0000000000123214
AUTHOR
Il'ya A. Gural'skiy
Pyridazine-Supported Polymeric Cyanometallates with Spin Transitions
Heterometallic cyano-bridged spin-crossover complexes form a large family of switchable compounds with different structural motives and diverse transition characteristics. Here we report on the hysteretic water-dependent spin transitions found in the family of [Fe(pyridazine)2M(CN)4] frameworks (M = Ni, Pd, Pt). The structure of three new spin-crossover compounds is built of cyanometallic layers supported by pyridazine ligands. The frameworks contain water guest molecules that can be removed upon heating. Spin transition was found in both hydrated and dehydrated compounds, while the removal of water stimulated a complete spin state switch. Mössbauer spectroscopy revealed two different …
Chiral spin crossover nanoparticles and gels with switchable circular dichroism
Spin crossover complexes represent spectacular examples of molecular switchable materials. We describe a new approach towards homochiral coordination nanoparticles of [Fe(NH2trz)3](L-CSA)2 (NH2trz = 4-amino-1,2,4-triazole, L-CSA = L-camphorsulfonate) that display an abrupt switch of chiral properties associated with a cooperative spin transition. This is an original method that generates stable and additive-free colloidal solutions of nanoparticles with a spin transition around room temperature. The introduction of a chiral anion to the coordination framework makes these nanoparticles display specific chiro-optical (circular dichroism) properties that are different in high and low spin stat…
High temperature spin crossover in [Fe(pyrazine){Ag(CN) 2 } 2 ] and its solvate
A high temperature spin crossover (Tup = 367 K) was detected in a metal–organic framework [Fe(pz){Ag(CN)2}2]·MeCN (pz = pyrazine). Upon heating, this solvate released acetonitrile guest molecules, which slightly shifted the transition temperature of the complex (Tup = 370 K and Tdown = 356 K).
Crystal structure of a low-spin poly[di-μ3-cyanido-di-μ2-cyanido-bis(μ2-2-ethylpyrazine)dicopper(I)iron(II)]
In the title metal–organic framework, [Fe(C6H8N2)2{Cu(CN)2}2] n , the low-spin FeII ion lies at an inversion centre and displays an elongated octahedral [FeN6] coordination environment. The axial positions are occupied by two symmetry-related bridging 2-ethylpyrazine ligands, while the equatorial positions are occupied by four N atoms of two pairs of symmetry-related cyanide groups. The CuI centre is coordinated by three cyanide carbon atoms and one N atom of a bridging 2-ethylpyrazine molecule, which form a tetrahedral coordination environment. Two neighbouring Cu atoms have a short Cu...Cu contact [2.4662 (7) Å] and their coordination tetrahedra are connected through a common edge between…
Hofmann-Like Frameworks Fe(2-methylpyrazine)n[M(CN)2]2 (M = Au, Ag) : Spin-Crossover Defined by the Precious Metal
Hofmann-like cyanometalates constitute a large class of spin-crossover iron(II) complexes with variable switching properties. However, it is not yet clearly understood how the temperature and cooperativity of a spin transition are influenced by their structure. In this paper, we report the synthesis and crystal structures of the metal–organic coordination polymers {FeII(Mepz)[AuI(CN)2]2} ([Au]) and {FeII(Mepz)2[AgI(CN)2]2} ([Ag]), where Mepz = 2-methylpyrazine, along with characterization of their spin-state behavior by variable-temperature SQUID magnetometry and Mössbauer spectroscopy. The compounds are built of cyanoheterometallic layers, which are pillared by the bridging Mepz…
Room temperature hysteretic spin crossover in a new cyanoheterometallic framework.
A new iron(II)-based spin-crossover compound with thermal hysteresis operating under ambient conditions is reported. This complex exhibits a high reproducibility of the spin transition in many successive thermal cycles, stability of both spin states at room temperature and an attractive operational temperature range.
Crystal structure of catena-poly[[[(2-ethoxypyrazine-κN)copper(I)]-di-μ2-cyanido] [copper(I)-μ2-cyanido]]
The title compound, {[Cu(EtOpz)(CN)2][CuCN]}n, where EtOpz is 2-ethoxypyrazine, is a two-dimensional polymeric copper complex with different coordination environments of the two CuI ions. One Cu atom is coordinated to the 2-ethoxypyrazine molecule and two bridging cyanide ligands, equally disordered over two sites. The second Cu atom is coordinated by two disordered over two sites bridging cyanide groups. Two copper–cyanide chains are connected through Cu⋯Cu contact.
Pyridinium bis(pyridine-κN)tetrakis(thiocyanato-κN)ferrate(III)
In the title compound, (C5H6N)[Fe(NCS)4(C5H5N)2], the Fe(III) ion is coordinated by four thio-cyanate N atoms and two pyridine N atoms in a trans arrangement, forming an FeN6 polyhedron with a slightly distorted octa-hedral geometry. Charge balance is achieved by one pyridinium cation bound to the complex anion via N-H⋯S hydrogen bonding. The asymmetric unit consists of one Fe(III) cation, four thio-cyanate anions, two coordinated pyridine mol-ecules and one pyridinium cation. The structure exhibits π-π inter-actions between pyridine rings [centroid-centroid distances = 3.7267 (2), 3.7811 (2) and 3.8924 (2) Å]. The N atom and a neighboring C atom of the pyridinium cation are statistically d…
Iron (II) isothiocyanate complexes with substituted pyrazines: Experimental and theoretical views on their electronic structure
Abstract Synthesis, structural, magnetic, Mossbauer and thermal studies of isothiocyanate iron (II) complexes with substituted pyrazines (iodo-, bromo- and amino-derivatives) are discussed here. Complexes with iodo- and bromo-derivatives were found to have the composition [Fe(Ipz)2(SCN)2(H2O)2]·2Ipz (1) and [Fe(Brpz)2(SCN)2(H2O)2]·2Brpz (2), whereas in the case of amino-functionalized pyrazine the formation of [Fe(NH2pz)4(SCN)2] (3) was observed. 3D organization of the molecular complexes is stabilized within different hydrogen, halogen and lone pair–π interactions. Spin state of iron (II) ions in 1–3 was determined as high spin by Mossbauer and magnetic measurements. DFT calculations for t…
Pyridinium bis(pyridine-κN)tetrakis(thiocyanato-κN)ferrate(III)
In the title compound, (C5H6N)[Fe(NCS)4(C5H5N)2], the FeIII ion is coordinated by four thiocyanate N atoms and two pyridine N atoms in a trans arrangement, forming an FeN6 polyhedron with a slightly distorted octahedral geometry. Charge balance is achieved by one pyridinium cation bound to the complex anion via N—H...S hydrogen bonding. The asymmetric unit consists of one FeIII cation, four thiocyanate anions, two coordinated pyridine molecules and one pyridinium cation. The structure exhibits π–π interactions between pyridine rings [centroid–centroid distances = 3.7267 (2), 3.7811 (2) and 3.8924 (2) Å]. The N atom and a neighboring C…
Cooperative High-Temperature Spin Crossover Accompanied by a Highly Anisotropic Structural Distortion
Spin transitions are a spectacular example of molecular switching that can provoke extreme electronic and structural reorganizations in coordination compounds. A new 3D cyanoheterometallic framework, [Fe(pz)(Au(CN)2)2], has been synthesized in which a highly cooperative spin crossover has been observed at 367 and 349 K in heating and cooling modes, respectively. Mössbauer spectroscopy revealed a complete transition between the diamagnetic and paramagnetic states of the iron centres. The low-spin-to-high-spin transition induced a drastic structural distortion involving a large one-directional expansion (ca. 10.6%) and contraction (ca. 9.6%) of the lattice. Negative thermal expansion along th…
Enantioselective Guest Effect on the Spin State of a Chiral Coordination Framework
The diversity of spin crossover (SCO) complexes that, on the one hand, display variable temperature, abruptness and hysteresis of the spin transition, and on the other hand, are spin-sensitive to the various guest molecules, makes these materials unique for the detection of different organic and inorganic compounds. We have developed a homochiral SCO coordination polymer with a spin transition sensitive to the inclusion of the guest 2-butanol, and these solvates with (R)- and (S)-alcohols demonstrate different SCO behaviours depending on the chirality of the organic analyte. A stereoselective response to the guest inclusion is detected as a shift in the temperature of the transition both fr…
Pyridinium bis(pyridine-κN)tetrakis(thiocyanato-κN)ferrate(III) -pyrazine-2-carbonitrile-pyridine (1/4/1)
In the title compound, (C5H6N)[Fe(NCS)4(C5H5N)2]·4C5H3N3·C5H5N, the Fe(III) ion is located on an inversion centre and is six-coordinated by four N atoms of the thio-cyanate ligands and two pyridine N atoms in a trans arrangement, forming a slightly distorted octa-hedral geometry. A half-occupied H atom attached to a pyridinium cation forms an N-H⋯N hydrogen bond with a centrosymmetrically-related pyridine unit. Four pyrazine-2-carbo-nitrile mol-ecules crystallize per complex anion. In the crystal, π-π stacking inter-actions are present [centroid-centroid distances = 3.6220 (9), 3.6930 (9), 3.5532 (9), 3.5803 (9) and 3.5458 (8) Å].
Co–Co and Co–Fe cyano-bridged pentanuclear clusters based on a methylpyrazinyl-diamine tetradentate ligand: spin crossover and metal substitution effects
A pentanuclear [CoII3CoIII2] cluster complex has been developed by a solvothermal synthesis. Its highly stable metal-mixed Fe–Co derivatives display robust spin crossover (T1/2 = 268 K) controlled by the degree of substitution.
Spin-State-Dependent Redox-Catalytic Activity of a Switchable Iron(II) Complex
The spin state of catalytically active 3d metal centers plays a significant role for their activity in enzymatic processes and organometallic catalysis. Here we report on the catalytic activity of a Fe(II) coordination compound that can undergo a cooperative switch between low-spin (LS) and high-spin (HS) states. Catalytic measurements within 291 - 318 K temperature region reveal a drastic drop of the catalytic activity upon conversion of metallic centers from the LS to the HS form. For a thermoswitchable [Fe(NH2trz)3]Br2 complex (Tup = 305 K), an activation energy is found to be considerably lower for the LS state (158 kJ mol-1) comparing to the HS state (305 kJ mol-1). Mossbauer analysis …
Spin Crossover in Fe(II)–M(II) Cyanoheterobimetallic Frameworks (M = Ni, Pd, Pt) with 2-Substituted Pyrazines
Discovery of spin-crossover (SCO) behavior in the family of Fe(II)-based Hofmann clathrates has led to a "new rush" in the field of bistable molecular materials. To date this class of SCO complexes is represented by several dozens of individual compounds, and areas of their potential application steadily increase. Starting from Fe(2+), square planar tetracyanometalates M(II)(CN)4(2-) (M(II) = Ni, Pd, Pt) and 2-substituted pyrazines Xpz (X = Cl, Me, I) as coligands we obtained a series of nine new Hofmann clathrate-like coordination frameworks. X-ray diffraction reveals that in these complexes Fe(II) ion has a pseudo-octahedral coordination environment supported by four μ4-tetracyanometallat…
Multiple spin phases in a switchable Fe(ii) complex: polymorphism and symmetry breaking effects
Polymorphism in spin-crossover (SCO) compounds allows accessing additional forms of switchable materials with diverse transition properties. We have prepared three polymorphs of a new complex [FeLBr(dca)2], where LBr is N,N′-bis[(5-bromo-2-pyridyl)methyl]ethane-1,2-diamine and dca is dicyanamide. They display different SCO properties: the α-form displays a hysteretic one-step switch centered at 134 K, the β-form undergoes hysteretic two-step spin transition with a plateau (T1/2 = 153 and 144 K) and the γ-form remains high spin (HS) over the whole temperature region. The kinetic origin of the hysteresis loop was demonstrated in temperature rate dependent magnetic measurements. Spin transitio…
Haloperoxidase Mimicry by CeO2−xNanorods Combats Biofouling
CeO2-x nanorods are functional mimics of natural haloperoxidases. They catalyze the oxidative bromination of phenol red to bromophenol blue and of natural signaling molecules involved in bacterial quorum sensing. Laboratory and field tests with paint formulations containing 2 wt% of CeO2-x nanorods show a reduction in biofouling comparable to Cu2 O, the most typical biocidal pigment.
CCDC 1422402: Experimental Crystal Structure Determination
Related Article: Il'ya A. Gural'skiy, Bohdan O. Golub, Sergii I. Shylin, Vadim Ksenofontov, Helena J. Shepherd, Paul R. Raithby, Wolfgang Tremel and Igor O. Fritsky|2016|Eur.J.Inorg.Chem.||3191|doi:10.1002/ejic.201600406
CCDC 1422398: Experimental Crystal Structure Determination
Related Article: Il'ya A. Gural'skiy, Bohdan O. Golub, Sergii I. Shylin, Vadim Ksenofontov, Helena J. Shepherd, Paul R. Raithby, Wolfgang Tremel and Igor O. Fritsky|2016|Eur.J.Inorg.Chem.||3191|doi:10.1002/ejic.201600406
CCDC 1422396: Experimental Crystal Structure Determination
Related Article: Il'ya A. Gural'skiy, Bohdan O. Golub, Sergii I. Shylin, Vadim Ksenofontov, Helena J. Shepherd, Paul R. Raithby, Wolfgang Tremel and Igor O. Fritsky|2016|Eur.J.Inorg.Chem.||3191|doi:10.1002/ejic.201600406
CCDC 1422397: Experimental Crystal Structure Determination
Related Article: Il'ya A. Gural'skiy, Bohdan O. Golub, Sergii I. Shylin, Vadim Ksenofontov, Helena J. Shepherd, Paul R. Raithby, Wolfgang Tremel and Igor O. Fritsky|2016|Eur.J.Inorg.Chem.||3191|doi:10.1002/ejic.201600406
CCDC 1838583: Experimental Crystal Structure Determination
Related Article: Il'ya A. Gural'skiy, Sergii I. Shylin, Vadim Ksenofontov, and Wolfgang Tremel|2019|Eur.J.Inorg.Chem.|2019|4532|doi:10.1002/ejic.201900782
CCDC 1422405: Experimental Crystal Structure Determination
Related Article: Il'ya A. Gural'skiy, Bohdan O. Golub, Sergii I. Shylin, Vadim Ksenofontov, Helena J. Shepherd, Paul R. Raithby, Wolfgang Tremel and Igor O. Fritsky|2016|Eur.J.Inorg.Chem.||3191|doi:10.1002/ejic.201600406
CCDC 1422399: Experimental Crystal Structure Determination
Related Article: Il'ya A. Gural'skiy, Bohdan O. Golub, Sergii I. Shylin, Vadim Ksenofontov, Helena J. Shepherd, Paul R. Raithby, Wolfgang Tremel and Igor O. Fritsky|2016|Eur.J.Inorg.Chem.||3191|doi:10.1002/ejic.201600406
CCDC 1569643: Experimental Crystal Structure Determination
Related Article: Bin Fei, Jian Zhou, Zheng Yan, Sergii I. Shylin, Vadim Ksenofontov, Il'ya A. Gural'skiy, Xin Bao|2017|CrystEngComm|19|7079|doi:10.1039/C7CE01826F
CCDC 1422403: Experimental Crystal Structure Determination
Related Article: Il'ya A. Gural'skiy, Bohdan O. Golub, Sergii I. Shylin, Vadim Ksenofontov, Helena J. Shepherd, Paul R. Raithby, Wolfgang Tremel and Igor O. Fritsky|2016|Eur.J.Inorg.Chem.||3191|doi:10.1002/ejic.201600406
CCDC 1838587: Experimental Crystal Structure Determination
Related Article: Il'ya A. Gural'skiy, Sergii I. Shylin, Vadim Ksenofontov, and Wolfgang Tremel|2019|Eur.J.Inorg.Chem.|2019|4532|doi:10.1002/ejic.201900782
CCDC 1478973: Experimental Crystal Structure Determination
Related Article: Il'ya A. Gural'skiy, Sergii I. Shylin, Bohdan O. Golub, Vadim Ksenofontov, Igor O. Fritsky, Wolfgang Tremel|2016|New J.Chem.|40|9012|doi:10.1039/C6NJ01472K
CCDC 1838584: Experimental Crystal Structure Determination
Related Article: Il'ya A. Gural'skiy, Sergii I. Shylin, Vadim Ksenofontov, and Wolfgang Tremel|2019|Eur.J.Inorg.Chem.|2019|4532|doi:10.1002/ejic.201900782
CCDC 1569642: Experimental Crystal Structure Determination
Related Article: Bin Fei, Jian Zhou, Zheng Yan, Sergii I. Shylin, Vadim Ksenofontov, Il'ya A. Gural'skiy, Xin Bao|2017|CrystEngComm|19|7079|doi:10.1039/C7CE01826F
CCDC 1838585: Experimental Crystal Structure Determination
Related Article: Il'ya A. Gural'skiy, Sergii I. Shylin, Vadim Ksenofontov, and Wolfgang Tremel|2019|Eur.J.Inorg.Chem.|2019|4532|doi:10.1002/ejic.201900782
CCDC 1878182: Experimental Crystal Structure Determination
Related Article: Volodymyr M. Hiiuk, Sergiu Shova, Aurelian Rotaru, Vadim Ksenofontov, Igor O. Fritsky, Il'ya A. Gural'skiy|2019|Chem.Commun.|55|3359|doi:10.1039/C8CC10260K
CCDC 1838588: Experimental Crystal Structure Determination
Related Article: Il'ya A. Gural'skiy, Sergii I. Shylin, Vadim Ksenofontov, and Wolfgang Tremel|2019|Eur.J.Inorg.Chem.|2019|4532|doi:10.1002/ejic.201900782
CCDC 1422404: Experimental Crystal Structure Determination
Related Article: Il'ya A. Gural'skiy, Bohdan O. Golub, Sergii I. Shylin, Vadim Ksenofontov, Helena J. Shepherd, Paul R. Raithby, Wolfgang Tremel and Igor O. Fritsky|2016|Eur.J.Inorg.Chem.||3191|doi:10.1002/ejic.201600406
CCDC 1838586: Experimental Crystal Structure Determination
Related Article: Il'ya A. Gural'skiy, Sergii I. Shylin, Vadim Ksenofontov, and Wolfgang Tremel|2019|Eur.J.Inorg.Chem.|2019|4532|doi:10.1002/ejic.201900782
CCDC 1422400: Experimental Crystal Structure Determination
Related Article: Il'ya A. Gural'skiy, Bohdan O. Golub, Sergii I. Shylin, Vadim Ksenofontov, Helena J. Shepherd, Paul R. Raithby, Wolfgang Tremel and Igor O. Fritsky|2016|Eur.J.Inorg.Chem.||3191|doi:10.1002/ejic.201600406
CCDC 1569644: Experimental Crystal Structure Determination
Related Article: Bin Fei, Jian Zhou, Zheng Yan, Sergii I. Shylin, Vadim Ksenofontov, Il'ya A. Gural'skiy, Xin Bao|2017|CrystEngComm|19|7079|doi:10.1039/C7CE01826F
CCDC 1878181: Experimental Crystal Structure Determination
Related Article: Volodymyr M. Hiiuk, Sergiu Shova, Aurelian Rotaru, Vadim Ksenofontov, Igor O. Fritsky, Il'ya A. Gural'skiy|2019|Chem.Commun.|55|3359|doi:10.1039/C8CC10260K
CCDC 1422401: Experimental Crystal Structure Determination
Related Article: Il'ya A. Gural'skiy, Bohdan O. Golub, Sergii I. Shylin, Vadim Ksenofontov, Helena J. Shepherd, Paul R. Raithby, Wolfgang Tremel and Igor O. Fritsky|2016|Eur.J.Inorg.Chem.||3191|doi:10.1002/ejic.201600406