Synthesis, single crystal X-ray structure determination and NMR studies of Cp2Fe(PPh2)2PtPh2 and Cp2Fe(PPh2)2PtI2

Article abstract of DOI:10.1016/S0022-328X(97)00691-8

Diphenyl[1,1′-bis(diphenylphosphino)ferrocene]platinum(II), Cp₂Fe(PPh₂)₂PtPh₂ (1) and diiodo[1,1′-bis(diphenylphosphino)ferrocene]platinum(II), Cp₂Fe(PPh₂)₂PtI₂ (2) were synthesized in nearly quantitative yield, with excellent purity by allowing Cp₂Fe(PPh₂)₂ to react with (COD)PtPh₂ and (COD)PtI₂ (COD=1,5-cyclooctadiene), respectively. Compounds 1 and 2 have been well characterized by various analytical and spectroscopic techniques and also by single crystal X-ray diffraction. Platinum in both the complexes seemed to have a distorted square planar geometry. Interestingly, the respective bite angles (P-Pt-P bond angle) in 1 (101.2(1) A) and 2 (100.6(1) A) deviate from the ideal 90° situation and are larger than in the reported structure, dppfPtCl₂ [dppf=1,1′-bis(diphenylphosphino)ferrocene]. A detailed NMR study, including 2D and simulation experiments has been performed on these compounds for complete structural assignment. The compounds 1 and 2 crystallized in triclinic space groups P1 and P1 with a=12.268(2) A, 10.089 (1); b=13.043(2) A, 10.856 (1); c=13.649(1), 17.787(1) A; α=100.49(1), 86.75(1)°; β=93.12(1), 77.52(1)°; γ=103.44(1), 64.91(1)°; V=2078.0(5), 1721.3(3) A³ and Z=2 and 2, respectively. The final refinements of 1 and 2 converged at R=0.0388 and 0.0580, respectively.

Full text of DOI:10.1016/S0022-328X(97)00691-8

Journal of Organometallic Chemistry 557 (1998) 169–179
Synthesis, single crystal X-ray structure determination and NMR
studies of Cp2Fe(PPh2)2PtPh2 and Cp2Fe(PPh2)2PtI2
Thomas J. Colacot a,*, Richard A. Teichman a, Raymundo Cea-Olivares b,
J-Guadalupe Alvarado-Rodr´ıguez b, Rube´n A. Toscano b, Walter J. Boyko c
a Organometallic Chemicals & Catalysts De6elopment, Precious Metals Di6ision, Johnson Matthey, 2001 Nolte Dri6e, West Deptford,
NJ 08066, USA
b Instituto de Qu´ımica, Uni6ersidad Nacional Auto´noma Me´xico Circuito Exterior, Ciudad Uni6ersitaria, Me´xico, 04510 D.F, Mexico
c Department of Chemistry, Villano6a Uni6ersity, Villano6a, PA 19085, USA
Received 24 June 1997
Abstract
Diphenyl[1,1%-bis(diphenylphosphino)ferrocene]platinum(II), Cp2Fe(PPh2)2PtPh2 (1) and diiodo[1,1%-bis(diphenylphos-
phino)ferrocene]platinum(II), Cp2Fe(PPh2)2PtI2 (2) were synthesized in nearly quantitative yield, with excellent purity by allowing
Cp2Fe(PPh2)2 to react with (COD)PtPh2 and (COD)PtI2 (COD=1,5-cyclooctadiene), respectively. Compounds 1 and 2 have been
well characterized by various analytical and spectroscopic techniques and also by single crystal X-ray diffraction. Platinum in both
the complexes seemed to have a distorted square planar geometry. Interestingly, the respective bite angles (P–Pt–P bond angle)
˚
˚
in 1 (101.2(1) A) and 2 (100.6(1) A) deviate from the ideal 90° situation and are larger than in the reported structure, dppfPtCl2
[dppf=1,1%-bis(diphenylphosphino)ferrocene]. A detailed NMR study, including 2D and simulation experiments has been
performed on these compounds for complete structural assignment. The compounds 1 and 2 crystallized in triclinic space groups
˚
˚
˚
P1 and P1 with a=12.268(2) A, 10.089 (1); b=13.043(2) A, 10.856 (1); c=13.649(1), 17.787(1) A; h=100.49(1), 86.75(1)°;
3
˚
i=93.12(1), 77.52(1)°; k=103.44(1), 64.91(1)°; V=2078.0(5), 1721.3(3) A and Z=2 and 2, respectively. The final refinements
of 1 and 2 converged at R=0.0388 and 0.0580, respectively. © 1998 Elsevier Science S.A. All rights reserved.
Keywords: Platinum diphosphine complexes; Homogeneous catalysts; NMR; X-ray diffraction; Triclinic
1. Introduction
tional monodentate or bidentate phosphines [1]. Among
the large variety of metal-dppf complexes, dppfPdCl2 is
one of the most widely studied systems. The synthesis
and X-ray structure of dppfPdCl2 was reported thrice in
the literature by three independent groups of workers
([2]a[3]b[10]) during the period 1984–1995, showing its
structural and theoretical importance. However, the
synthesis and the crystal structure of the analogous Pt
compound, dppfPtCl2 was reported [10] only in 1995 by
Filgueiras et. al. A variable temperature NMR report is
also available [11] on the fluxional behavior of the
Cp-protons in dppfPt(CH2SiMe2CHꢀCH2)2. Apart
from their applications in homogeneous catalysis, re-
cently Stang et.al, has explored the geometry of
dppfMCl2 (M=Pt and Pd) in supramolecular chem-
Because of their large bite angles, longer metal-phos-
phorus bonds, and cis phosphine configuration, 1,1%-
bis(diphenylphosphino)ferrocene (dppf) complexes of
precious metal groups act as far superior catalysts [1] in
homogenous catalysis, especially in Grignard cross cou-
pling reactions [2], hydrogenation reactions [3], regiose-
lective synthesis [4], olefin reduction [5], olefin
hydroformylation [6], sterospecific nucleophilic substi-
tution [7], carbonylation and carbonylative coupling [8],
and also in polymerization and poly condensation reac-
tions [9], in comparison to the complexes of conven-
* Corresponding author. e-mail: colactj@matthey.com
0022-328X/98/$19.00 © 1998 Elsevier Science S.A. All rights reserved.
PII S0022-328X(97)00691-8

170
T.J. Colacot et al. / Journal of Organometallic Chemistry 557 (1998) 169–179
istry, to prepare reactive Pt(II) and Pd(II) complexes,
suitable for the self-assembly of macromolecular
squares [12].
To our knowledge, so far no other similar examples
of dppf complexes of Pt and Pd compounds are re-
ported in the literature. Since the catalytic efficacy of a
complex is greatly influenced by the steric and elec-
tronic environment around the metal ion, M–X bond
lability (X is a group other than dppf) and the overall
geometry of the complex, we decided to focus our
attention on the synthesis of novel derivatives of these
types of compounds with a long term objective to study
their applications in homogeneous catalysis for organic
transformations. These types of complexes and their
study may serve as a prelude to our recent projects on
precious metal catalysts containing chiral biphosphines.
We are also exploring the synthesis and potential appli-
cations of Pt, Pd and Ni based dppf complexes for
Ziegler–Natta catalysis in analogy with Brookhart’s Pd
and Ni complexes of macrocyclic amines [13], and the
Table 1
Crystallographic dataa for 1b and 2b
1
2
Molecular formula C47H40Cl2FeP2Pt
C34,35H28.7Cl0.7FeI2P2Pt
recently
reported
cationic
Pt(II)
system,
Fw
988.6
Triclinic
P1
1033.0
Triclinic
P1
(Bu2bpy)MePt+ by Puddephatt [14]. Herein, we report
our preliminary results in this area on the synthesis,
X-ray structures and NMR studies of two novel Pt
compounds, one where there is a labile substituent,
iodo- on the Platinum, Cp2Fe(PPh2)2PtI2 (Fig. 2) and
the latter where the Pt is bonded to an aryl group,
Cp2Fe(PPh2)2PtPh2 (Fig. 1).
Crystal system
Space group
Unit cell dimen-
sion
a (A)
b (A)
c (A)
h (°)
i (°)
k (°)
V (A )
˚
˚
˚
12.268 (2)
130.43 (2)
13.648 (1)
100.49 (1)
93.12 (1)
103.44 (1)
2078.0 (5)
2
10.089 (1)
10.856 (1)
17.787 (1)
86.75 (1)
77.52 (1)
64.91 (1)
1721.3 (3)
2
3
˚
2. Experimental
Z
Dcalc
F(000)
1.580
980.00
1.993
973.40
2.1. General procedures
Absorption coeffi- 3.949
6.444
cient (mm−1
)
All the reactions and subsequent manipulations were
performed under a N2 atmosphere using standard
Schlenk line techniques in conjunction with a glove box
(Vacuum Atmospheres Model HE-493/MO-5). The
starting materials, Cp2Fe(PPh2)2, (COD)PtI2 and
(COD)PtPh2 were either prepared in the development
laboratory or obtained as samples from the production
facility. These materials were freshly recrystallized and
Crystal dimension 0.76×0.60×0.56
(mm)
0.44×0.28×0.14
Scan type
ꢀ
ꢀ
Scan speed in ꢀ
Deg min−1, min,
max} 2q range,
deg
4.0, 60.0
3.0, 60.0
4.0, 60.0
3.0, 60.0
Temperature (K)
Index ranges
293
05h517, −175
05h514, −135k5
1
their purities were checked by H-, 13C- and 31P-NMR
k517, −195l519 15, −245l525
spectroscopy prior to the reactions. All the solvents
were either purchased from Johnson Matthey catalog
company, Alfa–Aesar or Aldrich Chemicals and
purified using standard procedures [15].
Data collected
No. of obsd rfln,
} F\4.0|(F)
No. of params
refined
12574
9593
10569
5026
497
398
Proton, 13C- and 31P-NMR spectral data were col-
lected on a Varian XL-300 FT NMR spectrometer
operating at 300.1, 75.5 and 121.1 MHz, respectively, as
GOF
1.03
0.0388
0.0413
1.24
0.0584
0.0697
0.290, 0.010
Rc
Rw
1
CDCl3 or CD2Cl2 solution. The H and 13C shifts were
Largest and mean 0.004, 0.001
D/|
referenced to TMS in the solvent, while the 31P chemi-
cal shifts were referenced to an external standard, 85%
H3PO4. Two-dimensional carbon–hydrogen correlation
NMR (HETCOR 2D) were recorded with a standard
Varian pulse sequence. Spin simulation of the spectra
were performed on a MS-DOS PC using NUTS, a
NMR data processing from Acorn NMR. All the plat-
inum coupling constants are reported as absolute val-
ues. FT-IR spectra were obtained on a Nicolet 750
spectrophotometer using KBr pellets. Elemental analy-
sis were done at E+R Microanalytical laboratory,
Corona, NY. Melting points were determined on a
−3
−3
˚
˚
2.80 eA
Largest difference 1.42 eA
peak
−3
−3
˚
˚
−2.49 eA
Largest difference −1.29 eA
hole
Weig sch. (w−1
)
|2(Fo)+0.0004F2o
|2(Fo)+0.0008F2o
0.1335/0.9352
Min/max transmis- 0.2350/0.5300
sion
a Graphite-monochromatized Mo-Kh radiation, 1=0.71073 A.
b Both compounds 1 and 2 contain 1 and 1/3 of CH2Cl2 molecule
respectively in the crystal lattices.
˚
c R=SꢀFoꢁ−ꢁFcꢀ/SꢁFoꢁ;
Rw=[S[w(F2o−Fc2)2]/S[w(Fo2)2]]1/2
;
S=
2
[S(wꢁFo−Fcꢁ /(no. relns−no. params)]1/2
.

T.J. Colacot et al. / Journal of Organometallic Chemistry 557 (1998) 169–179
171
Table 2
3
˚
Atomic coordinates and anisotropic displacement coefficients (A×10 ) for dppfPtPh2
Atom
x
y
z
Ueq
Pt
Fe
P(1)
P(2)
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
2108(1)
4498 (1)
4048(1)
1790(1)
395(4)
2345(1)
5310(1)
2702(1)
3994(1)
1792(3)
1310(4)
944(4)
1044(5)
1488(5)
1853(5)
823(4)
7411(1)
7169(1)
7416(1)
7277(1)
7351(4)
6445(5)
6393(6)
7240(7)
8151(6)
8211(5)
76145)
27(1)
34(1)
29(1)
29(1)
35(1)
48(2)
59(2)
66(3)
62(2)
47(2)
42(2)
57(2)
86(4)
107(6)
99(5)
62(3)
34(1)
46(2)
60(3)
65(3)
60(2)
45(2)
37(2)
64(3)
91(4)
82(4)
67(3)
52(2)
67(3)
56(2)
80(3)
84(4)
88(4)
62(3)
38(2)
52(2)
67(3)
75(3)
67(3)
46(2)
32(1)
40(2)
53(2)
51(2)
41(2)
33(1)
43(2)
56(2)
55(2)
42(2)
124(7)
167(3)
310(29)
212(7)
232(10)
−253(5)
−1422(5)
−1979(5)
−1355(5)
−187(5)
2093(4)
2074(5)
2068(7)
2073(8)
2055(8)
2060(6)
4446(4)
5523(5)
5777(6)
4991(7)
3938(7)
3659(5)
4780(4)
5333(6)
5839(8)
5821(6)
5281(6)
4757(5)
509(4)
596(5)
8579(6)
8734(8)
7943(11)
6985(10)
6830(6)
6203(4)
6094(5)
5172(5)
4366(5)
4451(5)
5371(4)
8272(4)
9172(5)
9816(7)
9573(7)
8662(7)
8024(5)
6482(4)
5466(5)
4840(7)
5241(8)
6245(9)
6891(6)
8492(4)
8597(5)
9538(6)
10385(6)
10292(5)
9350(4)
6799(4)
5922(4)
5835(5)
6628(5)
7222(4)
7678(4)
7127(5)
7593(6)
8437(5)
8498(4)
2247(11)
3313(4)
2042(43)
1512(8)
1150(8)
C(9)
−442(4)
−1245(7)
−1065(6)
−28(4)
2138(4)
1977(4)
1509(5)
1206(5)
1375(4)
1833(4)
2093(4)
2681(5)
2169(8)
1113(8)
525(6)
1015(5)
3915(4)
3753(5)
3619(6)
3671(6)
3834(7)
3952(5)
4746(4)
5664(4)
6251(5)
5918(6)
5026(6)
4426(4)
4970(3)
4757(4)
5738(5)
6542(4)
6086(4)
4065(4)
4539(4)
5649(5)
5855(4)
4899(4)
1218(8)
2150(4)
2510(17)
1363(7)
1654(14)
C(10)
C(11)
C(12)
C(13)
C(14)
C(15)
C(16)
C(17)
C(18)
C(19)
C(20)
C(21)
C(22)
C(23)
C(24)
C(25)
C(26)
C(27)
C(28)
C(29)
C(30)
C(31)
C(32)
C(33)
C(34)
C(35)
C(36)
C(37)
C(38)
C(39)
C(40)
C(41)
C(42)
C(43)
C(44)
C(45)
C(46)
C(47)
C1(1A)
C1(1B)
C1(2A)
C1(2B)
527(5)
−456(7)
−1433(6)
−1469(5)
−499(5)
1623(4)
1201(5)
1144(6)
1495(7)
1897(7)
1958(5)
2817(4)
3390(4)
4156(5)
4050(5)
3237(4)
4902(4)
5772(4)
6190(4)
5617(5)
4807(5)
921(10)
1368(5)
863(14)
2125(12)
1067(10)
sof=0.80
sof=0.20
sof=0.50
sof=0.50
* Equivalent isotropic U defined as one third of the trace of the orthogonalized Uij tensor.

172
T.J. Colacot et al. / Journal of Organometallic Chemistry 557 (1998) 169–179
Table 4
Thomas–Hoover melting point apparatus using sealed
capillaries and are uncorrected.
Selected bond distances and angles of complex 1 and 2
˚
Bond distances (A)
Bond angles (°)
2.2. Synthesis of Cp2Fe(PPh2)2PtPh2
Complex 1
Pt–P(1)
Pt–P(2)
Pt–C(1)
Pt–C(7)
P(1)–C(13)
P(1)–C(19)
P(1)–C(13)
P(2)–C(25)
P(2)–C(31)
P(2)–C(37)
Fe–C(37–41) av.
Fe–C(41–46) av.
2.316(1)
2.310(1)
2.049(4)
2.050(6)
1.825(5)
1.833(6)
1.802(4)
1.831(5)
1.815(5)
1.811(5)
2.037
P(1)–Pt–P(2)
P(1)–Pt–C(7)
P(2)–Pt–C(1)
C(1)–Pt–C(7)
101.2(1)
89.1(1)
87.0(2)
To a 250 ml side arm Schlenk flask containing a
stirred
solution
of
1,1%-bis(diphenylphos-
phino)ferrocene, dppf (5.60 g, 10.1 mmol) in methylene
chloride (100 ml), (COD)PtPh2 (4.57 g, 10.0 mmol) was
82.9(2)
Pt–P(1)–C(13)
Pt–P(1)–C(19)
Pt–P(1)–C(42)
Pt–P(2)–C(25)
Pt–P(2)–C(31)
Pt–P(2)–C(37)
C(13)–P(1)–C(42)
C(13)–P(1)–C(19)
C(25)–P(2)–C(37)
C(25)–P(2)–C(31)
111.0(2)
116.1(2)
121.0(2)
114.4(2)
110.9(2)
120.9(2)
103.1(2)
102.1(2)
102.4(2)
105.2(2)
Table 3
˚
Atomic coordinates and anisotropic displacement coefficients (A×
103) for dppfPtI2
2.039
Atom
x
y
z
U(eq)
Pt
I(1)
I(2)
Fe
P(1)
P(2)
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
C(9)
C(10)
C(11)
C(12)
C(13)
C(14)
C(15)
C(16)
C(17)
C(18)
C(19)
C(20)
C(21)
C(22)
C(23)
C(24)
C(25)
C(26)
C(27)
C(28)
C(29)
C(30)
C(31)
C(32)
C(33)
C(34)
C1(1)
C1(2a)
C1(2b)
C(35)
3406(1)
1430(2)
2626(2)
7147(3)
4793(5)
3984(5)
4267(1)
6014(1)
6341(1)
380(2)
3009(3)
2624(3)
2278(1)
1527(1)
3255(1)
1871(1)
3134(2)
1361(2)
4035(9)
4188(9)
4868(11)
5412(12)
5284(11)
4583(10)
3360(10)
4098(12)
4241(14)
3633(15)
2862(14)
2755(12)
1651(9)
2335(11)
2592(16)
2119(20)
1404(18)
1156(13)
415(8)
211(12)
−527(13)
−1048(14)
−889(12)
−159(11)
2927(7)
2879(8)
2723(9)
2637(8)
2793(9)
1109(7)
1100(9)
902(9)
27(1)
77(1)
55(1)
32(1)
30(1)
29(1)
41(6)
46(7)
Complex 2
Pt–P(1)
Pt–P(2)
Pt–I(1)
Pt–I(2)
P(1)–C(1)
P(1)–C(7)
P(1)–C(25)
P(1)–C(13)
P(2)–C(19)
P(2)–C(30)
Fe–C(25–29) av.
Fe–C(25–29) av.
2.281(4)
2.285(4)
2.648(2)
2.657(1)
1.816(17)
1.831(13)
1.820(12)
1.799(19)
1.811(15)
1.820(14)
2.047
P(1)–Pt–P(2)
P(1)–Pt–I(2)
P(2)–Pt–I(1)
I(1)–Pt–C(1)
100.6(1)
84.4(1)
89.0(1)
86.1(1)
Pt–P(1)–C(1)
Pt–P(1)–C(7)
Pt–P(1)–C(25)
Pt–P(2)–C(13)
Pt–P(2)–C(19)
Pt–P(2)–C(30)
C(1)–P(1)–C(7)
C(7)–P(1)–C(25)
C(13)–P(2)–C(19)
C(19)–P(2)–C(30)
113.0(6)
112.8(5)
121.4(5)
112.2(5)
118.2(5)
114.6(6)
108.1(9)
101.7(7)
103.9(9)
100.6(6)
3653(20)
2098(22)
1262(25)
1942(29)
3453(29)
4322(23)
6031(20)
6162(29)
7108(30)
8028(26)
8005(28)
6985(29)
2996(17)
2035(25)
1317(35)
1585(31)
2441(28)
3134(22)
3621(20)
2292(26)
2048(30)
3067(41)
4438(34)
4677(25)
6066(16)
7650(19)
8171(20)
7027(21)
5638(19)
5960(17)
7135(19)
8525(22)
8235(20)
6651(20)
2492(34)
−802(47)
−708(62)
738(64)
2819(16)
3463(17)
3241(19)
2429(22)
1807(23)
1954(19)
3707(15)
3921(29)
4412(30)
4671(25)
4394(24)
3936(22)
1574(14)
1769(23)
960(30)
58(8)
66(11)
78(11)
58(8)
42(6)
2.044
82(14)
91(15)
76(11)
70(12)
66(12)
33(5)
60(10)
93(17)
95(17)
79(13)
57(8)
added all at once and stirred for another 30 min. No
noticeable color change was observed during this pe-
riod. The mixture was then refluxed overnight to obtain
a yellow solution with some precipitate. The reaction
mixture was then allowed to cool to RT, concentrated
to 10–20 ml under vacuum, followed by the addition of
Et2O (100 ml) to precipitate out the compound. The
yellow solid was then filtered using a Schlenk glass frit,
the solid was washed twice with 20 ml of Et2O, and
dried under vacuum to obtain a pale yellow crystalline
compound, 1 (9.6 g, 9.7 mmol, 97% yield). This was
further recrystallized using CH2Cl2/toluene mixture at
−15°C to obtain transparent pale yellow crystals (M.p.
192°C dec.) of dppfPtPh2.CH2Cl2. Anal. Calcd for
C47H42FeP2PtCl2: C, 56.98; H, 4.27; Fe, 5.64; Pt, 19.69.
Found: C, 56.99; H, 4.45; Fe, 5.35; Pt, 19.96. IR(cm−
1): 3140 (vw) 3109 (vw), 3082 (vw), 3048 (s), 2996 (m),
2969 (w), 1568 (s), 1478 (s), 1433 (s), 1385 (w), 1308
(m), 1264 (w), 1196 (m), 1165 (s), 1096 (s), 1064 (m),
1029 (s), 996 (m), 967 (w), 886 (w), 842 (w), 818 (m),
731 (vs), 697 (vs), 640 (m), 591 (vw), 546 (s), 519 (s),
494(vs), 465 (s), 435 (s)
−102(30)
−348(22)
535(16)
3158(14)
3322(19)
3691(18)
3903(27)
3724(24)
3405(21)
1222(13)
650(15)
−788(16)
−1073(15)
152(15)
1460(14)
1862(18)
681(22)
37(6)
57(10)
72(11)
101(19)
76(13)
63(10)
29(5)
37(6)
43(6)
39(6)
38(6)
29(5)
41(6)
58(8)
50(7)
−460(18)
24(14)
−457(23)
1152(46)
249(60)
760(9)
892(8)
4232(16)
4578(20)
4379(16)
4870(53)
39(6)
123(15)
92(23)
93(32)
73(34)
−488(46)
* Equivalent isotropic U defined as one third of the trace of the
orthogonalized Uij tensor.

T.J. Colacot et al. / Journal of Organometallic Chemistry 557 (1998) 169–179
173
Scheme 1. Synthesis of dppf PtPh2, dppf PtI2 from ferrocene.
2.3. Synthesis of Cp2Fe(PPh2)2PtI2
accurately centered reflections in the ranges, 9°52q5
25° and the intensity data were collected at 293 K in the
ranges 3°52q560°, using ꢀ scan technique. Three
standard reflections measured after every 97 reflections
did not show any significant change in intensity during
data collection for 1. A linear decay (10.5%) correction
was applied for 2 based on standards, and there was no
significant variation in the intensities of these stan-
dards. Both sets of data were corrected for Lp and
absorption effects (C-scans). The structures were solved
by direct methods [16] and refined by full matrix least
squares using anisotropic thermal parameters for all
non-hydrogen atoms. All the hydrogen atoms were
included as fixed contributions and are not refined.
Their idealized positions were generated from the ge-
ometries about the attached carbon atoms, and forced
Pt(COD)I2 (5.57 g, 10.0 mmol) was added to a stirred
solution of dppf (5.54 g, 10.0 mmol) in CH2Cl2 (100 ml)
as described above. A clear solution resulted within
minutes, which on further stirring for an hour started
to give a yellow precipitate. The stirring was continued
overnight at room temperature. The solution was then
concentrated to 1/5 th of its original volume, and mixed
with Et2O (100 ml). The resulted yellow solid was
filtered, washed with Et2O (20 ml×2) and then dried
under vacuum to obtain an analytically pure sample of
dppfPtI2 ·1/3CH2Cl2 (9.9 g, 9.6 mmol, 96% yield, M.p.
320°C dec.). Anal. Calcd for C34.33H30.66FeP2PtI2Cl0.66
:
C, 39.90; H, 2.99; Cl, 2.27; I, 24.56. Found: C, 39.89;
H, 2.94; Cl, 2.55; I, 25.27. IR(cm−1): 3081 (w), 3056
(w), 1660 (vw), 1596 (vw),1592 (vw), 1588 (vw), 1529
(vvw), 1481 (w), 1436 (s), 1387 (vw), 1308 (w), 1263
(vw), 1191 (w, sh), 1169 (w), 1096 (s), 1034 (w), 1002
(vw), 846 (vw), 824 (vw), 745 (m), 694 (vs), 639 (w), 658
(s), 495 (vs), 469 (s), 442 (w).
to ride on it with a fixed isotropic temperature factor,
2
˚
˚
U=0.08 A and C–H distances of 0.96 A. The struc-
tures were refined by using SHELXTL-PLUS PC ver-
sion [17]. The quantity minimized during the least
squares analysis was S=wꢁFo−Fcꢁ)2 where w−1
=
|(ꢁFoꢁ)+0.0008(ꢁFoꢁ)2. The final cycles of refinement of
the structures including disordered solvent molecules
are listed in Table 1, while the anisotropic temperature
factors are listed in Tables 2 and 3. The selected bond
lengths and bond angles of 1 and 2 are listed in Table
4.
2.4. X-Ray structural analysis
Pale yellow crystals of 1 were grown by diffusing
toluene into a concentrated solution of dppfPtPh2 in
dry CH2Cl2 at low temperature (−15°C), while single
crystals of 2 were obtained by slow evaporation of a
solution of CH2Cl2/hexane in an NMR tube. The crys-
tals were coated with an epoxy resin and mounted on a
Siemens P4/PC diffractometer using highly oriented
graphite-monochromated Mo-Kh (u=71073 A) radia-
tion. The final unit cell parameters summarized in
Table 1, were obtained by a least squares fit of 39
3. Results and discussion
˚
As given in Scheme 1, both Cp2Fe(PPh2)2PtPh2 and
Cp2Fe(PPh2)2PtI2 have been synthesized in high yield
with excellent purity by allowing Pt(COD)Ph2 and Pt-

174
T.J. Colacot et al. / Journal of Organometallic Chemistry 557 (1998) 169–179
Fig. 1. ORTEP diagram of Cp2Fe(PPh2)2PtPPh2, showing 30% probability ellipsoids.
Fig. 2. ORTEP diagram of Cp2Fe(PPh2)2PtI2, showing 30% probability ellipsoids.

T.J. Colacot et al. / Journal of Organometallic Chemistry 557 (1998) 169–179
175
Table 5
1H-NMR spectral data of dppf, dppfPtI2 and dppfPtPh2 inCDCl3
Atom numbering
dppf l (ppm)
dppfPtI2 l (ppm)
dppfPtPh2 l (ppm)
H2
H3
H5
H6
H7
H9
H10
H11
3.99, q (1.88 Hz)a
4.24, t
b
b
4.16, q (1.9 Hz)a
4.31, cm
7.90, cm
7.38, cm
7.45, cm
—
4.30, q (1.8 Hz)a
4.21, t
7.49, cm
7.25, cm
7.34, cm
b
—
—
—
6.87, cm (3JPt–H9=57.9 Hz)
6.43, cm
—
—
6.35, cm
Shifts in ppm relative to TMS.
q, quintet; t, triplet; cm, complex multiplet.
a Separation between major lines in multiplet.
b These shifts form a tight complex multiplet covering 7.26–7.36 ppm.
(COD)I2
to
react
with
1,1%-bis(diphenylphos-
precisely came up with the proposed structure. These
compounds on grinding followed by drying, or on long
standing for a few days at room temperature gave
analyses correspond to 1 and 2 having no solvent of
crystallization.
As expected, in both 1 and 2 the Fe atom is sand-
wiched between two staggered Cp rings. The two dis-
torted tetrahedral phosphine moieties are bonded to a
Pt atom, which is in a distorted square planar geome-
try. The most interesting aspect of the structures is that
in both compounds the bite angle (P–Pt–P) is larger
than that in the reported structure of dppfPtCl2 and is
in the order, dppfPtCl2 (99.0°) [10]Bdppf-
PtI2(100.6°)BdppfPtPh2(101.2°). The average Pt–P
bond lengths of these compounds (dppfPtCl2=2.260
phino)ferrocene, dppf in CH2Cl2 solvent. Unlike the
sythesis ([18,3]b) of the orange red colored
Cp2Fe(PPh2)2PdCl2, it has been fairly difficult to moni-
tor the reaction involving the formation of 1 visually, as
the reactants do not seem to go in to solution com-
pletely with the concomitant formation of the yellow
product. However, in the case of 2, a clear solution
resulted, upon mixing the reactants, followed by the
formation of a yellow precipitate formation.
Both compounds are soluble in chlorinated solvents
such as CH2Cl2 and CHCl3 and insoluble or sparingly
soluble in hydrocarbon solvents and ether as in the case
of Cp2Fe(PPh2)2MCl2 (M=Pt or Pd) ([2]a[3]b[10]). The
melting point of 2 is very high (320°C dec.) in compari-
son to that of 1 (192°C). This could be due the ionic
nature of the Pt–I bond. Both compounds 1 and 2 are
reasonably stable to air and moisture. However samples
kept in a vial at room temperature changed to yellowish
brown within weeks unlike the samples stored in cold
under N2.
˚
˚
˚
A, dppfPtI2=2.283 A, dppfPtPh2=2.313 A) also show
similar trends. The relatively higher bite angle and
bond distance of 1 and 2 could be due to the steric
bulkiness of the phenyl and iodo substituents on the
metal. The P· · ·P distances in dppfPtI2 and dppfPtPh2,
˚
3.510 and 3.574 A, respectively, show the same trend,
Complex 1 crystallizes very readily in a mixture of
hydrocarbon and CH2Cl2 solvent to give shining trans-
parent crystals, which become opaque and powdery on
drying due to the loss of solvent from the lattice.
Although 2 can be recrystallized in a similar way, it was
very difficult to obtain single crystals by this method.
X-ray quality crystals have been obtained only by a
careful slow evaporation of the solvent in a narrow
tube (eg. NMR tube). The crystals, especially of 2,
when not in contact with the solvent become flaky and
non diffracting. This posed further problem in solving
the structure and we had to make a dozen attempts to
get publishable quality structure.
Elemental analyses of 1 and 2 have indicated that
these compounds contain 1 and 1/3 molecules of the
solvent, CH2Cl2, respectively, in the lattice. While we
were puzzled by the elemental analysis data of 2, as it is
not very common to have a molecule with 1/3 molecule
of solvent in the lattice, an independent X-ray analysis
which is consistent with the above findings, although no
data from the literature is available for comparison.
Interestingly, the X–Pt–X (X=Cl [10], I) bond angles
of dppfPtCl2 and dppfPtI2 are very close to each other,
and are 85.8(2)° and 86.1(1)°, respectively. However,
the analogous bond angle for C–Pt–C angle in dppf-
PtPh2 is much smaller, 82.9(2)°.
In Pd chemistry, Hayashi et al. ([2]a), has made a
comparative study on the catalytic activity of dppf-
PdCl2 with that of the other bidentate phosphine com-
plexes. The study correlated that compounds with
larger P–Pd–P bond angles (bite angles) and smaller
Cl–P–Cl bond angles have superior activity and selec-
tivity in Grignard cross coupling reactions, as they can
accelerate reductive elimination due to the presence of
serious strain in the chelating system, which would be
released by the dissociation of the phosphino group.
For example, the reaction of n-butylmagnesium chlo-
ride with a series of bromobenzene derivatives, in pres-

176
T.J. Colacot et al. / Journal of Organometallic Chemistry 557 (1998) 169–179
Table 6
31P and 13C-NMR spectral data of dppf, dppfPtI2 and dppfPtPh2 inCDCl3
Atom numbering
P
dppf l (ppm)
−16.6
dppfPtI2 l (ppm)
dppfPtPh2 l (ppm)
10.1
15.7
(1JPt–P=3551.8)
(2JP–P’=7.0)
74.4
(1JPt–P=1782.9)
(2JP–P’=15.8)
[76.3]
C1
C2
76.7
(1JP–C1=7.1)
(1JP–C1=62.2)
(3JP’–C1=3.4)
2JPt–C1=34.6
75.6
[(1JP–C1=46.4)]
[(3JP’–C1=2.4)]
(2JPt–C1=25.7)
74.5
73.7
(2JP–C2=14.8)
(2JP–C2+4JP’–C2=17.1)
(3JPt–C2=a)
73.5
(2JP–C2+4JP’–C2=10.1)
(3JPt–C2=a)
C3
C4
72.4
72.5[73.0]
(NJP–C3=3.3, 1.3)
138.9
(2JP–C3+5JP’–C3=6.4)
133.1
(3JP–C3+5JP’–C3=5.8)
133.8[134.0]
(1JP–C4=9.6)
(1JP–C4=64.8)
(3JP’–C4=1.0)
(2JPt–C4=34.6)
135.2
(1JP–C4=48.4)
(3JP’–C4=1.6)
(2JPt–C4=24.4)
134.5 [134.8]
C5
C6
133.4
(2JP–C5=19.6)
(2JP–C5+4JP’–C5=10.7)
(3JPt–C5=a)
127.7
(2JP–C5+4JP’–C5=11.2)
(3iJPt–C5=16.7)
127.5 [127.9]
128.1
(3JP–C6=6.4)
(3JP–C6+5JP’–C6=11.7)
(4JPt–C6= :0)
130.1
(3JP–C6+5JP’–C6=9.8)
(4JPt–C6= :0)
129.1 [129.9]
C7
C8
128.4
(4JP–C7= :0)
(4JP–C7= :0)
—
(4JP–C7= :0)
160.7 [161.7]
—
(2JP–C8=11.5, cis; 110.8, trans)
(1JPt–C8=848.2)
136.2 [136.6]
C9
—
—
—
—
—
—
(3JP–C9 cis+trans=b)
(1JPt–C9=29.4)
126.9 [127.2]
C10
C11
(4JP–C1 0 cis+trans=5.8)
(3JPt–C10=66.6)
120.3 [120.7]
(5JP–C11= :0)
(4JPt–C11=11.4)
Data in square brackets refer to the values in CD2Cl2 solvent. Coupling constants are absolute values in Hz, and are given in parenthesis.
a Cannot report JPt–C due to the overlap of 195Pt satellite lines 1 and 5 of AXX% pentuplet.
b Line broadening obscures coupling, but less than 3 Hz.
ence of dppePdCl2 and dpppPdCl2 gave 0–4% and
4–75% yields of the coupled products respectively,
while dppfPdCl2 gave above 95% yield in most of the
cases. This difference in reactivity is attributed to their
respective P–Pd–P bond angles, 85.5°, 90.6° and 99.07°
for dichloro[1,1%-bis(diphenylphosphino)ethane]palla-
dium(II) [19], dichloro[1,1%-bis(diphenylphosphino)-
propane]palladium(II) [19] and dichloro[1,1%-bis(-
diphenylphosphino)ferrocene]palladium(II). Although
we have not done any similar catalytic studies, the
above data suggest that our compounds may be equally
good or even superior, in related studies.
The phosphorus atoms in both these complexes are
distorted from the ideal tetrahedral geometry. For ex-
ample, the Pt–P–C(Cp) bond angles of 1 deviate from
the ideal tetrahedral angle, 109.45°, to an average bond
angle of 121°. In complex 2, the two Pt–P–C(Cp) bond
angles are non identical, and are 121.4(5)° and
114.6(6)°, respectively for P(1) and P(2) centers.
3.1. NMR spectral study
1H- and 13C-NMR chemical shifts with the coupling
constants are given in Tables 5 and 6, respectively, for
dppf, dppfPtI2 and dppfPtPh2 (Fig. 3). Proton and 13C
shifts for dppf are available in the literature [20] with
no listings of coupling constants.
The phenyl protons in dppf have close shift values
and are reported as a range. This is similar to the
pattern obtained for triphenylphosphine in CDCl3. Co-
ordination to Pt diverges all phenyl ring proton shift
values. The ortho proton patterns become easy to iden-
tify by appearance. This allows absolute identification

T.J. Colacot et al. / Journal of Organometallic Chemistry 557 (1998) 169–179
177
phenyl ring of dppf. The quartet is used to distinguish
H-2 from H-3 in dppfptI2 and dppfPtPh2. 195Pt satel-
lites were found for H-9 in dppfPtPh2, but no other
protons appeared to have measurable Pt satellites. A
HETCOR 2D-map shown in Fig. 4 is used to confirm
all phenyl carbon assignments for dppfPtPh2. These are
used to confirm assignments in dppfPtI2. Low resolu-
tion HETCOR is used to correlate cyclopentadienyl
carbon shifts. C-2 and C-3 keep the same relative shift
order in dppf, dppfPtI2 and dppfPtPh2, but H-2 and
H-3 change shift positions in dppfPtPh2. This may be
due to a slight shielding effect at the cyclopentadienyl
ring when phenyl rings are put on to the Pt atom. It
should be noted that, except for C-8 shift, the carbon
shifts and JPt-C couplings of the Pt-phenyls are quite
similar to trans-PhPt(AsMe2)2Cl [21].
Fig. 3. Numbering scheme used to interpret the NMR spectra of
dppf, dppfPtI2 and dppfPtPh2.
Most of the carbon resonances in dppf appear as
simple doublets due to the couplings with the phospho-
rus atom. However C-3 has two couplings, the smaller
one could be due to a long-range coupling through the
ferrocene iron to the phosphorus atom. As reported in
the literature, coordination to the Pt results in a high
order pattern [22] due to the presence of a non-zero
of all other phenyl protons. For the cyclopentadienyl
ring, the assignment of the quartet in the free ligand to
H-2 is based on the additional coupling coming from
phosphorus. In the absence of this coupling, it is ex-
pected that H-2 and H-3 would be ‘triplet like’ from a
high order AA%XX% system.
A low resolution HETCOR shows H-2 correlated
with the cyclopentadienyl carbon with the larger phos-
phorus coupling, in analogy with C-5 and C-6 in the
2
value for JP–P%. The high order patterns were simulated
to extract the correct J values. The carbon–phosphorus
couplings reported in Table 5 are as absolute values,
although certain sign relationships are required to ob-
tain the correct computer simulation for each multiplet.
Fig. 4. A section of the 2D HETCOR map of dppfPtPh2, showing the P–phenyl and Pt–phenyl region.

178
T.J. Colacot et al. / Journal of Organometallic Chemistry 557 (1998) 169–179
Fig. 5. Simulated (a) and experimental (b) spectrum of the C6 resonance of dppfPtPh2 (CD2Cl2, 75.5 MHz).
The major pattern in the carbon resonances for C-1, C-4
and C-8 in dppfPtI2 and dppfPtPh2 are a doublet of
doublets, except for C-4 of dppfPtI2, which is a doublet.
All of these resonances also show a minor 1.5–2.0 Hz
doublet in the center of the pattern. The absolute value
lated C6 resonances in the 13C spectrum of dppfPtPh2 is
given in Fig. 5.
The 31P-NMR shifts are listed in Table 6. The chem-
ical shift for dppfPtI2 (10.1 ppm) is similar to that in the
chloro analog, dppfPtCl2 (13.6 ppm) [10]. Replacement
of iodine by Ph in dppfPtPh2 shifts the value to 15.7
ppm. A previously reported value (124.14 ppm) [10] for
the ligand, dppf, seems to be an error. Our shifts for
dppf (−16.6 ppm) is same as the reported value, −16.6
ppm [20]. The Pt–P coupling constants present no
surprises. The 1JPt–P coupling in dppfPtI2 (3551.8 Hz) is
very close to that in the chloro analog [10]. A decreased
1JPt–P value (1782.9 Hz) in dppfPtPh2 reflects the well
known trans influence [24] of an aryl or alkyl group.
2
of JP–P% is required to simulate the multiplets at C-1,
C-4 and C-8 in dppfPtI2 and dppfPtPh2, although either
sign gives the correct simulation. Since the resonances
for C-2, and C-5 in the Pt complexes were obscured by
Pt satellites, and the lines in C-3 resonances were
2
masked by noise, we could not determine the JP–P%
values from these multiplets. However, accurate deter-
2
mination of JP–P% was achieved by using lines 1 and 5
1
3
in C-6 resonances. The relative sign of JP–C and JP%–C
must be of the same convention to get the correct
simulation of C-1 and C-4 resonances in both com-
plexes. The proper simulation of C-8 in dppfPtPh2
requires that 2JP–C8 cis and trans couplings should be of
opposite sign. This is similar to the case of a carbon–
3.2. Summary
Two potential Pt based homogenous catalysts were
synthesized in nearly quantitative yield with excellent
purity and were characterized unambiguously. The ac-
tivities of these complexes are being tested elsewhere.
The synthesis of Pd–alkyl based complexes are cur-
rently in progress in our laboratory, mainly to investi-
gate their potential applications in organic synthesis and
also in polymer synthesis using homogeneous catalysis.
phosphorus
coupling
through
Pt
in
cis-
N
N+2
[PtMe2(PMe2Ph)2] [23]. Values for ꢁ JP–C
+
J
ꢁ
P%–C
among the remaining carbons are derived from the
difference in lines 2 and 4 in pentuplets of C-2, C-3, C-5,
C-6, and C-10 in dppfPtI2 and dppfPtPh2. An example
of the pentuplet pattern for the experimental and simu-

T.J. Colacot et al. / Journal of Organometallic Chemistry 557 (1998) 169–179
179
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Observed and calculated structure factors, complete
list of bond angles and bond lengths, and final atomic
coordinates with anisotropic displacement coefficents
are deposited. Ordering information is given on any
current masthead page.
Acknowledgements
Acknowledgments are due to Dr William H. Tam-
blyn, Technical Director, Chemicals and Catalysts De-
velopment, Precious Metals Division, Johnson
Matthey, West Deptford, New Jersey for the encour-
agement in this work. Dr Ernest S. Gore of the same
department is also thanked for the useful discussion.
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