Thiophenophane metal complexes IV. Effects from ligand changes outside the coordination sphere

1996 ◽  
Vol 74 (11) ◽  
pp. 2340-2348 ◽  
Author(s):  
C. Robert Lucas ◽  
Shuang Liu
Keyword(s):  
Magnetic Susceptibility ◽  
Variable Temperature ◽  
Cyclic Voltammograms ◽  
Ferromagnetic Coupling ◽  
X Ray ◽  
H Nmr ◽  
Variable Temperature Magnetic Susceptibility ◽  
Structural Differences ◽  
Coordination Spheres ◽  
Temperature Responses

Preparation of two thiophenophane polythioether macrocycles and 11 of their complexes of Cu(I), Cu(II), Ag(I), and Pd(II) is described. The single crystal X-ray structure of [(CuBr)2(L1)x is reported: space group Pcma, a = 8.7120(6), b = 10.7791(5), c = 12.0929(5) Å, Z = 2, Rf = 0.052, Rw = 0.036 for 521 reflections. Variable-temperature magnetic susceptibility measurements for [(CuCl2)2(L1)] and [(CuCl2)2(L2)] reveal weak antiferromagnetic and weak ferromagnetic coupling, respectively. Cyclic voltammograms of these compounds display two unequal waves in acetonitrile solvent but only one in nitromethane or dimethyl sulfoxide. 1H NMR spectra of {[(η-C3H5)Pd]2(L1)}{PF6}2 and {[(η-C3H5)Pd]2(L2)}{PF6}2 in various solvents show different temperature responses. These magnetic, electrochemical, and NMR effects are discussed in the light of structural differences at sites in the two ligands that are outside the coordination spheres. Key words: magnetic susceptibility, copper, thioether, electrochemistry.

Copper(II) complexes of open-chain thioether ligands terminated by salicylaldimine functionality*This article has a companion paper in this issue (doi: 10.1139/v11-081).

2011 ◽  
Vol 89 (10) ◽  
pp. 1190-1201 ◽  
Author(s):  
C. Robert Lucas ◽  
John M.D. Byrne ◽  
Julie L. Collins ◽  
Louise N. Dawe ◽  
David O. Miller
Keyword(s):  
Magnetic Susceptibility ◽  
Single Crystal ◽  
Variable Temperature ◽  
Companion Paper ◽  
Structural Studies ◽  
Binuclear Copper ◽  
Open Chain ◽  
X Ray ◽  
Variable Temperature Magnetic Susceptibility ◽  
Coordination Spheres

From 1,11-bis(salicylaldimine)-3,6,9-trithiaundecane (H2L1), 1,11-bis(salicylaldimine)-6-oxa-3,9-dithiaundecane (H2L2), and 1,8-bis(salicylaldimine)-3,6-dithiaundecane (H2L3), syntheses for [Cu(L1)]2 (I), Cu(L2)·CH3OH (II), Cu(L3) (III), [Cu(HL3)][CH3COO] (IV), [Cu(HL1-sal)]Cl2 (V), Cu4(L1)2Br4(H2O)2·2H2O (VI) and Cu2(L2)Br2·xH2O (VII) are described. Single crystal X-ray structural studies for I, III and VII are reported. Variable temperature magnetic susceptibility studies of I, VI and VII are discussed. The examination of VII represents the first magneto-structural study of a binuclear copper(II) species with NSO3Br coordination spheres. This study examines perturbation by one or more of the donor atoms so that none of the known magnetostructural models predicts the copper–copper coupling.

Manganese(II) Oxazolidine Nitroxide Chelates: Structure, Magnetism, and Redox Properties

2014 ◽  
Vol 67 (11) ◽  
pp. 1618 ◽  
Author(s):  
Ian A. Gass ◽  
Mousa Asadi ◽  
David W. Lupton ◽  
Boujemaa Moubaraki ◽  
Alan M. Bond ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Intramolecular Interaction ◽  
Variable Temperature ◽  
Field Measurements ◽  
X Ray Diffraction ◽  
Magnetic Susceptibility Data ◽  
X Ray ◽  
Susceptibility Data ◽  
Variable Temperature Magnetic Susceptibility ◽  
Radical Interaction

The mononuclear oxazolidine nitroxide complex [MnII(L•)2](ClO4)2 (1) (L•, 4-dimethyl-2,2-di(2-pyridyl)oxazolidine N-oxide) has been synthesized and investigated using single-crystal X-ray diffraction, variable-temperature magnetic susceptibility measurements, and electrochemistry. The structural analysis reveals bond lengths compatible with a linear L•–MnII–L• arrangement where the ligands are in the neutral ligand form and the central MnII ion is high spin (S = 5/2). Although analysis of the variable-temperature magnetic susceptibility data suggests a strong antiferromagnetic metal–radical interaction, the radical–radical intramolecular interaction could not be determined unambiguously from such fits. The resultant isolated S = 3/2 ground state is confirmed by low-temperature magnetization versus field measurements. Electrochemical studies reveal similar square schemes and redox intermediates to the previously reported analogues [FeII(L•)2][BF4]2 and [CoII(L•)2][NO3]2.

A new binuclear NiII complex with tetrafluorophthalate and 2,2′-bipyridine ligands: synthesis, crystal structure and magnetic properties

2019 ◽  
Vol 74 (11-12) ◽  
pp. 833-838 ◽  
Author(s):  
Jun-Xia Li ◽  
Zhong-Xiang Du ◽  
Xun Feng
Keyword(s):  
Variable Temperature ◽  
Ferromagnetic Coupling ◽  
X Ray Diffraction ◽  
Magnetic Susceptibility Data ◽  
X Ray ◽  
Susceptibility Data ◽  
Variable Temperature Magnetic Susceptibility ◽  
Niii Complex ◽  
Weak Ferromagnetic ◽  
Dinuclear Structure

AbstractA new NiII compound, [Ni2(tfpa)2(bipy)2(H2O)4] (1) with tetrafluorophthalate (tfpa2−) and 2,2′-bipyridine (abbreviated as bipy) ligands, has been synthesized and structurally characterized. The single-crystal X-ray diffraction analysis reveals that the tfpa2− anions act as bis-monodentate linkers connecting NiII centers to form the dinuclear structure of 1. The dimeric units are stabilized by intramolecular π–π stacking and are further connected into a layer through O–HLO hydrogen bonding. Variable-temperature magnetic susceptibility data in the 10–200 K temperature range indicate weak ferromagnetic coupling between the two NiII ions.

Dynamic stereoisomerization in inherently chiral bimetallic [2]catenanes

2015 ◽  
Vol 51 (27) ◽  
pp. 5840-5843 ◽  
Author(s):  
Thirumurugan Prakasam ◽  
Matteo Lusi ◽  
Elisa Nauha ◽  
John-Carl Olsen ◽  
Mohamadou Sy ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Variable Temperature ◽  
Redox Processes ◽  
Metal Translocation ◽  
X Ray ◽  
X Ray Crystallography ◽  
H Nmr ◽  
Inherently Chiral

Stereoisomerization and the unprecedented phenomenon of metal translocation in the absence of redox processes were probed in two inherently chiral bimetallic [2]catenanes by using a combination of variable-temperature 1H NMR and CD spectroscopies, X-ray crystallography, and DFT calculations.

Nature of the active silane alcoholysis catalyst in the RuwClx(CO)y(PMe3)z (w, x, y, z = 1 or 2) system; Ru2(µ-Cl)2Cl2(CO)4(PMe3)2 as a new catalyst for silane alcoholysis in a polar solvent

2001 ◽  
Vol 79 (5-6) ◽  
pp. 949-957 ◽  
Author(s):  
Mee-Kyung Chung ◽  
George Ferguson ◽  
Valerie Robertson ◽  
Marcel Schlaf
Keyword(s):  
Dynamic Behaviour ◽  
Polar Solvent ◽  
Variable Temperature ◽  
Model System ◽  
Dimeric Complex ◽  
X Ray ◽  
H Nmr ◽  
Nonpolar Solvents ◽  
Solid State Structures ◽  
Silane Alcoholysis

The dimeric complex Ru2(µ-Cl)2Cl2(CO)4(PMe3)2 (1) forms an active silane alcoholysis complex in the polar solvent N,N-dimethylamino-acetamide (DMA). The dynamic behaviour of 1 in DMF-d7 solution has been investigated by variable temperature (VT) 1H NMR. The solid state structures of 1 and cis,cis,trans-RuCl2(CO)2(PMe3)2 (3) have been determined by single crystal X-ray diffractometry. Using ethylene glycol - triethylsilane as a model system, the catalytic activity of 1 in DMA is compared to that of a series of known silane alcoholysis catalysts, including RhCl(PPh3)3, PdX2 (X = Cl-, OAc-), and cis,cis,trans-[IrH2S2L2]SbF6 (L = PPh3, S = THF). Complex 3 is not an active silane alcoholysis catalyst in this solvent, but is active in nonpolar solvents. Its structure and spectroscopic signature is, however, different from that of a previously reported catalyst of the same composition.Key words: silane alcoholysis, polar solvent, ruthenium catalyst.

scholarly journals [3.3]Dithia-bridged cyclophanes featuring a thienothiophene ring: synthesis, structures and conformational analysis

2009 ◽  
Vol 5 ◽  
Author(s):  
Sabir H Mashraqui ◽  
Yogesh Sanghvikar ◽  
Shailesh Ghadhigaonkar ◽  
Sukeerthi Kumar ◽  
Auke Meetsma ◽  
...  
Keyword(s):  
Conformational Analysis ◽  
Energy Minimization ◽  
Elevated Temperatures ◽  
Variable Temperature ◽  
Energy Difference ◽  
Nmr Analysis ◽  
Stable Conformation ◽  
X Ray ◽  
X Ray Crystallography ◽  
H Nmr

The synthesis of [3.3]dithia-bridged cyclophanes 7, 9 and 11 incorporating a fused heterocycle, thieno[2,3-b]thiophene is described. The structures are established by 1H NMR analysis and, in the case of 11, also by single crystal X-ray crystallography. Conformational analysis by variable temperature NMR suggests that cyclophanes 7, 9 and 11 exhibit conformationally rigid bridges and rings at least up to 130 °C. Energy minimization of 11 revealed anti -11 to be the most stable conformation. Although, the computed energy difference between the most stable conformation anti -11 and the next higher energy conformation syn-anti -11 is only 2.98 kJ/mol, it is intriguing that 11 does not exhibit thia-bridge inversion even at elevated temperatures.

Sign in / Sign up

Export Citation Format

Share Document