diphosphene

{{for| the functional group| Diphosphene (functional group)}}

{{Chembox

|Watchedfields = changed

|verifiedrevid = 451633982

|ImageFile = Diphosphene.png

|ImageSize = 150px

|ImageFile_Ref = {{Chemboximage|correct|??}}

|ImageName = Ball and stick model of diphosphene molecule

|Section1={{Chembox Identifiers

|CASNo_Ref = {{cascite|correct|??}}

|CASNo = 41916-72-7

|PubChem = 142559

|ChemSpiderID = 125761

|ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

|SMILES = P=P

|StdInChI = 1S/H2P2/c1-2/h1-2H

|StdInChI_Ref = {{stdinchicite|correct|chemspider}}

|StdInChIKey = SWJAOBXRZSMKNS-UHFFFAOYSA-N

|StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}

}}

|Section2={{Chembox Properties

| Formula = {{Chem2|P2H2}}

| MolarMass = 63.96340 g·mol⁻¹

}}

|Section9={{Chembox Related

|OtherCations = diphosphenes

|OtherAnions = diazene

|OtherFunction_label = Binary azenes

|OtherFunction = triazene
tetrazene

|OtherCompounds = ammonia
diazane
triazane

}}

}}

Diphosphene is a compound having the formula {{chem2|(PH)2}}. It exists as two geometric isomers, E and Z.{{cite journal | last = Lu | first = T. |author2=Simmonett, A. C. |author3=Evangelista, F. A. |author4=Yamaguchi, Y. |author5=Schaefer, H. F.| title = Diphosphene and Diphosphinylidene | journal = The Journal of Physical Chemistry A | year = 2009 | volume = 113 | issue = 47 | pages = 13227–13236 | doi = 10.1021/jp904028a | pmid = 19594123 | bibcode = 2009JPCA..11313227L }} Diphosphene is also the parent member of the entire class of diphosphene compounds with the formula {{chem2|(PR)2}}, where R is an organyl group.{{cite journal | last = Yoshifuji | first=M. |author2=Shibayama, K. |author3=Inamoto, N. |author4=Hirotsu, K. |author5=Higuchi, T. | title = Reaction of the diphosphene ArP=PAr (Ar = 2,4,6-Bu^t₃C₆H₂) with sulphur: isolation and X-ray structure of the diphosphene monosulphide | journal = Journal of the Chemical Society, Chemical Communications | year = 1983 | volume = 1983 | issue = 16 | pages = 862–863 | doi = 10.1039/C39830000862}}

Visible radiation induces cis-trans isomerization,{{cite journal |last1=Caminade |first1=Anne-Marie |last2=Verrier |first2=Martine |last3=Ades |first3=Claude |last4=Paillous |first4=Nicole |last5=Koenig |first5=Max |date=1984-01-01 |title=Laser irradiation of a diphosphene: evidence for the first cis–trans isomerization |journal=J. Chem. Soc., Chem. Commun. |language=en |issue=13 |pages=875–877 |doi=10.1039/c39840000875 |issn=0022-4936}} although further irradiation can excite the molecule to a triplet diradical state. In triplet trans-HPPH, the P-P bond length is predicted to be 2.291 Å. It is not only longer than the P-P double bond in ground state trans-bis(2,4,6-tri-tert-butylphenyl)diphosphene, but also longer than that of P-P single bond in {{chem2|H2P\sPH2}}. Calculation of the dihedral angle of trans-HPPH suggests that it is almost 90 degree, which means the formation of $\backslash pi$ and $\backslash pi^*$ P-P bonds is forbidden and σ bond is enhanced.{{cite journal |last1=Lu |first1=Tongxiang |last2=Hao |first2=Qiang |last3=Simmonett |first3=Andrew C. |last4=Evangelista |first4=Francesco A. |last5=Yamaguchi |first5=Yukio |last6=Fang |first6=De-Cai |last7=Schaefer |first7=Henry F. |date=2010-10-14 |title=Low-Lying Triplet States of Diphosphene and Diphosphinylidene |journal=The Journal of Physical Chemistry A |volume=114 |issue=40 |pages=10850–10856 |bibcode=2010JPCA..11410850L |doi=10.1021/jp105281w |issn=1089-5639 |pmid=20836526}}