Low-Dimensional 3d–4f Complexes Assembled by Low-Spin [FeIII(phen)(CN)4]− Anions

The synthesis, crystal structure, and magnetic properties of four new mixed 3d-4f complexes with formulas [{FeIII(phen)(CN)4} 4Gd2 III(bpym)(NO3) 2(H2O)4]·2CH3CN· 2H2O}n (1), [{FeIII(phen)(CN)4} 4Tb2 III(bpym)(H2O) 8]·(NO3)2·2CH3CN} n (2), [{FeIII(phen)(CN)4}4Sm III(bpym)(NO3)2(H2O) 5]·2CH3CN}n (3), and [{Fe III(phen)(CN)4}2Pr2 III(bpym)(NO3)4(H2O) 2]n (4) (phen = 1,10-phenanthroline and bpym = 2,2′-bipyrimidine) are discussed here. Compounds 1-3 are isomorphous and their structure consists of neutral ladder-like motifs where the rungs are made up by bpym-bridged dilanthanide(III) cations and the rods are defined by [Fe(phen)(CN)4]- units adopting a bis-monodentate coordination mode through…

Prussian Blue Analogues of Reduced Dimensionality

Abstract: Mixed-valence polycyanides (Prussian Blue analogues) possess a rich palette of properties spanning from room-temperature ferromagnetism to zero thermal expansion, which can be tuned by chemical modifications or the application of external stimuli (temperature, pressure, light irradiation). While molecule-based materials can combine physical and chemical properties associated with molecular-scale building blocks, their successful integration into real devices depends primarily on higher-order properties such as crystal size, shape, morphology, and organization. Herein a study of a new reduced-dimensionality system based on Prussian Blue analogues (PBAs) is presented. The system is …

[Fe(III)(dmbpy)(CN)4]-: a new building block for designing single-chain magnets.

We herein present the synthesis and magneto-structural study of a new family of heterobimetallic chains of general formula {[Fe(III)(dmbpy)(CN)(4)](2)M(II)(H(2)O)(2)}(n)·pnH(2)O [dmbpy = 4,4'-dimethyl-2,2'-bipyridine; M = Mn (2), Cu (3), Ni (4) and Co (5) with p = 4 (2), 3 (3), 9 (4) and 3.5 (5)] which were prepared by using the mononuclear PPh(4)[Fe(III)(dmbpy)(CN)(4)]·3H(2)O (1) building block (PPh(4)(+) = tetraphenylphosphonium) as a ligand toward fully solvated M(II) ions. The structure of 1 consists of discrete [Fe(III)(dmbpy)(CN)(4)](-) anions, tetraphenylphosphonium cations and noncoordinated water molecules. Complexes 2-5 are isostructural compounds whose structure consists of neutr…

Slow relaxation of the magnetization in a 4,2-wavelike Fe(III)2Co(II) heterobimetallic chain.

The reaction of the low-spin iron(III) complex [Fe(dmbpy)(CN)(4)](-) (1) with fully solvated cobalt(II) ions affords the cyanide-bridged heterobimetallic chain {[Fe(III)(dmbpy)(CN)(4)](2)Co(II)(H(2)O)(2)}(n) · 4nH(2)O (2), which exhibits intrachain ferromagnetic coupling and double slow relaxation of the magnetization.

Nuclearity controlled cyanide-bridged bimetallic CrIII-MnII compounds: synthesis, crystal structures, magnetic properties and theoretical calculations.

The preparation, X-ray crystallography and magnetic investigation of the compounds PPh4[Cr(bipy)(CN)4].2 CH3CN.H2O (1) (mononuclear), [[Cr(bipy)(CN)4]2Mn-(H2O)4].4H2O (2) (trinuclear), [[Cr(bipy)(CN)4]2Mn(H2O)2] (3) (chain) and [[Cr(bipy)(CN)4]2Mn(H2O)].H2O.CH3CN (4) (double chain) [bipy=2,2'-bipyridine; PPh4 (+)=tetraphenylphosphonium] are described herein. The [Cr(bipy)(CN)4]- unit act either as a monodentate (2) or bis-monodentate (3) ligand toward the manganese atom through one (2) or two (3) of its four cyanide groups. The manganese atom is six-coordinate with two (2) or four (3) cyanide nitrogens and four (2) or two (3) water molecules building a distorted octahedral environment. In 4…

Synthesis, crystal structures and magnetic properties of single and double cyanide-bridged bimetallic Fe2(III)Cu(II) zigzag chains.

The bimetallic complexes [[Fe(III)(phen)(CN)4]2Cu(II)(H2O)2].4H2O (1), [[Fe(III)(phen)(CN)4]2Cu(II)].H2O (2) and [[Fe(III)(bipy)(CN)4]2Cu(II)].2H2O (3) and [[Fe(III)(bipy)(CN)4]2Cu(II)(H2O)2].4H2O (4) (phen = 1,10-phenanthroline and bipy = 2,2'-bipyridine) have been prepared and the structures of 1-3 determined by X-ray diffraction. The structure of 1 is made up of neutral cyanide-bridged Fe(III)-Cu(II) zigzag chains of formula [[Fe(III)(phen)(CN)4]2Cu(II)(H2O)2] and uncoordinated water molecules with the [Fe(phen)(CN)4]- entity acting as a bis-monodentate bridging ligand toward two trans-diaquacopper(II) units through two of its four cyanide groups in cis positions. The structure of 2 can …

Mixed Valence Materials: Prussian Blue Analogues of Reduced Dimensionality (Small 16/2012)

Trans-dicyanobis(acetylacetonato)ruthenate(III) as a precursor to build novel cyanide-bridged RuIII–MII bimetallic compounds [M=Co and Ni]

Abstract The use of the mononuclear complex trans-[Ru(acac)2(CN)2]− as a ligand towards the preformed species [Ni2L(H2O)2Cl2], [Co(dmphen)](NO3)2, [Ni(dmphen)](NO3)2 and [Co(H2O)6](NO3)2 afforded the novel cyanide-bridged bimetallic compounds of formula [{Ru(acac)2(CN)2}{Ni2(L)(H2O)2}]{Ru(acac)2(CN)2}·2H2O (1), [{Ru(acac)2(CN)2}{Co(dmphen)(NO3)}]·H2O (2) and [{Ru(acac)2(CN)2}{Ni(dmphen)(NO3)}]·H2O (3) and [{Ru(acac)2(CN)2}2Co] (4) [Hacac = acetylacetone, dmphen = 2,9-dimethylphenanthroline and H2L = 11,23-dimethyl-3,7,15,19-tetrazatricyclo[19.3.1.19,13]hexacosa-2,7,9,11,13(26),14,19,21(25),22,24-decaene-25,26-diol]. Their syntheses, X-ray crystal structures and magnetic properties are repor…

The influence of pseudohalide ligands on the SIM behaviour of four-coordinate benzylimidazole-containing cobalt(ii) complexes.

Three, mononuclear complexes of the formula [Co(bmim)2(SCN)2] (1), [Co(bmim)2(NCO)2] (2) and [Co(bmim)2(N3)2] (3) [bmim = 1-benzyl-2-methylimidazole] were prepared and structurally analyzed by single-crystal X-ray crystallography. The cobalt(ii) ions in 1-3 are tetrahedrally coordinated with two bmim molecules and two pseudohalide anions. The angular distortion parameter δ was calculated and the SHAPE program (based on the CShM concept) was used for 1-3 to estimate the angular distortion from an ideal tetrahedron. The molecules of 1-3 are effectively separated, and the values of the shortest distance of cobalt-cobalt are 8.442(6) and 6.774(8) A for 1, 10.349(8) and 10.716(8) A for 2 and 6.7…

2,3,5,6-Tetrakis(2-pyridyl)pyrazine (tppz)-containing iron(II) complexes: Syntheses and crystal structures

Abstract The preparation and crystal structure of two iron(II) complexes of formula PPh4-mer-[Fe(tppz)(CN)3] · 7H2O (1) and [Fe(tppz)2][Fe(NCS)4] (2) [tppz = 2,3,5,6-tetrakis(2-pyridyl)pyrazine; PPh 4 + = tetraphenylphosphonium cation ] are reported here. The structure of 1 consists of mononuclear mer-tricyano[2,3,5,6-tetrakis(2-pyridyl)pyrazine]ferrate(II) anions, tetraphenylphosphonium cations and crystallization water molecules. Three carbon atoms from three cyanide groups in a mer arrangement and three nitrogen atoms from a tridentate tppz ligand build a somewhat distorted octahedral surrounding around the iron atom in 1. The values of the Fe–C [1.925(6)–1.947(5) A] and Fe–N [1.870(4)–1…

4,2-Ribbon like ferromagnetic cyano-bridged FeIII2NiII chains: a magneto-structural study

The low-spin iron(III) complex AsPh(4)[Fe(III)(bpy)(CN)(4)].CH(3)CN (1) [AsPh(4) = tetraphenylarsonium cation] and the heterobimetallic chains [{Fe(III)(L)(CN)(4)}(2)Ni(II)(H(2)O)(2)].4H(2)O with L = bpy (2) and phen (3) [bpy = 2,2'-bipyridine and phen = 1,10-phenanthroline] have been prepared and their structures determined by X-ray diffraction methods. The structure of 1 consists of mononuclear [Fe(bpy)(CN)(4)](-) anions, tetraphenylarsonium cations and acetonitrile molecules of crystallization. The iron(III) is hexacoordinated with two nitrogen atoms of the bidentate bpy and four carbon atoms of four terminal cyanide groups building a distorted octahedral surrounding around the metal ato…

New Magnetic Thin Film Hybrid Materials Built by the Incorporation of Octanickel(II)-oxamato Clusters Between Clay Mineral Platelets

We report on a new method based on the combination of Langmuir-Schaefer deposition with self-assembly to insert highly anisotropic Ni(8) molecules in a hybrid organic-inorganic nanostructure. Spectroscopic, crystallographic, and magnetic data prove the successful insertion of the guest cationic molecule between templating clay platelets. These results open a new route toward the highly controlled fabrication of tailored functional organic-inorganic nanomaterials.

Synthesis, crystal structures and magnetic properties of cyanide- and phenolate-bridged [MIIINiII]2tetranuclear complexes (M = Fe and Cr)

The binuclear complex NiII2L(H2O)2(ClO4)2 (1) and the neutral tetranuclear bimetallic compounds [{MIII(phen)(CN)4}2{NiII2L(H2O)2}]·2CH3CN with M = Fe (2) and Cr (3) [H2L = 11,23-dimethyl-3,7,15,19-tetraazatricyclo[19.3.1.19,13]hexacosa-2,7,9,11,13(26),14,19,21(25),22,24-decaene-25,26-diol] have been synthesized and the structures of 2 and 3 determined by single crystal X-ray diffraction. 2 and 3 are isostructural compounds whose structure is made up of centrosymmetric binuclear cations [Ni2(L)(H2O)2]2+ and two peripheral [M(phen)(CN)4]− anions [M = Fe (2) and Cr (3)] acting as monodentate ligands towards the nickel atoms through one of their four cyanide nitrogen atoms. The environment of t…

Design of single chain magnets through cyanide-bearing six-coordinate complexes

Abstract The design and preparation of stable cyanide-bearing six-coordinate complexes of formula [MIII(L)(CN)x](x + l − m)− (M = trivalent transition metal ion and L = polydentate blocking ligand) are summarized here. Their use as ligands towards either fully hydrated metal ions or coordinatively unsaturated preformed species, to afford a wide variety of low-dimensional metal assemblies whose nuclearity, dimensionality and magnetic properties can be tuned, is also reviewed. Special emphasis is put on the appropriate choice of the end-cap ligand L whose denticity determines the number of coordinated cyanide groups in the mononuclear precursors. Among the different new spin topologies obtain…

New 3d–4f supramolecular systems constructed by [Fe(bipy)(CN)4]− and partially blocked lanthanide cations

Abstract The reaction of acetonitrile (1–5) and mixed acetonitrile/water 1:1 (6–9) solutions containing the cyanide-bearing [Fe(bipy)(CN)4]− building block (bipy = 2,2′-bipyridine) and the partially blocked [Ln(bpym)]3+ cation (Ln = lanthanide trivalent cation and bpym = 2,2′-bipyrimidine) has afforded two new families of 3d–4f supramolecular assemblies of formula [Ln(bpym)(NO3)2(H2O)3][Fe(bipy)(CN)4] · H2O · CH3CN [Ln = Sm (1), Gd (2), Tb (3), Dy (4) and Ho (5)] and [Ln(bpym)(NO3)2(H2O)4][Fe(bipy)(CN)4] [Ln = Pr (6), Nd (7), Sm (8), Gd (9)]. They crystallize in the P21/c (1–5) and P2/c (6–9) space groups and their structures are made up of [Fe(bipy)(CN)4]− anions (1–9) and [Ln(bpym)(NO3)2(…

[Mn2(bipym)(H2O)8]4+and [Fe(bipy)(CN)4]−as building blocks in designing novel bipym- and cyanide-bridged heterobimetallic complexes (bipym = 2,2′-bipyrimidine and bipy = 2,2′-bipyridine)

Two new cyano complexes, K[Fe(bipy)(CN)4]·H2O (1) and (μ-bipym)[Mn(H2O)3{Fe(bipy)(CN)4}]2[Fe(bipy)(CN)4]2·12H2O (2), have been synthesised and their structures determined by single-crystal X-ray diffraction. Complex 1 is made up of mononuclear [Fe(bipy)(CN)4]− anions, potassium cations and water molecules of crystallization. The iron(III) is six-coordinated, being surrounded by two nitrogen atoms of a chelating bipy and four carbon atoms of four cyanide groups [Fe–N and Fe–C 1.991(3)–1.990(3) and 1.958(5)–1.914(5) A, respectively]. Complex 2 consists of centrosymmetric tetranuclear (μ-bipym)[Fe(H2O)3{Fe(bipy)(CN)4}]22+ cations, [Fe(bipy)(CN)4]− anions and water molecules of crystallization.…

Unprecedented coexistence of cyano-bridged Mn4(III)Cr(III) and Mn2(III)Cr(III) heterobimetallic complexes in one single crystal.

The penta-[{MnIII(4-MeO-salen)(H2O)(micro-CN)}4CrIII(CN)2]+ and trinuclear [{MnIII(4-MeO-salen)(H2O)(micro-CN)}2CrIII(CN)4](-) units coexist in 1 with weak antiferromagnetic interactions which are overcome by a dc magnetic field of 2.5 T.

Molecular Engineering To Control the Magnetic Interaction between Single-Chain Magnets Assembled in a Two-Dimensional Network

International audience; Two two-dimensional (2D) systems having the formula [{Fe-III(dmbpy)(CN)(4)}(2)(CoL)-L-II](n) [L = pyetNO (1), tvpNO (2)] and consisting of single-chain magnets connected through organic ligands (L) have been prepared, and their magnetic properties have been investigated. The overall magnetic behavior depends on the capacity of the organic pillars to transmit long-range magnetic interactions. 1 is the first example of a 2D compound exhibiting double relaxation of the magnetization, whereas 2 behaves as a metamagnet.

Syntheses, crystal structures and magnetic properties of mono- and polynuclear [bis(2-arylcarbonyl)amidate]copper(II) complexes

Abstract Five copper(II) complexes of formulas [Cu(bpcam)(CN)(H2O)] (1), [Cu(bpcam)(N3)(H2O)]2 (2), [Cu(bpcam)(NCS)(H2O)] (3), [Cu(bpcam)(dca)(H2O)]2 (4) and [Cu(bpca)(tcm)]n (5) [bpcam = bis(2-pyrimidylcarbonyl)amidate, bpca = bis(2-pyridylcarbonyl)amidate, dca = dicyanamide and tcm = tricyanomethanide] have been prepared and their structures determined by single crystal X-ray diffraction. Compounds 1 and 3 are mononuclear species where each copper atom is five coordinated with a tridentate bpcam and a terminally bound cyanide (1)/thiocyanate (3) ligands creating a basal plane with a water molecule in the axial position of a distorted square pyramid. Compound 2 is made of neutral di-μ-1,1-…

Synthesis and crystal structure of the low-spin iron(II) complex [Fe(bpz)3](ClO4)2·H2O (bpz=2,2′-bipyrazine)

Abstract The crystal structure of the title compound [Fe(bpz) 3 ](ClO 4 ) 2  · H 2 O (bpz=2,2 ′ -bipyrazine) has been determined by a single crystal X-ray diffraction study at 293(2) K. The complex is monoclinic, P 2 1 / c , a =17.263(3), b =9.983(2), c =17.921(4) A, β =107.94(3)°, V =2938.3(10) A 3 , Z =4, R =0.073 and R w =0.118. The structure is made up of tris-chelated [Fe(bpz) 3 ] 2+ cations, uncoordinated perchlorate anions and crystallization water molecules. The iron atom exhibits a FeN 6 distorted octahedral geometry with average Fe–N bond length and N–Fe–N bidentate angle of 1.962(5) A and 81.6(2)°. The value of the Fe–N bond distance and that of the room temperature magnetic mome…

Electroswitching of the single-molecule magnet behaviour in an octahedral spin crossover cobalt(ii) complex with a redox-active pyridinediimine ligand

Thermal-assisted spin crossover and field-induced slow magnetic relaxation coexist in the solid state for the mononuclear cobalt(II) complex with the non-innocent 2,6-bis(N-4-methoxyphenylformimidoyl)pyridine ligand. One-electron oxidation of the paramagnetic low-spin CoII ion (SCo = 1/2) to the diamagnetic low-spin CoIII ion (SCo = 0) leads to the electroswitching of the slow magnetic relaxation in acetonitrile solution.

[MIII(bpym)(CN)4]−: a suitable building block to design ferrimagnetic cyano-bridged heterobimetallic chains (M = Fe, Cr; bpym = 2,2′-bypyrimidine)

Two cyano-bridged M(III)Mn(III) [M = Fe () and Cr ()] ferrimagnetic chains are reported; exhibits metamagnetism with two critical fields of 1250 G and 2.0 T which correspond to the overcoming by the applied dc field of the inter- and intrachain magnetic interactions, respectively.

Magnetic coupling in discrete cyano-bridged Mn(III)-Fe(III) motifs: synthesis, crystal structure, magnetic properties and theoretical study.

The preparation, crystal structures and magnetic properties of the heterobimetallic complexes of formula [Mn(III)(n-MeOsalen)(H(2)O)(mu-CN)Fe(III)(bpym)(CN)(3)]·mH(2)O with n = m = 3 (1) and n = 4 and m = 2 (2) [n-MeOsalen(2-) = N,N'-ethylenebis(n-methoxysalicylideneiminate) dianion and bpym = 2,2'-bipyrimidine] are reported. 1 and 2 are dinuclear neutral species where the cyano-bearing low-spin unit [Fe(III)(bpym)(CN)(4)](-) acts as a monodentate ligand towards the [Mn(III)(SB)(solv)(x)](+) entity (SB = tetradentate Schiff-base) through one of its four cyano groups. Adjacent heterobimetallic units are interlinked through hydrogen bonds involving the coordinated water molecule of one dinucl…

Design of single cyanide-bridged tetranuclear bimetallic rectangles exhibiting ferromagnetic coupling

Abstract The cyanide-bridged tetranuclear bimetallic rectangles ( XPh 4 ) 4 [ Fe 2 III Cu 2 II ( μ - CN ) 4 ( CN ) 8 ( L ) 2 ] · n H 2 O [X = P (1) and As (2); L = bpcam (1) and bpca (2); n = 4 (1) and 0 (2)] have been prepared and their crystal structures were characterized by single crystal X-ray diffraction; 1 exhibits intramolecular ferromagnetic interactions (J1 = +3.7 cm−1 and J2 = +7.0 cm−1, H = - J 1 [ S Fe ( 1 ) · S Cu ( 1 ) + S Fe ( 1 a ) · S Cu ( 1 a ) ] − J 2 [ S Fe ( 1 ) · S Cu ( 1 a ) + S Fe ( 1 a ) · S Cu ( 1 ) ] + D [ S Fe ( 1 ) z 2 + S Fe ( 1 a ) z 2 ] ) leading to a low-lying S = 2 spin state.

TTF charge transfer salts containing cyanometallate anions [M(phen)(CN)4]− (M=Cr or Fe; phen=1,10-phenanthroline)

Abstract Two new charge transfer salts of TTF with the counter anions [M(phen)(CN) 4 ] − (phen = 1,10-phenanthroline, M = Cr ( I ) and Fe ( II )) are described. The structures consist of alternating stacks of dimerised TTF + cations and [M(phen)(CN) 4 ] − anions and they are linked together by many short S⋯S contacts and hydrogen bonds. Within the organic stack, two dimerised TTF + cations are arranged in a slipped face-to-face mode with short intra-dimer and long inter-dimer S⋯S distances. Strong antiferromagnetic exchange was found in the TTF + dimers. Conductivity measurements show that compound I is a semiconductor.

[Criii(L)(CN)4]−: a new building block in designing cyanide-bridged 4,2-ribbon-like chains {[Criii(L)(CN)4]2Mn(H2O)2}·nH2O [L = 2-aminomethylpyridine (n = 6) and 1,10-phenanthroline (n = 4)]

The preparation, X-ray crystallography and magnetic study of compounds PPh4[Cr(ampy)(CN)4]·H2O (1), PPh4[Cr(phen)(CN)4]·H2O·CH3OH (2), {[Cr(ampy)(CN)4]2Mn(H2O)2}·6H2O (3) and {[Cr(phen)(CN)4]2Mn(H2O)2}·4H2O (4), with PPh4+ = tetraphenylphosphonium cation, ampy = 2-aminomethylpyridine and phen = 1,10-phenanthroline, are reported here. 1 and 2 are mononuclear complexes whereas 3 and 4 are 4,2-ribbon-like bimetallic chains. The magnetic properties of 1–4 were investigated in the temperature range 1.9–300 K. A quasi Curie law behaviour for a magnetically isolated spin quartet is observed for 1 and 2. Compounds 3 and 4 are ferrimagnetic CrIII2MnII chains, which exhibit a metamagnetic behaviour, …

Cyanide-bridged Fe(III)–Co(II) bis double zigzag chains with a slow relaxation of the magnetisation

Reaction of [FeIII(bipy)(CN)4]¯ with fully solvated MII cations [M = Co (1) and Mn (2)] produces the isostructural bis double zigzag chains [[FeIII(bipy)(CN)4]2MII(H2O)]·MeCN·1/2H2O; 1 exhibits intrachain ferromagnetic and interchain antiferromagnetic couplings, slow magnetic relaxation and hysteresis effects. Luminita Marilena, Toma, Luminita.Toma@uv.es ; Lescouezec, Alain Francois Rodri, Alain.Lescouezec@uv.es ; Lloret Pastor, Francisco, Francisco.Lloret@uv.es ; Julve Olcina, Miguel, Miguel.Julve@uv.es

CCDC 903521: Experimental Crystal Structure Determination

Related Article: Diana Visinescu, Luminita Marilena Toma, Oscar Fabelo, Catalina Ruiz-Pérez, Francesc Lloret, and Miguel Julve|2013|Inorg.Chem.|52|1525|doi:10.1021/ic302278q

CCDC 903522: Experimental Crystal Structure Determination

Related Article: Diana Visinescu, Luminita Marilena Toma, Oscar Fabelo, Catalina Ruiz-Pérez, Francesc Lloret, and Miguel Julve|2013|Inorg.Chem.|52|1525|doi:10.1021/ic302278q

CCDC 903520: Experimental Crystal Structure Determination

Related Article: Diana Visinescu, Luminita Marilena Toma, Oscar Fabelo, Catalina Ruiz-Pérez, Francesc Lloret, and Miguel Julve|2013|Inorg.Chem.|52|1525|doi:10.1021/ic302278q

CCDC 903519: Experimental Crystal Structure Determination

Related Article: Diana Visinescu, Luminita Marilena Toma, Oscar Fabelo, Catalina Ruiz-Pérez, Francesc Lloret, and Miguel Julve|2013|Inorg.Chem.|52|1525|doi:10.1021/ic302278q