AI Article Synopsis
- This study investigates the magnetic exchange interactions in two dicopper complexes with different ligands (azaindole for complex A and pyrazole for complex B) using density functional theory.
- Despite the similar coordination environments, the magnetic properties of the two complexes are found to be opposite—complex A exhibits weak ferromagnetic coupling, while complex B shows strong antiferromagnetic coupling.
- The differences in their magnetic behaviors are attributed to the interactions between the bridging ligands, with complex A's properties arising from weak countercomplementary interactions, and complex B's strong coupling resulting from complementary interactions.
Article Abstract
The mechanisms of magnetic exchange interactions in two heterobridged mu-hydroxyl-mu-X dicopper complexes A and B (X = azaindole for A and X = pyrazole for B) are investigated by the calculations based on density functional theory combined with the broken-symmetry approach (DFT-BS). It is found that although the coordination circumstances of the copper centers in the two complexes are very similar, the magnetic magnitudes and signs are diametrically opposed. By the theoretical analyses of magnetic orbital interaction and spin distribution, it is indicated that the difference between the magnetic properties of the two complexes is due to the distinction of orbital interaction of two bridge ligands. Namely, the weak ferromagnetic coupling for complex A arises from the orbital countercomplementarity of the hydroxo and azaindole bridges while the strong antiferromagnetic coupling for complex B arises from the orbital complementarity of the hydroxo and pyrazolato bridges.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1021/jp8044252 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Solution Structure and Dynamics of Hf-Al and Hf-Zn Heterobimetallic Adducts Mimicking Relevant Intermediates in Chain Transfer Reactions.
Inorg Chem
May 2024
Department of Chemistry, Biology and Biotechnology and CIRCC, University of Perugia and CIRCC, Via Elce di Sotto 8, 06123 Perugia, Italy.
Cationic cyclometalated hafnocenes [CpCpHf][B(CF)] () and [CpCpHf][B(CF)] ( and ) were synthesized from the corresponding [(Cp)HfMe][B(CF)] () and [(Cp)HfMe][B(CF)] () complexes via C-H activation. , , and , mimicking a propagating M-polymeryl species (M = transition metal) with or without a β-methyl branch on the metalated chains, serve to investigate whether and how the nature of the last inserted olefin molecules changes the structure, stability, and reactivity of the corresponding heterobimetallic complexes, formed in the presence of aluminum- or zinc-alkyl chain transfer agents (CTAs), which are considered relevant intermediates in coordinative chain transfer polymerization (CCTP) and chain shuttling polymerization (CSP) technologies. NMR and DFT data indicate no major structural difference between the resulting heterobridged complexes, all characterized by the presence of multiple α-agostic interactions.
View Article and Find Full Text PDFInterception of Elusive Cationic Hf-Al and Hf-Zn Heterobimetallic Adducts with Mixed Alkyl Bridges Featuring Multiple Agostic Interactions.
Chemistry
March 2020
Dipartimento di Chimica, Biologia e Biotecnologie and CIRCC, Università degli Studi di Perugia, Via Elce di Sotto 8, 06123, Perugia, Italy.
Heterobimetallic complexes with inequivalent bridging alkyl chains are very often invoked as key intermediates in many catalytic processes, yet their interception and structural characterization are lacking. Such complexes have been prepared from reactions of the cationic cyclometalated hafnocene [Cp Cp Hf][B(C F ) ] (1) with main group metal alkyls to afford the corresponding hetero-bridged cationic products, [Cp Cp Hf(μ-R)E(R) ][B(C F ) ] (E=Al or Zn; R=Me, Et, or iBu). NMR and DFT studies demonstrate that both bridging alkyls establish agostic interactions with Hf, which are appreciably stronger for ethyl rather than methyl groups.
View Article and Find Full Text PDFStepwise formation of a pentanuclear Ni4Cu heterometallic complex exhibiting a vertex-sharing defective double-cubane core and diphenoxo- and phenoxo/azide bridging groups: a magnetostructural and DFT theoretical study.
Inorg Chem
April 2013
Department of Chemistry, Visva Bharati University, Santiniketan 731 235, India.
Sequential reaction of a N5O3 octadentate tripodal ligand with Ni(2+) and subsequently with Cu(2+) and azide ligand afforded the first example of a heterobridged (phenoxo/μ(1,1)-azido) pentanuclear heterometallic (Ni4Cu) compound, which exhibits a centrosymmetric vertex-sharing defective double-cubane structure. The study of the magnetic properties reveals that the compound shows ferromagnetic interaction interactions, leading to an S = 9/2 spin ground state. Density functional theory calculations on the X-ray structure and model compounds predict ferromagnetic interactions through the magnetic exchange pathways involving each couple of metal ions.
View Article and Find Full Text PDFTouching the upper limit for ferromagnetic interactions in hetero-bridged dinuclear [Cu2(II)] complexes using a novel N5-dinucleating ligand bearing an endogenous monoatomic amido(R-NH(-))-bridging group.
Chem Commun (Camb)
January 2012
Departamento de Química Inorgánica, Facultad de Ciencias, Universidad de Granada, Avda de Fuentenueva s/n, 18002-Granada, Spain.
A novel N(5)-dinucleating ligand 4-amino-3,5-bis(bipyridine-2-yl)-1,2,4-triazole allows the preparation for the first time, and under mild conditions, of single and mixed amido(R-NH(-))-bridged copper(II) complexes, the latter exhibiting very strong ferromagnetic coupling.
View Article and Find Full Text PDFHeterobridged dinuclear, tetranuclear, dinuclear-based 1-d, and heptanuclear-based 1-D complexes of copper(II) derived from a dinucleating ligand: syntheses, structures, magnetochemistry, spectroscopy, and catecholase activity.
Inorg Chem
August 2011
Department of Chemistry, University of Calcutta, 92 A. P. C. Road, Kolkata 700 009, India.
The work in this paper presents syntheses, characterization, crystal structures, variable-temperature/field magnetic properties, catecholase activity, and electrospray ionization mass spectroscopic (ESI-MS positive) study of five copper(II) complexes of composition [Cu(II)(2)L(μ(1,1)-NO(3))(H(2)O)(NO(3))](NO(3)) (1), [{Cu(II)(2)L(μ-OH)(H(2)O)}(μ-ClO(4))](n)(ClO(4))(n) (2), [{Cu(II)(2)L(NCS)(2)}(μ(1,3)-NCS)](n) (3), [{Cu(II)(2)L(μ(1,1)-N(3))(ClO(4))}(2)(μ(1,3)-N(3))(2)] (4), and [{Cu(II)(2)L(μ-OH)}{Cu(II)(2)L(μ(1,1)-N(3))}{Cu(II)(μ(1,1)-N(3))(4)(dmf)}{Cu(II)(2)(μ(1,1)-N(3))(2)(N(3))(4)}](n)·ndmf (5), derived from a new compartmental ligand 2,6-bis[N-(2-pyridylethyl)formidoyl]-4-ethylphenol, which is the 1:2 condensation product of 4-ethyl-2,6-diformylphenol and 2-(2-aminoethyl)pyridine. The title compounds are either of the following nuclearities/topologies: dinuclear (1), dinuclear-based one-dimensional (2 and 3), tetranuclear (4), and heptanuclear-based one-dimensional (5). The bridging moieties in 1-5 are as follows: μ-phenoxo-μ(1,1)-nitrate (1), μ-phenoxo-μ-hydroxo and μ-perchlorate (2), μ-phenoxo and μ(1,3)-thiocyanate (3), μ-phenoxo-μ(1,1)-azide and μ(1,3)-azide (4), μ-phenoxo-μ-hydroxo, μ-phenoxo-μ(1,1)-azide, and μ(1,1)-azide (5).
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!