“Hydrogen ditelluride”的意思、由来-开放百科全书

Hydrogen ditelluride or ditellane is an unstable hydrogen dichalcogenide containing two tellurium atoms per molecule, with structure HTeTeH. Hydrogen ditelluride is interesting to theorists because its molecule is simple yet asymmetric (with no centre of symmetry) and is predicted to be one of the easiest to detect parity violation, in which the left handed molecule has differing properties to the right handed one.

Production

Hydrogen ditelluride can possibly be formed at the tellurium cathode in electrolysis in acid.^[2] When electrolysed in alkaline solutions, a tellurium cathode produces ditelluride Te₂²⁻ ions, as well as Te²⁻ and a red polytelluride. The greatest amount of ditelluride is made when pH is over 12.^[3]

Apart from its speculative detection in electrolysis, ditellane has been detected in the gas phase produced from di-sec-butylditellane.^[4]^[5]

Properties

Hydrogen ditelluride has been investigated theoretically, with various properties predicted. The molecule is twisted with a C₂ symmetry. There are two enantiomers. Hydrogen ditelluride is equal simplest in its unsymmetrical molecule, any simpler molecule will not have the required low symmetry. The equilibrium geometry (not counting zero point energy or vibrational energy) has the molecule with 2.879 Å between the tellurium atoms, and 1.678 Å between hydrogen and tellurium. The H-Te-Te angle is 94.93°. The angle of lowest energy between the two H-Te bonds (dihedral angle) is 89.32°. The trans cofiguration is higher in energy (3.71 kcal/mol), and the cis would be even higher (4.69 kcal/mol).^[6]

Being chiral the molecule is predicted show evidence of parity violation, however this may get interference from stereomutation tunneling, where the P enantiomer and M enantiomer spontaneously convert into each other by quantum tunneling. The parity violation effect on energy comes about from virual Z boson exchanges between the nucleus and electrons.^[7] It is proportional to the cube of the atomic number, so is stronger in tellurium molecules than others higher up in the periodic table (eg O, S, Se). Because of parity violation, the energy of the two enantiomers differs, and is likely to be higher in this molecule than most moleculess. So an effort is underway to observe this so-far undetected effect. The tunneling effect is reduced by higher masses, so that the deuterium form, D₂Te₂ will show less tunneling. In a tortional vibrational mode the molecule can twist back and forward storing energy. Seven different quantum vibration levels are predicted below the energy to jump to the other enantiomer. The levels are numbered v_t=0 up to 6. The sixth level is predicted to be split into two energy levels because of quantum tunneling.^[8] The parity violation energy is calculated as 3×10⁻⁹ cm⁻¹ or 90 Hz.^[8]

The different vibrational modes for H₂Te are symmetrical stretch of H-Te, symmetrical bend of ∠H-Te-Te, torsion, stretch Te-Te, asymmetrical stretch H-Te, asymmetrical bend of ∠H-Te-Te.^[8] The time to tunnel between enantiomers is only 0.6 ms for H₂Te₂, but is 66000 seconds for T₂Te₂.^[8]

There are organic derivatives, in which the hydrogen is replaced by organic groups. One example is bis-(2,4,6-tributylphenyl)ditellane.^[9] Others are diphenylditellane and 1,2-bis(cyclohexylmethyl)ditellane.

References

1. ^{{cite book|last1=Macintyre|first1=Jane E.|title=Dictionary of Inorganic Compounds, Supplement 3|date=1995|publisher=CRC Press|isbn=9780412491108|page=287|url=https://books.google.com.au/books?id=YY2N7nOhBoIC&pg=PA287|language=en}}
2. ^{{cite journal|last1=Awad|first1=S. A.|title=POISONING EFFECT OF TELLURIDE IONS ON HYDROGEN EVOLUTION AND CATHODIC FORMATION OF HYDROGEN DITELLURIDE|journal=The Journal of Physical Chemistry|date=May 1962|volume=66|issue=5|pages=890–894|doi=10.1021/j100811a031}}
3. ^{{cite journal|last1=Alekperov|first1=A I|title=Electrochemistry of Selenium and Tellurium|journal=Russian Chemical Reviews|date=30 April 1974|volume=43|issue=4|pages=235–250|doi=10.1070/RC1974v043n04ABEH001803}}
4. ^{{cite book|last1=Macintyre|first1=Jane E.|title=Dictionary of Inorganic Compounds, Supplement 3|date=1995|publisher=CRC Press|isbn=9780412491108|page=287|url=https://books.google.com.au/books?id=YY2N7nOhBoIC&pg=PA287|language=en}}
5. ^{{cite journal|last1=Hop|first1=Cornelis E. C. A.|last2=Medina|first2=Marco A.|title=H2Te2 Is Stable in the Gas Phase|journal=Journal of the American Chemical Society|date=April 1994|volume=116|issue=7|pages=3163–3164|doi=10.1021/ja00086a072}}
6. ^{{cite journal|last1=BelBruno|first1=Joseph J.|title=Ab Initio Calculations of the Rotational Barriers in H₂Te₂ and (CH₃)₂Te₂|journal=Heteroatom Chemistry|date=1997|volume=8|issue=3|pages=199–202|doi=10.1002/(SICI)1098-1071(1997)8:3<199::AID-HC1>3.0.CO;2-8}}
7. ^{{cite book|last1=Senami|first1=Masato|last2=Inada|first2=Ken|last3=Soga|first3=Kota|last4=Fukuda|first4=Masahiro|last5=Tachibana|first5=Akitomo|title=Concepts, Methods and Applications of Quantum Systems in Chemistry and Physics|date=2018|publisher=Springer, Cham|isbn=9783319745817|pages=95–106|language=en|chapter=Difference of Chirality of the Electron Between Enantiomers of H$$_$$X$$_$$|doi=10.1007/978-3-319-74582-4_6}}
8. ^¹²³{{cite journal|last1=Gottselig|first1=Michael|last2=Quack|first2=Martin|last3=Stohner|first3=Jürgen|last4=Willeke|first4=Martin|title=Mode-selective stereomutation tunneling and parity violation in HOClH+ and H2Te2 isotopomers|journal=International Journal of Mass Spectrometry|date=April 2004|volume=233|issue=1–3|pages=373–384|doi=10.1016/j.ijms.2004.01.014}}
9. ^{{cite journal|last1=Lickiss|first1=P. D.|title=Chapter 9. Organometallic chemistry. Part (ii) Main-group elements|journal=Annual Reports Section "B" (Organic Chemistry)|date=1988|volume=85|page=263|doi=10.1039/OC9888500241}}

Production

Properties

Related

References