Hypokinesia in adolescents

Title: Hypokinesia in adolescents Objectives: The main target is, to find out how frequent and extensive the hypokinesis appears in terms of the exploratory subject. We mainly search for the relationship of high school adolescents to the physical activities, how often it's being practicised and in which kind of environment. Methods: In order to prove my thesis, we decided to use a long version of international standardized IPAQ questionnaire translated to the czech language. The exploratory sample consisted of 46 high school adolescent students. The results were afterwards analysed according to the basic statistic principles. Subsequently we compared the quantity of physical activity between boys and girls during seven days of the research. Results: The results of research apparently meet the criteria of the sufficient count of teenager activities. In the average the sample was evaluated as moderately active individuals in both gender types. Despite the negative public image in terms of quantity of youth physical activities, the actual rate meets general requirements. Boys reached the rate of 1333,8 MET- min/week, girls reached the count of 2013,9 MET-min/week. Keywords: adolescence, physical activity, lack of exercise, lifestyl

Synthesis and Characterization of Nickel(II) Phosphonate Complexes Utilizing Pyridonates and Carboxylates as Co-ligands

The synthesis and structures of five new nickel complexes containing phosphonate ligands are reported. The compounds utilize pivalic acid (HPiv) and 6-chloro-2-pyridonate (Hchp) as co-ligands with the resulting complexes being of formulas [Ni₁₀(chp)₄­(Hchp)_4.5­(O₃P^tBu)₃­(Piv)₅(HPiv)₂­(OH)₆(H₂O)_4.5]­(HNEt₃)·0.5MeCN·2.5H₂O <b>1</b>, [Ni₁₂(chp)₁₂(Hchp)₂(PhPO₃)₂­(Piv)₅(HPiv)₂­(OH)₂(H₂O)₆]­(F)·4.5MeCN·2H₂O <b>2</b>, [Ni₁₀(chp)₆(O₃PCH₂Ph)₂­(Piv)₈(F)₂­(MeCN)₄] <b>3</b>, [Ni₁₀(chp)₆­(O₃PMe)₂­(Piv)₈(F)₂ (MeCN)₄]·5MeCN·2H₂O <b>4</b>, and [Ni₁₀(chp)₆(O₃PCH₂Nap)₂­(Piv)₈(F)₂­(MeCN)₂(H₂O)₂] <b>5</b>. The metallic core of compounds <b>1</b> and <b>2</b> display tetra- and hexa-capped trigonal prismatic arrangements, while the metallic and phosphorus core of <b>3</b>, <b>4</b>, and <b>5</b> display three face-sharing octahedra. Variable temperature direct current (dc) magnetic susceptibility measurements reveal dominant antiferromagnetic exchange interactions within each cluster, with diamagnetic spin ground states found

Synthesis and Characterization of Nickel(II) Phosphonate Complexes Utilizing Pyridonates and Carboxylates as Co-ligands

The synthesis and structures of five new nickel complexes containing phosphonate ligands are reported. The compounds utilize pivalic acid (HPiv) and 6-chloro-2-pyridonate (Hchp) as co-ligands with the resulting complexes being of formulas [Ni₁₀(chp)₄­(Hchp)_4.5­(O₃P^tBu)₃­(Piv)₅(HPiv)₂­(OH)₆(H₂O)_4.5]­(HNEt₃)·0.5MeCN·2.5H₂O <b>1</b>, [Ni₁₂(chp)₁₂(Hchp)₂(PhPO₃)₂­(Piv)₅(HPiv)₂­(OH)₂(H₂O)₆]­(F)·4.5MeCN·2H₂O <b>2</b>, [Ni₁₀(chp)₆(O₃PCH₂Ph)₂­(Piv)₈(F)₂­(MeCN)₄] <b>3</b>, [Ni₁₀(chp)₆­(O₃PMe)₂­(Piv)₈(F)₂ (MeCN)₄]·5MeCN·2H₂O <b>4</b>, and [Ni₁₀(chp)₆(O₃PCH₂Nap)₂­(Piv)₈(F)₂­(MeCN)₂(H₂O)₂] <b>5</b>. The metallic core of compounds <b>1</b> and <b>2</b> display tetra- and hexa-capped trigonal prismatic arrangements, while the metallic and phosphorus core of <b>3</b>, <b>4</b>, and <b>5</b> display three face-sharing octahedra. Variable temperature direct current (dc) magnetic susceptibility measurements reveal dominant antiferromagnetic exchange interactions within each cluster, with diamagnetic spin ground states found

Single-Molecule Magnetism in Tetrametallic Terbium and Dysprosium Thiolate Cages

Metalation of ethanethiol by [{(Me₃Si)₂N}₃Ln­(μ-Cl)­Li­(thf)₃] (Ln = Gd, Tb, Dy) in thf produces the thiolate-bridged tetralanthanide compounds [Li­(thf)₄]­[Ln₄{N­(SiMe₃)₂}₄(μ-SEt)₈(μ₄-SEt)], where Ln = Gd is [Li­(thf)₄]­[<b>1</b>], Ln = Tb is [Li­(thf)₄]­[<b>2</b>], and Ln = Dy is [Li­(thf)₄]­[<b>3</b>]. Crystallographic studies reveal that the monoanions <b>1</b>–<b>3</b> are essentially isostructural, consisting of tetrametallic Ln₄ units in which the lanthanides are bridged by μ-ethanethiolate ligands and the individual lanthanide centers occupy distorted six-coordinate {LnNS₅} coordination environments. The magnetic susceptibility properties of all three compounds were measured in a static (dc) field of 1000 G: the data for the gadolinium anion <b>1</b> were reproduced by a model that suggests weak antiferromagnetic and ferromagnetic exchange, with coupling constants of <i>J</i> = −0.09 and +0.04 cm^–1 (−2<i>J</i> formalism). Magnetic susceptibility measurements in a dynamic (ac) field at various frequencies on [Li­(thf)₄]­[<b>2</b>] and [Li­(thf)₄]­[<b>3</b>], in zero dc field, reveal properties characteristic of a single-molecule magnet (SMM). Analysis of the out-of-phase magnetic susceptibility for <b>2</b> in zero applied field yielded a small anisotropy barrier of <i>U</i>_eff = 4.6 cm^–1, and a similar analysis on <b>3</b> produced <i>U</i>_eff = 46 cm^–1. Compounds [Li­(thf)₄]­[<b>2</b>] and [Li­(thf)₄]­[<b>3</b>] are rare examples of sulfur-ligated SMMs

Single-Molecule Magnetism in Tetrametallic Terbium and Dysprosium Thiolate Cages

Metalation of ethanethiol by [{(Me₃Si)₂N}₃Ln­(μ-Cl)­Li­(thf)₃] (Ln = Gd, Tb, Dy) in thf produces the thiolate-bridged tetralanthanide compounds [Li­(thf)₄]­[Ln₄{N­(SiMe₃)₂}₄(μ-SEt)₈(μ₄-SEt)], where Ln = Gd is [Li­(thf)₄]­[<b>1</b>], Ln = Tb is [Li­(thf)₄]­[<b>2</b>], and Ln = Dy is [Li­(thf)₄]­[<b>3</b>]. Crystallographic studies reveal that the monoanions <b>1</b>–<b>3</b> are essentially isostructural, consisting of tetrametallic Ln₄ units in which the lanthanides are bridged by μ-ethanethiolate ligands and the individual lanthanide centers occupy distorted six-coordinate {LnNS₅} coordination environments. The magnetic susceptibility properties of all three compounds were measured in a static (dc) field of 1000 G: the data for the gadolinium anion <b>1</b> were reproduced by a model that suggests weak antiferromagnetic and ferromagnetic exchange, with coupling constants of <i>J</i> = −0.09 and +0.04 cm^–1 (−2<i>J</i> formalism). Magnetic susceptibility measurements in a dynamic (ac) field at various frequencies on [Li­(thf)₄]­[<b>2</b>] and [Li­(thf)₄]­[<b>3</b>], in zero dc field, reveal properties characteristic of a single-molecule magnet (SMM). Analysis of the out-of-phase magnetic susceptibility for <b>2</b> in zero applied field yielded a small anisotropy barrier of <i>U</i>_eff = 4.6 cm^–1, and a similar analysis on <b>3</b> produced <i>U</i>_eff = 46 cm^–1. Compounds [Li­(thf)₄]­[<b>2</b>] and [Li­(thf)₄]­[<b>3</b>] are rare examples of sulfur-ligated SMMs

Synthesis, Structure, and Paramagnetism of Manganese(II) Iminophosphate Complexes

The coordination chemistry of the bidentate bis­(imino)­bis­(amino)­phosphate ligands [Me₃SiNP­{NR}­{N­(H)­R}₂]⁻, where R = <i>n</i>-propyl is [L¹H₂]⁻, R = cyclohexyl is [L²H₂]⁻, and R = <i>tert</i>-butyl is [L³H₂]⁻, with manganese­(II), is described. The bis­(imino)­bis­(amino)­phosphate-manganese­(II) complexes [(η⁵-Cp)­Mn­(μ-L¹H₂)]₂ (<b>1</b>), [Mn­(L²H₂)₂]·THF (<b>2</b>·THF), and [(η⁵-Cp)­Mn­(L³H₂)] (<b>3</b>) were synthesized by monodeprotonation of the respective pro-ligands by manganocene, Cp₂Mn. The molecular structures of <b>1</b>–<b>3</b> reveal that the steric demands of the ligand N-substituents play a dominant role in determining the aggregation state and overall composition of the manganese­(II) complexes. The coordination geometries of the Mn­(II) centers are six-coordinate pseudotetrahedral in <b>1</b>, four-coordinate distorted tetrahedral in <b>2</b>, and five-coordinate in <b>3</b>, resulting in formal valence electron counts of 17, 13, and 15, respectively. EPR studies of <b>1</b>–<b>3</b> at Q-band reveal high-spin manganese­(II) (<i>S</i> = ⁵/₂) in each case. In the EPR spectrum of <b>1</b>, no evidence of intramolecular magnetic exchange was found. The relative magnitudes of the axial zero-field splitting parameter, <i>D</i>, in <b>2</b> and <b>3</b> are consistent with the symmetry of the manganese environment, which are <i>D</i>_2<i>d</i> in <b>2</b> and <i>C</i>_2<i>v</i> in <b>3</b>

Wells–Dawson Cages as Molecular Refrigerants

Five clusters with the general formula [Ni₆Gd₆(μ₃-OH)₂(μ₂-OAc)₂(O₃PR)₆(O₂C^<i>t</i>Bu)₁₆], where R = methyl (<b>1</b>), phenyl (<b>2</b>), <i>n</i>-hexyl (<b>3</b>), benzyl (<b>4</b>), <i>n</i>-octyl (<b>5</b>), have been prepared. All of the clusters have a {Ni₆Gd₆P₆} core that can be related to the Wells–Dawson ion. We have also prepared analogues where the gadolinium is replaced with diamagnetic yttrium: [Ni₆Y₆(μ₃-OH)₂(μ₂-OAc)₂(O₃PR)₆(O₂C^<i>t</i>Bu)₁₆] (R = methyl (<b>6</b>), <i>n</i>-hexyl (<b>7</b>), benzyl (<b>8</b>), <i>n</i>-octyl (<b>9</b>)), allowing the magnetic exchange within the {Ni₃} units to be analyzed by modeling as the sum of two noninteracting isosceles triangles. The variation in the magnetic entropy changes for magnetization (−Δ<i>S</i>_M) among compounds <b>1</b>–<b>5</b> could be attributed not only to the molecular weight of the compounds but also to intramolecular magnetic interactions

Systematic Study of a Family of Butterfly-Like {M₂Ln₂} Molecular Magnets (M = Mg^II, Mn^III, Co^II, Ni^II, and Cu^II; Ln = Y^III, Gd^III, Tb^III, Dy^III, Ho^III, and Er^III)

A family of 3d–4f [M^II₂Ln^III₂(μ₃-OH)₂(O₂C^<i>t</i>Bu)₁₀]^2– “butterflies” (where M^II = Mg, Co, Ni, and Cu; Ln^III = Y, Gd, Tb, Dy, Ho, and Er) and [Mn^III₂Ln^III₂(μ₃-O)₂(O₂C^<i>t</i>Bu)₁₀]^2– molecules (where Ln^III = Y, Gd, Tb, Dy, Ho, and Er) has been synthesized and characterized through single-crystal X-ray diffraction, SQUID magnetometry, and ab initio calculations. All dysprosium- and some erbium-containing tetramers showed frequency-dependent maxima in the out-of-phase component of the susceptibility associated with slow relaxation of magnetization, and hence, they are single-molecule magnets (SMMs). AC susceptibility measurements have shown that the SMM behavior is entirely intrinsic to the Dy and Er sites and the magnitude of the energy barrier is influenced by the interactions between the 4f and the 3d metal. A trend is observed between the strength of the 3d-4f exchange interaction between and the maximum observed in the χ″_M(<i>T</i>)

Wells–Dawson Cages as Molecular Refrigerants

Five clusters with the general formula [Ni₆Gd₆(μ₃-OH)₂(μ₂-OAc)₂(O₃PR)₆(O₂C^<i>t</i>Bu)₁₆], where R = methyl (<b>1</b>), phenyl (<b>2</b>), <i>n</i>-hexyl (<b>3</b>), benzyl (<b>4</b>), <i>n</i>-octyl (<b>5</b>), have been prepared. All of the clusters have a {Ni₆Gd₆P₆} core that can be related to the Wells–Dawson ion. We have also prepared analogues where the gadolinium is replaced with diamagnetic yttrium: [Ni₆Y₆(μ₃-OH)₂(μ₂-OAc)₂(O₃PR)₆(O₂C^<i>t</i>Bu)₁₆] (R = methyl (<b>6</b>), <i>n</i>-hexyl (<b>7</b>), benzyl (<b>8</b>), <i>n</i>-octyl (<b>9</b>)), allowing the magnetic exchange within the {Ni₃} units to be analyzed by modeling as the sum of two noninteracting isosceles triangles. The variation in the magnetic entropy changes for magnetization (−Δ<i>S</i>_M) among compounds <b>1</b>–<b>5</b> could be attributed not only to the molecular weight of the compounds but also to intramolecular magnetic interactions

Wells–Dawson Cages as Molecular Refrigerants

Five clusters with the general formula [Ni₆Gd₆(μ₃-OH)₂(μ₂-OAc)₂(O₃PR)₆(O₂C^<i>t</i>Bu)₁₆], where R = methyl (<b>1</b>), phenyl (<b>2</b>), <i>n</i>-hexyl (<b>3</b>), benzyl (<b>4</b>), <i>n</i>-octyl (<b>5</b>), have been prepared. All of the clusters have a {Ni₆Gd₆P₆} core that can be related to the Wells–Dawson ion. We have also prepared analogues where the gadolinium is replaced with diamagnetic yttrium: [Ni₆Y₆(μ₃-OH)₂(μ₂-OAc)₂(O₃PR)₆(O₂C^<i>t</i>Bu)₁₆] (R = methyl (<b>6</b>), <i>n</i>-hexyl (<b>7</b>), benzyl (<b>8</b>), <i>n</i>-octyl (<b>9</b>)), allowing the magnetic exchange within the {Ni₃} units to be analyzed by modeling as the sum of two noninteracting isosceles triangles. The variation in the magnetic entropy changes for magnetization (−Δ<i>S</i>_M) among compounds <b>1</b>–<b>5</b> could be attributed not only to the molecular weight of the compounds but also to intramolecular magnetic interactions