9 research outputs found
Assembly and Selective Photocatalysis of Two Multifunctional Copper(II) Complexes Derived From a Bis-Pyridyl-Bis-Amide and Two Dicarboxylates
<p>Two multifunctional metal-organic coordination polymers, namely [Cu(4-bpah)(2,6-PDA)] (<b>1</b>) and [Cu(4-bpah)(3-NIP)]·H<sub>2</sub>O (<b>2</b>), where 4-bpah = <i>N, N</i>′-bis(4-pyridinecarboxamide)-1,2-cyclohexane, 2,6-H<sub>2</sub>PDA = pyridine-2,6-dicarboxylic acid, 3-H<sub>2</sub>NIP = 3-nitrophalic acid, have been hydrothermally synthesized and structurally characterized by IR, TG, and single-crystal X-ray diffraction analyses. Complex <b>1</b> is a 1D infinite helix chain structure. Complex <b>2</b> possesses a 2D polymeric layer containing two kinds of <i>meso</i>-helical chains: [Cu-4-bpah]<sub>n</sub> and [Cu-3-NIP]<sub>n</sub>. The adjacent 1D chains for <b>1</b> or the adjacent 2D layers for <b>2</b> are further linked by hydrogen bonding interactions to form 2D or 3D supramolecular networks, respectively. The fluorescent, electrochemical and photocatalytic properties of complexes <b>1–2</b> have also been investigated.</p
An Effective Strategy To Construct Novel Polyoxometalate-Based Hybrids by Deliberately Controlling Organic Ligand Transformation <i>In Situ</i>
Deliberately controlling
organic ligand transformation <i>in situ</i> has remained
a challenge for the construction of
polyoxometalate (POM)-based inorganic–organic hybrids. In this
work, four POM-based hybrids assembled from an <i>in situ</i> bifurcating organic ligandî—¸[Cu<sub>2</sub>(DIBA)<sub>4</sub>]Â(H<sub>3</sub>PMo<sub>12</sub>O<sub>40</sub>)·6H<sub>2</sub>O (<b>1</b>), [Cu<sub>2</sub>(DIBA)<sub>4</sub>]Â(H<sub>4</sub>SiW<sub>12</sub>O<sub>40</sub>)·6H<sub>2</sub>O (<b>2</b>), [AgÂ(HDIBA)<sub>2</sub>]Â(H<sub>2</sub>PMo<sub>12</sub>O<sub>40</sub>)·2H<sub>2</sub>O (<b>3</b>), [Ag<sub>3</sub>(HDIBA)<sub>2</sub>(H<sub>2</sub>O)]Â[(P<sub>2</sub>W<sub>18</sub>O<sub>62</sub>)<sub>1/2</sub>]·4H<sub>2</sub>O (<b>4</b>) (DIBAH = 3,5-diÂ(1H-imidazol-1-yl)
benzoic acid)î—¸have been designed and obtained under hydrothermal
conditions. Compounds <b>1</b> and <b>2</b> are isostructural,
displaying a three-dimensional (3D) 2-fold interpenetrating framework
with two types of channels, and the bigger channels are occupied by
Keggin polyoxoanions and crystallization water molecules, but only
crystallization water molecules in the smaller ones. Compound <b>3</b> displays a 3D supramolecular structure constructed from
{AgÂ(HDIBA)<sub>2</sub>} segments and PMo<sub>12</sub>O<sub>40</sub><sup>3–</sup> polyoxoanions through hydrogen bonding interactions.
Compound <b>4</b> shows a 3D 2-fold interpenetrating framework
based on (3, 3, 4)-connected network, which is constructed from {Ag<sub>3</sub>(HDIBA)<sub>2</sub>}<sub><i>n</i></sub> chains and
P<sub>2</sub>W<sub>18</sub>O<sub>62</sub><sup>6–</sup> polyoxoanions
as linkers. The DIBAH ligand was generated <i>in situ</i> from 3,5-diÂ(1H-imidazol-1-yl)Âbenzonitrile by deliberate design,
which illustrates that the strategy to construct novel POM-based hybrids
by controlling ligand transformation <i>in situ</i> is rational
and feasible. In addition, the effects of the central metal and POMs
on the structures of the target compounds were discussed. Finally,
the electrochemical and photocatalytic properties of compounds <b>1</b>–<b>4</b> have been investigated in this paper
Various Polycarboxylate-Directed Cd(II) Coordination Polymers Based on a Semirigid Bis-pyridyl-bis-amide Ligand: Construction and Fluorescent and Photocatalytic Properties
Nine new CdÂ(II) coordination
polymers (CPs) including [Cd<sub>3</sub>(4-bmbpd)<sub>4</sub>ÂCl<sub>6</sub>(H<sub>2</sub>O)<sub>2</sub>] (<b>1</b>), [CdÂ(4-bmbpd)Â(2,2′-BDC)Â(H<sub>2</sub>O)] (<b>2</b>), [CdÂ(4-bmbpd)Â(OBA)]·H<sub>2</sub>O (<b>3</b>), [CdÂ(4-bmbpd)<sub>0.5</sub>Â(ADTZ)Â(H<sub>2</sub>O)]·H<sub>2</sub>O (<b>4</b>), [Cd<sub>4</sub>(4-bmbpd)Â(1,3-ATDC)<sub>4</sub>Â(H<sub>2</sub>O)<sub>6</sub>]·2H<sub>2</sub>O (<b>5</b>), [CdÂ(4-bmbpd)Â(3-NPH)Â(H<sub>2</sub>O)]·H<sub>2</sub>O (<b>6</b>), [CdÂ(4-bmbpd)<sub>0.5</sub>Â(NIP)Â(H<sub>2</sub>O)] (<b>7</b>), [CdÂ(4-bmbpd)<sub>0.5</sub>Â(HIP)]·H<sub>2</sub>O (<b>8</b>),
and [Cd<sub>3</sub>(4-bmbpd)<sub>2</sub>Â(1,3,5-BTC)Â(H<sub>2</sub>O)<sub>4</sub>]·4H<sub>2</sub>O (<b>9</b>) (4-bmbpd = <i>N</i>,<i>N</i>′-bisÂ(4-methylenepyridin-4-yl)-1,4-benzenedicarboxamide,
2,2′-H<sub>2</sub>BDC = 2,2′-biphenyldicarboxylic acid,
H<sub>2</sub>OBA = 4,4′-oxybisÂ(benzoic acid, H<sub>2</sub>ADTZ
= 2,5-(s-acetic acid)Âdimercapto-1,3,4-thiadiazole, 1,3-H<sub>2</sub>ATDC = 1,3-adamantanedicarboxylic acid, 3-H<sub>2</sub>NPH = 3-nitrophthalic
acid, H<sub>2</sub>NIP = 5-nitroisophthalic acid, H<sub>2</sub>HIP
= 5-hydroxyisophthalic acid, and 1,3,5- H<sub>3</sub>BTC = 1,3,5-benzenetricarboxylic
acid), have been produced with a hydrothermal/solvothermal technique
and structurally characterized by single-crystal X-ray diffraction,
powder X-ray diffraction, thermogravimetric analysis, and infrared
spectroscopy. Complex <b>1</b> exhibits a one-dimensional (1D)
wave-like double chain constructed from [Cd<sub>3</sub>(4-bmbpd)<sub>2</sub>ÂCl<sub>6</sub>(H<sub>2</sub>O)<sub>2</sub>] subunits
and μ<sub>2</sub>-bridging 4-bmbpd ligands. <b>2</b> is
a two-dimensional (2D) 4-connected layer consisting of 1D [Cd-4-bmbpd]<sub><i>n</i></sub> zigzag chains and 1D [Cd-2,2′-BDC]<sub><i>n</i></sub> single-strand helix chains. Complex <b>3</b> is also a 2D 4-connected network constituted of 1D [Cd-OBA]<sub><i>n</i></sub> linear chains and [CdÂ(4-bmbpd)]<sub><i>n</i></sub> wave-like chains. Complex <b>4</b> has a (2,4,4)-connected
2D architecture based on [Cd<sub>2</sub>(ADTZ)<sub>2</sub>] rings
and μ<sub>4</sub>-bridging 4-bmbpd ligands with {4<sup>2</sup>·8<sup>2</sup>·10<sup>2</sup>}Â{ 4<sup>2</sup>·8<sup>4</sup>}<sub>2</sub>{4}<sub>2</sub> topology. Complex <b>5</b> exhibits an intriguing 1D chain constructed from [Cd<sub>4</sub>(1,3-ATDC)<sub>4</sub>] rings and μ<sub>2</sub>/μ<sub>4</sub>-bridging 4-bmbpd ligands. Complex <b>6</b> presents
a 1D ladder-shaped chain. Complex <b>7</b> displays a 3D (4,4)-connected
framework giving an interesting self-penetrating structure. Complex <b>8</b> is a 3D (4,5)-connected architecture with {4<sup>4</sup>·6<sup>2</sup>}Â{4<sup>4</sup>·6<sup>6</sup>} topology. <b>9</b> shows a 3D (2,3,4,4)-connected framework, which contains
[Cd-1,3,5-BTC]<sub><i>n</i></sub> 1D double chains. The
versatile structures reveal the impact of the carboxyl position and
number, the flexibility, as well as the functional groups of polycarboxylate
auxiliary ligands on the architectures. Furthermore, the effects of
different organic solvents on the fluorescent behaviors of <b>1</b>–<b>4</b> and <b>7</b>–<b>9</b>,
and the photocatalytic properties of <b>1</b>–<b>9</b> under UV irradiation, were studied
Structural Diversities and Fluorescent and Photocatalytic Properties of a Series of Cu<sup>II</sup> Coordination Polymers Constructed from Flexible Bis-pyridyl-bis-amide Ligands with Different Spacer Lengths and Different Aromatic Carboxylates
Thirteen
new Cu<sup>II</sup> coordination polymers, namely, [CuÂ(3-dppa)Â(1,3,5-HBTC)]
(<b>1</b>), [CuÂ(3-dpha)Â(1,3,5-HBTC)Â(H<sub>2</sub>O)]·H<sub>2</sub>O (<b>2</b>), [Cu<sub>3</sub>(3-dpsea)Â(1,3,5-BTC)<sub>2</sub>Â(H<sub>2</sub>O)<sub>5</sub>]·4H<sub>2</sub>O (<b>3</b>), [CuÂ(3-dpba)Â(1,2-BDC)]·H<sub>2</sub>O
(<b>4</b>), [CuÂ(3-dpha)Â(1,2-BDC)] (<b>5</b>), [CuÂ(3-dpsea)Â(1,2-BDC)]·H<sub>2</sub>O (<b>6</b>), [Cu<sub>2</sub>(3-dpyp)Â(1,3-BDC)<sub>2</sub>Â(H<sub>2</sub>O)<sub>4</sub>]·3H<sub>2</sub>O (<b>7</b>), [CuÂ(3-dppa)Â(1,3-BDC)Â(H<sub>2</sub>O)]·2H<sub>2</sub>O (<b>8</b>), [CuÂ(3-dppia)Â(1,3-BDC)Â(H<sub>2</sub>O)<sub>2</sub>]·2H<sub>2</sub>O (<b>9</b>), [Cu<sub>2</sub>(3-dpsea)<sub>2</sub>Â(1,3-BDC)<sub>2</sub>Â(H<sub>2</sub>O)<sub>2</sub>]·7H<sub>2</sub>O (<b>10</b>), [CuÂ(3-dpba)Â(1,4-NDC)]·3H<sub>2</sub>O (<b>11</b>), [CuÂ(3-dpyh)Â(1,4-NDC)Â(H<sub>2</sub>O)]·3H<sub>2</sub>O (<b>12</b>), [CuÂ(3-dpyh)<sub>0.5</sub>Â(1,4-NDC)]·H<sub>2</sub>O (<b>13</b>), have been purposefully synthesized under hydrothermal conditions
[3-dppa = <i>N</i>,<i>N</i>′-diÂ(3-pyridyl)Âpropanediamide,
3-dpba = <i>N</i>,<i>N</i>′-diÂ(3-pyridyl)Âbutanediamide,
3-dpha = <i>N</i>,<i>N</i>′-diÂ(3-pyridyl)Âhexanedioicdiamide,
3-dppia = <i>N</i>,<i>N</i>′-diÂ(3-pyridyl)Âpimelicdiamide,
3-dpsea = <i>N</i>,<i>N</i>′-diÂ(3-pyridyl)Âsebacicdiamide,
3-dpyp = <i>N</i>,<i>N</i>′-diÂ(3-pyridineÂcarboxamide)-1,3-propane,
3-dpyh = <i>N</i>,<i>N</i>′-diÂ(3-pyridineÂcarboxamide)-1,6-hexane,
1,3,5-H<sub>3</sub>BTC = 1,3,5-benzenetricarboxylic acid, 1,2-H<sub>2</sub>BDC = 1,2-benzenedicarboxylic acid, 1,3-H<sub>2</sub>BDC =
1,3-benzenedicarboxylic acid and 1,4-H<sub>2</sub>NDC = 1,4-naphthalenedicarboxylic
acid]. Complexes <b>1</b>–<b>3</b> based on the
same auxiliary ligand show various structures. Complex <b>1</b> features a one-dimensional (1D) ∞-like double-chain structure,
which consists of a [Cu-1,3,5-HBTC]<sub><i>n</i></sub> chain
and [Cu-3-dppa]<sub><i>n</i></sub> <i>meso</i>-helical chain. Complex <b>2</b> possesses a (2,4) undulated
honeycomb (hcb) net. Complex <b>3</b> is a 3-fold interpenetrating
three-dimensional (3D) framework, which shows trinodal (2,3,3)-connected
topology with the Schläfli symbol of (10·12<sup>2</sup>)<sub>2</sub>(10<sup>3</sup>)<sub>2</sub>(12). Complexes <b>4</b>–<b>6</b> with 1,2-BDC as secondary ligand exhibit different
two-dimensional (2D) layer structures. Complex <b>4</b> exhibits
a 2D (2,4)-connected (4·12<sup>4</sup>·14)Â(4) net. Complexes <b>5</b> and <b>6</b> have similar structures and show 2D networks
with undulated sql topology. For complexes <b>7</b>–<b>10</b> based on 1,3-BDC secondary ligand, complex <b>7</b> shows a 1D zigzag chain, while complexes <b>8</b>–<b>10</b> have similar wave-like 2D structures. When 1,4-NDC was
used as the auxiliary ligand, complex <b>11</b> is a 2D puckered
(4,4) network, complex <b>12</b> reveals a 4-connected topology
with the point symbol of (4<sup>4</sup>·6<sup>2</sup>), while
complex <b>13</b> exhibits a 3-fold interpenetrating 3D α-Po
framework. The structural diversity indicates that the bis-pyridyl-bis-amide
ligands with different spacers and the aromatic polycarboxylates play
important roles in tuning the dimensionalities and structures of the
title complexes. The fluorescent and photocatalytic properties for <b>1</b>–<b>13</b> have also been investigated in detail
Structural Diversities and Fluorescent and Photocatalytic Properties of a Series of Cu<sup>II</sup> Coordination Polymers Constructed from Flexible Bis-pyridyl-bis-amide Ligands with Different Spacer Lengths and Different Aromatic Carboxylates
Thirteen
new Cu<sup>II</sup> coordination polymers, namely, [CuÂ(3-dppa)Â(1,3,5-HBTC)]
(<b>1</b>), [CuÂ(3-dpha)Â(1,3,5-HBTC)Â(H<sub>2</sub>O)]·H<sub>2</sub>O (<b>2</b>), [Cu<sub>3</sub>(3-dpsea)Â(1,3,5-BTC)<sub>2</sub>Â(H<sub>2</sub>O)<sub>5</sub>]·4H<sub>2</sub>O (<b>3</b>), [CuÂ(3-dpba)Â(1,2-BDC)]·H<sub>2</sub>O
(<b>4</b>), [CuÂ(3-dpha)Â(1,2-BDC)] (<b>5</b>), [CuÂ(3-dpsea)Â(1,2-BDC)]·H<sub>2</sub>O (<b>6</b>), [Cu<sub>2</sub>(3-dpyp)Â(1,3-BDC)<sub>2</sub>Â(H<sub>2</sub>O)<sub>4</sub>]·3H<sub>2</sub>O (<b>7</b>), [CuÂ(3-dppa)Â(1,3-BDC)Â(H<sub>2</sub>O)]·2H<sub>2</sub>O (<b>8</b>), [CuÂ(3-dppia)Â(1,3-BDC)Â(H<sub>2</sub>O)<sub>2</sub>]·2H<sub>2</sub>O (<b>9</b>), [Cu<sub>2</sub>(3-dpsea)<sub>2</sub>Â(1,3-BDC)<sub>2</sub>Â(H<sub>2</sub>O)<sub>2</sub>]·7H<sub>2</sub>O (<b>10</b>), [CuÂ(3-dpba)Â(1,4-NDC)]·3H<sub>2</sub>O (<b>11</b>), [CuÂ(3-dpyh)Â(1,4-NDC)Â(H<sub>2</sub>O)]·3H<sub>2</sub>O (<b>12</b>), [CuÂ(3-dpyh)<sub>0.5</sub>Â(1,4-NDC)]·H<sub>2</sub>O (<b>13</b>), have been purposefully synthesized under hydrothermal conditions
[3-dppa = <i>N</i>,<i>N</i>′-diÂ(3-pyridyl)Âpropanediamide,
3-dpba = <i>N</i>,<i>N</i>′-diÂ(3-pyridyl)Âbutanediamide,
3-dpha = <i>N</i>,<i>N</i>′-diÂ(3-pyridyl)Âhexanedioicdiamide,
3-dppia = <i>N</i>,<i>N</i>′-diÂ(3-pyridyl)Âpimelicdiamide,
3-dpsea = <i>N</i>,<i>N</i>′-diÂ(3-pyridyl)Âsebacicdiamide,
3-dpyp = <i>N</i>,<i>N</i>′-diÂ(3-pyridineÂcarboxamide)-1,3-propane,
3-dpyh = <i>N</i>,<i>N</i>′-diÂ(3-pyridineÂcarboxamide)-1,6-hexane,
1,3,5-H<sub>3</sub>BTC = 1,3,5-benzenetricarboxylic acid, 1,2-H<sub>2</sub>BDC = 1,2-benzenedicarboxylic acid, 1,3-H<sub>2</sub>BDC =
1,3-benzenedicarboxylic acid and 1,4-H<sub>2</sub>NDC = 1,4-naphthalenedicarboxylic
acid]. Complexes <b>1</b>–<b>3</b> based on the
same auxiliary ligand show various structures. Complex <b>1</b> features a one-dimensional (1D) ∞-like double-chain structure,
which consists of a [Cu-1,3,5-HBTC]<sub><i>n</i></sub> chain
and [Cu-3-dppa]<sub><i>n</i></sub> <i>meso</i>-helical chain. Complex <b>2</b> possesses a (2,4) undulated
honeycomb (hcb) net. Complex <b>3</b> is a 3-fold interpenetrating
three-dimensional (3D) framework, which shows trinodal (2,3,3)-connected
topology with the Schläfli symbol of (10·12<sup>2</sup>)<sub>2</sub>(10<sup>3</sup>)<sub>2</sub>(12). Complexes <b>4</b>–<b>6</b> with 1,2-BDC as secondary ligand exhibit different
two-dimensional (2D) layer structures. Complex <b>4</b> exhibits
a 2D (2,4)-connected (4·12<sup>4</sup>·14)Â(4) net. Complexes <b>5</b> and <b>6</b> have similar structures and show 2D networks
with undulated sql topology. For complexes <b>7</b>–<b>10</b> based on 1,3-BDC secondary ligand, complex <b>7</b> shows a 1D zigzag chain, while complexes <b>8</b>–<b>10</b> have similar wave-like 2D structures. When 1,4-NDC was
used as the auxiliary ligand, complex <b>11</b> is a 2D puckered
(4,4) network, complex <b>12</b> reveals a 4-connected topology
with the point symbol of (4<sup>4</sup>·6<sup>2</sup>), while
complex <b>13</b> exhibits a 3-fold interpenetrating 3D α-Po
framework. The structural diversity indicates that the bis-pyridyl-bis-amide
ligands with different spacers and the aromatic polycarboxylates play
important roles in tuning the dimensionalities and structures of the
title complexes. The fluorescent and photocatalytic properties for <b>1</b>–<b>13</b> have also been investigated in detail
Spacers-directed structural diversity of Co(II)/Zn(II) complexes based on S-/O-bridged dipyridylamides: electrochemical, fluorescent recognition behavior and photocatalytic properties
<p>To investigate the effect of the spacers of S-/O-bridged dipyridylamides on the structures of Co(II)/Zn(II) complexes, [Co(L<sup>1</sup>)(chda)]·1.5H<sub>2</sub>O (<b>CP1</b>), [Co(L<sup>2</sup>)(chda)] (<b>CP2</b>), [Zn(L<sup>1</sup>)(hip)]·DMA·2H<sub>2</sub>O (<b>CP3</b>), and [Zn(L<sup>2</sup>)(hip)]·2.8H<sub>2</sub>O (<b>CP4</b>) [L<sup>1</sup> = <i>N,N′</i>-bis(pyridine-3-yl)thiophene-2,5-dicarboxamide, H<sub>2</sub>chda = <i>trans</i>-1,4-cyclohexanedicarboxylic acid, L<sup>2</sup> = <i>N,N′</i>-bis(pyridine-3-yl)-4,4′-oxybis(benzoic) dicarboxamide, H<sub>2</sub>hi<i>p</i> = 5-hydroxyisophthalic acid, DMA = <i>N,N</i>-dimethylacetamide], have been solvothermally synthesized. X-ray single-crystal diffraction shows that <b>CP1</b> is a 2-D 3,5-connected network based on Co-L<sup>1</sup> linear chains and (Co-chda)<sub>2</sub> double chains. <b>CP2</b> features a 1-D structure derived from 1-D wave-like (Co-chda)<sub>2</sub> double chains decorated by terminal L<sup>2</sup> ligands. <b>CP3</b> and <b>CP4</b> show wave-like (4,4) networks constructed by 1-D Zn-L<sup>1</sup> zigzag and Zn-hip zigzag (for <b>CP3</b>)/linear (for <b>CP4</b>) chains. The effect of the spacers of S-/O-bridged dipyridylamides on the structures of the title complexes was discussed. Electrochemical behaviors of <b>CP1</b>–<b>CP2</b> and solid-state luminescent properties of <b>CP3</b>–<b>CP4</b> were studied. The luminescence investigations show that <b>CP3</b> and <b>CP4</b> are recycled fluorescent probes for environmentally relevant Fe<sup>3+</sup> ions. The photocatalytic properties for the degradation of methylene blue (MB) under ultraviolet light irradiation of <b>CP3</b>–<b>CP4</b> and the recyclable materials after fluorescent sensing Fe<sup>3+</sup> ions (named <b>CP3</b>@Fe<sup>3+</sup> and <b>CP4</b>@Fe<sup>3+</sup>) have also been investigated.</p
Discovery of Subnanomolar Inhibitors of 4‑Hydroxyphenylpyruvate Dioxygenase via Structure-Based Rational Design
High-potency 4-hydroxyphenylpyruvate dioxygenase (HPPD)
inhibitors
are usually featured by time-dependent inhibition. However, the molecular
mechanism underlying time-dependent inhibition by HPPD inhibitors
has not been fully elucidated. Here, based on the determination of
the HPPD binding mode of natural products, the π–π
sandwich stacking interaction was found to be a critical element determining
time-dependent inhibition. This result implied that, for the time-dependent
inhibitors, strengthening the π–π sandwich stacking
interaction might improve their inhibitory efficacy. Consequently,
modification with one methyl group on the bicyclic ring of quinazolindione
inhibitors was achieved, thereby strengthening the stacking interaction
and significantly improving the inhibitory efficacy. Further introduction
of bulkier hydrophobic substituents with higher flexibility resulted
in a series of HPPD inhibitors with outstanding subnanomolar potency.
Exploration of the time-dependent inhibition mechanism and molecular
design based on the exploration results are very successful cases
of structure-based rational design and provide a guiding reference
for future development of HPPD inhibitors
An Efficient One-Pot Synthesis of 2‑(Aryloxyacetyl)cyclohexane-1,3-diones as Herbicidal 4‑Hydroxyphenylpyruvate Dioxygenase Inhibitors
4-Hydroxyphenylpyruvate dioxygenase
(EC 1.13.11.27, HPPD) is an
important target for new bleaching herbicides discovery. As a continuous
work to discover novel crop selective HPPD inhibitor, a series of
2-(aryloxyacetyl)Âcyclohexane-1,3-diones were rationally designed and
synthesized by an efficient one-pot procedure using <i>N</i>,<i>N</i>′-carbonyldiimidazole (CDI), triethylamine,
and acetone cyanohydrin in CH<sub>2</sub>Cl<sub>2</sub>. A total of
58 triketone compounds were synthesized in good to excellent yields.
Some of the triketones displayed potent in vitro Arabidopsis
thaliana HPPD (<i>At</i>HPPD) inhibitory
activity. 2-(2-((1-Bromonaphthalen-2-yl)Âoxy)Âacetyl)-3-hydroxycyclohex-2-en-1-one, <b>II-13</b>, displayed high, broad-spectrum, and postemergent herbicidal
activity at the dosage of 37.5–150 g ai/ha, nearly as potent
as mesotrione against some weeds. Furthermore, <b>II-13</b> showed
good crop safety against maize and canola at the rate of 150 g ai/ha,
indicating that <b>II-13</b> might have potential as a herbicide
for weed control in maize and canola fields. <b>II-13</b> is
the first HPPD inhibitor showing good crop safety toward canola
Synthesis and Herbicidal Activity of Triketone–Quinoline Hybrids as Novel 4‑Hydroxyphenylpyruvate Dioxygenase Inhibitors
4-Hydroxyphenylpyruvate dioxygenase
(EC 1.13.11.27, HPPD) is one
of the most important targets for herbicide discovery. In the search
for new HPPD inhibitors with novel scaffolds, triketone–quinoline
hybrids were designed and subsequently optimized on the basis of the
structure–activity relationship (SAR) studies. Most of the
synthesized compounds displayed potent inhibition of Arabidopsis thaliana HPPD (<i>At</i>HPPD),
and some of them exhibited broad-spectrum and promising herbicidal
activity at the rate of 150 g ai/ha by postemergence application.
Most promisingly, compound <b>III-l</b>, 3-hydroxy-2-(2-methoxy-7-(methylthio)Âquinoline-3-carbonyl)Âcyclohex-2-enone
(<i>K</i><sub>i</sub> = 0.009 μM, <i>At</i>HPPD), had broader spectrum of weed control than mesotrione. Furthermore,
compound <b>III-l</b> was much safer to maize at the rate of
150 g ai/ha than mesotrione, demonstrating its great potential as
herbicide for weed control in maize fields. Therefore, triketone–quinoline
hybrids may serve as new lead structures for novel herbicide discovery