Structure and Properties of Tetracyanomanganate(II), [MnII(CN)4]2−, The First Paramagnetic Tetrahedral Cyanometalate Complex

Buschmann, Wayne E.; Arif, Atta M.; Miller, Joel S.

doi:10.1002/(sici)1521-3773(19980403)37:6<781::aid-anie781>3.0.co;2-z

Cited by 40 publications

(18 citation statements)

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“…The structure of [PPN][C 4 N 4 ] was determined from a single-crystal X-ray diffraction study. The [PPN] + cation shows bond lengths (P−N = 1.583 Å) and angles (P−N−P = 136.2°) typical of this cation. ,,7c,12b [C 4 N 4 ] - , 3 , is planar within experimental error and is positionally disordered over four equivalent sites, Figure . At first glance, the molecule appears to be isomorphous to TCNE (tetracyanoethylene) or [TCNE] •- , but has different ν CN absorptions as well as a deep red color.…”

Section: Resultsmentioning

confidence: 91%

“…Both photochemical 5 and thermal decomposition of [Mn IV (CN) 6 ] 2- lead to the formation of [Mn II (CN) 4 ] 2- ( 1 ), the first member of a new class of paramagnetic, tetrahedral, and coordinatively unsaturated cyanometalates. This result is unusual since percyano complexes of the first-row transition metals are well-known to favor coordinatively saturated octahedral geometries. , Occasionally, however, there are deviations from this trend.…”

Section: Introductionmentioning

confidence: 99%

“…All known homoleptic cyano complexes are low-spin; , however, virtually all known tetrahedral metal complexes are high-spin resulting from the decreased crystal field stabilization with respect to octahedral complexes, although a few are low spin . From magnetic susceptibility and electron paramagnetic resonance (EPR) studies, it was unambiguously determined that [Mn(CN) 4 ] 2- is indeed high-spin ( S = 5 / 2 ) with an essentially temperature-independent moment of 5.99 μ B (5.92 μ B predicted) and a Curie θ value of 0 K …”

Section: Introductionmentioning

confidence: 99%

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Tetracyanomanganate(II) and Its Salts of Divalent First-Row Transition Metal Ions

2001

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The first known paramagnetic, tetrahedral cyanide complex, [Mn(II)(CN)(4)](2)(-), is formed by the photoinduced decomposition of [Mn(IV)(CN)(6)](2)(-) in nonaqueous solutions or by thermal decomposition in the solid state. In acetonitrile or dichloromethane, photoexcitation into the ligand-to-metal charge transfer band (lambda(max) = 25 700 cm(-1), epsilon = 3700 cm(-1) M(-1)) causes the homolytic cleavage of cyanide radicals and reduction of Mn(IV). Free cyanide in dichloromethane leads to the isolation of polycyanide oligomers such as [C(12)N(12)](2)(-) and [C(4)N(4)](-), which was crystallographically characterized as the PPN(+) salt C(40)H(30)N(5)P(2): monoclinic space group = I2/a, a = 18.6314(2) A, b = 9.1926(1) A, c = 20.8006(1), beta =106.176(2) degrees, Z = 4]. In the solid state Mn(IV)-CN bond homolysis is thermally activated above 122 degrees C, according to differential scanning calorimetry measurements, leading to the reductive elimination of cyanogen. The [Mn(II)(CN)(4)](2-) ion has a dynamic solution behavior, as evidenced by its concentration-dependent electronic and electron paramagnetic spectra, that can be attributed to aggregation of the coordinatively and electronically unsaturated (four-coordinate, 13-electron) metal center. Due to dynamics and lability of [Mn(II)(CN)(4)](2-) in solution, its reaction with divalent first-row transition metal cations leads to the formation of lattice compounds with both tetrahedral and square planar local coordination geometries of the metal ions and multiple structural and cyano-linkage isomers. alpha-Mn(II)[Mn(II)(CN)(4)] has an interpenetrating sphalerite- or diamond-like network structure with a unit cell parameter of a = 6.123 A (P43m space group) while a beta-phase of this material has a noninterpenetrating disordered lattice containing tetrahedral [Mn(II)(CN)(4)](2-). Linkage isomerization or cyanide abstraction during formation results in alpha-Mn(II)[Co(II)(CN)(4)] and Mn(II)[Ni(II)(CN)(4)] lattice compounds, both containing square planar tetracyanometalate centers. alpha-Mn(II)[Co(II)(CN)(4)] is irreversibly transformed to its beta-phase in the solid state by heating to 135 degrees C, which causes a geometric isomerization of [Co(II)(CN)(4)](2)(-) from square planar (nu(CN) = 2114 cm(-1), S = (1)/(2)) to tetrahedral (nu(CN) = 2158 cm(-1), S = (3)/(2)) as evidenced by infrared and magnetic susceptibility measurements. Mn(II)[Ni(II)(CN)(4)] is the only phase formed with Ni(II) due to the high thermodynamic stability of square planar [Ni(II)(CN)(4)](2)(-).

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Section: Resultsmentioning

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Tetracyanomanganate(II) and Its Salts of Divalent First-Row Transition Metal Ions

2001

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“…In general, due to symmetry considerations, one should expect that the ligand-field splitting of the d-based molecular orbitals for a tetracoordinated transition-metal complex should be small enough so the high-spin situation is always favorable. Notable examples of this situation include the [Mn(CN) 4 ] 2– anion, with four cyanide strong-field ligands, and a magnetic moment of 4.82 μ B , only compatible with an S = 5/2 spin state . This is mostly due to the fact that both sets of orbitals in the tetrahedral ligand field splitting, e and t 2 , have a strong antibonding character (Figure ), thus leading to a small energy gap between them.…”

Section: Discussionmentioning

confidence: 99%

Theoretical Modeling of the Ligand-Tuning Effect over the Transition Temperature in Four-Coordinated Fe^II Molecules

Cirera

Ruiz

2016

Inorg. Chem.

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Spin-crossover molecules are systems of great interest due to their behavior as molecular level switches, which makes them promising candidates for nanoscale memory devices, among other applications. In this paper, we report a computational study for the calculation of the transition temperature (T(1/2)), a key physical quantity in the characterization of spin-crossover systems, for the family of tetracoordinated Fe(II) transition-metal complexes of generic formula [PhB(MesIm)3FeNPR1R2R3]. Our calculations correctly reproduce the experimentally reported decrease in the T(1/2) with an increasing size of the phosphine and allow for the prediction of the T(1/2) in new members of the family that are not reported so far. More importantly, further insight into the factors that control the fine-tuning of the T(1/2) can be obtained by direct analysis of the underlying electronic structure in terms of the relevant molecular orbitals.

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“…The preparations for many of these compounds rely upon the use of homoleptic cyanometalate complexes as building units. To give but two examples, octahedral [M(CN) 6 ] n - complexes are employed in the synthesis of cubic Prussian blue-type solids with adjustable magnetic properties, 1a-f,h,i while [M(CN) 8 ] - (M = Mo, W) complexes can be incorporated into high-nuclearity clusters with ground states of record high spin. 2e,f Thus, the synthesis of new cyanometalate complexes stands as a potent means of extending the range of accessible properties in cyano-bridged compounds . Moreover, second- and third-row transition-metal complexes, which have been less thoroughly investigated, can be expected to deliver stronger magnetic exchange coupling and greater magnetic anisotropy to the materials .…”

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confidence: 99%

New Cyanometalate Building Units: Synthesis and Characterization of [Re(CN)₇]^3- and [Re(CN)₈]^3-

2003

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Two new cyanorhenate complexes of potential utility in constructing magnetic and photomagnetic materials are reported. Reaction of (Bu4N)CN with [ReCl6]2- in acetonitrile affords yellow (Bu4N)3[Re(CN)7] (1), featuring the pentagonal bipyramidal complex [Re(CN)7]3-. The spectral and magnetic properties of 1 indicate that the complex has an S = 1/2 ground state with considerable anisotropy in the g tensor. In aqueous solution, 1 reacts with Mn2+ ions to generate the three-dimensional cyano-bridged solid [fac-Mn(H2O)3][cis-Mn(H2O)2][Re(CN)7].3H2O (2) containing diamagnetic [Re(CN)7]4-. Addition of KIO4 to the reaction solution, originally intended to prevent reduction of the rhenium during solid formation, instead yields white (Bu4N)3[Re(CN)8] (3). As crystallized in K3[Re(CN)8].2MeCN (4.2MeCN), the diamagnetic [Re(CN)8]3- complex adopts a nearly perfect square antiprismatic coordination geometry. In solution, this species behaves analogously to the isoelectronic [M(CN)8]4- (M = Mo, W) complexes, apparently converting to a dodecahedral geometry and photooxidizing under UV radiation to give paramagnetic [Re(CN)8]2-.

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Structure and Properties of Tetracyanomanganate(II), [MnII(CN)4]2−, The First Paramagnetic Tetrahedral Cyanometalate Complex

Cited by 40 publications

References 4 publications

Tetracyanomanganate(II) and Its Salts of Divalent First-Row Transition Metal Ions

Tetracyanomanganate(II) and Its Salts of Divalent First-Row Transition Metal Ions

Theoretical Modeling of the Ligand-Tuning Effect over the Transition Temperature in Four-Coordinated Fe^II Molecules

New Cyanometalate Building Units: Synthesis and Characterization of [Re(CN)₇]^3- and [Re(CN)₈]^3-

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Structure and Properties of Tetracyanomanganate(II), [MnII(CN)4]2−, The First Paramagnetic Tetrahedral Cyanometalate Complex

Cited by 40 publications

References 4 publications

Tetracyanomanganate(II) and Its Salts of Divalent First-Row Transition Metal Ions

Tetracyanomanganate(II) and Its Salts of Divalent First-Row Transition Metal Ions

Theoretical Modeling of the Ligand-Tuning Effect over the Transition Temperature in Four-Coordinated FeII Molecules

New Cyanometalate Building Units: Synthesis and Characterization of [Re(CN)7]3- and [Re(CN)8]3-

Contact Info

Product

Resources

About

Theoretical Modeling of the Ligand-Tuning Effect over the Transition Temperature in Four-Coordinated Fe^II Molecules

New Cyanometalate Building Units: Synthesis and Characterization of [Re(CN)₇]^3- and [Re(CN)₈]^3-