Detection of 1H-Triphosphirene (c-HP3) and 2-Triphosphenylidene (HP3): The Isovalent Counterparts of 1H-Triazirine (c-HN3) and Hydrazoic Acid (HN3)

Super-high carrier mobilities and excellent thermoelectric performances of Tri-Tri group-VA monolayers

High-performance thermoelectric materials in theoretical and experimental research are mostly composed of expensive, scarce, heavy elements and rarely of single light elements, which severely limit their application and development. Based on density functional and semiclassical Boltzmann transport theory, we determine that a stable phosphorene allotrope, named Tri-Tri phosphorene, has super-high electron mobility (23845.29 cm2 V-1 s-1) much higher than those of most two-dimension materials. Moreover, its optimized maximum ZT can reach up to 3.43 at room temperature (4.83 at 500 K and 5.92 at 700 K), exhibiting highly favorable prospects in practical thermoelectric systems. Motivated by the excellent properties of Tri-Tri phosphorene, we further demonstrate the structural stability of Tri-Tri arsenene and Tri-Tri antimonene and predict that the two Tri-Tri structures also have high Seebeck coefficients and electron mobilities. Their lattice thermal conductivities are dramatically decreased compared with Tri-Tri phosphorene. Thus, their predicted thermoelectric performances are also excellent, with maximum ZT values of 4.12 (Tri-Tri arsenene) and 3.54 (Tri-Tri antimonene) at room temperature. The low layer moduli of the three Tri-Tri structures indicate that they have high mechanical flexibility and suitability for current device assemblies. All these desirable properties make Tri-Tri group-VA materials promising for future applications in thermoelectric devices.

Mechanistical study on the formation of hydroxyacetone (CH3COCH2OH), methyl acetate (CH3COOCH3), and 3-hydroxypropanal (HCOCH2CH2OH) along with their enol tautomers (prop-1-ene-1,2-diol (CH3C(OH)CHOH), prop-2-ene-1,2-diol (CH2C(OH)CH2OH), 1-methoxyethen-1-ol (CH3OC(OH)CH2) and prop-1-ene-1,3-diol (HOCH2CHCHOH)) in interstellar ice analogs

We unravel, for the very first time, the formation pathways of hydroxyacetone (CH₃COCH₂OH), methyl acetate (CH₃COOCH₃), and 3-hydroxypropanal (HCOCH₂CH₂OH), as well as their enol tautomers within mixed ices of methanol (CH₃OH) and acetaldehyde (CH₃CHO) analogous to interstellar ices in the ISM exposed to ionizing radiation at ultralow temperatures of 5 K. Exploiting photoionization reflectron time-of-flight mass spectrometry (PI-ReToF-MS) and isotopically labeled ices, the reaction products were selectively photoionized allowing for isomer discrimination during the temperature-programmed desorption phase. Based on the distinct mass-to-charge ratios and ionization energies of the identified species, we reveal the formation pathways of hydroxyacetone (CH₃COCH₂OH), methyl acetate (CH₃COOCH₃), and 3-hydroxypropanal (HCOCH₂CH₂OH) via radical-radical recombination reactions and of their enol tautomers (prop-1-ene-1,2-diol (CH₃C(OH)CHOH), prop-2-ene-1,2-diol (CH₂C(OH)CH₂OH), 1-methoxyethen-1-ol (CH₃OC(OH)CH₂) and prop-1-ene-1,3-diol (HOCH₂CHCHOH)) via keto-enol tautomerization. To the best of our knowledge, 1-methoxyethen-1-ol (CH₃OC(OH)CH₂) and prop-1-ene-1,3-diol (HOCH₂CHCHOH) are experimentally identified for the first time. Our findings help to constrain the formation mechanism of hydroxyacetone and methyl acetate detected within star-forming regions and suggest that the hitherto astronomically unobserved isomer 3-hydroxypropanal and its enol tautomers represent promising candidates for future astronomical searches. These enol tautomers may contribute to the molecular synthesis of biologically relevant molecules in deep space due to their nucleophilic character and high reactivity.

Diazophosphane HPN2

Diazophosphane HPN₂, a heavy analogue of hydrazoic acid (HN₃), has been synthesized at low temperature (10 K) through photolytic reactions of molecular nitrogen (N₂) with phosphine (PH₃) and phosphaketene (HPCO) under irradiations at 193 and 365 nm, respectively. The characterization of HPN₂ and its isotopologues DPN₂ and HP¹⁵N₂ by matrix-isolation IR and UV-vis spectroscopy is supported by quantum chemical calculations at the CCSD(T)-F12a/cc-pVTZ-F12 level of theory. Upon irradiation at 266 nm, the P-N bond in HPN₂ breaks, whereas its photolysis at 193 nm generates the elusive phosphinyl radical ^•PN₂.