13 research outputs found
Conversion of a Hydrido–Butenylcarbyne Complex to η<sup>2</sup>‑Allene-Coordinated Complexes and Metallabenzenes
Treatment
of OsCl<sub>2</sub>(PPh<sub>3</sub>)<sub>3</sub> with
HCî—¼CCHÂ(OH)ÂEt produces the cyclic complex OsÂ(PPh<sub>3</sub>)<sub>2</sub>Cl<sub>2</sub>(CHCÂ(PPh<sub>3</sub>)ÂCHÂ(OH)ÂCH<sub>2</sub>CH<sub>3</sub>) (<b>1</b>), which can undergo dehydration to
give the hydrido–alkenylvinylidene complex OsÂ(PPh<sub>3</sub>)<sub>2</sub>HCl<sub>2</sub>(î—»Cî—»CÂ(PPh<sub>3</sub>)ÂCHî—»CHCH<sub>3</sub>) (<b>2</b>). Reaction of <b>2</b> with HBF<sub>4</sub> generates the hydrido–butenylcarbyne complex [OsHCl<sub>2</sub>(î—¼CCÂ(PPh<sub>3</sub>)î—»CHÂ(Et))Â(PPh<sub>3</sub>)<sub>2</sub>]ÂBF<sub>4</sub> (<b>3</b>). The complex <b>3</b> evolves into the unstable metallabenzene [(PPh<sub>3</sub>)<sub>2</sub>(RCN)ÂClOsÂ(CHCÂ(PPh<sub>3</sub>)ÂCHCHCH)]ÂBF<sub>4</sub> (<b>4</b>; RCN = benzonitrile, 2-cyanobenzaldehyde, 3-methoxyacrylonitrile,
2-cyanoacetamide) via triple hydrogen eliminations in the presence
of excess nitriles in refluxing CHCl<sub>3</sub> in an air atmosphere.
The ligand substitution reaction of <b>4</b> with excess CO
affords the stable metallabenzene product [(PPh<sub>3</sub>)<sub>2</sub>(CO)ÂClOsÂ(CHCÂ(PPh<sub>3</sub>)ÂCHCHCH)]ÂBF<sub>4</sub> (<b>5</b>). The key intermediates, η<sup>2</sup>-allene-coordinated
osmium complexes [(PPh<sub>3</sub>)<sub>2</sub>(RCN)ÂClOsÂ(CHî—»CÂ(PPh<sub>3</sub>)ÂCHî—»Cî—»CH<sub>2</sub>)]ÂBF<sub>4</sub> (<b>6</b>; RCN = benzonitrile, 2-cyanobenzaldehyde, 3-methoxyacrylonitrile,
2-cyanoacetamide) can be captured by performing the conversion at
room temperature. Remarkably, in the absence of nitriles, reaction
of <b>3</b> with excess CO only generates the vinylethenyl complex
[(PPh<sub>3</sub>)<sub>2</sub>(CO)<sub>2</sub>ClOsÂ(CHî—»CÂ(PPh<sub>3</sub>)ÂCHî—»CHCH<sub>3</sub>)]ÂBF<sub>4</sub> (<b>7</b>). The complexes <b>1</b>–<b>3</b>, <b>5</b>, <b>6a</b>, and <b>7</b> have been structurally characterized
by single-crystal X-ray diffraction. Detailed mechanisms of the conversions
have been investigated with the aid of density functional theory (DFT)
calculations. DFT calculations suggest that the high stablility of
the carbonyl coordinated complexes in the conversion inhibits the
further transformation to metallabenzene product. However, the transformation
is both kinetically and thermodynamically favorable in the presence
of the relatively weaker nitrile ligand, which is consistent with
the experimental conversion of <b>3</b> to <b>5</b> via
unstable metallabenzenes <b>4</b> observed for in situ NMR experiments
Conversion of a Hydrido–Butenylcarbyne Complex to η<sup>2</sup>‑Allene-Coordinated Complexes and Metallabenzenes
Treatment
of OsCl<sub>2</sub>(PPh<sub>3</sub>)<sub>3</sub> with
HCî—¼CCHÂ(OH)ÂEt produces the cyclic complex OsÂ(PPh<sub>3</sub>)<sub>2</sub>Cl<sub>2</sub>(CHCÂ(PPh<sub>3</sub>)ÂCHÂ(OH)ÂCH<sub>2</sub>CH<sub>3</sub>) (<b>1</b>), which can undergo dehydration to
give the hydrido–alkenylvinylidene complex OsÂ(PPh<sub>3</sub>)<sub>2</sub>HCl<sub>2</sub>(î—»Cî—»CÂ(PPh<sub>3</sub>)ÂCHî—»CHCH<sub>3</sub>) (<b>2</b>). Reaction of <b>2</b> with HBF<sub>4</sub> generates the hydrido–butenylcarbyne complex [OsHCl<sub>2</sub>(î—¼CCÂ(PPh<sub>3</sub>)î—»CHÂ(Et))Â(PPh<sub>3</sub>)<sub>2</sub>]ÂBF<sub>4</sub> (<b>3</b>). The complex <b>3</b> evolves into the unstable metallabenzene [(PPh<sub>3</sub>)<sub>2</sub>(RCN)ÂClOsÂ(CHCÂ(PPh<sub>3</sub>)ÂCHCHCH)]ÂBF<sub>4</sub> (<b>4</b>; RCN = benzonitrile, 2-cyanobenzaldehyde, 3-methoxyacrylonitrile,
2-cyanoacetamide) via triple hydrogen eliminations in the presence
of excess nitriles in refluxing CHCl<sub>3</sub> in an air atmosphere.
The ligand substitution reaction of <b>4</b> with excess CO
affords the stable metallabenzene product [(PPh<sub>3</sub>)<sub>2</sub>(CO)ÂClOsÂ(CHCÂ(PPh<sub>3</sub>)ÂCHCHCH)]ÂBF<sub>4</sub> (<b>5</b>). The key intermediates, η<sup>2</sup>-allene-coordinated
osmium complexes [(PPh<sub>3</sub>)<sub>2</sub>(RCN)ÂClOsÂ(CHî—»CÂ(PPh<sub>3</sub>)ÂCHî—»Cî—»CH<sub>2</sub>)]ÂBF<sub>4</sub> (<b>6</b>; RCN = benzonitrile, 2-cyanobenzaldehyde, 3-methoxyacrylonitrile,
2-cyanoacetamide) can be captured by performing the conversion at
room temperature. Remarkably, in the absence of nitriles, reaction
of <b>3</b> with excess CO only generates the vinylethenyl complex
[(PPh<sub>3</sub>)<sub>2</sub>(CO)<sub>2</sub>ClOsÂ(CHî—»CÂ(PPh<sub>3</sub>)ÂCHî—»CHCH<sub>3</sub>)]ÂBF<sub>4</sub> (<b>7</b>). The complexes <b>1</b>–<b>3</b>, <b>5</b>, <b>6a</b>, and <b>7</b> have been structurally characterized
by single-crystal X-ray diffraction. Detailed mechanisms of the conversions
have been investigated with the aid of density functional theory (DFT)
calculations. DFT calculations suggest that the high stablility of
the carbonyl coordinated complexes in the conversion inhibits the
further transformation to metallabenzene product. However, the transformation
is both kinetically and thermodynamically favorable in the presence
of the relatively weaker nitrile ligand, which is consistent with
the experimental conversion of <b>3</b> to <b>5</b> via
unstable metallabenzenes <b>4</b> observed for in situ NMR experiments
Mechanistic Study of Indolizine Heterocycle Formation by Ruthenium(II)-Assisted Three-Component Cross-Coupling<b>/</b>Cyclization
In
the presence of the acid HBF<sub>4</sub>, 3-alkenyl-2-phosphonium
indolizines <b>3a</b>–<b>c</b> can be produced
respectively by adding PhCî—¼CCOCH<sub>3</sub> (<b>2a</b>), CH<sub>3</sub>OCOCî—¼CCOOCH<sub>3</sub> (<b>2b</b>),
and CH<sub>3</sub>CH<sub>2</sub>Cî—¼CCOCH<sub>3</sub> (<b>2c</b>) to a mixture of ruthenium complex RuCl<sub>2</sub>(PPh<sub>3</sub>)<sub>3</sub> and the propargyl alcohol (2-Py)ÂCHÂ(OH)ÂCî—¼CH
(<b>1</b>). We carefully investigated the mechanism of this
reaction by means of structurally characterizing two key intermediates,
ruthenium vinyl (<b>4</b>) and ruthenium carbene (<b>5</b>), and by deuterium-labeling experiments. A plausible mechanism is
proposed, which involves addition of a proton to an alkyne carbon
and the insertion of an alkyne into the Cα bond of an alkenylcarbene
group, followed by an α<i>-</i>H elimination and reductive
elimination
DataSheet_1_Comprehensive resistance evaluation of 15 blueberry cultivars under high soil pH stress based on growth phenotype and physiological traits.docx
High soil pH is one of the main abiotic factors that negatively affects blueberry growth and cultivation. However, no comprehensive evaluation of the high soil pH tolerance of different blueberry cultivars has been conducted. Herein, 16 phenotypic and physiological indices of 15 blueberry cultivars were measured through pot experiments, and the high-pH soil tolerance coefficient (HSTC) was calculated based on these indices to comprehensively evaluate the high-soil-pH tolerance of plants. The results demonstrated that high soil pH stress inhibited blueberry 77.growth, and MDA, soluble sugar (SS), and soluble protein (SP) levels increased in leaves. Moreover, in all cultivars, CAT activity in the antioxidant system was enhanced, whereas SOD activity was reduced, and the relative expression levels of the antioxidant enzyme genes SOD and CAT showed similar changes. In addition, the leaf chlorophyll relative content (SPAD), net photosynthetic rate (Pn), transpiration rate (E), and stomatal conductance (Gs) decreased, while changes in the intercellular CO2 concentration (Ci) were noted in different cultivars. Finally, according to the comprehensive evaluation value D obtained from the combination of principal component analysis (PCA) and membership function (MF), the 15 blueberry cultivars can be divided into 4 categories: high soil pH-tolerant type [‘Briteblue’ (highest D value 0.815)], intermediate tolerance type (‘Zhaixuan 9’, ‘Zhaixuan 7’, ‘Emerald’, ‘Primadonna’, ‘Powderblue’ and ‘Chandler’), low high soil pH-tolerant type (‘Brightwell’, ‘Gardenblue’, ‘Plolific’ and ‘Sharpblue’) and high soil pH-sensitive type [‘Legacy’, ‘Bluegold’, ‘Baldwin’ and ‘Anna’ (lowest D value 0.166)]. Stepwise linear regression analysis revealed that plant height, SS, E, leaf length, Ci, SOD, and SPAD could be used to predict and evaluate the high soil pH tolerance of blueberry cultivars.</p
Conversion of a Hydrido–Butenylcarbyne Complex to η<sup>2</sup>‑Allene-Coordinated Complexes and Metallabenzenes
Treatment
of OsCl<sub>2</sub>(PPh<sub>3</sub>)<sub>3</sub> with
HCî—¼CCHÂ(OH)ÂEt produces the cyclic complex OsÂ(PPh<sub>3</sub>)<sub>2</sub>Cl<sub>2</sub>(CHCÂ(PPh<sub>3</sub>)ÂCHÂ(OH)ÂCH<sub>2</sub>CH<sub>3</sub>) (<b>1</b>), which can undergo dehydration to
give the hydrido–alkenylvinylidene complex OsÂ(PPh<sub>3</sub>)<sub>2</sub>HCl<sub>2</sub>(î—»Cî—»CÂ(PPh<sub>3</sub>)ÂCHî—»CHCH<sub>3</sub>) (<b>2</b>). Reaction of <b>2</b> with HBF<sub>4</sub> generates the hydrido–butenylcarbyne complex [OsHCl<sub>2</sub>(î—¼CCÂ(PPh<sub>3</sub>)î—»CHÂ(Et))Â(PPh<sub>3</sub>)<sub>2</sub>]ÂBF<sub>4</sub> (<b>3</b>). The complex <b>3</b> evolves into the unstable metallabenzene [(PPh<sub>3</sub>)<sub>2</sub>(RCN)ÂClOsÂ(CHCÂ(PPh<sub>3</sub>)ÂCHCHCH)]ÂBF<sub>4</sub> (<b>4</b>; RCN = benzonitrile, 2-cyanobenzaldehyde, 3-methoxyacrylonitrile,
2-cyanoacetamide) via triple hydrogen eliminations in the presence
of excess nitriles in refluxing CHCl<sub>3</sub> in an air atmosphere.
The ligand substitution reaction of <b>4</b> with excess CO
affords the stable metallabenzene product [(PPh<sub>3</sub>)<sub>2</sub>(CO)ÂClOsÂ(CHCÂ(PPh<sub>3</sub>)ÂCHCHCH)]ÂBF<sub>4</sub> (<b>5</b>). The key intermediates, η<sup>2</sup>-allene-coordinated
osmium complexes [(PPh<sub>3</sub>)<sub>2</sub>(RCN)ÂClOsÂ(CHî—»CÂ(PPh<sub>3</sub>)ÂCHî—»Cî—»CH<sub>2</sub>)]ÂBF<sub>4</sub> (<b>6</b>; RCN = benzonitrile, 2-cyanobenzaldehyde, 3-methoxyacrylonitrile,
2-cyanoacetamide) can be captured by performing the conversion at
room temperature. Remarkably, in the absence of nitriles, reaction
of <b>3</b> with excess CO only generates the vinylethenyl complex
[(PPh<sub>3</sub>)<sub>2</sub>(CO)<sub>2</sub>ClOsÂ(CHî—»CÂ(PPh<sub>3</sub>)ÂCHî—»CHCH<sub>3</sub>)]ÂBF<sub>4</sub> (<b>7</b>). The complexes <b>1</b>–<b>3</b>, <b>5</b>, <b>6a</b>, and <b>7</b> have been structurally characterized
by single-crystal X-ray diffraction. Detailed mechanisms of the conversions
have been investigated with the aid of density functional theory (DFT)
calculations. DFT calculations suggest that the high stablility of
the carbonyl coordinated complexes in the conversion inhibits the
further transformation to metallabenzene product. However, the transformation
is both kinetically and thermodynamically favorable in the presence
of the relatively weaker nitrile ligand, which is consistent with
the experimental conversion of <b>3</b> to <b>5</b> via
unstable metallabenzenes <b>4</b> observed for in situ NMR experiments
Conversion of a Hydrido–Butenylcarbyne Complex to η<sup>2</sup>‑Allene-Coordinated Complexes and Metallabenzenes
Treatment
of OsCl<sub>2</sub>(PPh<sub>3</sub>)<sub>3</sub> with
HCî—¼CCHÂ(OH)ÂEt produces the cyclic complex OsÂ(PPh<sub>3</sub>)<sub>2</sub>Cl<sub>2</sub>(CHCÂ(PPh<sub>3</sub>)ÂCHÂ(OH)ÂCH<sub>2</sub>CH<sub>3</sub>) (<b>1</b>), which can undergo dehydration to
give the hydrido–alkenylvinylidene complex OsÂ(PPh<sub>3</sub>)<sub>2</sub>HCl<sub>2</sub>(î—»Cî—»CÂ(PPh<sub>3</sub>)ÂCHî—»CHCH<sub>3</sub>) (<b>2</b>). Reaction of <b>2</b> with HBF<sub>4</sub> generates the hydrido–butenylcarbyne complex [OsHCl<sub>2</sub>(î—¼CCÂ(PPh<sub>3</sub>)î—»CHÂ(Et))Â(PPh<sub>3</sub>)<sub>2</sub>]ÂBF<sub>4</sub> (<b>3</b>). The complex <b>3</b> evolves into the unstable metallabenzene [(PPh<sub>3</sub>)<sub>2</sub>(RCN)ÂClOsÂ(CHCÂ(PPh<sub>3</sub>)ÂCHCHCH)]ÂBF<sub>4</sub> (<b>4</b>; RCN = benzonitrile, 2-cyanobenzaldehyde, 3-methoxyacrylonitrile,
2-cyanoacetamide) via triple hydrogen eliminations in the presence
of excess nitriles in refluxing CHCl<sub>3</sub> in an air atmosphere.
The ligand substitution reaction of <b>4</b> with excess CO
affords the stable metallabenzene product [(PPh<sub>3</sub>)<sub>2</sub>(CO)ÂClOsÂ(CHCÂ(PPh<sub>3</sub>)ÂCHCHCH)]ÂBF<sub>4</sub> (<b>5</b>). The key intermediates, η<sup>2</sup>-allene-coordinated
osmium complexes [(PPh<sub>3</sub>)<sub>2</sub>(RCN)ÂClOsÂ(CHî—»CÂ(PPh<sub>3</sub>)ÂCHî—»Cî—»CH<sub>2</sub>)]ÂBF<sub>4</sub> (<b>6</b>; RCN = benzonitrile, 2-cyanobenzaldehyde, 3-methoxyacrylonitrile,
2-cyanoacetamide) can be captured by performing the conversion at
room temperature. Remarkably, in the absence of nitriles, reaction
of <b>3</b> with excess CO only generates the vinylethenyl complex
[(PPh<sub>3</sub>)<sub>2</sub>(CO)<sub>2</sub>ClOsÂ(CHî—»CÂ(PPh<sub>3</sub>)ÂCHî—»CHCH<sub>3</sub>)]ÂBF<sub>4</sub> (<b>7</b>). The complexes <b>1</b>–<b>3</b>, <b>5</b>, <b>6a</b>, and <b>7</b> have been structurally characterized
by single-crystal X-ray diffraction. Detailed mechanisms of the conversions
have been investigated with the aid of density functional theory (DFT)
calculations. DFT calculations suggest that the high stablility of
the carbonyl coordinated complexes in the conversion inhibits the
further transformation to metallabenzene product. However, the transformation
is both kinetically and thermodynamically favorable in the presence
of the relatively weaker nitrile ligand, which is consistent with
the experimental conversion of <b>3</b> to <b>5</b> via
unstable metallabenzenes <b>4</b> observed for in situ NMR experiments
Conversion of a Hydrido–Butenylcarbyne Complex to η<sup>2</sup>‑Allene-Coordinated Complexes and Metallabenzenes
Treatment
of OsCl<sub>2</sub>(PPh<sub>3</sub>)<sub>3</sub> with
HCî—¼CCHÂ(OH)ÂEt produces the cyclic complex OsÂ(PPh<sub>3</sub>)<sub>2</sub>Cl<sub>2</sub>(CHCÂ(PPh<sub>3</sub>)ÂCHÂ(OH)ÂCH<sub>2</sub>CH<sub>3</sub>) (<b>1</b>), which can undergo dehydration to
give the hydrido–alkenylvinylidene complex OsÂ(PPh<sub>3</sub>)<sub>2</sub>HCl<sub>2</sub>(î—»Cî—»CÂ(PPh<sub>3</sub>)ÂCHî—»CHCH<sub>3</sub>) (<b>2</b>). Reaction of <b>2</b> with HBF<sub>4</sub> generates the hydrido–butenylcarbyne complex [OsHCl<sub>2</sub>(î—¼CCÂ(PPh<sub>3</sub>)î—»CHÂ(Et))Â(PPh<sub>3</sub>)<sub>2</sub>]ÂBF<sub>4</sub> (<b>3</b>). The complex <b>3</b> evolves into the unstable metallabenzene [(PPh<sub>3</sub>)<sub>2</sub>(RCN)ÂClOsÂ(CHCÂ(PPh<sub>3</sub>)ÂCHCHCH)]ÂBF<sub>4</sub> (<b>4</b>; RCN = benzonitrile, 2-cyanobenzaldehyde, 3-methoxyacrylonitrile,
2-cyanoacetamide) via triple hydrogen eliminations in the presence
of excess nitriles in refluxing CHCl<sub>3</sub> in an air atmosphere.
The ligand substitution reaction of <b>4</b> with excess CO
affords the stable metallabenzene product [(PPh<sub>3</sub>)<sub>2</sub>(CO)ÂClOsÂ(CHCÂ(PPh<sub>3</sub>)ÂCHCHCH)]ÂBF<sub>4</sub> (<b>5</b>). The key intermediates, η<sup>2</sup>-allene-coordinated
osmium complexes [(PPh<sub>3</sub>)<sub>2</sub>(RCN)ÂClOsÂ(CHî—»CÂ(PPh<sub>3</sub>)ÂCHî—»Cî—»CH<sub>2</sub>)]ÂBF<sub>4</sub> (<b>6</b>; RCN = benzonitrile, 2-cyanobenzaldehyde, 3-methoxyacrylonitrile,
2-cyanoacetamide) can be captured by performing the conversion at
room temperature. Remarkably, in the absence of nitriles, reaction
of <b>3</b> with excess CO only generates the vinylethenyl complex
[(PPh<sub>3</sub>)<sub>2</sub>(CO)<sub>2</sub>ClOsÂ(CHî—»CÂ(PPh<sub>3</sub>)ÂCHî—»CHCH<sub>3</sub>)]ÂBF<sub>4</sub> (<b>7</b>). The complexes <b>1</b>–<b>3</b>, <b>5</b>, <b>6a</b>, and <b>7</b> have been structurally characterized
by single-crystal X-ray diffraction. Detailed mechanisms of the conversions
have been investigated with the aid of density functional theory (DFT)
calculations. DFT calculations suggest that the high stablility of
the carbonyl coordinated complexes in the conversion inhibits the
further transformation to metallabenzene product. However, the transformation
is both kinetically and thermodynamically favorable in the presence
of the relatively weaker nitrile ligand, which is consistent with
the experimental conversion of <b>3</b> to <b>5</b> via
unstable metallabenzenes <b>4</b> observed for in situ NMR experiments
Conversion of a Hydrido–Butenylcarbyne Complex to η<sup>2</sup>‑Allene-Coordinated Complexes and Metallabenzenes
Treatment
of OsCl<sub>2</sub>(PPh<sub>3</sub>)<sub>3</sub> with
HCî—¼CCHÂ(OH)ÂEt produces the cyclic complex OsÂ(PPh<sub>3</sub>)<sub>2</sub>Cl<sub>2</sub>(CHCÂ(PPh<sub>3</sub>)ÂCHÂ(OH)ÂCH<sub>2</sub>CH<sub>3</sub>) (<b>1</b>), which can undergo dehydration to
give the hydrido–alkenylvinylidene complex OsÂ(PPh<sub>3</sub>)<sub>2</sub>HCl<sub>2</sub>(î—»Cî—»CÂ(PPh<sub>3</sub>)ÂCHî—»CHCH<sub>3</sub>) (<b>2</b>). Reaction of <b>2</b> with HBF<sub>4</sub> generates the hydrido–butenylcarbyne complex [OsHCl<sub>2</sub>(î—¼CCÂ(PPh<sub>3</sub>)î—»CHÂ(Et))Â(PPh<sub>3</sub>)<sub>2</sub>]ÂBF<sub>4</sub> (<b>3</b>). The complex <b>3</b> evolves into the unstable metallabenzene [(PPh<sub>3</sub>)<sub>2</sub>(RCN)ÂClOsÂ(CHCÂ(PPh<sub>3</sub>)ÂCHCHCH)]ÂBF<sub>4</sub> (<b>4</b>; RCN = benzonitrile, 2-cyanobenzaldehyde, 3-methoxyacrylonitrile,
2-cyanoacetamide) via triple hydrogen eliminations in the presence
of excess nitriles in refluxing CHCl<sub>3</sub> in an air atmosphere.
The ligand substitution reaction of <b>4</b> with excess CO
affords the stable metallabenzene product [(PPh<sub>3</sub>)<sub>2</sub>(CO)ÂClOsÂ(CHCÂ(PPh<sub>3</sub>)ÂCHCHCH)]ÂBF<sub>4</sub> (<b>5</b>). The key intermediates, η<sup>2</sup>-allene-coordinated
osmium complexes [(PPh<sub>3</sub>)<sub>2</sub>(RCN)ÂClOsÂ(CHî—»CÂ(PPh<sub>3</sub>)ÂCHî—»Cî—»CH<sub>2</sub>)]ÂBF<sub>4</sub> (<b>6</b>; RCN = benzonitrile, 2-cyanobenzaldehyde, 3-methoxyacrylonitrile,
2-cyanoacetamide) can be captured by performing the conversion at
room temperature. Remarkably, in the absence of nitriles, reaction
of <b>3</b> with excess CO only generates the vinylethenyl complex
[(PPh<sub>3</sub>)<sub>2</sub>(CO)<sub>2</sub>ClOsÂ(CHî—»CÂ(PPh<sub>3</sub>)ÂCHî—»CHCH<sub>3</sub>)]ÂBF<sub>4</sub> (<b>7</b>). The complexes <b>1</b>–<b>3</b>, <b>5</b>, <b>6a</b>, and <b>7</b> have been structurally characterized
by single-crystal X-ray diffraction. Detailed mechanisms of the conversions
have been investigated with the aid of density functional theory (DFT)
calculations. DFT calculations suggest that the high stablility of
the carbonyl coordinated complexes in the conversion inhibits the
further transformation to metallabenzene product. However, the transformation
is both kinetically and thermodynamically favorable in the presence
of the relatively weaker nitrile ligand, which is consistent with
the experimental conversion of <b>3</b> to <b>5</b> via
unstable metallabenzenes <b>4</b> observed for in situ NMR experiments
Synthesis of One-Handed Helical Block Copoly(substituted acetylene)s Consisting of Dynamic <i>cis-transoidal</i> and Static <i>cis-cisoidal</i> Block: Chiral Teleinduction in Helix-Sense-Selective Polymerization Using a Chiral Living Polymer as an Initiator
By using a living
one-handed helical <i>cis-transoidal</i> polyÂ(chiral substituted
phenylacetylene) as a polymer initiator
(polyÂ(<b>1</b><sub>n</sub>)), helix-sense-selective polymerization
(<b>HSSP</b>) of an achiral phenylacetylene <b>2</b> having
two hydroxy groups successfully afforded a diblock copolyÂ(phenylacetylene)
(copolyÂ(<b>1</b><sub>n</sub>/<b>2</b><sub>m</sub>)) consisting
of a dynamic one-handed helical <i>cis-transoidal</i> block
and a static one-handed helical <i>cis-cisoidal</i> block.
The formation of the diblock structure was confirmed by consumption
of the chiral initiator, appearance of characteristic CD indicating
the one-handed helical <i>cis-cisoidal</i> block, and occurrence
of the selective photocylic aromatization reaction in the <i>cis-cisoidal</i> block. Therefore, <b>HSSP</b> has been
achieved by using the chiral alkenyl groups in the initiator as a
chiral source for the first time. In addition, since the <b>HSSP</b> was achieved in spite of the long distance between the chiral initiation
site and the propagating site, chiral teleinduction through the rigid
and static one-handed helical <i>cis</i>-cisoidal block
based on domino effects was confirmed
Exploring the Segregating and Mineralization-Inducing Capacities of Cationic Hydrophilic Polymers for Preparation of Robust, Multifunctional Mesoporous Hybrid Microcapsules
A facile
approach to preparing mesoporous hybrid microcapsules
is developed by exploring the segregating and mineralization-inducing
capacities of cationic hydrophilic polymer. The preparation process
contains four steps: segregation of cationic hydrophilic polymer during
template formation, cross-linking of the segregated polymer, biomimetic
mineralization within cross-linked polymer network, and removal of
template to simultaneously generate capsule lumen and mesopores on
the capsule wall. PolyÂ(allylamine hydrochloride) (PAH) is chosen as
the model polymer, its hydrophilicity renders the segregating capacity
and spontaneous enrichment in the near-surface region of CaCO<sub>3</sub> microspheres; its biopolyamine-mimic structure renders the
mineralization-inducing capacity to produce titania from the water-soluble
titaniumÂ(IV) precursor. Meanwhile, CaCO<sub>3</sub> microspheres serve
the dual templating functions in the formation of hollow lumen and
mesoporous wall. The thickness of capsule wall can be controlled by
changing the polymer segregating and cross-linking conditions, while
the pore size on the capsule wall can be tuned by changing the template
synthesizing conditions. The robust hybrid microcapsules exhibit desirable
efficiency in enzymatic catalysis, wastewater treatment and drug delivery.
This approach may open facile, generic, and efficient pathway to designing
and preparing a variety of hybrid microcapsules with high and tunable
permeability, good stability and multiple functionalities for a broad
range of applications