scholarly journals New Spin-Crossover Compounds Containing the [Ni(mnt)] Anion (mnt = Maleonitriledithiolate)

2021 ◽  
Vol 7 (5) ◽  
pp. 72
Author(s):  
Scott S. Turner ◽  
Joanna Daniell ◽  
Hiroki Akutsu ◽  
Peter N. Horton ◽  
Simon J. Coles ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Single Crystal ◽  
Spin Crossover ◽  
Variable Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Counter Ions ◽  
Bulk Magnetization ◽  
L1 And L2 ◽  
Derivatives Of

Two novel salts containing the anion [Ni(mnt)2]− (mnt = maleonitriledithiolate) have been synthesized. The counter-ions, [Fe(II)(L1 or L2)2], are cationic complexes where L1 and L2 are methylated derivatives of 2,6-bis(pyazolyl)pyridine or pyrazine, which are similar to ligands found in a series of spin-crossover (SCO) complexes. Both salts are characterized by variable temperature single crystal X-ray diffraction and bulk magnetization measurements. Compound 1, [Fe(II)(L1)2][Ni(mnt)2]2 displays an incomplete and gradual SCO up to 300 K, followed by a more rapid increase in the high-spin fraction between 300 and 350 K. Compound 2, [Fe(II)(L2)2][Ni(mnt)2]2.MeNO2, shows a gradual, but more complete SCO response centered at 250 K. For compound 2, the SCO is confirmed by variable temperature Mössbauer spectroscopy. In both cases, the anionic moieties are isolated from each other and so no electrical conductivity is observed.

Trigold(I) Phosphine Derivatives of Clusters Containing Octahedral Rh2Ru4B-Boride Cores: The X-Ray Structure of [Rh2Ru4(CO)15Rh2Ru4B{AuPCy3}3] (Cy = cyclohexyl)

1999 ◽  
Vol 64 (6) ◽  
pp. 959-970 ◽  
Author(s):  
Andrew D. Hattersley ◽  
Catherine E. Housecroft ◽  
Arnold L. Rheingold
Keyword(s):  
Nmr Spectroscopy ◽  
Single Crystal ◽  
Boron Atom ◽  
Variable Temperature ◽  
Mass Spectrometric ◽  
X Ray Diffraction ◽  
X Ray ◽  
The Third ◽  
Phosphine Derivatives ◽  
Derivatives Of

The reaction of [Rh(CO)2Cl]2 with [HRu4(CO)12BH]- followed by treatment with an excess (at least three-fold) of [Cy3PAuCl] (Cy = cyclohexyl) leads to the formation of [Rh2Ru4(CO)16B{AuPCy3}] (previously prepared by another route) and [Rh2Ru4(CO)15B{AuPCy3}3]. The new trigold derivative has been characterized by spectroscopic and mass spectrometric methods, and by single crystal X-ray diffraction. It possesses an octahedral Rh2Ru4 core containing an interstitial boron atom; two of the gold(I) phosphine units cap two adjacent faces and the third bridges an edge of the octahedral cage. There are no close Au···Au contacts. Reactions of [Rh2Ru4(CO)16B]- with [(R3PAu)3O]+ (R = Ph, 2-MeC6H4) resulted in the formation of [Rh2Ru4(CO)15B{AuPR3}3]; for R = Ph, two isomers in respect of the arrangements of the AuPPh3 were isolated. Fluxional processes involving the gold(I) phosphine fragments have been observed using solution variable-temperature 31P NMR spectroscopy.

scholarly journals Spin Crossover in Bipyridine Derivative Bridged One-Dimensional Iron(III) Coordination Polymer

2020 ◽  
Vol 6 (3) ◽  
pp. 29
Author(s):  
Ryuta Ishikawa ◽  
Takeshi Noda ◽  
Shunya Ueno ◽  
Takashi Okubo ◽  
Hirofumi Yamakawa ◽  
...  
Keyword(s):  
Single Crystal ◽  
Spin Crossover ◽  
Continuous Wave ◽  
Variable Temperature ◽  
Molecular Structures ◽  
X Ray Diffraction ◽  
Paramagnetic Resonance ◽  
One Dimensional ◽  
X Ray ◽  
Susceptibility Data

Herein, the syntheses, solid-state molecular structures, and characterization of two types of one-dimensional FeIII coordination polymers showing thermally induced spin crossover are reported. The reaction of [Fe(acen)Cl] (acen2− = N,N′-ethylenebis(acetylacetonylideneaminate) with 3,3′-bpy or 4,4′-bpy (bpy = bipyridine) produced zigzag and linear one-dimensional chain complexes, [Fe(acen)(3,3′-bpy)][BPh4] (1) or [NEt3H][Fe(acen)(4,4′-bpy)][BPh4]2·0.5(4,4′-bpy) (2), respectively, as confirmed by single crystal X-ray diffraction analysis. Variable-temperature single crystal X-ray diffraction measurements, continuous-wave X-band electron paramagnetic resonance (EPR) spectra, 57Fe Mössßauer spectra, and DC magnetic susceptibility data revealed that complex 1 exhibited a gradual and complete spin crossover at a transition temperature of 212 K, while complex 2 undergoes an incomplete spin crossover even at 400 K.

Molecular motions of a tetraphenylethylene-derived AIEgen directly monitored through in situ variable temperature single crystal X-ray diffraction

CrystEngComm ◽  
2021 ◽  
Author(s):  
Wei Meng ◽  
Lin Du ◽  
Lin Sun ◽  
Lian Zhou ◽  
Xiaopeng Xuan ◽  
...  
Keyword(s):  
Single Crystal ◽  
Phenyl Ring ◽  
Functional Group ◽  
Variable Temperature ◽  
Molecular Motions ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
X Ray ◽  
Conformation Changes

One organic functional group was introduced to distinguish the four phenyl ring of tetraphenylethylene, and the In situ temperature-dependent crystal structures were determined to exhibit the conformation changes of tert-butyl...

The structures and phase transitions in 4-aminopyridinium tetraaquabis(sulfato)iron(III), (C5H7N2)[FeIII(H2O)4(SO4)2]

2019 ◽  
Vol 75 (6) ◽  
pp. 1144-1151
Author(s):  
Tamara J. Bednarchuk ◽  
Wolfgang Hornfeck ◽  
Vasyl Kinzhybalo ◽  
Zhengyang Zhou ◽  
Michal Dušek ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Single Crystal ◽  
Room Temperature ◽  
Variable Temperature ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Hybrid Compound ◽  
Space Group ◽  
X Ray

The organic–inorganic hybrid compound 4-aminopyridinium tetraaquabis(sulfato)iron(III), (C5H7N2)[FeIII(H2O)4(SO4)2] (4apFeS), was obtained by slow evaporation of the solvent at room temperature and characterized by single-crystal X-ray diffraction in the temperature range from 290 to 80 K. Differential scanning calorimetry revealed that the title compound undergoes a sequence of three reversible phase transitions, which has been verified by variable-temperature X-ray diffraction analysis during cooling–heating cycles over the temperature ranges 290–100–290 K. In the room-temperature phase (I), space group C2/c, oxygen atoms from the closest Fe-atom environment (octahedral) were disordered over two equivalent positions around a twofold axis. Two intermediate phases (II), (III) were solved and refined as incommensurately modulated structures, employing the superspace formalism applied to single-crystal X-ray diffraction data. Both structures can be described in the (3+1)-dimensional monoclinic X2/c(α,0,γ)0s superspace group (where X is ½, ½, 0, ½) with modulation wavevectors q = (0.2943, 0, 0.5640) and q = (0.3366, 0, 0.5544) for phases (II) and (III), respectively. The completely ordered low-temperature phase (IV) was refined with the twinning model in the triclinic P{\overline 1} space group, revealing the existence of two domains. The dynamics of the disordered anionic substructure in the 4apFeS crystal seems to play an essential role in the phase transition mechanisms. The discrete organic moieties were found to be fully ordered even at room temperature.

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.

scholarly journals High-temperature in situ crystallographic observation of reversible gas sorption in impermeable organic cages

2015 ◽  
Vol 112 (46) ◽  
pp. 14156-14161 ◽  
Author(s):  
Seung Bin Baek ◽  
Dohyun Moon ◽  
Robert Graf ◽  
Woo Jong Cho ◽  
Sung Woo Park ◽  
...  
Keyword(s):  
Single Crystal ◽  
High Temperatures ◽  
Direct Detection ◽  
Variable Temperature ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dynamic Motion

Crystallographic observation of adsorbed gas molecules is a highly difficult task due to their rapid motion. Here, we report the in situ single-crystal and synchrotron powder X-ray observations of reversible CO2 sorption processes in an apparently nonporous organic crystal under varying pressures at high temperatures. The host material is formed by hydrogen bond network between 1,3,5-tris-(4-carboxyphenyl)benzene (H3BTB) and N,N-dimethylformamide (DMF) and by π–π stacking between the H3BTB moieties. The material can be viewed as a well-ordered array of cages, which are tight packed with each other so that the cages are inaccessible from outside. Thus, the host is practically nonporous. Despite the absence of permanent pathways connecting the empty cages, they are permeable to CO2 at high temperatures due to thermally activated molecular gating, and the weakly confined CO2 molecules in the cages allow direct detection by in situ single-crystal X-ray diffraction at 323 K. Variable-temperature in situ synchrotron powder X-ray diffraction studies also show that the CO2 sorption is reversible and driven by temperature increase. Solid-state magic angle spinning NMR defines the interactions of CO2 with the organic framework and dynamic motion of CO2 in cages. The reversible sorption is attributed to the dynamic motion of the DMF molecules combined with the axial motions/angular fluctuations of CO2 (a series of transient opening/closing of compartments enabling CO2 molecule passage), as revealed from NMR and simulations. This temperature-driven transient molecular gating can store gaseous molecules in ordered arrays toward unique collective properties and release them for ready use.

scholarly journals A combined single crystal neutron/X-ray diffraction and solid-state nuclear magnetic resonance study of the hybrid perovskites CH3NH3PbX3 (X = I, Br and Cl)

2015 ◽  
Vol 3 (17) ◽  
pp. 9298-9307 ◽  
Author(s):  
Tom Baikie ◽  
Nathan S. Barrow ◽  
Yanan Fang ◽  
Philip J. Keenan ◽  
Peter R. Slater ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Solid State ◽  
Single Crystal ◽  
Solid State Nmr ◽  
Variable Temperature ◽  
Neutron Diffraction Study ◽  
Nuclear Magnetic Resonance Study ◽  
X Ray Diffraction ◽  
Magnetic Resonance Study ◽  
X Ray

This article describes a variable temperature solid-state NMR and single crystal X-ray/neutron diffraction study of the hybrid perovskites (CH3NH3)PbX3 (X = I, Br and Cl).

Sign in / Sign up

Export Citation Format

Share Document