Four Polyoxonibate-Based Inorganic–Organic Hybrids Assembly from Bicapped Heteropolyoxonibate with Effective Antitumor Activity

Four novel heteropolyoxonibate-based inorganic–organic hybrids {Cu­(en)₂}₆{GeNb₁₂V^IV₂O₄₂}·20H₂O (<b>1</b>), {Cu­(en)₂}₃K₂Na₄{GeNb₁₂V^IV₂O₄₂}·23H₂O (<b>2</b>), {Cu­(en)₂}₆{SiNb₁₂V^IV₂O₄₂}·18H₂O (<b>3</b>), and {Cu­(en)₂}₃K₂Na₄{SiNb₁₂V^IV₂O₄₂}·19H₂O (<b>4</b>) (en = ethanediamine), composed of polyoxoanions [TNb₁₂O₄₀]^16– (T = Si and Ge) and [Cu­(en)₂]²⁺ building blocks, were successfully synthesized under hydrothermal conditions by reaction of K₇HNb₆O₁₉·13H₂O, Cu­(Ac)₂·3H₂O, Na₂VO₃, Na₂SiO₃, or GeO₂ and en molecules. Polyoxoanion [TNb₁₂VIV₂O₄₂]^12– (T = Si and Ge) can be best described as a α-Keggin core [TNb₁₂O₄₀] 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 [Cu­(en)₂]²⁺ 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 [TNb₁₂V^IV₂O₄₂]^12– (T = Si, Ge) decorated by three metal–organic fragments [Cu­(en)₂]²⁺, forming a trisupporting polyoxoanion {[Cu­(en)₂]₃[TNb₁₂O₄₂V^IV₂]}^6–. 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 {Cu­(en)₂}₆{GeNb₁₂V^IV₂O₄₂}·20H₂O (<b>1</b>), {Cu­(en)₂}₃K₂Na₄{GeNb₁₂V^IV₂O₄₂}·23H₂O (<b>2</b>), {Cu­(en)₂}₆{SiNb₁₂V^IV₂O₄₂}·18H₂O (<b>3</b>), and {Cu­(en)₂}₃K₂Na₄{SiNb₁₂V^IV₂O₄₂}·19H₂O (<b>4</b>) (en = ethanediamine), composed of polyoxoanions [TNb₁₂O₄₀]^16– (T = Si and Ge) and [Cu­(en)₂]²⁺ building blocks, were successfully synthesized under hydrothermal conditions by reaction of K₇HNb₆O₁₉·13H₂O, Cu­(Ac)₂·3H₂O, Na₂VO₃, Na₂SiO₃, or GeO₂ and en molecules. Polyoxoanion [TNb₁₂VIV₂O₄₂]^12– (T = Si and Ge) can be best described as a α-Keggin core [TNb₁₂O₄₀] 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 [Cu­(en)₂]²⁺ 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 [TNb₁₂V^IV₂O₄₂]^12– (T = Si, Ge) decorated by three metal–organic fragments [Cu­(en)₂]²⁺, forming a trisupporting polyoxoanion {[Cu­(en)₂]₃[TNb₁₂O₄₂V^IV₂]}^6–. 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 {Cu­(en)₂}₆{GeNb₁₂V^IV₂O₄₂}·20H₂O (<b>1</b>), {Cu­(en)₂}₃K₂Na₄{GeNb₁₂V^IV₂O₄₂}·23H₂O (<b>2</b>), {Cu­(en)₂}₆{SiNb₁₂V^IV₂O₄₂}·18H₂O (<b>3</b>), and {Cu­(en)₂}₃K₂Na₄{SiNb₁₂V^IV₂O₄₂}·19H₂O (<b>4</b>) (en = ethanediamine), composed of polyoxoanions [TNb₁₂O₄₀]^16– (T = Si and Ge) and [Cu­(en)₂]²⁺ building blocks, were successfully synthesized under hydrothermal conditions by reaction of K₇HNb₆O₁₉·13H₂O, Cu­(Ac)₂·3H₂O, Na₂VO₃, Na₂SiO₃, or GeO₂ and en molecules. Polyoxoanion [TNb₁₂VIV₂O₄₂]^12– (T = Si and Ge) can be best described as a α-Keggin core [TNb₁₂O₄₀] 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 [Cu­(en)₂]²⁺ 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 [TNb₁₂V^IV₂O₄₂]^12– (T = Si, Ge) decorated by three metal–organic fragments [Cu­(en)₂]²⁺, forming a trisupporting polyoxoanion {[Cu­(en)₂]₃[TNb₁₂O₄₂V^IV₂]}^6–. 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 CO₂ Reduction

Converting CO₂ 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 CO₂ 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 CO₂ at 1.0 atm, the MOFs bearing μ-OH^– ligands neighboring the open Co centers showed CO selectivities and turnover frequencies (TOFs) up to 98.2% and 0.059 s^–1, respectively. More importantly, their TOFs reduced only ca. 20% when the CO₂ 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^– ligands serve not only as strong hydrogen-bonding donors to stabilize the initial Co–CO₂ 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 {Cu­(en)₂}₆{GeNb₁₂V^IV₂O₄₂}·20H₂O (<b>1</b>), {Cu­(en)₂}₃K₂Na₄{GeNb₁₂V^IV₂O₄₂}·23H₂O (<b>2</b>), {Cu­(en)₂}₆{SiNb₁₂V^IV₂O₄₂}·18H₂O (<b>3</b>), and {Cu­(en)₂}₃K₂Na₄{SiNb₁₂V^IV₂O₄₂}·19H₂O (<b>4</b>) (en = ethanediamine), composed of polyoxoanions [TNb₁₂O₄₀]^16– (T = Si and Ge) and [Cu­(en)₂]²⁺ building blocks, were successfully synthesized under hydrothermal conditions by reaction of K₇HNb₆O₁₉·13H₂O, Cu­(Ac)₂·3H₂O, Na₂VO₃, Na₂SiO₃, or GeO₂ and en molecules. Polyoxoanion [TNb₁₂VIV₂O₄₂]^12– (T = Si and Ge) can be best described as a α-Keggin core [TNb₁₂O₄₀] 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 [Cu­(en)₂]²⁺ 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 [TNb₁₂V^IV₂O₄₂]^12– (T = Si, Ge) decorated by three metal–organic fragments [Cu­(en)₂]²⁺, forming a trisupporting polyoxoanion {[Cu­(en)₂]₃[TNb₁₂O₄₂V^IV₂]}^6–. 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 {Cu­(en)₂}₆{GeNb₁₂V^IV₂O₄₂}·20H₂O (<b>1</b>), {Cu­(en)₂}₃K₂Na₄{GeNb₁₂V^IV₂O₄₂}·23H₂O (<b>2</b>), {Cu­(en)₂}₆{SiNb₁₂V^IV₂O₄₂}·18H₂O (<b>3</b>), and {Cu­(en)₂}₃K₂Na₄{SiNb₁₂V^IV₂O₄₂}·19H₂O (<b>4</b>) (en = ethanediamine), composed of polyoxoanions [TNb₁₂O₄₀]^16– (T = Si and Ge) and [Cu­(en)₂]²⁺ building blocks, were successfully synthesized under hydrothermal conditions by reaction of K₇HNb₆O₁₉·13H₂O, Cu­(Ac)₂·3H₂O, Na₂VO₃, Na₂SiO₃, or GeO₂ and en molecules. Polyoxoanion [TNb₁₂VIV₂O₄₂]^12– (T = Si and Ge) can be best described as a α-Keggin core [TNb₁₂O₄₀] 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 [Cu­(en)₂]²⁺ 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 [TNb₁₂V^IV₂O₄₂]^12– (T = Si, Ge) decorated by three metal–organic fragments [Cu­(en)₂]²⁺, forming a trisupporting polyoxoanion {[Cu­(en)₂]₃[TNb₁₂O₄₂V^IV₂]}^6–. 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 {Cu­(en)₂}₆{GeNb₁₂V^IV₂O₄₂}·20H₂O (<b>1</b>), {Cu­(en)₂}₃K₂Na₄{GeNb₁₂V^IV₂O₄₂}·23H₂O (<b>2</b>), {Cu­(en)₂}₆{SiNb₁₂V^IV₂O₄₂}·18H₂O (<b>3</b>), and {Cu­(en)₂}₃K₂Na₄{SiNb₁₂V^IV₂O₄₂}·19H₂O (<b>4</b>) (en = ethanediamine), composed of polyoxoanions [TNb₁₂O₄₀]^16– (T = Si and Ge) and [Cu­(en)₂]²⁺ building blocks, were successfully synthesized under hydrothermal conditions by reaction of K₇HNb₆O₁₉·13H₂O, Cu­(Ac)₂·3H₂O, Na₂VO₃, Na₂SiO₃, or GeO₂ and en molecules. Polyoxoanion [TNb₁₂VIV₂O₄₂]^12– (T = Si and Ge) can be best described as a α-Keggin core [TNb₁₂O₄₀] 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 [Cu­(en)₂]²⁺ 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 [TNb₁₂V^IV₂O₄₂]^12– (T = Si, Ge) decorated by three metal–organic fragments [Cu­(en)₂]²⁺, forming a trisupporting polyoxoanion {[Cu­(en)₂]₃[TNb₁₂O₄₂V^IV₂]}^6–. 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 {Cu­(en)₂}₆{GeNb₁₂V^IV₂O₄₂}·20H₂O (<b>1</b>), {Cu­(en)₂}₃K₂Na₄{GeNb₁₂V^IV₂O₄₂}·23H₂O (<b>2</b>), {Cu­(en)₂}₆{SiNb₁₂V^IV₂O₄₂}·18H₂O (<b>3</b>), and {Cu­(en)₂}₃K₂Na₄{SiNb₁₂V^IV₂O₄₂}·19H₂O (<b>4</b>) (en = ethanediamine), composed of polyoxoanions [TNb₁₂O₄₀]^16– (T = Si and Ge) and [Cu­(en)₂]²⁺ building blocks, were successfully synthesized under hydrothermal conditions by reaction of K₇HNb₆O₁₉·13H₂O, Cu­(Ac)₂·3H₂O, Na₂VO₃, Na₂SiO₃, or GeO₂ and en molecules. Polyoxoanion [TNb₁₂VIV₂O₄₂]^12– (T = Si and Ge) can be best described as a α-Keggin core [TNb₁₂O₄₀] 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 [Cu­(en)₂]²⁺ 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 [TNb₁₂V^IV₂O₄₂]^12– (T = Si, Ge) decorated by three metal–organic fragments [Cu­(en)₂]²⁺, forming a trisupporting polyoxoanion {[Cu­(en)₂]₃[TNb₁₂O₄₂V^IV₂]}^6–. 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 {Cu­(en)₂}₆{GeNb₁₂V^IV₂O₄₂}·20H₂O (<b>1</b>), {Cu­(en)₂}₃K₂Na₄{GeNb₁₂V^IV₂O₄₂}·23H₂O (<b>2</b>), {Cu­(en)₂}₆{SiNb₁₂V^IV₂O₄₂}·18H₂O (<b>3</b>), and {Cu­(en)₂}₃K₂Na₄{SiNb₁₂V^IV₂O₄₂}·19H₂O (<b>4</b>) (en = ethanediamine), composed of polyoxoanions [TNb₁₂O₄₀]^16– (T = Si and Ge) and [Cu­(en)₂]²⁺ building blocks, were successfully synthesized under hydrothermal conditions by reaction of K₇HNb₆O₁₉·13H₂O, Cu­(Ac)₂·3H₂O, Na₂VO₃, Na₂SiO₃, or GeO₂ and en molecules. Polyoxoanion [TNb₁₂VIV₂O₄₂]^12– (T = Si and Ge) can be best described as a α-Keggin core [TNb₁₂O₄₀] 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 [Cu­(en)₂]²⁺ 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 [TNb₁₂V^IV₂O₄₂]^12– (T = Si, Ge) decorated by three metal–organic fragments [Cu­(en)₂]²⁺, forming a trisupporting polyoxoanion {[Cu­(en)₂]₃[TNb₁₂O₄₂V^IV₂]}^6–. 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 Co₂­(RCOO)₄­(L^T)₂ (R = substituent group, L^T = 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 Fe­(na)₄(L^T) fragment in the MOF [{Fe₃(μ₃-O)­(bdc)₃}₄{Fe­(na)₄(L^T)}₃] (H₂bdc = 1,4-benzenedicaboxylic acid, Hna = nicotinic acid) can be removed to give [{Fe₃(μ₃-O)­(bdc)₃}₄] with a unique framework connectivity possessing suitable distribution of open metal sites for binding the dicobalt cluster in the form of Co₂(na)₄(L^T)₂. After two-step, single-crystal to single-crystal, postsynthetic modifications, a thermal-, water-, and alkaline-stable MOF [{Fe₃(μ₃-O)­(bdc)₃}₄­{Co₂­(na)₄­(L^T)₂}₃] 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^–2