Table 1 Analytical, mass spectral and NMR data for compounds I and 1–5
Compound Analysis (%)a and m/z NMRb
I
C, 58.0 (57.6); H, 2.8 (3.0)
1H: 7.26 (4 H, m, Hp), 6.80 [8 H, ddd, 3J(HmF) ≈ 3J(HmHp) 8.2, 4J(HmP) 1.3, Hm], 2.53
[4 H, vt, ¹| 2J(PH) ϩ 3J(PH)| 6.0, CH2]
542 (Mϩ), 429 ([M Ϫ C6H3F2]ϩ), 285 ([M Ϫ
2C6H3F2]ϩ) [Found: 542.059 96. C26H16F8P2
(Mϩ) requires 542.059 95]c
¯
²
19F-{1H}: Ϫ101.39 (X part of an AAЈX4XЈ4 spectrum)
31P-{1H}: Ϫ46.8 (A part of an AAЈX4XЈ4 spectrum)
1
C, 44.1 (44.8); H, 3.55 (3.2)d
1H: 7.44 (4 H, m), 6.87 (8 H, m), 4.40 [2 H, dm, 2J(HH) 17.6, C6H3FCH2], 4.01 [2 H,
775 ([M Ϫ BF4]ϩ), 739
d, J(HH) 17.6, C6H3FCH2], 3.75 (2 H, m, CH2), 3.42 (2 H, m, CH2), 2.01 [6 H, d,
2
([M Ϫ BF4 Ϫ Cl Ϫ H]ϩ), 627
([M Ϫ BF4 Ϫ Cl Ϫ C6H3F2]ϩ)e
4J(PH) 7.2, 4- and 5-CH3], 1.27 (3 H, s, 2-CH3)
19F-{1H}: Ϫ93.96 (2 F, s, CH2C6H3F), Ϫ101.22 (4 F, br s, C6H3F2), Ϫ152.50 (4 F, br s,
Ϫ
BF4
)
31P-{1H}: 60.0 [d, 1J(RhP) 139]
2 f
3
C, 41.6 (41.3); H, 3.6 (3.4)
C, 35.4 (35.5); H, 2.2 (2.2)
1384 ([M Ϫ Cl Ϫ C5Me5]ϩ), 1349 ([M Ϫ
2Cl Ϫ C5Me5]ϩ)e
1H: 3.05 (4 H, s, CH2), 1.39 (30 H, s, CH3)
19F: Ϫ125.90 [8 F, d, 3J(FoFm) 20.4, Fo], Ϫ146.96 [4 F, t, 3J(FmFp) 21.0, Fp], Ϫ159.23 (8
F, dd, Fm)
31P-{1H}: Ϫ23.3 (s)
4g
C, 48.7 (48.8); H, 3.8 (3.9); Cl, 3.4 (3.7)
1H: 7.76 (2 H, m, Hp), 7.40 (2 H, m, Hp), 6.96 [4 H, dd, 3J(HmF) ≈ 3J(HmHp) 8.5, Hm],
6.85 [4 H, dd, 3J(HmF) ≈ 3J(HmHp) 9.0, Hm], 3.15 (2 H, m, CH2), 2.91 (2 H, m, CH2),
1.66 [15 H, t, 4J(PH) 4.4, CH3]
815 ([M Ϫ BF4]ϩ), 780 ([M Ϫ BF4 Ϫ Cl]ϩ)e
19F-{1H}: Ϫ96.02 (4 F, s), Ϫ97.65 (4 F, s), Ϫ154.66 and Ϫ154.71 (4 F, 2s, ca. 1:4,
Ϫ
)
BF4
19F-{1H} [170 K, (CD3)2CO]: Ϫ93.50 (2 F, s, C6H3F2), Ϫ96.99 (2 F, s, C6H3FЈ2),
Ϫ97.62 (2 F, s, C6H3FЈ2), Ϫ98.11 (2 F, s, C6H3F2)
31P-{1H}: 28.3 [d, 1J(RhP) 147]
4
5
C, 43.2 (43.6); H, 2.8 (3.2)
1H: 7.47 (2 H, m, Hp), 7.37 [2 H, tt, J(HpF) ≈ 3J(HmHp) 7.2, Hp], 6.93 [4 H, dd,
905 ([M Ϫ BF4]ϩ), 870 ([M Ϫ BF4 Ϫ Cl]ϩ)e
3J(HmF) ≈ 3J(HmHp) 8.0, Hm], 6.78 [4 H, dd, 3J(HmF) ≈ 3J(HmHp) 9.3, Hm], 2.93 (4 H,
m, CH2), 1.37 [15 H, t, 4J(PH) 4.4, CH3]
19F-{1H}: Ϫ96.44 (4 F, s), Ϫ97.47 (4 F, s), Ϫ154.66 and Ϫ154.72 (4 F, 2s, ca. 1:4,
Ϫ
)
BF4
19F-{1H} [210 K, (CD3)2CO]: Ϫ96.35 (2 F, s, C6H3F2), Ϫ97.66 (2 F, s, C6H3FЈ2),
Ϫ98.57 (2 F, s, C6H3FЈ2), Ϫ99.22 (2 F, s, C6H3F2)
31P-{1H}: 1.0 (s)
a Required values are given in parentheses. b Unless stated otherwise, recorded in CDCl3 at 298 K. Data given as chemical shift (δ) [relative intensity,
multiplicity, J/Hz, assignment], s = singlet, d = doublet, t = triplet, vt = virtual triplet, m = multiplet. c EI. d Satisfactory analysis could not be
obtained due to contamination by other salts, such as 4, from which 1 could not be separated. e Positive-ion fast-atom bombardment with m-
nitrobenzyl alcohol as matrix. f Insufficiently soluble for NMR. g Crystallized with 1 Me2CO.
Table 2 Bond lengths (Å) and angles (Њ) with estimated standard
deviations (e.s.d.s) in parentheses for (C6H3F2-2,6)2PCH2CH2P(C6H3F2-
2,6) I
P᎐C(1)
P᎐C(11)
1.839(3)
1.829(3)
1.375(5)
1.354(5)
1.369(6)
1.366(11)
1.331(12)
1.376(8)
1.356(6)
1.391(5)
C(1)᎐C(1Ј)
P᎐C(21)
1.533(5)
1.837(3)
1.376(4)
1.357(3)
1.371(4)
1.375(5)
1.363(5)
1.373(4)
1.353(4)
1.385(4)
C(11)᎐C(12)
C(12)᎐F(12)
C(12)᎐C(13)
C(13)᎐C(14)
C(14)᎐C(15)
C(15)᎐C(16)
C(16)᎐F(16)
C(16)᎐C(11)
C(21)᎐C(22)
C(22)᎐F(22)
C(22)᎐C(23)
C(23)᎐C(24)
C(24)᎐C(25)
C(25)᎐C(26)
C(26)᎐F(26)
C(26)᎐C(21)
P᎐C(1)᎐C(1Ј)
C(1)᎐P᎐C(21)
P᎐C(11)᎐C(12)
P᎐C(11)᎐C(16)
C(12)᎐C(11)᎐C(16) 115.2(4)
C(11)᎐C(12)᎐F(12) 117.6(3)
C(11)᎐C(12)᎐C(13) 123.6(5)
C(13)᎐C(12)᎐F(12) 118.8(5)
C(12)᎐C(13)᎐C(14) 118.3(7)
C(13)᎐C(14)᎐C(15) 120.8(7)
C(14)᎐C(15)᎐C(16) 120.6(7)
C(15)᎐C(16)᎐F(16) 121.2(5)
C(15)᎐C(16)᎐C(11) 121.5(6)
C(11)᎐C(16)᎐F(16) 117.3(4)
108.3(3)
106.07(13)
125.9(2)
118.9(3)
C(1)᎐P᎐C(11)
C(11)᎐P᎐C(21)
P᎐C(21)᎐C(22)
P᎐C(21)᎐C(26)
C(22)᎐C(21)᎐C(26) 113.0(2)
C(21)᎐C(22)᎐F(22) 116.9(2)
C(21)᎐C(22)᎐C(23) 125.5(3)
C(23)᎐C(22)᎐F(22) 117.6(3)
C(22)᎐C(23)᎐C(24) 117.9(3)
C(23)᎐C(24)᎐C(25) 120.2(3)
C(24)᎐C(25)᎐C(26) 118.9(3)
C(25)᎐C(26)᎐F(26) 116.6(3)
C(25)᎐C(26)᎐C(21) 124.5(3)
C(21)᎐C(26)᎐F(26) 118.9(2)
99.09(13)
100.53(12)
118.0(2)
Fig. 3 Molecular structure of (C6H3F2-2,6)2PCH2CH2P(C6H3F2-2,6)2
I. Displacement ellipsoids are shown at the 30% probability level
128.7(2)
9J(FFЈ) = Ϫ0.4 Hz (the signs are relative). The value of δP is
similar to that of Ϫ44.4 for dfppe8 recorded in CDCl3, and the
value of δF is similar to that of Ϫ101.47 for P(C6H3F2-2,6)3.9
3
The absolute value of J(PF) is similar to that of PPh(C6F5)2,9
but is considerably lower than those of ca. 40 Hz observed
in the 2,6-difluorophenylphosphines PPh3Ϫx(C6H3F2-2,6)x (x =
1–3).9
Diphosphine I was further characterized by single-crystal
X-ray diffraction. The structure (Fig. 3) is very similar to those
of dppe10 and dfppe,11 with the centre of the C(1)᎐C(1Ј) bond
on a crystallographic centre of symmetry. Bond lengths and
angles are listed in Table 2. The bond lengths and the P᎐C᎐C,
C᎐P᎐C and C᎐C(P)᎐C angles are identical within experimental
error of those of dfppe.11 The most significant difference in the
geometry about the phosphorus atoms between the two struc-
tures is the C(P)᎐C᎐F angles. For dfppe these angles lie in the
range 118.8(3) to 121.4(4)Њ with an average of 120.2Њ, whereas
the C(P)᎐C᎐F angles of I are more acute, lying in the range
116.9(2) to 118.9(2)Њ with an average of 117.7Њ.
Treatment of [{RhCl(µ-Cl)(η5-C5Me5)}2] with I in refluxing
benzene for 16 h afforded in high yield [RhCl{η5-C5Me3-
1478
J. Chem. Soc., Dalton Trans., 1998, Pages 1477–1484