Effect of Ligand Spacer on Metallosupramolecular Architectures: From a Dinuclear Copper(II) Double Helicate to a Tetranuclear Copper(II) Complex

Halder, Partha; Banerjee, Priya R.; Zangrando, Ennio; Paine, Tapan Kanti

doi:10.1002/ejic.200800817

Cited by 10 publications

(6 citation statements)

References 61 publications

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“…The asymmetric unit of the compound contains two independent molecules (A and B). All the bond lengths in the compounds are within normal ranges [ 10 ], and are comparable to those of the similar Schiff bases [11][12][13]. The C8-N1 and C21-N2 bond lengths confirm them as double bonds.…”

Section: Crystal Data For the Compoundssupporting

confidence: 59%

CHARACTERIZATION AND CRYSTAL STRUCTURES OF 5-BROMO-2-METHOXY-4-(p-TOLYLIMINOMETHYL)PHENOL AND 2-BROMO-6-[(6-METHYLPYRIDIN-2-YLIMINO)METHYL]PHENOL

2015

JSC

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Two bromo-substituted Schiff bases 5-bromo-2-methoxy-4-(p-tolyliminomethyl)phenol (1) and 2-bromo-6-[(6-methylpyridin-2-ylimino)methyl]phenol (2) are prepared and characterized by elemental analysis, 1 H and 13 C NMR, and single crystal X-ray diffraction. Compound 1 crystallizes in the triclinic space group 1 P with unit cell dimensions a = 6.228(1) Å, b = 10.929(2) Å, c = 21.312(2) Å, D = 104.230(2)°, E = 91.780(2)°, J = 90.890(2)°, V = = 1405.0(4) Å 3 , Z = 4, R 1 = 0.0359, and wR 2 = 0.0830. Compound 2 crystallizes in the monoclinic space group P 2 1 /c with unit cell dimensions a = 8.180(2) Å, b = 12.011(3) Å, c = 12.843(3) Å, E = 106.263(2)°, V = 1211.4(4) Å 3 , Z = 4, R 1 = 0.0364, and wR 2 = 0.0889. X-ray diffraction indicates that the Schiff base molecules of the compounds display trans configuration with respect to the C=N double bonds. The crystal structures of the compounds are stabilized by hydrogen bonds and weak SѱS interactions.

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Section: Crystal Data For the Compoundssupporting

confidence: 59%

CHARACTERIZATION AND CRYSTAL STRUCTURES OF 5-BROMO-2-METHOXY-4-(p-TOLYLIMINOMETHYL)PHENOL AND 2-BROMO-6-[(6-METHYLPYRIDIN-2-YLIMINO)METHYL]PHENOL

2015

JSC

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“…Stabilization of the helicate conforma-tion over the mesocate by the establishment of intramolecular interactions has been foundi nC u II bimetallic complexes, in which the helical folding of the ligandsa llows face-to-face stacking between cofaciala romatic rings of different strandso f ligands. [22,23] This interaction is less probablei nt he meso form for whicht he aromatic planeso fd ifferent ligandsa re not parallel. [24][25][26] In the same way,A lbrecht et al recently reported [27] about the importance of weakn oncovalent interactions in hierarchically assembled titanium triscatecholate helicates, for which the lithium-dependent formation of dimerich elicates is enthalpically favored by London dispersion forces established between hydrophobic chains of the ligands.…”

Section: Introductionmentioning

confidence: 97%

“…In terms of supramolecularity, other components of molecular information can be invoked for the construction of more complex architectures. Stabilization of the helicate conformation over the mesocate by the establishment of intramolecular interactions has been found in Cu II bimetallic complexes, in which the helical folding of the ligands allows face‐to‐face stacking between cofacial aromatic rings of different strands of ligands . This interaction is less probable in the meso form for which the aromatic planes of different ligands are not parallel .…”

Section: Introductionmentioning

confidence: 99%

Steric and Electronic Factors Affecting the Conformation of Bimetallic Cu^I Complexes: Effect of the Aliphatic Spacer of Tetracoordinating Schiff‐Base Ligands

Díaz

Llanos

Arce

et al. 2018

Chemistry A European J

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A family of six homoleptic [Cu (L )] (ClO ) and six heteroleptic [Cu (L )(PPh ) ] (ClO ) bimetallic complexes, in which L are bis-Schiff base ligands with alkyl spacers of variable length (n=2-7 -CH -), were prepared to evaluate the role of the spacer on the formation of helicates or mesocates. In the homoleptic series, spectroscopic and theoretical studies indicate that preferences for a conformation are based on energetic parameters, mainly, the establishment of noncovalent interactions. The odd-even nature of the spacers preconditions the superposition of the aromatic rings to allow the juxtaposition necessary for noncovalent interactions, whereas the increase of the length reduces the strength of such interactions. Consequently, complexes with even-spacers of short length were identified as helicates in solution, [Cu (L )] (n=2, 4). Complexes [Cu (L )] (n=3-7) dissociate in solution to produce the monometallic complexes in equilibrium, [Cu (L )] . The stability of the bimetallic species is discussed in terms of their conformations. The set of heteroleptic complexes was prepared to evaluate the reach of the "odd-even rule" in the solid, which is based on the "zig-zag" arrangements of the spacers. Based on crystallographic information, "S-" and "C"-type conformations of L are related to even and odd spacers, respectively. This trend is considered in addition to other factors to explain preferences for either a mesocate or helicate conformation in the homoleptic series.

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“…It is evident that the greater flexibility of the ligand spacer supports the formation of high nuclearity clusters as observed for the tetranuclear copper(II) derivative built up by bis-(iminophenolato) spacers. 59 The rhomboid disposition of the metal ions is characterised by the Ag(1)-Ag(2) and Ag(2)-Ag(1¢) distances (i.e., metal ions bound by the ligand connector) of 6.592(2) and 8.058(2) A ˚, respectively with intermetallic angles of 74.23 • (at Ag(1)) and 101.93 • (at Ag(2)), which lead to a globular arrangement of the complex (Fig. 6).…”

Section: Crystal Structuresmentioning

confidence: 99%

Self-assembly of silver(i) and bis-bidentate N,N-donor ligands: from a tetranuclear complex to coordination polymers

2009

Self Cite

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The supramolecular self-assembly structures of one tetranuclear silver(i) complex and three silver(i) coordination polymers derived from bis-bidentate imino-pyridine ligands and their reduced N-methyl derivatives are discussed. Six new ligands were synthesised, and the X-ray structural analysis of L(1), L(2) and L(5) with silver(i) ions indicated the formation of 1D coordination polymers, namely {[AgL(1)]BF(4)}(n) (1), {[AgL(2)]ClO(4)}(n) (2), and {[AgL(5)]ClO(4).H(2)O}(n) (5), whereas ligand L(4) led to a tetranuclear complex {[AgL(4)]ClO(4)}(4) (4). L(1) is the Schiff-base derived from the condensation of alpha,alpha'-diamino-m-xylene and pyridine-2-carboxaldehyde and L(4) that resulting from the reaction of 2-(4-aminophenyl)ethylamine with 6-methyl-pyridine-2-carboxaldehyde, while L(2) and L(5) are the reduced N-methyl derivatives. The structural determination shows achiral syndiotactic polymers for 1 and chiral isotactic for 2 and 5. The 1D coordination chains of 1 are stabilised by intramolecular pi-pi stacking interactions between the phenyl ring of a spacer with the pyridine of a symmetry related adjacent ligand, while the crystal packing of 5 show inter-chain pi-pi interactions. Compound 4 comprises discrete tetranuclear [AgL(4)](4)(4+) complex cations and the rhomboid disposition of the metal ions leads to a globular arrangement of the silver(i) complex. The results provide an insight about the effect of ligand spacer length and flexibility in stabilising the metallo-supramolecular architecture.

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Effect of Ligand Spacer on Metallosupramolecular Architectures: From a Dinuclear Copper(II) Double Helicate to a Tetranuclear Copper(II) Complex

Cited by 10 publications

References 61 publications

CHARACTERIZATION AND CRYSTAL STRUCTURES OF 5-BROMO-2-METHOXY-4-(p-TOLYLIMINOMETHYL)PHENOL AND 2-BROMO-6-[(6-METHYLPYRIDIN-2-YLIMINO)METHYL]PHENOL

CHARACTERIZATION AND CRYSTAL STRUCTURES OF 5-BROMO-2-METHOXY-4-(p-TOLYLIMINOMETHYL)PHENOL AND 2-BROMO-6-[(6-METHYLPYRIDIN-2-YLIMINO)METHYL]PHENOL

Steric and Electronic Factors Affecting the Conformation of Bimetallic Cu^I Complexes: Effect of the Aliphatic Spacer of Tetracoordinating Schiff‐Base Ligands

Self-assembly of silver(i) and bis-bidentate N,N-donor ligands: from a tetranuclear complex to coordination polymers

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Effect of Ligand Spacer on Metallosupramolecular Architectures: From a Dinuclear Copper(II) Double Helicate to a Tetranuclear Copper(II) Complex

Cited by 10 publications

References 61 publications

CHARACTERIZATION AND CRYSTAL STRUCTURES OF 5-BROMO-2-METHOXY-4-(p-TOLYLIMINOMETHYL)PHENOL AND 2-BROMO-6-[(6-METHYLPYRIDIN-2-YLIMINO)METHYL]PHENOL

CHARACTERIZATION AND CRYSTAL STRUCTURES OF 5-BROMO-2-METHOXY-4-(p-TOLYLIMINOMETHYL)PHENOL AND 2-BROMO-6-[(6-METHYLPYRIDIN-2-YLIMINO)METHYL]PHENOL

Steric and Electronic Factors Affecting the Conformation of Bimetallic CuI Complexes: Effect of the Aliphatic Spacer of Tetracoordinating Schiff‐Base Ligands

Self-assembly of silver(i) and bis-bidentate N,N-donor ligands: from a tetranuclear complex to coordination polymers

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Steric and Electronic Factors Affecting the Conformation of Bimetallic Cu^I Complexes: Effect of the Aliphatic Spacer of Tetracoordinating Schiff‐Base Ligands