Self-Assembly of a Mn₉ Nanoscopic Mixed-Valent Cluster: Synthesis, Crystal Structure, and Magnetic Behavior

A rare Mn9 μ3-oxo-centered mixed-valent cluster [Mn9O7(O2CPh)11(thmn)(py)2 (H2O)3] (1) is prepared by assembling an oxo-centered MnIIMnIII2 triangle, [Mn3O(O2CPh)6(py)2(H2O)]·0.5MeCN, as the secondary building unit in the presence of a tripodal alcohol, 1,1,1-tris(hydroxymethyl)nitromethane (H3thmn), as the capping ligand. Complex 1 was formed along with a minor byproduct, [Mn6O2(O2CPh)10(MeCN)4] (2). Complex 1 was characterized by X-ray single-crystal structure analysis and was crystallized in a monoclinic system, space group P21/n, a = 16.214(6) Å, b = 25.874(10) Å, c = 26.497(10) Å, and β = 94.214(7)°. The Manganese−oxo−carboxylate core in 1 looks like a funnel. Variable-temperature magnetic studies down to 2 K reveal the existence of dominant ferromagnetic interaction within the cluster. Alternating current susceptibility data of the cluster show strong frequency dependence of both the real and imaginary parts of susceptibility χ‘ and χ‘ ‘ below 5 K. Moreover, the calculated relaxation time, τ0 = 1.2 × 10-7 s, and the energy barrier, ΔE = 25 K, are consistent with the single-molecule magnetic behavior of 1

Self-Assembly of a Mn₉ Nanoscopic Mixed-Valent Cluster: Synthesis, Crystal Structure, and Magnetic Behavior

A rare Mn9 μ3-oxo-centered mixed-valent cluster [Mn9O7(O2CPh)11(thmn)(py)2 (H2O)3] (1) is prepared by assembling an oxo-centered MnIIMnIII2 triangle, [Mn3O(O2CPh)6(py)2(H2O)]·0.5MeCN, as the secondary building unit in the presence of a tripodal alcohol, 1,1,1-tris(hydroxymethyl)nitromethane (H3thmn), as the capping ligand. Complex 1 was formed along with a minor byproduct, [Mn6O2(O2CPh)10(MeCN)4] (2). Complex 1 was characterized by X-ray single-crystal structure analysis and was crystallized in a monoclinic system, space group P21/n, a = 16.214(6) Å, b = 25.874(10) Å, c = 26.497(10) Å, and β = 94.214(7)°. The Manganese−oxo−carboxylate core in 1 looks like a funnel. Variable-temperature magnetic studies down to 2 K reveal the existence of dominant ferromagnetic interaction within the cluster. Alternating current susceptibility data of the cluster show strong frequency dependence of both the real and imaginary parts of susceptibility χ‘ and χ‘ ‘ below 5 K. Moreover, the calculated relaxation time, τ0 = 1.2 × 10-7 s, and the energy barrier, ΔE = 25 K, are consistent with the single-molecule magnetic behavior of 1

Synthesis, Structures, and Magnetic Behavior of a Series of Copper(II) Azide Polymers of Cu₄ Building Clusters and Isolation of a New Hemiaminal Ether as the Metal Complex

Four new neutral copper azido polymers, [Cu4(N3)8(L1)2]n (1), [Cu4(N3)8(L2)2]n (2), [Cu4(N3)8(L3)2]n (3), and [Cu9(N3)18(L4)4]n (4) [L1−4 are formed in situ by reacting pyridine-2-carboxaldehyde with 2-[2-(methylamino)ethyl]pyridine (mapy, L1), N,N-dimethylethylenediamine (N,N-dmen, L2), N,N-diethylethylenediamine (N,N-deen, L3), and N,N,2,2-tetramethylpropanediamine (N,N,2,2-tmpn, L4)], have been synthesized by using 0.5 mol equiv of the chelating tridentate ligands with Cu(NO3)2·3H2O and an excess of NaN3. Single-crystal X-ray structures show that the basic unit of these complexes, especially 1−3, contains very similar CuII4 building blocks. The overall structure of 3 is two-dimensional, while the other three complexes are one-dimensional in nature. Complex 1 represents a unique example containing hemiaminal ether arrested by copper(II). Complexes 1 and 2 have a rare bridging azido pathway: both end-on and end-to-end bridging azides between a pair of CuII centers. Cryomagnetic susceptibility measurements over a wide range of temperature exhibit dominant ferromagnetic behavior in all four complexes. Density functional theory calculations (B3LYP functional) have been performed on complexes 1−3 to provide a qualitative theoretical interpretation of their overall ferromagnetic behavior

Chiral Molecular Ferromagnets Based on Copper(II) Polymers with End-On Azido Bridges

Two homochiral two-dimensional brick-wall complexes with only end-on azido bridges, [Cu3((R)-phea)2(N3)6]n (1) and [Cu3((S)-phea)2(N3)6]n (2) (phea = 1-phenylethylamine), have been synthesized and structurally characterized. Magnetic studies show that both complexes are chiral ferromagnets with the magnetic transition temperature at 5.5 K

Synthesis, Structures, and Magnetic Behavior of a Series of Copper(II) Azide Polymers of Cu₄ Building Clusters and Isolation of a New Hemiaminal Ether as the Metal Complex

Four new neutral copper azido polymers, [Cu4(N3)8(L1)2]n (1), [Cu4(N3)8(L2)2]n (2), [Cu4(N3)8(L3)2]n (3), and [Cu9(N3)18(L4)4]n (4) [L1−4 are formed in situ by reacting pyridine-2-carboxaldehyde with 2-[2-(methylamino)ethyl]pyridine (mapy, L1), N,N-dimethylethylenediamine (N,N-dmen, L2), N,N-diethylethylenediamine (N,N-deen, L3), and N,N,2,2-tetramethylpropanediamine (N,N,2,2-tmpn, L4)], have been synthesized by using 0.5 mol equiv of the chelating tridentate ligands with Cu(NO3)2·3H2O and an excess of NaN3. Single-crystal X-ray structures show that the basic unit of these complexes, especially 1−3, contains very similar CuII4 building blocks. The overall structure of 3 is two-dimensional, while the other three complexes are one-dimensional in nature. Complex 1 represents a unique example containing hemiaminal ether arrested by copper(II). Complexes 1 and 2 have a rare bridging azido pathway: both end-on and end-to-end bridging azides between a pair of CuII centers. Cryomagnetic susceptibility measurements over a wide range of temperature exhibit dominant ferromagnetic behavior in all four complexes. Density functional theory calculations (B3LYP functional) have been performed on complexes 1−3 to provide a qualitative theoretical interpretation of their overall ferromagnetic behavior

Chiral Molecular Ferromagnets Based on Copper(II) Polymers with End-On Azido Bridges

Two homochiral two-dimensional brick-wall complexes with only end-on azido bridges, [Cu3((R)-phea)2(N3)6]n (1) and [Cu3((S)-phea)2(N3)6]n (2) (phea = 1-phenylethylamine), have been synthesized and structurally characterized. Magnetic studies show that both complexes are chiral ferromagnets with the magnetic transition temperature at 5.5 K

Chiral Molecular Ferromagnets Based on Copper(II) Polymers with End-On Azido Bridges

Two homochiral two-dimensional brick-wall complexes with only end-on azido bridges, [Cu3((R)-phea)2(N3)6]n (1) and [Cu3((S)-phea)2(N3)6]n (2) (phea = 1-phenylethylamine), have been synthesized and structurally characterized. Magnetic studies show that both complexes are chiral ferromagnets with the magnetic transition temperature at 5.5 K

Syntheses, Structures, and Magnetic Properties of Five Novel Octacyanometallate-Based Lanthanide Complexes with Helical Chains

The reactions of octacyanometallates [M(CN)8]3‑ (M = Mo, W) and lanthanide ions Ln3+ (Ln = Pr, Sm, Eu) through the solution diffusion method in the presence of chelated aromatic ligands 1,10-phenanthroline (phen) or 3,4,7,8-tetramethyl-1,10-phenanthroline (tmphen) have yielded five new [M(CN)8]3–-based bimetallic complexes with helical structures: [Ln(phen)2(H2O)Mo(CN)8]2[(n-C4H9)4N](NO3)·2CH3CN·4H2O [Ln = Sm(1), Eu(2)], [Sm(tmphen)2(DMF)2][W(CN)8]·2H2O (3), and [Pr(tmphen)(DMF)5][M(CN)8]·DMF·2H2O [M = Mo(4), W(5)]. The Ln3+ centers are linked alternately by [M(CN)8]3– units through two trans V-shaped cyano groups to form the left- and right-handed helical chains running along the screw axis. Magnetic measurements revealed the presence of an antiferromagnetic interaction between metal centers in 4 and 5

Syntheses, Structures, and Magnetic Properties of Five Novel Octacyanometallate-Based Lanthanide Complexes with Helical Chains

The reactions of octacyanometallates [M(CN)8]3‑ (M = Mo, W) and lanthanide ions Ln3+ (Ln = Pr, Sm, Eu) through the solution diffusion method in the presence of chelated aromatic ligands 1,10-phenanthroline (phen) or 3,4,7,8-tetramethyl-1,10-phenanthroline (tmphen) have yielded five new [M(CN)8]3–-based bimetallic complexes with helical structures: [Ln(phen)2(H2O)Mo(CN)8]2[(n-C4H9)4N](NO3)·2CH3CN·4H2O [Ln = Sm(1), Eu(2)], [Sm(tmphen)2(DMF)2][W(CN)8]·2H2O (3), and [Pr(tmphen)(DMF)5][M(CN)8]·DMF·2H2O [M = Mo(4), W(5)]. The Ln3+ centers are linked alternately by [M(CN)8]3– units through two trans V-shaped cyano groups to form the left- and right-handed helical chains running along the screw axis. Magnetic measurements revealed the presence of an antiferromagnetic interaction between metal centers in 4 and 5

Syntheses, Structures, and Magnetic Properties of Five Novel Octacyanometallate-Based Lanthanide Complexes with Helical Chains

The reactions of octacyanometallates [M(CN)8]3‑ (M = Mo, W) and lanthanide ions Ln3+ (Ln = Pr, Sm, Eu) through the solution diffusion method in the presence of chelated aromatic ligands 1,10-phenanthroline (phen) or 3,4,7,8-tetramethyl-1,10-phenanthroline (tmphen) have yielded five new [M(CN)8]3–-based bimetallic complexes with helical structures: [Ln(phen)2(H2O)Mo(CN)8]2[(n-C4H9)4N](NO3)·2CH3CN·4H2O [Ln = Sm(1), Eu(2)], [Sm(tmphen)2(DMF)2][W(CN)8]·2H2O (3), and [Pr(tmphen)(DMF)5][M(CN)8]·DMF·2H2O [M = Mo(4), W(5)]. The Ln3+ centers are linked alternately by [M(CN)8]3– units through two trans V-shaped cyano groups to form the left- and right-handed helical chains running along the screw axis. Magnetic measurements revealed the presence of an antiferromagnetic interaction between metal centers in 4 and 5