Thermoanalytical study of linkage isomerism in coordination compounds. Part III: A DSC study on the effect of counterion on the solid state isomerization of nitro and nitrito linkage isomers of pentaamminecobalt(III) complexes

2014 ◽  
Vol 575 ◽  
pp. 114-121 ◽  
Author(s):  
Abbas Eslami ◽  
Nahid Hasani
Keyword(s):  
Solid State ◽  
Coordination Compounds ◽  
Thermoanalytical Study ◽  
Linkage Isomers ◽  
Linkage Isomerism

scholarly journals Photocrystallographic and kinetic studies of metastable linkage isomers

2014 ◽  
Vol 70 (a1) ◽  
pp. C773-C773
Author(s):  
Lauren Hatcher ◽  
Paul Raithby
Keyword(s):  
Steady State ◽  
Solid State ◽  
Rational Design ◽  
Molecular System ◽  
Kinetic Studies ◽  
Research Area ◽  
Linkage Isomers ◽  
Linkage Isomerism ◽  
State Kinetic ◽  
Selection Of

The ability of a molecular system to reversibly convert between two distinct states on photoactivation is desirable for many real-world applications, including photo-switchable device media. When induced in the solid-state, the process can be studied by crystallography and specifically photocrystallographic methods have contributed greatly to this diverse research area. The process of linkage isomerism has proved popular for photocrystallographic study. While the atomic rearrangements involved in the process are large enough to be determined from diffraction data, the changes are also moderate enough that crystal integrity is often maintained. Examples of species studied by these methods include nitrite, sulfur dioxide and nitrosyl coordination complexes [1]. Our research has focused on metal–nitrite complexes displaying nitro–nitrito isomerism and has aimed toward the rational design of new systems to undergo maximum conversion. Recently we have studied a selection of nickel–amine systems, including [Ni(Et4dien)(η2-O,ON)(η1-NO2)]. This complex shows diverse linkage isomeric behaviour on thermal and photochemical treatment [2], with 100% nitro–nitrito conversion achieved on excitation at λ = 500nm. The thermal and photochemical processes have been studied in detail [3] and the results of temperature studies, steady-state and pseudo-steady-state photocrystallographic experiments and solid-state kinetic studies are presented. The findings are discussed in relation to the key information they provide on the steric and kinetic factors that may influence the isomerisation process in the single-crystal.

Formation of di- and polynuclear Mn(II) thiocyanate pyrazole complexes in solution and in the solid state

2018 ◽  
Vol 73 (11) ◽  
pp. 793-801
Author(s):  
Aleksej Jochim ◽  
Christian Näther
Keyword(s):  
Solid State ◽  
Coordination Compounds ◽  
Magnetic Measurements ◽  
Metal Cations ◽  
Chain Compound ◽  
Pyrazole Ligands

AbstractReaction of Mn(NCS)2with pyrazole leads to the formation of three compounds with the compositions Mn(NCS)2(pyrazole)4(1), [Mn(NCS)2]2(pyrazole)6(2) and Mn(NCS)2(pyrazole)2(3). Compound1, already reported in the literature, consists of discrete complexes, in which the Mn(II) cations are octahedrally coordinated by four pyrazole ligands and two terminally N-bonded thiocyanate anions. In compound2each of the two Mn(II) cations are coordinated octahedrally by three pyrazole ligands and one terminal as well as two bridging thiocyanate anions, which link the metal cations into dimers. In compound3also octahedrally coordinated Mn(II) cations are present but they are linked into chainsviacentrosymmetric pairs ofμ-1,3-bridging thiocyanate anions. Upon heating compound1loses the pyrazole co-ligands stepwise and is transformed into the chain compound3viathe dimer2that is formed as an intermediate. Magnetic measurements on compounds2and3reveal dominating antiferromagnetic interactions, as already observed for 1D Mn(NCS)2coordination compounds with pyridine based co-ligands.

The decomposition mechanism of new solid-state 4(5)-aminoimidazole-5(4)-carboxamide coordination compounds

2004 ◽  
Vol 409 (2) ◽  
pp. 145-150 ◽  
Author(s):  
S. Materazzi ◽  
S. Aquili ◽  
C. Bianchetti ◽  
G. D’Ascenzo ◽  
K.M. Kadish ◽  
...  
Keyword(s):  
Solid State ◽  
Coordination Compounds ◽  
Decomposition Mechanism

Coordination compounds of substituted 1,10-Phenanthrolines and related dipyridyls. VII. Complexes of copper(I) and 4,6,4',6'-Tetramethyl-2,2'-bipyridine

1965 ◽  
Vol 18 (9) ◽  
pp. 1339 ◽  
Author(s):  
JR Hall ◽  
MR Litzow ◽  
RA Plowman
Keyword(s):  
Solid State ◽  
Physical Properties ◽  
Copper Atom ◽  
Coordination Compounds ◽  
Donor Nitrogen ◽  
Partial Dissociation

A number of diamagnetic complexes of copper(I) and 4,6,4',6'-tetramethyl-2,2'-bipyridine (tmb) have been prepared and some physical properties measured. The complexes of formula Cu(tmb)2X where X = NO3, ClO4, Br, and I behave as 1 : 1 electrolytes in nitrobenzene and nitromethane, while the complex Cu(tmb)2Cl,H2O apparently undergoes partial dissociation in these solvents. All are expected to have a tetrahedral arrangement of the four donor nitrogen atoms about the copper atom. The mono complexes CuXtmb, where X = Cl, Br, and I, appear to be dimeric in the solid state with halogen bridging, but in solution the chloro and bromo complexes rearrange to varying degrees depending on the solvent, forming the salt-type compounds [Cu(tmb)2][CuX2]. CuItmb is insoluble in all common solvents.

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