X-ray structure determinations of tetrakis(trifluoromet
hyl)dip
hosp
hane (
2c, mp -82
![](/images/entities/deg.gif)
C, triclinic,
P![](/images/entities/onemacr.gif)
; Z = 1,
a =529.7(3) pm,
b = 681.6(2) pm,
c = 802.8(3) pm,
hars/alpha.gif" BORDER=0> = 108.58(1)
![](/images/entities/deg.gif)
,
hars/beta2.gif" BORDER=0 ALIGN="middle"> = 99.66(1)
![](/images/entities/deg.gif)
,
hars/gamma.gif" BORDER=0 > = 103.29(1)
![](/images/entities/deg.gif)
, wR2 = 0.204)and -diarsane (
3c, mp -52
![](/images/entities/deg.gif)
C, monoclinic,
P2
1/
c; Z = 2,
a = 769.5(3) pm,
b = 750.0(3) pm,
c = 960.7(2) pm,
hars/beta2.gif" BORDER=0 ALIGN="middle"> = 105.26(1)
![](/images/entities/deg.gif)
, wR2 = 0.115), bot
h at -100(3)
![](/images/entities/deg.gif)
C, reveal t
he molecules to adopt t
he trans conformation in t
hesolid. Compared wit
h t
he tetramet
hyl derivatives, t
he E-E (224.6(2)/246.3(1) pm, E = P, As) and E-C(188.3(4)/201.3(7) pm) bonds are elongated by 4.5/4.8 pm and 3.4/3.4 pm, respectively. From gas electron diffractionstudies of dip
hosp
hane
2c a mixture of 85(10)% trans and 15(10)% gauc
he conformers can be deduced; diarsane
3c s
hows t
he trans form exclusively. T
he molecular parameters (E-E, 224.8(11)/245.2(6); E-C, 189.6(4)/201.2(4) pm) agree excellently wit
h t
hose determined for t
he crystalline state. As a result of quantum c
hemicalcalculations at Hartree-Fock and
hybrid density functional levels of t
heory using 6-311+G* basis sets, t
he gauc
heconformer of
hydrazine derivative
1c and t
he trans conformer of diarsane
3c are clearly lowest in energy. However,for dip
hosp
hane
2c t
he gauc
he and not t
he trans form is found to be slig
htly more stable. Variations of calculatedE-E and E-C bond lengt
hs are analyzed and compared wit
h corresponding values of t
he parent compoundsE
2H
4 (
1a to
3a) as well as t
he tetramet
hyl derivatives
1b to
3b.