Cationic (tripyrrinato)palladium(II) complexes

Article abstract of DOI:10.1016/j.ica.2005.04.011

The formation of cationic palladium(II)complexes [TrpyPd^II] ⁺X^- by salt metathesis of the respective trifluoroacetates with different salts of weakly coordinating anions X^- was investigated. With non-hydrolizable counterions, cationic mono- and dinuclear complexes are observed depending on the nature of the anion X^- and the solvent. The mononuclear cations, which are only formed with X = BAr ^F, most probably carry a weakly bound molecule of dichloromethane at the fourth coordination site of Pd^II. When treated with diazoalkanes, only these are sufficiently reactive to form carbene complexes. Four- and five coordinate Lewis base adducts [TrpyPd^IIL]⁺ with L = CH₃NC, tBuNH₂, PMe₃, PEt₃ and PiPr₃ and [TrpyPd^IIL₂]⁺ with L = PMe₃ were prepared from the mononuclear cations [TrpyPd ^II]⁺BAr^F-. From structural studies it becomes apparent, that the formation of stable five coordinate Pd^II species is restricted to medium size ligands and depends on the delicate balance between the steric influence of L and the strain, which is induced on the TrpyPd ^II unit.

Full text of DOI:10.1016/j.ica.2005.04.011

Inorganica Chimica Acta 358 (2005) 3122–3134
www.elsevier.com/locate/ica
Cationic (tripyrrinato)palladium(II) complexes
*
Martin Broring , Carsten D. Brandt, Stephan Link
¨
Prof. Dr. Martin Bro¨ring, Philipps-Universita¨t Marburg, Fachbereich Chemie, Hans-Meerwein-Straße, D-35043 Marburg, Germany
Received 10 February 2005; accepted 6 April 2005
Available online 23 May 2005
Abstract
The formation of cationic palladium(II)complexes [TrpyPdII]+Xꢀ by salt metathesis of the respective trifluoroacetates with dif-
ferent salts of weakly coordinating anions Xꢀ was investigated. With non-hydrolizable counterions, cationic mono- and dinuclear
complexes are observed depending on the nature of the anion Xꢀ and the solvent. The mononuclear cations, which are only formed
with X = BArF, most probably carry a weakly bound molecule of dichloromethane at the fourth coordination site of PdII. When
treated with diazoalkanes, only these are sufficiently reactive to form carbene complexes. Four- and five coordinate Lewis base
adducts [TrpyPdIIL]+ with L = CH3NC, tBuNH2, PMe3, PEt3 and PiPr3 and [TrpyPdIIL2]+ with L = PMe3 were prepared from
the mononuclear cations [TrpyPdII]+BArFꢀ. From structural studies it becomes apparent, that the formation of stable five coordi-
nate PdII species is restricted to medium size ligands and depends on the delicate balance between the steric influence of L and the
strain, which is induced on the TrpyPdII unit.
ꢀ 2005 Elsevier B.V. All rights reserved.
Keywords: Tripyrrin; Oligopyrroles; Palladium; X-ray structure determination; Strain
1. Introduction
methyl)phenyl]borate), leading to the highly reactive
[TrpyPdII]+BArFꢀ (2). The cationic complex fragment
[TrpyPdII]+ of 2 exhibits an unprecedented reactivity
and was successfully used for the preparation of the first
stable palladium(II) complex with a non-heteroatomsta-
bilised carbene ligand 3 [4] and for the investigation of a
pentacoordinate PdII complex 4 stable in solution and in
the solid state [5]. The electronically and coordinatively
unsaturated character of 2, however, has not been pro-
ven so far neither in solution nor in the solid state,
and a ‘‘naked’’ structure of 2 as depicted in Scheme 1
is therefore still questionable. Three coordinate 14VE
d8 complexes are rare, but known and have been struc-
turally characterised in several instances [6]. On the
other hand do coordinatively unsaturated d8 species
tend to bind even the weakest Lewis bases like C–H
bonds [7–10], and kinetic investigations of ligand ex-
change processes of square-planar 16VE complexes have
resulted in the observation of associative mechanisms
throughout [11–13]. It is therefore in question, whether
2 is a 14VE cation or a 16VE solvent adduct.
Neutral palladium(II) complexes of a,x-dimethyltri-
pyrrin ligands are typically characterised by the steric
repulsion which is present between the anionic co-ligand
and the two methyl groups C-1 and C-16 situated at the
termini of the open-chain tripyrrole (methyl termini) [1].
The steric overcrowding at the open site of the linear tri-
pyrrole leads to strained, nonplanar structures, and
sometimes fluxional behaviour is observed as shown
for the trifluoroacetato derivative TrpyPdIIOAcF (1) in
Scheme 1 [2,3]. The exchange of the trifluoroacetato li-
gand of 1 against a non coordinating anion should result
in a marked decrease of intramolecular strain. Such an
exchange can easily be carried out by salt metathesis
of 1 with NaBArF (BArF = tetrakis-[3,5-bis(trifluoro-
*
Corresponding author. Tel.: +49 (0) 6421 282 5418; fax: +49 (0)
6421 282 5653.
E-mail address: martin.broering@chemie.uni-marburg.de
(M. Bro¨ring).
0020-1693/$ - see front matter ꢀ 2005 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2005.04.011

M. Bro¨ring et al. / Inorganica Chimica Acta 358 (2005) 3122–3134
3123
theses were carried out under inert conditions using
Schlenck techniques. NMR spectra were obtained on a
Bruker AMX 400 spectrometer and measured at room
temperature unless stated otherwise. Mass spectra were
recorded on a Finnigan 90 MAT instrument. m/z values
are given for the most abundant isotopes only. Melting
points were measured by DTA on a Thermoanalyzer
DuPont 9000.
2.2. X-ray structural determinations
Selected crystal data and structure refinement param-
eters for 7, 8, 13, 15 and 17 are collected in Table 1. For
each study, a single violet crystal was mounted on a
glass fibre, and data were collected at 173 K on a Bruker
Smart-Apex diffractometer with D8-goniometer using
graphite-monochromated Mo Ka radiation. A semi-
empirical absorption correction was applied. The struc-
tures were solved by Patterson (13, 15) or direct methods
(7, 8, 17) (SHELXS) [14] and refined against F2 by least-
squares (SHELXL) [15]. All non-hydrogen atoms were re-
fined anisotropically. Selected bond length, distances
and angles for 7/8 and 13/15/17 are given in Tables 2
and 3, respectively.
2.3. Syntheses of complexes
Salt metathesis of trifluoroacetato(3,4,8,9,13,14-hexa-
ethyl-2,15-dimethyltripyrrinato)-palladium(II) (1) with
sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate
NaBArF. Formation of cation 2.
A solution of
TrpyPdIIOAcF (1) (44 mg, 69 lmol) in dichloromethane
(25 ml) is treated with NaBArF (61.3 mg, 69 lmol) and
stirred at r.t. for 16 h. The green solution is then filtered
through celite and the solvent evaporated in vacuo. The
residue is washed several times with cold pentane and fi-
nally dried in vacuo to yield the title compound as a vio-
let solid.
Scheme 1. Activation of TrpyPdIIOAcF 1 to the cationic complex 2
and transformations to palladium(II) carbene 3 and the pentacoordi-
nated species 4.
As a common feature, the putative 14VE complex 2
and the fully characterised 18VE complex 4 can both
be addressed as non strained species with respect to 1,
and the release of strain can easily be regarded as the
major driving force in the formation of 2 and 4. This pa-
per presents new synthetic and structural details towards
the nature of 2 and the scope and limitations of observ-
ing 18VE species like 4.
6 was prepared from TrpyPdIIOAcF (5) using the
same protocol, but could not be analysed due to the vast
amount of by-products.
Spectroscopic data for 2. (71 mg, 74%), m.p. 87 ꢁC
(decomp.) (C60H50BF24N3PdÆCH2Cl2 requires: C,
49.80; H, 3.56; N, 2.86. Found: C, 50.02; H, 3.84;
N, 3.02%). 1H NMR (CD2Cl2, 295 K): d 1.09 (t,
3
3
6H, JHH = 7.6 Hz, 2 · CH2CH3), 1.15 (t, 6H, JHH
=
3
7.6 Hz, 2 · CH2CH3), 1.21 (t, 6H, JHH = 7.6 Hz,
2 · CH2CH3), 2.42 (q, 4H, 3JHH = 7.6 Hz, 2 ·
CH2CH3), 2.55 (s, 6H, 2 · terminal CH3), 2.58 (q,
2. Experimental
3
4H, JHH = 7.6 Hz, 4 · CH2CH3), 2.62 (q, 4H,
2.1. General remarks
3JHH = 7.6 Hz, 4 · CH2CH3), 6.94 (s, 2H, 2 · meso-
H), 7.57 (s, 4H, 4 · para-H), 7.73 (s, 8H, 8 · ortho-
H). 13C NMR (CD2Cl2, 295 K): d 14.8, 16.7, 17.1,
All reagents were either prepared from literature pro-
cedures cited in the text or purchased from commercial
sources and used as received. Solvents were dried using
standard procedures and stored under argon. All syn-
17.4, 18.0, 18.5, 18.7, 117.9 [s(br), 4 · para-C], 121.7,
1
125.0 (q, JCF
=
272.1 Hz, 8 · CF3), 129.0 (qq,
3
2JCF = 31.5 Hz, JBC = 2.9 Hz, 8 · meta-C), 135.2 (s,

3124
M. Bro¨ring et al. / Inorganica Chimica Acta 358 (2005) 3122–3134
Table 1
Crystal data and structure refinement parameters for 7, 8, 13, 15 and 17
Compound
7ÆCH2Cl2
8
13
C91H90BCl2F27N6O2Pd2 C82H72BF27N6O2Pd2 C62H53BF24N4Pd
15
C60H53BF24N4Pd
1403.27
17
C59H51BF24N3PPd
1406.21
Empirical formula
Formula weight
Crystal size (mm)
T (K)
2107.20
1910.07
1427.29
0.20 · 0.20 · 0.12
193
0.71073
0.20 · 0.16 · 0.12
173
0.71073
0.70 · 0.51 · 0.43
223
0.71073
0.20 · 0.20 · 0.10
173
0.71073
0.20 · 0.20 · 0.12
173
0.71073
˚
Wavelength (A)
Crystal system
Space group
Unit cell dimensions
triclinic
ꢀ
triclinic
ꢀ
triclinic
ꢀ
triclinic
ꢀ
triclinic
ꢀ
P1 (No. 2)
P1 (No. 2)
P1 (No. 2)
P1 (No. 2)
P1 (No. 2)
˚
a (A)
17.673(4)
17.750(4)
18.212(4)
101.89(3)
102.86(3)
115.23(3)
4736.0(16)
2
15.3063(2)
16.7944(2)
18.2460(2)
102.840(1)
106.981(1)
107.199(1)
4033.40(8)
2
13.703(9)
14.722(10)
17.487(12)
89.844(11)
72.933(10)
72.301(11)
3198(4)
13.9049(13)
14.2514(13)
15.7745(14)
95.285(1)
91.404(1)
93.979(1)
3103.6(5)
2
13.4866(11)
14.1020(12)
16.2322(14)
77.610(1)
88.728(1)
88.558(1)
3013.9(4)
2
˚
b (A)
˚
c (A)
a (ꢁ)
b (ꢁ)
c (ꢁ)
3
˚
V (A )
Z
2
1.22–26.37
Range for data
collection, h (ꢁ)
Index ranges
1.36–25.00
1.51–25.00
1.30–25.35
1.28–25.00
ꢀ21 6 h 6 21
ꢀ21 6 k 6 21
ꢀ21 6 l 6 21
0.539
ꢀ18 6 h 6 17
ꢀ19 6 k 6 19
ꢀ21 6 l 6 21
0.560
ꢀ17 6 h 6 17
ꢀ18 6 k 6 18
ꢀ21 6 l 6 21
0.402
ꢀ16 6 h 6 16
ꢀ17 6 k 6 17
ꢀ18 6 l 6 18
0.413
ꢀ16 6 h 6 16
ꢀ16 6 k 6 16
ꢀ19 6 l 6 19
0.450
l (mmꢀ1
Reflections collected,
Ncollected
)
78570
68221
50440
28982
35967
Independent reflections, 16627 (Rint = 0.0502)
Nunique
14189 (Rint = 0.0477) 13038 (Rint = 0.0195) 11207 (Rint = 0.0340) 10585 (Rint = 0.0201)
Observed reflections
(I > 2r(I)), Nobs
Goodness of fit
(I > 2r(I))
12697
12383
11904
10578
9886
1.053
1.138
1.038
1.477
1.060
Final R indices
(I > 2r(I))
R1 = 0.0485
R1 = 0.0544
R1 = 0.0386
R1 = 0.0881
R1 = 0.0353
wR2 = 0.1249
R1 = 0.0670
wR2 = 0.1332
wR2 = 0.1168
R1 = 0.0641
wR2 = 0.1031
R1 = 0.0421
wR2 = 0.1530
R1 = 0.1005
wR2 = 0.0871
R1 = 0.0379
R indices (all data)
wR2 = 0.1211
1.380 and ꢀ1.068
wR2 = 0.1065
0.927 and ꢀ0.478
wR2 = 0.1567
0.867 and ꢀ0.558
wR2 = 0.0885
0.747 and ꢀ0.386
Largest difference peak 0.785 and ꢀ0.723
ꢀ3
˚
and hole (e A
)
Table 2
Table 3
˚
˚
Selected bond lengths (A) and bond angles (ꢁ) for the cationic
complexes 7 and 8
Selected bond lengths (A) and bond angles (ꢁ) for the cationic
TrpyPdIIL complexes 13, 15 and 17
7
8
13 [D = C(29)]
15 [D = N(4)]
17 [D = P(1)]
Subunit I
Subunit II Subunit I
Subunit II
3.412
Pd–N(1)
Pd–N(2)
Pd–N(3)
Pd–D
2.034(2)
2.010(2)
2.041(2)
1.949(3)
2.039(4)
2.013(4)
2.040(4)
2.101(4)
2.0425(19)
2.0785(18)
2.0436(19)
2.3122(7)
Pd(1)ꢁ ꢁ ꢁPd(2)
Pd(1)–N(1)a
Pd(1)–N(2)
Pd(1)–N(3)
Pd(1)–O(1)
3.165
2.060(3)
1.979(3)
2.013(3)
2.061(3)
2.023(4)
1.976(3)
2.048(3)
2.069(3)
2.045(3)
1.982(3)
2.019(3)
2.083(3)
2.020(3)
1.975(3)
2.054(3)
2.054(3)
C(1)ꢁ ꢁ ꢁC(16)
C(1)ꢁ ꢁ ꢁD
4.757
3.032
2.940
4.680
3.148
3.128
4.750
3.486
3.458
C(16)ꢁ ꢁ ꢁD
C(1)ꢁ ꢁ ꢁC(16)
C(1)ꢁ ꢁ ꢁO(1)
C(16)ꢁ ꢁ ꢁO(1)
4.962
2.805
2.864
5.119
2.881
2.819
4.882
2.882
2.866
4.992
2.876
2.862
N(1)–Pd–N(2)
N(1)–Pd–N(3)
N(1)–Pd–D
89.90(9)
169.28(7)
90.87(9)
91.21(9)
159.09(9)
91.89(9)
90.73(17)
167.45(16)
91.82(19)
90.67(17)
155.96(17)
91.98(19)
90.10(7)
169.45(8)
93.01(6)
89.92(8)
143.20(6)
93.28(6)
N(1)–Pd–N(2)
92.85(12)
89.23(13)
91.95(13)
88.31(14)
N(1)–Pd–N(3) 168.22(12) 169.60(12) 168.36(13) 168.67(14)
N(2)–Pd–N(3)
N(2)–Pd–D
N(3)–Pd–D
N(1)–Pd–O(1)
N(2)–Pd–N(3)
N(2)–Pd–O(1) 167.24(11) 170.00(11) 164.93(13) 166.62(13)
93.64(11)
89.18(12)
85.56(12)
91.58(13)
95.78(12)
89.32(14)
85.36(13)
92.60(14)
N(3)–Pd–O(1)
86.71(12)
95.09(12)
85.72(13)
95.92(13)
8 · ortho-CH), 137.2, 138.6, 138.7, 141.0, 152.6, 162.2
1
(q, JBC = 49.0 Hz, 4 · ipso-C), 173.3. 19F NMR
a
The numbering scheme used for the subunits II in this table devi-
ates from the graphics, but follows the same logical order.
(CD2Cl2): d ꢀ62.7. 1H NMR (CD2Cl2, 183 K): d

M. Bro¨ring et al. / Inorganica Chimica Acta 358 (2005) 3122–3134
3125
0.90–096 (m, 18H, 6 · CH2CH3), 1.96 (s, 6H, 2 · ter-
the residue is washed several times with cold pentane
and finally dried in vacuo to yield the title compound
as a violet solid.
3
minal CH3), 2.02 (q, 4H, JHH = 7.6 Hz, 2 · CH2CH3),
2.20–2.32 (m, 8H, 4 · CH2CH3), 6.24 (s, 2H, 2 ·
meso-H), 7.54 (s, 4H, 4 · para-H), 7.73 (s, 8H,
8 · ortho-H). 13C NMR (CD2Cl2, 183 K): d 14.5
Spectroscopic data for 8. (45 mg, 74%), m.p. 145 ꢁC
(decomp.) (C82H72BF27N6O2Pd2 requires: C, 51.56; H,
1
3.80; N, 4.40. Found: C, 51.88; H, 4.04; N, 4.46%). H
1
1
[q(br), JCH = 79.2 Hz, 2 · CH2CH3], 16.0 (q, JCH
=
=
1
129.0 Hz, 2 · terminal CH3), 17.0 [q(br), JCH
NMR (CD2Cl2):
d
1.01 (t, 12H,3JHH = 7.6 Hz,
1
3
126.4 Hz, 2 · CH2CH3], 17.2 [q(br), JCH = 127.5 Hz,
4 · CH2CH3), 1.07 (t, 12H, JHH = 7.6 Hz, 4 · CH2-
2 · CH2CH3], 17.3 [t(br), 1JCH = 128.6 Hz, 2 ·
CH3), 2.16 (s, 12H, 4 · terminal CH3), 2.26 (q, 8H,
1
3
CH2CH3], 17.4 [t(br), JCH = 130.1 Hz, 2 · CH2CH3],
3JHH = 7.6 Hz, 4 · CH2CH3), 2.38 (q, 8H, JHH
=
1
17.5 [t(br), JCH = 132.5 Hz, 2 · CH2CH3], 117.1
7.6 Hz, 4 · CH2CH3), 6.45 (br s, 8H, 4 · meso-
H + 4 · Haryl), 7.52 (s, 4H, 4 · para-H), 7.72 (s, 8H,
8 · ortho-H). 13C NMR (CD2Cl2): d 14.2, 16.8, 16.9,
18.4, 22.7, 117.8 [s(br), 4 · para-C], 121.7, 125.0 (q,
1JCF = 272.2 Hz, 8 · CF3), 125.6, 129.2 [q(br),
2JCF = 31.5 Hz, 8 · meta-C], 135.2 [s(br), 8 · ortho-C],
1
[d(br), JCH = 157.0 Hz, 2 · meso-CH + 4 · para-H],
1
2
123.9 (q, JCF = 272.9 Hz, 8 · CF3), 128.0 (q, JCF
=
1
31.6 Hz, 4 · meta-C), 134.1 (d, JCH = 161.3 Hz,
8 · ortho-CH), 1 35.7, 136.9, 137.3, 137.9, 146.9,
1
161.2 (q, JBC = 49.0 Hz, 4 · ipso-C), 171.7.
Preparation of (l2-trifluoroacetato)bis[(3,4,8,9,13,
14-hexaethyl-2,15-dimethyl-tripyrrinato)palladium(II)]
tetrakis-[3,5-bis(trifluoromethyl)phenyl]borate (7). A
solution of TrpyPdIIOAcF (1) (43 mg, 67 lmol) in
dichloromethane (25 ml) is treated with NaBArF
(29.8 mg, 33.5 lmol) and stirred at r.t. for 16 h. The
green solution is then filtered through celite and the sol-
vent evaporated to 1 ml in vacuo, layered with pentane
(10 ml) and cooled to ꢀ60 ꢁC for 5 h. After filtration
the residue is washed several times with cold pentane
and finally dried in vacuo to yield the title compound
as a violet solid.
139.0, 139.4, 148.8, 162.1 (q, JBC = 49.9 Hz, 4 · ipso-
1
C). The signal at ꢂ174 ppm was not resolved unambi-
gously. 19F NMR (CD2Cl2): d ꢀ63.2 (s, 24F, 8 · CF3),
ꢀ73.1 (s, 3F, CF3CO2).
Preparation of diphenylmethylidene[3,4,8,9,13,14-
hexaethyl-2,15-dimethyltripyrrinato-palladium(II)]
tetrakis-[3,5-bis(trifluoromethyl)phenyl]borate (9).
A
solution of TrpyPdIIOAcF (1) (52.4 mg, 82.4 lmol) in
dichloromethane (25 ml) is treated with NaBArF
(73.0 mg, 82.4 lmol) and stirred at r.t. for 16 h. The
green solution is then filtered through celite, the filtrate
cooled to ꢀ100 ꢁC and treated with a solution of
diphenyldiazomethane (16.0 mg, 52.4 lmol) in dichlo-
romethane (5 ml). The mixture was warmed slowly to
r.t. and the solvent was evaporated in vacuo to leave
a dark residue. This residue was washed repeatedly
with cold pentane and dried to give a violet solid,
which was recrystallised from dichloromethane/pentane
(1/10) at ꢀ60 ꢁC.
Spectroscopic data for 7. (66 mg, 97%), m.p. 121 ꢁC
(decomp.) (C90H88BF27N6O2Pd2 ÆCH2Cl2 requires: C,
51.30; H, 4.21; N, 3.99. Found: C, 51.54; H, 4.42; N,
3.78%). 1H NMR (CD2Cl2):
d
1.02 (t, 12H,
3
3JHH = 7.6 Hz, 4 · CH2CH3), 1.05 (t, 12H, JHH
=
3
7.6 Hz, 4 · CH2CH3), 1.09 (t, 12H, JHH = 7.6 Hz,
4 · CH2CH3), 2.11 (br s, 12H, 4 · terminal CH3), 2.25
3
(q, 8H, JHH = 7.6 Hz, 4 · CH2CH3), 2.37, 2.39 (2 · q,
Spectroscopic data for 9. (118.9 mg, 93%), m.p.
100 ꢁC (decomp.) (C73H60BF24N3Pd requires: C, 56.48;
H, 3.90; N, 2.71. Found: C, 56.69; H, 4.12; N, 2.76%).
16H, 8 · CH2CH3), 6.39 (s, 4H, 4 · meso-H), 7.57 (s,
4H, 4 · para-H), 7.73 (s, 8H, 8 · ortho-H). 13C NMR
(CD2Cl2): d 14.7, 16.7, 17.0, 17.3, 18.3, 18.4 (s, 4 ·
C H2CH3), 117.8 (br s, 4 · para-C), 118.5, 125.0 (q,
3
1H NMR (CD2Cl2): d 0.54 (t, 6H, JHH = 7.6 Hz,
2 · CH2CH3), 0.89 (t, 6H, 3JHH = 7.6 Hz, 2 · CH2CH3),
1.01–1.28 (m, 14H, 2 · CH2CH3 + 4 · CH2CH3), 1.43
2
1JCF = 271.8 Hz, 8 · CF3), 129.2 (qq, JCF = 31.5 Hz,
3JBC = 2.9 Hz, 8 · meta-C), 135.2 (br s, 8 · ortho-C),
137.1, 138.4, 138.7, 139.0, 148.3, 162.1 (q,
1JBC = 49.9 Hz, 4 · ipso-C), 172.7. 19F NMR (CD2Cl2):
d ꢀ62.8 (s, 24F, 8 · CF3), ꢀ73.2 (s, 3F, CF3CO2). MS
(EI, 70 eV): m/z 635 [M ꢀ (TrpyPd) ꢀ BArF]+, 522
[M ꢀ (TrpyPd) ꢀ BArF ꢀ OAcF]+.
(s, 6H, 2 · terminal CH3), 2.57 (q, 4H, JHH = 7.6 Hz,
3
2 · CH2CH3), 6.91 (s, 2H, 2 · meso-H), 7.57 (s, 4H,
4 · para-H), 7.64 (AA0BB0C, 8H, 8 · Haryl), 7.74 (s,
8H, 8 · ortho-H). 13C NMR (CD2Cl2): d 14.2, 17.1,
17.4, 17.9, 18.5, 21.0, 22.7, 117.8 [s(br), 4 · para-C],
1
122.1, 125.0 (q, JCF = 272.1 Hz, 8 · CF3), 129.2 (qq,
Preparation of (l2-trifluoroacetato)bis[(3,4,13,14-
tetraethyl-2,15-dimethyl-tripyrrinato)-palladium(II)]
tetrakis-[3,5-bis(trifluoromethyl)phenyl]borate (8). A
solution of TrpyPdIIOAcF (5) (37.2 mg, 64 lmol) in
dichloromethane (25 ml) is treated with NaBArF
(28.4 mg, 32 lmol) and stirred at r.t. for 16 h. The green
solution is then filtered through celite and the solvent
evaporated to 1 ml in vacuo, layered with pentane
(10 ml) and cooled to ꢀ60 ꢁC for 5 h. After filtration
2JCF = 31.8 Hz, JBC = 2.6 Hz, 8 · meta-C), 135.2 (br s,
3
8 · ortho-C), 136.3, 137.1, 138.5, 139.0, 140.0, 140.4,
140.7, 148.3, 151.6, 152.0, 162.1 (q, JBC = 49.9 Hz,
1
4 · ipso-C), 174.2, 326.0 (s, Pd=C). 19F NMR (CD2Cl2):
d ꢀ62.7. MS (EI, 70 eV): m/z 688 [M ꢀ BArF]+.
Preparation of di(p-tolyl)methylidene[3,4,13,14-tetra-
ethyl-2,15-dimethyltripyrrinato-palladium(II)]tetrakis-
[3,5-bis(trifluoromethyl)phenyl]borate (10). A solution
of TrpyPdIIOAcF (5) (35 mg, 66 lmol) in dichlorometh-

3126
M. Bro¨ring et al. / Inorganica Chimica Acta 358 (2005) 3122–3134
ane (25 ml) is treated with NaBArF (59.0 mg, 66 lmol)
and stirred at r.t. for 16 h. The green solution is then fil-
tered through celite, the filtrate cooled to ꢀ100 ꢁC and
treated with a solution of di(p-tolyl)diazomethane
(14.3 mg, 66 lmol) in dichloromethane (5 ml). The mix-
ture was warmed slowly to r.t. and the solvent was evap-
orated in vacuo to leave a dark residue. This residue was
washed repeatedly with cold pentane and dried to give a
violet solid, which was recrystallised from dichlorometh-
ane/pentane (1/10) at ꢀ60 ꢁC.
Spectroscopic data for 12. (8.4 mg, 29%), m.p. 100 ꢁC
(decomp.). 1H NMR (CD2Cl2):
d 1.08 (t, 6H,
3
3JHH = 7.6 Hz, 2 · CH2CH3), 1.17 (t, 6H, JHH
=
3
7.6 Hz, 2 · CH2CH3), 2.32 (q, 4H, JHH = 7.6 Hz,
2 · CH2CH3), 2.37 (br s, 6H, 2 · terminal CH3), 2.55
3
(q, 4H, JHH = 7.6 Hz, 2 · CH2CH3), 6.62 (br s, 4H,
2 · meso-H + 2 · b-H). 19F NMR (CD2Cl2): d ꢀ76.1
(m). 31P NMR (CD2Cl2): d ꢀ18.0 (tm).
Preparation of cationic TrpyPdIIL complexes as BArF
salts – general procedure. A solution of TrpyPdIIOAcF
(1) or (5) in dichloromethane (25 ml) is treated with
NaBArF (1 eq.) and stirred at r.t. for 16 h. The green
solution is then filtered through celite and the solvent
evaporated in vacuo. The residue is washed several times
with cold pentane and finally dried in vacuo. This resi-
due is redissolved in dichloromethane (25 ml) and trea-
ted with the respective donor reagent at r.t. for
10 min. All volatiles are then removed in vacuo. The res-
idue is washed with several portions of cold pentane,
dried, and recrystallised from dichloromethane/pentane
(1/10) at ꢀ60 ꢁC.
Spectroscopic data for 10. (83.9 mg, 83%), m.p. 56 ꢁC
(decomp.) (C71H56BF24N3PdÆCH2Cl2 requires: C,
53.73; H, 3.63; N, 2.61. Found: C, 53.56; H, 3.84; N,
3
2.67%). 1H NMR (CD2Cl2): d 0.54 (t, 6H, JHH
=
3
7.6 Hz, 2 · CH2CH3), 0.88 (t, 6H, JHH = 7.6 Hz,
2 · CH2CH3), 1.20–1.31 (m, 8H, 4 · CH2CH3), 1.46 (s,
6H, 2 · terminal CH3), 2.45 (s, 6H, 2 · C6H4CH3),
6.72, 6.94 (jeweils s, 4H, 2 · meso-H + 2 · b-H), 7.31
2
(AA0BB0, 8H, JHH = 8.2 Hz, 8 · Haryl), 7.57 (s, 4H,
4 · para-H), 7.73 (s, 8H, 8 · ortho-H). 13C NMR
(CD2Cl2): d 14.2, 16.8, 17.7, 18.1, 20.8, 22.8, 117.9
[s(br),
4 · para-C],
124.5,
124.7,
125.0
(q,
Preparation of methylisonitrilo-(3,4,8,9,13,14-hexa-
ethyl-2,15-dimethyltripyrrinato)-palladium(II) tetrakis-
[3,5-bis(trifluoromethyl)phenyl]borate (13). The title
compound was prepared from TrpyPdIIOAcF (1)
(51.5 mg, 81.0 lmol), NaBArF (71.8 mg, 81.0 lmol)
and excess methylisonitrile according to the general pro-
cedure and yielded a violet solid.
1JCF = 272.1 Hz, 8 · CF3), 129.4 (q, JCF = 31.5 Hz,
8 · meta-C), 130.0 (s, 4 · Caryl), 130.6 (s, 4 · Caryl),
135.3 [s(br), 8 · ortho-C], 136.9, 140.4, 141.5, 149.0,
2
1
152.1, 154.2, 162.1 (q, JBC = 49.9 Hz, 4 · ipso-C),
175.4, 312.5 (s, Pd = C). 19F NMR (CD2Cl2): d ꢀ62.7.
MS (EI, 70 eV): m/z 660 [M ꢀ BArF]+.
Difluorophosphato-(3,4,8,9,13,14-hexaethyl-2,15-di-
methyltripyrrinato)palladium(II) (11). A solution of
TrpyPdIIOAcF (1) (273 mg, 0.43 mmol) in dichloro-
methane (40 ml) is treated with excess sodium fluoro-
phosphate and stirred at r.t. for 16 h. The green
solution is then filtered and the solvent evaporated in va-
cuo. The residue is washed three times with cold pentane
and finally dried in vacuo to yield the title compound as
a violet solid.
Spectroscopic data for 13. (110 mg, 95%), m.p.
87 ꢁC (decomp.) (C62H53BF24N4Pd requires: C, 52.17;
H, 3.74; N, 3.93. Found: C, 52.02; H, 3.84; N,
3
3.62%). 1H NMR (CD2Cl2): d 1.08 (t, 6H, JHH
=
3
7.6 Hz, 2 · CH2CH3), 1.14 (t, 6H, JHH = 7.6 Hz, 2 ·
3
CH2CH3), 1.20 (t, 6H, JHH = 7.6 Hz, 2 · CH2CH3),
3
2.40 (q, 4H, JHH
=
7.6 Hz, 2 · CH2CH3), 2.47 (s,
3
6H, 2 · terminal CH3), 2.59 (q, 8H, JHH = 7.6 Hz,
4 · CH2CH3), 3.41 (br s, 3H, CH3NC), 6.88 (s, 2H,
2 · meso-H), 7.58 (s, 4H, 4 · para-H), 7.74 (s, 8H,
8 · ortho-H). 13C NMR (CD2Cl2): d 14.1, 14.4, 16.6,
17.1, 17.8, 18.4, 18,4, 20.5, 117.8 (m, 4 · para-C),
Spectroscopic data for (11). (224 mg, 78%), m.p.
1
134 ꢁC (decomp.). H NMR (CD2Cl2): d 1.04 (t, 6H,
3
3JHH = 7.6 Hz, 2 · CH2CH3), 1.10 (t, 6H, JHH
=
3
1
7.6 Hz, 2 · CH2CH3), 1,13 (t, 6H, JHH = 7.6 Hz,
2 · CH2CH3), 2.30 (q, 4H, 3JHH = 7.6 Hz, 2 ·
CH2CH3), 2.36 (br s, 6H, 2 · terminal CH3), 2.48, 2.49
121.3, 124.9 (q, JCF = 271.6 Hz, 8 · CF3), 129.2 (q,
2JCF = 31.5 Hz, 8 · meta-C), 135.1 (s, 8 · ortho-C),
137.3, 137.7, 139.1, 139.7, 151.2, 162.1 (q,
1JBC = 49.9 Hz, 4 · ipso-C), 173.1. The signals for the
isonitrile ligand were not detected. 19F NMR
(CD2Cl2): d ꢀ62.7.
3
(2 · q, 8H, JHH = 7.6 Hz, 4 · CH2CH3), 6.59 (br s,
2H, 2 · meso-H). 19F NMR (CD2Cl2): d ꢀ76.8 (m).
31P NMR (CD2Cl2): d ꢀ18.9 (tm). MS (FAB): m/z 522
[M ꢀ PO2F2]+.
Preparation of methylisonitrilo-(3,4,13,14-tetraethyl-
2,15-dimethyltripyrrinato)-palladium(II) tetrakis-[3,5-
bis(trifluoromethyl)phenyl]borate (14). The title
compound was prepared from TrpyPdIIOAcF (5)
(30.0 mg, 51.2 lmol), NaBArF (46.0 mg, 51.2 lmol)
and excess methylisonitrile according to the general pro-
cedure and yielded a violet solid.
Difluorophosphato-(3,4,13,14-tetraethyl-2,15-dimeth-
yltripyrrinato)palladium(II) (12).
A
solution of
TrpyPdIIOAcF (5) (30 mg, 52 lmol) in dichlorometh-
ane (40 ml) is treated with excess sodium fluorophos-
phate and stirred at r.t. for 16 h. The green solution is
then filtered and the solvent evaporated in vacuo. The
residue is washed three times with cold pentane and fi-
nally dried in vacuo to yield the title compound as a
violet solid.
Spectroscopic data for 14. (68.8 mg, 83%), m.p. 82 ꢁC
(decomp.) (C58H45BF24N4Pd requires: C, 50.80; H, 3.31;
1
N, 4.09. Found: C, 50.55; H, 3.22; N, 3.98%). H NMR

M. Bro¨ring et al. / Inorganica Chimica Acta 358 (2005) 3122–3134
3127
3
1
(CD2Cl2): d 1.09 (t, 6H, JHH = 7.6 Hz, 2 · CH2CH3),
124.1, 125.0 (q, JCF = 272.6 Hz, 8 · CF3), 126.8, 129.1
3
2
1.19 (t, 6H, JHH = 7.6 Hz, 2 · CH2CH3), 2.42 (q, 4H,
(q, JCF = 31.5 Hz, 8 · meta-C), 135.2 (br s, 8 · ortho-
C), 138.5, 139.3, 141.0, 151.5, 161.9 (q, JBC = 49.6 Hz,
3JHH = 7.6 Hz, 2 · CH2CH3), 2.50 (s, 6H, 2 · terminal
1
3
CH3), 2.58 (q, 4H, JHH = 7.6 Hz, 2 · CH2CH3), 3.48
4 · ipso-C), 171.6. 19F NMR (CD2Cl2): d ꢀ62.7. 31P
(br s, 3H, CNCH3), 6.75, 6.92 (2 · s, 4H, 2 · meso-H
+ 2 · b-H), 7.57 (s, 4H, 4 · para-H), 7.72 (s, 8H,
8 · ortho-H). 13C NMR (CD2Cl2): d 14.6, 16.5, 18.4,
NMR (CD2Cl2):
d
ꢀ22.5. MS (FAB): m/z 542
[M ꢀ BArF]+, 466 [M ꢀ BArF ꢀ PMe3]+.
Preparation of bis(trimethylphosphino)-(3,4,13,14-
tetraethyl-2,15-dimethyltripyrrinato)palladium(II) tetra-
kis-[3,5-bis(trifluoromethyl)phenyl]borate (18). The
title compound was prepared from TrpyPdIIOAcF (5)
(52.4 mg, 90.3 lmol), NaBArF (79.9 mg, 90.3 lmol)
and trimethylphosphine (18.3 ll, 180.6 lmol) according
to the general procedure and yielded a violet solid.
Spectroscopic data for 18. (121.0 mg, 91%), m.p.
138 ꢁC (decomp.) (C62H60BF24N3P2Pd requires: C,
50.24; H, 4.08; N, 2.84. Found: C, 49.87; H, 4.07; N,
2.96%). 1H NMR (CD2Cl2): d 0.79 (t, 18H, N =
7.6 Hz, 6 · PCH3), 1.08 (t, 6H 3JHH = 7.6 Hz,
18.5, 20.7, 117.8 (m, 4 · para-C), 124.0, 124.9 (q,
1JCF = 271.6 Hz, 8 · CF3), 125.7, 129.1 (q, JCF
=
2
31.5 Hz, 8 · meta-C), 135.2 (s, 8 · ortho-C), 138.4,
1
139.5, 139.7, 151.7, 162.1 (q, JBC = 49.9 Hz, 4 · ipso-
C), 174.3. The signals for the isonitrile ligand were not
detected. 19F NMR (CD2Cl2): d ꢀ62.7.
Preparation of tert-butylamino-(3,4,13,14-tetraethyl-
2,15-dimethyltripyrrinato)-palladium(II) tetrakis-[3,5-
bis(trifluoromethyl)phenyl]borate (15). The title
compound was prepared from TrpyPdIIOAcF (5)
(37.3 mg, 64.3 lmol), NaBArF (57.0 mg, 64.3 lmol)
and tert-butylamine (6.75 ll, 64.3 lmol) according to
the general procedure and yielded a violet solid.
Spectroscopic data for 15. (67.7 mg, 75%), m.p. 84 ꢁC
(decomp.) (C60H53BF24N4Pd requires: C, 51.35; H, 3.81;
3
2 · CH2CH3), 1.16 (t, 6H JHH = 7.6 Hz, 2 · CH2CH3),
3
2.43 (q, 4H, JHH = 7.6 Hz, 2 · CH2CH3), 2.64 (q, 4H,
3JHH = 7.6 Hz, 2 · CH2CH3), 2.81 (s, 6H, 2 · terminal
CH3), 7.04, 7.13 (2 · s, 4H, 2 · meso-H + 2 · b-H),
7.56 (s, 4H, 4 · para-H), 7.72 (s, 8H, 8 · ortho-H). 13C
NMR (CD2Cl2): d 13.6 [t, N = 26.7 Hz, 2 · P(CH3)3],
15.0, 17.5, 18.6, 18.8, 20.3, 117.8 (m, 4 · para-C), 125.0
1
N, 3.99. Found: C, 51.37; H, 3.66; N, 3.66%). H NMR
3
(CD2Cl2): d 1.09 (t, 6H, JHH = 7.6 Hz, 2 · CH2CH3),
3
1.16 (t, 6H, JHH = 7.6 Hz, 2 · CH2CH3), 1.28 [s, 9H,
3
1
C(CH3)3], 2.40 (q, 4H, JHH = 7.6 Hz, 2 · CH2CH3),
(q, JCF = 272.2 Hz, 8 · CF3), 126.3, 126.8, 129.2 (q,
3
2.57 (q, 4H, JHH = 7.6 Hz, 2 · CH2CH3), 2.66 (s, 6H,
2JCF = 31.5 Hz, 8 · meta-C), 135.2 (br s, 8 · ortho-C),
136.2, 139.4, 145.3, 153.2, 161.9 (q, JBC = 49.6 Hz,
1
2 · terminal CH3), 6.85, 6.91 (2 · s, 4H, 2 · meso-
H + 2 · b-H), 7.52 (s, 4H, 4 · para-H), 7.74 (s, 8H,
8 · ortho-H). The signal of the amine hydrogens was
not detected. 13C NMR (CD2Cl2): d 14.2, 14.5, 16.6,
18.3, 18.7, 30.9, 117.9 [s(br), 4 · para-C], 123.6, 125.0
4 · ipso-C), 169.7. 19F NMR (CD2Cl2): d ꢀ62.7. 31P
NMR (CD2Cl2):
d
ꢀ18.4. MS (FAB): m/z 618
[M ꢀ BArF]+, 542 [M ꢀ BArF ꢀ PMe3]+, 466 [M ꢀ
BArF ꢀ 2 PMe3]+.
1
2
(q, JCF = 272.7 Hz, 8 · CF3), 126.9, 129.3 (qq, JCF
=
Preparation of triethylphosphano-(3,4,8,9,13,14-hexa-
ethyl-2,15-dimethyltripyrrinato)-palladium(II) tetrakis-
[3,5-bis(trifluoromethyl)phenyl]borate (19). The title
compound was prepared from TrpyPdIIOAcF (1)
(62.2 mg, 97.8 lmol), NaBArF (86.7 mg, 97.8 lmol)
and excess triethylphosphane according to the general
procedure and yielded a violet solid.
3
31.5 Hz, JBC = 2.9 Hz, 8 · meta-C), 135.2 (br s,
8 · ortho-C), 139.3, 139.7, 140.5, 151.0, 162.2 (q,
1JBC = 49.9 Hz, 4 · ipso-C), 170.7. 19F NMR (CD2Cl2):
d ꢀ62.7.
Preparation of trimethylphosphino-(3,4,13,14-tetra-
ethyl-2,15-dimethyltripyrrinato)-palladium(II) tetrakis-
[3,5-bis(trifluoromethyl)phenyl]borate (17). The title
compound was prepared from TrpyPdIIOAcF (5)
(46.5 mg, 80.2 lmol), NaBArF (71.0 mg, 80.2 lmol)
and trimethylphosphine (8.10 ll, 80.2 lmol) according
to the general procedure and yielded a violet solid.
Spectroscopic data for 17. (106.0 mg, 94%), m.p.
158 ꢁC (C59H51BF24N3PPd requires: C, 50.39; H, 3.66;
Spectroscopic data for 19. (125.0 mg, 85%), m.p.
119 ꢁC (decomp.) (C66H65BF24N3PPd requires: C,
52.69; H, 4.36; N, 2.79. Found: C, 52.77; H, 4.51; N,
1
3
2.66%). H NMR (CD2Cl2): d 0.77 [t(br), 9H, JHH
=
3
7.6 Hz, 3 · PCH2CH3], 1.07 (t, 6H, JHH = 7.6 Hz,
2 · CH2CH3), 1.16 (t, 6H, 3JHH = 7.6 Hz, 2 · CH2CH3),
3
1.19 (t, 6H, JHH = 7.6 Hz, 2 · CH2CH3), 1.61 (m, 6H,
N, 2.99. Found: C, 50.82; H, 3.87; N, 2.88%). 1H
3 · PCH2CH3), 2.42 (q, 4H, JHH = 7.6 Hz, 2 · CH2-
3
3
1.09 (t, 6H, JHH = 7.6 Hz,
3
NMR (CD2Cl2):
d
CH3), 2.66 (q, 4H, JHH = 7.6 Hz, 2 · CH2CH3), 2.69
2 · CH2CH3), 1.17 (t, 6H, 3JHH = 7.6 Hz, 2 · CH2CH3),
(q, 4H, JHH = 7.6 Hz, 2 · CH2CH3), 2.81 (s, 6H,
3
3
1.33 (d, 9H, JHP = 11.4 Hz, 3 · PCH3), 2.43 (q, 4H,
2 · terminal CH3), 7.05 (s, 2H, 2 · meso-H), 7.56 (s,
4H, 4 · para-H), 7.72 (s, 8H, 8 · ortho-H). 13C NMR
(CD2Cl2): d 7.0 (br s, 3 · PCH2CH3), 15.0 (br s,
2 · CH2C H3 + 3 · PC H2CH3), 17.6, 17.7, 18.1, 18.7,
18.9, 21.4, 117.9 (m, 4 · para-C), 123.1, 125.0 (q,
3JHH = 7.6 Hz, 2 · CH2CH3), 2.58 (br s, 4H,
2 · CH2CH3), 2.70 (s, 6H, 2 · terminal CH3), 6.90,
6.97 (2 · s, 4H, 2 · meso-H + 2 · b-H), 7.58 (s, 4H,
4 · para-H), 7.74 (s, 8H, 8 · ortho-H). 13C NMR
1
14.7, 16.7, 17.8 (d, JCP = 28.6 Hz,
2
(CD2Cl2):
d
1JCF = 272.6 Hz, 8 · CF3), 129.3 (q, JCF = 31.6 Hz,
3 · PCH3), 18.4, 18.5, 20.9, 117.9 (m, 4 · para-C),
8 · meta-C), 135.2 (br s, 8 · ortho-C), 135.9, 139.5,

3128
M. Bro¨ring et al. / Inorganica Chimica Acta 358 (2005) 3122–3134
140.6, 143.9, 152.6, 162.2 (q, 1JBC = 49.6 Hz, 4 · ipso-C),
168.4. 19F NMR (CD2Cl2): d ꢀ62.7. 31P NMR
(CD2Cl2): d 0.8. MS (FAB): m/z 640 [M ꢀ BArF]+.
Preparation of triethylphosphano-(3,4,13,14-tetra-
ethyl-2,15-dimethyltripyrrinato)-palladium(II) tetrakis-
[3,5-bis(trifluoromethyl)phenyl]borate (20). The title
compound was prepared from TrpyPdIIOAcF (5)
(43.3 mg, 74.7 lmol), NaBArF (66.2 mg, 74.7 lmol)
and excess triethylphosphane according to the general
procedure and yielded a violet solid.
Preparation of tri-iso-propylphosphano-(3,4,13,14-tet-
raethyl-2,15-dimethyltripyrrinato)palladium(II) tetrakis-
[3,5-bis(trifluoromethyl)phenyl]borate (22). The title
compound was prepared from TrpyPdIIOAcF (5)
(36.0 mg, 62.1 lmol), NaBArF (55.0 mg, 62.1 lmol)
and excess tri-iso-propylphosphane according to the
general procedure and yielded a violet solid.
Spectroscopic data for 22. (84.2 mg, 91%), m.p. 97 ꢁC
(decomp.) (C65H63BF24N3PPd requires: C, 52.38; H,
1
4.26; N, 2.82. Found: C, 51.94; H, 4.29; N, 2.86%). H
Spectroscopic data for 20. (89.9 mg, 84%), m.p.
130 ꢁC (decomp.) (C62H53BF24-N3PPd requires: C,
51.56; H, 3.70; N, 2.91. Found: C, 51.22; H, 3.51;
N, 2.75%). 1H NMR (CD2Cl2): d 0.97–1.05 (m, 9H,
NMR (CD2Cl2): d 1.05–1.19 (m, 30H, 4 · CH2CH3 +
6 · PCHCH3), 2.03–2.09 (m, 3H, 2 · PCHCH3), 2.43
3
(q, 4H, JHH = 7.6 Hz, 2 · CH2CH3), 2.59 (q, 4H,
3JHH = 7.6 Hz, 2 · CH2CH3), 2.83 (s, 6H, 2 · terminal
CH3), 6.94, 7.02 (2 · s, 4H, 2 · meso-H + 2 · b-H),
7.59 (s, 4H, 4 · para-H), 7.76 (s, 8H, 8 · ortho-H). 13C
NMR (CD2Cl2): d 14.7, 16.7, 18.5, 19.2, 19.3, 21.8 (br
s, 6 · PCHCH3), 26.6 (d, 1JCP = 15.3 Hz, 3 · PCHCH3),
3 · PCH2CH3),
1.09
(t,
6H,
3JHH = 7.6 Hz,
2 · CH2CH3), 1.17 (t, 6H, 3JHH = 7.6 Hz, 2 ·
CH2-CH3), 1.61 (m, 6H, 3 · PCH2CH3), 2.42 (q, 4H,
3JHH = 7.6 Hz, 2 · CH2CH3), 2.53 (q, 4H, JHH
=
3
1
7.6 Hz, 2 · CH2-CH3), 2.79 (s, 6H, 2 · terminal
CH3), 6.92, 6.98 (2 · s, 4H, 2 · meso-H + 2 · b-H),
117.9 (m, 4 · para-C), 120.4, 125.0 (q, JCF = 272.7 Hz,
2
3
8 · CF3), 129.3 (qq, JCF = 32.4 Hz, JBC = 2.9 Hz,
8 · meta-C), 135.2 (br s, 8 · ortho-C), 138.4, 138.6,
7.56 (s, 4H, 4 · para-H), 7.72 (s, 8H, 8 · ortho-H).
2
7.7 (d, JPC = 4.8 Hz,
1
13C NMR (CD2Cl2):
d
138.9, 140.2, 150.6, 162.2 (q, JBC = 49.6 Hz, 4 · ipso-
3 · PCH2CH3), 14.7, 16.7, 18.4, 18.5, 19.2 (d,
C), 170.1. 19F NMR (CD2Cl2): d ꢀ62.7. 31P NMR
(CD2Cl2): d 21.8. MS (FAB): m/z 466 [M ꢀ BArF ꢀ
PiPr3]+.
1JPC = 23.8 Hz, 3 · PC H2CH3), 21.0, 21.1, 117.8 (m,
4 · para-C), 123.8, 125.0 (q, 1JCF
=
272.6 Hz,
8 · CF3),
126.7,
129.2
(qq,
2JCF = 31.5 Hz,
3JBC = 2.9 Hz, 8 · meta-C), 135.2 (br s, 8 · ortho-C),
1
138.5, 139.3, 140.8, 151.4, 162.1 (q, JBC = 49.8 Hz,
3. Results and discussion
4 · ipso-C), 171.3. 19F NMR (CD2Cl2): d ꢀ62.7. 31P
NMR (CD2Cl2): d 4.3. MS (FAB): m z 584 [M ꢀ
BArF]+, 466 [M ꢀ BArF ꢀ PEt3]+.
3.1. Formation of cationic TrpyPdII species by anion
exchange
Preparation of tri-iso-propylphosphano-(3,4,8,9,13,14-
hexaethyl-2,15- dimethyltripyrrinato)palladium(II) tet-
rakis-[3,5-bis(trifluoromethyl)phenyl]borate (21). The
title compound was prepared from TrpyPdIIOAcF (1)
(72.5 mg, 110 lmol), NaBArF (101 mg, 110 lmol) and
excess tri-iso-propylphosphane according to the general
procedure and yielded a violet solid.
When the trifluoroacetato complex TrpyPdIIOAcF (1)
[1] is treated with one equivalent of sodium tetrakis-
[3,5-bis(trifluoromethyl)phenyl]borate NaBArF [16] in
dichloromethane solution the ongoing reaction can be
monitored by the separation of a white solid. Following
filtration and extractive work-up the cationic complex 2
is obtained as a violet powder in good yield (Scheme 2).
2 is well soluble in dichloromethane and almost insolu-
ble in pentane. In most other solvents (ethers, aromatics,
nitriles, alcohols), however, 2 is found to decompose
quickly upon dissolution. The cationic tetraethyl deriva-
tive 6 can be prepared analogously from precursor 5 [2],
but the formation of 6 is accompanied with a large
amount of side products, from which the cation can
not be separated. The attempted direct spectroscopic
characterisation of 6 was thwarted by the impurities
and the instability of the compound, so that only indi-
rect evidence of its existence could be gained (see below).
The solvent obviously influences the course of the salt
metathesis. If dichloromethane is exchanged against
1,1,1-trifluorotoluene, the reactions of both 1 and 5 stop
at 50% transformation and yield the dinuclear l-trifluo-
roacetato species [(TrpyPdII)2(l-OAcF)]BArF 7 and
Spectroscopic data for 21. (169 mg, 96%), m.p. 110 ꢁC
(decomp.) (C69H71BF24N3PPd requires: C, 53.59; H,
1
4.67; N, 2.72. Found: C, 51.94; H, 4.29; N, 2.86%). H
NMR (CD2Cl2): d 1.06–1.21 (m, 36H, 6 · CH2CH3 +
6 · PCHCH3), 2.04–2.14 (m, 3H, 3 · PCH CH3), 2.41–
2.45 (m, 4H, 2 · CH2CH3), 2.59-2.69 (m, 8H,
4 · CH2CH3), 2.82 (s, 6H, 2 · terminal CH3), 6.98 (s,
2H, 2 · meso-H), 7.59 (s, 4H, 4 · para-H), 7.76 (s, 8H,
8 · ortho-H). 13C NMR (CD2Cl2): d 14.7, 16.9, 17.4,
18.1, 18.4, 18.5, 19.3, 21.6 (d, 2JCP = 6.8 Hz,
1
6 · PCHCH3), 26.7 (d, JCP = 15.3 Hz, 3 · PCHCH3),
1
117.9 (m, 4 · para-C), 120.4, 125.0 (q, JCF = 272.7 Hz,
2
3
8 · CF3), 129.3 (qq, JCF = 32.4 Hz, JBC = 2.9 Hz,
8 · meta-C), 135.2 (br s, 8 · ortho-C), 138.4, 138.6,
1
138.9, 140.2, 150.6, 162.2 (q, JBC = 49.6 Hz, 4 · ipso-
C), 170.1. 19F NMR (CD2Cl2): d ꢀ62.7. 31P NMR
(CD2Cl2):
d
21.8. MS (FAB): m/z 522 [M ꢀ
BArF ꢀ PiPr3]+.
8 quantitatively as shiny, violet crystals. These

M. Bro¨ring et al. / Inorganica Chimica Acta 358 (2005) 3122–3134
3129
˚
as much as 0.183–0.249 A. These rather large values
are mainly due to the bending of one of the terminal
C4N rings in each TrpyPdII subunit, which in turn ap-
pears to be a sterical requirement for the presence of
the adjacent terminal methyl substituent of the other
TrpyPdII fragment of the respective dinuclear complex.
A distinction between the mono- and dinuclear
TrpyPdII cations 2/6 and 7/8 can also be made by
the different reactivity of the species against diaryldia-
zomethanes. While no reaction is observed between
diphenyl-[17] and di(p-tolyl)diazomethane [18] and the
l-trifluoroacetato compounds 7/8 or the neutral com-
plexes 1/5, the cations 2 and 6 react readily even at
ꢀ100 ꢁC (Scheme 3). From the hexaethyl derivative 2
and di(p-tolyl)diazomethane the structurally character-
ised PdII carbene complex 3 is formed [4]. The NMR
analysis of 3 reveals two highly characteristic resonances
for this type of carbene compounds. In the 13C NMR
spectra a downfield signal at 313.4 ppm unambigously
indicates the presence of a carbene carbon centre in 3.
Scheme 2. Products of salt metathesis reactions of trifluoroacetato
complexes TrpyPdIIOAcF 1 and 5 with NaBArF.
1
compounds can alternatively be prepared by the reac-
tion of 1 or 5 with one half equivalent of NaBArF in
dichloromethane or by the stoichiometric reaction of 1
and 5 with in situ prepared 2 and 6, respectively.
In addition, the H NMR signal for the methyl termini
is found upfield at 1.42 ppm due to the close proximity
of the carbene aromatic rings.
The reaction of 2 with diphenyldiazomethane pro-
ceeds slightly less selective, but nevertheless yields the
respective diphenylcarbene complex 9 as the major
product (>90%), as can be proven by the characteristic
NMR signals at 326.0 ppm (13C) and 1.43 ppm (1H).
The tetraethyl derivative 6 also yields a carbene complex
10 when treated with di(p-tolyl)diazomethane, which is
also the indirect proof for the existence of a cationic
complex 6. 10 shows similar resonances at 312.5 ppm
(13C) and 1.46 ppm (1H) as discussed for 3 and 9. The
reaction of 6 with diphenyldiazomethane, however,
yields mainly decomposed material and no hint for a
PdII carbene complex is found spectroscopically.
What is the true nature of the putative 14VE
[TrpyPdII]+ cations in 2 and 6? Complexes of coordin-
atively unsaturated transition metal cations exhibit a
strong tendency for the coordination of solvent mole-
cules. The use of dichloromethane as a ligand has been
observed rather frequently, and several respective com-
plexes were structurally characterised in the past
[19–28]. The combustion analysis of 2 indicates the pres-
ence of one molecule of dichloromethane per formula
unit. Unfortunately, however, dichloromethane has
frequently been found by us in the crystal lattice of par-
ticularly the BArF salts of TrpyPdII cations. A thermo-
gravimetric analysis of 2 shows no loss of any volatile
compound before the decomposition begins at 87 ꢁC.
This behaviour hints to either the absence or the coordi-
native binding of dichloromethane. Although many at-
tempts were undertaken, no single crystal could be
The NMR spectroscopic data of the mononuclear
complex 2 and the dinuclear complexes 7 and 8 are char-
acteristically different from each other. The singlet for
1
the terminal methyl protons appears in the H NMR
of 2 at 2.55 ppm and is shifted markedly to 2.11 and
2.16 ppm, respectively, for 7 and 8. Additionally, the
19F NMR spectra of the dinuclear species 7 and 8 show
two singlets at ca. ꢀ63 and ꢀ73 ppm with relative inten-
sities of 24 and 3, while only one signal appears for 2 at
ꢀ62.7 ppm.
Both [(TrpyPdII)l-OAcF]BArF complexes 7 and 8
grew single crystals by slow diffusion of pentane into
dichloromethane solutions at ꢀ60 ꢁC, which were ana-
lysed by X-ray diffraction. The molecular structures of
7 and 8 are shown in Fig. 1. Table 2 summarises selected
bond lengths and bond angles. In the case of 7, one mol-
ecule of dichloromethane per formula unit was found to
stabilise the crystal lattice.
The crystallographic analyses confirm the dinuclear
molecular structure of both complexes. The TrpyPdII
subunits appear stacked on each other, resulting in
˚
Pd(1)ꢁ ꢁ ꢁPd(2) distances of 3.165 (7) and 3.412 A (8),
respectively. These distances are too long for any bond-
ing or attractive interaction between the two metal ions.
The close arrangement of the PdII atoms must rather be
regarded as a sterical necessity.
The projections through the Pdꢁ ꢁ ꢁPd axes in Fig. 1
show, that the two TrpyPdII subunits in 7 and 8 are
rotated against each other by 25.5ꢁ and 45.5ꢁ, so that
the complexes display semi-staggered and staggered con-
formations, respectively. The C14 perimeter of all
TrpyPdIIO units in 7 and 8 deviate from planarity by
obtained from 2. Our efforts to prepare similar
ꢀ
derivatives with the weakly coordinating BF4
ꢀ
,
ꢀ
Al½OCHðCF3Þ ꢃ and Al½OCðCF3Þ ꢃ anions [29] by
2
3
4
4

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M. Bro¨ring et al. / Inorganica Chimica Acta 358 (2005) 3122–3134
Fig. 1. Molecular structures of the cations of [(TrpyPdII)2OAcF]BArF 7 (left) and 8 (right) in the crystal. Top: ORTEP-plot, side view. Bottom: ball-
and-stick-plot, projections through the Pd(1)ꢁ ꢁ ꢁPd(2) axes (without alkyl substituents).
The solution structure of 2 was investigated by tem-
perature dependent NMR methods. Down to 183 ꢁC
no interaction of the TrpyPdII cation with either the
BArF anion or the CD2Cl2 solvent was observed [30].
The possible agostic interaction of a three coordinate
14VE cation with the adjacent methyl groups was ruled
out by a proton coupled low-temperature 13C NMR
experiment (Fig. 2) [31]. In case of a metal–hydrogen
contact the hydride character of the hydrogen atom is
enforced, and the methyl group becomes more like a
methylene unit. The result is a decrease of the 1JCH cou-
pling constant with temperature. For 2 the coupling
constant is found at the temperature independent value
of 129 Hz, which is in perfect agreement with a normal
and untouched CH3 group. The NMR experiments
Scheme 3. Reactivity of TrpyPdII species 1,2, and 5–8 against
point to the presence of a coordinatively saturated
diaryldiazoalkanes.
16VE PdII ion. A kinetically highly labile dichlorometh-
ane complex is thus the best estimation for 2. This inter-
pretation also confirms the low stability of 2 in solvents
other than dichloromethane.
salt metathesis were hampered by the insufficient solu-
bility of the respective sodium and/or lithium salts in
dichloromethane and either yielded dinuclear species
similar to 7 and 8 or failed completely. The action of sil-
ver salts on TrpyPdII halides leads to the immediate
decomposition of the precursors only. Therefore the sit-
uation in the solid state remains unresolved.
An alternative interpretation of the observations de-
scribed above is the presence of a very labile bound aquo
ligand in 2 and 6. As for dichloromethane such a ligand
would be hard to identify spectroscopically. In addition,
ꢀ
the partial hydrolysis of PF6 and selective formation of

M. Bro¨ring et al. / Inorganica Chimica Acta 358 (2005) 3122–3134
3131
Fig. 2. Details from the alkyl region of the proton coupled 13C NMR spectrum of 2 in CD2Cl2 at 183 K. The quartet of the methyl termini is
highlighted.
the difluorophosphate derivatives 11 and 12 upon treat-
ment of 1 and 5 with sodium hexafluorophosphate
(Scheme 4) points to a water activation process during
the reaction. Literature precedents for similar hydrolytic
reactions are known [32–36].
In the sum of all investigations it appears most likely,
that 2 and 6 constitute cationic, distorted square-planar
16VE PdII complexes with one extremely weak bound
donor ligand, which is either dichloromethane or water,
depending on the environment.
The experiments employing ligands of the classes
N-oxide, alcohol, ether, cyclic ether and nitrile, almost
all amines and non-tertiary phosphanes lead to the
quick decomposition of the starting material. Defined
products with a sufficient stability for isolation were
only available with the ligands methylisonitrile, trialkyl-
phosphane (alkyl = methyl, ethyl, i-propyl) and in one
case with tert-butylamine. All products were received
by direct crystallisation from the reaction mixtures.
Scheme 5 summarises the successful attempts. Com-
pounds 4 and 16 have been described previously [5]
and are included for comparison.
All new complexes were characterised mainly by
NMR methods. In some cases, especially for the more
robust phosphane derivatives, mass spectra and com-
bustion analyses could also be obtained. It is a striking
fact, that five coordinate species are formed only among
the trimethylphosphine complexes. The spectroscopic
data of 18 closely resemble those of the known hexaethyl
derivative 4.
The compounds 13 (L = CH3NC), 15 (L = tBuNH2)
and 17 (L = PMe3) were analysed by single crystal
X-ray diffraction. Crystals of 13 were grown by slow
diffusion of pentane into a dichloromethane solution
containing excess methylisonitrile at ꢀ30 ꢁC. The mea-
surement of 13 was carried out at ꢀ50 ꢁC. 15 and 17
were crystallised by slow diffusion of pentane into
dichloromethane solutions at ꢀ60 ꢁC. The molecular
structures of the cations of 13, 15 and 17 are given in
Figs. 3–5, respectively. Selected structural parameters
are presented in Table 3.
3.2. Ligand association reactions and the formation of five
coordinate species
The observation of a pentacoordinate PdII complex
[TrpyPdII(PMe3)2]BArF 4 stable in solution and in the
solid state [5] may be qualitatively explained if one con-
siders, that the release of strain in the tetracoordinate
monophosphine precursor [TrpyPdIIPMe3]+ provides
sufficient energy to overcome the repulsion between
the electron pair of the fifth donor and the occupied
dz2 orbital of the PdII ion. Such an interpretation would
leave much opportunity to observe five coordinate
TrpyPdII complexes with a variety of external ligands.
In order to investigate the scope and limitation of the
formation of pentacoordinate PdII complexes with the
tripyrrin ligands, the cationic 2 and 6 were treated with
different C-, N-, O- and P donor ligands. A surprisingly
low stability of the compounds was generally observed.
The result of the structural analysis of 13 reveals with
a Pd(1)–C(29)–N(4) angle of 166.7(2)ꢁ and a C(29)–
N(4)–C(30) angle of 176.9(3)ꢁ an almost linear coordi-
nation of the methylisonitrile ligand to the PdII ion.
The N(2)–Pd(1)–C(29) angle of 159.09(9)ꢁ and the dis-
˚
tances C(1)ꢁ ꢁ ꢁC(29) of 3.032 A and C(16)ꢁ ꢁ ꢁC(29) of
˚
2.940 A are indicative for a pseudoplanar coordination
˚
environment of the metal centre. With 1.949(3) A the
Scheme 4. Formation of the difluorophosphate complexes 11 and 12.

3132
M. Bro¨ring et al. / Inorganica Chimica Acta 358 (2005) 3122–3134
R
R
PMe3
L (excess)
or
PMe3 (1 eq)
R
N
R
N
PMe3 (excess)
N
2 or 6
Pd
Pd
L
N
N
N
PMe3
BArF
BArF
13 (R = Et, L = MeNC)
14 (R = H, L = MeNC)
15 (R = H, L = tBuNH2)
16 (R = Et, L = PMe3)
17 (R = H, L = PMe3)
19 (R = Et, L = PEt3)
20 (R = H, L = PEt3)
21 (R = Et, L = PiPr3)
22 (R = H, L = PiPr3)
4 (R = Et)
18 (R = H)
Scheme 5. Preparation of cationic TrpyPdIIL species as BArF salts 13–17 and 19–22 and of pentacoordinate complexes 4 and 18.
Pd(1)–C(29) bond of 13 is found in the typical range for
related cationic isonitrile compounds [37–41].
As in 13 the central PdII ion of 15 is coordinated in a
pseudoplanar fashion. The voluminous tert-butyl substi-
tuent of the amino ligand is situated as distant from the
tripyrrolic perimeter as possible. The two amine pro-
tons, which were located in the difference Fourier map
and refined with free Ueq, are therefore pointing directly
towards both methyl termini of 15 with the result of a
bend in the coordinating environment by ca. 24ꢁ. The
amino ligand appears to be only weakly bound. The
˚
Pd–N(4) distance of 2.101(4) A is at the upper limit of
what is known for alkylamine–PdII complexes [42,43].
Three methyl groups effectively shield the amine
Fig. 4. ORTEP plot of the molecular structure of the cation of
[TrpyPdII(tBuNH2)]BArF 15.
Fig. 3. ORTEP plot of the molecular structure of the cation of
[TrpyPdII(CNMe)]BArF 13.
Fig. 5. ORTEP plot of the molecular structure of the cation of
[TrpyPdIIPMe3]BArF 17.

M. Bro¨ring et al. / Inorganica Chimica Acta 358 (2005) 3122–3134
3133
hydrogen atoms, so that no hydrogen bonds to adjacent
molecules in the crystal of 15 can be formed for sterical
reasons.
The PdII ion of the trimethylphosphine derivative 17
also resides in the expected pseudoplanar coordination
environment. With angles N(1)–Pd–N(3) of 169.45(8)ꢁ
and N(2)–Pd–P(1) of 143.20(6)ꢁ the deviation of the cen-
tral N3PdD subunit from planarity is the largest in this
species. The growing steric influence in the series of tri-
alkylphosphanes also results in decreasing bond
strengths, as anticipated for compounds with severe
out-of-plane distortions. As we disclosed by NMR
experiments, triethylphosphane cleanly displaces tri-
iso-propylphosphane from the coordination sphere of
the PdII ion in 21, but is in turn immediately replaced
by trimethylphosphine. Within the examined system,
the phenomenon of pentacoordination of PdII appears
as a delicate energetic balance between the size of the
donor ligand L and the induced out-of-plane distortion
of the TrpyPdII subunit. Although structural informa-
tion for the compounds 19–22 are still missing, it is very
probable, that pentacoordination can be observed in
palladium tripyrrins only with L = PMe3.
˚
study. The distances C(1)ꢁ ꢁ ꢁC(27) of 3.495 A and
˚
C(16)ꢁ ꢁ ꢁC(27) of 3.429 A are smaller than the sum of
the van der Waals radii and indicate the highly strained
nature of this molecular ion. Interestingly, the Pd–P
˚
bond length of 2.3136 A shows no particular elongation.
The overall structure of the [TrpyPdIIPMe3]+ cation of
17 strongly resembles that of the recently published
compound 16.
From Table 4 it can be deduced, that within the
group of tetracoordinate cationic TrpyPdIIL complexes
a correlation exists between the size of the donor ligand
4. Supplementary material
1
L and the downfield shift of the H NMR signal of the
Crystallographic data for the structural analysis have
been deposited with the Cambridge Crystallographic
Data Centre, CCDC Nos. 218911 (7), 218915 (8),
218914 (13), 218912 (15) and 218913 (17). Copies of this
information may be obtained free of charge from The
Director, CCDC, 12 Union Road, Cambridge, CB2
1E2, UK (fax: +44 1223 336 033; email: deposit@ccdc.
cam.ac.uk, www: http://www.ccdc.cam.ac.uk).
methyl termini. Additionally it becomes apparent, that
the deviation from the planarity of the N3PdD subunit
and with it the intramolecular strain grows with the size
of the donor ligand L. Below a certain size and amount
of strain, no five coordinate species are observed. This is
in accord with the consideration from above, that the re-
lease of strain in the tetracoordinate precursor com-
plexes [TrpyPdIIL]+ upon binding a fifth donor has to
provide sufficient energy to overcome the repulsion be-
tween this donor and the PdII ion.
Acknowledgements
With the growing size of the ligand L an increased
out-of-plane binding situation within the TrpyPdII unit
is observed. This trend is visible in the development of
the Nterm–Pd–D angle (Table 4), and it is very likely, that
the formation of a square-pyramidal structure is increas-
ingly disfavoured with large ligands, that pull the PdII ion
out of the tripyrrin plane. This scenario seems to be
present with the trialkylphosphanes and might well
be responsible for the fact, that no ligand larger than
PMe3 can produce pentacoordinate [TrpyPdIIL2]+
Funding was kindly provided by the Deutsche For-
schungsgesellschaft and the Fonds der Chemischen
Industrie. Support from Prof. Dr. Dr. h.c. Helmut Wer-
ner (Wurzburg) is gratefully acknowledged.
¨
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