Structure of poly-diaqua-bis(μ-4,4'-bi-1,2,4-triazole-N1,N1')-manganese(II) dinitrate dihydrate

Vreugdenhil, W.; Haasnoot, Jaap G.; Graaff, R. A. G. de; Nieuwenhuis, Heleen A.; Reefman, D.; Reedijk, J.

doi:10.1107/s0108270187091212

Cited by 8 publications

(1 citation statement)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In all of the cases, it bridges two metal ions through the nitrogen atoms occupying the 1- and 1‘-positions, with metal−metal separations of the order of 9 Å . When coordinating anions, such as NCS - , are also present, one- or two-dimensional species are obtained. ,,− For instance, [Fe(btr) 2 (NCS) 2 ]·H 2 O is a two-dimensional spin crossover compound exhibiting a well-pronounced thermal hysteresis loop with inversion temperatures found as T ↑ = 145 K in the warming mode and T ↓ = 121 K in the cooling mode . Interestingly, when the noncoordinated water molecule is released, the spin conversion is suppressed; the compound is HS in the whole temperature range.…”

Section: Discussionmentioning

confidence: 99%

Two-Step Spin Conversion for the Three-Dimensional Compound Tris(4,4‘-bis-1,2,4-triazole)iron(II) Diperchlorate

et al. 1999

View full text Add to dashboard Cite

The title compound, [Fe(btr)(3)](ClO(4))(2), has been synthesized. The investigation of its magnetic properties has revealed a low-spin <--> high-spin conversion occurring in two steps, each step involving 50% of the Fe(2+) ions. The low-temperature step is very abrupt and occurs with a thermal hysteresis whose width is about 3 K around T(1) = 184 K. The high-temperature step, centered around T(2) = 222 K, is rather gradual. Differential scanning calorimetric measurements have confirmed the occurrence of a two-step spin conversion. The enthalpy and entropy variations associated with the two steps have been found as DeltaH(1) = 5.7 kJ mol(-)(1) and DeltaS(1) = 30.1 J mol(-)(1) K(-)(1), and DeltaH(2) = 6.5 kJ mol(-)(1) and DeltaS(2) = 28.6 J mol(-)(1) K(-)(1), respectively. The crystal structure of [Fe(btr)(3)](ClO(4))(2) has been solved at three temperatures, namely, above the high-temperature step (260 K), between the two steps (190 K), and below the low-temperature step (150 K). The compound crystallizes in the trigonal system, space group R&thremacr;, at the three temperatures. The structure is three-dimensional. There are two Fe(2+) sites, denoted Fe1 and Fe2. Each of them is located on a 3-fold symmetry axis and an inversion center and is surrounded by six btr ligands through the nitrogen atoms occupying the 1- or 1'-positions. Each btr ligand bridges an Fe1 and an Fe2 site, with an Fe1-Fe2 separation of 8.67 Å at 260 K. The perchlorate anions are located in the voids of the three-dimensional architecture and are hydrogen bonded to the triazole rings of the btr ligands. These anions do not interact with the Fe1 and Fe2 sites exactly in the same way. At 260 K, both the Fe1 and Fe2 sites are high-spin (HS) with Fe-N bond lengths of 2.161(3) and 2.164(3) Å, respectively. At 190 K, the Fe1 site remains HS while the Fe2 site is low-spin (LS) with Fe-N bond lengths of 2.007(3) Å. Finally, at 150 K, both the Fe1 and Fe2 sites are LS with Fe-N bond lengths of 1.987(5) and 1.994(5) Å, respectively. It turns out that the two-step spin conversion is associated with the presence of two slightly different Fe(2+) sites. The spin conversion regime has also been followed by Mössbauer spectroscopy. These findings have been discussed and compared to the previously reported cases of two-step spin conversions.

show abstract

Section: Discussionmentioning

confidence: 99%

Two-Step Spin Conversion for the Three-Dimensional Compound Tris(4,4‘-bis-1,2,4-triazole)iron(II) Diperchlorate

et al. 1999

View full text Add to dashboard Cite

show abstract

Synthesis and Characterisation of Coordination Polymers of Cu^II and Zn^II with 1,3‐Bis(1,2,3,4‐tetrazol‐2‐yl)propane − Rotational Freedom of the Donor Group Favours Structural Diversification

Bronisz

2004

Eur J Inorg Chem

View full text Add to dashboard Cite

The novel bidentate ligand 1,3-bis(1,2,3,4-tetrazol-2-yl)propane (pbtz), which possesses a flexible spacer, was synthesised in order to investigate the influence of the flexibility of ligand molecules on the architecture of coordination polymers. For that purpose the reactions between pbtz and M(ClO 4 ) 2 ·6H 2 O salts (M = Cu II and Zn II ) were performed. The complexes [{Cu(pbtz) 3 }(ClO 4 ) 2 ] ϱ and [{Zn(pbtz) 3 }-(ClO 4 ) 2 ·2EtOH] ϱ were characterised by IR and UV/Vis spectroscopy and their crystal structures were determined by single-crystal X-ray diffraction measurements. In both compounds the pbtz ligand molecules act as N4,N4Ј connectors bridging the central atoms, and the 2-substituted tetrazole rings coordinate in a monodentate fashion to the central atoms forming M(tetrazole) 6 cores. [{Cu(pbtz) 3 }(ClO 4 ) 2 ] ϱ was isolated as a 1D coordination polymer. The copper(II) ions are triply bridged by ligand molecules, leading to the formation

show abstract

Aromatic nitrogen heterocycles as bridging ligands; a survey

Steel

1990

Coordination Chemistry Reviews

312

127

View full text Add to dashboard Cite

Structure of poly-diaqua-bis(μ-4,4'-bi-1,2,4-triazole-N1,N1')-manganese(II) dinitrate dihydrate

Cited by 8 publications

References 3 publications

Two-Step Spin Conversion for the Three-Dimensional Compound Tris(4,4‘-bis-1,2,4-triazole)iron(II) Diperchlorate

Two-Step Spin Conversion for the Three-Dimensional Compound Tris(4,4‘-bis-1,2,4-triazole)iron(II) Diperchlorate

Synthesis and Characterisation of Coordination Polymers of Cu^II and Zn^II with 1,3‐Bis(1,2,3,4‐tetrazol‐2‐yl)propane − Rotational Freedom of the Donor Group Favours Structural Diversification

Aromatic nitrogen heterocycles as bridging ligands; a survey

Contact Info

Product

Resources

About

Structure of poly-diaqua-bis(μ-4,4'-bi-1,2,4-triazole-N1,N1')-manganese(II) dinitrate dihydrate

Cited by 8 publications

References 3 publications

Two-Step Spin Conversion for the Three-Dimensional Compound Tris(4,4‘-bis-1,2,4-triazole)iron(II) Diperchlorate

Two-Step Spin Conversion for the Three-Dimensional Compound Tris(4,4‘-bis-1,2,4-triazole)iron(II) Diperchlorate

Synthesis and Characterisation of Coordination Polymers of CuII and ZnII with 1,3‐Bis(1,2,3,4‐tetrazol‐2‐yl)propane − Rotational Freedom of the Donor Group Favours Structural Diversification

Aromatic nitrogen heterocycles as bridging ligands; a survey

Contact Info

Product

Resources

About

Synthesis and Characterisation of Coordination Polymers of Cu^II and Zn^II with 1,3‐Bis(1,2,3,4‐tetrazol‐2‐yl)propane − Rotational Freedom of the Donor Group Favours Structural Diversification