Structural Diversity and Properties of M(II) Coordination Compounds Constructed by 3‑Hydrazino-4-amino-1,2,4-triazole Dihydrochloride as Starting Material

Twelve metal coordination compounds with two triazole derivatives, namely, {[Mn­(HATr)₂]­(ClO₄)₂}_<i>n</i> (<b>1</b>), [Mn­(HATr)₃]­Cl­(ClO₄) (<b>2</b>), [Co₃(ATr)₆­(H₂O)₆]­(ClO₄)₆·4.5H₂O (<b>3</b>), [Co­(HATr)₃]­Cl­(ClO₄) (<b>4</b>), [Co₂Cl₂(HATr)₂­(H₂O)₂(CH₃OH)₂]­Cl₂·2H₂O (<b>5</b>), [Ni₃(ATr)₆­(H₂O)₆]­(ClO₄)₆·4.5H₂O (<b>6</b>), [Ni­(HATr)₃]­Cl­(ClO₄) (<b>7</b>), [Ni₂Cl₂(HATr)₂­(H₂O)₄]­(ClO₄)₂·4H₂O (<b>8</b>), [Ni₂(HATr)₂­(H₂O)₆]­(ClO₄)₄·2H₂O (<b>9</b>), {[Zn­(HATr)₂]­(ClO₄)₂}_<i>n</i> (<b>10</b>), [Zn­(HATr)₃]­Cl­(ClO₄) (<b>11</b>), and {[Cd₄(HATr)₈]­(CdCl₄)­Cl₂(ClO₄)₄}_<i>n</i> (<b>12</b>), when HATr = 3-hydrazino-4-amino-1,2,4-triazole and ATr = 4-amino-1,2,4-triazole, were prepared under diverse conditions and structurally characterized. Compounds <b>1</b>, <b>10</b> and <b>12</b> exhibit one-dimensional zigzag chain structures; <b>2</b>, <b>4</b>, <b>7</b>, and <b>11</b> possess mononuclear structures; <b>3</b> and <b>6</b> display trinuclear structures, while <b>5</b>, <b>8</b>, and <b>9</b> feature binuclear structures. Hydrogen bonds link these compounds into three-dimensional structures. The thermal stability and energetic properties also were determined

Reactivity Switch Enabled by Counterion: Highly Chemoselective Dimerization and Hydration of Terminal Alkynes

A counterion-controlled reactivity tuning in Pd-catalyzed highly chemoselective and regioselective dimerization and hydration of terminal alkynes is reported. The use of acetate as counterion favors the formation of an alkenyl alkynyl palladium intermediate which forms hitherto less reported 1,3-diaryl-substituted conjugated enynes after reductive elimination. Using chloride, which is a better leaving group, leads to anion exchange on the alkenylpalladium intermediate with hydroxide which after reductive elimination and tautomerization delivered the hydration products

Editable TiO₂ Nanomaterial-Modified Paper in Situ for Highly Efficient Detection of Carcinoembryonic Antigen by Photoelectrochemical Method

In this work, a versatile photoelectrochemical paper-based sensor based on N-carbon dots/TiO₂–Pt-modified paper in situ is developed for sensitive detection of carcinoembryonic antigen (CEA) in clinical serum samples. Interconnected cellulose fibers on paper provide a porous, 3D, and flexible substrate for photoelectrochemical sensing. In situ modification of N-carbon dots/TiO₂–Pt with editable structures on paper significantly increases the conductivity, widens the adsorption range, and enhances the photoelectrochemical ability, which enables the higher sensitivity and flexibility compared with traditional rigid sensors. On the basis of this novel protocol, a miniaturized and portable origami device realizes the CEA determination with a low detection limit of 1.0 pg mL^–1 and a wide linear range from 0.002 to 200 ng mL^–1. Thanks to the good biocompatibility, the paper-based device provides a new avenue for the detection of CEA on the cell surface which is promising for portable diagnostics in early tumor warning