New heteromultifunctional fluoroaromatic bis(phosphinimine)ligands and their complexes.Synthesis and characterization of new ligands(including X-ray structures of 4,6-(CN)2C6F2-1-(N=P(Ph)2CH 2PPh2)-3-(N=PPh3)

Article abstract of DOI:10.1021/om950767d

Reaction of 1,3-dicyanotetrafluorobenzene with trimethylsilyl phosphinimines proceeds through stepwise substitution on the fluoroaromatic to yield mono- and ultimately disubstituted derivatives of the form 4,6-(CN)₂C₆F₂-1-A-S-B. Two molar equivalents of a bifunctional phosphinophosphoranimines, Me₃SiNP(Ph)₂CH₂PPh₂, result in a dual substitution giving 1 (A = B = (N=P(Ph)₂CH₂PPh₂)), whereas 1 equiv of the trimethylsilyl phosphinimine gives the monosubstituted derivative. Treatment of the monosubstituted derivative with a second 1 equiv of the same or a different phosphinimine gives doubly substituted derivatives which can have the same or different phosphorus substituents, e.g. 2,A = (N=P(Ph)₂CH₂P(Ph)₂), B = (N=PPh₃), and 3, A = (N=P(Ph)₂CH₂PPh₂), B = (N=PPh₂-Me). Compounds 1, 4,6-(CN)₂C₆F₂-1,3-bis(N=P(Ph) ₂CH₂PPh₂), and 2, 4,6-(CN)₂C₆F₂-1-(N=P(Ph)₂CH ₂PPh₂)-3-(N=PPh₃), have been structurally characterized. In 1, the P(1)=N(1) bond length is 1.581(3) ?, the P(3)=N(2) bond length is 1.569(4) ?, the P(1)-N(1)-C(6) angle is 132.1(3)°, and the P(3)-N(2)-C(2) angle is 133.2(3)°. For 2, the P(2)=N(1) bond length (in the Ph₃P=N unit) is 1.578(4) ?, the P(3)=N(2) bond length in the Ph₂PCH₂Ph₂P=N unit) is 1.585(4) ?, the P(2)-N(1)-C(2) angle is 134.7(4)°, and the P(3)-N(2)-C(6) angle is 129.9-(4)°. 2 reacted readily with [Rh(CO)₂Cl]₂ to form the mono metallic chelated Rh complex 4, 4,6-(CN)₂C₆F₂-3-(N=PPh ₃)-1-(N=P(Ph)₂CH₂P(Ph)₂Rh(CO)Cl). 1 reacts with both 1 equiv and 0.5 equiv Of [Rh(CO)₂Cl]₂ to form respectively 4,6-(CN)₂C₆F₂-1,3-bis(N=P(Ph) ₂CH₂P(Ph)₂Rh-(CO)Cl), 5, and 4,6-(CN)₂C₆F₂-1,3-bis(N=P(Ph) ₂CH₂P(Ph)₂)Rh(CO)Cl, 6. The half-metalated complex 6 can be converted to 5 with a second aliquot of the Rh precursor, and the dimetalated complex 5 can be converted to the half-metalated complex 6 by reaction of 5 with more ligand. The bis(phosphine) chelate structure of 6, the dimetalated complex, was deduced from the complex second-order ³¹P NMR spectrum solved by simulation. The two P^III are trans coordinated to the Rh center, and the two N are not coordinated. There is no p^III_p^III or p^v_p^v coupling but each P^III is coupled to two magnetically inequivalent P^v. Structural characterization of the dimetalated complex 5 shows a symmetrically substituted complex containing two Rh centers with a square planar geometry around each Rh(I) with the CO cis to the phosphine. Bond angles and lengths are typical for the Rh(I) square planar chelate complex structures. The P(I)-N(I) distance of 1.61(1) ? in the complex is normal for a coordinated iminophosphoranyl group. The directly bound Rh-P^III distance of 2.206-(4) ? also lies within the range found in many Rh(I) phosphine complexes of this type.

Full text of DOI:10.1021/om950767d

Organometallics 1996, 15, 1033-1041
1033
New Heter om u ltifu n ction a l F lu or oa r om a tic
Bis(p h osp h in im in e) Liga n d s a n d Th eir Com p lexes.
Syn th esis a n d Ch a r a cter iza tion of New Liga n d s
(In clu d in g X-r a y Str u ctu r es of
4,6-(CN)2C6F 2-1-(NdP (P h )2CH2P P h 2)-3-(NdP P h 3) a n d
4,6-(CN)2C6F 2-1,3-bis(NdP (P h )2CH2P P h 2)) a n d Th eir
Rh od iu m (I) Com p lexes, In clu d in g th e Str u ctu r e of th e
Novel Dim eta llic Com p lex
4,6-(CN)2C6F 2-1,3-bis(NdP (P h )2CH2P (P h )2Rh (CO)Cl)
J in Li, Robert McDonald, and Ronald G. Cavell*
Department of Chemistry, University of Alberta, Edmonton, AB, Canada T6G 2G2
Received September 26, 1995X
Reaction of 1,3-dicyanotetrafluorobenzene with trimethylsilyl phosphinimines proceeds
through stepwise substitution on the fluoroaromatic to yield mono- and ultimately disub-
stituted derivatives of the form 4,6-(CN)2C6F2-1-A-3-B. Two molar equivalents of a
bifunctional phosphinophosphoranimines, Me3SiNP(Ph)2CH2PPh2, result in a dual substitu-
tion giving 1 (A ) B ) (NdP(Ph)2CH2PPh2)), whereas 1 equiv of the trimethylsilyl
phosphinimine gives the monosubstituted derivative. Treatment of the monosubstituted
derivative with a second 1 equiv of the same or a different phosphinimine gives doubly
substituted derivatives which can have the same or different phosphorus substituents, e.g.
2, A ) (NdP(Ph)2CH2P(Ph)2), B ) (NdPPh3), and 3, A ) (NdP(Ph)2CH2PPh2), B ) (NdPPh2-
Me). Compounds 1, 4,6-(CN)2C6F2-1,3-bis(NdP(Ph)2CH2PPh2), and 2, 4,6-(CN)2C6F2-1-
(NdP(Ph)2CH2PPh2)-3-(NdPPh3), have been structurally characterized. In 1, the P(1)dN(1)
bond length is 1.581(3) Å, the P(3)dN(2) bond length is 1.569(4) Å, the P(1)-N(1)-C(6) angle
is 132.1(3)°, and the P(3)-N(2)-C(2) angle is 133.2(3)°. For 2, the P(2)dN(1) bond length
(in the Ph3PdN unit) is 1.578(4) Å, the P(3)dN(2) bond length in the Ph2PCH2Ph2PdN unit)
is 1.585(4) Å, the P(2)-N(1)-C(2) angle is 134.7(4)°, and the P(3)-N(2)-C(6) angle is 129.9-
(4)°. 2 reacted readily with [Rh(CO)2Cl]2 to form the mono metallic chelated Rh complex 4,
4,6-(CN)2C6F2-3-(NdPPh3)-1-(NdP(Ph)2CH2P(Ph)2Rh(CO)Cl). 1 reacts with both 1 equiv and
0.5 equiv of [Rh(CO)2Cl]2 to form respectively 4,6-(CN)2C6F2-1,3-bis(NdP(Ph)2CH2P(Ph)2Rh-
(CO)Cl), 5, and 4,6-(CN)2C6F2-1,3-bis(NdP(Ph)2CH2P(Ph)2)Rh(CO)Cl, 6. The half-metalated
complex 6 can be converted to 5 with a second aliquot of the Rh precursor, and the
dimetalated complex 5 can be converted to the half-metalated complex 6 by reaction of 5
with more ligand. The bis(phosphine) chelate structure of 6, the dimetalated complex, was
deduced from the complex second-order 31P NMR spectrum solved by simulation. The two
PIII are trans coordinated to the Rh center, and the two N are not coordinated. There is no
PIII-PIII or PV-PV coupling, but each PIII is coupled to two magnetically inequivalent PV.
Structural characterization of the dimetalated complex 5 shows a symmetrically substituted
complex containing two Rh centers with a square planar geometry around each Rh(I) with
the CO cis to the phosphine. Bond angles and lengths are typical for the Rh(I) square planar
chelate complex structures. The P(1)-N(1) distance of 1.61(1) Å in the complex is normal
for a coordinated iminophosphoranyl group. The directly bound Rh-PIII distance of 2.206-
(4) Å also lies within the range found in many Rh(I) phosphine complexes of this type.
In tr od u ction
were effective ligands for binding both the early and the
late transition metals.2
In the previous work, only monosubstituted deriva-
tives were obtained2 from both the 1,2- and 1,4-dicy-
anofluoroaromatics. Herein we report that, when R is
the 1,3-dicyanofluoroaromatic, the reaction yields a
series of disubstituted derivatives, two of which have
We recently reported that silylated heterodifunctional
phosphine-phosphinimines1 (Scheme 1) could be easily
converted to imino fluoroaromatic derivatives by a
substitution on the imine center and that such species
X Abstract published in Advance ACS Abstracts, December 15, 1995.
(1) Katti, K. V.; Cavell, R. G. Inorg. Chem. 1989, 28, 413.
(2) Katti, K. V.; Santarsiero, B. D.; Pinkerton, A. A.; Cavell, R. G.
Inorg. Chem. 1993, 32, 5919.
0276-7333/96/2315-1033$12.00/0 © 1996 American Chemical Society

1034 Organometallics, Vol. 15, No. 3, 1996
Li et al.
Sch em e 1
Sch em e 2
F igu r e 1. Top: Perspective views of 1 showing the atom-
labeling scheme. Non-hydrogen atoms are represented by
Gaussian ellipsoids at the 20% probability level. Hydrogen
atoms are not shown. Bottom: Alternate view of the
molecule with the C(1)-C(6) ring oriented almost edge-
on.
been structurally characterized. These multifunctional
ligands also readily react with [Rh(CO)2Cl]2 to form
mono- and dimetallic Rh(I) complexes, and one of the
resultant complexes (the novel dimetallic derivative) has
been structurally characterized.
Resu lts a n d Discu ssion
Syn th esis, P r op er ties, a n d Str u ctu r e. The reac-
tion of 1,3-dicyanotetraflurobenzene with 2 equiv of
trimethylsilyl phosphinimine in refluxing toluene gave
the disubstituted fluoroaromatic derivatives 1-3 in good
yield. In all cases fluorine atoms para to CN groups
were replaced. Reactions proceeded smoothly with a 1:2
ratio of reagents to yield directly the equivalently
disubstituted products or they could be carried out in a
sequential stepwise fashion, that is, using initially 1
equiv of R3PdNSiMe3 to form the monosubstituted
derivative and then using a second 1 equiv of either the
same or a different silyl phosphinimine to form the
disubstituted derivative. The silyl iminophosphorus
reactant may be either a simple iminophosphorane,
R3PdNSiMe3, or the more complex bifunctional imino-
phosphorano phosphines such as Ph2PCH2PPh2dN-
F igu r e 2. Perspective view of 2 showing the atom-labeling
scheme. Non-hydrogen atoms are represented by Gaussian
ellipsoids at the 20% probability level. The methylene
hydrogens of the NdPPh2CH2PPh2 group are shown arti-
ficially small, while those of the phosphine phenyl groups
are not shown.
1
para to the electron-withdrawing activating groups, CN,
in 1,3-(CN)2C6F4, are the most reactive and these
fluorines are sequentially replaced. In contrast, only
one of the fluorine atoms para to CN groups in 1,2-
(CN)2C6F4 could be eliminated to form the imine and
second substitution was not obtained,2 because the first
imine substitution electronically deactivates the ortho
position.
SiMe3 (Scheme 2).
Two of these disubstituted ligands, 1 and 2, have been
structurally characterized. Both mono- and disubsti-
tuted fluoroaromatic compounds are crystalline, air-
stable solids which are soluble in most common organic
solvents. The disubstituted compounds are less soluble
than the monosubstituted analogs. In the reactions
shown in Scheme 2, the two fluorine atoms which are

Fluoroaromatic Bis(phosphinimine) Ligands
Organometallics, Vol. 15, No. 3, 1996 1035
Ta ble 1. P h osp h or u s-31 NMRa Da ta for Com p ou n d s 1-6
δ(PIII
)
1J PRh
(Hz)
compdb
no. (ppm)
δ(PV) (ppm)
2J PP (Hz)
4,6-(CN)2C6F2-1,3-bis(NdPPh2CH2PPh2)
4,6-(CN)2C6F2-1-(NdPPh2CH2PPh2)-3-(N)PPh3)
4,6-(CN)2C6F2-1-(N)PPh2CH2PPh2)-3-(N)PPh2Me)
1
2
3
4
-29.5 10.00
49.0
47.8
-28.7 10.30 (PPh2 unit), 8.40 (PPh3 group)
-29.2 10.30 (PPh2 unit), 10.00 (PPh2Me group) 48.4
39.2 44.00 (PPh2 unit), 11.90 (PPh3 group)
30.9
163.3
164.9
4,6-(CN)2C6F2-3-(NdPPh3)-1-(NdP(Ph)2CH2P(Ph)2Rh(CO)Cl
5
6
38.8 41.60
24.2 0.26
32.5
4,6-(CN)2C6F2-1,3-bis(NdP(Ph)2CH2P(Ph)2Rh(CO)Cl)
4,6-(CN)2C6F2-1,3-bis(N)PPh2CH2PPh2)Rh(CO)Cl
1.75,1.85 128.6
a
b
Spectra obtained in CDCl3 solution; ppm vs 85% H3PO4. Positive values indicate resonance to low field of standard. The substituted
aromatics are numbered starting from one at the imine attachment point. The numbers associated with the substituents may therefore
be different from those used for the systematic name of the original fluroaromatic.
Ta ble 2. F lu or in e-19 NMRa Da ta a n d IRb Da ta for
groups, and the two imine N atoms are almost coplanar
with the fluoroaromatic ring. One of the phenyl rings
Com p ou n d s 1-6
on each of the PV centers is oriented approximately
parallel to the fluoroaromatic ring (dihedral angles of
5.79 and 0.42°), and one of the phenyl rings on each of
the PIII centers lies parallel to the fluoroaromatic ring
and is arranged above and below the fluoroaromatic ring
to form a sandwich of the fluoroaromatic ring with an
eclipsed orientation (dihedral angles of 4.73 and 5.98°).
In structure 2, similar features are observed, and the
dihedral angle is 3.7°. This eclipsed orientational
structure is not uncommon in these molecular systems;
similar relationships were previously observed in 4-(CN)-
C6F4NdP(Ph)2CH2PPh2 (where the dihedral angle is
19°) and 5-F-2,4-(NO2)2C6H2NdP(Ph)2CH2PPh2 (where
the dihedral angle is 8°).2
5J FF
(Hz) (cm-1
νCO
νCN
compd
δ(F)c (ppm)
J FP (Hz)
)
(cm-1
)
4
5
V
1
F2, -109.0 (dt);
F1, -140.7 (dt)
F2, -128.9
(a broad doublet);
F1, -138.9 (ddd)
J F1-P ) 14.0, 11.0
2205
2214
V
J F2-P ) 5.0
2
3
4J F1-P1 ) 14.3d, 11.3
4
V
J F1-P2 ) 13.8,
5J F2-P1 ) 5.0,
5
V
J F2-P2 ) 4.7
F2, -108.9 (ddd);
F1, -141.5 (dddd)
4J F1-P1 ) 14.6d, 11.3
2214
2217
4
V
J F1-P2 ) 13.9,
5J F2-P1 ) 5.0,
5
V
J F2-P2 ) 4.4,
4
III
J F1-P ) 2.6
4
F2, -111.6 (dd);
4J F1-P1 ) 6.8d, 11.3 1970
4
V
F1, -141.5 (broad) J F1-P2 ) 11.7,
5J F2-P1 ) 6.8,
5
V
J F2-P2 ) 4.8
5
6
F2, -106.4 (d);
F1, -119.2
(broad doublet)
F2, -108.2 (dt);
F1, -136.4 (m)
11.3 1977
2227
2216
The X-ray crystallographic data for 1 and 2 further
illuminate the nature of the P-N bond in the phospho-
ranimines, which is a polar, short bond of order greater
than one.4,5 Thus the P-N bond lengths in 1, 1.569(4)
and 1.581(3) Å, and in 2, 1.585(4) Å (in the PCPN group)
and 1.578(4) Å (in the Ph3PdN group), are within the
range of values for covalent radii (1.64 Å)6 for a double
bond and are comparable to those obtained for [N(P-
Ph3)2]+ (1.60 Å),7 Ph2FPdNMe (1.641 Å),8 and Ph3PdN-
C6H4-p-Br (1.56 Å).9 The PdN bond lengths observed
in our compounds are however significantantly longer
than that in the prototypical precursor Me3SiNdP-
(Ph)2CH2PPh2 (1.529(3) Å)10 following the general trend
of longer PdN bonds and narrower P-N-X angles for
those iminophophoranes which carry organic substi-
tutents (even those which are highly electron withdraw-
ing) in contrast to those which have silyl substitutents.11
6
III
J F1-P ) 3.24, 12.0 1972
5
5
V
J F1-P ) 8.92,
V
J F2-P ) 5.0
a
Spectra obtained in CDCl3 solution; ppm vs CFCl3. Positive
values indicate resonance to low field of standard. b All IR samples
d
were run in CH2Cl2. c F2 are adjacent to CN groups. P1 is in the
unit of PPh3 or PPh2Me.
The identification and molecular constitution of all
the compounds follows from the analytical data, mass
1
spectra, and H, 31P, and 19F NMR spectroscopy. Mo-
lecular ions for each of the compounds were observed
in the mass spectra. Phosphorus-31 NMR data are
given in Table 1, and the fluorine-19 NMR data are
given in Table 2. The identity of chemical shifts for both
PIII and both PV atoms in compound 1 indicated that
the two PCPN groups are related by symmetry. How-
ever when different phosphine imines are bound, the
different environments are readily distinguished by
their different chemical shifts. Compounds 1-3 also
Com p lexa tion Rea ction s of 1 a n d 2 w ith [Rh -
(CO)2Cl]2. Compound 2 reacts with 0.5 equiv of
[Rh(CO)2Cl]2 in CH2Cl2 at 25 °C to give complex 4 in
high yield (Scheme 3).
The 31P NMR chemical shifts of the PIII and PV centers
in complex 4 are very similar to those found earlier for
2
show characteristic J PP values which are about 5 Hz
smaller than those obtained for analogous monosubsti-
tuted species.2
The crystal and molecular structures for 1 and 2 have
been determined by X-ray diffraction as representative
examples of these new ligands. The ORTEP3 plots for
1 and 2 are shown in Figures 1 and 2, respectively.
The X-ray crystallographic data and the selected
bonding parameters for these ligands are given in
Tables 3-6 and in the Supporting Information. The
structure of 1 shows considerable internal molecular
regularity. The two remaining F atoms, the two CN
(4) Sudhakar, P. V.; Lammertsma, K. J . Am. Chem. Soc. 1991, 113,
1899.
(5) J ohnson, A. W. Ylides and Imides of Phosphorus; Wiley: New
York, 1993.
(6) Pauling, L. The Nature of the Chemical Bond, 3rd ed.; Cornell
Univ Press: Ithaca, NY, 1960.
(7) Canziani, F.; Garlaschelli, L.; Malatesta, M. C.; Albinati, A. J .
Chem. Soc., Dalton Trans. 1981, 2395.
(8) Adamson, G. W.; Bart, J . C. J . J . Chem. Soc. A 1970, 1452.
(9) Cameron, A. F.; Hair, N. S.; Norris, D. G. Acta Crystallog., Sect.
B 1974, 30, 221.
(10) Schmidbaur, H.; Bowmaker, G. A.; Kumberger, O.; Mu¨ller, G.;
Wolfsberger, W. Z. Naturforsch. B 1990, 45b, 476.
(11) Cavell, R. G.; Reed, R. W. Unpublished data.
(3) J ohnson, C. K. ORTEP, Report ORNL No. 5138, Oak Ridge
National Laboratory, Oak Ridge, TN, 1976.

1036 Organometallics, Vol. 15, No. 3, 1996
Ta ble 3. Su m m a r y of Cr ysta llogr a p h ic Da ta for Com p ou n d s 1, 2 a n d 5
Li et al.
compd
1
2
5
formula
fw
C62H50F2N6P4
1040.96
C53H40F2N5P3
877.86
C62H47Cl2F2N5O2P4Rh2
1332.71
cryst size (mm)
cryst system
space group
unit cell params
a (Å)
0.39 × 0.35 × 0.21
0.71 × 0.43 × 0.13
monoclinic
P21/na
0.27 × 0.23 × 0.15
triclinic
monoclinic
P1h (No. 2)
C2/c (No. 15)
10.6203(6)
14.2626(6)
20.0527(8)
79.577(4)
77.371(4)
68.886(4)
2747.5 (2)
2
14.101(2)
10.209(1)
31.845(3)
25.158(9)
16.379(2)
18.723(6)
b (Å)
c (Å)
R (deg)
â (deg)
99.38(1)
125.63(2)
γ (deg)
V (Å3)
4523 (1)
4
1.289
0.177
6271 (7)
4
1.412
0.753
Enraf-Nonius CAD4
Mo KR (0.710 73)
-50
θ-2θ
50.0
Z
Fcalcd (g cm-3
)
1.258
1.686
µ (mm-1
)
diffractometer
radiation (λ (Å))
temp (°C)
Siemens P4/RA
Cu KR (1.541 78)
-60
θ-2θ
100.0
6823
5635
4473b
Enraf-Nonius CAD4
Mo KR (0.710 73)
-50
scan type
ω
max 2θ (deg)
tot. data collcd
indpdt reflcns (NR)
observns (NO)
structure solution method
refinement method
abs corr method
range of abs corr factors
params (NV)
goodness-of-fit (S)
final R indicesj
R1
50.0
8563
5852
8346
5710
3097c
1950c
direct methodsd
full-matrix on F2 e
DIFABSg
1.348-0.805
667
direct methodsd
full-matrix on Ff
DIFABSg
1.084-0.731
343
direct methodsd
full-matrix on Ff
DIFABSg
1.251-0.764
234
1.053h
1.753i
1.549i
0.0526b
0.064c
0.071c
0.064c
0.067c
R2
wR2
0.1426k
A nonstandard setting of P21/c (No. 14). I g 2σ(I). c I g 3σ(I). Sheldrick, G. M. Acta Crystallogr. 1990, A46, 467. e Sheldrick, G. M.
a
b
d
J . Appl. Crystallogr. Manuscript in preparation. Refinement on Fo for all reflections (all of these having Fo < -3σ(Fo2)). R-factors
2
2
based on Fo are statistically about twice as large as those based on Fo, and R-factors based on all data will be even larger. f Structure
2
g
Determination Package, version 3; Enraf-Nonius: Delft, The Netherlands, 1985. Walker, N.; Stuart, D. Acta Crystallogr. 1983, A39,
h
2
i
158. S ) [∑w2(Fo - Fc2)2/(NR - NV)]1/2 (w2 ) [σ2(Fo2) + (0.0677P)2 + 2.8559P]-1, where P ) [max(Fo2,0) + 2Fc2]/3). S ) [∑w1(|Fo| -
j
2
|Fc|)2/(NO - NV)]1/2 (w1 ) 4Fo2/σ2(Fo2)). R1 ) ∑||Fo| - |Fc||/Σ|Fo|; R2 ) [Σw1(|Fo| - |Fc|)2/Σw1Fo
]
1/2; wR2 ) [Σw2(Fo2 - Fc2)2/Σw2(Fo4)]1/2.k On
all data.
Ta ble 4. Selected Bon d Dista n ces (Å) in
Com p ou n d s 1, 2 a n d 5
Ta ble 5. Selected Bon d An gles (d eg) in
Com p ou n d 1a
1
2
5
N(1)-P(1)-C(11)
N(1)-P(1)-C(21)
C(9)-P(1)-C(11)
C(9)-P(1)-C(21)
C(11)-P(1)-C(21)
C(9)-P(2)-C(31)
C(9)-P(2)-C(41)
C(31)-P(2)-C(41)
N(2)-P(3)-C(10)
N(2)-P(3)-C(51)
N(2)-P(3)-C(61)
C(10)-P(3)-C(51)
C(10)-P(3)-C(61)
C(51)-P(3)-C(61)
C(10)-P(4)-C(71)
C(10)-P(4)-C(81)
C(71)-P(4)-C(81)
P(1)-N(1)-C(6)
P(3)-N(2)-C(2)
F(1)-C(1)-C(2)
N(1)-C(2)-C(1)
N(1)-C(2)-C(3)
F(2)-C(4)-C(5)
N(2)-C(6)-C(1)
N(2)-C(6)-C(5)
105.4(2)
115.8(2)
106.4(2)
108.7(2)
103.5(2)
101.3(2)
102.1(2)
100.9(2)
116.4(2)
114.3(2)
105.0(2)
109.2(2)
106.3(2)
104.5(2)
102.0(2)
101.6(2)
101.7(2)
132.1(3)
133.2(3)
116.8(3)
127.5(4)
116.8(4)
118.6(4)
127.5(4)
118.0(4)
N(3)-C(7)-C(3)
N(4)-C(8)-C(5)
P(1)-C(9)-P(2)
179.2(5)
178.8(5)
110.2(2)
110.7(2)
121.0(3)
119.6(3)
116.4(3)
125.4(3)
127.0(4)
115.3(4)
117.2(4)
124.4(4)
125.4(3)
116.1(3)
121.1(4)
118.4(4)
118.3(4)
123.8(4)
125.8(4)
115.8(4)
119.3(4)
121.8(4)
121.0(4)
118.6(4)
P(1)-N(1) 1.581(3) P(1)-C(9) 1.860(5) Rh-Cl
P(1)-C(9) 1.805(4) P(1)-C(11) 1.826(5) Rh-P(2)
P(1)-C(11) 1.802(4) P(1)-C(21) 1.831(6) Rh-N(1)
P(1)-C(21) 1.797(4) P(2)-N(1) 1.585(4) Rh-C(6)
2.361(4)
2.206(4)
2.153(8)
1.426(3)
P(3)-C(10)-P(4)
P(1)-C(11)-C(12)
P(1)-C(11)-C(16)
P(1)-C(21)-C(22)
P(1)-C(21)-C(26)
P(2)-C(31)-C(32)
P(2)-C(31)-C(36)
P(2)-C(41)-C(42)
P(2)-C(41)-C(46)
P(3)-C(51)-C(56)
P(3)-C(51)-C(52)
P(3)-C(61)-C(62)
P(3)-C(61)-C(66)
P(4)-C(71)-C(76)
P(4)-C(71)-C(72)
P(4)-C(81)-C(86)
P(4)-C(81)-C(82)
C(2)-C(3)-C(7)
C(4)-C(3)-C(7)
C(4)-C(5)-C(8)
C(6)-C(5)-C(8)
P(2)-C(9) 1.853(4) P(2)-C(9) 1.807(5) P(1)-N(1) 1.61(1)
P(2)-C(31) 1.833(5) P(2)-C(31) 1.787(5) P(1)-C(7) 1.78(1)
P(2)-C(41) 1.839(5) P(2)-C(41) 1.802(5) P(1)-C(11) 1.77(1)
P(3)-N(2) 1.569(4) P(3)-N(2) 1.578(4) P(1)-C(21) 1.81(1)
P(3)-C(10) 1.801(4) P(3)-C(51) 1.803(5) P(2)-C(7) 1.78(1)
P(3)-C(51) 1.806(4) P(3)-C(61) 1.797(5) P(2)-C(31) 1.79(1)
P(3)-C(61) 1.805(4) P(3)-C(71) 1.798(6) P(2)-C(41) 1.81(1)
P(4)-C(10) 1.858(4) F(1)-C(1) 1.377(5) F(1)-C(1) 1.36(2)
P(4)-C(71) 1.828(5) F(2)-C(4) 1.373(6) F(2)-C(4) 1.35(2)
P(4)-C(81) 1.827(5) N(1)-C(2) 1.351(6) O-C(6)
1.12(1)
F(1)-C(1) 1.366(4) N(2)-C(6) 1.364(6) N(1)-C(2) 1.40(1)
F(2)-C(4) 1.354(5) N(3)-C(7) 1.143(6) N(2)-C(5) 1.12(1)
N(1)-C(6) 1.358(5) N(4)-C(8) 1.149(7) C(3)-C(5) 1.46(2)
N(2)-C(2) 1.356(5) C(3)-C(7) 1.448(7)
N(3)-C(8) 1.140(6) C(5)-C(8) 1.414(8)
N(4)-C(7) 1.140(6)
C(3)-C(7) 1.429(7)
C(5)-C(8) 1.435(7)
a
Numbers in parentheses are estimated standard deviations
in the least significant digits.
a
Numbers in parentheses are estimated standard deviations
in the least significant digits.
the complexes RNdP(Ph)2CH2P(Ph)2Rh(CO)Cl,2,12 in
which the imine nitrogen carries fluoroaromatic or
dinitro substituents (R); however, in 4, the signal arising
from the uncomplexed Ph3PdN unit is shifted to low
field by about 3.5 ppm suggesting some additional
(12) Cavell, R. G.; Katti, K. V. Unpublished data.

Fluoroaromatic Bis(phosphinimine) Ligands
Organometallics, Vol. 15, No. 3, 1996 1037
Ta ble 6. Selected Bon d An gles (d eg) in
Com p ou n d 2a
Sch em e 4
C(9)-P(1)-C(11)
C(9)-P(1)-C(21)
C(11)-P(1)-C(21)
N(1)-P(2)-C(9)
N(1)-P(2)-C(31)
N(1)-P(2)-C(41)
C(9)-P(2)-C(31)
C(9)-P(2)-C(41)
C(31)-P(2)-C(41)
N(2)-P(3)-C(51)
N(2)-P(3)-C(61)
N(2)-P(3)-C(71)
C(51)-P(3)-C(61)
C(51)-P(3)-C(71)
C(61)-P(3)-C(71)
P(2)-N(1)-C(2)
P(3)-N(2)-C(6)
F(1)-C(1)-C(2)
F(1)-C(1)-C(6)
N(1)-C(2)-C(1)
N(1)-C(2)-C(3)
F(2)-C(4)-C(3)
F(2)-C(4)-C(5)
101.3(2)
100.6(2)
99.2(2)
N(2)-C(6)-C(1)
N(2)-C(6)-C(5)
N(3)-C(7)-C(3)
N(4)-C(8)-C(5)
P(1)-C(9)-P(2)
127.4(5)
116.3(5)
177.6(7)
178.9(7)
110.5(3)
123.4(4)
119.5(4)
114.6(5)
126.9(5)
122.0(4)
118.9(4)
114.9(4)
124.2(4)
125.4(4)
115.5(4)
120.4(4)
120.3(4)
115.9(5)
124.4(5)
119.5(5)
120.6(5)
121.9(5)
121.1(5)
115.5(3)
106.1(3)
114.7(3)
104.5(2)
109.3(2)
105.7(2)
116.0(2)
104.5(3)
116.8(3)
104.7(2)
108.5(3)
105.0(3)
129.9(4)
134.7(4)
116.2(5)
116.1(4)
128.8(5)
117.4(5)
117.8(5)
116.9(5)
P(1)-C(11)-C(12)
P(1)-C(11)-C(16)
P(1)-C(21)-C(22)
P(1)-C(21)-C(26)
P(2)-C(31)-C(32)
P(2)-C(31)-C(36)
P(2)-C(41)-C(42)
P(2)-C(41)-C(46)
P(3)-C(51)-C(52)
P(3)-C(51)-C(56)
P(3)-C(61)-C(62)
P(3)-C(61)-C(66)
P(3)-C(71)-C(72)
P(3)-C(71)-C(76)
C(2)-C(3)-C(7)
C(4)-C(3)-C(7)
C(4)-C(5)-C(8)
C(6)-C(5)-C(8)
a
Numbers in parentheses are estimated standard deviations
in the least significant digits.
Sch em e 3
PV centers, and the observed low-field shift probably
reflects the deshielding by this phenyl group environ-
ment. Similar behavior was also observed in complex
4. In that case, the 19F chemical shifts of the fluorine
atom which is located ortho to the PV were shifted by
16 ppm to low field suggesting that one of the phenyl
substituents on PV lies physically close to this fluorine.
The CO stretching frequency of 5 is 1979 cm-1, consis-
electron delocalization from the fluoroaromatic ring in
this complex. Direct PIII-Rh bonding is clearly indi-
1
cated by the large characteristic J PRh value. The νCO
value of 1970 cm-1 (Table 2) indicates that the CO group
coordinated to Rh is located cis to the PIII center.
Compound 1 reacts with 1 molar equiv of [Rh(CO)2-
Cl]2 to give the dimetallic complex 5 (Scheme 4) in which
both coordination sites are occupied.
1
tent with a cis phosphine-carbonyl structure. The H
NMR spectrum in the CH2 region showed two signals
implying two inequivalent environments for the hydro-
gens of each methylene group.
Reacting 1 with 0.5 equiv of [Rh(CO)2Cl]2 gives
complex 6 in which only one Rh atom is complexed by
the ligand (Scheme 4), and in turn, another 1 equiv of
Rh precursor at room temperature in CH2Cl2 gives the
fully metalated product 5. The process can be reversed
in that treating 5 with more ligand 1, again at room
temperature in CH2Cl2, produces the half-metalated
product 6.
The molecular structure of 5 was obtained by X-ray
diffraction, and the ORTEP3 plot is shown in Figure 3.
The structural parameters for 5 and the bonding
parameters are given in Tables 3, 4, and 7 and in
Supporting Information. The structure comprises the
neutral dimeric complex 4,6-(CN)2C6F2-1,3-bis(NdP(Ph)2-
The NMR data of 5 showed that the two Rh centers
are equivalent with 31P chemical shifts of the PV and
PIII centers being similar to those of the monosubsti-
tuted analogs. The PIII signal is strongly shifted (by 68
ppm) to low field upon coordination, and the PV signal,
a broad poorly resolved doublet, is similarly shifted (by
32 ppm) relative to the free ligand. The fluorine located
between the two CN groups in 5 shows no substantial
change in the NMR chemical shift upon complexation
of the ligand to the metal, but the fluorine located
between the imine nitrogens is shifted by 22 ppm to low
field upon complex formation. The crystal structure
(vide infra) shows that this fluorine is located very close
to two of the phenyl groups, one from each of the two
CH2P(Ph)2Rh(CO)Cl), 5, with a cocrystallized molecule
of CH3CN. The complex shows a square planar geom-
etry around each Rh(I) with the CO cis to the phosphine
as indicated by the IR spectrum. Bond angles and
lengths are typical for a square planar chelate of Rh(I).
The P(1)-N(1) distance of 1.61(1) Å in the complex is
within the range found for a coordinated iminophos-
phoranyl group.2 The directly bound Rh-PIII distance
of 2.206(4) Å also lies within the range found in many
Rh(I) phosphine complexes of the type P2Rh(CO)Cl.13-19
(13) Bennett, M. J .; Donaldson, P. B. J . Am. Chem. Soc. 1971, 93,
3307.

1038 Organometallics, Vol. 15, No. 3, 1996
Li et al.
the lower structure of Figure 3 clearly shows that one
Rh lies below and the other lies above the fluoroaromatic
ring. The dihedral angle between the Rh-P(2)-C(7)-
N(1) plane and the fluoroaromatic ring is 76.0°.
Compared with our previously described Rh com-
plexes,2,20,21 and the above described disubstituted
complex, this Rh complex was unusual. First, 31P NMR
data indicate that the two PCPN groups are sym-
metrically coordinated to Rh; therefore, we surmise that
the two PIII units must be coordinated to the Rh metal
center and that they must be in a mutual trans
relationship. The presence of a large coupling in the
PIII unit due to 1J PRh readily identifies the 31P chemical
shift of PIII showing that this signal lies to lower field
than that of PV. Thus the PIII has shifted by about 54
ppm to low field upon coordination (as in 5 and 4)
whereas the PV signal shifts instead to high field by
1
about 10 ppm. The J PRh value of 128.6 Hz (obtained
by analysis of the second-order spectrum) is also smaller
than usual. For the 19F NMR spectrum, the fluorine
which lies between the two PV imines is not as greatly
affected as was the case in 5 and has only been shifted
by 4 ppm to low field upon complexation. This suggests
that in this case the phenyl rings subtended on PV are
not proximate to this fluorine as was the case with 4.
The spectral pattern is a doublet of triplets of triplets,
which indicates coupling to the other fluorine, two PV
and two PIII, respectively. The other fluorine is a
doublet of triplets, clearly arising from the coupling to
one other fluorine and to two PV but not to the remote
PIII. The 31P NMR spectrum was clearly second order
and showed complex multiplets for both PIII and PV
signals. The spectral pattern for 6 is illustrated in
Figure 4 (top). A large coupling between Rh and PIII is
readily observed which clearly identifies this low-field
signal as that arising from the PIII center. The PV signal
is therefore the higher field signal which contrasts to
related compounds in the system but which is consistent
with the proposed formulation. In this case the imine
N of the PCPN unit is not coordinated to the Rh center
and so the PV signal is not substantially shifted by
coordination. The coupling patterns cannot be clearly
F igu r e 3. Top: Perspective views of 5 showing the atom-
labeling scheme. Non-hydrogen atoms are represented by
Gaussian ellipsoids at the 20% probability level. The dppm
methylene hydrogens are shown artificially small, while
those of the phosphine phenyl groups are not shown.
Bottom: Top view of the molecule.
Ta ble 7. Selected Bon d An gles (d eg) in
Com p ou n d 5a
Cl-Rh-P(2)
174.7(1)
87.8(3)
95.2(4)
87.7(3)
89.4(4)
Rh-N(1)-C(2)
123.4(8)
123.0(8)
117.6(9)
124(1)
119(1)
121(1)
121(1)
117.9(8)
176(2)
Cl-Rh-N(1)
P(1)-N(1)-C(2)
F(1)-C(1)-C(2)
N(1)-C(2)-C(1)
N(1)-C(2)-C(3)
C(2)-C(3)-C(5)
C(4)-C(3)-C(5)
F(2)-C(4)-C(3)
N(2)-C(5)-C(3)
Rh-C(6)-O
Cl-Rh-C(6)
P(2)-Rh-N(1)
P(2)-Rh-C(6)
N(1)-Rh-C(6)
N(1)-P(1)-C(7)
N(1)-P(1)-C(11)
N(1)-P(1)-C(21)
C(7)-P(1)-C(11)
C(7)-P(1)-C(21)
C(11)-P(1)-C(21)
Rh-P(2)-C(7)
Rh-P(2)-C(31)
Rh-P(2)-C(41)
C(7)-P(2)-C(31)
C(7)-P(2)-C(41)
C(31)-P(2)-C(41)
Rh-N(1)-P(1)
176.4(5)
101.8(5)
113.2(5)
114.6(6)
110.7(6)
106.2(5)
109.9(5)
105.4(4)
116.4(4)
120.3(4)
108.3(5)
102.6(6)
102.6(6)
111.2(5)
178(1)
P(1)-C(7)-P(2)
P(1)-C(11)-C(12)
P(1)-C(11)-C(16)
P(1)-C(21)-C(22)
P(1)-C(21)-C(26)
P(2)-C(31)-C(32)
P(2)-C(31)-C(36)
P(2)-C(41)-C(42)
P(2)-C(41)-C(46)
108.5(6)
118.9(9)
124(1)
119(1)
121(1)
121(1)
122.3(9)
123(1)
extracted even in spite of substantial but obscure PIII
-
PV coupling which is usually a clearly defined feature
in spectra of compounds of this type. Homonuclear 31P-
{31P} NMR decoupling measurements (Figure 4, bottom)
applied to PV reduced the PIII pattern to a doublet of
doublets, the smaller doublet probably arising from the
coupling of F1 with PIII. Applied to PIII, homonuclear
decoupling reduces the PV pattern to a doublet of
doublets which indicates that PV couples to two different
fluorines (Figure 4, bottom). These experiments in
themselves did not provide sufficient information to fully
determine the coupling interactions between PIII and PV.
The pattern of the spectrum was however successfully
simulated (Figure 4, middle)22 with the fit shown. The
successful spectral simulation suggests that the two PIII
centers and likewise the two PV centers are each
120(1)
a
Numbers in parentheses are estimated standard deviations
in the least significant digits.
The molecule has C2 symmetry with the two fluorine
atoms and the carbons to which they are attached being
located on a crystallographic 2-fold axis. These two F
atoms, the two CN groups, and two imine N atoms are
coplanar with the fluoroaromatic ring. The Cl, Rh, C(6),
O, N(1), P(2) and C(7) atoms are almost coplanar, while
P(1) lies significantly above the plane, by 0.722 Å. The
dihedral angle between the Rh-P(2)-C(7)-N(1) and
C(7)-P(1)-N(1) planes is 133.3°. The view shown in
(20) Katti, K. V.; Cavell, R. G. Organometallics 1988, 7, 2236.
(21) Katti, K. V.; Cavell, R. G. Organometallics 1989, 8, 2147.
(22) NMR spectral simulations were carried out with the Bruker
Instrument Co. spectral analysis program, PANIC (parameter adjust-
(14) Bennett, M. J .; Donaldson, P. B. Inorg. Chem. 1977, 16, 1581.
(15) Bennett, M. J .; Donaldson, P. B. Inorg. Chem. 1977, 16, 1585.
(16) Bennett, M. J .; Donaldson, P. B. Inorg. Chem. 1977, 16, 655.
(17) Bonnet, J . J .; Kalck, P.; Poilblanc, R. Inorg. Chem. 1977, 16,
1514.
(18) Kessler, J . M.; Nelson, J . H.; Frye, J . S.; DeCian, A.; Fischer,
J . Inorg. Chem. 1993, 32, 1048.
ment in NMR by iteration calculation). The simulated 31P NMR
1
spectrum parameters for compound 6 are as follows: J P(A)-Rh
)
)
)
)
1J P(A′)-Rh ) 128.5 Hz, J P(A)-P(B)
)
)
)
2J P(A′)-P(B′) ) 1.85 Hz, J P(A)-P(B′)
2
4
4J P(A′)-P(B) ) 1.75 Hz, J P(A)-F(A)
6J P(A′)-F(A) ) 3.24 Hz, J P(B)-F(A)
6
4
5
5
(19) Osakada, K.; Hataya, K.; Yamamoto, T. Inorg. Chem. 1993, 32,
2360.
4J P(B′)-F(A) ) 8.92 Hz, J P(B)-F(B)
5J P(B′)-F(B) ) 5.00 Hz, J F(A)-F(B)
12.00Hz.

Fluoroaromatic Bis(phosphinimine) Ligands
Organometallics, Vol. 15, No. 3, 1996 1039
Ta ble 8. νCN Sh ifts on Su bstitu tion
F
R1
R2
NC
CN
F
a
R1/R2
ν
CN (cm-1
)
∆ (cm-1
)
F/F
F/NdPPh3
F/NdP(Ph)2CH2PPh2
NdPPh3/NdPPh3
NdPPh3/NdP(Ph)2CH2PPh2
NdP(Ph)2CH2PPh2/
2252
2237
2231
2217
2214
2205
15
21
35
38
47
NdP(Ph)2CH2PPh2
a∆ ) (2252 - νCN) cm-1
.
be done within this structure as the resultant bicyclic
ring structure should not suffer extraordinary strain;
however, such experiments have not yet been at-
tempted.
The stretching frequencies of the CN groups in the
ligands are substantially reduced compared with those
displayed by the starting material, 1,3-(CN)2C6F4. These
data are compared with that from other related com-
pounds, such as 2,4-(CN)2C6F3NdPPh3,23 4,6-(CN)2C6F2-
1,3-bis(NdPPh3),23 and 2,4-(CN)2C6F3NdP(Ph)2CH2-
12
PPh2 (Table 8) The order of ∆, the difference in νCN
relative to the parent cyanobenzene, indicates that
reducing the electronegativity of the substituent (or
increasing the donor capability of the substituent) leads
to more electron delocalization with CN groups and
therefore a greater decrease of the CN stretching
frequencies. NdP(Ph)2CH2PPh2 is a better electron
donor than NdPPh3.
The influences of R1 and R2 on νCN are roughly
additive. When R1 ) F, R2 ) (NdPPh3), a decrease of
15 cm-1 for νCO is observed whereas when R1 ) R2 )
(NdPPh3), the decrease is 35 cm-1, which is slightly
more than twice the value of the former. When R1 )
F, R2 ) (NdP(Ph)2CH2PPh2), a decrease of 21 cm-1 is
observed whereas when R1 ) R2 ) (NdP(Ph)2CH2PPh2),
the decrease is 47 cm-1, which again is slightly more
than twice the value of the former. In the case of R1 )
(NdPPh3), R2 ) (NdP(Ph)2CH2PPh2), a decrease of 38
cm-1 is observed, and this value is only slightly greater
than the sum of the individual contribution of the two
groups. Dividing these shift decrements into compo-
nents due to each group gives an approximate decre-
ment of 16-18 cm-1 for a NdPPh3 group and approxi-
mately 24 cm-1 for the diphosphorus substituent relative
to the original fluorine substituent.
Many complexes are known which contain uncoordi-
nated CN groups, and there is no systematic shift of
the CN stretching frequency; the value in the complex
may be either higher or lower than that shown by the
corresponding ligand.24 We observe herein that the
stretching frequencies of the uncoordinated CN groups
in our metal complexes are in all cases higher than that
of the corresponding vibration in the uncomplexed
ligands (Table 2). Some shifts are very small; e.g. in
the complex 4, νCN ) 2217 cm-1, whereas, in ligand 2,
νCN ) 2214 cm-1, an increase of only 3 cm-1 upon
F igu r e 4. 31P NMR spectra of 6: (top) experimental
spectrum; (center) simulated spectrum; Bottom: spectrum
with homonuclear 31P{31P} decoupling applied to PV and
PIII, respectively.
chemically equivalent but the magnetical inequivalence
leads to second order behavior. The coupling constants
2
2
extracted from the simulation, J P(A)-P(B) ) J P(A′)-P(B′)
4
4
) 1.85 Hz and J P(A)-P(B′) ) J P(A′)-P(B) ) 1.75 Hz show
only a very small difference (0.10 Hz) between each
other, but we feel that the values are reliable because
small changes in these coupling constant values make
a big difference in the calculated spectral pattern and
destroy the match with the experimental spectrum.
The 1H NMR spectrum of the CH2 region of 6, similar
to that for 5, showed two different signals, each one
showing a doublet of doublet of doublets pattern. The
two hydrogens on each methylene carbon therefore have
different magnetic environments; each hydrogen is
therefore coupled to the other hydrogen on the CH2
bridge and to two different phosphorus centers.
The NMR spectral behavior is therefore consistent
with the formulation of complex 6 as a bis(phosphine)
complex of Rh(I) in which the long arms of the ligand 1
are able to span the trans positions of the square plane
to form a 12-membered macrocyclic ring. This is favored
by the affinity of Rh(I) for a PIII donor. It would be
interesting to see if internal coupling reactions could
(23) Li,J .; Cavell, R. G. Manuscript in preparation.
(24) Storhoff, B. N.; Lewis, H. C., J r. Coord. Chem. Rev. 1977, 23,
1.

1040 Organometallics, Vol. 15, No. 3, 1996
Li et al.
before the solvent was removed in vacuo to leave a yellow
crystalline solid. This crude product was recrystallized from
acetonitrile to obtain the pure compound 1 (yield 0.32 g; 39%;
cubic crystals, suitable for diffraction studies; mp 292 °C).
Anal. Calcd for C58H44N4F2P2: C, 72.65; H, 4.62; N, 5.84.
Found: C, 72.37; H, 4.50; N, 5.85. MS (FAB, m/z): 959 (M+,
100%). 1H NMR (CDCl3): phenyl rings δ 7.05, 7.15, 7.30, 7.42,
coordination. The small shift indicates that the CN
substituent environment is not greatly perturbed by
coordination in this case. In contrast, for complex 5,
νCN )2227 cm-1, an increase of 22 cm-1 upon complex-
ation vs ligand 1 (νCN ) 2205 cm-1). Similarly the
monometallic complex 6 (νCN ) 2216 cm-1) shows an
increase of νCN relative to the ligand of 11 cm-1 which
is just a half as large as the coordination shift in the
bimetallic complex 5. The difference between CN bond
lengths in ligand 1 (1.140(6) Å) and in the metal complex
5 (1.12(1) Å) is not sufficiently great to indicate any
trends or correlations between stretching frequency and
bond length and strength.
7.75 (m, 40H); PCH2P methylene δ 2.77 (dd, 2H, 2J HP ) 12.40
V
2
III
Hz, J HP ) 2.30 Hz).
Syn th esis of 4,6-(CN)2C6F 2-1-(NdP (P h )2CH2P (P h )2)-3-
(NdP P h 3) (2). To a solution of Me3SiNdP(Ph)2CH2PPh2 (0.31
g; 0.66 mmol) in dry toluene (20 mL) was added dropwise a
23
solution of 2,4-(CN)2C6F3NdPPh3 (0.30 g; 0.66 mmol) also
in toluene (50 mL). The reaction mixture was refluxed for 12
h before the solvent was removed in vacuo to leave a light
yellow crystalline solid. This crude product was recrystallized
from acetonitrile to obtain the pure compound 2 (yield 0.52 g;
95%; cubic crystals, suitable for diffraction studies; mp 231
°C). Anal. Calcd for C51H37N4F2P3: C, 73.20; H, 4.47; N, 6.70.
Found: C, 72.67; H, 4.37; N, 6.74. MS (EI, m/z): 836 (M+,
100%). 1H NMR (CDCl3): phenyl rings δ 7.10, 7.35, 7.55 (m,
Con clu sion s
Active fluorine atoms at the 4 and 6 positions, each
para to the CN groups in 1,3-dicyanotetrafluorobenzene,
can be substituted by an iminophosphorane unit; thus,
mono- and disubstituted phosphorano-phosphinimine
fluoroaromatic compounds can be obtained. The reac-
tions proceed smoothly and can be carried out sequen-
tially to yield complex bidentate phosphorano-phos-
phines. These multifunctional ligands readily react
with [Rh(CO)2Cl]2 to form mono- and dimetallic Rh(I)
complexes which exhibit either P-N chelate or P-P
bidentate macrocyclic coordination. The dimetallic
complex shows a square plannar geometry around each
Rh(I) with the CO cis to the phosphine. The whole
molecule has C2 symmetry with the two fluorine atoms
on a 2-fold axis. The structure of a P-P bidentate
macrocyclic complex was deduced as a bis(phosphine)
chelate from the complex second-order 31P NMR spec-
trum solved by simulation. The two PIII centers are
trans coordinated to the Rh center, and the two N atoms
are not coordinated.
2
V
35H), PCH2P methylene δ 2.83 (dd, 2H, J HP ) 12.50 Hz,
2
III
J HP ) 2.30 Hz).
Syn t h esis of 4,6-(CN)2C6F 2-1-(NdP P h 2CH 2P P h 2)-3-
(NdP P h 2Me) (3). To a solution of Me3SiNdPPh2CH2PPh2
(0.30 g; 0.63 mmol) in dry toluene (20 mL) was added dropwise
a solution of 2,4-(CN)2C6F3NdPPh2Me23 (0.25 g; 0.63 mmol)
also in toluene (60 mL). The reaction mixture was refluxed
for 12 h before the solvent was removed in vacuo to leave a
light yellow crystalline solid. This crude product was recrys-
tallized from acetonitrile to obtain the pure compound 3 (yield
0.35 g; 74%; colorless cubic crystals, suitable for diffraction
studies; mp 241 °C). Anal. Calcd for C46H35N4F2P3: C, 71.32;
H, 4.55; N, 7.23. Found: C, 71.09; H, 4.56; N, 7.47. MS (EI,
m/z): 775 (M+, 100%). 1H NMR (CDCl3): phenyl rings δ 7.15,
7.28, 7.45, 7.70 (m, 20H), methyl group δ 1.63 (dd, 3H). PCH2P
2
2
V
III
methylene δ 2.91 (dd, 2H, J HP ) 12.40 Hz, J HP ) 2.50 Hz).
Syn th esis of 4,6-(CN)2C6F2-3-(NdP P h 3)-1-(NdP (P h )2CH2-
P (P h )2Rh (CO)Cl) (4). To a solution of [Rh(CO)2Cl]2 (30.0 mg;
0.07714 mmol) in dry CH2Cl2 (15 mL) was added dropwise a
solution of 4,6-(CN)2C6F2-1-(NdP(Ph)2CH2PPh2)-3-(NdPPh3)
(2) (0.1291 g; 0.1543 mmol) also in CH2Cl2 (20 mL). The
reaction mixture was stirred at room temperature for 4 h
before the solvent was removed in vacuo to leave a yellow solid.
This crude product was recrystallized from CH2Cl2/hexane (2:
1) to obtain the pure compound 4 (yield 0.134 g; 87%; mp >
210 °C dec). Anal. Calcd for C52H37N4OClF2P3Rh: C, 62.26;
H, 3.72; N, 5.58; Cl, 3.53. Found: C, 62.23; H, 3.65; N, 5.60;
Cl, 3.96. MS (FAB, m/z): 1003 (M+, 100%). 1H NMR
(CDCl3): phenyl rings δ 7.25, 7.53, 7.68, 7.85 (m, 35H), PCH2P
Exp er im en ta l Section
All experimental manipulations were performed under
atmosphere of dry argon using Schlenk techniques. Solvents
were dried and distilled prior to use. Toluene, acetonitrile,
and dichloromethane were distilled from Na, CaH2, and P4O10
,
respectively. These solvents were purged with dry argon for
at least 0.5 h before use. Commercial (Aldrich) supplies of
dppm, Me3SiN3, 1,4-dicyanotetrafluorobenzene, 1,3-dicyan-
otetrafluorobenzene, and 1,2-dicyanotetrafluorobenzene were
used as obtained. Ph2PCH2P(Ph)2dNSiMe3 was prepared as
previously described.1 Nuclear magnetic resonance spectra
were recorded on Bruker WH-200 and 400 spectrometers with
reference to the deuterium signal of the solvent employed. The
1H chemical shifts are reported in ppm from external Me4Si,
the 31P NMR spectra are reported in ppm from external 85%
H3PO4, and the 19F NMR spectra are reported in ppm from
external CFCl3. Positive values reflect shifts downfield. Low-
resolution mass spectra were recorded at 16 or 70 eV on an
AEI MS50 spectrometer. Positive ion fast atom bombardment
mass spectra (FAB-MS) were recorded by using Xe fast atoms
on a customized AEI MS9 spectrometer. Infrared spectra were
recorded on a Nicolet 7199 infrared spectrometer. Melting
points were ascertained by visual methods in unsealed capil-
laries. Osmometry measurements were made in CH2Br2
solutions on a Corona Wescan vapor pressure osmometer by
the University of Alberta Microanalytical Services.
2
V
methylene δ 2.91 (d, 2H, J HP ) 12.00 Hz).
Syn t h esis of 4,6-(CN)2C6F 2-1,3-b is(NdP (P h )2CH 2P -
(P h )2Rh (CO)Cl) (5). Method A. To a solution of [Rh(CO)2Cl]2
(30.0 mg; 0.077 mmol) in dry CH2Cl2 (15 mL) was added
dropwise a solution of 4,6-(CN)2C6F2-1,3-bis(NdP(Ph)2CH2-
PPh2) (1) (0.0740 g; 0.077 mmol) also in CH2Cl2 (25 mL). The
reaction mixture was stirred at room temperature for 4 h
before the solvent was removed in vacuo to leave a yellow solid.
This crude product was recrystallized from CH2Cl2/hexane (2:
1) to obtain the dichloromethane solvate of 5 (yield 64.0 mg;
60%; mp 276-8 °C). Anal. Calcd for C61H46N4O2Cl4F2P4Rh2:
C, 53.22; H, 3.37; N, 4.07; Cl, 10.30. Found: C, 53.11; H, 3.24;
N, 4.06; Cl, 9.47. MS (FAB, m/z): 1255 ((M+ - Cl), 100%). No
peak at m/z 1292 (parent peak) was observed. 1H NMR
(CDCl3): phenyl rings δ 7.15, 7.30, 7.50, 7.80 (m, 40H), PCH2P
methylene δ 3.77 (m, 2H), δ 3.55 (m, 2H). Meth od B. To a
50 mL flask was added 10 mL of CH2Cl2, compound 6 (0.037
g, 0.0306 mmol), and [Rh(CO)2Cl]2 (0.001 g, 0.0153 mmol). The
mixture was stirred at room temperature for 5 h before the
Syn th esis of 4,6-(CN)2C6F 2-1,3-bis(NdP (P h )2CH2P P h 2)
(1). To a solution of Me3SiNdP(Ph)2CH2PPh2 (0.80 g; 1.70
mmol) in dry toluene (20 mL) was added dropwise a solution
of 1,3-dicyanotetrafluorobenzene (0.17 g; 0.85 mmol) also in
toluene (20 mL). The reaction mixture was refluxed for 12 h

Fluoroaromatic Bis(phosphinimine) Ligands
Organometallics, Vol. 15, No. 3, 1996 1041
solvent was removed in vacuo to leave 5 as a yellow solid
identified by 31P, and 19F NMR and IR data.
atoms. Final R values are given in Table 3, and final
difference peaks were small and without chemical significance.
Syn t h esis of 4,6-(CN)2C6F 2-1,3-b is(NdP (P h )2CH 2P -
(P h )2)Rh (CO)Cl (6). Meth od A. To a solution of [Rh(CO)2-
Cl]2 (30.0 mg; 0.077 mmol) in dry CH2Cl2 (15 mL) was added
dropwise a solution of 4,6-(CN)2C6F2-1,3-(NdP(Ph)2CH2P(Ph)2)2
(1) (0.1480 g; 0.154 mmol) also in CH2Cl2 (35 mL). The
reaction mixture was stirred at room temperature for 4 h
before the solvent was removed in vacuo to leave a yellow solid.
This crude product was recrystallized from CH2Cl2/hexane (2:
1) to obtain the dichloromethane solvates of 6 (yield 0.117 g;
63%; mp dec). Anal. Calcd for C60H46N4OCl3F2P4Rh: C, 59.55;
H, 3.83; N, 4.63; Cl, 8.79. Found: C, 59.55; H, 3.58; N, 4.69;
Cl, 8.80. MS (FAB, m/z): 1125 (M+, 100%). Molecular weight
determination: 1041. 1H NMR (CDCl3): phenyl rings δ 7.30,
7.57 (m, 40H), PCH2P methylene δ 3.38 (ddd, 2H), δ 5.35 (ddd,
2H). Meth od B. To a 50 mL flask was added 10 mL of CH2-
Cl2, compound 1 (0.012 g, 0.013 mmol), and compound 5 (0.017
g, 0.013 mmol). The mixture was stirred at room temperature
for 5 h before the solvent was removed in vacuo to leave a
yellow solid which was identified as 6 by 31P, and 19F NMR
and IR data.
Cr ysta llogr a p h y. Crystal structures of the compounds 1,
2, and 5 were done at the University of Alberta. The relevant
experimental collection and solution data are given in Table
3. In all cases the data collection and structure refinement
was straightforward. Direct methods were used to solve all
structures. The hydrogen atoms were generated at idealized
calculated positions by assuming a C-H bond length of 0.95
Å and the appropriate sp2 or sp3 geometry. All hydrogen atoms
were then included in the calculations with fixed, isotropic
Gaussian displacement parameters 1.2 times those of the
attached atoms and were constrained to “ride” on the attached
Ack n ow led gm en t. We thank the Natural Sciences
and Engineering Research Council of Canada and the
University of Alberta for financial support.
Su p p or tin g In for m a tion Ava ila ble: For 1, tables of
crystallographic experimental data (S1-1), atomic coordinates
and equivalent isotropic displacement parameters (S1-2),
selected interatomic distances (S1-3), selected interatomic
angles (S1-4), torsional angles (S1-5), least-squares planes (S1-
6), anisotropic displacement parameters (S1-7), and derived
atomic coordinates and displacement parameters for hydrogen
atoms (S1-8), for 2, tables of crystallographic experimental
data (S2-1), selected interatomic distances (S2-2), selected
interatomic angles (S2-3), torsional angles (S2-4), weighted
least-squares planes and dihedral angles (S2-5), atomic coor-
dinates and equivalent isotropic displacement parameters (S2-
6), anisotropic displacement parameters (S2-7), and derived
atomic coordinates and displacement parameters for hydrogen
atoms (S2-8), and for 5, tables of crystallographic experimental
data (S3-1), selected interatomic distances (S3-2), selected
interatomic angles (S3-3), torsional angles (S3-4), weighted
least-squares planes (S3-5), atomic coordinates and equivalent
isotropic displacement parameters (S3-6), anisotropic displace-
ment parameters (S3-7), and derived atomic coordinates and
displacement parameters for hydrogen atoms (S3-8) (49 pages).
Ordering information is given on any current masthead page.
OM950767D