Novel Diazamesocyclic Ligands Functionalized with Pyridyl Donor Group(s) − Synthesis, Crystal Structures, and Properties of Their Copper(II) Complexes

Abstract

Two novel diazamesocyclic ligands based on l,5-diazacyclooctane (DACO) and functionalized with additional pyridyl donor groups, namely 1,5-bis(2-pyridylmethyl)-1,5-diazacyclooctane (L 1 ) and 1-(2-pyridylmethyl)-1,5-diazacyclooctane (L 2 ), have been synthesized and characterized, as have their Cu II complexes. Crystal structure analyses revealed that with Cu(ClO 4 ) 2 L 1 forms a five-coordinate mononuclear complex [Cu II L 1 Cl]ClO 4 (1), whereas L 2 forms a µ-Cl − -bridged dinuclear complex [Cu II (L 2 )Cl] 2 (ClO 4 ) 2 (2). Furthermore, it has been found that the apical chloride anion of 1 may be easily exchanged by azide anion, forming the mononuclear complex [Cu II L 1 (N 3 )]ClO 4 (3). There is a notable difference between 3 and 1 in that 3 forms a quasi-two-dimensional network through intermolecular C−H···O hydrogen bonds and π−π stacking interactions. Each Cu II center in the three com-

A Novel Bis Tridentate Bipyridine Carboxamide Ligand and Its Complexation to Copper(II): Synthesis, Structure, and Magnetism

“…SP I compounds can show both ferromagnetic or antiferromagnetic coupling constants, depending on the nature of the terminal ligands. There are seven SP I compounds with ferromagnetic coupling reported to date in the chemical literature . The J 2 value obtained for the [Cu 2 (L 1 )Cl 2 ] 2 dimer 2 is consistent with the 90° angle rule that the coupling is ferromagnetic for the φ value near to 90°.…”

“…In this respect, complex 2 presents J 2 values which are due to small structural deviations from the ideal squared Cu 2 Cl 2 core that are consistent with the molecular structure determined for 2 . Examples of planar copper dimers that have been magnetically characterized are still relatively scarce in the chemical literature. 10e,,,, To the best of our knowledge, this is the first example of a dimerized bis dinuclear copper(II) complex that displays ferromagnetic coupling interactions between the Cu(μ-Cl) 2 Cu dimers and antiferromagnetic coupling interactions between the Cu II centers within each half of the dimerized unit. A detailed search of the literature revealed one other example of a bis dinuclear copper(II) complex assembled from four salen-type ligands .…”

A Novel Bis Tridentate Bipyridine Carboxamide Ligand and Its Complexation to Copper(II): Synthesis, Structure, and Magnetism

“…SP I compounds can show both ferromagnetic or antiferromagnetic coupling constants, depending on the nature of the terminal ligands. There are seven SP I compounds with ferromagnetic coupling reported to date in the chemical literature . The J 2 value obtained for the [Cu 2 (L 1 )Cl 2 ] 2 dimer 2 is consistent with the 90° angle rule that the coupling is ferromagnetic for the φ value near to 90°.…”

“…In this respect, complex 2 presents J 2 values which are due to small structural deviations from the ideal squared Cu 2 Cl 2 core that are consistent with the molecular structure determined for 2 . Examples of planar copper dimers that have been magnetically characterized are still relatively scarce in the chemical literature. 10e,,,, To the best of our knowledge, this is the first example of a dimerized bis dinuclear copper(II) complex that displays ferromagnetic coupling interactions between the Cu(μ-Cl) 2 Cu dimers and antiferromagnetic coupling interactions between the Cu II centers within each half of the dimerized unit. A detailed search of the literature revealed one other example of a bis dinuclear copper(II) complex assembled from four salen-type ligands .…”

Mimicking the Cu Active Site of Lytic Polysaccharide Monooxygenase Using Monoanionic Tridentate N-Donor Ligands

“…Crystalline samples that were suitable for X-ray diffraction were obtained and revealed the products to be L 1 CuCl and L 2 CuCl (Figure ). In the solid state, L 2 CuCl exists as a dimer composed of two L 2 CuCl units where the Cl from one unit has a weak interaction in the axial position of the Cu in the other unit (2.7025(9) and 2.7464(9) Å), a motif seen in other Cu­(II)–halide complexes supported by tridentate ligands. ,,− On the other hand, L 1 CuCl does not exhibit the same phenomenon, remaining monomeric in the solid state, as seen in other similar Cu­(II)–halide complexes. ,,,, The bond lengths are comparable between the two complexes, but all of the bond lengths were slightly shorter in L 1 CuCl , and the geometry index values, τ 4 , of the metal centers are 0.37 and 0.31 for L 1 CuCl and L 2 CuCl , respectively, indicating moderate deviation from a square planar geometry. Compared to a known Cu­(II)–Cl structure of LPMO, the Cu–N and Cu–Cl distances are similar (Cu–N­(his): 2.0 Å on average in the LPMO structure and Cu–N­(pyridine, pyrazole): 1.99 and 2.03 Å on average in L 1 CuCl and L 2 CuCl , respectively; Cu–N­(NH 2 ): 2.2 Å in the LPMO structure and Cu–N­(NH): 1.93 and 1.95 in L 1 CuCl and L 2 CuCl , respectively; Cu–Cl 2.3 Å in the LPMO structure and 2.21 and 2.27 Å in L 1 CuCl and L 2 CuCl , respectively).…”

Cationic−anionic complexes of Cu( ii ) and Co( ii ) with N -scorpionate ligand – structure, spectroscopy, and catecholase activity

“…In the case of copper( ii ) complexes with tripodal tetradentate ligands, the coordination sphere around the copper( ii ) centre can possess a square-pyramidal or a trigonal–bipyramidal coordination mode, with the d-d absorption bands shifted to higher energy for the compounds with a square-pyramidal configuration compared to those with a trigonal–bipyramidal geometry. 33,47,48…”

A Novel Bis Tridentate Bipyridine Carboxamide Ligand and Its Complexation to Copper(II): Synthesis, Structure, and Magnetism

“…SP I compounds can show both ferromagnetic or antiferromagnetic coupling constants, depending on the nature of the terminal ligands. There are seven SP I compounds with ferromagnetic coupling reported to date in the chemical literature . The J 2 value obtained for the [Cu 2 (L 1 )Cl 2 ] 2 dimer 2 is consistent with the 90° angle rule that the coupling is ferromagnetic for the φ value near to 90°.…”

“…In this respect, complex 2 presents J 2 values which are due to small structural deviations from the ideal squared Cu 2 Cl 2 core that are consistent with the molecular structure determined for 2 . Examples of planar copper dimers that have been magnetically characterized are still relatively scarce in the chemical literature. 10e,,,, To the best of our knowledge, this is the first example of a dimerized bis dinuclear copper(II) complex that displays ferromagnetic coupling interactions between the Cu(μ-Cl) 2 Cu dimers and antiferromagnetic coupling interactions between the Cu II centers within each half of the dimerized unit. A detailed search of the literature revealed one other example of a bis dinuclear copper(II) complex assembled from four salen-type ligands .…”

Mimicking the Cu Active Site of Lytic Polysaccharide Monooxygenase Using Monoanionic Tridentate N-Donor Ligands

“…Crystalline samples that were suitable for X-ray diffraction were obtained and revealed the products to be L 1 CuCl and L 2 CuCl (Figure ). In the solid state, L 2 CuCl exists as a dimer composed of two L 2 CuCl units where the Cl from one unit has a weak interaction in the axial position of the Cu in the other unit (2.7025(9) and 2.7464(9) Å), a motif seen in other Cu­(II)–halide complexes supported by tridentate ligands. ,,− On the other hand, L 1 CuCl does not exhibit the same phenomenon, remaining monomeric in the solid state, as seen in other similar Cu­(II)–halide complexes. ,,,, The bond lengths are comparable between the two complexes, but all of the bond lengths were slightly shorter in L 1 CuCl , and the geometry index values, τ 4 , of the metal centers are 0.37 and 0.31 for L 1 CuCl and L 2 CuCl , respectively, indicating moderate deviation from a square planar geometry. Compared to a known Cu­(II)–Cl structure of LPMO, the Cu–N and Cu–Cl distances are similar (Cu–N­(his): 2.0 Å on average in the LPMO structure and Cu–N­(pyridine, pyrazole): 1.99 and 2.03 Å on average in L 1 CuCl and L 2 CuCl , respectively; Cu–N­(NH 2 ): 2.2 Å in the LPMO structure and Cu–N­(NH): 1.93 and 1.95 in L 1 CuCl and L 2 CuCl , respectively; Cu–Cl 2.3 Å in the LPMO structure and 2.21 and 2.27 Å in L 1 CuCl and L 2 CuCl , respectively).…”

Cationic−anionic complexes of Cu( ii ) and Co( ii ) with N -scorpionate ligand – structure, spectroscopy, and catecholase activity

“…In the case of copper( ii ) complexes with tripodal tetradentate ligands, the coordination sphere around the copper( ii ) centre can possess a square-pyramidal or a trigonal–bipyramidal coordination mode, with the d-d absorption bands shifted to higher energy for the compounds with a square-pyramidal configuration compared to those with a trigonal–bipyramidal geometry. 33,47,48…”

A Novel Bis Tridentate Bipyridine Carboxamide Ligand and Its Complexation to Copper(II): Synthesis, Structure, and Magnetism

“…SP I compounds can show both ferromagnetic or antiferromagnetic coupling constants, depending on the nature of the terminal ligands. There are seven SP I compounds with ferromagnetic coupling reported to date in the chemical literature . The J 2 value obtained for the [Cu 2 (L 1 )Cl 2 ] 2 dimer 2 is consistent with the 90° angle rule that the coupling is ferromagnetic for the φ value near to 90°.…”

“…In this respect, complex 2 presents J 2 values which are due to small structural deviations from the ideal squared Cu 2 Cl 2 core that are consistent with the molecular structure determined for 2 . Examples of planar copper dimers that have been magnetically characterized are still relatively scarce in the chemical literature. 10e,,,, To the best of our knowledge, this is the first example of a dimerized bis dinuclear copper(II) complex that displays ferromagnetic coupling interactions between the Cu(μ-Cl) 2 Cu dimers and antiferromagnetic coupling interactions between the Cu II centers within each half of the dimerized unit. A detailed search of the literature revealed one other example of a bis dinuclear copper(II) complex assembled from four salen-type ligands .…”

Mimicking the Cu Active Site of Lytic Polysaccharide Monooxygenase Using Monoanionic Tridentate N-Donor Ligands

“…Crystalline samples that were suitable for X-ray diffraction were obtained and revealed the products to be L 1 CuCl and L 2 CuCl (Figure ). In the solid state, L 2 CuCl exists as a dimer composed of two L 2 CuCl units where the Cl from one unit has a weak interaction in the axial position of the Cu in the other unit (2.7025(9) and 2.7464(9) Å), a motif seen in other Cu­(II)–halide complexes supported by tridentate ligands. ,,− On the other hand, L 1 CuCl does not exhibit the same phenomenon, remaining monomeric in the solid state, as seen in other similar Cu­(II)–halide complexes. ,,,, The bond lengths are comparable between the two complexes, but all of the bond lengths were slightly shorter in L 1 CuCl , and the geometry index values, τ 4 , of the metal centers are 0.37 and 0.31 for L 1 CuCl and L 2 CuCl , respectively, indicating moderate deviation from a square planar geometry. Compared to a known Cu­(II)–Cl structure of LPMO, the Cu–N and Cu–Cl distances are similar (Cu–N­(his): 2.0 Å on average in the LPMO structure and Cu–N­(pyridine, pyrazole): 1.99 and 2.03 Å on average in L 1 CuCl and L 2 CuCl , respectively; Cu–N­(NH 2 ): 2.2 Å in the LPMO structure and Cu–N­(NH): 1.93 and 1.95 in L 1 CuCl and L 2 CuCl , respectively; Cu–Cl 2.3 Å in the LPMO structure and 2.21 and 2.27 Å in L 1 CuCl and L 2 CuCl , respectively).…”

Cationic−anionic complexes of Cu( ii ) and Co( ii ) with N -scorpionate ligand – structure, spectroscopy, and catecholase activity

“…In the case of copper( ii ) complexes with tripodal tetradentate ligands, the coordination sphere around the copper( ii ) centre can possess a square-pyramidal or a trigonal–bipyramidal coordination mode, with the d-d absorption bands shifted to higher energy for the compounds with a square-pyramidal configuration compared to those with a trigonal–bipyramidal geometry. 33,47,48…”