Organoplatinum complexes with an ester substituted bipyridine ligand: Oxidative addition and supramolecular chemistry

Article abstract of DOI:10.1016/j.jorganchem.2012.10.037

The synthesis and chemistry of the complex [PtMe₂(bebipy)], 1, where bebipy = 4,4′-bis(ethoxycarbonyl)-2,2′-bipyridine, are described. Complex 1 reacted with HCl to give [PtClMe(bebipy)] and [PtCl ₂(bebipy)], and all of these platinum(II) complexes gave π-stacking in the solid state. Complex 1 reacted with X₂ by trans oxidative addition to give [PtX₂Me₂(bebipy)], X = Br, I, OH, and the complex with X = I is characterized by structure determination as [PtI₂Me₂(bebipy)].1.5I₂. Complex 1 usually reacted with RX by trans oxidative addition, to give [PtXRMe₂(bebipy) ], R = Me, X = I; R = CO₂Et, X = Cl; R = CH₂CO ₂H, X = Br; R = CH₂-4-C₆H₄-CO ₂H, X = Br; R = CH₂-4-C₆H₄-CH ₂CO₂H, X = Br; R = CH₂CONHC₆H ₅, X = Br; R = CH₂CONH-4-C₆H₄-t-Bu, X = Br; R = CH₂-3-C₆H₄-CH₂OH, X = Br. However, acetyl chloride reacted to give a mixture of compounds formed by cis and trans oxidative addition, and it is suggested that the reaction occurs by initial nucleophilic attack by platinum(II) at the carbonyl group with formation of a tetrahedral intermediate [Pt⁺Me ₂(CMeClO^-)(bebipy)]. The platinum(IV) complexes with hydrogen bonding groups formed supramolecular dimers or polymers in the crystalline state, but the ester groups of the bebipy ligands did not participate in the hydrogen bonding.

Full text of DOI:10.1016/j.jorganchem.2012.10.037

Journal of Organometallic Chemistry 724 (2013) 7e16
Contents lists available at SciVerse ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Organoplatinum complexes with an ester substituted bipyridine ligand: Oxidative
addition and supramolecular chemistry
*
Muhieddine Safa, Richard J. Puddephatt
Department of Chemistry, University of Western Ontario, London, Canada N6A 5B7
a r t i c l e i n f o
a b s t r a c t
The synthesis and chemistry of the complex [PtMe2(bebipy)], 1, where bebipy ¼ 4,40-bis(ethoxycarbonyl)-
Article history:
2,20-bipyridine, are described. Complex 1 reacted with HCl to give [PtClMe(bebipy)] and [PtCl2(bebipy)],
Received 25 September 2012
Received in revised form
22 October 2012
and all of these platinum(II) complexes gave p-stacking in the solid state. Complex 1 reacted with X2 by
trans oxidative addition to give [PtX2Me2(bebipy)], X ¼ Br, I, OH, and the complex with X ¼ I is charac-
terized by structure determination as [PtI2Me2(bebipy)].1.5I2. Complex 1 usually reacted with RX by trans
oxidative addition, to give [PtXRMe2(bebipy)], R ¼ Me, X ¼ I; R ¼ CO2Et, X ¼ Cl; R ¼ CH2CO2H, X ¼ Br;
R ¼ CH2-4-C6H4-CO2H, X ¼ Br; R ¼ CH2-4-C6H4-CH2CO2H, X ¼ Br; R ¼ CH2CONHC6H5, X ¼ Br;
R ¼ CH2CONH-4-C6H4-t-Bu, X ¼ Br; R ¼ CH2-3-C6H4-CH2OH, X ¼ Br. However, acetyl chloride reacted to
give a mixture of compounds formed by cis and trans oxidative addition, and it is suggested that the
reaction occurs by initial nucleophilic attack by platinum(II) at the carbonyl group with formation of
a tetrahedral intermediate [PtþMe2(CMeClOꢀ)(bebipy)]. The platinum(IV) complexes with hydrogen
bonding groups formed supramolecular dimers or polymers in the crystalline state, but the ester groups of
the bebipy ligands did not participate in the hydrogen bonding.
Accepted 24 October 2012
Keywords:
Oxidative addition
Platinum
Bipyridine
Supramoleculat
Ó 2012 Elsevier B.V. All rights reserved.
1. Introduction
derivatives have been studied as sensitizers for electron transfer or
as catalysts [26,27,28,29,30]. Complex 1 was expected to be less
The complexes of formula [PtMe2(NN)], where NN is a chelating
nitrogen donor ligand such as 2,20-bipyridine [1,2], react with alkyl
halides, RX, to give platinum(IV) complexes [PtXMe2R(NN)] by
oxidative addition [3,4,5]. These reactions have been used to
prepare a wide range of functional organoplatinum(IV) complexes
[3,6,7,8,9,10,11,12,13,14,15,16,17], and several of them have served as
paradigms for understanding reactivity and mechanism in oxidative
addition reactions [3,18,19,20,21,22,23]. Several substituted deriva-
tives of 2,20-bipyridine have been studied, most commonly by
introducing alkyl groups to increase solubility of the complexes
[PtMe2(NN)], such as in A (Chart 1) [3,24]. However, functional
groups have also been used as in complexes B and C (Chart 1) to allow
formation of polymers or oligomers through either covalent bond
formation with B or hydrogen bond formation with C [15,17,24,25].
This article describes the synthesis and chemistry of the
complex [PtMe2(bebipy)], 1 (Chart 1), where bebipy ¼ 4,40-bis(e-
thoxycarbonyl)-2,20-bipyridine [26]. The ligand 2,20-bipyridine-
4,40-dicarboxylic acid has often been used to anchor transition
metal catalysts to oxide supports, and complexes of its ester
electron rich, and so less reactive in oxidative addition, than
[PtMe2(bipy)], because the ethoxycarbonyl groups are electron
withdrawing substituents, but there is potential for the ester
groups to participate in some reactions. For example, they can act as
hydrogen bond acceptors [8,26,27,28,29,30].
2. Results and discussion
2.1. Synthesis and structure of square planar complexes
Three square planar platinum(II) complexes with the ligand
bebipy were prepared according to Scheme 1. Complex 1 was
prepared as a purple solid by reaction of the ligand bebipy with
[Pt2Me4(
m-SMe2)2] with displacement of the weakly bound dime-
thylsulfide ligands. In the 1H NMR spectrum of complex 1, the
methylplatinum resonance occurred at
d
¼ 1.14, with coupling
2JPtH ¼ 86 Hz, while the ortho pyridyl protons occurred at
d
¼ 9.42,
3
with coupling JPtH ¼ 28 Hz. Only one set of pyridyl and ethyl
resonances was observed as expected for a complex with effective
C2v symmetry. The reaction of complex 1 with HCl gave complexes
2 and 3, with loss of methane in each step. The 1H NMR spectrum of
complex 3 contained no methylplatinum resonance and the ortho
* Corresponding author. Fax: þ519 661 3022.
E-mail address: pudd@uwo.ca (R.J. Puddephatt).
3
pyridyl protons occurred at
d
¼ 9.97, with coupling JPtH ¼ 48 Hz.
0022-328X/$ e see front matter Ó 2012 Elsevier B.V. All rights reserved.
http://dx.doi.org/10.1016/j.jorganchem.2012.10.037

8
M. Safa, R.J. Puddephatt / Journal of Organometallic Chemistry 724 (2013) 7e16
Chart 1. Some derivatives of [PtMe2(bipy)].
The higher coupling constant compared to that in 1 is a result of the
lower trans influence of the chloride ligands in 3 compared to the
methyl ligands in 1.
The molecular structures of complexes 1e3 were determined
and are shown in Fig. 1. In each case, there are two non-equivalent
molecules in the unit cell and, for the unsymmetrical complex 2
there is also disorder of the methyl and chloride ligands which
caused the refinement of the structure to be difficult. The Pt(1) and
Pt(2) molecules in 2 were refined to have 85:15 and 60:40 occu-
pation respectively, and only the major components are shown in
Fig. 1. The coordination geometries of the complexes are similar,
with the mean PteN distance in 1 being slightly higher and the
NPtN angle slightly lower in 1 compared to 3 [mean PteN ¼ 2.08 Å
in 1, 2.04 Å in 3; mean NePteN ¼ 78.1ꢁ in 1, 79.9ꢁ in 3], as a result of
the higher trans influence of methyl compared to chloride.
One notable feature of the structures is that the conformations of
the ester groups are varied (Fig. 1). The CO2 unit of each ester group
tends to be roughly coplanar with the attached pyridyl group,
presumably because this allows a higher degree of conjugation. The
carbonyl group may be directed towards (endo conformation) or
away (exo conformation) from the plane which bisects the two
pyridyl groups. In complex 1 the two ester groups for the Pt(1) and
Pt(2) molecules are in the endo,endo and endo,exo conformation
respectively, while in complex 3 the two ester groups for both the
Pt(1) and Pt(2) molecules are in the exo,exo conformation (Fig. 1).
The Pt(1) and Pt(2) molecules of the unsymmetrical complex 2 have
Fig. 1. The molecular structures of: top, two inequivalent molecules of 1; center, two
inequivalent molecules of 2, showing only the major component due to Me/Cl disorder
in each case; bottom, one of the two inequivalent molecules of 3 (the second is very
similar).
the endo,exo and exo,exo conformation, with the major component
of the Pt(1) molecule having the endo conformation trans to the
methyl group and the exo conformation trans to the chloride ligand.
We have carried out DFT calculations for all of the possible
conformers for each molecule, and find that the calculated gas phase
energies are equal within 2 kJ molꢀ1 in each case. It is likely,
therefore, that the observed conformations arise through crystal
packing or weak intermolecular secondary bonding forces.
The molecules of complexes 1e3 pack in columns, as shown in
Figs. 2e4, a form of packing which is common for planar molecules
[31,32,33,34]. Complex 1 packs with alternating Pt(1) and Pt(2)
molecules as [Pt(1)Pt(2)]n (Fig. 2), while complexes 2 and 3 pack
Scheme 1. Synthesis of platinum(II) complexes.

M. Safa, R.J. Puddephatt / Journal of Organometallic Chemistry 724 (2013) 7e16
9
Fig. 4. Stacking of molecules of complex 3.
Scheme 2. The 1H NMR spectra of complexes 4e6 each contained
2
a single methylplatinum resonance [4,
d
¼ 2.07, JPtH ¼ 71 Hz; 5,
Fig. 2. Stacking of molecules of complex 1.
d
¼ 2.42, 2JPtH ¼ 73 Hz; 6,
d
¼ 1.66, 2JPtH ¼ 70 Hz], and a single set of
pyridyl and ethyl resonances, as expected for a complex with C2v
symmetry. The low value of the coupling constant 3JPtH for the ortho
pyridyl protons in 4e6 [3JPtH ¼ 18 Hz in each case] shows that the
pyridyl groups are trans to methyl groups.
in pairs of equivalent molecules, as [Pt(1)Pt(1)Pt(2)Pt(2)]n (Figs. 3
and 4).
2.2. Oxidative addition reactions of complex 1 with halogens and
hydrogen peroxide
The structure of complex 4 is shown in Fig. 5, and confirms that
it is formed by trans oxidative addition of bromine. In complex 4,
the ester groups adopt the endo,exo conformation. The reaction of
complex 4 with bromine occurred very rapidly and was monitored
by 1H NMR spectroscopy in CD2Cl2 solution. At ꢀ80 ꢁC, complex 4
was already present, but an intermediate was also observed in
The reaction of bromine, iodine or hydrogen peroxide to
complex 1 occurred by trans oxidative addition, as shown in
which the methylplatinum resonance occurred at
d
¼ 1.97, with
2JPtH ¼ 70 Hz. This resonance decayed on warming the solution, and
4 was formed as the sole product. The intermediate is tentatively
identified as the bromine complex, D with X ¼ Br, as shown in the
mechanism of Scheme 3. The mechanism is consistent with that
proposed for oxidative addition of halogens and hydrogen peroxide
to [PtMe2(bipy)] [35,36,37,38,39,40,41], and the NMR spectrum of
the intermediate is similar to that of the analogous iodine complex
[PtMe2(I2)(bipy)] [35].
Complex 5 was difficult to crystallize but good crystals were
finally obtained from a reaction of complex 1 with excess iodine.
The structure is shown in Fig. 6, which shows the trans-PtI2
Fig. 3. Stacking of molecules of complex 2.
Scheme 2. Oxidative addition of bromine, iodine and hydrogen peroxide.

10
M. Safa, R.J. Puddephatt / Journal of Organometallic Chemistry 724 (2013) 7e16
Fig. 5. The structure of complex 4. Selected bond parameters: PteN(11) 2.17(1); Pte
N(22) 2.17(1); PteC(1) 2.17(1); PteC(2) 2.10(1); PteBr(1) 2.405(2); PteBr(2) 2.437(2) Å.
stereochemistry, the presence of extra iodine molecules and the
endo,endo conformation of the ester groups. The association of
platinum(IV) iodide complexes with molecular iodine has been
observed previously [35,40,41], but the arrangement in complex
5.1.5I2 appears to be unprecedented. The atom I(2) is associated
with one iodine molecule, with distances I(2)/I(3) ¼ 3.245(1) and
I(3)eI(4) ¼ 2.7327(7) Å, while a second iodine molecule bridges
between the I(1) atoms of neighboring molecules of complex 5,
with I(1)/I(5) ¼ 3.407(1) and I(5)eI(5A) ¼ 2.748(1) Å. The complex
could be considered to contain an Iꢀ3 ligand and a bridging I24ꢀ
ligand, but the distances suggest only secondary bonding between
the iodine molecules and iodide ligands [35,40,41,42,43,44].
The oxidative addition of hydrogen peroxide to complex 1 to
give the dihydroxo complex 6 (Scheme 2) is similar to reactions
with similar complexes [PtMe2(NN)] [37,38,39,45], but with one
unusual feature. Complex 6 was formed in high yield but it
decomposed in solution to give the free ligand bebipy, with
Fig. 6. The structure of complex 5.1.5I2: Selected bond distances: PteN(11) 2.179(5);
PteN(22) 2.171(5); PteC(1) 2.119(6); PteC(2) 2.104(7); PteI(1) 2.6376(5); PteI(2)
2.6421(5); I(3)eI(4) 2.7327(7); I(5)eI(5A) 2.748(1) Å.
precipitation of [{PtMe2(OH)2}n] as a white solid. The reaction was
complete in two days at room temperature, and the polymeric
complex [{PtMe2(OH)2}n] was isolated and identified by dissolving
in dilute D2SO4/D2O to give the characteristic NMR spectrum of the
2
cation cis-[PtMe2(OD2)4]2þ with
d
(MePt) ¼ 2.26, JPtH ¼ 66 Hz
[46,47,48]. The easy dissociation of the bebipy ligand from complex
6 is probably a result of the electron withdrawing properties of the
carboxylic ester substituents, which make bebipy a weaker donor
than the parent 2,20-bipyridine.
2.3. Oxidative addition reactions of complex 1 with carbone
halogen bonds
The oxidative addition reactions of some compounds with
carbonehalogen bonds to complex 1 are illustrated in Scheme 4.
Methyl iodide reacted rapidly with 1 to give [PtIMe3(bebipy)], 7.
This complex was readily characterized by its 1H NMR spectrum,
which contained two methylplatinum resonances in a 1:2 ratio at
d
¼ 0.60, 2JPtH ¼ 72 Hz, and
d
¼ 1.52, 2JPtH ¼ 71 Hz, corresponding to
the methyl groups trans to iodide and nitrogen respectively. The
reaction with CD3I occurred by trans oxidative addition. Similarly,
ethyl chloroformate reacted with 1 by trans oxidative addition to
give complex 8 (Scheme 4). The 1H NMR spectrum of 8 contained
only a single methylplatinum resonance at
d
¼ 1.65, 2JPtH ¼ 74 Hz, as
expected for a complex with Cs symmetry. Complex 8 decomposed
slowly in solution to give [PtClMe(bebipy)], 2, by reductive elimi-
nation of ethyl acetate.
The reaction of acetyl chloride with complex 1 gave [PtClMe2(-
COMe)(bebipy)], as a mixture of the products of trans and cis
oxidative addition 9a and 9b in a 25:75 ratio. The cis isomer 9b was
characterized in the 1H NMR spectrum by the presence of two equal
intensity methylplatinum resonances at
d
¼ 0.75, 2JPtH ¼ 74 Hz, and
Scheme 3. Proposed mechanism of formation of complexes 4e6.
1.57, 2JPtH ¼ 72 Hz. The resonance for the methyl group of the acetyl

M. Safa, R.J. Puddephatt / Journal of Organometallic Chemistry 724 (2013) 7e16
11
complexes can also occur with trans stereochemistry, though in
many cases the stereochemistry of oxidative addition cannot be
determined [54,55]. The reductive elimination of acetyl iodide or
acetic anhydride is a key step in the Monsanto and Cativa processes
for manufacture of acetic acid, and has been proposed to occur
with cis stereochemistry [56,57]. The oxidative addition occurs by
nucleophilic attack by the electron-rich platinum(II) complex 1 and
so there is an analogy to the mechanism of nucleophilic substitu-
tion at a trigonal carbon center, which occurs by the additione
elimination mechanism involving
a tetrahedral intermediate,
MeClNuCOꢀ, where Nuꢀ is the nucleophile, followed by elimina-
tion of the chloride ion to give the product [58]. In the reaction
with complex 1, the initial tetrahedral intermediate would be F
(Scheme 5), but this cannot rearrange directly to either 9a or 9b. To
give the product of trans oxidative addition, chloride elimination
must occur to give G and then chloride coordination can occur to
give 9a. By analogy with the nucleophilic substitution mechanism
[58], this could be termed an additioneeliminationecoordination
mechanism. Complex 8 is probably formed in an analogous way
from 1 and ethyl chloroformate (Scheme 4). The formation of 9b
requires a Berry pseudorotation step within a 5-coordinate plati-
num(IV) intermediate [59,60]. The isomerization of 9a to 9b
probably involves dissociation of the chloride ligand to regenerate
intermediate G, which can rearrange to H followed by chloride
coordination to give 9b. However, 9b can also be formed by rear-
rangement of the initially formed intermediate F to give I, which can
undergo intramolecular chloride ion migration to give 9b. This more
direct formation of 9b could be termed an additionepseudorotatione
Scheme 4. Oxidative addition of carbonehalogen bonds.
3
ligand occurred at
d
¼ 2.58. JPtH ¼ 10 Hz. On the other hand, the
trans isomer 9a was identified by the presence of only one meth-
ylplatinum resonance in the 1H NMR spectrum at
d
¼ 1.59,
2JPtH ¼ 72 Hz, and the acetyl group resonance was at
d
¼ 2.00,
3JPtH ¼ 14 Hz. Once isolated, the complex was stable in solution at
room temperature, and the ratio of the isomers 9a:9b did not
change with time. The structure of the major isomer 9b was
determined and is shown in Fig. 7. In the unsymmetrical complex
formed by overall cis oxidative addition, the complex is chiral at
platinum, but the lattice contains a racemic mixture of the C and A
enantiomers. The PteC distance to the acetyl group is slightly
shorter than those to the two methyl groups (Fig. 7). The ester
groups adopt the endo,endo conformation.
The reaction of complex 1 with acetyl chloride in CD2Cl2 solu-
tion was monitored by 1H NMR spectroscopy. The reaction
occurred rapidly at room temperature and gave an initial ratio of
9a:9b of 50:50 which changed to 25:75 after one day, and then
remained constant indicating that equilibrium was reached. No
further intermediates were detected when the reaction was
monitored at low temperature, the initial ratio of 9a:9b being
roughly 50:50. Thus, the initial reaction gives a mixture of isomers
and then a slower isomerization occurs, favoring the product of cis
oxidative addition at equilibrium. Previous examples of oxidative
addition of acetyl chloride with organoplatinum(II) complexes
have been shown to occur more selectively by trans oxidative
addition [49,50,51,52,53]. Oxidative addition to rhodium(I)
Fig. 7. The structure of the A enantiomer of complex 9b. Selected bond parameters:
PteN(11) 2.177(5); PteN(22) 2.184(5); PteC(1) 2.068(6); PteC(2) 2.072(6); PteC(3)
2.026(6); PteCl 2.437(1) Å.
Scheme 5. Possible mechanisms of formation and isomerization of 9a and 9b.

12
M. Safa, R.J. Puddephatt / Journal of Organometallic Chemistry 724 (2013) 7e16
migration mechanism (Scheme 5), and is likely to be responsible for
the cis product that is formed by kinetic control.
E kJ/mol
400
H + Cl-
G + Cl-
The structures of the complexes of Scheme 5, as calculated by
DFT in the gas phase, are shown in Fig. 8 and the corresponding
energies are in Fig. 9. The reaction is initiated by nucleophilic attack
by the mostly 5dz2 orbital of complex 1 on the LUMO of acetyl
chloride (Fig. 8), and this leads easily to formation of the tetrahedral
intermediate F. There is a barrier to the pseudorotation to give the
intermediate I, which arises through steric effects when the tertiary
alkyl group is in the equatorial plane, but I can easily rearrange to
give the stable complex 9b (Figs. 8 and 9). It should be noted that I is
chiral at both carbon and platinum, and the diastereomer which is
calculated to be more stable is shown in Fig. 8. The gas phase
calculation predicts a very high barrier to formation of the ionic 5-
coordinate intermediates G and H, but this is misleading because
the ions will be stabilized in solution by solvation and probably by
reversible solvent coordination [35]. Intermediate G appears to be
a necessary intermediate in forming 9a, and G and H are calculated
to have similar energies, so there is a second viable route to 9b
through the intermediates G and H. Complex 9b is calculated to be
9 kJ molꢀ1 more stable than 9a, which is consistent with the
observed 3:1 ratio of these isomers at equilibrium. Overall, the
calculations support the formation of an initial tetrahedral inter-
mediate F, and show that it is possible for it to rearrange to 9b, but
a more detailed study will be needed to determine if this is
preferred to the more familiar ionic mechanism.
200
0
I
1 + MeCOCl
F
F
9b
9a
-200
Fig. 9. DFT calculated energies, with respect to complex 1 þ acetyl chloride, in the gas
phase for the intermediates and products of the reactions of Scheme 5.
organoplatinum(IV) derivatives 10e12. The products were formed
selectively by trans oxidative addition, as could easily be shown by
the 1H NMR spectra. For example, complex 10 gave only one
2
methylplatinum resonance at
a single resonance for the CH2Pt protons at
d
¼ 1.53, JPtH ¼ 70 Hz, and also
d
¼ 2.01, 2JPtH ¼ 95 Hz.
The structures of complexes 10 and 11 were determined and are
shown in Figs. 10 and 11. In complexes of this type, there can be
competition between potential hydrogen bond acceptor groups
[8,24,25,61,62,63]. In this case, the potential hydrogen bond
acceptors are the carbonyl group of the carboxylic acid, the bromide
ligand, or one of the oxygen atoms of the ethoxycarbonyl groups.
In both 10 and 11 the hydrogen bonding occurs between the
carboxylic acid groups of neighboring molecules, to give the classic
carboxylic acid dimer structures [10, O(5)/O(6A) 2.65(1); 11,
O(5)/O(6A) 2.64(1) Å]. The ester groups adopt the endo,exo or
exo,exo conformation in 10 or 11, respectively, and may be involved
2.4. Derivatives with hydrogen bonding groups
The bromomethyl derivatives of carboxylic acids shown in
Scheme 6 reacted with complex 1 to give the corresponding
in
bonding.
Platinum(IV) complexes containing amide or alcohol functional
p-stacking interactions, but they are not involved in hydrogen
groups were prepared according to Scheme 7. They were formed
selectively as the products of trans oxidative addition, as shown by
the 1H NMR spectra. For example, complex 14 gave only one
methylplatinum resonance at
d
¼ 1.56, 2JPtH ¼ 69 Hz, and one CH2Pt
2
resonance at
methylplatinum resonance at
d
¼ 2.10, JPtH ¼ 92 Hz and complex 15 gave one
d
¼ 1.57, 2JPtH ¼ 71 Hz, and one PtCH2
2
resonance at
d
¼ 2.88, JPtH ¼ 91 Hz.
Fig. 8. Calculated structures of reagents, intermediates and products, and frontier
orbitals for 1 and MeCOCl.
Scheme 6. Platinum(IV) complexes with carboxylic acid groups.

M. Safa, R.J. Puddephatt / Journal of Organometallic Chemistry 724 (2013) 7e16
13
Scheme 7. Platinum(IV) complexes with amide or alcohol functional groups.
3. Conclusions
For the complexes [PtMe2(NN)], where NN ¼ bebipy or bipy,
both the HOMO and LUMO are calculated to be lower in energy for
bepipy [HOMO, mostly platinum 5dz2, ꢀ4.486 and ꢀ4.978 eV;
LUMO, mostly ligand 2pp*, ꢀ3.407 and ꢀ4.027 eV, for NN ¼ bipy
and bebipy respectively], and the HOMOeLUMO gap is also smaller
Fig. 10. The structure of complex 10, showing the dimer formed by hydrogen bonding.
Selected bond parameters: Pt(1)eN(1) 2.155(6); Pt(1)eN(2) 2.166(6); Pt(1)eC(17)
2.085(7); Pt(1)eC(18) 2.124(6); Pt(1)eC(19) 2.099(7); Pt(1)eBr(1) 2.533(8); O(5)/
O(6A) 2.65(1) Å.
The structure of complex 13 was determined and is shown in
Fig. 12, and confirms that it is the product of trans oxidative addi-
tion to complex 1. The complex forms a supramolecular polymer by
forming intermolecular NH/BrPt hydrogen bonds. The hydrogen
bond distance N(3)/Br(1) ¼ 3.51 Å is in the accepted range of
3.12e3.69 Å for such hydrogen bonds [64], and the PtBr group is
evidently preferred over the amide or ester carbonyl groups as
hydrogen bond acceptor [65,66,67,68,69,70]. The ester groups
adopt the endo,endo conformation and they are not involved in the
hydrogen bonding.
Fig. 11. The structure of complex 11, showing the dimer formed by hydrogen bonding.
Selected bond parameters: Pt(1)eN(1) 2.160(4); Pt(1)eN(2) 2.162(4); Pt(1)eC(17)
2.048(6); Pt(1)eC(18) 2.063(5); Pt(1)eC(19) 2.103(5); Pt(1)eBr(1) 2.5955(6); O(5)/
O(6A) 2.64(1) Å.
Fig. 12. The structure of complex 13, showing the supramolecular polymer formed by
hydrogen bonding. Selected bond parameters: Pt(1)eN(1) 2.154(5); Pt(1)eN(2)
2.163(5); Pt(1)eC(1) 2.067(7); Pt(1)eC(2) 2.074(6); Pt(1)eC(19) 2.103(7); Pt(1)eBr(1)
2.545(1); Br(1)/N(3A) 3.51(1) Å.

14
M. Safa, R.J. Puddephatt / Journal of Organometallic Chemistry 724 (2013) 7e16
for bebipy [1.079 and 0.951 eV for bipy and bepipy respectively].
These differences reflect the electronic properties of the ethox-
ycarbonyl substituents in bebipy, and lead to it being a weaker
donor ligand than bipy. The weaker ligating ability of bebipy is most
clearly seen in the instability of the hydrogen peroxide adduct
[Pt(OH)2Me2(bebipy)] towards dissociation of the bebipy ligand,
whereas the corresponding bipy complex is thermally stable
tube. The color of the solution changed from purple to yellow, and
the product was isolated by evaporation of the solvent and
recrystallization from CH2Cl2/pentane. NMR in CD2Cl2:
d
(1H) ¼ 1.48
(t, 6H, 3JHH ¼ 7 Hz, CH3C), 4.53 (q, 4H, 3JHH ¼ 7 Hz, CH2C), 8.17 (d, 2H,
3
3JHH ¼ 5 Hz, H5), 8.66 (s, 2H, H3), 9.97 (d, 2H, JHH ¼ 5 Hz,
3JPtH ¼ 48 Hz, H6). Anal. Calcd. for C16H16Cl2N2O4Pt: C, 33.94; H,
2.85; N, 4.95. Found: C, 33.54; H, 2.63; N, 4.68%.
[37,39]. The p-conjugation of the ester substituents of bebipy leads
the eCO2C groups to be roughly coplanar with the pyridyl groups,
but there seems little preference for any of the possible endo,endo,
endo,exo or exo,exo conformations of the ester groups, and all have
been observed in the solid state structures of the platinum
complexes, with the preferred conformation probably determined
4.1.3. [PtBr2Me2(bebipy)], 4
Excess bromine (0.01 mL) was added slowly to a solution of
complex 1 (0.030 g, 0.057 mmol) in dry CH2Cl2 (5 mL). The color of
the solution rapidly changed from purple to orange. After 30 min,
the volume of solvent was reduced and pentane (2 mL) was added
to precipitate the product as an orange powder, which was sepa-
rated, washed with pentane (3 ꢂ 2 mL) and ether (3 ꢂ 2 mL) and
then dried under high vacuum. Yield 80%. NMR in CD2Cl2:
by
p-stacking or other intermolecular packing forces.
The complex [PtMe2(bebipy)] takes part in a wide range of
oxidative addition reactions to give functional organoplatinum(IV)
complexes, some of which contain hydrogen bonding functionality
(carboxylic acids, amides or alcohol). These complexes can form
supramolecular dimers or, in one case, a polymer through inter-
molecular hydrogen bonding.
3
2
d
(1H) ¼ 1.48 (t, 6H, JHH ¼ 7 Hz, CH3C), 2.07 (s, 6H, JPtH ¼ 71 Hz,
PtCH3), 4.54 (q, 4H, 3JHH ¼ 7 Hz, CH2C), 8.29 (d, 2H, 3JHH ¼ 5 Hz, H5),
8.97 (s, 2H, H3), 9.07 (d, 2H, JHH ¼ 5 Hz, JPtH ¼ 18 Hz, H6). Anal.
Calcd. for C18H22Br2N2O4Pt: C, 31.55; H, 3.24; N, 4.09. Found: C,
31.37; H, 3.13; N, 3.88%.
3
3
4. Experimental
4.1.4. [PtI2Me2(bebipy)], 5
All reactions were carried out under nitrogen using standard
Schlenk techniques, unless otherwise specified. NMR spectra were
recorded by using a Varian Mercury 400, or Varian Inova 400 or 600
To a solution of complex 1 (0.035 g, 0.066 mmol) in dry CH2Cl2
(15 mL) was added excess iodine (0.033 g, 0.129 mmol). The color
changed from purple to dark red. After 5 min, the solvent was
evaporated to give the product as a red powder, which was
recrystallized from CH2Cl2/pentane. Yield: 83%. NMR in CD2Cl2:
spectrometer. The ligand bebipy and complex [Pt2Me4(m-SMe2)2]
were prepared according to the literature [26,71]. DFT calculations
were carried out by using the Amsterdam Density Functional
program based on the BLYP functional, with double-zeta basis set
and first-order scalar relativistic corrections [72,73]. The reported
results are from gas phase calculations .The energy minima were
confirmed by vibrational frequency analysis in each case.
3
2
d
(1H) ¼ 1.49 (t, 6H, JHH ¼ 7 Hz, CH3C), 2.42 (s, 6H, JPtH ¼ 73 Hz,
PtCH3), 4.55 (q, 4H, 3JHH ¼ 7 Hz, CH2C), 8.30 (d, 2H, 3JHH ¼ 5 Hz, H5),
3
3
9.02 (s, 2H, H3), 9.07 (d, 2H, JHH ¼ 5 Hz, JPtH ¼ 21 Hz, H6). Anal.
Calcd. for C18H22I2N2O4Pt: C, 27.74; H: 2.85; N, 3.59. Found: C,
28.08; H, 2.86; N, 3.59%. Crystals of 5.1.5I2 were grown directly by
slow diffusion of pentane into a similar reaction mixture.
4.1. X-ray structure determinations
4.1.5. [Pt(OH)2Me2(bebipy)], 6
A crystal was mounted on a glass fiber and data were collected at
150(2) K by using a Nonius Kappa-CCD or Bruker Smart Apex II CCD
diffractometer. The unit cell parameters were calculated and refined
from the full data set, and the structures were solved and refined by
using the SHELX software [74,75]. Details of the crystal data and
refinement parameters, and bond distances and angles, for all
complexes are given in the CIF files. In complex 2, there was disorder
of the methyl/chloro ligands in both independent molecules, so
bond parameters for these groups are not precise, and there was
a molecule of CH2Cl2 of crystallization. In complexes 4 and 5, one of
the ethoxy groups was disordered over two positions and was
modeled with isotropic carbon atoms in each case. Complex 11
crystallized with a molecule of acetone of crystallization.
To a solution of complex 1 (0.030 g, 0.057 mmol) in acetone was
added excess H2O2 (0.01 mL). The color changed from purple to
colorless. After 30 min, the solvent was evaporated to give the
product as a white solid, which was washed with pentane
(2 ꢂ 3 mL) and ether (2 ꢂ 3 mL) and dried under high vacuum.
Yield: 80%. NMR in CD2Cl2:
d
(1H) ¼ 1.47 (t, 6H, 3JHH ¼ 7 Hz, CH3C),
2
3
1.66 (s, 6H, JPtH ¼ 70 Hz, PtCH3), 4.52 (q, 4H, JHH ¼ 7 Hz, CH2C),
8.21 (d, 2H, 3JHH ¼ 5 Hz, H5), 8.91 (s, 2H, H3), 9.01 (d, 2H, 3JHH ¼ 5 Hz,
3JPtH ¼ 18 Hz, H6). Anal. Calcd. for C18H24N2O6Pt.2H2O: C, 36.30; H,
4.74; N, 4.70. Found: C, 36.37; H, 4.30; N, 4.82%.
4.1.6. [PtIMe3(bebipy)], 7
Excess iodomethane (0.025 mL) was added to a solution of
complex 1 (0.050 g, 0.095 mmol) in acetone (10 mL). The color of the
solution changed from purple to yellow. The solution was cooled to
4.1.1. [PtMe2(bebipy)], 1
To a solution of 4,40-diethoxycarbonyl-2-20-bipyridine (0.52 g,
0
ꢁC overnight, to precipitate the product as a pale yellow solid,
1.73 mmol) in ether (20 mL) was added [Pt2Me4(
m
-SMe2)2] (0.50 g,
which was separated, washed with pentane (3 ꢂ 2 mL) and dried
0.87 mmol). The color of the solution quickly turned to purple, and
the product precipitated as a purple solid. After 40 min, the product
was separated, washed with pentane (3 ꢂ 3 mL) and then dried
under high vacuum. Yield: 84%. NMR in acetone-d6:
d
(1H) ¼ 0.60 (s,
3H, 2JPtH ¼ 72 Hz, PtMe trans to I), 1.45 (t, 6H, 3JHH ¼ 7 Hz, CH3C),1.52
(s, 6H, 2JPtH ¼ 71 Hz, PtMe trans to N), 4.53 (q, 4H, 3JHH ¼ 7 Hz, CH2C),
8.33 (d, 2H, 3JHH ¼ 6 Hz, H5), 9.20 (s, 2H, H3), 9.25 (d, 2H, 3JHH ¼ 6 Hz,
3JPtH ¼ 20 Hz, H6). Anal. Calcd. for C19H25IN2O4Pt: C, 34.19; H, 3.78;
N, 4.20. Found: C, 34.30; H, 3.89; N, 4.16%.
under high vacuum. Yield: 91%. NMR in acetone-d6:
d
(1H) ¼ 1.14 (s,
6H, 2JPtH ¼ 86 Hz, PtCH3), 1.45 (t, 6H, 3JHH ¼ 7 Hz, CH3C), 4.49 (q, 4H,
3JHH ¼ 7 Hz, CH2C), 8.14 (d, 2H, 3JHH ¼ 6 Hz, H5), 8.79 (s, 2H, H3), 9.42
(d, 2H, 3JHH ¼ 6 Hz, 3JPtH ¼ 28 Hz, H6). Anal. Calcd. for C18H22N2O4Pt:
C, 41.14; H, 4.22; N, 5.33. Found: C, 40.85; H, 4.04; N, 5.45%.
4.1.7. [PtClMe2(CO2Et)(bebipy)], 8
This was synthesized in a similar way from complex 1 (0.035 g,
0.066 mmol) in dry CH2Cl2 (15 mL) and ethyl chloroformate
4.1.2. [PtCl2(bebipy)], 3
Excess hydrochloric acid (0.0035 mL, 3 M) was added to a solu-
tion of complex 1 (0.0034 g, 0.006 mmol) in CH2Cl2 (1 g) in an NMR
(0.007 mL). Yield: 79%. NMR in CD2Cl2:
d
(1H) ¼ 0.85 (t, 3H,
3
3JHH ¼ 7 Hz, CH3C), 1.48 (t, 6H, JHH ¼ 7 Hz, CH3C), 1.65 (s, 6H,

M. Safa, R.J. Puddephatt / Journal of Organometallic Chemistry 724 (2013) 7e16
15
3
3
2JPtH ¼ 71 Hz, PtCH3), 3.77 (q, 2H, 3JHH ¼ 7 Hz, 4JPtH ¼ 5 Hz, CH2C),
4.54 (q, 4H, 3JHH ¼ 7 Hz, CH2C), 8.27 (d, 2H, 3JHH ¼ 5 Hz, H5), 8.93 (s,
2H, H3), 9.13 (d, 2H, 3JHH ¼ 5 Hz, 3JPtH ¼ 17 Hz, H6). Anal. Calcd. for
C21H27ClN2O6Pt: C, 39.78; H, 4.29; N, 4.42. Found: C, 39.79; H, 4.52;
N, 4.37%.
CH2C), 8.31 (d, 2H, JHH ¼ 6 Hz, H5), 9.09 (d, 2H, JHH ¼ 6 Hz,
3JPtH ¼ 19 Hz, H6), 9.13 (s, 2H, H3). Anal. Calcd. for C20H25BrN2O6Pt:
C, 36.16; H, 3.79; N, 4.22. Found: C, 35.71; H, 3.66; N, 4.08%.
4.1.10. [PtBrMe2(CH2-4-C6H4-CO2H)(bebipy)], 11
This was prepared similarly from complex
1 (0.050 g,
4.1.8. [PtClMe2(COMe)(bebipy)], 9
0.095 mmol) and BrCH2-4-C6H4-CO2H (0.021 g, 0.095 mmol). Yield:
To a stirred solution of complex 1 (0.038 g, 0.063 mmol) in dry
CH2Cl2 (15 mL) was added acetyl chloride (0.004 g, 0.063 mmol).
The color of the solution turned to yellow within 5 min. After 1 h,
the solvent was removed and the product was washed pentane
86%. NMR in acetone-d6:
d
(1H) ¼ 1.44 (t, 6H, 3JHH ¼ 7 Hz, CH3C), 1.54
(s, 6H, 2JPtH ¼ 72 Hz, PtCH3), 2.87 (s, 2H, 2JPtH ¼ 95 Hz, PtCH2), 4.49
3
3
3
(q, 4H, JHH ¼ 7 Hz, CH2C), 6.46 (d, 2H, JHH ¼ 8 Hz, JPtH ¼ 18 Hz,
Ho), 7.27 (d, 2H, 3JHH ¼ 8 Hz, Hm), 8.17 (d, 2H, 3JHH ¼ 7 Hz, H5), 8.93
(s, 2H, H3), 8.97 (d, 2H, 3JHH ¼ 7 Hz, 3JPtH ¼ 19 Hz, H6). Anal. Calcd.
for C26H29BrN2O6Pt: C, 42.17; H, 3.95; N, 3.78. Found: C, 41.73; H,
4.06; N, 3.44%. Single crystals of the acetone solvate were grown
from acetone/pentane.
(3 ꢂ 3 mL) and ether (3 ꢂ 3 mL) and then dried under high vacuum.
2
Yield: 84%. NMR in CD2Cl2: 9b,
d
(1H) ¼ 0.75 (s, 3H, JPtH ¼ 74 Hz,
3
PtMe trans to Cl), 1.47 (t, 6H, JHH ¼ 7 Hz, CH3C), 1.57 (s, 3H,
2JPtH ¼ 72 Hz, PtMe trans to N), 2.58 (s, 3H, 3JPtH ¼ 10 Hz, CH3C), 4.53
(q, 4H, 3JHH ¼ 7 Hz, CH2C), 8.22 (d, 1H, 3JHH ¼ 5 Hz, H3), 8.23 (d, 1H,
3JHH ¼ 5 Hz, H5), 8.90 (s, 2H, H3), 8.97 (d, 1H, JHH ¼ 5 Hz,
4.1.11. [PtBrMe2(CH2-4-C6H4-CH2CO2H)(bebipy)], 12
This was prepared in a similar way from complex 1 (0.050 g,
0.095 mmol) and BrCH2-4-C6H4-CH2CO2H (0.022 g, 0.095 mmol).
3
3
3
3JPtH ¼ 20 Hz, H6), 9.33 (d, 1H, JHH ¼ 5 Hz, JPtH ¼ 19 Hz, H6); 9a,
3
2
d
(1H) ¼ 1.48 (t, 3H, JHH ¼ 7 Hz, CH3C), 1.59 (s, 6H, JPtH ¼ 72 Hz,
3
3
3
PtCH3), 2.00 (s, 3H, JPtH ¼ 14 Hz, CH3C), 4.54 (q, 4H, JHH ¼ 7 Hz,
Yield: 88%. NMR in acetone-d6:
d
(1H) ¼ 1.44 (t, 6H, JHH ¼ 7 Hz,
3
2
CH2C), 8.27 (d, 2H, JHH ¼ 5 Hz, H5), 8.97 (s, 2H, H3), 9.13 (d, 2H,
CH3C), 1.50 (s, 6H, 2JPtH ¼ 70 Hz, PtCH3), 2.77 (s, 2H, JPtH ¼ 90 Hz,
PtCH2), 3.21 (s, 2H, CH2CO), 4.50 (q, 4H, 3JHH ¼ 7 Hz, CH2C), 6.27 (d,
2H, 3JHH ¼ 8 Hz, 3JPtH ¼ 18 Hz, Ho), 6.51 (d, 2H, 3JHH ¼ 8 Hz, Hm), 8.15
3JHH ¼ 5 Hz, JPtH ¼ 20 Hz, H6). Anal. Calcd. for C20H25ClN2O5Pt: C,
3
39.77; H, 4.17; N, 4.64. Found: C, 39.51; H, 4.40; N, 4.55%.
3
3
(d, 2H, JHH ¼ 6 Hz, H5), 8.86 (s, 2H, H3), 8.95 (d, 2H, JHH ¼ 6 Hz,
3JPtH ¼ 19 Hz, H6). Anal. Calcd. for C27H31BrN2O6Pt: C, 42.98; H, 4.14;
N, 3.71. Found: C, 42.75; H, 3.99; N, 3.65%.
4.1.9. [PtBrMe2(CH2CO2H)(bebipy)], 10
To a solution of complex 1 (0.050 g, 0.095 mmol) in acetone
(15 mL) was added BrCH2CO2H (0.013 g, 0.095 mmol). After 3 h, the
solvent was evaporated under vacuum, and the yellow solid
product was washed with water (3 ꢂ 3 mL) and pentane (3 ꢂ 3 mL),
and dried under high vacuum. Yield: 88%. NMR in acetone-d6:
4.1.12. [PtBrMe2(CH2CONHC6H5)(bebipy)], 13
This was prepared similarly from complex
1 (0.050 g,
0.095 mmol) and BrCH2CONHPh (0.021 g, 0.095 mmol). Yield 85%.
3
2
d
(1H) ¼ 1.46 (t, 6H, JHH ¼ 7 Hz, CH3C), 1.53 (s, 6H, JPtH ¼ 70 Hz,
NMR in CD2Cl2:
d
(1H) ¼ 1.45 (t, 6H, 3JHH ¼ 7 Hz, CH3C), 1.56 (s, 6H,
2
3
PtCH3), 2.01 (s, 2H, JPtH ¼ 95 Hz, PtCH2), 4.53 (q, 4H, JHH ¼ 7 Hz,
2JPtH ¼ 69 Hz, PtCH3), 2.12 (s, 2H, 2JPtH ¼ 92 Hz, PtCH2), 4.47 (q, 4H,
Table 1
Crystal and refinement data for the complexes.
Complex
Formula
fw
Cryst. syst.
Sp.gp.
a/Å
1
2.0.5CH2Cl2
C17.5H20Cl2N2O4Pt
588.34
Triclinic
P-1
9.7977(5)
13.4431(10)
14.7147(10)
95.261(3)
93.083(4)
90.059(4)
1927.1(2)
4
3
4
5.1.5I2
C18H22N2O4Pt
525.47
Monoclinic
P 21/c
8.1368(3)
31.7979(10)
13.7885(5)
90
92.392(2)
90
3564.4(2)
8
C16H16Cl2N2O4Pt
566.30
Triclinic
P-1
9.1862(10)
14.743(2)
15.111(2)
61.463(4)
84.528(6)
85.249(7)
1788.1(4)
4
C18H22Br2N2O4Pt
685.29
Monoclinic
P 21/n
12.0683(13)
6.4596(7)
26.273(3)
90
95.308(5)
90
2039.4(4)
4
C18H22I5N2O4Pt
1159.97
Triclinic
P-1
6.9682(3)
11.7601(7)
17.1027(8)
97.245(3)
93.582(3)
96.167(3)
1378.16(12)
2
b/Å
c/Å
ꢁ
ꢁ
a
b
g
/
/
ꢁ
/
V/Å3
Z
dc/Mg mꢀ3
1.958
7.898
0.096
2.028
7.584
0.061
2.104
8.170
0.063
2.232
10.825
0.068
2.795
10.716
0.035
m
/mmꢀ1
R1 (I > 2
sI)
wR2 (all data)
0.243
0.171
0.199
0.198
0.091
Complex
Formula
fw
Cryst. syst.
Sp.gp.
a/Å
9b
10
11
12
C
20H25ClN2O5Pt
C20H25BrN2O6Pt
664.42
Monoclinic
C2/c
23.1244(14)
6.8372(4)
30.2233(19)
90
92.465(2)
90
C29H35BrN2O7Pt
798.59
Monoclinic
P 21/n
7.4337(3)
33.1080(14)
12.0101(5)
90
94.137(2)
90
C26H30BrN3O5Pt
739.51
Monoclinic
P 21/c
7.2694(15)
16.904(3)
22.105(4)
90
96.66(3)
90
2697.9(9)
4
603.96
Monoclinic
P 21/c
9.8457(3)
12.2735(4)
18.0778(5)
90
100.873(2)
90
2145.33(11)
4
b/Å
c/Å
ꢁ
ꢁ
a
b
g
/
/
ꢁ
/
V/Å3
4774.1(5)
8
1.849
2948.2(2)
4
1.799
Z
dc/Mg mꢀ3
1.870
6.698
1.821
6.722
m
/mmꢀ1
7.588
6.163
R1 (I > 2
sI)
0.045
0.056
0.037
0.052
wR2 (all data)
0.122
0.107
0.071
0.164

16
M. Safa, R.J. Puddephatt / Journal of Organometallic Chemistry 724 (2013) 7e16
3
3JHH ¼ 7 Hz, CH2C), 6.65 (s, 1H, NH), 6.82 (d, 2H, JHH ¼ 8 Hz, Ho),
[19] B.A. McKeown, H.E. Gonzalez, M.R. Friedfeld, T.B. Gunnoe, T.R. Cundari,
M. Sabat, J. Am. Chem. Soc. 133 (2011) 19131.
6.88 (t, 1H, 3JHH ¼ 8 Hz, Hp), 7.02 (t, 2H, 3JHH ¼ 8 Hz, Hm), 7.98 (d, 2H,
[20] G. Mazzone, N. Russo, E. Sicilia, Inorg. Chem. 50 (2011) 10091.
[21] P.K. Monaghan, R.J. Puddephatt, J. Chem. Soc. Dalton Trans. (1988) 595.
[22] G.S. Hill, G.P.A. Yap, R.J. Puddephatt, Organometallics 18 (1999) 1408.
[23] S.M. Nabavizadeh, S. Habibzadeh, M. Rashidi, R.J. Puddephatt, Organometallics
29 (2010) 6359.
3JHH ¼ 6 Hz, H5), 8.75 (s, 2H, H3), 8.91 (d, 2H, JHH ¼ 6 Hz,
3
3JPtH ¼ 19 Hz, H6). Anal. Calcd. for C26H30BrN3O5Pt: C, 42.23; H, 4.09;
N, 5.68. Found: C, 42.27; H, 3.99; N, 5.33%.
[24] S. Achar, J.D. Scott, J.J. Vittal, R.J. Puddephatt, Organometallics 12 (1993) 4592.
[25] R.H.W. Au, M.C. Jennings, R.J. Puddephatt, Organometallics 28 (2009) 5052.
[26] G. Sprintschnik, H.W. Sprintschnik, P.P. Kirsch, D.G. Whitten, J. Am. Chem. Soc.
99 (1977) 4947.
[27] V. Shklover, M.-K. Nazeeruddin, S.M. Zakeeruddin, C. Barbe, A. Kay, T. Haibach,
W. Steurer, R. Hermann, H.-U. Nissen, M. Gratzel, Chem. Mater. 9 (1997) 430.
[28] D. Hanss, J.C. Freys, G. Bernardinelli, O.S. Wenger, Eur. J. Inorg. Chem. (2009)
4850.
[29] C.L. Linfoot, P. Richardson, T.E. Hewat, O. Moudam, M.M. Forde, A. Collins,
F. White, N. Robertson, Dalton Trans. 39 (2010) 8945.
[30] A. Gunyar, D. Betz, M. Drees, E. Herdtweck, F.E. Kuhn, J. Mol. Catal. A 331
(2010) 117.
4.1.13. [PtBrMe2(CH2CONH-4-C6H4-t-Bu)(bebipy)], 14
This was prepared similarly from complex
0.095 mmol) and BrCH2CONH-4-C6H4-t-Bu (0.022 g, 0.095 mmol).
1 (0.050 g,
Yield: 87%. NMR in CD2Cl2:
d
(1H) ¼ 1.24 (s, 9H, t-Bu), 1.45 (t, 6H,
2
3JHH ¼ 7 Hz, CH3C), 1.56 (s, 6H, JPtH ¼ 69 Hz, PtCH3), 2.10 (s, 2H,
2JPtH ¼ 92 Hz, PtCH2), 4.49 (q, 4H, JHH ¼ 7 Hz, CH2C), 6.62 (s, 1H,
3
NH), 6.74 (d, 2H, 3JHH ¼ 9 Hz, Ho), 7.06 (d, 2H, 3JHH ¼ 9 Hz, Hm), 7.99
3
3
(d, 2H, JHH ¼ 6 Hz, H5), 8.80 (s, 2H, H3), 8.92 (d, 2H, JHH ¼ 6 Hz,
3JPtH ¼ 19 Hz, H6). Anal. Calcd. for C30H38BrN3O5Pt: C, 45.29; H, 4.81;
N, 5.28. Found: C, 44.93; H, 4.89; N, 5.19%.
[31] S. Achar, V.J. Catalano, Polyhedron 16 (1997) 1555.
[32] Y. Nishiuchi, A. Takatama, T. Suzuki, K. Shinozaki, Eur. J. Inorg. Chem. (2011)
1815.
[33] G. Janjic, J. Andric, A. Kapor, Z.D. Bugarcic, S.D. Zaric, Cryst. Eng. Commun. 12
(2010) 3773.
4.1.14. [PtBrMe2(CH2-3-C6H4-CH2OH)(bebipy)], 15
This was prepared similarly from complex
0.095 mmol) and BrCH2-3-C6H4-CH2OH (0.019 g, 0.095 mmol).
1 (0.050 g,
[34] A.J. Canty, M.G. Gardiner, R.C. Jones, M. Sharma, Aust. J. Chem. 64 (2011) 1355.
[35] S.M. Nabavizadeh, H. Amini, M. Rashidi, K.R. Pellarin, M.S. McCready,
B.F.T. Cooper, R.J. Puddephatt, J. Organomet. Chem. 713 (2012) 60.
[36] N. Margiotta, R. Ranaldo, F.P. Intini, G. Natile, Dalton Trans. 40 (2011) 12877.
[37] K. Thorshaug, I. Fjeldahl, C. Romming, M. Tilset, J. Chem. Soc. Dalton Trans.
(2003) 4051.
[38] M. Safa, M.C. Jennings, R.J. Puddephatt, Organometallics 31 (2012) 3539.
[39] V.V. Rostovtsev, L.M. Henling, J.A. Labinger, J.E. Bercaw, Inorg. Chem. 41 (2002)
3608.
[40] R.A. Gossage, A.D. Ryabov, A.L. Spek, D.J. Stufkens, J.A.M. van Beek, R. van Eldik,
G. van Koten, J. Am. Chem. Soc. 121 (1999) 2488.
[41] J.A.M. van Beek, G. van Koten, W.J.J. Smeets, A.L. Spek, J. Am. Chem. Soc. 108
(1986) 5010.
Yield: 84%. NMR acetone-d6:
d
(1H) ¼ 1.45 (t, 6H, 3JHH ¼ 7 Hz, CH3C),
1.57 (s, 6H, 2JPtH ¼ 71 Hz, PtCH3), 2.88 (s, 2H, 2JPtH ¼ 91 Hz, PtCH2),
3
4.03 (s, 2H, CH2O), 4.51 (q, 4H, JHH ¼ 7 Hz, CH2C), 6.12 (d, 1H,
3JHH ¼ 8 Hz, 3JPtH ¼ 18 Hz, Ho), 6.47 (t, 1H, 3JHH ¼ 8 Hz, Hm), 6.68 (t,
3
3
1H, JHH ¼ 8 Hz, Hp), 6.78 (d, 1H, JHH ¼ 8 Hz, Hm’), 8.19 (d, 2H,
3JHH ¼ 6 Hz, H5), 8.81 (s, 2H, H3), 9.10 (d, 2H, JHH ¼ 6 Hz,
3
3JPtH ¼ 19 Hz, H6). Anal. Calcd. for C26H31BrN2O5Pt: C, 42.98; H, 4.30;
N, 3.86. Found: C, 42.81; H, 4.26; N, 3.79% (Table 1).
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Acknowledgments
We thank the NSERC (Canada) and Shiraz University for financial
support.
Appendix A. Supplementary material
CCDC 902716-902724; contains the supplementary crystallo-
graphic data for this paper. These data can be obtained free of
charge from The Cambridge Crystallographic Data Centre via www.
ccdc.cam.ac.uk/data_request/cif.
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