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Preparation, structural characterization, and decomposition studies of two new γ-octamolybdates of 4-methylpyridine.

Szymańska A, Nitek W, Rutkowska-Zbik D, Łasocha W - Monatsh. Chem. (2014)

Bottom Line: Thermal stability and decomposition studies of the obtained two new γ-octamolybdates were performed using TG/DSC and XRPD methods.Both compounds decomposed with the formation of 4-methylpyridinium β-octamolybdate.The two compounds are pseudo-polymorphs, exhibiting both striking similarities as well as significant differences in their structures and properties.

View Article: PubMed Central - PubMed

Affiliation: Jerzy Haber Institute of Catalysis and Surface Chemistry PAS, Niezapominajek 8, 30-239 Krakow, Poland.

ABSTRACT

Abstract: We synthesized two new γ-octamolybdates, and determined their crystal structures from single-crystal X-ray diffraction data. Orange-yellow tetrakis(4-methylpyridinium) bis(4-methylpyridine)-γ-octamolybdate 1 crystallizes in space group P21/c with a = 11.586(2) Å, b = 15.526(2) Å, c = 16.247(2) Å, β = 118.753(1)º, Z = 2. White tetrakis(4-methylpyridinium) bis(4-methylpyridine)-γ-octamolybdate hydrate 2 crystallizes in space group C2/c with a = 27.086(4) Å, b = 11.917(2) Å, c = 19.332(2) Å, β = 124.427(1)º, Z = 4. Results of crystal structure determinations are presented and discussed in this paper. Thermal stability and decomposition studies of the obtained two new γ-octamolybdates were performed using TG/DSC and XRPD methods. Both compounds decomposed with the formation of 4-methylpyridinium β-octamolybdate. The two compounds are pseudo-polymorphs, exhibiting both striking similarities as well as significant differences in their structures and properties.

No MeSH data available.


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Projection of the unit cell content along the b axis of 4-methylpyridinium octamolybdate(VI) hydrate (2)
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Fig5: Projection of the unit cell content along the b axis of 4-methylpyridinium octamolybdate(VI) hydrate (2)

Mentions: The unit cell of this compound contains four equivalent centrosymmetric γ-octamolybdate anions [Mo8O26]4−, and each one is directly connected to two molecules of amines by a nitrogen–molybdenum bond Mo1–N11 (2.255(2) Å). Figure 4 shows the asymmetric unit and labeling for the symmetry-independent atoms. A projection of the unit cell is presented in Fig. 5. Table 4 contains a list of bond distances. Each anion is surrounded by four 4-methylpyridinium cations. They are connected to the anions by a network of hydrogen bonds, formed by nitrogen atoms from cations and oxygen from octamolybdate anions (N21…O11 2.639 Å, N31…O5 2.685 Å). Furthermore, in the unit cell four water molecules (O14, sof = 0.5) are present, and hydrogen bonds are also formed by oxygen from water molecules and oxygen atoms from [Mo8O26]4− (O14…O12 2.794 Å, see Table 5). In contrast to 1 (where isolated clusters occur), a system of hydrogen bonds forming infinite layers parallel to (10-1) is observed. Rings (C21…C27) are arranged parallel to the plane (200), creating a double-layer build of 4-methylpyridine molecules.Fig. 4


Preparation, structural characterization, and decomposition studies of two new γ-octamolybdates of 4-methylpyridine.

Szymańska A, Nitek W, Rutkowska-Zbik D, Łasocha W - Monatsh. Chem. (2014)

Projection of the unit cell content along the b axis of 4-methylpyridinium octamolybdate(VI) hydrate (2)
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4495051&req=5

Fig5: Projection of the unit cell content along the b axis of 4-methylpyridinium octamolybdate(VI) hydrate (2)
Mentions: The unit cell of this compound contains four equivalent centrosymmetric γ-octamolybdate anions [Mo8O26]4−, and each one is directly connected to two molecules of amines by a nitrogen–molybdenum bond Mo1–N11 (2.255(2) Å). Figure 4 shows the asymmetric unit and labeling for the symmetry-independent atoms. A projection of the unit cell is presented in Fig. 5. Table 4 contains a list of bond distances. Each anion is surrounded by four 4-methylpyridinium cations. They are connected to the anions by a network of hydrogen bonds, formed by nitrogen atoms from cations and oxygen from octamolybdate anions (N21…O11 2.639 Å, N31…O5 2.685 Å). Furthermore, in the unit cell four water molecules (O14, sof = 0.5) are present, and hydrogen bonds are also formed by oxygen from water molecules and oxygen atoms from [Mo8O26]4− (O14…O12 2.794 Å, see Table 5). In contrast to 1 (where isolated clusters occur), a system of hydrogen bonds forming infinite layers parallel to (10-1) is observed. Rings (C21…C27) are arranged parallel to the plane (200), creating a double-layer build of 4-methylpyridine molecules.Fig. 4

Bottom Line: Thermal stability and decomposition studies of the obtained two new γ-octamolybdates were performed using TG/DSC and XRPD methods.Both compounds decomposed with the formation of 4-methylpyridinium β-octamolybdate.The two compounds are pseudo-polymorphs, exhibiting both striking similarities as well as significant differences in their structures and properties.

View Article: PubMed Central - PubMed

Affiliation: Jerzy Haber Institute of Catalysis and Surface Chemistry PAS, Niezapominajek 8, 30-239 Krakow, Poland.

ABSTRACT

Abstract: We synthesized two new γ-octamolybdates, and determined their crystal structures from single-crystal X-ray diffraction data. Orange-yellow tetrakis(4-methylpyridinium) bis(4-methylpyridine)-γ-octamolybdate 1 crystallizes in space group P21/c with a = 11.586(2) Å, b = 15.526(2) Å, c = 16.247(2) Å, β = 118.753(1)º, Z = 2. White tetrakis(4-methylpyridinium) bis(4-methylpyridine)-γ-octamolybdate hydrate 2 crystallizes in space group C2/c with a = 27.086(4) Å, b = 11.917(2) Å, c = 19.332(2) Å, β = 124.427(1)º, Z = 4. Results of crystal structure determinations are presented and discussed in this paper. Thermal stability and decomposition studies of the obtained two new γ-octamolybdates were performed using TG/DSC and XRPD methods. Both compounds decomposed with the formation of 4-methylpyridinium β-octamolybdate. The two compounds are pseudo-polymorphs, exhibiting both striking similarities as well as significant differences in their structures and properties.

No MeSH data available.


Related in: MedlinePlus