scholarly journals Solution-State Spin Crossover in a Family of [Fe(L)2(CH3CN)2](BF4)2 Complexes

2019 ◽  
Vol 5 (2) ◽  
pp. 22
Author(s):  
Benjamin Wilson ◽  
Hayley Scott ◽  
Rosanna Archer ◽  
Corine Mathonière ◽  
Rodolphe Clérac ◽  
...  
Keyword(s):  
Thermodynamic Parameters ◽  
General Formula ◽  
Spin Crossover ◽  
Variable Temperature ◽  
Spectroscopic Studies ◽  
Solution State ◽  
Uv Visible ◽  
State Spin

We report herein on five new Fe(II) complexes of general formula [Fe(L)2(NCCH3)2](BF4)2•xCH3CN (L = substituted 2-pyridylimine-based ligands). The influence of proximally located electron withdrawing groups (e.g., NO2, CN, CF3, Cl, Br) bound to coordinated pyridylimine ligands has been studied for the effect on spin crossover in their Fe(II) complexes. Variable-temperature UV-visible spectroscopic studies performed on complexes with more strongly electronegative ligand substituents revealed spin crossover (SCO) in the solution, and thermodynamic parameters associated with the spin crossover were estimated.

scholarly journals Solvent Effects on the Spin-Transition in a Series of Fe(II) Dinuclear Triple Helicate Compounds

Crystals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 376 ◽  
Author(s):  
Alexander Craze ◽  
Mohan Bhadbhade ◽  
Cameron Kepert ◽  
Leonard Lindoy ◽  
Christopher Marjo ◽  
...  
Keyword(s):  
Spin Crossover ◽  
Condensation Product ◽  
Variable Temperature ◽  
Spin Transition ◽  
Single Step ◽  
Spin Conversion ◽  
Dinuclear Iron ◽  
Solvent Molecules ◽  
State Spin ◽  
Triple Helicate

This work explores the effect of lattice solvent on the observed solid-state spin-transition of a previously reported dinuclear Fe(II) triple helicate series 1–3 of the general form [FeII2L3](BF4)4(CH3CN)n, where L is the Schiff base condensation product of imidazole-4-carbaldehyde with 4,4-diaminodiphenylmethane (L1), 4,4′-diaminodiphenyl sulfide (L2) and 4,4′-diaminodiphenyl ether (L3) respectively, and 1 is the complex when L = L1, 2 when L = L2 and 3 when L = L3 (Craze, A.R.; Sciortino, N.F.; Bhadbhade, M.M.; Kepert, C.J.; Marjo, C.E.; Li, F. Investigation of the Spin Crossover Properties of Three Dinuclear Fe(II) Triple Helicates by Variation of the Steric Nature of the Ligand Type. Inorganics. 2017, 5 (4), 62). Desolvation of 1 and 2 during measurement resulted not only in a decrease in T1/2 and completeness of spin-crossover (SCO) but also a change in the number of steps in the spin-profile. Compounds 1 and 2 were observed to change from a two-step 70% complete transition when fully solvated, to a single-step half complete transition upon desolvation. The average T1/2 value of the two-steps in the solvated materials was equivalent to the single T1/2 of the desolvated sample. Upon solvent loss, the magnetic profile of 3 experienced a transformation from a gradual SCO or weak antiferromagnetic interaction to a single half-complete spin-transition. Variable temperature single-crystal structures are presented and the effects of solvent molecules are also explored crystallographically and via a Hirshfeld surface analysis. The spin-transition profiles of 1–3 may provide further insight into previous discrepancies in dinuclear triple helicate SCO research reported by the laboratories of Hannon and Gütlich on analogous systems (Tuna, F.; Lees, M. R.; Clarkson, G. J.; Hannon, M. J. Readily Prepared Metallo-Supramolecular Triple Helicates Designed to Exhibit Spin-Crossover Behaviour. Chem. Eur. J. 2004, 10, 5737–5750 and Garcia, Y.; Grunert, C. M.; Reiman, S.; van Campenhoudt, O.; Gütlich, P. The Two-Step Spin Conversion in a Supramolecular Triple Helicate Dinuclear Iron(II) Complex Studied by Mössbauer Spectroscopy. Eur. J. Inorg. Chem. 2006, 3333–3339).

scholarly journals New Brightener for Zn-Fe Alloy Plating from Sulphate Bath

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
B. M. Praveen ◽  
T. V. Venkatesha
Keyword(s):  
Grain Size ◽  
Metal Ion ◽  
Condensation Product ◽  
Spectroscopic Studies ◽  
Sem Images ◽  
Alloy Electrodeposition ◽  
Fine Grained ◽  
Polarization Studies ◽  
Uv Visible ◽  
Sulphate Bath

Zn-Fe alloy electrodeposition was carried out in the presence of condensation product 2-{[(1E)-(3,4-dimethoxyphenyl)methylidene]amino}-3-hydroxypropanoic acid formed between veratraldehyde and serine in acid sulphate bath. Hull cell was used for optimizing the operating parameters and bath constituents. During deposition, the potential was shifted towards cathodic direction in the presence of addition agents and brightener. The polarization studies show that deposition taking place in basic bath and optimum bath was 1.08 and 1.15 V, respectively. Current efficiency and throwing power were reached around 85% and 26%, respectively. The SEM images of bright deposit indicated its fine-grained nature and appreciable reduction in the grain size. XRD studies have showed that the grain size of the deposit generated from optimum bath was 16 nm. UV-visible spectroscopic studies confirm the formation of complex between metal ion and brightener.

Structural and spectroscopic studies of transition metal nitrite complexes. VIII. Crystal structures and spectra of three pentanuclear species with stoichiometry [Ni5(N-substituted ethane-1,2-diamine)4(OH)2(NO2)8]

1981 ◽  
Vol 34 (10) ◽  
pp. 2139 ◽  
Author(s):  
AJ Finney ◽  
MA Hitchman ◽  
CL Raston ◽  
GL Rowbottom ◽  
AH White
Keyword(s):  
Transition Metal ◽  
Crystal Structures ◽  
General Formula ◽  
Infrared Spectra ◽  
Spectroscopic Studies ◽  
Molecular Structures ◽  
Structural Variations ◽  
Crystal And Molecular Structures

The preparation of a series of novel compounds of general formula [Ni5L4(NO2)8(OH)2] formed by ethane-1,2-diamine or one of five N-substituted ethane-1,2-diamines (L) is described. The crystal and molecular structures of the ethane-1,2-diamine, N,N'-diethylethane-1,2-diamine and N,N-dimethylethane-1,2-diamine complexes are reported. Each compound contains a planar, pentameric arrangement of nickel(II) ions, linked by bridging hydroxide and nitrite ligands. The details of the nitrite bridges differ among the complexes, causing differences in their electronic and infrared spectra. The structural variations are probably caused by the differing steric requirements of the amine substituents.

scholarly journals Synthesis and characterization of new complexes of Co+2 , Ni+2 , Cu+2 and Zn+2 with (Sodium acetate thio ) ethylene ligands

2013 ◽  
Vol 10 (3) ◽  
pp. 650-657
Author(s):  
Baghdad Science Journal
Keyword(s):  
Content Analysis ◽  
General Formula ◽  
Metal Content ◽  
Sodium Acetate ◽  
Magnetic Measurement ◽  
Synthesis And Characterization ◽  
Square Planar ◽  
Square Planar Complexes ◽  
Uv Visible

This research involves the preparation of new ligands 1,1,2,2- tetrakis (sodium acetate thio)ethylene(L1) and 1,1,2- tris(sodiumacetatethio) ethylene(L2), through the reaction of disodium thioglycolate) with tetra chloro ethylene or tri chloro ethylene in (1:4) or (1:3) moler ratio . Homodinucliar complexes of general formlu [M2(L1)] and [M2(L2)ClH2O] , when M= Co(II), Ni(II), Cu (II) and Zn(II) also mono nuclear complexes of general formula [M(L2)] . The prepared complexes were characterized using spectral method (UV/Visible/ IR) , metal content analysis , magnetic and atomic measurements . The spectral and magnetic measurement indicats that some complexes have tetrahedral or square planar complexes environtment .

A Newly Designed Cryostat for Absorption Spectroscopic Studies of Liquids, Solids, and the Interphases

1988 ◽  
Vol 42 (8) ◽  
pp. 1401-1404 ◽  
Author(s):  
J. C. Cornut ◽  
P. V. Huong ◽  
A. Graja ◽  
G. Daleau
Keyword(s):  
Solid State ◽  
Absorption Spectroscopy ◽  
Thermal Convection ◽  
Spectroscopic Studies ◽  
Sample Cell ◽  
Cold Stream ◽  
Uv Visible ◽  
Freezing Chamber

A double jacket cryostat based on thermal convection between a gaseous cold stream filled in a freezing chamber and the sample cell is described. This device is designed for absorption spectroscopy in the infrared and in the UV-visible regions for gases, liquids, liquefied gases, and solids, as well as for the transitions between these phases or between phases in the solid state, over the range 85 to 340 K, at variable thicknesses and under a pressure of up to 10 bars.

Solid-State Spin Crossover of Ni(II) in a Bioinspired N3S2Ligand Field

2011 ◽  
Vol 133 (15) ◽  
pp. 5644-5647 ◽  
Author(s):  
Huaibo Ma ◽  
Jeffrey L. Petersen ◽  
Victor G. Young ◽  
Gordon T. Yee ◽  
Michael P. Jensen
Keyword(s):  
Solid State ◽  
Spin Crossover ◽  
State Spin

scholarly journals Spectroscopic studies on the potassium 1-fluorobenzoyltrifluoroborate salt by using the FT-IR, Raman and UV–Visible spectra and DFT calculations

2020 ◽  
Vol 1204 ◽  
pp. 127534 ◽  
Author(s):  
Maximiliano A. Iramain ◽  
Ana E. Ledesma ◽  
Elizabeth Imbarack ◽  
Patricio Leyton Bongiorno ◽  
Silvia Antonia Brandán
Keyword(s):  
Dft Calculations ◽  
Spectroscopic Studies ◽  
Visible Spectra ◽  
Ft Ir ◽  
Uv Visible

scholarly journals Field-Induced Single-Ion Magnet Phenomenon in Hexabromo- and Hexaiodorhenate(IV) Complexes

2020 ◽  
Vol 6 (2) ◽  
pp. 20
Author(s):  
Carlos Rojas-Dotti ◽  
Adrián Sanchis-Perucho ◽  
Marta Orts-Arroyo ◽  
Nicolás Moliner ◽  
Ricardo González ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
General Formula ◽  
Crystal Packing ◽  
Variable Temperature ◽  
Magnetic Behaviour ◽  
Octahedral Geometry ◽  
Organic Cations ◽  
Ac Magnetic Susceptibility ◽  
Halide Ions ◽  
Triclinic System

Two mononuclear ReIV complexes of general formula (PPh4)2[ReX6] [PPh4+ = tetraphenylphosphonium cation, X = Br (1) and I (2)] have been prepared and structurally and magnetically characterised. Both compounds crystallise in the triclinic system with space group Pī. Their structures are made up of hexahalorhenate(IV), [ReX6]2−, anions, and bulky PPh4+ cations. Each ReIV ion in 1 and 2 is six-coordinate and bonded to six halide ions in a quasi regular octahedral geometry. In their crystal packing, the [ReX6]2− anions are well separated from each other through the organic cations, generating alternated anionic and cationic layers, and no intermolecular Re−X···X−Re interactions are present. Variable-temperature dc magnetic susceptibility measurements performed on microcrystalline samples of 1 and 2 show a very similar magnetic behaviour, which is typical of noninteracting mononuclear ReIV complexes with S = 3/2. Ac magnetic susceptibility measurements reveal the slow relaxation of the magnetisation in the presence of external dc fields for 1 and 2, hence indicating the occurrence of the field-induced single-ion magnet (SIM) phenomenon in these hexabromo- and hexaiodorhenate(IV) complexes.

scholarly journals Spin State Behavior of A Spin-Crossover Iron(II) Complex with N,N′-Disubstituted 2,6-bis(pyrazol-3-yl)pyridine: A Combined Study by X-ray Diffraction and NMR Spectroscopy

Crystals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 793
Author(s):  
Elizaveta K. Melnikova ◽  
Dmitry Yu. Aleshin ◽  
Igor A. Nikovskiy ◽  
Gleb L. Denisov ◽  
Yulia V. Nelyubina
Keyword(s):  
Nmr Spectroscopy ◽  
Spin State ◽  
Metal Ion ◽  
Spin Crossover ◽  
Molecular Design ◽  
Chemical Shifts ◽  
Variable Temperature ◽  
High Spin State ◽  
X Ray Diffraction ◽  
X Ray

A series of three different solvatomorphs of a new iron(II) complex with N,N′-disubstituted 2,6-bis(pyrazol-3-yl)pyridine, including those with the same lattice solvent, has been identified by X-ray diffraction under the same crystallization conditions with the metal ion trapped in the different spin states. A thermally induced switching between them, however, occurs in a solution, as unambiguously confirmed by the Evans technique and an analysis of paramagnetic chemical shifts, both based on variable-temperature NMR spectroscopy. The observed stabilization of the high-spin state by an electron-donating substituent contributes to the controversial results for the iron(II) complexes of 2,6-bis(pyrazol-3-yl)pyridines, preventing ‘molecular’ design of their spin-crossover activity; the synthesized complex being only the fourth of the spin-crossover (SCO)-active kind with an N,N′-disubstituted ligand.

Sign in / Sign up

Export Citation Format

Share Document