A new end-to-end azido double-bridged copper(II) complex [Cu(2)L(2)(N(3))2] (1) was synthesized and characterized (L=1,1,1-trifluoro-7-(dimethylamino)-4-methyl-5-aza-3-hepten-2-onato). Despite the rather long Cu-Cu distance (5.105(1) A), the magnetic interaction is ferromagnetic with J= +16 cm(-1) (H=-JS(1)S(2)), a value that has been confirmed by DFT and high-level correlated ab initio calculations. The spin distribution was studied by using the results from polarized neutron diffraction. This is the first such study on an end-to-end system. The experimental spin density was found to be localized mainly on the copper(II) ions, with a small degree of delocalization on the ligand (L) and terminal azido nitrogens. There was zero delocalization on the central nitrogen, in agreement with DFT calculations. Such a picture corresponds to an important contribution of the d(x2-y2) orbital and a small population of the d(z2) orbital, in agreement with our calculations. Based on a correlated wavefunction analysis, the ferromagnetic behavior results from a dominant double spin polarization contribution and vanishingly small ionic forms.
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http://dx.doi.org/10.1002/chem.200601253 | DOI Listing |
Three new zinc(II) complexes, [Zn3(μ2-η1:η1-OAc)2(μ2-η2:η0-OAc)2L2] (1), [Zn3(μ2-η1:η1-OAc)2(μ1,1-N3)(N3)L2] (2), [Zn2(μ1,3-N3)(N3)(H2O)L2] (3), with the Schiff base ligand 4-chloro-2-(((2-(pyrrolidin-1-yl)ethyl)imino)methyl)phenol (HL) have been synthesized and characterized by elemental analysis, IR and UV-Vis spectroscopic studies. Crystal structures of the complexes were confirmed by single crystal X-ray diffraction. Complex 1 is a bidentate acetato, monoatomic bridging acetato, and phenolato co-bridged trinuclear zinc compound.
View Article and Find Full Text PDFActa Crystallogr C Struct Chem
August 2022
Leiden Institute of Chemistry, Leiden University, PO Box 9502, 2300 RA Leiden, The Netherlands.
The title metal-organic polymer, catena-poly[[(5,5'-dimethyl-2,2'-bipyridine-κN,N')iron(II)]-di-μ-azido-κN:N-[(5,5'-dimethyl-2,2'-bipyridine-κN,N')iron(II)]-di-μ-azido-κN:N], [Fe(N)(CHN)], features alternating μ-1,1 (end-on mode of coordination) and μ-1,3 (end-to-end mode of coordination) double azide bridges, forming chains running in the [100] direction. The octahedral coordination geometry around the Fe centre is completed by a bidentate 5,5'-dimethyl-2,2'-bipyridine ligand. Two polymorphs for this compound were obtained from the crude reaction product, the first in the space group P-1 and the other in P2/c.
View Article and Find Full Text PDFACS Omega
July 2022
Department of Chemistry, Prabhat Kumar College, Contai, Purba Medinipur, Contai 721404, India.
A new versatile azide-bridged polymeric Cu(II) complex, namely, [Cu(L)(μ-N)] (), was synthesized utilizing an N,N,O-donor piperidine-based Schiff base ligand ()-4-bromo-2-((2-(-1-yl)imino)methyl)phenol (), obtained the condensation reaction of 1-(2-aminoethyl) piperidine and 5-bromo salicylaldehyde. The single-crystal X-ray diffraction analysis reveals that complex consists of an end-to-end azido-bridged polymeric network, which is further rationalized with the help of a density functional theory (DFT) study. After routine characterization with a range of physicochemical studies, complex is exploited to evaluate its biomedical potential.
View Article and Find Full Text PDFJ Phys Chem Lett
June 2020
Department of Chemistry, Tulane University, New Orleans, Louisiana 70118, United States.
We used relaxation-assisted two-dimensional infrared spectroscopy to study the temperature dependence (10-295 K) of end-to-end energy transport across end-decorated PEG oligomers of various chain lengths. The excess energy was introduced by exciting the azido end-group stretching mode at 2100 cm (tag); the transport was recorded by observing the asymmetric C═O stretching mode of the succinimide ester end group at 1740 cm. The overall transport involves diffusive steps at the end groups and a ballistic step through the PEG chain.
View Article and Find Full Text PDFInorg Chem
January 2020
Institute of Problems of Chemical Physics IPCP RAS, Chernogolovka 142432 , Russia.
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