10 research outputs found
Four Polyoxonibate-Based Inorganic–Organic Hybrids Assembly from Bicapped Heteropolyoxonibate with Effective Antitumor Activity
Four
novel heteropolyoxonibate-based inorganic–organic hybrids
{CuÂ(en)<sub>2</sub>}<sub>6</sub>{GeNb<sub>12</sub>V<sup>IV</sup><sub>2</sub>O<sub>42</sub>}·20H<sub>2</sub>O (<b>1</b>), {CuÂ(en)<sub>2</sub>}<sub>3</sub>K<sub>2</sub>Na<sub>4</sub>{GeNb<sub>12</sub>V<sup>IV</sup><sub>2</sub>O<sub>42</sub>}·23H<sub>2</sub>O (<b>2</b>), {CuÂ(en)<sub>2</sub>}<sub>6</sub>{SiNb<sub>12</sub>V<sup>IV</sup><sub>2</sub>O<sub>42</sub>}·18H<sub>2</sub>O (<b>3</b>), and {CuÂ(en)<sub>2</sub>}<sub>3</sub>K<sub>2</sub>Na<sub>4</sub>{SiNb<sub>12</sub>V<sup>IV</sup><sub>2</sub>O<sub>42</sub>}·19H<sub>2</sub>O (<b>4</b>) (en = ethanediamine), composed
of polyoxoanions [TNb<sub>12</sub>O<sub>40</sub>]<sup>16–</sup> (T = Si and Ge) and [CuÂ(en)<sub>2</sub>]<sup>2+</sup> building blocks,
were successfully synthesized under hydrothermal conditions by reaction
of K<sub>7</sub>HNb<sub>6</sub>O<sub>19</sub>·13H<sub>2</sub>O, CuÂ(Ac)<sub>2</sub>·3H<sub>2</sub>O, Na<sub>2</sub>VO<sub>3</sub>, Na<sub>2</sub>SiO<sub>3</sub>, or GeO<sub>2</sub> and en
molecules. Polyoxoanion [TNb<sub>12</sub>VIV<sub>2</sub>O<sub>42</sub>]<sup>12–</sup> (T = Si and Ge) can be best described as a
α-Keggin core [TNb<sub>12</sub>O<sub>40</sub>] with two [VO]
units capping on its two “opened windows”. Compounds <b>1</b> and <b>3</b> are both composed of the bicapped heteropolyoxonibate
core surrounded by a shell consisting of twelve [CuÂ(en)<sub>2</sub>]<sup>2+</sup> groups, which represent a promising structural model
toward core–shell nanostructures. Compounds <b>2</b> and <b>4</b> are also composed of a bicapped polyoxoanion [TNb<sub>12</sub>V<sup>IV</sup><sub>2</sub>O<sub>42</sub>]<sup>12–</sup> (T
= Si, Ge) decorated by three metal–organic fragments [CuÂ(en)<sub>2</sub>]<sup>2+</sup>, forming a trisupporting polyoxoanion {[CuÂ(en)<sub>2</sub>]<sub>3</sub>[TNb<sub>12</sub>O<sub>42</sub>V<sup>IV</sup><sub>2</sub>]}<sup>6–</sup>. Antitumor, electrochemical study,
and UV–vis spectra indicate that compounds <b>1</b>–<b>4</b> exhibit effective antitumor activity against SGC7901 cells
and HepG2 cells and could keep the structural integrity in this process
Four Polyoxonibate-Based Inorganic–Organic Hybrids Assembly from Bicapped Heteropolyoxonibate with Effective Antitumor Activity
Four
novel heteropolyoxonibate-based inorganic–organic hybrids
{CuÂ(en)<sub>2</sub>}<sub>6</sub>{GeNb<sub>12</sub>V<sup>IV</sup><sub>2</sub>O<sub>42</sub>}·20H<sub>2</sub>O (<b>1</b>), {CuÂ(en)<sub>2</sub>}<sub>3</sub>K<sub>2</sub>Na<sub>4</sub>{GeNb<sub>12</sub>V<sup>IV</sup><sub>2</sub>O<sub>42</sub>}·23H<sub>2</sub>O (<b>2</b>), {CuÂ(en)<sub>2</sub>}<sub>6</sub>{SiNb<sub>12</sub>V<sup>IV</sup><sub>2</sub>O<sub>42</sub>}·18H<sub>2</sub>O (<b>3</b>), and {CuÂ(en)<sub>2</sub>}<sub>3</sub>K<sub>2</sub>Na<sub>4</sub>{SiNb<sub>12</sub>V<sup>IV</sup><sub>2</sub>O<sub>42</sub>}·19H<sub>2</sub>O (<b>4</b>) (en = ethanediamine), composed
of polyoxoanions [TNb<sub>12</sub>O<sub>40</sub>]<sup>16–</sup> (T = Si and Ge) and [CuÂ(en)<sub>2</sub>]<sup>2+</sup> building blocks,
were successfully synthesized under hydrothermal conditions by reaction
of K<sub>7</sub>HNb<sub>6</sub>O<sub>19</sub>·13H<sub>2</sub>O, CuÂ(Ac)<sub>2</sub>·3H<sub>2</sub>O, Na<sub>2</sub>VO<sub>3</sub>, Na<sub>2</sub>SiO<sub>3</sub>, or GeO<sub>2</sub> and en
molecules. Polyoxoanion [TNb<sub>12</sub>VIV<sub>2</sub>O<sub>42</sub>]<sup>12–</sup> (T = Si and Ge) can be best described as a
α-Keggin core [TNb<sub>12</sub>O<sub>40</sub>] with two [VO]
units capping on its two “opened windows”. Compounds <b>1</b> and <b>3</b> are both composed of the bicapped heteropolyoxonibate
core surrounded by a shell consisting of twelve [CuÂ(en)<sub>2</sub>]<sup>2+</sup> groups, which represent a promising structural model
toward core–shell nanostructures. Compounds <b>2</b> and <b>4</b> are also composed of a bicapped polyoxoanion [TNb<sub>12</sub>V<sup>IV</sup><sub>2</sub>O<sub>42</sub>]<sup>12–</sup> (T
= Si, Ge) decorated by three metal–organic fragments [CuÂ(en)<sub>2</sub>]<sup>2+</sup>, forming a trisupporting polyoxoanion {[CuÂ(en)<sub>2</sub>]<sub>3</sub>[TNb<sub>12</sub>O<sub>42</sub>V<sup>IV</sup><sub>2</sub>]}<sup>6–</sup>. Antitumor, electrochemical study,
and UV–vis spectra indicate that compounds <b>1</b>–<b>4</b> exhibit effective antitumor activity against SGC7901 cells
and HepG2 cells and could keep the structural integrity in this process
Four Polyoxonibate-Based Inorganic–Organic Hybrids Assembly from Bicapped Heteropolyoxonibate with Effective Antitumor Activity
Four
novel heteropolyoxonibate-based inorganic–organic hybrids
{CuÂ(en)<sub>2</sub>}<sub>6</sub>{GeNb<sub>12</sub>V<sup>IV</sup><sub>2</sub>O<sub>42</sub>}·20H<sub>2</sub>O (<b>1</b>), {CuÂ(en)<sub>2</sub>}<sub>3</sub>K<sub>2</sub>Na<sub>4</sub>{GeNb<sub>12</sub>V<sup>IV</sup><sub>2</sub>O<sub>42</sub>}·23H<sub>2</sub>O (<b>2</b>), {CuÂ(en)<sub>2</sub>}<sub>6</sub>{SiNb<sub>12</sub>V<sup>IV</sup><sub>2</sub>O<sub>42</sub>}·18H<sub>2</sub>O (<b>3</b>), and {CuÂ(en)<sub>2</sub>}<sub>3</sub>K<sub>2</sub>Na<sub>4</sub>{SiNb<sub>12</sub>V<sup>IV</sup><sub>2</sub>O<sub>42</sub>}·19H<sub>2</sub>O (<b>4</b>) (en = ethanediamine), composed
of polyoxoanions [TNb<sub>12</sub>O<sub>40</sub>]<sup>16–</sup> (T = Si and Ge) and [CuÂ(en)<sub>2</sub>]<sup>2+</sup> building blocks,
were successfully synthesized under hydrothermal conditions by reaction
of K<sub>7</sub>HNb<sub>6</sub>O<sub>19</sub>·13H<sub>2</sub>O, CuÂ(Ac)<sub>2</sub>·3H<sub>2</sub>O, Na<sub>2</sub>VO<sub>3</sub>, Na<sub>2</sub>SiO<sub>3</sub>, or GeO<sub>2</sub> and en
molecules. Polyoxoanion [TNb<sub>12</sub>VIV<sub>2</sub>O<sub>42</sub>]<sup>12–</sup> (T = Si and Ge) can be best described as a
α-Keggin core [TNb<sub>12</sub>O<sub>40</sub>] with two [VO]
units capping on its two “opened windows”. Compounds <b>1</b> and <b>3</b> are both composed of the bicapped heteropolyoxonibate
core surrounded by a shell consisting of twelve [CuÂ(en)<sub>2</sub>]<sup>2+</sup> groups, which represent a promising structural model
toward core–shell nanostructures. Compounds <b>2</b> and <b>4</b> are also composed of a bicapped polyoxoanion [TNb<sub>12</sub>V<sup>IV</sup><sub>2</sub>O<sub>42</sub>]<sup>12–</sup> (T
= Si, Ge) decorated by three metal–organic fragments [CuÂ(en)<sub>2</sub>]<sup>2+</sup>, forming a trisupporting polyoxoanion {[CuÂ(en)<sub>2</sub>]<sub>3</sub>[TNb<sub>12</sub>O<sub>42</sub>V<sup>IV</sup><sub>2</sub>]}<sup>6–</sup>. Antitumor, electrochemical study,
and UV–vis spectra indicate that compounds <b>1</b>–<b>4</b> exhibit effective antitumor activity against SGC7901 cells
and HepG2 cells and could keep the structural integrity in this process
Hydroxide Ligands Cooperate with Catalytic Centers in Metal–Organic Frameworks for Efficient Photocatalytic CO<sub>2</sub> Reduction
Converting CO<sub>2</sub> into fuels via photochemical reactions
relies on highly efficient and selective catalysts. We demonstrate
that the catalytic active metal center can cooperate with neighboring
hydroxide ligands to boost the photocatalytic CO<sub>2</sub> reduction.
Six cobalt-based metal–organic frameworks (MOFs) with different
coordination environments are studied at the same reaction condition
(photosensitizer, electron donor, water/organic mixed solvent, and
visible light). In pure CO<sub>2</sub> at 1.0 atm, the MOFs bearing
μ-OH<sup>–</sup> ligands neighboring the open Co centers
showed CO selectivities and turnover frequencies (TOFs) up to 98.2%
and 0.059 s<sup>–1</sup>, respectively. More importantly, their
TOFs reduced only ca. 20% when the CO<sub>2</sub> partial pressure
was reduced to 0.1 atm, while other MOFs reduced by at least 90%.
Periodic density functional theory calculations and isotope tracing
experiments showed that the μ-OH<sup>–</sup> ligands
serve not only as strong hydrogen-bonding donors to stabilize the
initial Co–CO<sub>2</sub> adduct but also local proton sources
to facilitate the C–O bond breaking
Four Polyoxonibate-Based Inorganic–Organic Hybrids Assembly from Bicapped Heteropolyoxonibate with Effective Antitumor Activity
Four
novel heteropolyoxonibate-based inorganic–organic hybrids
{CuÂ(en)<sub>2</sub>}<sub>6</sub>{GeNb<sub>12</sub>V<sup>IV</sup><sub>2</sub>O<sub>42</sub>}·20H<sub>2</sub>O (<b>1</b>), {CuÂ(en)<sub>2</sub>}<sub>3</sub>K<sub>2</sub>Na<sub>4</sub>{GeNb<sub>12</sub>V<sup>IV</sup><sub>2</sub>O<sub>42</sub>}·23H<sub>2</sub>O (<b>2</b>), {CuÂ(en)<sub>2</sub>}<sub>6</sub>{SiNb<sub>12</sub>V<sup>IV</sup><sub>2</sub>O<sub>42</sub>}·18H<sub>2</sub>O (<b>3</b>), and {CuÂ(en)<sub>2</sub>}<sub>3</sub>K<sub>2</sub>Na<sub>4</sub>{SiNb<sub>12</sub>V<sup>IV</sup><sub>2</sub>O<sub>42</sub>}·19H<sub>2</sub>O (<b>4</b>) (en = ethanediamine), composed
of polyoxoanions [TNb<sub>12</sub>O<sub>40</sub>]<sup>16–</sup> (T = Si and Ge) and [CuÂ(en)<sub>2</sub>]<sup>2+</sup> building blocks,
were successfully synthesized under hydrothermal conditions by reaction
of K<sub>7</sub>HNb<sub>6</sub>O<sub>19</sub>·13H<sub>2</sub>O, CuÂ(Ac)<sub>2</sub>·3H<sub>2</sub>O, Na<sub>2</sub>VO<sub>3</sub>, Na<sub>2</sub>SiO<sub>3</sub>, or GeO<sub>2</sub> and en
molecules. Polyoxoanion [TNb<sub>12</sub>VIV<sub>2</sub>O<sub>42</sub>]<sup>12–</sup> (T = Si and Ge) can be best described as a
α-Keggin core [TNb<sub>12</sub>O<sub>40</sub>] with two [VO]
units capping on its two “opened windows”. Compounds <b>1</b> and <b>3</b> are both composed of the bicapped heteropolyoxonibate
core surrounded by a shell consisting of twelve [CuÂ(en)<sub>2</sub>]<sup>2+</sup> groups, which represent a promising structural model
toward core–shell nanostructures. Compounds <b>2</b> and <b>4</b> are also composed of a bicapped polyoxoanion [TNb<sub>12</sub>V<sup>IV</sup><sub>2</sub>O<sub>42</sub>]<sup>12–</sup> (T
= Si, Ge) decorated by three metal–organic fragments [CuÂ(en)<sub>2</sub>]<sup>2+</sup>, forming a trisupporting polyoxoanion {[CuÂ(en)<sub>2</sub>]<sub>3</sub>[TNb<sub>12</sub>O<sub>42</sub>V<sup>IV</sup><sub>2</sub>]}<sup>6–</sup>. Antitumor, electrochemical study,
and UV–vis spectra indicate that compounds <b>1</b>–<b>4</b> exhibit effective antitumor activity against SGC7901 cells
and HepG2 cells and could keep the structural integrity in this process
Four Polyoxonibate-Based Inorganic–Organic Hybrids Assembly from Bicapped Heteropolyoxonibate with Effective Antitumor Activity
Four
novel heteropolyoxonibate-based inorganic–organic hybrids
{CuÂ(en)<sub>2</sub>}<sub>6</sub>{GeNb<sub>12</sub>V<sup>IV</sup><sub>2</sub>O<sub>42</sub>}·20H<sub>2</sub>O (<b>1</b>), {CuÂ(en)<sub>2</sub>}<sub>3</sub>K<sub>2</sub>Na<sub>4</sub>{GeNb<sub>12</sub>V<sup>IV</sup><sub>2</sub>O<sub>42</sub>}·23H<sub>2</sub>O (<b>2</b>), {CuÂ(en)<sub>2</sub>}<sub>6</sub>{SiNb<sub>12</sub>V<sup>IV</sup><sub>2</sub>O<sub>42</sub>}·18H<sub>2</sub>O (<b>3</b>), and {CuÂ(en)<sub>2</sub>}<sub>3</sub>K<sub>2</sub>Na<sub>4</sub>{SiNb<sub>12</sub>V<sup>IV</sup><sub>2</sub>O<sub>42</sub>}·19H<sub>2</sub>O (<b>4</b>) (en = ethanediamine), composed
of polyoxoanions [TNb<sub>12</sub>O<sub>40</sub>]<sup>16–</sup> (T = Si and Ge) and [CuÂ(en)<sub>2</sub>]<sup>2+</sup> building blocks,
were successfully synthesized under hydrothermal conditions by reaction
of K<sub>7</sub>HNb<sub>6</sub>O<sub>19</sub>·13H<sub>2</sub>O, CuÂ(Ac)<sub>2</sub>·3H<sub>2</sub>O, Na<sub>2</sub>VO<sub>3</sub>, Na<sub>2</sub>SiO<sub>3</sub>, or GeO<sub>2</sub> and en
molecules. Polyoxoanion [TNb<sub>12</sub>VIV<sub>2</sub>O<sub>42</sub>]<sup>12–</sup> (T = Si and Ge) can be best described as a
α-Keggin core [TNb<sub>12</sub>O<sub>40</sub>] with two [VO]
units capping on its two “opened windows”. Compounds <b>1</b> and <b>3</b> are both composed of the bicapped heteropolyoxonibate
core surrounded by a shell consisting of twelve [CuÂ(en)<sub>2</sub>]<sup>2+</sup> groups, which represent a promising structural model
toward core–shell nanostructures. Compounds <b>2</b> and <b>4</b> are also composed of a bicapped polyoxoanion [TNb<sub>12</sub>V<sup>IV</sup><sub>2</sub>O<sub>42</sub>]<sup>12–</sup> (T
= Si, Ge) decorated by three metal–organic fragments [CuÂ(en)<sub>2</sub>]<sup>2+</sup>, forming a trisupporting polyoxoanion {[CuÂ(en)<sub>2</sub>]<sub>3</sub>[TNb<sub>12</sub>O<sub>42</sub>V<sup>IV</sup><sub>2</sub>]}<sup>6–</sup>. Antitumor, electrochemical study,
and UV–vis spectra indicate that compounds <b>1</b>–<b>4</b> exhibit effective antitumor activity against SGC7901 cells
and HepG2 cells and could keep the structural integrity in this process
Four Polyoxonibate-Based Inorganic–Organic Hybrids Assembly from Bicapped Heteropolyoxonibate with Effective Antitumor Activity
Four
novel heteropolyoxonibate-based inorganic–organic hybrids
{CuÂ(en)<sub>2</sub>}<sub>6</sub>{GeNb<sub>12</sub>V<sup>IV</sup><sub>2</sub>O<sub>42</sub>}·20H<sub>2</sub>O (<b>1</b>), {CuÂ(en)<sub>2</sub>}<sub>3</sub>K<sub>2</sub>Na<sub>4</sub>{GeNb<sub>12</sub>V<sup>IV</sup><sub>2</sub>O<sub>42</sub>}·23H<sub>2</sub>O (<b>2</b>), {CuÂ(en)<sub>2</sub>}<sub>6</sub>{SiNb<sub>12</sub>V<sup>IV</sup><sub>2</sub>O<sub>42</sub>}·18H<sub>2</sub>O (<b>3</b>), and {CuÂ(en)<sub>2</sub>}<sub>3</sub>K<sub>2</sub>Na<sub>4</sub>{SiNb<sub>12</sub>V<sup>IV</sup><sub>2</sub>O<sub>42</sub>}·19H<sub>2</sub>O (<b>4</b>) (en = ethanediamine), composed
of polyoxoanions [TNb<sub>12</sub>O<sub>40</sub>]<sup>16–</sup> (T = Si and Ge) and [CuÂ(en)<sub>2</sub>]<sup>2+</sup> building blocks,
were successfully synthesized under hydrothermal conditions by reaction
of K<sub>7</sub>HNb<sub>6</sub>O<sub>19</sub>·13H<sub>2</sub>O, CuÂ(Ac)<sub>2</sub>·3H<sub>2</sub>O, Na<sub>2</sub>VO<sub>3</sub>, Na<sub>2</sub>SiO<sub>3</sub>, or GeO<sub>2</sub> and en
molecules. Polyoxoanion [TNb<sub>12</sub>VIV<sub>2</sub>O<sub>42</sub>]<sup>12–</sup> (T = Si and Ge) can be best described as a
α-Keggin core [TNb<sub>12</sub>O<sub>40</sub>] with two [VO]
units capping on its two “opened windows”. Compounds <b>1</b> and <b>3</b> are both composed of the bicapped heteropolyoxonibate
core surrounded by a shell consisting of twelve [CuÂ(en)<sub>2</sub>]<sup>2+</sup> groups, which represent a promising structural model
toward core–shell nanostructures. Compounds <b>2</b> and <b>4</b> are also composed of a bicapped polyoxoanion [TNb<sub>12</sub>V<sup>IV</sup><sub>2</sub>O<sub>42</sub>]<sup>12–</sup> (T
= Si, Ge) decorated by three metal–organic fragments [CuÂ(en)<sub>2</sub>]<sup>2+</sup>, forming a trisupporting polyoxoanion {[CuÂ(en)<sub>2</sub>]<sub>3</sub>[TNb<sub>12</sub>O<sub>42</sub>V<sup>IV</sup><sub>2</sub>]}<sup>6–</sup>. Antitumor, electrochemical study,
and UV–vis spectra indicate that compounds <b>1</b>–<b>4</b> exhibit effective antitumor activity against SGC7901 cells
and HepG2 cells and could keep the structural integrity in this process
Four Polyoxonibate-Based Inorganic–Organic Hybrids Assembly from Bicapped Heteropolyoxonibate with Effective Antitumor Activity
Four
novel heteropolyoxonibate-based inorganic–organic hybrids
{CuÂ(en)<sub>2</sub>}<sub>6</sub>{GeNb<sub>12</sub>V<sup>IV</sup><sub>2</sub>O<sub>42</sub>}·20H<sub>2</sub>O (<b>1</b>), {CuÂ(en)<sub>2</sub>}<sub>3</sub>K<sub>2</sub>Na<sub>4</sub>{GeNb<sub>12</sub>V<sup>IV</sup><sub>2</sub>O<sub>42</sub>}·23H<sub>2</sub>O (<b>2</b>), {CuÂ(en)<sub>2</sub>}<sub>6</sub>{SiNb<sub>12</sub>V<sup>IV</sup><sub>2</sub>O<sub>42</sub>}·18H<sub>2</sub>O (<b>3</b>), and {CuÂ(en)<sub>2</sub>}<sub>3</sub>K<sub>2</sub>Na<sub>4</sub>{SiNb<sub>12</sub>V<sup>IV</sup><sub>2</sub>O<sub>42</sub>}·19H<sub>2</sub>O (<b>4</b>) (en = ethanediamine), composed
of polyoxoanions [TNb<sub>12</sub>O<sub>40</sub>]<sup>16–</sup> (T = Si and Ge) and [CuÂ(en)<sub>2</sub>]<sup>2+</sup> building blocks,
were successfully synthesized under hydrothermal conditions by reaction
of K<sub>7</sub>HNb<sub>6</sub>O<sub>19</sub>·13H<sub>2</sub>O, CuÂ(Ac)<sub>2</sub>·3H<sub>2</sub>O, Na<sub>2</sub>VO<sub>3</sub>, Na<sub>2</sub>SiO<sub>3</sub>, or GeO<sub>2</sub> and en
molecules. Polyoxoanion [TNb<sub>12</sub>VIV<sub>2</sub>O<sub>42</sub>]<sup>12–</sup> (T = Si and Ge) can be best described as a
α-Keggin core [TNb<sub>12</sub>O<sub>40</sub>] with two [VO]
units capping on its two “opened windows”. Compounds <b>1</b> and <b>3</b> are both composed of the bicapped heteropolyoxonibate
core surrounded by a shell consisting of twelve [CuÂ(en)<sub>2</sub>]<sup>2+</sup> groups, which represent a promising structural model
toward core–shell nanostructures. Compounds <b>2</b> and <b>4</b> are also composed of a bicapped polyoxoanion [TNb<sub>12</sub>V<sup>IV</sup><sub>2</sub>O<sub>42</sub>]<sup>12–</sup> (T
= Si, Ge) decorated by three metal–organic fragments [CuÂ(en)<sub>2</sub>]<sup>2+</sup>, forming a trisupporting polyoxoanion {[CuÂ(en)<sub>2</sub>]<sub>3</sub>[TNb<sub>12</sub>O<sub>42</sub>V<sup>IV</sup><sub>2</sub>]}<sup>6–</sup>. Antitumor, electrochemical study,
and UV–vis spectra indicate that compounds <b>1</b>–<b>4</b> exhibit effective antitumor activity against SGC7901 cells
and HepG2 cells and could keep the structural integrity in this process
Four Polyoxonibate-Based Inorganic–Organic Hybrids Assembly from Bicapped Heteropolyoxonibate with Effective Antitumor Activity
Four
novel heteropolyoxonibate-based inorganic–organic hybrids
{CuÂ(en)<sub>2</sub>}<sub>6</sub>{GeNb<sub>12</sub>V<sup>IV</sup><sub>2</sub>O<sub>42</sub>}·20H<sub>2</sub>O (<b>1</b>), {CuÂ(en)<sub>2</sub>}<sub>3</sub>K<sub>2</sub>Na<sub>4</sub>{GeNb<sub>12</sub>V<sup>IV</sup><sub>2</sub>O<sub>42</sub>}·23H<sub>2</sub>O (<b>2</b>), {CuÂ(en)<sub>2</sub>}<sub>6</sub>{SiNb<sub>12</sub>V<sup>IV</sup><sub>2</sub>O<sub>42</sub>}·18H<sub>2</sub>O (<b>3</b>), and {CuÂ(en)<sub>2</sub>}<sub>3</sub>K<sub>2</sub>Na<sub>4</sub>{SiNb<sub>12</sub>V<sup>IV</sup><sub>2</sub>O<sub>42</sub>}·19H<sub>2</sub>O (<b>4</b>) (en = ethanediamine), composed
of polyoxoanions [TNb<sub>12</sub>O<sub>40</sub>]<sup>16–</sup> (T = Si and Ge) and [CuÂ(en)<sub>2</sub>]<sup>2+</sup> building blocks,
were successfully synthesized under hydrothermal conditions by reaction
of K<sub>7</sub>HNb<sub>6</sub>O<sub>19</sub>·13H<sub>2</sub>O, CuÂ(Ac)<sub>2</sub>·3H<sub>2</sub>O, Na<sub>2</sub>VO<sub>3</sub>, Na<sub>2</sub>SiO<sub>3</sub>, or GeO<sub>2</sub> and en
molecules. Polyoxoanion [TNb<sub>12</sub>VIV<sub>2</sub>O<sub>42</sub>]<sup>12–</sup> (T = Si and Ge) can be best described as a
α-Keggin core [TNb<sub>12</sub>O<sub>40</sub>] with two [VO]
units capping on its two “opened windows”. Compounds <b>1</b> and <b>3</b> are both composed of the bicapped heteropolyoxonibate
core surrounded by a shell consisting of twelve [CuÂ(en)<sub>2</sub>]<sup>2+</sup> groups, which represent a promising structural model
toward core–shell nanostructures. Compounds <b>2</b> and <b>4</b> are also composed of a bicapped polyoxoanion [TNb<sub>12</sub>V<sup>IV</sup><sub>2</sub>O<sub>42</sub>]<sup>12–</sup> (T
= Si, Ge) decorated by three metal–organic fragments [CuÂ(en)<sub>2</sub>]<sup>2+</sup>, forming a trisupporting polyoxoanion {[CuÂ(en)<sub>2</sub>]<sub>3</sub>[TNb<sub>12</sub>O<sub>42</sub>V<sup>IV</sup><sub>2</sub>]}<sup>6–</sup>. Antitumor, electrochemical study,
and UV–vis spectra indicate that compounds <b>1</b>–<b>4</b> exhibit effective antitumor activity against SGC7901 cells
and HepG2 cells and could keep the structural integrity in this process
Modular and Stepwise Synthesis of a Hybrid Metal–Organic Framework for Efficient Electrocatalytic Oxygen Evolution
The paddle-wheel
type cluster Co<sub>2</sub>Â(RCOO)<sub>4</sub>Â(L<sup>T</sup>)<sub>2</sub> (R = substituent group, L<sup>T</sup> = terminal ligand),
possessing unusual metal coordination geometry
compared with other cobalt compounds, may display high catalytic activity
but is highly unstable especially in water. Here, we show that with
judicious considerations of the host/guest geometries and modular
synthetic strategies, the labile dicobalt clusters can be immobilized
and stabilized in a metal–organic framework (MOF) as coordinative
guests. The FeÂ(na)<sub>4</sub>(L<sup>T</sup>) fragment in the MOF
[{Fe<sub>3</sub>(ÎĽ<sub>3</sub>-O)Â(bdc)<sub>3</sub>}<sub>4</sub>{FeÂ(na)<sub>4</sub>(L<sup>T</sup>)}<sub>3</sub>] (H<sub>2</sub>bdc
= 1,4-benzenedicaboxylic acid, Hna = nicotinic acid) can be removed
to give [{Fe<sub>3</sub>(ÎĽ<sub>3</sub>-O)Â(bdc)<sub>3</sub>}<sub>4</sub>] with a unique framework connectivity possessing suitable
distribution of open metal sites for binding the dicobalt cluster
in the form of Co<sub>2</sub>(na)<sub>4</sub>(L<sup>T</sup>)<sub>2</sub>. After two-step, single-crystal to single-crystal, postsynthetic
modifications, a thermal-, water-, and alkaline-stable MOF [{Fe<sub>3</sub>(ÎĽ<sub>3</sub>-O)Â(bdc)<sub>3</sub>}<sub>4</sub>Â{Co<sub>2</sub>Â(na)<sub>4</sub>Â(L<sup>T</sup>)<sub>2</sub>}<sub>3</sub>] containing the desired dicobalt cluster was obtained, giving
extraordinarily high electrocatalytic oxygen evolution activity in
water at pH = 13 with overpotential as low as 225 mV at 10.0 mA cm<sup>–2</sup>