Intramolecularly stabilised group 10 metal stannyl and stannylene complexes: Multi-pathway synthesis and observation of platinum-to-tin alkyl transfer

DOI: 10.1002/chem.201404071

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&

Stannylene Complexes

Intramolecularly Stabilised Group 10 Metal Stannyl and

Stannylene Complexes: Multi-pathway Synthesis and Observation

of Platinum-to-Tin Alkyl Transfer

Stefan Warsink,^[a]Eric J. Derrah,^[a]Cornelis A. Boon,^[a]Yves Cabon,^[a]Jeroen J. M. de Pater,^[b]

Martin Lutz,^[c]Robertus J. M. Klein Gebbink,^[a]and Berth-Jan Deelman*^{[a, b]}

Abstract: Reaction of [PdClMe(P^N)₂] with SnCl₂followed by

Cl-abstraction leads to apparent PdꢀC bond activation, re-

tive addition of RSnCl₃(R=Me, Bu, Ph) to M⁰precursors

(M=Pd or Pt) in the presence of P^N ligands results in di-

sulting

in

methylstannylene

species

trans-

phosphinostannylene

pincer

complexes

trans-

[PdCl{(P^N)₂SnClMe}][BF₄] (P^N=diaryl phosphino-N-hetero-

cycle). In contrast, reaction of Pt analogues with SnCl₂leads

to PtꢀCl bond activation, resulting in methylplatinum spe-

cies trans-[PtMe{(P^N)₂SnCl₂}][BF₄]. Over time, they isomerise

to methylstannylene species, indicating that both kinetic

and thermodynamic products can be isolated for Pt, whereas

for Pd only methylstannylene complexes are isolated. Oxida-

[MCl{(P^N)₂SnCl(R)}][SnCl₄R], which are structurally similar to

the products from SnCl₂insertion. This showed that addition

of RSnCl₃to M⁰results in formal SnꢀCl bond oxidative add-

ition. A probable pathway of activation of the tin reagents

and formation of different products is proposed and the

relevancy of the findings for Pd and Pt catalysed processes

that use SnCl₂as a co-catalyst is discussed.

Introduction

nylene moiety buttressed by two 2-diphenylphosphinopyridine

ligands (PyPPh₂; a) [Eq. (1)].^[26,27]We speculated that related

transition-metal dichlorostannylene complexes [MR(L₂)SnCl₂]Cl

or [MR(L₂)SnCl₂][SnCl₃] (L=ligand), due to the (observed)

strong trans influence of the SnCl₂moiety, may play a role in

Group 10 metal catalysed transformations that involve SnCl₂as

a co-catalyst.^[26]

Tin dichloride can be applied as a reagent in the palladium-

catalysed hydrostannylation for the selective formation of

monoalkyl tin trichlorides.^[1]It is also an important co-catalyst

for many Group 10 metal-catalysed reactions, such as hydrofor-

mylation,^[2–8]1,5-cyclooctadiene isomerization,^[9]cycliza-

tion,^[10–14]allylation,^[15,16]and alkoxycarbonylation of al-

kenes.^[17–21]Although the exact role of SnCl₂as a co-catalyst is

not completely understood, it is believed that it inserts into

the MꢀCl bond (M=Group 10 metal), forming trichlorostannyl

In the case of Pt, these rather unique diphosphinostannylene

complexes are obtained by reaction of SnCl₂with 1) trans-

[PtClMe(PyPPh₂)₂] in the presence of Ag[BF₄] [Eq. (1)] or

2) [PtClMe(COD)] in the presence of PyPPh₂and [NnBu₄][BF₄]

[Eq. (2)]. These reactions can be considered as formal substitu-

tion of the chloride anion on the transition metal centre by

SnCl₂.^[26]

ꢀ

species [MꢀSnCl₃] where SnCl₃serves as a weakly coordinat-

ing anion and/or as a trans-labilising ligand.^[8,22–25]

Recently, we reported on the formation of Group 10 diphos-

phinostannylene complexes consisting of a central SnCl₂stan-

[a] Dr. S. Warsink,⁺Dr. E. J. Derrah,⁺C. A. Boon, Dr. Y. Cabon,

Prof. Dr. R. J. M. Klein Gebbink, Prof. Dr. B.-J. Deelman

Organic Chemistry and Catalysis, Debye Institute for Nanomaterial Science

Faculty of Science, Utrecht University

Universiteitsweg 99, 3584 CG Utrecht (The Netherlands)

[b] Dr. J. J. M. d. . Pater, Prof. Dr. B.-J. Deelman

ARKEMA B.V. Location Vlissingen

P.O. Box 70, 4380 AB Vlissingen (The Netherlands)

E-mail: berth-jan.deelman@arkema.com

[c] Dr. M. Lutz

Crystal and Structural Chemistry, Bijvoet Center for Biomolecular Research

Faculty of Science, Utrecht University

Padualaan 8, 3584 CH Utrecht (The Netherlands)

[⁺] These authors share the first authorship.

Supporting information for this article is available on the WWW under

http://dx.doi.org/10.1002/chem.201404071.

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In contrast, the reaction for the palladium precursor

[PdClMe(COD)] was found to give an entirely different result in-

volving transfer of the methyl group to tin and resulting in or-

ganostannylene species 2a [Eq. (3)]. Reaction of RSnCl₃with

a Pd⁰precursor was shown to produce organostannylene com-

plexes 3a–5a through oxidative addition of the SnꢀCl bond

[Eq. (4)].^[27]

the findings for palladium- and platinum-catalysed processes

that use SnCl₂as a co-catalyst is discussed.

Results and Discussion

Preparation of P^N ligands bis-3-trifluoromethylphenyl-2-

pyridylphosphine b and 2-(bis-3-trifluoromethylphenylphos-

phino)-1-methylimidazole d

While 2-diphenylphosphinopyridine PyPPh₂(a) is commercially

available and 2-diphenylphosphino-N-methylimidazole ImPPh₂

(c) was obtained by a reported procedure,^[30]the novel trifluor-

omethyl-functionalised ligands PyP(3-CF₃Ph)₂(b) and ImP(3-

CF₃Ph)₂(d) were prepared as outlined in Scheme 1 using re-

ported procedures for CF₃PhMgBr,^[31](2-C₅H₄N)MgCl·LiCl,^[32]and

lithiated 1-methylimidazole.^[30]

It should be noted that complexes containing a direct

Group 10 metal to tin bond have attracted the interest of

other research groups, and several related complexes with dif-

ferent ligand systems and/or substituents on Sn have become

known.^[28,29]

Herein, several new P^N ligands that differ considerably

from a in their donating properties, notably fluorinated diaryl

phosphinopyridine PyP(3-CF₃Ph)₂(b), methylimidazole ligands

ImPPh₂(c), and ImP(3-CF₃Ph)₂(d) (Figure 1), are employed to

Scheme 1. Synthesis of (3-CF₃C₆H₄)₂PPy (b) and (3-CF₃C₆H₄)₂PIm (d). i) 1 equiv

Mg, THF, 368C; ii) 0.5 equiv Cl₂PNEt₂, THF, 108C; iii) excess PCl₃, 908C, 1 h;

iv) 1 equiv iPrMgCl·LiCl, 1.3 equiv 1,4-dioxane, THF, 58C; v) 58C; vi) 1 equiv

nBuLi, THF, ꢀ808C; vii) ꢀ758C.

Reaction of tin dichloride with [PdClMe(COD)] and

[PtClMe(COD)] in the presence of P^N ligands b–d and

tetrafluoroborate salts

Figure 1. Bifunctional P^N ligands used in this study.

Diphosphinostannylene–palladium

complexes

trans-

gauge the influence of the ligand properties on the observed

reactivity in substitution and oxidative addition reactions, as

well as on the structure of the resulting complexes. Further-

more, we have extended our studies to the activation of orga-

notin trichlorides by Pt⁰precursors. Also, structural data for

several of the essential compounds is presented and com-

pared. Finally, a comparison is made between the reactivity of

the palladium and platinum complexes and the relevancy of

[PdCl{(P^N)₂SnClMe}][BF₄] (2b and 2d) containing fluorinated

ligands b and d were prepared from [PdClMe(COD)] in good

yield by sequential addition of b or d, SnCl₂, and Ag[BF₄] in

THF [Eq. (5)]. The low solubility of the non-fluorinated methyl-

imidazolyl derivative trans-[PdCl{(c)₂SnClMe}][BF₄] (2c) preclud-

ed the use of this method for c, because the byproduct AgCl is

not easily removed from the insoluble product. Compound 2c

was therefore prepared by a one-pot method developed previ-

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ously for pyridyl derivative 2a [Eq. (6)] utilising [NnBu₄][BF₄]

(3 equiv) as an ion-exchange reagent. The same strategy was

insufficient for fluorinated derivatives 2b and 2d, as no chlor-

ide exchange occurred with [NnBu₄][BF₄] (according to ¹¹B{¹H}

and ¹⁹F{¹H} NMR spectroscopy).

a methylstannylene moiety. For the corresponding signal in

the ¹³C{¹H} NMR spectra (14.9 (2b) or 13.5 ppm (2d)), tin satel-

lites were not observed owing to the low intensity of the sig-

nals. However, this coupling information (¹J_CSn=430 Hz (2b),

¹J_CSn=550 Hz (2d)) could be extracted from the ¹H/¹³C{¹H}-

HSQC NMR spectrum (Figure 2).^[33]The chemical shift values

1

Figure 2. Partial H/¹³C{¹H}-HSQC contour plot of trans-[PdCl{(b)₂(SnClMe)}]

[BF₄] (2b) in CD₂Cl₂, showing the presence of tin satellite cross-signals from

which J_CSnwas determined. A signal of a toluene impurity is labelled with

an asterisk.

A single resonance in the ³¹P{¹H} NMR spectra of complex-

es 2b, c, and d, shifted downfield compared to that of the free

ligand, is consistent with phosphine coordination in a symmet-

rical trans-configuration (see Table 1 and the Experimental Sec-

tion for full spectroscopic data).

1

2

1

and J_HSnand J_CSncoupling constants found for the stannylene

moieties are comparable to those of 2a and trans-

[PdCl{(a)₂SnClMe}][SnCl₄Me] 3a,^[26,27]confirming their close

structural analogy.

The presence of two signals in the ¹⁹F{¹H} NMR spectra of

both 2b and 2d in a 3:1 ratio indicates successful chloride

substitution by [BF₄]^ꢀ, which is further corroborated by two

singlets at ꢀ1.1 ppm (2b) and 4.1 ppm (2d) in the ¹¹B{¹H} NMR

spectra. The stannylene moieties appear as a broad resonance

at 62.4 ppm (2b) and ꢀ159.4 ppm (2d), respectively in the

¹¹⁹Sn{¹H} NMR spectra. The limited solubility of 2c prevented

its analysis by ¹¹B, ¹³C, and ¹¹⁹Sn NMR spectroscopy.

Trifluoromethylated diphosphinostannylene platinum com-

plex [PtMe{(b)₂SnCl₂}][BF₄] (1b) was synthesised in an analo-

gous fashion as [PtMe{(a)₂SnCl₂}][BF₄] (1a)^[26]by reacting

[PtClMe(COD)] with ligand b and tin dichloride, followed by

chloride abstraction with Ag[BF₄]. Similarly to 1a, product 1b

bears its methyl group on platinum, as is evidenced by the

chemical shift of the methyl signal in the ¹H NMR spectrum

A singlet in the ¹H NMR spectra of 2b–d (1.36–1.44 ppm)

showing tin satellites with ²J_HSn=55–66 Hz is consistent with

Table 1. Relevant NMR data for Pd complexes 2a–d, 3a–d, 4a–d, and 5a in CD₂Cl₂.

2

1

2

1

d ¹H SnCH₃, SnCH₂J_HSnd H SnCH₃, SnCH₂J_HSn

of cation [ppm]

d

¹³C SnCH₃, SnCH₂J_CSn

d

¹³C SnCH₃, SnCH₂J_CSn

d

¹¹⁹Sn

d

¹¹⁹Sn

d

³¹P ²J_PSn

[ppm] [Hz]

[Hz] of anion

[ppm]

[Hz] of cation

[ppm]

[Hz] of anion

[ppm]

[Hz] of cation

[ppm]

of anion

[ppm]

2a^[a,b]1.69

2b^[c]1.36

63

55

65

66

45

52

57

52

–

64

–

1.55

1.42

1.54

1.35

2.15

2.17

2.18

2.16

–

14.9

–

430

–

550

360 24.3

420 24.2

–

63.9

63.4

30.2

30.5

241

56

–

142

–

75

97

168

–

29

87

86

82

62.4 (br)

–

ꢀ159.4 (br)

2c

2d

1.36

1.44

13.5

3a^[a,d]1.36

113 15.2

116 16.6

117 12.3 (s)

116 14.0

107 33.2 (s)

930 79.2 (br)

930 56.0 (br)

ꢀ253.3 (br) 63.6

ꢀ243.6 (br) 63.0

3b

3c

3d

1.61

1.30

1.42

–

21.9 (s)

–

ꢀ143.4 (br) ꢀ254.9 (br) 31.2

ꢀ164.9 (br) ꢀ247.4 (br) 30.6

510 24.4 (s)

4a^[a,b]1.92

–

44.5 (s)

45.2 (s)

45.4 (s)

–

ꢀ249.6 (br) 62.5

ꢀ246.4 (br) 61.9

4b

4c

4d

5a^[a]

2.12

1.96

2.07

–

34.3 (s)

32.7 (s)

79.9 (br)

ꢀ121.1 (br) ꢀ248.1 (br) 30.6

107 33.0

133.6 (s)

475 45.3

145.8 (s)

900 ꢀ128.1 (br) ꢀ251.8 (br) 30.2

ꢀ45.6 (br) ꢀ318.6 (s) 63.2

–

1

[a] From Ref. [27]. [b] In CDCl₃. [c] In CD₃CN. [d] From Ref. [27a] except for the J_CSncoupling constants.

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Table 2. Relevant NMR data for Pt complexes 1a, 1b, 9a–c and 10a–c in CD₂Cl₂.

1

d ¹H SnCH₃,

SnCH₂

²J_HSnd ¹H SnCH₃,

[Hz] SnCH₂

²J_HSn

[Hz] SnCH₂

d

¹³C SnCH₃,

¹J_CSn

[Hz] SnCH₂

d

¹³C SnCH₃,

¹J_CSn

[Hz] ¹¹⁹Sn^[a][Hz] ¹¹⁹Sn^[b][ppm] [ppm]

[ppm] [ppm]

d

²J_PSn

d

³¹P

d

¹⁹⁵Pt ²J_CPtJ_PPtJ_SnPt

[a]

[b]

[a]

[b]

[Hz] [Hz] [Hz]

[ppm]

1a^[c]0.71

–

2.1 (s)

1.9

–

151.7 233 –

164.2 242 –

66.8 ꢀ5430.6 –

2873 7044

67.1 ꢀ5434.0 613 2924 7355

1b 0.78

9a 1.27

9b 1.36

9c 1.20

10a 1.94

10b 2.06

10c 1.89

36 1.54

54 1.46

59 1.52

58 2.16

–

117 11.5

116 12.8

118 9.1

108 31.1

–

530 23.9

500 23.6

500 23.8

450 44.5

–

950 ꢀ5.0

87 ꢀ254.1 58.5 ꢀ5165.0 139 2700 19201

85 ꢀ256.5 59.6 ꢀ5198.6 131 2780 18700

915 ꢀ21.4

–

ꢀ219.7 89 ꢀ259.1 27.1 ꢀ5025.0 –

2803 19819

900 ꢀ1.4

84 ꢀ258.2 58.1 ꢀ5166.7 131 2702 17732

2.15

30.5

29.3

44.3

44.5

–

ꢀ13.8

78 ꢀ260.7 59.2 ꢀ5200.8 –

2773 17370

ꢀ216.9 85 ꢀ259.1 27.0 ꢀ5025.3 114 2838 18694

[a] Cation. [b] Anion. [c] From Ref. [26] except for the ¹¹⁹Sn{¹H} data.

(0.78 ppm) with a platinum–hydrogen coupling of 67 Hz, as

well as by the ¹³C NMR signal (1.9 ppm) with a platinum–

carbon coupling of 613 Hz.

precludes the need to prepare, isolate, and purify individual

[Pd(P^N)₃] starting materials for each ligand of interest. In

a control experiment, 2-PyPPh₂derivative 3a was also success-

fully prepared by this method.

Over time, both 1a and 1b isomerise to methylstannylene

complexes 8a and 8b respectively [Eq. (7)], as evidenced by

comparison of the emerging signals with those of analogous

and structurally characterised methylstannylene platinum com-

plexes 9 (Table 2, see below). The appearance of a J_HSnof 53 Hz

1

in the methyl signal in H NMR, together with the disappear-

ance of the J_CPtin ¹³C NMR, is indicative of the transposition of

the methyl and one of the chlorides.

The new complexes 3b–d and 4b–d display a singlet in the

¹³P{¹H} NMR with a chemical shift comparable to that of related

tetrafluoroborate compounds 2b–d (Table 1). In most in-

The timescale of isomerization for these complexes is signifi-

cantly different (36 days for 1a, nine days for 1b), indicating

that the electronic nature of the ligand plays an important role

in this process, and that the less basic P-donor of 1b facilitates

the transposition of the methyl and chloride ligands. It also

suggests that the initial products 1a and 1b bearing the

methyl on platinum are kinetic in origin, whereas the methyl-

stannylenes 8a and 8b are the thermodynamic products. A

similar study for imidazolyl ligand c was hampered by the low

solubility of its Pt complex.

stances, these signals are accompanied by tin satellites (²J_PSn

=

29-168 Hz). The ¹¹⁹Sn{¹H} NMR spectra contain two broad

resonances in a 1:1 ratio corresponding to the palladium-

bound stannylene and the [SnCl₄R]^ꢀanion.

The presence of a direct SnꢀC bond in 3b–d follows from

2

1

the observation of a J_HSncoupling of 52–57 Hz in the H NMR

1

spectra for the methylstannylene groups, and a J_CSncoupling

constant (3b: 420 Hz, 3d: 510 Hz) in the H/¹³C{¹H}-HSQC ex-

1

periment.

The position of the methyl moiety close to the pyridyl group

in 3b is further evidenced by the observation of a correlation

between the methylstannylene and the a-pyridyl protons in

Reaction of RSnCl₃(R=Me, nBu, Ph) with Pd⁰precursors

1

the H-NOESY NMR spectrum (see the Supporting Information).

The synthetic strategy for the formation of new diphosphino-

stannylene–palladium complexes trans-[PdCl{(P^N)₂SnCl(R)}]

[SnCl₄R] (R=Me (3b–d), nBu (4b–d); Eq. (8)) starting from

a Pd⁰precursor was slightly altered from that reported previ-

ously for 3a, 4a, and 5a [Eq. (4)].^[27]In the new method,

[Pd(dba)(P^N)₂]^[34–36]is formed in situ by addition of two

equivalents of ligand to the palladium(0) precursor [Pd(dba)₂],

prior to the addition of the tin reagent [Eq. (8)]. This approach

The close proximity of the n-butylstannylene and [SnCl₄nBu]^ꢀ

signals in the ¹H and ¹³C NMR spectra of trans-

[PdCl{(P^N)₂(SnClnBu)}][SnCl₄nBu] (4b and 4c) prevents direct

2

1

determination of J_HSnor J_CSn. For 4d however, the signals for

the n-butyl signals are sufficiently separated to allow the

1

²J_HSn=64 Hz and J_CSn=475 Hz couplings for the a-CH₂group

of the n-butylstannylene to be determined. It has to be noted

that complex 4b in solution decomposes after prolonged

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times, as evidenced by emergence of signals typical for 1-

of the neutral complex compared to that of the cationic spe-

cies while in solution only 10c is observed.

1

butene and 1-chlorobutene in the H NMR spectrum.

The structural assignments of cationic alkyl stannylenes 3a,

3b, 4c, and 9a (Figure 3) as well as those of neutral stannyl

complexes 2’d, 5’a, and 10’c (Figure 4) were confirmed by

single-crystal X-ray structure determinations (Table 3). In all of

the complexes, the angles about palladium or platinum are

consistent with a square-planar geometry at the transition

metal centre. The tin centres in 3a, 3b, 4c, and 9a are five-co-

ordinate with limited variation in their SnꢀCl distances. The

geometries are best described as trigonal bipyramidal, but all

of the complexes show a significant distortion towards square

pyramidal. In the neutral complexes (2’d, 5’a, and 10’c) the tin

centres are in an octahedral environment. All of these com-

plexes show a slight distortion of the bond angles involving

the chlorides due to their weak binding (see below).

Reaction of RSnCl₃(R=Me, nBu) with Pt⁰precursors

To compare with the corresponding reaction for Pd, reactions

of RSnCl₃with [Pt(dba)₂] in the presence of ligands a–c were

carried out affording the organostannylene complexes trans-

[PtCl{(P^N)₂(SnCl(R))}][SnCl₄R] (R=Me, 9a–c; R=nBu, 10a–c) in

high yields [Eq. (9)].

The SnꢀC bond lengths are in the range 2.127(4)–2.148(3) ꢁ

for the cationic complexes and 2.154(4)–2.187(3) ꢁ for the neu-

tral complexes. The difference can at least partly be explained

by the increase in coordination number around tin.^[41]

For the ionic and neutral Pd complexes the SnꢀN distances

involving the pyridyl ligands are longer (2.351(2)–2.398(3) ꢁ

and 2.408(3)–2.472(3) ꢁ, respectively) than those involving the

imidazolyl ligands (2.3176(17)–2.3268(17) ꢁ and 2.309(3)–

2.376(2) ꢁ, respectively). This is in line with the higher field

shift of the stannylene moiety in the ¹¹⁹Sn NMR of the imid-

azolyl derivatives (Tables 1 and 2) and suggests a greater

donor strength of the N-heterocycle.

The spectroscopic data for complexes 9 and 10 are collected

in Table 2. Noteworthy are the ¹⁹⁵Pt{¹H} NMR spectra in which

a triplet between ꢀ5025.0 and ꢀ5200.8 ppm is observed with

well-resolved tin satellites (¹J_PtSn=17370–19819 Hz). The PtꢀSn

coupling constants are comparable to that in trans-

[PtCl(SnCl₂Me)(PPh₃)₂] (19982 Hz)^[39]but smaller than the one in

PtꢀMe derivative 1a (7044 Hz). In the ¹¹⁹Sn NMR spectra, sharp

triplets with platinum satellites between ꢀ1.4 and ꢀ21.4 ppm

for the pyridyl derivatives and at higher field for the imidazolyl

derivatives (d=ꢀ216.9–ꢀ219.7) correspond to the stannylene

moiety while the anion appears upfield between ꢀ254.1 and

ꢀ260.7 ppm. For comparison, the ¹¹⁹Sn NMR spectrum of 1a

displays a single resonance at 151.7 ppm (t, ²J_SnP=233 Hz,

¹J_SnPt=7044 Hz). This downfield ¹¹⁹Sn NMR shift for the stanny-

lene in 1a relative to that in 9 and 10 highlights the sensitivity

of the tin atom to substituent effects and further supports the

correct isomeric assignment of 9 and 10.^[36–38]

X-ray crystal structure determinations of 2’d, 3a, 3b, 4c, 5’a,

9a, and 10’c

All of the obtained crystal structures contained solvent mol-

ecules, in most cases with a large degree of disorder (see the

Experimental Section). For the sake of clarity, the solvent is dis-

regarded in the numbering of the structures. Efforts to obtain

single crystals of the new compounds led in some cases to iso-

lation of the neutral rather than the ionic species. Attempted

isolation of complex 2d from a crude reaction mixture gave

rise to the isolation of the neutral chloride derivative

[PdCl{(d)₂(SnCl₂Me)}] (2’d), which is due to incomplete chloride

abstraction. In the case of 5a, the neutral complex (5’a) could

be obtained by reacting the [Pd⁰(P^N)₂] precursor formed in

situ with only one equivalent of PhSnCl₃.^[27b]Neutral complex

[PtCl{(c)₂(SnCl₂Bu)}] (10’c) resulted owing to the lower solubility

Figure 3. Displacement ellipsoid plots (50% probability) of

[PdCl{(a)₂(SnClMe)}][SnCl₄Me] (3a), [PdCl{(b)₂(SnClMe)}][SnCl₄Me] (3b, only

one of two independent molecules is depicted), [PdCl{(c)₂(SnClnBu)}]

[SnCl₄nBu] (4c), and [PtCl{(a)₂(SnClMe)}][SnCl₄Me] (9a). H atoms, (disordered)

solvent molecules, and anions are omitted for the sake of clarity.

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observed. The PtꢀSn bond of 9a is shorter than that of struc-

tural isomer 1a (2.5166(6) ꢁ).^[26]

The number of known Group 10 metal complexes contain-

ing a MꢀSn bond is limited. However, the PdꢀSn bond lengths

in 3a and 3b are close to those in neutral Pd stannylene com-

plexes

[PdCl{2-(Me₂NCH₂C₆H₄)}{SnCl(2,6-(Me₂CH₂)₂C₆H₃)}]

and [Pd{Sn(CH(SiMe₃)₂)₂}(iPr₂PC₂H₄PiPr₂)]

(2.4956(8) ꢁ)^[42]

(2.481(2) ꢁ)^[43]while the PdꢀSn bond in 4c is closer to that in

[Pd(PPh₃){(1-methyl-2-mercaptoimidazole)₂(SnCl₂)}]

(2.5382(1) ꢁ).^[28c]The PdꢀSn bond in 2’d is significantly longer

and approaches that of the trichlorostannyl species cis-

[PdCl(SnCl₃)(PPh₃)₂] (2.5760(7) ꢁ).^[44]

Concerning the electronic structure of these cationic bimet-

allic MꢀSn species, assigning the oxidation state of the tin and

Group 10 atom is not unambiguous as the bonding mode can

!

be described by several resonance structures: [M^{II +}Sn^II], [M^Iꢀ

Sn^{III +}], and [M⁰!Sn^{IV +}].^[28,29]By referring to our complexes as

“stannylenes”, we do not intend to favour either of these

hypothetical extremes. Rather we want to simply discriminate

between species carrying a SnCl₂or a SnClR unit versus those

that carry a stannyl group (SnCl₃or SnCl₂R).

The SnꢀCl bond lengths in neutral organodichlorostannyl

species 2’d, 5’a, and 10’c are relatively long and sensitive to

packing effects, while they are unexceptional in the other com-

plexes. The Pd1, Sn1, Cl1, C1, and Cl3 atoms in 2’d, 5’a, and

10’c are equiplanar, as evidenced by a least-squares analysis of

the plane defined by these atoms. None of the atoms deviate

more than 0.068 ꢁ from the coordination plane.

Figure 4. Displacement ellipsoid plots (50% probability) of

[PdCl{(d)₂(SnCl₂Me)}] (2’d, only the major disorder form of the CF₃groups is

shown; only one of two independent molecules is depicted),

[PdCl{(a)₂(SnCl₂Ph)}] (5’a, only one of two independent molecules is depict-

ed), and [PtCl{(c)₂(SnCl₂Bu)}] (10’c). H atoms and (disordered) solvent mol-

ecules are omitted for the sake of clarity.

The N-heterocycle donor strength influences the PdꢀSn

bond length as well, with the pyridyl derivatives 3a and 3b

having shorter PdꢀSn bonds (2.5026(3) and 2.5039(4) ꢁ) than

the imidazolyl derivative 4c (2.5265(2) ꢁ). For the neutral Pd

complexes 5’a and 2’d (PdꢀSn=2.5249(3) and 2.5597(3) ꢁ, re-

When considered as tin complexes bearing an N-M-N pincer

ligand, the geometry around tin in complexes 3a, 3b, 4c, and

9a is reminiscent of trigonal bipyramidal structures of dialkyl

tin species R₂SnX₃(X=heteroatom donor) where the axial pos-

itions are usually occupied by X with one X and two alkyl lig-

spectively) and the two platinum complexes 9a and 10’c (Ptꢀ ands positioned in the equatorial plane.^[45,46]In the complexes

Sn=2.5060(2) and 2.5461(2) ꢁ, respectively) the same trend is

studied herein, one of the alkyl ligands has been replaced by

Table 3. Selected bond lengths and angles for 3a, 3b, 4c, 9a, 2’d, 5’a and 10’c.

3a

3b^[a]

4c

9a

2’d^[a]

5’a^[a]

10’c

Bond lengths [ꢁ]

M–P1

M–P2

M–Cl2

M–Sn1

Sn1–N1

Sn1–N2/3

Sn1–C1

Sn1–Cl1

Sn1–Cl3

2.3031(8)

2.2913(8)

2.3810(7)

2.5026(3)

2.354(2)

2.385(2)

2.141(3)

2.3832(8)

–

2.2822(10)

2.2817(10)

2.3676(10)

2.5039(4)

2.360(3)

2.398(3)

2.127(4)

2.3788(11)

–

2.2989(5)

2.2914(5)

2.3795(5)

2.52648(19)

2.3176(17)

2.3268(17)

2.148(3)

2.3733(6)

–

2.2855(6)

2.2779(6)

2.3818(6)

2.5060(2)

2.351(2)

2.373(2)

2.133(2)

2.3814(7)

–

2.2923(9)

2.2891(9)

2.4106(9)

2.5597(3)

2.360(3)

2.309(3)

2.187(3)

2.6744(11)

2.4952(12)

2.2793(9)

2.2839(9)

2.4003(9)

2.5249(3)

2.408(3)

2.472(3)

2.154(4)

2.6264(10)

2.5588(10)

2.2791(6)

2.2708(6)

2.4002(6)

2.5461(2)

2.376(2)

2.354(2)

2.173(2)

2.8166(7)

2.5012(8)

Bond angles [8]

P1-M-P2

172.48(3)

174.88(2)

110.22(2)

138.77(9)

168.09(8)

110.99(9)

–

173.04(4)

177.10(3)

117.17(3)

136.76(13)

169.87(12)

106.01(13)

–

174.951(18)

177.975(16)

111.728(19)

138.37(7)

165.60(6)

109.90(7)

–

173.74(2)

176.370(16)

109.836(18)

139.26(8)

169.36(7)

110.88(8)

–

177.80(4)

177.05(3)

83.72(2)

169.57(12)

173.85(12)

85.92(12)

94.96(12)

95.46(3)

177.93(4)

176.20(3)

83.47(2)

175.37(12)

169.52(10)

92.14(12)

94.48(11)

89.91(3)

175.39(2)

178.104(18)

85.327(14)

166.57(8)

173.65(8)

81.28(8)

Cl2-M-Sn1

M-Sn1-Cl1

M-Sn1-C1

N1-Sn-N2/3

Cl1-Sn-C1

C1-Sn-Cl3

M-Sn-Cl3

97.47(8)

95.960(19)

–

[a] Only one of two independent molecules is given.

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the Group 10 metal. There is also some analogy with ionic aryl

(dimethyl)tin bromide 11 where the rigid tridentate NCN

ligand is performing a similar role as the NMN (M=Pd, Pt)

ligand in the Group 10 complexes studied here (Figure 5).^[46]

The octahedral geometry of tin and the trans-Pd-Sn-R arrange-

ment in 2’d, 5’a, and 10’c can be compared to the often pre-

ferred trans-R-Sn-R arrangement in R₂SnX₂(L)₂complexes (X=

halide, L=neutral 2e donor).^[46]

ands a–d. This mirrors reactivity trends established by Eaborn

and Al-Allaf^[47,48]for the addition of RSnCl₃(R=Me, Ph,

C₂H₄CO₂Me, C₂H₄CO₂Et) to Pt⁰and our observations in an

analogous reaction between MeSnCl₃and [Pd(PPh₃)₄] in the ab-

sence of a P^N ligand.^[27]However, for BuSnCl₃the P^N ligands

clearly provides additional stability to the n-butylstannylene

products trans-[MCl{(P^N)₂(SnClnBu)}][SnCl₄nBu], allowing the

isolation of these complexes. This became apparent when

nBuSnCl₃was reacted with [Pd(PPh₃)₄] resulting in a rapid de-

hydrostannylation reaction to form Pd hydrides, SnCl₂and bu-

tenes, preventing the isolation of alkyl stannylene species.^[27]

Furthermore, tin dichloride is known to insert into the PtꢀCl

bond of [PtClMe(PPh₃)₂]^[40]or the PdꢀC bond of

[PdClMe(PPh₃)₂],^[27]

to

give

[PtMe(SnCl₃)(PPh₃)₂]

or

[PdCl(SnCl₂Me)(PPh₃)₂] respectively, which is consistent with

the results presented here [Eqs. (1–3), (5), and (6)]. The pres-

ence of P^N ligands does however lead to a more stable and

rigid structure through the formation of a self-assembled P-Sn-

P pincer ligand. The N!Sn interaction enforces a trans-config-

uration at the transition-metal centre, preventing MꢀP bond

(M=Pd or Pt) rotation and favouring chloride abstraction from

the SnCl₂X moiety (X=Cl or organic group). In the synthesis of

1a and 1b, this N!Sn interaction also disfavours [SnCl₃]^ꢀdis-

sociation.

Figure 5. Structural analogy between the reported complexes (NMN pincer,

R=alkyl or chloride) and bis(N,N-dimethylaminomethyl)phenyl(dialkyl) tin

bromides (NCN pincer).

Discussion

Diphosphinostannylene complexes trans-[MCl{(P^N)₂(SnCl(R))}]

[X] (M=Pd, Pt; P^N=a–d; R=Me, nBu, Ph; [X]^ꢀ=[BF₄]^ꢀ,

[SnCl₄R]^ꢀ) containing a SnCl(R) stannylene moiety are readily

obtained through either 1) the addition of SnCl₂to

[PdClMe(P^N)₂], either prepared in situ or prepared before-

hand, followed by Cl^ꢀabstraction; or 2) addition of organotin

trichlorides to [M(P^N)_n] prepared in situ. In contrast, SnCl₂ad-

dition to [PtClMe(P^N)₂] prepared in situ followed by Cl^ꢀab-

straction results in methylplatinum derivatives 1a and 1b that

slowly convert into alkyl stannylene derivatives 8.^[26]The metal

complexes containing the trifluoromethylated ligands b and d

generally show superior solubility over the analogous non-

fluorinated species, improving the ease and accuracy of spec-

troscopic characterization.

Next to direct insertion of SnCl₂in the PdꢀC bond (step (i),

Scheme 2), an alternative mechanism of formation for diphos-

phinostannylene complexes trans-[PdCl{(P^N)₂(SnCl(R))}][BF₄]

Neither the relative donor strength of the nitrogen substitu-

ent (imidazole>pyridyl) nor the trifluoromethyl substitution af-

fects the selectivity of the reactions observed. However, evi-

dence of an increased N!Sn donor interaction in the case of

imidazolyl ligands b and d was attained by ¹¹⁹Sn{¹H} NMR spec-

troscopy and the crystal structure determination of the palla-

dium species. The stannylene resonance of imidazolyl deriva-

tives 2d, 3c, 3d, 4c, and 4d was shifted upfield (d=ꢀ121.1–

ꢀ164.9 ppm) relative to those containing a pyridyl donor (2b,

3a, 3b, and 4b; d=56.0–84.5 ppm), indicative of increased

shielding of the stannylene centre by the stronger donating

imidazolyl donor.^[35–37]An increased imidazolyl–stannylene in-

teraction was further supported by a shorter nitrogen–tin

bond in the crystal structure of cationic complex 4c relative to

the pyridine derivatives 3a and 3b.

Scheme 2. Alternative pathways to diphosphinostannylene complexes A in-

volving alkyl transfer via intermediate B. See the text for details.

(2a–d) can be envisioned. Tin dichloride is known to insert

into PdꢀCl bonds if no alkyl group is present on the transition

metal centre,^[49]and for platinum this occurs even when there

is a metal–alkyl bond, as was observed in the formation of

trans-[PtMe{(a)₂(SnCl₂)}][BF₄] (1a). This suggests that the first

step in the formation of trans-[PdCl{(P^N)₂(SnClMe)}][BF₄] (2a–

d) could also be SnCl₂insertion into the PdꢀCl bond followed

by Cl^ꢀelimination (step (ii)). From intermediate B, alkyl–chlor-

ide exchange between palladium and tin would give A (step

(iii)).

In general, the use of P^N ligands in these reactions did not

change the reactivity trend relative to systems with traditional

ligands. The present study shows an apparent SnꢀCl oxidative

addition pathway for the reaction of RSnCl₃(R=Me, nBu, Ph)

with either palladium(0) or platinum(0) in the presence of lig-

Furthermore, addition of RSnCl₃to [Pd(P^N)₂] (generated in

situ) could result in direct SnꢀCl bond activation (step (iv)) or

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ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

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are reported in the Supporting Information. All other reagents

were purchased form Sigma–Aldrich, except nBuSnCl₃, which was

provided by Arkema B.V. Location Vlissingen. NMR data were rec-

orded on a Varian MRF 400 or on a Varian VNMRS 400 and chem-

ical shifts are reported in ppm relative to the residual solvent sig-

nals (¹H, ¹³C), external H₃PO₄85% in water (³¹P), external neat CFCl₃

(¹⁹F), external SnMe₄(1m, ¹¹⁹Sn) in benzene, external BF₃·OEt₂(¹¹B),

or external K₂[PtCl₆] 1m in water (¹⁹⁵Pt). The general numbering

scheme used for the labelling of the protons and carbons associat-

ed with the phosphine ligand is shown in Figure 6. High-resolution

SnꢀC oxidative addition (step (v)) followed by rearrangement

of B to A (step (iii)). However, B is not observed in the oxidative

addition reactions. As conversion of B to A is slow for M=Pt,

direct SnꢀC bond oxidative addition appears unlikely in this

case.

The observed alkyl transfer from the Group 10 metal centre

to tin upon SnCl₂addition is an interesting one. It could mean

that the role of SnCl₂as co-catalyst in palladium- and plat-

inum-based catalytic systems may be different from previous

propositions in which SnCl₂is believed to lead to the forma-

tion of a SnCl₃ligand that serves as a weakly coordinating

anion and/or as a trans-labilising ligand.^[8,22–25]Based on the ob-

servations in this study, it is conceivable that an alkyl group on

palladium can transfer to the tin centre of the trichlorostannyl

ligand during a catalytic reaction (analogous to step (iii)) to

form a more stable resting state that cannot undergo b-H elim-

ination. To the best of our knowledge, such a possibility has

not been previously observed or suggested in the context of

catalysis by Group 10 metal complexes. Mechanistically such

an alkyl transfer reaction may be related to the 1,2 alkyl shift

observed for alkyl silylene species in the Glaser–Tilley alkene

hydrosilylation.^[50–52]This will be the subject of future investiga-

tions.

Figure 6. General numbering scheme for carbon atoms and protons of phos-

phine ligands a–d used for the spectroscopic assignment of all of the com-

pounds.

mass spectroscopy (HRMS) was performed on a Waters LCT Prem-

ier XE micromass instrument using the electrospray ionisation tech-

nique in positive mode (ESI-HRMS). Several attempts to obtain ac-

curate elemental analyses data for the new compounds failed des-

pite recrystallization of the compounds before analysis (probably

because digestion is hampered by the high heteroatom content

and the ionic nature of these compounds), but high-resolution

mass spectra were obtained to compensate for this.

Conclusion

We have demonstrated that addition of RSnCl₃(R=Me, nBu,

Ph) to [Pd(P^N)_n] or [Pt(P^N)_n] gives organostannylene com-

plexes of the general formula trans-[MCl{(P^N)₂(SnCl(R))}]

[SnCl₄R] by SnꢀCl bond activation. The addition of SnCl₂to

[MClMe(P^N)₂] leads to initial apparent insertion of SnCl₂into

the PtꢀCl or PdꢀC bonds to give trans-[PtMe{(a)₂(SnCl₂)}][BF₄]

1a or trans-[PdCl{(P^N)₂(SnClMe)}][BF₄] 2, respectively (follow-

ing chloride abstraction). For platinum, slow isomerization to

the methylstannylene species was observed, leading to prod-

ucts analogous to 2. The generality of these reactions for both

palladium and platinum has been demonstrated through the

use of different P^N ligands. The formation of organostanny-

lene or organostannyl species upon addition of SnCl₂has not

been previously observed and these species may be respon-

sible for the improved selectivity observed in Group 10 SnCl₂-

catalysed processes. Further studies into the mechanism of

alkyl transfer are in progress.

trans-[PdCl{(b)₂(SnClMe)}][BF₄] (2b): Ligand b (441 mg, 1.1 mmol,

2.25 equiv) in THF (3 mL) was added to a Schlenk flask containing

[PdClMe(COD)] (130 mg, 0.49 mmol). After the mixture was stirred

for 1 h, SnCl₂(102 mg, 0.54 mmol, 1.1 equiv) in THF (3 mL) was

added. After 20 min, Ag[BF₄] (95 mg, 0.49 mmol, 1 equiv) in THF

(3 mL) was slowly added to the orange–brown solution, and the

mixture was stirred in the dark for an additional 20 min before re-

moving AgCl by filtration. The solvent was removed from the

supernatant and the resulting white powder was washed with

ether (3ꢂ10 mL). trans-[PdCl{(b)₂(SnClMe)}][BF₄] (2b) (351 mg,

0.29 mmol, 60% yield) was obtained as a white solid after precipi-

tation from a concentrated acetonitrile (3 mL) solution with ether

1

(15 mL). H NMR (399.80 MHz, CD₃CN): d=9.16 (d, J_HH=5.0 Hz, 2H,

H₁₁), 8.29 (t, J_HH=7.5 Hz, 2H, H₉), 8.09–7.74 (m, 20H, H₂, H₄, H₅, H₆,

H₈, H₁₀), 1.40 ppm (s, ²J_HSn=55 Hz, 3H, SnClCH₃). ¹³C{¹H} NMR

1

(100.54 MHz, CD₃CN): d=151.0 (t, ³J_CP=9 Hz, C₁₁), 147.8 (t, J_CP

=

3

2

33 Hz, C₇), 143.8 (t, J_CP=2 Hz, C₉), 138.9 (broad, C₆), 133.6 (t, J_CP

3

6 Hz, C₈), 132.8–131.8 (m, C₂,C₃), 131.7 (t, J_CP=5 Hz, C₅), 131.0 (s,

1

C₁₀), 130.7 (broad, C₄), 130.4–130.1 (m, C₇), 125.1 (q, J_CF=272, CF₄),

14.9 ppm (s, ¹J_CSn=430 Hz, SnClCH₃). ³¹P{¹H} NMR (161.85 MHz,

CD₃CN): d=63.4 ppm (s, ²J_PSn=56 Hz). ¹¹B{¹H} NMR (128.27 MHz,

CD₃CN): d ꢀ1.1 ppm (s). ¹⁹F{¹H} NMR (376.15 MHz, CD₃CN): d=

ꢀ63.5 (s, CF₃), ꢀ151.7 ppm (s, BF₄). ¹¹⁹Sn{¹H} NMR (149.07 MHz,

CD₃CN): d=62.4 ppm (broad, w_1/2=165 Hz). HRMS (ESI): exact

mass (monoisotopic) calcd for C₃₉H₂₇Cl₂F₁₂N₂P₂PdSn, 1108.8894;

found, 1108.8895.

Experimental Section

Unless otherwise noted, all reactions and manipulations were per-

formed under a nitrogen atmosphere in a glovebox or using con-

ventional Schlenk techniques. All nondeuterated solvents were

dried using an MBraun SPS-800 solvent purification system and de-

gassed prior to use, except dichloromethane and THF, which were

dried prior to distillation over CaH₂and Na/benzophenone,

respectively. [D₂]Dichloromethane and [D]chloroform were dried

over CaH₂, and [D₃]acetonitrile was dried over 4 ꢁ molecular sieves

trans-[PdCl{(c)₂(SnClMe)}][BF₄] (2c): THF (5 mL) was added to

a Schlenk flask containing [Pd(Cl)Me(COD)] (100 mg, 0.377 mmol),

ligand c (226 mg, 0.849 mmol, 2.25 equiv), tin dichloride (86 mg,

0.46 mmol, 1.2 equiv) and [NnBu₄][BF₄] (210 mg, 1.14 mmol,

3 equiv), and the resulting yellow suspension was stirred for 1.5 h.

trans-[PdCl{(c)₂(SnClMe)}][BF₄] (2c) (249 mg, 0.268 mmol, 70% yield)

prior

to

distillation.

[PdClMe(COD)],^[53]

[PtClMe(COD)],^[54]

[Pt(dba)₂],^[55]Cl₂PNEt₂,^[56]and 2-(diphenylphosphino)-N-methyl-

imidazole^[30]were prepared according to previously reported

methods. Experimental details for the synthesis of ligands b and d

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ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

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1

was obtained as a light yellow powder after filtration and washing

with THF (4ꢂ10 mL). ¹H NMR (399.80 MHz, CD₂Cl_2):d=7.71–7.66

(m, 8H, H₂, H₆), 7.59 (t, J_HH=7.2 Hz, 4H, H₄), 7.53 (broad, 2H, H₉),

7.52–7.48 (m, 8H, H₃, H₅), 7.45 (s, 2H, H₈), 3.21 (s, 6H, N-CH₃),

(64%, 351 mg, 0.346 mmol). H NMR (399.80 MHz, CD₂Cl₂): d=9.42

(d, J_HH=5.2 Hz, 2H, H₁₁), 8.19 (t, J_HH=7.6 Hz, 2H, H₁₀), 7.93–7.87 (m,

4H, H₈, H₉), 7.62 (t, J_HH=7.2 Hz, 4H, H₄), 7.54 (t, J_HH=7.4 Hz, 8H, H₃,

2

3

H₅), 7.46–7.41 (m, 8H, H₂, H₆), 0.82 ppm (t, J_HPt=72 Hz, J_HP=6.8 Hz

3H, PtCH₃). ¹³C{¹H} NMR (100.54 MHz, CD₂Cl₂): d=149.3 (t, J_CP

6.8 Hz, C₁₁), 145.9 (t, J_CP=35 Hz, C₇) 142.1 (s, C₁₀), 133.6 (t, J_CP

7 Hz, C₂, C₆), 132.6 (s, C₄), 130.3 (t, J_CP=6.5 Hz, C₈), 129.6 (t, J_CP

2

3

1.40 ppm (s, J_HSn=65 Hz, 3H, SnClCH₃). ³¹P{¹H} NMR (161.85 MHz,

=

CD₂Cl₂): d=30.2 ppm (s). ¹⁹F{¹H} NMR (376.15 MHz, CD₂Cl₂): d=

ꢀ154.8 ppm (s). HRMS (ESI): exact mass (monoisotopic) calcd for

C₃₃H₃₃Cl₂N₄P₂PdSn: 842.9615; found: 842.9628.

2

3

5.3 Hz, C₃, C₅), 128.6 (s, C₉), 126.1 (t, J_CP=28 Hz, C₁), 0.72 ppm (s,

PtCH₃). ¹⁹F{¹H} NMR (376.15 MHz, CD₂Cl₂): d=ꢀ153.029 ppm (s,

trans-[PdCl{(d)₂(SnClMe)}][BF₄] (2d): Ligand d (333 mg, 0.83 mmol,

2.25 equiv) in THF (3 mL) was added to a Schlenk flask containing

[Pd(Cl)Me(COD)] (98 mg, 0.37 mmol). The mixture was stirred for

1 h before the addition of SnCl₂(77 mg, 0.41 mmol, 1.1 equiv) in

THF (3 mL). After 20 min, Ag[BF₄] (72 mg, 0.37 mmol, 1 equiv) in

THF (3 mL) was slowly added to the orange–brown solution, and

the mixture was stirred in the dark for an additional 20 min before

AgCl was removed by filtration. Concentration of the reaction mix-

ture under reduced pressure followed by washing with diethyl

ether (3ꢂ10 mL) gave a white powder. The sample was dissolved

in 2 mL acetonitrile and addition of ether (30 mL) gave trans-

[PdCl{(d)₂(SnClMe)}][BF₄] (2d) (308 mg, 0.26 mmol, 70% yield) as

BF₄). ³¹P{¹H} NMR (161.85 MHz, CD₂Cl₂): d=66.0 ppm (s, J_PPt

=

2876 Hz, ²J_PSn=231 Hz). ¹¹⁹Sn{¹H} NMR (149.07 MHz, CD₂Cl₂): d=

151.7 ppm (t,

_SnPt=7044 Hz, ²J_SnP=234 Hz). ¹⁹⁵Pt{¹H} NMR

_PtP=2875 Hz). HRMS

J

(85.94 MHz, CD₂Cl₂): d=ꢀ5430.6 ppm (t,

J

(ESI): exact mass (monoisotopic) calcd for C₃₅H₃₁N₂P₂PtSnCl₂:

924.9998; found: 924.9967.

Isomerization of 1a to 8a: A deuterated CH₂Cl₂solution (0.5 mL) of

1a (10.1 mg, 0.01 mmol) was monitored by H and ³¹P NMR, which

1

showed the isomerization reaching completion after 40 days by

comparison of the spectral data with those of analogous complex

9a (see below).

1

a white solid. H NMR (399.80 MHz, CD₃CN): d=8.08–8.04 (m, 4H,

[PtMe{(b)₂(SnCl₂)}][BF₄] (1b): [PtClMe(COD)] (154 mg, 0.44 mmol)

and b (610 mg, 1.53 mmol, 3.5 equiv) were dissolved in dichloro-

methane (10 mL). After the mixture was stirred for 1 h, tin dichlor-

ide (90 mg 0.47 mmol, 1.1 equiv) was added to the yellow suspen-

sion. After the resulting yellow solution was stirred for 30 min, a so-

lution of Ag[BF₄] (99 mg, 0.51 mmol, 1.1 equiv) in dichloromethane

(8 mL) was added to the reaction mixture, whereupon the immedi-

ate formation of a white precipitate was observed. The mixture

was then filtered, concentrated in vacuo and the yellow oily resi-

due was washed with diethyl ether (3ꢂ15 mL) and hexane (3ꢂ

15 mL), yielding the product [PtMe{(b)₂(SnCl₂)}][BF₄] (1b) as a white

H₂), 7.97 (d, J_HH=7.5 Hz, 4H, H₄), 7.89–7.83 (m, 4H, H₆), 7.75 (t,

J

_HH=7.5 Hz, 4H, H₅), 7.66 (s, 2H, H₉), 7.62 (s, 2H, H₈), 3.26 (s, 6H, N-

CH₃), 1.44 ppm (s, ²J_HSn=66 Hz, 3H, SnClCH₃). ¹³C{¹H} NMR

(100.54 MHz, CD₃CN): d=137.9 (t, ³J_CP=6 Hz, C₆), 137.4 (t, J_CP

36 Hz, C₇), 135.5 (s, C₉), 132.6 (qt, J_CF=33 Hz, J_CP=6 Hz, C₃), 132.0

=

1

2

3

(t, J_CP=5 Hz, C₅), 131.7–131.5 (m, C₂), 130.9–130.8 (m, C₄), 129.2 (t,

³J_CP=9 Hz, C₈), 127.8 (t, J_CP=27 Hz, C₁), 125.0 (q, J_CF=272 Hz, CF₃),

37.8 (s, N-CH₃), 13.5 ppm (s, ¹J_CSn=550 Hz, SnClCH₃). ³¹P{¹H} NMR

(161.85 MHz, CD₃CN): d=30.5 ppm (s, ²J_PSn=142 Hz). ¹¹B{¹H} NMR

(128.27 MHz, CD₃CN): d=4.1 (s). ¹⁹F{¹H} NMR (376.15 MHz, CD₃CN):

d=ꢀ63.6 (s, CF₃), ꢀ151.8 ppm (s, BF₄). ¹¹⁹Sn{¹H} NMR (149.07 MHz,

CD₃CN): d=ꢀ159.4 ppm (broad, w_1/2=472 Hz). HRMS (ESI): exact

mass (monoisotopic) calcd for C₃₇H₂₉Cl₂F₁₂N₄P₂PdSn: 1114.9111;

found: 1114.9119.

1

solid (77%, 429 mg, 0.33 mmol). H NMR (399.80 MHz, CD₂Cl₂): d=

9.48 (s, 2H, H₁₁), 8.31 (br, 2H, H₁₀), 8.02–7.68 (br, 20H, H₂, H₄, H₅, H₆,

H₈, H₉), 0.78 ppm (t, ²J_HPt=67 Hz, ³J_HP=6 Hz, 3H, PtCH₃). ¹³C{¹H}

NMR (100.54 MHz, CD₂Cl₂): d=150.0 (s, C₁₁), 146.2 (t, J_CP=33 Hz,

C₇), 143.1 (s, C₁₀), 136.8 (s, C₆), 132.1 (q, ²J_CF=34 Hz, C₃), 131.0–

129.7 (br, C₂, C₄, C_5,C₈, C₉), 126.7 (br, C₁), 123.2 (q, J_CF=273 Hz, CF₃),

1.9 ppm (s, J_CPt=613 Hz, PtCH₃). ¹⁹F{¹H} NMR (376.4 MHz, CD₂Cl₂):

d=ꢀ63.5 (s, CF₃), ꢀ152.3 ppm (s, BF₄). ³¹P{¹H} NMR (161.85 MHz,

A

crude sample of what was believed to be trans-

[PdCl{(d)₂(SnClMe)}][BF₄] (2d) (107 mg, 0.0890 mmol) was recrystal-

lised by slow solvent diffusion of diethyl ether (10 mL) into a con-

centrated acetonitrile (2 mL) solution to give X-ray quality crystals.

The isolated product was found to be the neutral species trans-

[PdCl{(d)₂(SnCl₂Me)}] (2’d) (60 mg, 0.0521 mmol) resulting from in-

complete chloride exchange. ¹H NMR (399.80 MHz, CD₃CN): d=

CD₂Cl₂): d=67.1 ppm (s,

J

_PPt=2924 Hz, ²J_PSn=229 Hz, PtMe).

¹¹⁹Sn{¹H} NMR (149.07 MHz, CD₂Cl₂): d=164.2 ppm (t, J_SnPt

=

7355 Hz, ²J_SnP=242 Hz). ¹⁹⁵Pt{¹H} NMR (85.94 MHz, CD₂Cl₂): d=

ꢀ5434.0 ppm (t, J_PtP=2924 Hz, J_Pt117Sn=7029 Hz, J_Pt119Sn=7354 Hz).

8.25 (t, J_HP=5.9 Hz, 4H, H₂), 7.99–7.94 (m, 4H, H₆), 7.87 (d, J_HH

=

HRMS

(ESI):

exact

mass

(monoisotopic)

calcd

for

7.8 Hz, 4H, H₄), 7.78 (t, J_HH=7.8 Hz, 4H, H₅), 7.65 (s, 2H, H₉), 7.57 (s,

2H, H₈), 3.24 (s, 6H, N-CH₃), 1.73 ppm (s, ²J_HSn=90 Hz, 3H,

C₃₉H₂₇N₂P₂F₁₂PtSnCl₂, 1196.949; found, 1196.948.

3

SnClCH₃). ¹³C{¹H} NMR (100.54 MHz, CD₃CN): d=137.9 (t, J_CP=6 Hz,

Isomerization of 1b to 8b: A deuterated CH₂Cl₂solution (0.5 mL)

of 1b (12.8 mg, 0.01 mmol) was monitored by ¹H and ³¹P NMR,

which showed the isomerization reaching completion in nine days

by comparison of the spectral data with those of analogous com-

plex 9b (see below).

C₆), 137.0 (broad, C₇), 133.9 (s, C₉), 131.8–131.7 (m, C₃), 131.4 (t,

³J_CP=5 Hz, C₅), 130.0–129.9 (m, C₂, C₄), 129.6 (t, ¹J_CP=25 Hz, C₁),

3

1

128.9 (t, J_CP=9 Hz, C₈), 125.2 (q, J_CF=272 Hz, CF₃), 37.6 (s, N-CH₃),

23.4 ppm (s, SnCl₂CH₃). ³¹P{¹H} NMR (161.85 MHz, CD₃CN): d=

27.6 ppm (s). ¹⁹F{¹H} NMR (376.15 MHz, CD₃CN): d=ꢀ63.4 ppm (s,

CF₃).

trans-[PdCl{(b)₂(SnClMe)}][SnCl₄Me] (3b): Ligand

b

(991 mg,

2.48 mmol, 2.5 equiv) in toluene (5 mL) was added to a Schlenk

flask containing [Pd(dba)₂] (571 mg, 0.931 mmol). The mixture was

stirred for 1 h and a small amount of palladium black was removed

by cannula filtration. A solution of methyltin trichloride (528 mg,

2.20 mmol, 2 equiv) in toluene (5 mL) was added slowly to the

orange–brown solution to give a red solution with a light yellow

residue. After one hour the solvent was removed in vacuo. A pink

powder was obtained after trituration with hexane (3ꢂ10 mL) and

washing with hexane (3ꢂ10 mL). Toluene (10 mL) was added and

a precipitate was formed after the mixture was stirred for 16 h. Fil-

tration, followed by washing with toluene (3ꢂ10 mL) and hexane

(3ꢂ10 mL), gave trans-[PdCl{(b)₂(SnClMe)}][SnCl₄Me] (3b) (1.96 g,

[PtMe{(a)₂(SnCl₂)}][BF₄] (1a):^[26][PtCl(Me)(COD)] (192 mg, 0.54 mmol)

and a (370 mg, 1.41 mmol, 2.6 equiv) were dissolved in dichloro-

methane (10 mL). After the mixture was stirred for 1 h, tin dichlor-

ide (110 mg 0.58 mmol, 1.1 equiv) was added to the yellow suspen-

sion. After the resulting yellow solution was stirred for 30 min, a so-

lution of Ag[BF₄] (154 mg, 0.8 mmol, 1.5 equiv) in dichloromethane

(8 mL) was added to the reaction mixture, whereupon the immedi-

ate formation of a white precipitate was observed. The mixture

was then filtered, concentrated in vacuo and the orange residue

was washed with diethyl ether (3ꢂ15 mL) and hexane (3ꢂ15 mL),

yielding the product [PtMe{(a)₂(SnCl₂)}][BF₄] (1a) as an orange solid

Chem. Eur. J. 2015, 21, 1765 – 1779

www.chemeurj.org

1773

ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Full Paper

0.863 mmol, 86% yield) as

a

light yellow powder. ¹H NMR

trans-[PdCl{(b)₂(SnClnBu)}][SnCl₄nBu] (4b): Ligand

b

(806 mg,

(399.80 MHz, CD₂Cl₂): d=9.14 (d, J_HH=5.0 Hz, 2H, H₁₁), 8.24 (t, J_HH

=

2.0 mmol, 2.5 equiv) in toluene (5 mL) was added to a Schlenk flask

containing [Pd(dba)₂] (460 mg, 0.80 mmol). The mixture was stirred

for 1 h at room temperature and a small amount of palladium

black was removed by cannula filtration. n-Butyltin trichloride

(546 mg, 1.6 mmol, 2 equiv) was added slowly to the orange–

brown supernatant to give a red solution. The solvent was re-

moved in vacuo and the oily residue was triturated and washed

with hexane (3ꢂ10 mL). A white precipitate was formed after the

addition of toluene (5 mL), and filtration followed by washing with

toluene (3ꢂ5 mL) gave trans-[PdCl{(b)₂(SnClnBu)}][SnCl₄nBu] (4b)

7.2 Hz, 2H, H₉), 8.01 (t, J_HH=5.7 Hz, 2H, H₁₀), 7.88–7.84 (m, 12H, H₂,

H₄, H₆), 7.74–7.68 (m, 6H, H₅, H₈), 1.61 (s, ²J_HSn=52 Hz, 3H,

SnClCH₃), 1.42 ppm (s, ²J_HSn=116 Hz, 3H, SnCl₄CH₃). ¹³C{¹H} NMR

1

(100.54 MHz, CD₂Cl₂): d=150.2 (t, ³J_CP=9 Hz, C₁₁), 147.9 (t, J_CP

=

2

32 Hz, C₁), 142.8 (s, C₉), 138.2 (t, J_CP=7 Hz, C₆), 132.8–131.7 (m, C₃,

3

C₈), 131.4–131.3 (m, C₂), 131.0 (t, J_CP=5 Hz, C₅), 130.2–130.1 (m, C₄,

C₁₀), 129.0 (t, ¹J_CP=26 Hz, C₇), 124.1 (q, ¹J_CF=273, CF₄), 24.2 (s,

¹J_CSn=930 Hz, SnCl₄CH₃), 16.6 ppm (s, ¹J_CSn=420 Hz, SnClCH₃).

2

³¹P{¹H} NMR (161.85 MHz, CD₂Cl₂): d=63.0 (s, J_PSn=75 Hz). ¹⁹F{¹H}

NMR (376.15 MHz, CD₂Cl₂): d=ꢀ63.2 ppm (s). ¹¹⁹Sn{¹H} NMR

(149.07 MHz, CD₂Cl₂): d=56.0 (broad, w_1/2=280 Hz, SnClCH₃),

ꢀ243.6 ppm (broad, w_1/2=646 Hz, SnCl₄CH₃). HRMS (ESI): exact

mass (monoisotopic) calcd for C₃₉H₂₇Cl₂F₁₂N₂P₂PdSn: 1108.8894;

found: 1108.8903.

(718 mg, 0.49 mmol, 61% yield). H NMR (399.80 MHz, CD₂Cl₂): d=

9.20 (d, J_HH=5.0 Hz, 2H, H₁₁), 8.33 (t, J_HH=7.5 Hz, 2H, H₉), 8.07 (t,

1

J

_HH=6.1 Hz, 2H, H₁₀), 7.91–7.89 (m, 4H, H₂), 7.86–7.80 (m, 12H, H₄,

H₆), 7.77–7.72 (m, 6H, H₅, H₈), 2.17 (t, _HH=7.2 Hz, 2H,

J

Cl₄SnCH₂CH₂CH₂CH₃), 2.12 (t, J_HH=7.9 Hz, 2H, ClSnCH₂CH₂CH₂CH₃),

1.86–1.78 (m, 2H, Cl₄SnCH₂CH₂CH₂CH₃), 1.47–1.38 (m, 2H,

ClSnCH₂CH₂CH₂CH₃), 1.08–0.96 (m, 4H, Cl₄SnCH₂CH₂CH₂CH₃,

ClSnCH₂CH₂CH₂CH₃), 0.92 (t, J_HH=7.3 Hz, 3H, Cl₄SnCH₂CH₂CH₂CH₃),

trans-[PdCl{(c)₂(SnClMe)}][SnCl₄Me] (3c): Ligand

c

(211 mg,

0.791 mmol, 2.5 equiv) in toluene (5 mL) was added to a Schlenk

flask containing [Pd(dba)₂] (182 mg, 0.316 mmol). The mixture was

stirred for 1 h and a small amount of palladium black was removed

by cannula filtration. A solution of methyltin trichloride (167 mg,

0.696 mmol, 2.2 equiv) in toluene (5 mL) was added slowly to the

orange–brown solution to give a yellow solution with an orange,

oily residue. After one hour the solvent was removed in vacuo and

the residue was washed with toluene (4ꢂ5 mL). 5 mL of toluene

was then added and the mixture was stirred for 18 h to give

[PdCl{(c)₂(SnClMe)}][SnCl₄Me] 3c (327 mg, 0.292 mmol, 92% yield)

as a yellow powder after filtration and washing with toluene (4ꢂ

0.50 ppm (t, J_HH=6.8 Hz, 3H, ClSnCH₂CH₂CH₂CH₃). ¹³C {¹H} NMR

1

(100.54 MHz, CD₂Cl₂): d=150.7 (t, ³J_CP=9 Hz, C₁₁), 148.0 (t, J_CP

=

33 Hz, C₇), 143.1 (s, C₉), 138.1 (broad, C₆), 132.8–131.7 (m, C₃, C₈),

1

131.4–131.3 (m, C₂, C₅), 130.4–130.2 (m, C₄, C₁₀), 128.7 (t, J_CP

=

26 Hz, C₁), 124.1 (q, ¹J_CF=273, CF₃), 45.2 (s, Cl₄SnCH₂CH₂CH₂CH₃),

34.3 (s, ClSnCH₂CH₂CH₂CH₃), 28.8 (s, ClSnCH₂CH₂CH₂CH₃), 28.3 (s,

Cl₄SnCH₂CH₂CH₂CH₃), 27.2 (s, ClSnCH₂CH₂CH₂CH₃), 26.2 (s,

Cl₄SnCH₂CH₂CH₂CH₃), 14.2 (s, Cl₄SnCH₂CH₂CH₂CH₃), 13.9 ppm (s,

ClSnCH₂CH₂CH₂CH₃). ³¹P{¹H} NMR (161.85 MHz, CD₂Cl₂): d=

61.9 ppm (s, J_PSn=29 Hz). ¹⁹F{¹H} NMR (376.15 MHz, CD₂Cl₂): d=

ꢀ63.3 ppm (s). ¹¹⁹Sn{¹H} NMR (149.07 MHz, CD₂Cl₂): 79.9 (broad,

w_1/2=280 Hz, SnClnBu), ꢀ246.4 (broad, w_1/2=730 Hz, SnCl₄nBu).

1

5 mL). H NMR (399.80 MHz, CD₂Cl₂): d=7.67–7.61 (m, 8H, H₂, H₆),

2

7.56–7.51 (m, 12H, H₃, H₄, H₅), 3.23 (s, 6H, N-CH₃), 1.54 (s, J_HSn

=

117 Hz, 3H, SnCl₄CH₃), 1.30 ppm (s, ²J_HSn=57 Hz, 3H, SnClCH₃).

¹³C{¹H} NMR (100.54 MHz, CD₂Cl₂): d=139 (broad, C₇), 133.8 (t,

HRMS

(ESI):

exact

mass

(monoisotopic)

calcd

for

C₄₂H₃₃Cl₂F₁₂N₂P₂PdSn: 1150.9365; found: 1150.9353.

3

²J_CP=7 Hz, C₂, C₆), 133.3 (s, C₄, C₉), 130.5 (t, J_CP=6 Hz, C₃, C₅), 128.2

2

1

(t, J_CP=8 Hz, C₈), 125.7 (t, J_CP=27 Hz, C₁), 37.1 (s, N-CH₃), 21.9 (s,

SnCl₄CH₃), 12.3 ppm (s, SnClCH₃). ³¹P{¹H} NMR (161.85 MHz, CD₂Cl₂):

d=31.2 ppm (s, ²J_PSn=97 Hz). ¹¹⁹Sn{¹H} NMR (149.07 MHz, CD₂Cl₂):

d=ꢀ143.4 (broad, w_1/2=447 Hz, SnClCH₃), ꢀ254.9 ppm (broad,

w_1/2=193 Hz, SnCl₄CH₃). HRMS (ESI): exact mass (monoisotopic)

calcd for C₃₃H₃₃Cl₂N₄P₂PdSn: 842.9615; found: 842.9517.

trans-[PdCl{(c)₂(SnClnBu)}][SnCl₄nBu] (4c): Ligand

c

(115 mg,

0.43 mmol, 2.5 equiv) in toluene (5 mL) was added to a Schlenk

flask containing [Pd(dba)₂] (102 mg, 0.18 mmol). The mixture was

stirred at room temperature for one hour and a small amount of

palladium black was removed by cannula filtration. n-Butyltin tri-

chloride (101 mg, 0.36 mmol, 2 equiv) was added slowly to the

orange–brown solution. After one hour the solvent was removed

in vacuo and the residue was washed with diethyl ether (3ꢂ

10 mL) to give trans-[PdCl{(c)₂(SnClnBu)}][SnCl₄nBu] (4c) (182 mg,

0.15 mmol, 84% yield) as a yellow powder. ¹H NMR (399.80 MHz,

CD₂Cl₂): d=7.66–7.61 (m, 12H, H₂, H₆, H₈, H₉), 7.54–7.53 (m, 12H,

trans-[PdCl{(d)₂(SnClMe)}][SnCl₄Me] (3d): Ligand

d

(1.07 g,

2.66 mmol, 2.5 equiv) in toluene (5 mL) was added to a Schlenk

flask containing [Pd(dba)₂] (611 mg, 1.06 mmol). The mixture was

stirred for 1 h and a small amount of palladium black was removed

by cannula filtration. A solution of methyltin trichloride (594 mg,

2.47 mmol, 2.25 equiv) in toluene (5 mL) was added slowly to the

orange–brown solution to give a red solution with a light yellow

precipitate. After one hour the solution was concentrated in vacuo

and washing with hexane (3ꢂ5 mL) gave trans-[PdCl{(d)₂(SnClMe)}]

[SnCl₄Me] (3d) (1.24 g, 0.891 mmol, 81% yield) as a yellow powder.

¹H NMR (399.80 MHz, CD₂Cl₂): d=7.98–7.95 (m, 4H, H₂), 7.91–7.83

(m, 8H, H₄, H₆), 7.74 (t, J_HH=7.6 Hz, 4H, H₅), 7.60 (s, 4H, H₈, H₉),

H₃, H₄, H₅), 3.24 (s, 6H, N-CH₃), 2.18 (t,

J_HH=7.4 Hz, 2H,

Cl₄SnCH₂CH₂CH₂CH₃), 1.96 (t, J_HH=7.7 Hz, 2H, ClSnCH₂CH₂CH₂CH₃),

1.92–1.84 (m, 2H, Cl₄SnCH₂CH₂CH₂CH₃), 1.51–1.38 (m, 4H,

ClSnCH₂CH₂CH₂CH₃, Cl₄SnCH₂CH₂CH₂CH₃), 1.18–1.09 (m, 2H,

ClSnCH₂CH₂CH₂CH₃), 0.94 (t, J_HH=7.3 Hz, 3H, Cl₄SnCH₂CH₂CH₂CH₃),

0.65 ppm (t, J_HH=7.2 Hz, 3H, ClSnCH₂CH₂CH₂CH₃). ¹³C{¹H} NMR

2

3.31 (s, 6H, N-CH₃), 1.52 (s, J_HSn=62 Hz, 3H, SnClCH₃), 1.49 ppm (s,

(100.54 MHz, CD₂Cl₂): d=139.5 (t, ¹J_CP=34 Hz, C₇), 133.7 (t, J_CP

=

²J_HSn=116 Hz, 3H, SnCl₄CH₃). ¹³C{¹H} NMR (100.54 MHz, CD₂Cl₂): d=

7 Hz, C₂, C₆), 133.3 (broad, C₄, C₉), 130.5 (t, J_CP=6 Hz, C₃, C₅), 128.5

(t, ³J_CP=8 Hz, C₈), 125.9 (t, ¹J_CP=26 Hz, C₁), 45.4 (s,

Cl₄SnCH₂CH₂CH₂CH₃), 37.1 (s, N-CH₃), 32.7 (s, ClSnCH₂CH₂CH₂CH₃),

29.1 (s, ClSnCH₂CH₂CH₂CH₃), 28.4 (s, Cl₄SnCH₂CH₂CH₂CH₃), 27.4 (s,

ClSnCH₂CH₂CH₂CH₃), 26.3 (s, Cl₄SnCH₂CH₂CH₂CH₃), 14.3 (s,

Cl₄SnCH₂CH₂CH₂CH₃), 14.1 ppm (s, ClSnCH₂CH₂CH₂CH₃). ³¹P{¹H} NMR

(161.85 MHz, CD₂Cl₂): d=30.6 ppm (s, J_PPs=87 Hz). ¹¹⁹Sn{¹H} NMR

(149.07 MHz, CD₂Cl₂): d=ꢀ121.1 (broad, w_1/2=173 Hz, SnClnBu),

ꢀ248.1 ppm (broad, w_1/2=745 Hz, SnCl₄nBu). HRMS (ESI): exact

mass (monoisotopic) calcd for C₃₆H₃₉Cl₂N₄P₂PdSn: 885.0085; found:

885.0146.

3

1

2

137.3 (t, J_CP=35 Hz, C₇), 137.1 (t, J_CP=6 Hz, C₆), 134.1 (s, C₉), 132.7

2

3

(qt, J_CF=33 Hz, J_CP=6 Hz, C₃), 131.5 (t, J_CP=5 Hz, C₅), 130.6–130.4

(m, C₂, C₄), 129.1 (t, J_CP=8 Hz, C₈), 126.8 (t, J_CP=27 Hz, C₁), 124.1

(q, J_CF=273 Hz, CF₃), 37.4 (s, N-CH₃), 24.4 (s, SnCl₄CH₃), 14.0 ppm

2

1

(s, ¹J_CSn=510 Hz, SnClCH₃). ³¹P{¹H} NMR (161.85 MHz, CD₂Cl₂): d=

30.6 ppm (s, ²J_PSn=168 Hz). ¹⁹F{¹H} NMR (376.15 MHz, CD₂Cl₂): d=

ꢀ63.4 ppm (s). ¹¹⁹Sn{¹H} NMR (149.07 MHz, CD₂Cl₂): d=ꢀ164.9

(broad, w_1/2=1000 Hz, SnClCH₃), ꢀ247.4 ppm (broad, w_1/2=350 Hz,

SnCl₄CH₃). HRMS (ESI): exact mass (monoisotopic) calcd for

C₃₇H₂₉Cl₂F₁₂N₄P₂PdSn: 1114.9111; found: 1114.9170.

Chem. Eur. J. 2015, 21, 1765 – 1779

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ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Full Paper

trans-[PdCl{(d)₂(SnClnBu)}][SnCl₄nBu] (4d): Ligand

d

(1.15 g,

trans-[PtCl{(b)₂(SnClMe)}][SnCl₄Me] (9b): Ligand

b

(631 mg,

2.85 mmol, 2.5 equiv) in toluene (10 mL) was added to a Schlenk

flask containing [Pd(dba)₂] (655 mg, 1.10 mmol). The mixture was

stirred for one hour at room temperature and a small amount of

palladium black was removed by cannula filtration. n-Butyltin tri-

chloride (621 mg, 2.20 mmol, 2 equiv) was added slowly to the

orange–brown solution to give a yellow–green solution with

a yellow precipitate. After 1 h the reaction mixture was concentrat-

ed in vacuo. After washing with toluene (4ꢂ10 mL) trans-

[PdCl{(d)₂(SnClnBu)}][SnCl₄nBu] (4d) (1.270 mg, 0.86 mmol, 78%

1.58 mmol, 2.5 equiv) in toluene (10 mL) was added to a Schlenk

flask containing [Pt(dba)₂] (425 mg, 0.64 mmol). The mixture was

stirred for 1.5 h and a small amount of platinum black was re-

moved by cannula filtration. A solution of methyltin trichloride

(338 mg, 1.41 mmol, 2.2 equiv) was added dropwise to the yellow–

red solution, resulting in a greyish suspension. The reaction mix-

ture was then filtered, and the residue washed with hexane (3ꢂ

15 mL) and diethyl ether (3ꢂ15 mL), yielding the product

[PtCl{(b)₂(SnClMe)}][SnCl₄Me] 9b as a grey solid (43%, 398 mg,

0.28 mmol). ¹H NMR (399.80 MHz, CD₂Cl₂): d=9.17 (d, J_HH=5 Hz,

2H, H₁₁), 8.25 (t, J_HH=8 Hz, 2H, H₁₀), 8.02 (t, J_HH=6 Hz, 2H, H₉),

7.89–7.70 (m, 18H, H₂, H₄, H₅, H₆, H₈), 1.46 (s, ²J_HSn=116 Hz, 3H,

SnCl₄Me), 1.40 ppm (s, ²J_HSn=54 Hz, 3H, SnClMe). ¹³C{¹H} NMR

1

yield) was obtained as a light yellow powder. H NMR (399.80 MHz,

CD₂Cl₂): d=7.91–7.94 (m, 8H, H₂, H₄), 7.83–7.75 (m, 8H, H₅, H₆),

7.69 (s, 2H, H₉), 7.62 (s, 2H, H₈), 3.26 (s, 6H, N-CH₃), 2.16 (t, J_HH

=

2

7.5 Hz, J_HSn=107 Hz, 2H, Cl₄SnCH₂CH₂CH₂CH₃), 2.07 (t, J_HH=7.7 Hz,

²J_HSn=64 Hz, 2H, ClSnCH₂CH₂CH₂CH₃), 1.89–1.82 (m, 2H,

Cl₄SnCH₂CH₂CH₂CH₃), 1.50–1.41 (m, 4H, Cl₄SnCH₂CH₂CH₂CH₃,

ClSnCH₂CH₂CH₂CH₃), 1.22–1.12 (m, 2H, ClSnCH₂CH₂CH₂CH₃), 0.93 (t,

(100.54 MHz, CD₂Cl₂): d=149.7 (t, ³J_CP=8 Hz, C₁₁), 146.0 (t, J_CP

=

2

37 Hz, C₇), 142.4 (s, C₁₀), 137.2 (t, ²J_CP=6 Hz, C₆), 131.5 (qt, J_CF

45 Hz, ³J_CP=6 Hz, C₃), 131.4 (q, ³J_CF=5 Hz, C₄), 130.7 (broad, C₂),

130.4 (t, J_CP=5 Hz, C₈), 129.7–129.6 (broad, C₅, C₉), 127.2 (t, J_CP

2

J

_HH=7.3 Hz, 3H, Cl₄SnCH₂CH₂CH₂CH₃), 0.66 ppm (t, J_HH=7.3 Hz, 3H,

=

ClSnCH₂CH₂CH₂CH₃). ¹³C{¹H} NMR (100.54 MHz, CD₂Cl₂): d=137.3 (t,

¹J_CP=35 Hz, C₇), 136.8 (t, ²J_CP=6 Hz, C₆), 134.4 (s, C₉), 132.8 (qt,

30 Hz, C₁), 123.3 (q, J_CF=272 Hz, CF₃), 23.6 (s, J_CSn=915 Hz,

2

SnCl₄Me), 12.8 ppm (s, J_CSn=500 Hz, J_CPt=131 Hz, SnClMe). ¹⁹F{¹H}

NMR (376.4 MHz, CD₂Cl₂): d=ꢀ63.5 ppm (s). ³¹P{¹H} NMR

(161.85 MHz, CD₂Cl₂): d=59.6 ppm (s, J_PPt=2780 Hz, ²J_PSn=87 Hz).

¹¹⁹Sn{¹H} NMR (149.07 MHz, CD₂Cl₂): d=ꢀ21.4 (t, J_PtSn=18900,

²J_SnP=85.3 Hz, SnMeCl), ꢀ256.5 ppm (s, SnCl₄Me). ¹⁹⁵Pt{¹H} NMR

²J_CF=33 Hz, J_CP=6 Hz, C₃), 131.6 (t, J_CP=5 Hz, C₅), 130.5–130.4 (m,

C₂, C₄), 129.4 (t, J_CP=8 Hz, C₈), 126.8 (t, J_CP=27 Hz, C₁), 124.0 (q,

¹J_CF=273 Hz, CF₃), 45.3 (s, J_CSn=900 Hz, Cl₄SnCH₂CH₂CH₂CH₃), 37.5

3

2

1

(s, N-CH₃), 33.0 (s, ¹J_CSn=475 Hz, ClSnCH₂CH₂CH₂CH₃), 29.2 (s,

ClSnCH₂CH₂CH₂CH₃), 28.4 (s, Cl₄SnCH₂CH₂CH₂CH₃), 27.4 (s,

ClSnCH₂CH₂CH₂CH₃), 26.2 (s, Cl₄SnCH₂CH₂CH₂CH₃), 14.2 (s,

Cl₄SnCH₂CH₂CH₂CH₃), 13.9 ppm (s, ClSnCH₂CH₂CH₂CH₃). ³¹P{¹H} NMR

(161.85 MHz, CD₂Cl₂): d=30.2 ppm (s, ²J_PSn=86 Hz). ¹⁹F{¹H} NMR

(376.15 MHz, CD₂Cl₂): d=ꢀ63.4 ppm (s). ¹¹⁹Sn{¹H} NMR

(149.07 MHz, CD₂Cl₂): d=ꢀ128.1 (broad, w_1/2=420 Hz, SnClnBu),

ꢀ251.8 ppm (broad, w_1/2=130 Hz, SnCl₄nBu). HRMS (ESI): exact

mass (monoisotopic) calcd for C₄₀H₃₅F₁₂Cl₂N₄P₂PdSn: 1157.9583;

found: 1156.9606.

(85.94 MHz, CD₂Cl₂): d=ꢀ5198.6 ppm (t, J_PtP=2805 Hz, J_Pt117Sn

=

18072 Hz, J_Pt119Sn=18905 Hz). HRMS (ESI): exact mass (monoisotop-

ic) calcd for C₃₉H₂₇N₂F₁₂P₂Cl₂SnPt: 1196.949; found: 1196.946.

trans-[PtCl{(c)₂(SnClMe)}][SnCl₄Me] (9c): Ligand

c

(308 mg,

1.156 mmol, 2.6 equiv) in toluene (10 mL) was added to a Schlenk

flask containing [Pt(dba)₂] (298 mg, 0.449 mmol). The mixture was

stirred for 1.5 h and a small amount of platinum black was re-

moved by cannula filtration. A solution of methyltin trichloride

(254 mg, 1.06 mmol, 2.3 equiv) in toluene (5 mL) was added drop-

wise to the yellow–red solution, resulting in a brown oily suspen-

sion. The reaction mixture was then stirred overnight, resulting in

a grey suspension from which the solvent was decanted. The re-

sulting grey solid was washed with diethyl ether (3ꢂ15 mL),

hexane (3ꢂ15 mL), and toluene (3ꢂ15 mL), yielding the product

[PtCl{(c)₂(SnClMe)}][SnCl₄Me] (9c) as an off-white solid (58%,

317 mg, 0.26 mmol). ¹H NMR (399.80 MHz, CD₂Cl₂): d=7.67–7.40

(m, 24H, all H except methyl groups), 3.21 (s, 6H, N-CH₃), 1.52 (s,

²J_HSn=118 Hz, 3H, SnCl₄Me), 1.20 ppm (s, ²J_HSn=59 Hz, 3H,

SnClMe). ¹³C{¹H} NMR (100.54 MHz, CD₂Cl₂): d=136.8 (t, J_CP=40 Hz,

trans-[PtCl{(a)₂(SnClMe)}][SnCl₄Me] (9a): Ligand

a

(524 mg,

1.99 mmol, 2.5 equiv) in toluene (10 mL) was added to a Schlenk

flask containing [Pt(dba)₂] (520 mg, 0.783 mmol). The mixture was

stirred for 1.5 h and a small amount of platinum black was re-

moved by cannula filtration. A solution of methyltin trichloride

(424 mg, 1.76 mmol, 2.3 equiv) in toluene (5 mL) was added drop-

wise to the yellow–red solution, resulting in a brown oily suspen-

sion. The reaction mixture was then decanted, and the residue

stirred overnight with hexane (15 mL). The resulting yellow–brown

solid was washed with diethyl ether (3ꢂ15 mL) and toluene (3ꢂ

15 mL), yielding the product [PtCl{(a)₂(SnClMe)}][SnCl₄Me] (9a) as

a white solid (88%, 832 mg, 0.69 mmol). Slow diffusion of diethyl

ether into a concentrated dichloromethane solution resulted in col-

ourless single crystals suitable for X-ray analysis. ¹H NMR

2

C₇), 133.1 (t, J_CP=7.0 Hz, C₂, C₆), 132.7 (s, C₄) 132.6 (s, C₈), 129.6 (t,

3

³J_CP=5.8 Hz, C₃, C₅), 127.1 (t, J_CP=7.2 Hz, C₉), 124.3 (t, J_CP=31 Hz,

C₁), 36.2 (s, N-CH₃), 23.8 (s, SnCl₄Me), 9.1 ppm (s, J_CSn=500 Hz,

SnClMe). ³¹P{¹H} NMR (161.85 MHz, CD₂Cl₂): d=27.1 ppm (s, J_PPt

=

2803 Hz, ²J_PSn=89 Hz). ¹¹⁹Sn{¹H} NMR (149.07 MHz, CD₂Cl₂): d=

ꢀ219.7 (t, J_SnPt=19819 Hz, ²J_SnP=89 Hz, SnClMe), ꢀ259.1 ppm (s,

SnCl₄Me). ¹⁹⁵Pt{¹H} NMR (85.94 MHz, CD₂Cl₂): d=ꢀ5025.0 ppm (t,

(399.80 MHz, CD₂Cl₂): d=9.11 (d, J_HH=4.8 Hz, 2H, H₁₁), 8.12 (t, J_HH

=

8 Hz, 2H, H₁₀), 7.89 (t, J_HH=6.4 Hz, 2H, H₉), 7.69 (d, J_HH=7.6 Hz, 2H,

J

_PtP=2803 Hz, J_Pt117Sn=18964 Hz, J_Pt119Sn=19847 Hz). HRMS (ESI):

2

H₈), 7.59–7.50 (m, 20H, H_2,H₃, H₄, H₅, H₆), 1.54 (s, J_HSn=117 Hz, 3H,

exact mass (monoisotopic) calcd for C₃₃H₃₃N₄P₂Cl₂SnPt: 931.0215;

found: 931.0062.

SnCl₄CH₃), 1.27 ppm (s, ²J_HSn=40 Hz, 3H, SnClMe). ¹³C{¹H} NMR

(100.54 MHz, CD₂Cl₂): d=149.0 (t, ³J_CP=8 Hz, C₁₁), 148.4 (t, J_CP

=

36 Hz, C₇), 141.9 (s, C₁₀), 134.0 (t, ²J_CP=7 Hz, C₂, C₆), 132.5 (s, C₄),

131.2 (t, ²J_CP=7 Hz, C₈), 129.4 (t, ³J_CP=6 Hz, C₃, C₅), 128.2 (s, C₉),

trans-[PtCl{(a)₂(SnClnBu)}][SnCl₄nBu] (10a): Ligand a (5151 mg,

1.96 mmol, 2.6 equiv) in toluene (10 mL) was added to a Schlenk

flask containing [Pt(dba)₂] (499 mg, 0.75 mmol). The mixture was

stirred for 1.5 h and a small amount of platinum black was re-

moved by cannula filtration. n-Butyltin trichloride (285 mL,

1.71 mmol, 2.3 equiv) was added dropwise to the yellow–red solu-

tion, after which the reaction mixture was stirred, overnight, result-

ing in a yellow–brown precipitate. The reaction mixture was then

filtered, and the residue washed with hexane (3ꢂ15 mL) and di-

ethyl ether (3ꢂ15 mL), yielding the product [PtCl{(a)₂(SnClnBu)}]

1

126.5 (t, J_CP=30 Hz, C₁), 23.9 (s, J_CSn=950 Hz, SnCl₄CH₃), 11.5 ppm

1

2

(s, J_CSn=530 Hz, J_CPt=139 Hz SnClCH₃). ³¹P{¹H} NMR (161.85 MHz,

CD₂Cl₂): d=58.5 ppm (s, ¹J_PPt=2727 Hz, ²J_PSn=87 Hz, ¹J_PC=30 Hz).

¹¹⁹Sn{¹H} NMR (149.07 MHz, CD₂Cl₂): d=ꢀ5.0 (t, ¹J_SnPt=19201 Hz,

²J_SnP=94 Hz, SnClMe), ꢀ254.1 ppm (s, SnCl₄Me). ¹⁹⁵Pt{¹H} NMR

1

(85.94 MHz, CD₂Cl₂): d=ꢀ5165.0 ppm (t, ¹J_PtP=2695 Hz, J_Pt117Sn

=

18404 Hz, ¹J_Pt119Sn=18884 Hz). HRMS (ESI): exact mass (monoiso-

topic) calcd for C₃₅H₃₁N₂P₂PtSnCl₂: 924.9998; found: 924.9961.

Chem. Eur. J. 2015, 21, 1765 – 1779

www.chemeurj.org

1775

ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Full Paper

[SnCl₄nBu] 10a as

a

yellow–white solid (66%, 637 mg,

lution, after which the reaction mixture was stirred overnight, re-

sulting in a light yellow precipitate. The reaction mixture was then

filtered, and the residue washed with hexane (3ꢂ15 mL), diethyl

ether (3ꢂ15 mL), and toluene (3ꢂ15 mL), yielding the product

[PtCl{(c)₂(SnClnBu)}][SnCl₄nBu] (10c) as a white solid (27%, 108 mg,

0.083 mmol). Slow diffusion of diethyl ether into a concentrated di-

chloromethane solution resulted in single crystals suitable for X-ray

analysis. ¹H NMR (399.80 MHz, CD₂Cl₂): d=7.77 (s, 2H, H₉), 7.63–

7.51 (m, 22H, H₂, H₃, H₄, H₅, H₆, H₈,), 3.23 (s, 6H, N-CH₃), 2.15 (t,

0.495 mmol). ¹H NMR (399.80 MHz, CD₂Cl₂): d=9.13 (d, J_HH=6 Hz,

2H, H₁₁), 8.80 (t, J_HH=7 Hz, 2H, H₁₀), 7.93 (t, J_HH=6 Hz, 2H, H₉), 7.71

(d, J_HH=8 Hz, 2H, H₈), 7.60 (d, J_HH=6 Hz, 8H, H₂, H₆), 7.54–7.53 (m,

16H, H₃, H₄, H₅), 2.16 (t,

SnCl₄CH₂CH₂CH₂CH₃), 1.94 (t,

J

_HH=8 Hz, ²J_HSn=108 Hz, 2H,

J

_HH=8 Hz, ²J_HSn=58 Hz, 2H,

SnClCH₂CH₂CH₂CH₃), 1.87 (m, 2H, SnCl₄CH₂CH₂CH₂CH₃), 1.45 (m, 2H,

SnClCH₂CH₂CH₂CH₃), 0.99–0.85 (m, 7H, SnCl₄CH₂CH₂CH₂CH₃,

SnClCH₂CH₂CH₂CH₃, SnCl₄CH₂CH₂CH₂CH₃), 0.41 ppm (t, J_HH=7 Hz,

3H, SnClCH₂CH₂CH₂CH₃). ¹³C{¹H} NMR (100.54 MHz, CD₂Cl₂): d=

J

_HH=8 Hz, 2H, SnCl₄CH₂CH₂CH₂CH₃), 1.89 (t,

SnClCH₂CH₂CH₂CH₃), 1.84 (m, 2H, SnCl₄CH₂CH₂CH₂CH₃), 1.47–1.36

(m, 4H, SnClCH₂CH₂CH₂CH₃, SnCl₄CH₂CH₂CH₂CH₃), 1.11 (m, J_HH

J_HH=8 Hz, 2H,

3

149.3 (t, J_CP=9 Hz, C₁₁), 148.8 (t, J_CP=36 Hz, C₇) 141.9 (s, C₁₀), 134.0

2

(t, J_CP=7 Hz, C₂, C₆), 132.5 (s, C₄), 131.4 (t, J_CP=7 Hz, C₈), 129.3 (t,

=

³J_CP=5 Hz, C₃, C₅), 128.9 (s, C₉), 126.5 (t, J_CP=30 Hz, C₁), 44.5 (s,

7.4 Hz, 2H, SnClCH₂CH₂CH₂CH₃), 0.92 (t,

J

_HH=7.4 Hz, 3H,

2

J

_CSn=900 Hz, SnCl₄CH₂CH₂CH₂CH₃), 31.1 (s, J_CSn=450 Hz, J_CPt

=

SnCl₄CH₂CH₂CH₂CH₃),

0.60 ppm

(t,

J

_HH=7.2 Hz,

3H,

131 Hz, SnClCH₂CH₂CH₂CH₃), 27.6 (s, SnCl₄CH₂CH₂CH₂CH₃), 27.4 (s,

SnClCH₂CH₂CH₂CH₃), 26.2 (s, SnCl₄CH₂CH₂CH₂CH₃), 25.4 (s,

SnClCH₂CH₂CH₂CH₃), 13.5 (s, SnCl₄CH₂CH₂CH₂CH₃), 13.1 ppm (s,

SnClCH₂CH₂CH₂CH₃). ³¹P{¹H} NMR (161.85 MHz, CD₂Cl₂): d=

SnCl₄CH₂CH₂CH₂CH₃). ¹³C{¹H} NMR (100.54 MHz, CD₂Cl₂): d=137.1 (t,

2

J

_CP=40 Hz, C₇), 133.1 (t, J_CP=6.5 Hz, C₂, C₆), 132.7 (s, C₈), 132.6 (s,

3

C₄), 129.6 (t, J_CP=5.7 Hz, C₃, C₅), 127.3 (t, J_CP=7.2 Hz, C₉), 124.5 (t,

_CP=30.8 Hz, C₁), 44.5 (s, SnCl₄CH₂CH₂CH₂CH₃), 36.4 (s, N-CH₃), 29.3

J

58.1 ppm (s, J_PPt=2702 Hz, J_PSn=85 Hz, J_PC=30 Hz). ¹¹⁹Sn{¹H} NMR

(s, J_CPt=114 Hz, SnClCH₂CH₂CH₂CH₃), 28.0 (s, SnCl₄CH₂CH₂CH₂CH₃),

27.6 (s, SnClCH₂CH₂CH₂CH₃), 26.3 (s, SnCl₄CH₂CH₂CH₂CH₃), 25.4 (s,

SnClCH₂CH₂CH₂CH₃), 13.4 (s, SnCl₄CH₂CH₂CH₂CH₃), 13.3 ppm (s,

SnClCH₂CH₂CH₂CH₃). ³¹P{¹H} NMR (161.85 MHz, CD₂Cl₂): d=

2

(149.07 MHz, CD₂Cl₂): d=ꢀ1.35 (t, J_SnPt=17732 Hz, ²J_SnP=84 Hz,

SnnBuCl), ꢀ258.2 ppm (s, SnnBuCl₄). ¹⁹⁵Pt{¹H} NMR (85.94 MHz,

CD₂Cl₂): d=ꢀ5166.7 ppm (t,

J_PtP=2703 Hz, J_Pt117Sn=16937 Hz,

J

_Pt119Sn=17722 Hz). HRMS (ESI): exact mass (monoisotopic) calcdfor

27.0 ppm (s,

J

_PPt=2838 Hz, ²J_PSn=81 Hz). ¹¹⁹Sn{¹H} NMR

C₃₈H₃₇N₂P₂Cl₂SnPt: 967.0469; found: 967.0389.

(149.07 MHz, CD₂Cl₂): d=ꢀ216.9 (t, J_SnPt=18694 Hz, ²J_SnP=85 Hz,

SnnBuCl), ꢀ259.1 ppm (s, SnnBuCl₄). ¹⁹⁵Pt{¹H} NMR (85.94 MHz,

CD₂Cl₂): d=ꢀ5025.3 ppm (t, J_PtP=2824 Hz). HRMS (ESI): exact mass

(monoisotopic) calcd for C₃₆H₃₉N₄P₂Cl₂SnPt: 973.0741; found:

973.0686.

trans-[PtCl{(b)₂(SnClnBu)}][SnCl₄nBu] (10b): Ligand

b (397 mg,

0.994 mmol, 3.2 equiv) in toluene (10 mL) was added to a Schlenk

flask containing [Pt(dba)₂] (202 mg, 0.305 mmol). The mixture was

stirred for 1.5 h and a small amount of platinum black was re-

moved by cannula filtration. n-Butyltin trichloride (120 mL,

0.718 mmol, 2.3 equiv) was added dropwise to the yellow–red so-

lution, after which the reaction mixture was stirred for two hours.

The reaction mixture was then concentrated in vacuo, and the

black oily residue was washed with hexane (3ꢂ15 mL) and diethyl

ether (3ꢂ15 mL), yielding the product [PtCl{(b)₂(SnClnBu)}]

[SnCl₄nBu] (10b) as a white solid (30%, 139 mg, 0.092 mmol).

¹H NMR (399.80 MHz, CD₂Cl₂): d=9.20 (d, J_HH=5 Hz, 2H, H₁₁), 8.30

(t, J_HH=8 Hz, 2H, H₁₀), 8.05 (t, J_HH=6 Hz, 2H, H₉), 7.90–7.74 (m,

18H, H₂, H₄, H₅, H₆, H₈), 2.15 (t, J_HH=8 Hz, 2H, SnCl₄CH₂CH₂CH₂CH₃),

X-ray crystal structure determinations

Reflections were measured on a Bruker Kappa ApexII diffractom-

eter with sealed tube and Triumph monochromator (l=

0.71073 ꢁ). Software packages used for the intensity integration

were Eval15^[57](compounds 2’d, 3b, 5’a, 9a, 10’c) and Saint^[58](3a,

4c). Absorption correction was performed with SADABS and TWI-

NABS.^[59]The structures were solved with direct methods using

SHELXS-97^[60](2’d, 3a, 3b, 4c, 5’a, 9a) or automated Patterson

methods using DIRDIF2008^[61](10’c). Least-squares refinement was

performed with SHELXL-97^[60]against F²of all reflections. Non-

hydrogen atoms were refined freely with anisotropic displacement

parameters. Hydrogen atoms were calculated positions (2’d, 3b,

4c, 5’a, 10’c) or located in difference Fourier maps (3a, 9a). All

hydrogen atoms were refined with a riding model.

2.06 (t,

J_HH=8 Hz, 2H, SnClCH₂CH₂CH₂CH₃), 1.85 (m, 2H,

SnCl₄CH₂CH₂CH₂CH₃), 1.44 (s, J_HH=8 Hz, 2H, SnCl₄CH₂CH₂CH₂CH₃),

1.01–0.90 (m, 7H, SnClCH₂CH₂CH₂CH₃, SnClCH₂CH₂CH₂CH₃,

SnCl₄CH₂CH₂CH₂CH₃),

0.43 ppm

(t,

J

_HH=7 Hz,

3H,

SnClCH₂CH₂CH₂CH₃). ¹³C{¹H} NMR (100.54 MHz, CD₂Cl₂): d=150.0 (t,

³J_CP=8 Hz, C₁₁), 146.3 (s, C₇), 142.5 (s, C₁₀), 137.1 (t, J_CP=6 Hz, C₆),

2

CCDC 1008547 (2’d), 1008548 (3a), 1008549 (3b), 1008550 (4c),

1008551 (5’a), 1008552 (9a), and 1008553 (10’c) contain the sup-

plementary crystallographic 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.

131.5 (t, J_CP=6 Hz, C₈), 130.5 (broad, C₂, C₄), 129.8 (s, C₅), 127.2 (t,

J

_CP=30 Hz, C₁), 123.2 (q,

J_CF=273 Hz, CF₃), 44.3 (s,

SnCl₄CH₂CH₂CH₂CH₃), 30.5 (s, SnClCH₂CH₂CH₂CH₃), 27.6 (s,

SnCl₄CH₂CH₂CH₂CH₃), 27.5 (s, SnClCH₂CH₂CH₂CH₃), 26.2 (s,

SnCl₄CH₂CH₂CH₂CH₃), 25.4 (s, SnClCH₂CH₂CH₂CH₃), 13.4 (s,

SnCl₄CH₂CH₂CH₂CH₃), 12.9 ppm (s, SnCl₄CH₂CH₂CH₂CH₃). ¹⁹F{¹H}

NMR (376.4 MHz, CD₂Cl₂): d=ꢀ63.5 ppm (s). ³¹P{¹H} NMR

(161.85 MHz, CD₂Cl₂): d=59.2 ppm (s, J_PPt=2773 Hz, ²J_PSn=94 Hz).

¹¹⁹Sn{¹H} NMR (149.07 MHz, CD₂Cl₂): d=ꢀ13.8 (t, J_SnPt=17370 Hz,

²J_SnP=78 Hz, SnClnBu), ꢀ260.7 ppm (s, SnCl4nBu). ¹⁹⁵Pt{¹H} NMR

3a: Single crystals were obtained by vapour diffusion of diethyl

ether into a dichloromethane solution of 3a as their solvate

3a·CH₂Cl₂·Et₂O. The diethyl ether molecule was disordered on an

1

inversion centre and was refined with an occupancy of = . The dis-

2

placement parameters of this molecule were restrained.

(85.94 MHz, CD₂Cl₂): d=ꢀ5200.8 ppm (t, J_PtP=2796 Hz, J_Pt117Sn

=

3b: Single crystals were obtained by slow evaporation of a di-

chloromethane solution of 3b as their solvate 3b·2CH₂Cl₂. Six tri-

fluoromethyl groups were rotationally disordered and one CH₂Cl₂

solvent molecule was disordered over two positions. Restraints

were used for the distances, angles, and displacement parameters

of the disordered groups.

16602, J_Pt119Sn=17370 Hz). HRMS (ESI): exact mass (monoisotopic)

calcd for C₄₂H₃₃N₂F₁₂P₂Cl₂SnPt: 1238.996; found: 1238.998.

trans-[PtCl{(c)₂(SnClnBu)}][SnCl₄nBu] (10c): Ligand

c

(257 mg,

0.965 mmol, 3 equiv) in toluene (10 mL) was added to a Schlenk

flask containing [Pt(dba)₂] (206 mg, 0.310 mmol). The mixture was

stirred for 1.5 h and a small amount of platinum black was re-

moved by cannula filtration. n-Butyltin trichloride (130 mL,

0.779 mmol, 2.5 equiv) was added dropwise to the yellow–red so-

4c: Single crystals were obtained by slow diffusion of diethyl ether

into a dichloromethane solution of 4c. The structure contains large

voids (375 ꢁ³per unit cell) filled with disordered diethyl ether mol-

Chem. Eur. J. 2015, 21, 1765 – 1779

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ecules. Their contribution to the structure factors was secured by

back-Fourier transformation using the SQUEEZE routine of

PLATON^[62](82 electrons per unit cell).

5’a: Single crystals were obtained by layering a dichloromethane

solution of 5’a with toluene as their solvate 5a·toluene. The crystal

structure has been refined as a racemic twin with two independent

formula units in the asymmetric unit. The presence of pseudo-sym-

metry elements (82% fit) indicate the higher symmetric space

group Pbca, which is not fulfilled by the systematic extinctions.

9a: Single crystals were obtained by vapour diffusion of diethyl

ether into a dichloromethane solution of 9a. Along with the or-

dered CH₂Cl₂solvent molecules, the structure contains large voids

(452 ꢁ³per unit cell) filled with disordered diethyl ether molecules.

Their contribution to the structure factors was secured by back-

Fourier transformation using the SQUEEZE routine of PLATON^[62]

(90 electrons per unit cell).

10’c: Single crystals were obtained by vapour diffusion of diethyl

ether into a dichloromethane solution of 10c. Along with the or-

dered CH₂Cl₂solvent molecules, the structure contains large voids

(339 ꢁ³per unit cell) filled with disordered diethyl ether molecules.

Their contribution to the structure factors was secured by back-

Fourier transformation using the SQUEEZE routine of PLATON^[62]

(87 electrons per unit cell).

2’d: Single crystals were obtained by layering an acetonitrile solu-

tion of 2d (also containing 2’d) with diethyl ether. The structure

appeared to be non-merohedrally twinned with a twofold rotation

about hkl=(0,0,1) as twin operation. The twin fraction refined to

0.4006(7). This twin fraction was used to generate a de-twinned re-

flection file, which was used for the SQUEEZE routine of PLATON^[62]

to handle the severely disordered acetonitrile molecules. Solvent

accessible voids in this structure were 379 ꢁ³per unit cell and the

solvent contribution to the structure factors was 185 electrons per

unit cell. All trifluoromethyl groups were rotationally disordered.

Restraints were used for the distances, angles, and displacement

parameters of the disordered groups.

Geometry calculations and checking for higher symmetry were per-

formed with PLATON.^[62]Further details are given in Tables 4 and 5.

Acknowledgements

This work was financially supported by ARKEMA B.V. (S.W.,

E.J.D., Y.C.). The authors thank Dr. J. T. B. H. Jastrzebski for assis-

tance with the HSQC NMR measurements and H. Kleijn for ESI-

Table 4. Details of the X-ray crystal structures determinations for compounds 3a, 3b, 4c, and 9a.

3a

3b

4c

9a

formula

F.W.

crystal colour Colourless

crystal size

[mm³]

[C₃₅H₃₁Cl₂N₂P₂PdSn]

[CH₃Cl₄Sn]·CH₂Cl₂·0.5C₄H₁₀O

[C₃₉H₂₇Cl₂F₁₂N₂P₂PdSn]

[CH₃Cl₄Sn]·2CH₂Cl₂

[C₃₆H₃₉Cl₂N₄P₂PdSn]

[C₄H₉Cl₄Sn]+disordered diethyl

ether

[C₃₅H₃₁Cl₂N₂P₂PtSn]

[CH₃Cl₄Sn]·CH₂Cl₂+disordered diethyl

ether

1286.69^[a]

colourless

0.48ꢂ0.28ꢂ0.13

1235.06

1554.93

colourless

0.68ꢂ0.21ꢂ0.11

1203.24^[a]

colourless

0.34ꢂ0.32ꢂ0.18

0.35ꢂ0.25ꢂ0.04

150(2)

T [K]

150(2)

crystal system monoclinic

triclinic

monoclinic

P2₁/c (no. 14)

21.0398(6)

13.4720(4)

16.8277(7)

–

102.127(2)

–

4663.4(3)

4

1.833^[a]

0.65

¯

space group

a [ꢁ]

b [ꢁ]

c [ꢁ]

a [8]

P2₁/c (no. 14)

20.9090(17)

13.4400(11)

16.8925(13)

–

P1 (no. 2)

12.5860(7)

17.9996(12)

24.5327(10)

98.455(2)

95.697(2)

90.086(2)

5469.4(5)

4

13.2494(3)

13.5561(3)

15.7011(4)

95.8089(9)

103.4169(10)

104.4795(9)

2617.75(11)

2

b [8]

101.557(2)

–

4650.8(6)

4

1.764

0.65

g [8]

V [ꢁ³]

Z

D_calcd[gcm^ꢀ3

(sinq/l)_max

]

1.888

0.65

1.527^[a]

0.65

[ꢁ^ꢀ1

m [mm^ꢀ1

]

2.01

1.85

1.68^[a]

4.61^[a]

abs. corr.

range

analytical

0.59–0.93

analytical

0.42–0.96

multiscan

0.36–0.43

analytical

0.18–0.64

refl. mea-

sured/unique

parameters/re- 515/30

straints

70792/10480

95760/25133

1479/2065

46722/11991

500/0

58525/10687

470/0

R1/wR2

[I>2s(I)]

R1/wR2 (all

refl.)

0.0265/0.0578

0.0344/0.0849

0.0466/0.0915

0.0220/0.0539

0.0256/0.0553

0.0193/0.0435

0.0213/0.0440

0.0430/0.0657

S

1.049

ꢀ1.05/0.84

1.036

ꢀ1.34/1.61

1.042

ꢀ0.87/1.04

1.045

ꢀ1.31/1.68

1_(min/max)[eꢁ^ꢀ3

]

[a] Derived values do not contain the contribution of the disordered solvent.

Chem. Eur. J. 2015, 21, 1765 – 1779

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1777

ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

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Table 5. Details of the X-ray crystal structures determinations for compounds 2’d, 5’a, and 10’c.

2’d

5’a

10’c

formula

F.W.

crystal colour

crystal size [mm³]

T [K]

C₃₇H₂₉Cl₃F₁₂N₄P₂PdSn+disordered acetonitrile

C₄₀H₃₃Cl₃N₂P₂PdSn·C₇H₈

1027.20

yellow

0.58ꢂ0.40ꢂ0.25

150(2)

C₃₆H₃₉Cl₃N₄P₂PtSn·CH₂Cl₂+disordered solvent

1151.02^[a]

pale yellow

0.54ꢂ0.52ꢂ0.06

150(2)

1094.71^[a]

pale yellow

0.55ꢂ0.23ꢂ0.08

150(2)

crystal system

space group

a [ꢁ]

b [ꢁ]

c [ꢁ]

monoclinic

P2₁(no. 4)

15.2996(6)

19.9385(10)

15.8554(5)

–

97.658(2)

–

4793.6(3)

4

1.595^[a]

orthorhombic

P2₁2₁2₁(no. 19)

14.40393(19)

23.3573(2)

25.6608(5)

–

triclinic

˜

P1 (no. 2)

12.4043(4)

13.5396(5)

15.7985(4)

78.617(1)

67.570(2)

68.635(2)

2278.81(13)

2

a [8]

b [8]

–

g [8]

V [ꢁ³]

8633.3(2)

8

1.581

Z

D_calcd[gcm^ꢀ3

]

1.595^[a]

(sinq/l)_max[ꢁ^ꢀ1

m [mm^ꢀ1

abs. corr.

abs. corr. range

refl. measured/

unique

]

0.65

1.29

multiscan

0.67–0.75

135405/19811

0.65

]

1.21^[a]

4.01^[a]

multiscan

0.31–0.43

70118/11316

multiscan

0.27–0.43

52735/10457

parameters/restraints

R1/wR2 [I>2s(I)]

R1/wR2

1303/3673

0.0217/0.0549

0.0224/0.0553

1012/0

0.0185/0.0424

0.0192/0.0426

454/0

0.0205/0.0493

0.0226/0.0499

(all refl.)

Flack parameter^[b]

S

0.104(12)

1.032

ꢀ0.62/0.61

0.570(15)

1.106

ꢀ0.43/0.44

–

1.029

ꢀ0.82/1.43

1_(min/max)[eꢁ^ꢀ3

]

[a] Derived values do not contain the contribution of the disordered solvent. [b] See Ref. [63].

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Published online on November 25, 2014

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Article Doi

Intramolecularly stabilised group 10 metal stannyl and stannylene complexes: Multi-pathway synthesis and observation of platinum-to-tin alkyl transfer

DOI: 10.1002/chem.201404071

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