6 research outputs found
Synthesis, Characterization, and Photophysical Properties of Heteroleptic Copper(I) Complexes with Functionalized 3‑(2′-Pyridyl)-1,2,4-triazole Chelating Ligands
A new
series of mononuclear copperÂ(I) complexes (<b>1</b>–<b>9</b>) with functionalized 3-(2′-pyridyl)-1,2,4-triazole
chelating ligands, as well as the halide and/or phosphine ancillary
ligands, have been synthesized. Complexes <b>1</b>–<b>9</b> were fully characterized by elemental analysis, NMR spectroscopy,
mass spectroscopy, electronic absorption spectroscopy, fluorescence
spectroscopy, cyclic voltammetry, and X-ray crystallography (<b>1</b>–<b>8</b>). They adopt a distorted tetrahedral
configuration, and are considerably air-stable in solid state and
in solution. All these CuÂ(I) complexes display a comparatively weak
low-energy absorption in CH<sub>2</sub>Cl<sub>2</sub> solution, assigned
to charge-transfer transitions with appreciable MLCT character, as
supported by TD-DFT studies. CuÂ(I) halide complexes <b>1</b>–<b>4</b> each shows bright solid-state emission at
room temperature, although they are nonemissive in fluid solutions,
in which the emission markedly depends on the halide and the substituent
on the 2-pyridyl ring. Complexes <b>5</b>–<b>9</b> bearing 2-pyridyl functionalized 1,2,4-triazole and phosphine exhibit
good photoluminescence properties in solution and solid states at
ambient temperature, which are well-modulated via the alteration of
the auxiliary phosphine ligand and the structural modification of
3-(2′-pyridyl)-1,2,4-triazole. Interestingly, cationic complex <b>6</b> and neutral derivative <b>7</b> can readily be interconverted
through the ring inversion of the 1,2,4-triazolyl regulated by the
NH ↔ N<sup>–</sup> transformation
Synthesis and characterization of emissive mononuclear Cu(I) complexes with 5-<i>tert</i>-butyl-3-(pyrimidine-2-yl)-1<i>H</i>-1,2,4-triazole
<div><p>A new series of mononuclear copper(I) halide complexes possessing 5-<i>tert</i>-butyl-3-(pyrimidine-2-yl)-1<i>H</i>-1,2,4-triazole (bpmtzH) and PPh<sub>3</sub>, Cu(bpmtzH)(PPh<sub>3</sub>)X (X = I (<b>1</b>); Br (<b>2</b>); Cl (<b>3</b>)), have been synthesized and characterized. As revealed via X-ray crystallography, <b>1–3</b> show a chiral, distorted tetrahedral N<sub>2</sub>PX arrangement, in which bpmtzH is a neutral bidentate chelating ligand using the 4-N of the 1,2,4-triazolyl ring and one N donor from the 2-pyrimidyl ring, consistent with the computational results. A comparatively weak low-energy absorption tail is observed between 320 and 450 nm for CH<sub>2</sub>Cl<sub>2</sub> solutions of <b>1–3</b> at room temperature, ascribing to charge-transfer transitions with appreciable metal-to-ligand charge transfer (MLCT) character. Complexes <b>1–3</b> in the solid state have good luminescence at ambient temperature, although they are non-emissive in solution. The solid-state emission, most likely originating from both <sup>3</sup>MLCT and <sup>3</sup>XLCT transitions, can be modulated via alteration of the halide bound to {Cu(bpmtzH)(PPh<sub>3</sub>)} motif.</p></div
Luminescent Three- and Four-Coordinate Dinuclear Copper(I) Complexes Triply Bridged by Bis(diphenylphosphino)methane and Functionalized 3‑(2′-Pyridyl)-1,2,4-triazole Ligands
A new series of bimetallic CuÂ(I)
complexes <b>1</b>–<b>5</b> triply bridged by a
monoanionic or charge-neutral functionalized 3-(2′-pyridyl)-1,2,4-triazole
in a μ–η<sup>1</sup>(N),η<sup>2</sup>(N,N)
tridentate binding mode and two bisÂ(diphenylphosphino)Âmethane (dppm)
ligands have been synthesized. Complexes <b>1</b>–<b>5</b> are singly or doubly charged dinuclear CuÂ(I) species with
an eight-membered Cu<sub>2</sub>C<sub>2</sub>P<sub>4</sub> ring of
{CuÂ(μ-dppm)<sub>2</sub>Cu} unit, in which <b>3</b> and <b>4</b> adopt the boat–boat conformation, while <b>1</b>, <b>2</b>, and <b>5</b> display the chair–boat
form. In these dimeric copperÂ(I) complex cations, one of the two CuÂ(I)
ions is four-coordinated, in a highly distorted N<sub>2</sub>P<sub>2</sub> tetrahedral environment and the other is three-coordinated,
in a distorted NP<sub>2</sub> trigonal planar arrangement. All these
CuÂ(I) complexes exhibit a comparatively weak low-energy absorption
in CH<sub>2</sub>Cl<sub>2</sub> solution, ascribed to the charge-transfer
transitions with appreciable <sup>1</sup>MLCT contribution, as suggested
by time-dependent density functional theory (TDDFT) analyses. Complexes <b>1</b>–<b>5</b> display good emission properties in
both solution and solid states at ambient temperature, which are well-modulated
via structural modification of 3-(2′-pyridyl)-1,2,4-triazole,
including the alteration of the substituent type (−CF<sub>3</sub>, −H, −CH<sub>3</sub>, and −CÂ(CH<sub>3</sub>)<sub>3</sub>) and position (<i>ortho</i>-, <i>meta</i>-, and <i>para</i>-position). Furthermore, the variation
of the substituent (−CF<sub>3</sub> and −CÂ(CH<sub>3</sub>)<sub>3</sub>) on the 5-site of the 1,2,4-triazolyl ring markedly
influences the proton activity of the 1,2,4-triazolyl-NH, thus leading
to the formation of both singly and doubly charged bimetallic CuÂ(I)
species regulated by the NH ↔ N<sup>–</sup> conversion, resulting from NH deprotonation of the 1,2,4-triazolyl
ring
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<p>Streptococcus agalactiae and Candida albicans often co-colonize the female genital tract, and under certain conditions induce mucosal inflammation. The role of the interaction between the two organisms in candidal vaginitis is not known. In this study, we found that co-infection with S. agalactiae significantly attenuated the hyphal development of C. albicans, and that EFG1-Hwp1 signal pathway of C. albicans was involved in this process. In a mouse model of vulvovaginal candidiasis (VVC), the fungal burden and the levels of pro-inflammatory cytokines, IL-1β, IL-6 and TNF-α showed a increase on co-infection with S. agalactiae, while the level of TH17 T cells and IL-17 in the cervicovaginal lavage fluid were significantly decreased. Our results indicate that S. agalactiae inhibits C. albicans hyphal development by downregulating the expression of EFG1-Hwp1. The interaction between S. agalactiae and C. albicans may attenuate host vaginal mucosal TH17 immunity and contribute to mucosal colonization by C. albicans.</p
Image_1.tif
<p>Streptococcus agalactiae and Candida albicans often co-colonize the female genital tract, and under certain conditions induce mucosal inflammation. The role of the interaction between the two organisms in candidal vaginitis is not known. In this study, we found that co-infection with S. agalactiae significantly attenuated the hyphal development of C. albicans, and that EFG1-Hwp1 signal pathway of C. albicans was involved in this process. In a mouse model of vulvovaginal candidiasis (VVC), the fungal burden and the levels of pro-inflammatory cytokines, IL-1β, IL-6 and TNF-α showed a increase on co-infection with S. agalactiae, while the level of TH17 T cells and IL-17 in the cervicovaginal lavage fluid were significantly decreased. Our results indicate that S. agalactiae inhibits C. albicans hyphal development by downregulating the expression of EFG1-Hwp1. The interaction between S. agalactiae and C. albicans may attenuate host vaginal mucosal TH17 immunity and contribute to mucosal colonization by C. albicans.</p
Image_2.tif
<p>Streptococcus agalactiae and Candida albicans often co-colonize the female genital tract, and under certain conditions induce mucosal inflammation. The role of the interaction between the two organisms in candidal vaginitis is not known. In this study, we found that co-infection with S. agalactiae significantly attenuated the hyphal development of C. albicans, and that EFG1-Hwp1 signal pathway of C. albicans was involved in this process. In a mouse model of vulvovaginal candidiasis (VVC), the fungal burden and the levels of pro-inflammatory cytokines, IL-1β, IL-6 and TNF-α showed a increase on co-infection with S. agalactiae, while the level of TH17 T cells and IL-17 in the cervicovaginal lavage fluid were significantly decreased. Our results indicate that S. agalactiae inhibits C. albicans hyphal development by downregulating the expression of EFG1-Hwp1. The interaction between S. agalactiae and C. albicans may attenuate host vaginal mucosal TH17 immunity and contribute to mucosal colonization by C. albicans.</p