative way to generate Ln 4 (OH) 4 cubane clusters.…”

Solvent influence on the formation of anhydrous mononuclear or multinuclear lanthanide complexes containing tetradentate Schiff-base ligands

“…Compound 3 and its isomorph 4 exhibit several noteworthy structural features, the first of which is the boat conformation for the six-membered chelate ring comprised of Ln, N(1), C(5), C(6), C(7), and N(2). This chelate ring conformation, without crystallographic disorder on the C(5)-C(7) positions, 20 has previously been observed in all mononuclear five-coordinate XLn 3ϩ (SB) complexes bearing unsubstituted propyl spacers 8, 15 and produces a short (∼2.7 Å) interaction between the metal and a diastereotopic proton on the central (C( 6)) methylene carbon (Fig. 3(a)).…”

“…Toward this goal, our previous work. 7,8, 15 and that of others 12-14 served as a guide. Rationalizing that the larger Ln 3ϩ (Ln 3ϩ = La 3ϩ and Nd 3ϩ ) ions might compensate for a third methyl group on each silyl group of the coordinated amide, we undertook our standard ((TMS) 2 N)Ln 3ϩ (SB) synthesis in THF solvent (Scheme 1) which could bind to the metal ion and preclude homologation.…”

Synthesis, Crystal Structure, and Modelling of a New Tetramer Complex of Europium

“…Indeed, the presence of a β-diketonate chelating group in the ETAresidues allows the strong coordination of a single molecule to two vacant coordinative positions of each Eu 3+ cation via a typical O,Ochelating fashion as described above (η 2 -ETA -; Scheme 2a). This O,O-chelating coordination mode is substantially different from that described for related structures containing carboxylate groups, as observed for the vast majority of related cubanetype clusters, [34][35][36][37][38][39][41][42][43][44][45] in the sense that these latter moieties preferentially establish syn,syn-bridges between neighboring cations belonging to the core of the clusters. The exceptions are for the structures reported by Serre et al 41 and Zheng et al 43 Nonetheless, in these structures the dominant coordination mode is still the syn,syn-bridging one, and the lanthanides tend to organize into aggregates rather than into isolated tetramers.…”

“…The structure contains an unprecedented and remarkable discrete neutral complex in which the Eu 3+ cations are joined together by three μ 3 -bridging hydroxyl groups (O(1), O(2), and O(3)) plus nine anionic ETA - chelating residues (Figures a and b). A search in the literature and in the Cambridge Structural Database (CSD, version 5.27, November 2005) , reveals that despite isolated tetramers − or aggregates ,,− of lanthanide cations being already known the vast majority shares striking topological resemblance to a cubane-type cluster 34-39,41-45 (i.e., the core of the complex structures have four lanthanide centers joined together by another four hydroxyl groups placed in opposite vertices of the cuboidal arrangement; Scheme a) and only a handful contain Eu 3+ cations. ,,, Thus, to the best of our knowledge, the tetrametallic [Eu 4 (η 3 -ETA) 3 (η 2 -ETA) 6 (μ 3 -OH) 3 (H 2 O) 3 ] complex represents the first example of a discrete moiety in which the core is best described as an open-cubane-type cluster structure (Scheme b) with the position of the fourth μ 3 -bridging hydroxyl group being instead occupied by three coordinated water molecules, which are further involved in strong hydrogen bonds (Figure c and the text in the following paragraphs).

1 Schematic Drawings of the: (a) Known Cubane-like {Ln 4 (μ 3 -OH) 4 } Clusters and (b) {Eu 4 (μ 3 -OH) 3 (H 2 O) 3 } Core of the [Eu 4 (η 3 -ETA) 3 (η 2 -ETA) 6 (μ 3 -OH) 3 (H 2 O) 3 ] Complex, Emphasizing the Replacement of a μ 3 -Bridging Hydroxyl Group by Three Coordinated Water Molecules

…”

Postsynthetic Installation of Lanthanide Cubane Clusters in a 3D Hydrogen-Bonded Framework of IrIII4ZnII4 Multicarboxylates

“…4−6 One of the representative clusters of this class is the tetranuclear Ln 4 (OH) 4 with a cubane form. 6−25 While several supporting ligands, such as amino carboxylates, 6,10−13 aromatic carboxylates, 6,14−22 Schiff bases, 23 and β-diketonates, 24 have been used to produce Ln 4 (OH) 4 cubanes via a ligand-controlled approach, their rational synthesis remains challenging due to the large pH dependency of hydrolysis and the flexibility of lanthanide coordination geometries. 4,5,25 To overcome the limitation of the ligand-controlled approach, the use of interstitial spaces in coordination compounds is an alternative way to generate Ln 4 (OH) 4 cubane clusters.…”

Solvent influence on the formation of anhydrous mononuclear or multinuclear lanthanide complexes containing tetradentate Schiff-base ligands

“…Compound 3 and its isomorph 4 exhibit several noteworthy structural features, the first of which is the boat conformation for the six-membered chelate ring comprised of Ln, N(1), C(5), C(6), C(7), and N(2). This chelate ring conformation, without crystallographic disorder on the C(5)-C(7) positions, 20 has previously been observed in all mononuclear five-coordinate XLn 3ϩ (SB) complexes bearing unsubstituted propyl spacers 8, 15 and produces a short (∼2.7 Å) interaction between the metal and a diastereotopic proton on the central (C( 6)) methylene carbon (Fig. 3(a)).…”

“…Toward this goal, our previous work. 7,8, 15 and that of others 12-14 served as a guide. Rationalizing that the larger Ln 3ϩ (Ln 3ϩ = La 3ϩ and Nd 3ϩ ) ions might compensate for a third methyl group on each silyl group of the coordinated amide, we undertook our standard ((TMS) 2 N)Ln 3ϩ (SB) synthesis in THF solvent (Scheme 1) which could bind to the metal ion and preclude homologation.…”

Synthesis, Crystal Structure, and Modelling of a New Tetramer Complex of Europium

“…Indeed, the presence of a β-diketonate chelating group in the ETAresidues allows the strong coordination of a single molecule to two vacant coordinative positions of each Eu 3+ cation via a typical O,Ochelating fashion as described above (η 2 -ETA -; Scheme 2a). This O,O-chelating coordination mode is substantially different from that described for related structures containing carboxylate groups, as observed for the vast majority of related cubanetype clusters, [34][35][36][37][38][39][41][42][43][44][45] in the sense that these latter moieties preferentially establish syn,syn-bridges between neighboring cations belonging to the core of the clusters. The exceptions are for the structures reported by Serre et al 41 and Zheng et al 43 Nonetheless, in these structures the dominant coordination mode is still the syn,syn-bridging one, and the lanthanides tend to organize into aggregates rather than into isolated tetramers.…”

“…The structure contains an unprecedented and remarkable discrete neutral complex in which the Eu 3+ cations are joined together by three μ 3 -bridging hydroxyl groups (O(1), O(2), and O(3)) plus nine anionic ETA - chelating residues (Figures a and b). A search in the literature and in the Cambridge Structural Database (CSD, version 5.27, November 2005) , reveals that despite isolated tetramers − or aggregates ,,− of lanthanide cations being already known the vast majority shares striking topological resemblance to a cubane-type cluster 34-39,41-45 (i.e., the core of the complex structures have four lanthanide centers joined together by another four hydroxyl groups placed in opposite vertices of the cuboidal arrangement; Scheme a) and only a handful contain Eu 3+ cations. ,,, Thus, to the best of our knowledge, the tetrametallic [Eu 4 (η 3 -ETA) 3 (η 2 -ETA) 6 (μ 3 -OH) 3 (H 2 O) 3 ] complex represents the first example of a discrete moiety in which the core is best described as an open-cubane-type cluster structure (Scheme b) with the position of the fourth μ 3 -bridging hydroxyl group being instead occupied by three coordinated water molecules, which are further involved in strong hydrogen bonds (Figure c and the text in the following paragraphs).

1 Schematic Drawings of the: (a) Known Cubane-like {Ln 4 (μ 3 -OH) 4 } Clusters and (b) {Eu 4 (μ 3 -OH) 3 (H 2 O) 3 } Core of the [Eu 4 (η 3 -ETA) 3 (η 2 -ETA) 6 (μ 3 -OH) 3 (H 2 O) 3 ] Complex, Emphasizing the Replacement of a μ 3 -Bridging Hydroxyl Group by Three Coordinated Water Molecules

…”

Postsynthetic Installation of Lanthanide Cubane Clusters in a 3D Hydrogen-Bonded Framework of IrIII4ZnII4 Multicarboxylates

“…4−6 One of the representative clusters of this class is the tetranuclear Ln 4 (OH) 4 with a cubane form. 6−25 While several supporting ligands, such as amino carboxylates, 6,10−13 aromatic carboxylates, 6,14−22 Schiff bases, 23 and β-diketonates, 24 have been used to produce Ln 4 (OH) 4 cubanes via a ligand-controlled approach, their rational synthesis remains challenging due to the large pH dependency of hydrolysis and the flexibility of lanthanide coordination geometries. 4,5,25 To overcome the limitation of the ligand-controlled approach, the use of interstitial spaces in coordination compounds is an alternative way to generate Ln 4 (OH) 4 cubane clusters.…”