Caged Zn Photolysis in Zebrafish Whole Brains Reveals Subsecond Modulation of Dopamine Uptake.

Free, ionic zinc (Zn) modulates neurotransmitter dynamics in the brain. However, the sub-s effects of transient concentration changes of Zn on neurotransmitter release and uptake are not well understood. To address this lack of knowledge, we have combined the photolysis of the novel caged Zn compound [Zn(DPAdeCageOMe)] with fast scan cyclic voltammetry (FSCV) at carbon fiber microelectrodes in live, whole brain preparations from zebrafish ().

Probing the Ni -selective Response of Fluorescent Probe NiSensor-1 with the NiCast Photocaged Complex.

CTEA (N,N-bis[2-(carboxylmethyl)thioethyl]amine) is a mixed donor ligand that has been incorporated into multiple fluorescent sensors such as NiSensor-1 that was reported to be selective for Ni . Other metal ions such as Zn do not produce an emission response in aqueous solution. To investigate the coordination chemistry and selectivity of this receptor, we prepared NiCast, a photocage containing the CTEA receptor.

Detection and Quantification of Tightly Bound Zn in Blood Serum Using a Photocaged Chelator and a DNAzyme Fluorescent Sensor.

DNAzymes have emerged as a powerful class of sensors for metal ions due to their high selectivity over a wide range of metal ions, allowing for on-site and real-time detection. Despite much progress made in this area, detecting and quantifying tightly bound metal ions, such as those in the blood serum, remain a challenge because the DNAzyme sensors reported so far can detect only mobile metal ions that are accessible to bind the DNAzymes. To overcome this major limitation, we report the use of a photocaged chelator, XDPAdeCage to extract the Zn from the blood serum and then release the chelated Zn into a buffer using 365 nm light for quantification by an 8-17 DNAzyme sensor.

Coordination Chemistry of a Controlled Burst of Zn in Bulk Aqueous and Nanosized Water Droplets with a Zincon Chelator.

The light-induced photolysis of [Zn(NTAdeCage)] generates a temporally controlled burst of Zn, which is rapidly chelated by the free ligand Zincon. The [Zn(Zincon)] coordination progress is monitored using absorption spectroscopy in bulk aqueous buffer and reverse micelle environments. The [Zn(NTAdeCage)] photocage and free ligand Zincon have different reverse micelle locations that affect the [Zn(Zincon)] formation at the nanoscale compared to the bulk aqueous buffer.

On-demand guest release from MOF-5 sealed with nitrophenylacetic acid photocapping groups.

Recently, we demonstrated that triphenylacetic acid could be used to seal dye molecules within MOF-5, but guest release required the digestion of the framework by treatment with acid. We prepared the sterically bulky photocapping group [bis-(3-nitro-benzyl)-amino]-(3-nitro-phenyl)-acetic acid (PC1) that can prevent crystal violet dye diffusion from inside MOF-5 until removed by photolysis.

Zinc Photocages with Improved Photophysical Properties and Cell Permeability Imparted by Ternary Complex Formation.

Photocaged complexes can control the availability of metal ions to interrogate cellular signaling pathways. We describe a new photocage, {bis[(2-pyridyl)methyl]amino}(9-oxo-2-xanthenyl)acetic acid (XDPAdeCage, ), which utilizes a 2-xanthone acetic acid group to mediate a photodecarboxylation reaction. XDPAdeCage photolyzes with a quantum yield of 27%, and binds Zn with 4.

MOF Decomposition and Introduction of Repairable Defects Using a Photodegradable Strut.

Photoswitchable components can modulate the properties of metal organic frameworks (MOFs); however, photolabile building blocks remain underexplored. A new strut NPDAC (2-nitro-1,4-phenylenediacetic acid) that undergoes photodecarboxylation has been prepared and incorporated into a MOF, using post-synthetic linker exchange (PSLE) from the structural analogue containing PDAC (p-phenylenediacetic acid). Irradiation of NPDAC-MOF leads to MOF decomposition and concomitant formation of amorphous material.

Detection of adsorbates on emissive MOF surfaces with X-ray photoelectron spectroscopy.

Luminescent metal-organic frameworks (MOFs) have been explored extensively as potential probes for nitroaromatic molecules, which are common constituents of explosive devices. Guest encapsulation within MOF pores is often cited as the prerequisite for emission changes, but the evidence for this signal transduction mechanism is often inadequate. Using the unique bipyridyl ligand AzoAEpP (2,2'-bis[N,N'-(4-pyridyl)ethyl]diaminoazobenzene), we constructed two luminescent pillared paddle-wheel Zn2+ MOFs using aryl dicarboxylate ligands 1,4-naphthalenedicarboxylic acid (ABMOF-1) and benzene 1,4-dicarboxylic acid (ABMOF-2).

Publisher Correction: Neutron stardust and the elements of Earth.

In the version of this Comment originally published, the image was incorrectly credited to Chelsea Anne Bar; it should have been to Brett F. Thornton. This has now been corrected.

Emissive Azobenzenes Delivered on a Silver Coordination Polymer.

Azobenzene has become a ubiquitous component of functional molecules and polymeric materials because of the light-induced trans → cis isomerization of the diazene group. In contrast, there are very few applications utilizing azobenzene luminescence, since the excitation energy typically dissipates via nonradiative pathways. Inspired by our earlier studies with 2,2'-bis[ N,N'-(2-pyridyl)methyl]diaminoazobenzene (AzoAM oP) and related compounds, we investigated a series of five aminoazobenzene derivatives and their corresponding silver complexes.

The zinc paradigm for metalloneurochemistry.

Neurotransmission and sensory perception are shaped through metal ion-protein interactions in various brain regions. The term "metalloneurochemistry" defines the unique field of bioinorganic chemistry focusing on these processes, and zinc has been the leading target of metalloneurochemists in the almost 15 years since the definition was introduced. Zinc in the hippocampus interacts with receptors that dictate ion flow and neurotransmitter release.

Zn(2+) at a cellular crossroads.

Zinc is an essential micronutrient for cellular homeostasis. Initially proposed to only contribute to cellular viability through structural roles and non-redox catalysis, advances in quantifying changes in nM and pM quantities of Zn(2+) have elucidated increasing functions as an important signaling molecule. This includes Zn(2+)-mediated regulation of transcription factors and subsequent protein expression, storage and release of intracellular compartments of zinc quanta into the extracellular space which modulates plasma membrane protein function, as well as intracellular signaling pathways which contribute to the immune response.

A Zinc(II) Photocage Based on a Decarboxylation Metal Ion Release Mechanism for Investigating Homeostasis and Biological Signaling.

Metal ion signaling in biology has been studied extensively with ortho-nitrobenzyl photocages; however, the low quantum yields and other optical properties are not ideal for these applications. We describe the synthesis and characterization of NTAdeCage, the first member in a new class of Zn(2+) photocages that utilizes a light-driven decarboxylation reaction in the metal ion release mechanism. NTAdeCage binds Zn(2+) with sub-pM affinity using a modified nitrilotriacetate chelator and exhibits an almost 6 order of magnitude decrease in metal binding affinity upon uncaging.

Crystal structure of (pyridine-κN)bis(quinolin-2-olato-κ(2) N,O)copper(II) monohydrate.

The title complex, [Cu(C9H6NO)2(C5H4N)]·H2O, adopts a slightly distorted square-pyramidal geometry in which the axial pyridine ligand exhibits a long Cu-N bond of 2.305 (3) Å. The pyridine ligand forms dihedral angles of 79.