Element-Element Bonds. IX.1 Structures of Tetrakis(trifluoromethyl)diphosphane and -diarsane: Experimental and Theoretical Investigations
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- 作者：Gerd Becker ; Winfried Golla ; Joseph Grobe ; Karl Wilhelm Klinkhammer ; Duc Le Van ; Andreas H. Maulitz ; Otto Mundt ; Heinz Oberhammer ; and Martin Sachs
- 刊名：Inorganic Chemistry
- 出版年：1999
- 出版时间：March 22, 1999
- 年：1999
- 卷：38
- 期：6
- 页码：1099 - 1107
- 全文大小：155K
- 年卷期：v.38,no.6(March 22, 1999)
- ISSN：1520-510X
文摘
X-ray structure determinations of tetrakis(trifluoromethyl)diphosphane (2c, mp -82 
C, triclinic, P
; Z = 1, a =529.7(3) pm, b = 681.6(2) pm, c = 802.8(3) pm, 
= 108.58(1), 
= 99.66(1), 
= 103.29(1), wR2 = 0.204)and -diarsane (3c, mp -52 C, monoclinic, P21/c; Z = 2, a = 769.5(3) pm, b = 750.0(3) pm, c = 960.7(2) pm, = 105.26(1), wR2 = 0.115), both at -100(3) C, reveal the molecules to adopt the trans conformation in thesolid. Compared with the tetramethyl derivatives, the 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 diphosphane 2c a mixture of 85(10)% trans and 15(10)% gauche conformers can be deduced; diarsane3c shows the trans form exclusively. The molecular parameters (E-E, 224.8(11)/245.2(6); E-C, 189.6(4)/201.2(4) pm) agree excellently with those determined for the crystalline state. As a result of quantum chemicalcalculations at Hartree-Fock and hybrid density functional levels of theory using 6-311+G* basis sets, the gaucheconformer of hydrazine derivative 1c and the trans conformer of diarsane 3c are clearly lowest in energy. However,for diphosphane 2c the gauche and not the trans form is found to be slightly more stable. Variations of calculatedE-E and E-C bond lengths are analyzed and compared with corresponding values of the parent compoundsE2H4 (1a to 3a) as well as the tetramethyl derivatives 1b to 3b.
C, triclinic, P; Z = 1, a =529.7(3) pm, b = 681.6(2) pm, c = 802.8(3) pm, = 108.58(1), = 99.66(1), = 103.29(1), wR2 = 0.204)and -diarsane (3c, mp -52 C, monoclinic, P21/c; Z = 2, a = 769.5(3) pm, b = 750.0(3) pm, c = 960.7(2) pm, = 105.26(1), wR2 = 0.115), both at -100(3) C, reveal the molecules to adopt the trans conformation in thesolid. Compared with the tetramethyl derivatives, the 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 diphosphane 2c a mixture of 85(10)% trans and 15(10)% gauche conformers can be deduced; diarsane3c shows the trans form exclusively. The molecular parameters (E-E, 224.8(11)/245.2(6); E-C, 189.6(4)/201.2(4) pm) agree excellently with those determined for the crystalline state. As a result of quantum chemicalcalculations at Hartree-Fock and hybrid density functional levels of theory using 6-311+G* basis sets, the gaucheconformer of hydrazine derivative 1c and the trans conformer of diarsane 3c are clearly lowest in energy. However,for diphosphane 2c the gauche and not the trans form is found to be slightly more stable. Variations of calculatedE-E and E-C bond lengths are analyzed and compared with corresponding values of the parent compoundsE2H4 (1a to 3a) as well as the tetramethyl derivatives 1b to 3b.