Copper(I) and silver(I) bis(trifluoromethanesulfonyl)imide and their interaction with an arene, diverse olefins, and an NTf2 --based ionic liquid

DOI: 10.1002/chem.201201740

Copper(I) and Silver(I) Bis(trifluoromethanesulfonyl)imide and Their

ꢀ

Interaction with an Arene, Diverse Olefins, and an NTf₂-Based Ionic Liquid

Marion Stricker, Benjamin Oelkers, Carl Philipp Rosenau, and Jçrg Sundermeyer*^[a]

Abstract: The chemistry of coinage

metal bis(triflyl)imides of technological

N

ethyl-3-methylimidazolium), has been

studied. Furthermore, the reaction of

1–3 towards the diolefins 1,5-cycloocta-

ACHTUNGTRENNUNG

interest, CuNTf₂and AgNTf₂, their

synthesis and complexes with excess of

comparatively weakly coordinating

G

ACHTUNGTRENNUNG

diene

(COD),

2,5-norbornadiene

(NBD) and isoprene (2-methylbuta-

1,3-diene) and towards ethylene has

been investigated. The products 4–13

of these conversions have been isolated

and fully characterized by NMR- and

IR spectroscopies, mass spectrometry,

and elemental- and XRD analyses. The

ꢀ

NTf₂as well as with ether, olefins, and

ꢀ

the arene mesitylene are described.

The existence of the solvent-free pure

phase [CuNTf₂]₁has not been evi-

denced so far. Contrary to the litera-

ture, in which the preparation of

[CuNTf₂]₁is supposed to be carried

out by reacting mesityl copper, [Cu-

potential of [Cu

(1), [Cu(Et₂O)

[AgNTf₂]₁(3) as well as of [emim][M-

(NTf₂)₂] (M=Cu 4, Ag 5) as chemi-

A

ACHTUNGTRENNUNG

A

ACHTUNGTRENNUNG

ACHTUNGTRENNUNG(Mes)]₅, and HNTf₂, we found that in

fact this reaction leads reproducibly to

the interesting copper diarene sand-

ACHTUNGTRENNUNG

Keywords: chemisorption · copper ·

ionic liquids · olefins · silver

sorbers for ethylene was studied by

NMR spectroscopy.

wich complex [CuACTHNUTRGNEUNG

(h³-MesH)₂][Cu-

Introduction

(Imⁿ)₂]

ACHUTGTNRENNUG HCATUNGTERN[NUNG CuX₂] (n=2, 6, 12; X=Cl, Br) arises from their cat-

alytic activity in oxidative methanol carbonylation^[5]and by

their use as supported ionic liquid phase (SILP) catalysts in

a continuous gas phase reaction towards dimethyl carbo-

nate.^[6]

The syntheses of the bis(trifluoromethanesulfonyl)imide

ꢀ

(also known as bis

(triflyl)imide, NTf₂) salts of the coinage

metal ions Cu⁺and Ag⁺have been reported in the

1990s.^[1,2]However, in the case of the copper(I) salt it has

not been proven by common methods (such as elemental-

or crystal structure analyses) that the solvent-free compound

really exists. Very recently, the groups of Binnemans and

Fransaer published the synthesis and solid state structure of

In contrast to copper(I) bisACHTNUTRGNE(UNG triflyl)imide, silver(I) bis-

AHCTUNGTREG(NNUN triflyl)imide has been completely characterized with the ex-

ception of its crystal structure determination.^[2,7–11]Within

the last two decades AgNTf₂has attracted a lot of interest

due to its versatility: AgNTf₂is used as catalyst for a variety

ꢀ

the ionic liquids (ILs) [Cu

CH₃CN, n=1, 2, 4; L=Im², n=2; Im²=1-ethylimidazole)

and [Ag(CH₃CN)₄]₂[Ag(NTf₂)₃] and their use in the electro-

deposition of copper and silver.^[3]The copper(I) complex

was synthesized by using Cu(NTf₂)₂, which was reduced by

copper metal in acetonitrile. Fehr et al. also described the

N

of organic transformations, such as C C-coupling reactions

or hydroamination of siloxy alkynes.^[12]In addition, AgNTf₂

has been applied as a transfer reagent for the introduction

G

ACHTUNGTRENNUNG

ꢀ

of the NTf₂moiety, for example, for metathesis reactions

within the preparation of trialkylsilyl and trialkylstannyl bis-

AHCTUNGTRENNUNG

(triflyl)imides^[2]and of catalytically active cationic gold(I)

synthesis of [Cu

A

bisACTHUNGETRNNUG

(triflyl)imides,^[12]in electrochemical studies^[7,8]and for

from copper(I) oxide and HNTf₂.^[4]Our interest in copper-

and silver-containing ILs such as thermally stable [Cu-

alkene/alkane separation processes.^[9,13,14]With respect to sil-

verꢀs lighter homologue copper, the existence of [Cu(CO)_n-

AHCTUNGRTEGNUN(N NTf₂)] (n=1–3) was reported, of which the dicarbonyl

complex was crystallographically characterized.^[1b]More-

over, it was patented that adsorbents of the type [CuL_nX]

(L=CO or olefin; nꢁ0) containing a uniform or complex

[a] Dr. M. Stricker, Dr. B. Oelkers, C. P. Rosenau,

Prof. Dr. J. Sundermeyer

ꢀ

monovalent anion X^ꢀ, for example, NTf₂, are applicable

Fachbereich Chemie, Philipps-Universitꢁt Marburg

Hans-Meerwein-Strasse, 35032 Marburg (Germany)

Fax : (+49)0642-1282-5711

for CO and olefin adsorption.^[1a]However, no example of a

Cu^I–bis

ACTHNUTRGNE(NUG triflyl)imide–olefin complex is given in this patent.

E-mail: jsu@staff.uni-marburg.de

Additionally, reportedly solvent-free CuNTf₂was used as a

Lewis acidic, reactive compound in a non-volatile liquid for

Supporting information for this article is available on the WWW

under http://dx.doi.org/10.1002/chem.201201740.

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Chem. Eur. J. 2013, 19, 1042 – 1057

FULL PAPER

safe storage and delivery of hazardous specialty gases, such

as PH₃and AsH₃.^[15]

In summary, the application of (ligand-deficient) Cu^Ior

ꢀ

Ag^Icompounds in combination with the NTf₂moiety

Since the beginning of the 20th century it is known that

copper(I) halides are capable of forming p complexes with

ethylene.^[16]In 1901, Berthelot showed that a complex with a

CuCl:C₂H₄ratio of 1:0.17 is formed when applying a hydro-

chloric acid solution of CuCl.^[16a]In contrast, ethylene under

pressure yields a 1:1 adduct with solid CuCl.^[16e]By the dis-

tribution method it was proven that olefins are prone to

form p complexes with silver(I) in aqueous solution.^[17]In

the case of ethylene the 1:1 complex is preferably formed.^[18]

Currently, regarding the selective absorption of an olefin

from an olefin/paraffin mixture, membrane-separation proc-

esses have become more and more important due to their

manifold ecological and economical advantages.^[19]More-

over, ionic liquids (ILs) are auspicious for the application in

facilitated transport membranes (FTMs), that is, immobi-

lized/supported liquid membranes (ILMs/SLMs), which re-

sults mostly from their high thermal stability and low vapor

pressure, as well as from their differing ability to dissolve

various gases.^[19a,20]It has been shown that pure RTILs, sil-

ver(I)–RTIL mixtures or even liquid compounds exhibiting

cationic silver(I) olefin complexes can be applied for the ab-

sorption of diverse alkenes.^{[9,13,14,21–23]}Huang et al. reported

on the synthesis of new Ag^I-containing ILs of the type [Ag-

seems to be promising for the accomplishment of one of

todayꢀs industrial challenges, namely olefin/paraffin separa-

tions. This is due to the fact that coinage metal compounds

readily form p complexes with unsaturated hydrocarbons, a

ꢀ

trend which is enhanced by the NTf₂moiety increasing the

Lewis acidity of the respective metal ion compared with the

respective triflates^[12]or chlorides.^[2]Consequently, there is a

demand for fundamental knowledge of the chemical and

structural characteristics of copper(I) and silver(I) bis-

AHCTUNGERTG(NNUN triflyl)imide. In this context we were particularly interested

in the determination of their solid-state structures that are

presented in the first part of this paper. The second part

deals with our results regarding the reactivity of 1–3 towards

the ionic liquid [emim]NTf₂and towards several olefins.

Within these investigations we succeeded in determining the

solid state structures of nine new compounds incorporating

ꢀ

the NTf₂anion. Finally, we studied the stability of several

in situ generated Cu^Iand Ag^Ibis

ACTHNUTRGNE(NUG triflyl)imide ethylene ad-

ducts by means of NMR spectroscopy.

Results and Discussion

A

Cu^Iand Ag^IBis(trifluoromethanesulfonyl)imide: Synthesis

and characterization: To prepare solvent-free CuNTf₂we ap-

plied the synthetic protocol described by Strauss^[1]and co-

the use in advanced liquid membranes.^[14]However, these

ILs have only been identified by means of ¹H NMR,

¹³C NMR and IR spectroscopies. Recently, the group of

Wasserscheid reacted AgNTf₂with gaseous propylene yield-

ing a liquid complex salt [Ag(propylene)_x]NTf₂with xꢂ1.7

at atmospheric propylene pressure. The separation of light

alkene/alkane mixtures in ILMs was suggested as a use for

this compound.^[9]For propene/propane separation, Steigel-

mann and Hughes (Standard Oil) developed a pilot plant

using the FTM technology.^[19a]Ortiz et al. studied mixtures

of AgBF₄and the room temperature ionic liquids (RTILs)

[bmim]BF₄and [bmpy]BF₄([bmim]⁺=1-n-butyl-3-methyli-

midazolium, [bmpy]⁺=N-butyl-4-methylpyridinium) for the

separation of propylene from propane.^[22]In addition, the

group of Meindersma investigated solutions of AgNO₃,

AgOTf and AgNTf₂in RTILs having the same anion in

each case for the ethylene/ethane separation.^[13]The prefer-

ential usage of silver(I) salts within studies concerning gas

separation processes probably results from their advantages

over copper(I) salts: They are stable against oxygen and hu-

midity, do not tend to undergo disproportionation reac-

tions,^[9]and reveal weaker p interactions favoring the rever-

sibility of the olefin coordination. However, the synthesis of

monomeric, bimetallic salts MM’X_n(M=group 11 metal,

preferably Cu; M’=group 13 metal, preferably Al) and

their application for complexation of ethylene, propene, and

CO was patented.^[24]To the best of our knowledge, despite

their potential use in technology, the interaction of CuNTf₂

and AgNTf₂with olefins has not yet been studied on a mo-

lecular basis, for example, by XRD studies.

[26]

workers. By reacting mesityl copper^[25]with HNTf₂they

obtained a pink-brown powder postulated to be solvent-free

CuNTf₂, which was not further characterized, but used as a

CO scavenger.^[1a]According to Strauss et al. the following

reaction takes place:

However, by means of NMR spectroscopy we realized

that mesitylene remains in the coordination sphere of the

copper(I) ion, even though the product was washed with n-

pentane and dried at 308C/10^ꢀ5mbar. Not only the signal of

the aromatic protons but also that of the methyl groups is

slightly shifted downfield with respect to uncoordinated me-

sitylene. Conversely, in the ¹³C NMR spectrum an upfield

shift is observed for all resonances. In the ¹⁹F NMR spec-

trum the signal of 1 is shifted upfield by about Dd=1 ppm

compared with that of the starting material HNTf₂. The ele-

mental analysis of the obtained colorless solid suggests a

ratio of 1:1 for CuNTf₂and mesitylene, which was also

proven by the result of the crystal structure analysis (see

below). The reaction, which actually takes place when con-

verting [CuACHTNUTRGENNG(U Mes)] with HNTf₂(1:1), is the following:

Chem. Eur. J. 2013, 19, 1042 – 1057

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www.chemeurj.org

1043

J. Sundermeyer et al.

The crystal structure of the ionic compound 1, comprising

the bis

(arene) Cu^Ication [Cu(h³-MesH)₂]⁺and the cupra-

te(I) anion [Cu

(NTf₂)₂]^ꢀ, is shown in Figure 1. All relevant

turally characterized d¹⁰metallate of the type [M

ACHTUNGTRENNUNG(NTf₂-

G

E

kN)₂]^ꢀ(M=any transition metal). Within the herein pre-

sented studies this structural motif was observed in another

case (see below). Moreover, compound 1 is also a rare ex-

ACHTUNGTRENNUNG

ꢀ

ample of a solid-state structure containing the NTf₂anion

in the kN coordination mode,^[30]which is expected for soft

metal ions, for example, copper(I),^[1b]silver(I),^[31,32]

gold(I),^[33]and iron(II).^[10]In 1 the copper atom is linearly

coordinated by the two NTf₂entities with a(N1-Cu1-

ꢀ

N1’’)=179.50(17)8. The Cu1 N1 distance is found to be

1.890(3) ꢃ and thus in the expected range for copper(I)

being linearly coordinated by two NQ₂(Q=non-metal) moi-

eties.^[34]The two SNS planes are twisted with respect to each

other at an angle of 49.58.

Facing the problem that [CuACTHNUGTRNNEUG ACHUTGNTREN(NUNG NTf₂)₂] (1) is

(h³-MesH)₂][Cu

Figure 1. Molecular structure of [Cu

created by inversion symmetry or due to a C₂rotation axis are marked

by (’) and (’’), respectively.

(h³-MesH)₂][Cu

E

an inconvenient starting material for further reactions due

to the expected release of mesitylene (b.p. 163–1658C) we

recrystallized 1 from a highly diluted ethereal solution at

ꢀ208C yielding single crystals of the diethyl ether adduct of

copper(I) bis(trifluoromethanesulfonyl)imide, that is, [Cu-

parameters concerning the crystal structure determinations

of 1–3 are listed in Table S1 of the Supporting Information.

In addition, selected bond lengths and angles of all structur-

ally characterized compounds are given in the Supporting

Information.

ACHUTNGREN(NUG Et₂O)ACHUTNGTNERN(GUN NTf₂)] (2), instead of solvent-free CuNTf₂:

Compound 1 is only the second example of a homoleptic

Cu^Iarene sandwich complex characterized by an X-ray crys-

tal structure determination. The first example, namely

Both the proton and the carbon NMR spectrum only

[Cu(1,2-F₂C₆H₄)₂)][Al(OC

G

show downfield-shifted signals for the diethyl ether due to

complexation. Compounds 1 and 2 show only slightly differ-

ent values for d_F.

The crystal structure of 2 is depicted in Figure 2. The cop-

per(I) ion reveals a linear coordination with an O5-Cu1-N1

group of Krossing in 2009.^[27]In the inversion symmetric

sandwich complex cation of 1 all of the twelve Cu C distan-

ces varying from 1.962(4) to 3.037(4) ꢃ are within the sum

of the van der Waals radii of copper and carbon (3.1 ꢃ^[28]).

In contrast, each of the two independent centrosymmetric

cations of [Cu(1,2-F₂C₆H₄)₂)][Al(OCACHTUNGRTNE(UNG CF₃)₃)₄] exhibits only

ꢀ

four Cu C contacts being that short (d

(Cu C)=2.085(8) ꢃ–

3.026(7) ꢃ). The bonding situation of the arene ligands of

the [Cu(1,2-F₂C₆H₄)₂)]⁺cation was described as a h¹/h²coor-

dination or as a h³/h⁴coordination considering much weaker

[27]

ꢀ

Cu C interactions.

The authors of a theoretical study

dealing with Cu⁺p interactions report that copper(I) is

prone to adopt the h²coordination mode with aromatic

compounds in the condensed phase if a coordinating coun-

terion is present. Moreover, within their studies concerning

cation–p complexes of Cu^Iwith 1,3,5-trisubstituted ben-

zenes, Zhang et al.^[29]found that electron-donating groups,

such as methyl substituents, contribute to the enhancement

of the binding energy of such complexes. For the [Cu-

[29]

ꢀ

Figure 2. Molecular structure of [CuACHTNUGRTENNUG(Et₂O)ACHTUNTGERN(NUGN NTf₂)] (2).

ꢀ

(MesH)₂]⁺cation in 1 we suggest a h³coordination as the

angle of 178.81(13)8. The NTf₂anion serves as monoden-

tate N-donor ligand as in the case of 1. Complex 2 is a rare

example^[35]of a crystal structure with a Cu^Iion being linear-

ly coordinated by one N-donor and one O-donor ligand.

There exist several solid-state structures revealing tetrahy-

drofuran in the coordination sphere of copper(I), but only a

single one in which diethyl ether is bonded to a Cu^Iion:

best description, regarding only the six most significant

ꢀ

Cu C interactions varying from 1.962(4) to 2.456(4) ꢃ. In

contrast, at room temperature in solution the cation seems

to reveal D_3hsymmetry, as is suggested by the signal pat-

1

terns of the H and ¹³C NMR spectra. This is due to either a

h⁶coordination or a fluctuating coordination of the mesity-

lene ligands that cannot be resolved on the NMR timescale.

According to a search in the Cambridge Structural Data-

base, the cuprate(I) anion of 1 is the first example of a struc-

{=CR¹(OR²)} (Et₂O)]PF₆(R¹=(E)-CH=CH-2-

[CuACHTUNGTERNNNUG ACHTUTNGRENNUG AHCTUNGERTG(NNNU CH₃CN)ACHTGUNTRENNUGN

furyl, R²=(1R,2S,5R)-menthyl).^[36]In the latter compound,

ꢀ

the Cu O distance is found to be 2.345(2) ꢃ and therefore

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Chem. Eur. J. 2013, 19, 1042 – 1057

Copper(I) and Silver(I) Bis(trifluoromethanesulfonyl)imide

FULL PAPER

significantly longer than the relevant one of complex 2

ꢀ

(d

G

I

different coordination geometries at Cu . No additional Cu

O contacts below the sum of the van der Waals radii are ob-

served in the case of

(Cu1…O3)=2.984(2) ꢃ). The Cu1 N1 bond length of 2

(1.901(2) ꢃ) is significantly shorter than the corresponding

one in [Cu(CO)₂A

(NTf₂)]^[1b](2.029(4) ꢃ), which is due to the

2

(dACTHNGUETRNNU(G Cu1…O1)=2.998(2) ꢃ,

ꢀ

dACHTUNGTRENNUNG

CHTUNGTRENNUNG

different coordination geometries at the copper atom: linear

versus trigonal planar. This statement is evidenced by the

statistical evaluation of two searches in the Cambridge

Structural Database.^[37]

In the case of AgNTf₂(3) manifold preparation methods

are described in the literature.^[2,7–11]In addition, compound 3

[2,9,11]

has been characterized by means of NMR

and IR^[2,9]

spectroscopies, ESI mass spectrometry,^[9]and elemental

analysis.^[2,8,10]

Within the herein presented studies, two different synthet-

ic strategies were applied for the preparation of AgNTf₂(3).

At first, compound 3 was prepared according to a slightly

modified literature method,^[9]namely from Ag₂O and

HNTf₂in aqueous solution, and recrystallized from dichloro-

methane:

Figure 3. Top: AgNTf₂unit within the crystal structure of [AgNTf₂]₁(3).

Bottom: layered structure of [AgNTf₂]₁(3), view along the a axis.

Atoms generated by symmetry are not distinguished by primes.

Furthermore, we applied the same procedure as in the

case of 1 and thus started from [AgACTHNURGTENUNG(Mes)]₄and HNTf₂.

Structural Database revealing the coordination number

seven for silver(I).^[39]

[25]

However, instead of a mesitylene complex analogous to 1,

pure AgNTf₂(3) was obtained in good yield:

The layered structure of 3 exhibits two crystallographical-

ly different rhombic Ag₂ACTHNUTRGNE(UGN m-O)₂cores as a significant struc-

tural motif, which is due to the fact that the oxygen atoms

O11 and O13 bridge the Ag^Iions along the b axis. In addi-

ꢀ

tion, every NTf₂anion interconnects five silver atoms. Al-

together, three coordination modes are adopted by the five

ꢀ

donor atoms of each NTf₂ligand: kN by N11, kO for O12

The fluorine spectrum of 3 in [D₂]CH₂Cl₂shows only one

signal at d=ꢀ74.8 ppm, which is identical to the d_Fvalue of

1. Because of the poor solubility of 3 in CH₂Cl₂the carbon

NMR spectrum was recorded in [D₂]CH₂Cl₂/[D₈]THF at a

ratio of 11:1. In comparison with the literature known

values for d_Cof tetrahydrofuran^[38]the ¹³C NMR resonances

of the cyclic ether are shifted upfield due to interaction with

and O14 as well as m-O in the case of O11 and O13. All

ꢀ

Ag O bond lengths (2.458(4)–2.849(4) ꢃ) are within the

sum of the van der Waals radii of silver and oxygen

[32]

(3.2 ꢃ^[28]). For the silver(I) complex [Ag

N

ACHTUNGTRNE(NUNG NTf₂)]₆

(bet=N,N,N-trimethylammonioacetate)

one

ꢀ

(CF₃SO)O Ag contact is reported being 2.529(4) ꢃ and

therefore within the range found for 3. The shortest of the

the coinage metal. When dissolving compound

3

in

Ag N

(Tf₂) distances in [Ag

E

(NTf₂)]₆,^[32]ranging between

ꢀ

[D₄]MeOH to compare the spectroscopic data to that re-

ported in the literature,^[9]formation of elemental silver was

observed.

2.430(5) and 2.808(6) ꢃ, is similar to that of 3 (d

G

ꢀ

N11)=2.411(4) ꢃ). However, the Ag N bond in 3 is signifi-

cantly longer than those reported for a silver(I) complex of

ꢀ

Single crystals of 3 were obtained when trying to crystal-

a dimeric paracyclophane containing kN-coordinated NTf₂

:

lize [emim][Ag

N

2.345(5) and 2.369(5) ꢃ.^[31]

Figure 3 shows both a AgNTf₂unit within the crystal struc-

ture of 3 and the layer structure of 3.

Reactivity of 1—3: Reactivity towards [emim]NTf₂: The cop-

per(I) compound [Cu(Et₂O)(NTf₂)] (2) and [emim]NTf₂

were blended at a molar ratio of 1:1 yielding analytically

pure [emim][Cu(NTf₂)₂] (4). Applying AgNTf₂(3) instead

of 2 gives the analogous silver(I) compound, namely [emim]

[Ag(NTf₂)₂] (5).

Compound 3 forms a layered structure, the layers are sep-

arated by CF₃groups facing towards each other. Every

silver atom is coordinated by six oxygen atoms and one ni-

trogen atom. Up to now there are fifteen examples of orga-

nometallic solid state structures listed in the Cambridge

G

ACHTUNGTRENNUNG

AHCTUNGTRENNUNG

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1045

J. Sundermeyer et al.

ꢀ

distances have values of 1.900(3) ꢃ (d

N

ꢀ

1.896(4) ꢃ (d

A

not only in the expected range,^[34]but also nearly identical

ꢀ

to those found for the anion in 1 (d

G

In this context it should be mentioned that Meindersma

and co-workers used mixtures of 3 and [emim]NTf₂for eth-

ylene extraction,^[13]but did not clarify the nature of the sil-

ver(I) species involved. Metallate complexes containing co-

In contrast to the solid state structure of 1, the C₂rotation

axis is identical to the N21-Cu1-N22 axis and not perpendic-

ular to it. Consequently, the SNS planes of the anion are

twisted with respect to each other at an angle of 83.68. Be-

tween the imidazolium cation and two different cuprate(I)

anions exist two short intermolecular contacts that are

below the sum of the van der Waals radii of the relevant

ꢀ

ordinated NTf₂ligands have been thoroughly investigated

by Mudring et al. for alkaline earth metals and lantha-

nides.^[40]Very recently, a homoleptic argentate anion with

ꢀ

three NTf₂

ligands has been described in [Ag-

atoms: dACTHNGUTERNNUG

(O21…H11)=2.39 ꢃ (S(vdW radii)=2.9 ꢃ^[28]) and

A

U

d(F25…H14 A)=2.37 ꢃ (S(vdW radii)=2.9 ꢃ^[28]).

Compared with the proton and the carbon NMR spectra

of [emim]NTf₂both for 4 and for 5 the C2 and H2 signals of

the imidazolium ring are most significantly affected upon

the formation of 4 and 5. The upfield shifts of these reso-

nances, which are found to be more significant in the case of

4, might be due to the loss of cation–anion interactions in

Reactivity towards COD: The reaction of 1–3 with 2.5 equiv-

alents of 1,5-cyclooctadiene (COD) gave the analytically

pure compounds [M

ed.

ACHTUGNRTEN(NUGN cod)₂]NTf₂(M=Cu 6, Ag 7), as expect-

ꢀ

solution: Hydrogen bonds between the NTf₂anion and the

proton in 2-position of the imidazolium cation are blocked

by coordination of the anion to copper(I) or silver(I). The

d_Fvalue of 4 and 5 is shifted to lower field by about Dd=3

and 2 ppm, respectively, in comparison to [emim]NTf₂.

The high resolution negative atmospheric-pressure chemi-

cal ionization (APCI) mass spectrum of 5 shows the signal

assigned to the argentate(I) anion as the main peak, where-

as the analogous signal of the cuprate(I) anion of 4 is not

observed by means of APCI mass spectrometry.

The crystal structure of 4 is depicted in Figure 4. All rele-

vant parameters concerning the crystal structure determina-

tions of 4 and 6–10 are listed in Table S2 of the Supporting

Information. The crystallographically important parameters

of 12, 12a, and 13 are given in Table S3 of the Supporting

Information.

1

With respect to the H NMR spectrum of free COD, both

6 and 7 show slightly downfield-shifted signals of the CH

groups due to complexation, whereas the resonances of the

CH₂groups are essentially not influenced. For the olefinic

protons of 6, a Dd_Hvalue of approximately Dd=0.3 ppm is

determined, whereas for the CH protons of the silver(I)

complex 7, the Dd_Hvalue is somewhat larger at approxi-

mately Dd=0.5 ppm. The ¹³C NMR spectra of 6 and 7 are

identical with the following exception: Compared with free

COD, the signal of the CH groups is shifted upfield by

almost Dd=6 ppm in the case of 6, whereas the respective

Dd_Cvalue of 7 is found to be approximately Dd=2 ppm. In

comparison with the relevant starting materials, the d_Fre-

veals an upfield shift of approximately Dd=3 ppm for 6 and

7, respectively. The complex cation [M

also exists in solution, which is in accord with the observa-

tions for [Cu(cod)₂]ClO₄and [Ag(cod)₂]BF₄in

[D₆]acetone^[41]and for [Ag(cod)₂]ClO₄in [D₃]CH₃CN.^[42]

(cod)₂]⁺probably

ACHTUNGTRENNUNG

G

ACHTUNGTRENNUNG

AHCTUNGTRENNUNG

The IR spectrum of COD exhibits two frequency regions

that are affected significantly upon coordination to a metal

ion, namely the C=C stretching mode of uncoordinated

COD between 1655 to 1660 cm^ꢀ1[43,44]and two C=C H de-

ꢀ

Figure 4. Crystal structure of [emim][CuACTHNUTRGNEUNG(NTf₂)₂] (4). The second position

formation frequencies at 722 and 710 cm^ꢀ1.^[43]For compari-

son, the relevant data of 6 and of similar complexes descri-

bed in the literature^[43,44]is given in Table 1. The authors of

all studies quoted in Table 1 report a C=C vibration roughly

between 1590 and 1600 cm^ꢀ1for the copper(I)-COD com-

plexes.

of the disordered imidazolium cation is omitted for clarity. Atoms

ꢀ

marked (’) and non-labeled atoms of the NTf₂ligands are symmetry-

generated.

The cuprate(I) anion of 4 reveals the same coordination

mode as the respective anion in complex 1. However, the

crystallographically imposed symmetry of 4 implies a value

of 180.08 for the N21-Cu1-N22 angle. The copper-nitrogen

For 6 and 7 the C=C stretching vibration is shifted to

lower frequencies only by 65 and 54 cm^ꢀ1, respectively, with

regard to uncoordinated COD. In contrast, in the case of

1046

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Chem. Eur. J. 2013, 19, 1042 – 1057

Copper(I) and Silver(I) Bis(trifluoromethanesulfonyl)imide

FULL PAPER

Table 1. IR frequencies (in cm^ꢀ1) of [Cu

ACTHNUTRGENN(GU cod)₂]ACHUTNGTREN(NUGN WCA) (WCA=weakly

coordinating anion).

ꢀ

free COD

BF₄

ClO₄

NTf₂^ꢀ(6)^[a]

n

(C=C)

1656^[a]

1655^[43]

1660^[44]

1588^[43]

1590^[43]

1591

1638, 1595^[44]

d

(C=C-H)

720, 706^[a]

722, 710^[43]

770, 740^[43]

791, 735^[b]

[a] Own measurements. [b] Preliminary assignment of the bands due to

strongly interfering spectral region.

Figure 6. Molecular structure of [AgACHTNUGTRNEUNG(cod)₂]NTf₂(7). Atoms labeled with

(’) or (’’) are generated by symmetry.

the isovalence-electronic [Ni

the Dn

(C=C) value is found to be 328 cm^ꢀ1.

(C=C)=1328 cm^ꢀ1[45]

ACHTUNGETRN(NUNG cod)₂] (nACHTUGNTRENNUGN )

ACHTUNGTRENNUNG

In comparison with zerovalent d¹⁰metals like nickel(0),

both Cu^Iand Ag^Ishow much weaker p-bonding ability to-

wards s donor/p acceptor ligands such as olefins.^[46]This dif-

ference can be correlated to the differing promotion ener-

gies,^[47]which is evidenced by the above-mentioned values

planes (C1-C2)_centroid-Cu1-(C5-C6)_centroidand (C9-C10)_centroid-

Cu1-(C13-C14)_centroiddetermined at 88.08 implies a slightly

distorted tetrahedral coordination. The distances between

Cu1 and the olefinic carbon atoms range from 2.227(6) to

2.329(5) ꢃ and are thus similar to those of [Cu-

for n

(C=C).

(cod)₂]ClO₄,^[41,48]revealing values between 2.253(3) and

ACHTUNGTRENNUNG

Complex 6 crystallizes in the triclinic space group P1 with

Z=2, whereas compound 7 crystallizes in the monoclinic

space group C2/c with Z=4. Thus, compounds 6 and 7 are

not isotypic. In the solid state structures of 6 and 7 the

COD moieties do not reveal the ’’boat’’ conformation as ob-

2.273(3) ꢃ.^[48]The double bonds in 6 (d

1.373(7) ꢃ) are in part shorter than those of the neutral d¹⁰

complexes [Ni

(cod)₂]^[49](1.384(11)–1.392(13) ꢃ; measured at

ca. 295 K) and [Pt

(cod)₂]^[50](1.329(8)–1.470(9) ꢃ; measured

ACHTUNGTREN(NGNU C=C)=1.337(8)–

¯

AHCTUNGTRENNUNG

at 200 K), which is in accordance with the different p-back-

donation characteristics of copper(I) and the zerovalent

group 10 metals nickel(0) and platinum(0), expressed by

their promotion energies (see the above IR discussion).^[47]

In compound 7, silver(I) also adopts the tetrahedral coor-

dination. In contrast to 6, a higher distortion is observed as

the dihedral angle between the planes (C1-C2)_centroid-Ag1-

(C5-C6)_centroidand (C1’-C2’)_centroid-Ag1-(C5’-C6’)_centroidis

83.98. The four different distances between Ag1 and the ole-

finic carbon atoms, which vary from 2.4307(18) to

2.5405(19) ꢃ, are significantly longer than the corresponding

ones in the analogous Cu^Icompound 6. Additionally, the

served in the presence of highly symmetrical weakly coordi-

ꢀ [42,48]

nating anions, that is, cubic ones like ClO₄,

but the

’’twisted-boat’’ conformation.

In contrast to all other solid state structures presented

herein, compounds 6 and 7 are the only ones containing

ꢀ

NTf₂as non-coordinating anion. In both cases the transoid

configuration is adopted, that is, the CF₃groups are located

at different sides with respect to the SNS plane. Whether

the bisACHTUNGTRENNUNG(triflyl)imide anion is cisoid- or transoid-configurated

ꢀ

is evidenced by the C C distance of approximately 4

(cisoid) and 5 ꢃ (transoid), respectively. A statistical evalua-

tion of a search in the Cambridge Structural Database pre-

dicated on this criterion did not result in a trend regarding

the preference of one configuration, for example, dependent

on the coordination mode. Figure 5 shows the crystal struc-

ture of 6, whereas the crystal structure of 7 is depicted in

Figure 6.

ꢀ

average value of d(Ag C_olefin) is comparable to those of

[Ag

G

ꢀ [51]

ꢀ [42]

BF₄,

1.341(3) and 1.345(3) ꢃ are in part shorter than in the case

of [Ni

(cod)₂]^[49]and [Pt(cod)₂]^[50]with differences being mar-

PF₆^ꢀ[52]). The C=C distances in 7 being

A

ACHTUNGTRENNUNG

ginally larger than for 6 (see above). This is in compliance

with the fact that Ag^Ireveals a slightly higher promotion

energy than Cu^I.^[47]

Each of the two COD molecules in 6 adopts the typical

h²:h²coordination mode. The dihedral angle between the

Reactivity towards NBD: The reaction of 1–3 with 2,5-nor-

bornadiene (NBD) yielded the monomeric copper(I) com-

plex [Cu

pounds [Cu₂(h²:h²-nbd)

(NTf₂)]₁(10).

The molar olefin/metal ratios applied for the synthesis of

(h²-nbd)

ACHUTNGTRENNUG ₂ACHTUNGTRENNUNG

(NTf₂)] (8) as well as the polymeric com-

AHCTUNGTRENNUNG

8–10 are given in Table 2.

By analyzing the proton and carbon NMR spectra of 8,

C_2vsymmetry is suggested for NBD, although only one of

the double bonds of the diolefin is coordinated to the metal

in the solid state (see below). In the ¹H NMR spectrum,

only the signal assigned to the bridgehead protons is affect-

Figure 5. Molecular structure of [CuACHTUNTGRNEUNG(cod)₂]NTf₂(6).

Chem. Eur. J. 2013, 19, 1042 – 1057

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www.chemeurj.org

1047

J. Sundermeyer et al.

[55]

of

[Ag₂(h²:h²-nbd)

(NO₃)₂]₁

and

[Ag(h²:h²-nbd)-

AHCTUNGTRENNUNG

(ClO₄)]₁,^[56]exhibiting a medium band at 1470 and at

1485 cm^ꢀ1, respectively. Remembering the frequency of the

relevant absorption band of [Cu₂(h²:h²-nbd)

(NTf₂)₂]₁(9)

AHCTUNGTRENNUNG

(nACTHNUTRGNEUNG

(C=C)=1456 cm^ꢀ1) the differences concerning the p-back-

bonding characteristics of Cu^Iand Ag^Ibecome evident

again.

The molecular structure of [CuACHTNUTRGENNUG ₂ACHTUNGTREN(NGUN NTf₂)] (8) is de-

(h²-nbd)

picted in Figure 7.

Table 2. Molar olefin/metal ratios within the syntheses of 8–10. [Cu

MesH)₂][Cu(NTf₂)₂] (1), [Cu(Et₂O)(NTf₂)] (2) and AgNTf₂(3) were used

as starting materials.

(h³-

ACHTUNGTRENNUNG

A

R

ACHTUNGTRENNUNG

1

2

3

[Cu

[Cu₂(h²:h²-nbd)

[Ag(h²:h²-nbd)

(NTf₂)]₁(10)

(h²-nbd)

R

2.5

2.6

–

[c]

G

0.5^[a]/2.5^[b]

–

2.5^[d]

[a] Concentration with respect to copper: approximately 0.5 molL^ꢀ1

.

[b] Concentration with respect to copper: approximately 0.2 molL^ꢀ1

[c] Not carried out. [d] Concentration with respect to silver: approximate-

ly 0.5 molL^ꢀ1

.

Figure 7. Molecular structure of [CuACHTNUTRGENNUG ₂ACHTUNTGERN(NGUN NTf₂)] (8). Atoms labeled

(h²-nbd)

(’) are symmetry-generated.

ed upon coordination to the Cu^Iion, namely by a slight

downfield shift. The carbon NMR spectrum of 8 shows the

most significant influence for the olefinic carbon atoms, that

is, a shift to higher field by about Dd=6 ppm. The CH₂

group is also upfield-shifted by approximately Dd=3 ppm.

The d_Fvalue of 8 is similar to that observed for the starting

materials 1 and 2.

Compound 8 is the first example of a structurally charac-

ꢀ

terized copper(I)–NBD 1:2 complex. The Cu1 N1 bond

length (2.055(3) ꢃ) is comparable to the corresponding

ꢀ

value of [Cu(CO)

angles of 122.98 ((C3-C4)_centroid-Cu1-(C3’-C4’)_centroid

(NTf₂)]^[1b](d

E

The relevant C=C stretching vibrations for the free diene

were determined at 1641, 1543, 724, and 655 cm^ꢀ1. The IR

spectrum of 8 exhibits the C=C vibrations at 1561 and

1457 cm^ꢀ1. Additionally, a single band corresponding to

118.68 ((C3-C4)_centroid-Cu1-N1) the geometry at Cu1 is trigo-

nal planar. In the case of [Cu₂(h²:h²-nbd)

AHCTUNGTRENNUNG

(Figure 8), the coordination mode of the two crystallograph-

ically different Cu^Iions can be described as distorted trigo-

nal planar. A section of the solid-state structure of the poly-

dACHTUNGTRENNUNG

(C=C-H) occurs at 689 cm^ꢀ1. These findings for 8 are in

compliance with those reported for copper(I)–NBD com-

plexes containing h²-coordinated NBD ligands.^[43,53,54]

In contrast to complex 8, the infrared spectrum of 9 re-

meric compound [Cu₂(h²:h²-nbd)

ACTHUNRGTNEG(UN NTf₂)₂]₁(9) is shown in

Figure 8.

veals only one very weak band for the C=C stretching vibra-

The solid-state structure of compound 9 exhibits two inde-

pendent copper(I) bis(trifluoromethanesulfonyl)imide units.

On the one hand, there are centrosymmetric eight-mem-

bered rings consisting of two CuNTf₂entities that are con-

ꢀ1

ꢀ

tion at 1456 cm , whereas the bands related to the C=C H

deformation modes are not observed. These findings are

typical of a h²:h²-bound NBD ligand.^[43]Additionally, the

band assigned to the rocking of the methylene group does

not occur.

ꢀ

nected in a 1kN:2kO coordination mode. The Cu1 N1 bond

ꢀ

length is found to be 2.012(6) ꢃ and the Cu1 O2’ bond

The proton, carbon, and fluorine NMR spectra in

[D₂]CH₂Cl₂of the polymeric silver(I) compound 10 with

h²:h²-bound NBD moieties exhibit major differences with

respect to the monomeric copper(I) complex 8 containing

1

NBD as an h²-coordinated ligand. Generally, in both the H-

and ¹³C NMR spectrum of 10, all the NBD resonances are

shifted to lower field upon complexation, whereas d_Fis

(within the limits of error) identical to the relevant chemical

shift of the starting material 3. The signals of the protons

are more strongly affected than in the case of 8, in which

the largest deshielding is found for the olefinic protons with

Dd_Hvalues of approximately 0.5 ppm.

Figure 8. Section of the layered structure of [Cu₂(h²:h²-nbd)

ACTHUNRGTNEUGN(NTf₂)₂]₁(9).

The second position of the disordered SO₂CF₃group located at S3 is

omitted for clarity.

In the IR spectrum of 10 the C=C stretching frequency

occurs at 1485 cm^ꢀ1, which is in accordance with the spectra

1048

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Chem. Eur. J. 2013, 19, 1042 – 1057

Copper(I) and Silver(I) Bis(trifluoromethanesulfonyl)imide

FULL PAPER

length is 2.086(5) ꢃ. A search in the Cambridge Structural

A section of the crystal structure of [Ag(h²:h²-nbd)-

ꢀ

Database regarding the common ranges for d

(Cu N) and

ACHTUGNRTEN(NUGN NTf₂)]₁(10) is shown in Figure 9.

1

2

3

ꢀ

dA

(Cu O) in the structural motif CuL₃(L =N, L =O, L =

non-metal) resulted in a broad distribution in each case. The

ꢀ

maximum for d

1.9 ꢃ, whereas the most frequent value for d

G

termined at approximately 2.3 ꢃ. Interestingly, the triflate,

which is also commonly regarded as a weakly coordinating

anion, forms an analogous structural motif in the solid-state

structure of [Cu₂ACHTUNGTRENNUNG ACHTUGNTRNEN(UGN OTf)₂]₁, namely

(PPh₃)₂{h²:h²-isoprene}

eight-membered [CuSO₂]₂-rings.^[57]On the other hand, the

copper atom Cu2 in 9 also has two crystallographically iden-

Figure 9. Helix-like [Ag(h²:h²-nbd)

ACHTNUTRGNEUG(N NTf₂)]₁-strand in the crystal of 10,

view along the c-axis. Uncoordinated atoms of the NTf₂ligands are

omitted for clarity. Atoms labeled (’) are generated by symmetry.

ꢀ

tical NTf₂ligands in its coordination sphere, of which one

ꢀ

is k²N,O-coordinated and the second one is kO-bound. The

crystal structure of 9 comprises CuNTf₂strings along the a

ꢀ

axis as a second structural motif. The Cu2 N2 distance is

2.015(7) ꢃ, which is nearly identical to the value determined

Compound 10 is the third example of a structurally char-

acterized silver(I)–NBD compound revealing the starting

materials in a 1:1 stoichiometry. The crystal structure of 10

ꢀ

for Cu1 N1. One of the two Cu2 O bond lengths, namely

dACHTUNGTRENNUNG(Cu2 O8’)=2.053(6) ꢃ, is in the same range as dCAHTUNGTRNE(NUGN Cu1

O2’). There exists a weak secondary interaction between

(Cu2 O7)=2.871(6) ꢃ). The two basic struc-

tural motifs of the solid state structure of 9, that is, the

ꢀ

comprises polymeric helices of [Ag

(Figure 9), at which the three independent silver atoms are

(nbd)₃]³⁺units

₃ACHTUNGTRENNUNG

ꢀ

Cu2 and O7 (d

U

2

ꢀ

interconnected by h :h -bound NBD ligands with Ag C_olefin

A

{(NTf₂)₂-1kN:2kO;1kO:2kN}] rings and the (NTf₂-

distances between 2.377(8) and 2.494(9) ꢃ. In comparison,

1k²N,O:2kO)-copper(I) strands along the a axis, are bridged

by h²:h²-coordinating NBD ligands, resulting in an strongly

undulating sheet structure.

the corresponding values of [Ag(h²:h²-nbd)

ACHTUNGRETNNU(G ClO₄)]₁varying

from 2.416(7) to 2.472(8) ꢃ^[56]are within the range deter-

mined for 10, whereas most of the relevant distances of

Selected bond lengths of NBD,^[58]8, 9 and comparative

ACTHNGUTERNNUG

[Ag(h²:h²-nbd)(NO₃)]₁(2.496(6)–2.561(6) ꢃ^[42]) are above

ꢀ

complexes are listed in Table 3. The Cu C_olefindistances in 8

are found to be significantly longer than those determined

those of 10. The mentioned valuations for the Ag C_olefindis-

tances suggest a similar coordination sphere for the silver

ACTHNGUTERNNUG

atoms in 10 and [Ag(h²:h²-nbd)(ClO₄)]₁,^[56]which is in com-

pliance with the bonding situations in their solid-state struc-

ꢀ

for 9. The values of d(Cu C_olefin) in 9 differ less from each

other than those of [Cu₄Cl₄(h²:h²-nbd)₂]₁.^[59]Interestingly,

the literature-known Cu^I–NBD complexes incorporating

tures. However, taking into account that one of the two

2

crystallographically independent silver atoms in [AgACHTUNGTRENNUNG

(h²:h²-

ꢀ

h -coordinated NBD show Cu C_olefindistances similar to

[42]

those of 9 instead of 8, for example in [CuCl

A

nbd)

N

has three s-donors in its coordination

In the case of isostructural [CuBrACHTUNGTRNEUNG

(h²-nbd)]₄, at least one

sphere (instead of two as in 10 and [Ag(h²:h²-nbd)-

value is within the range of 9.^[60]The copper atom in 8 is co-

ordinated by one s donor and two p acceptors, whereas up

to three donor atoms and only one p acceptor are present in

all other cases. Consequently, the copper atom in 8 is less

electron rich and thus a weaker p-donor, which explains the

(ClO₄)]₁)^[56]the Ag C_olefindistances should be at least in

part shorter due to the comparatively larger p-donor ability

of one of the crystallographically different silver atoms in

this compound. This finding may be attributed to steric rea-

sons.

ꢀ

deviation in d(Cu C_olefin) of 8, 9 and the literature-known

In Table 4 the C=C bond lengths of NBD,^[58]10 and of

two literature-known complexes are given.

ꢀ

complexes. Both the coordinated double bond of the h²-

bound NBD ligand in 8 and those in 9 are longer than the

C=C bond of free NBD in the solid state.

Besides two NBD ligands, every Ag^Iion in 10 has two s-

donors in its coordination sphere, namely two oxygen atoms

(Ag3) or one nitrogen atom and one oxygen atom (Ag1,

Ag2), belonging to one or two

ꢀ

Table 3. Selected bond lengths d (in ꢃ) of NBD,^[58]8, 9, and of the comparative complexes [CuX

(h²-nbd)]₄

ACHTUNGTRENNUNG

ꢀ

NTf₂units. The Ag N bond

lengths are found to be

2.298(7) and 2.544(6) ꢃ and

are therefore far below the

sum of the van der Waals radii

(X=Cl,^[59]Br^[60]) and [Cu₄Cl₄(h²:h²-nbd)₂]₁.^[59]

[c]

[d]

[c]

NBD^[a]

8^[b]

9^[b]

[CuCl

N

[CuBr

N

ACHTUGTNRENNUG[Cu₄Cl₄ACHTUGNTERN(NUGN nbd)₂]₁

ꢀ

Cu C_olefin

–

2.176(2)

2.166(2)

–

1.354(3)

–

1.322(3)

2.030(7)

2.034(7)

2.069(8)

2.076(7)

1.365(10)

1.383(11)

–

2.052(8)

2.072(9)

–

1.335(12)

–

1.280(12)

2.052(10)

2.110(11)

2.021(6)

2.045(7)

2.115(7)

2.135(8)

1.332(11)

1.381(10)

–

of

silver

and

nitrogen

(3.3 ꢃ^[28]). The values for d-

C=C coord.

1.345(17)

–

1.333(17)

ꢀ

(Ag O)

varying

from

2.405(7) ꢃ to 3.081(7) ꢃ are all

within the sum of the relevant

van der Waals radii (3.2 ꢃ^[28]),

C=C uncoord.

1.337(1)

[a] Determined at approximately 110 K. [b] Determined at 100(2) K. [c] Determined at approximately 298 K.

[d] Determined at approximately 138 K.

Chem. Eur. J. 2013, 19, 1042 – 1057

ꢂ 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

www.chemeurj.org

1049

J. Sundermeyer et al.

Table 4. Lengths d (in ꢃ) of the coordinated C=C bonds in 10 and in the

[42]

comparative compounds [Ag(h²:h²-nbd)

(ClO₄)]₁.^[56]For the purpose of comparison: d

NBD is 1.337(1) ꢃ.

N

and [Ag(h²:h²-nbd)-

N

ACHTUNGTRENNUNG

[b]

[c]

10^[a]

[AgNO

E

G

₄ACHTUNGTNER(NUNG nbd)]₁

C=C, min^[d]

C=C, max^[d]

1.295(13)

1.355(12)

1.307(10)

1.346(13)

[a] Determined at 193(2) K. [b] Determined at approximately 300 K.

[c] Determined at approximately 296 K. [d] Min indicates the shortest C=

C bond length, whereas max indicates the longest.

Reactivity towards ethylene: In most of the structurally char-

acterized copper(I) ethylene complexes, the metal exhibits

up to three N-donor ligands and one olefin molecule in its

coordination sphere.^[64]One example is found in which two

but cover a wider range than found for the starting material

3 (2.458(4)–2.849(4) ꢃ). The helix-like strands of 10 are

cross-linked by two of the three crystallographically differ-

ethylene molecules and AlCl₄are bound to the Cu^Iion.^[65]

ꢀ

ent NTf₂ligands resulting in a three-dimensional network.

In 2007 Krossing and co-workers^[66a]succeeded in isolating

the first homoleptic Cu^Iethylene complex cation, namely

Reactivity towards isoprene: Copper(I) and silver(I) com-

plexes with non-cyclic, low-boiling diolefins such as 1,3-buta-

diene have been of scientific and industrial interest for a

long time.^[14,61]Nevertheless, only three crystal structures are

known for this type of compound; one incorporates 1,3-bu-

tadiene^[62]and two exhibit isoprene.^[57,63]Preliminary data

show that it is possible to obtain a defined Ag^Ibis-

[CuACTHNUGRTNENUG ACHUTNGTRENNUGN

(C₂H₄)₃]⁺, by using [Al(OC(CF₃)₃)₄]^ꢀas a WCA. Only a

few months later Dias et al.^[67]reported preliminary results

regarding the synthesis of an analogous copper(I) ethylene

ꢀ

complex, yet revealing the sterically less demanding SbF₆

anion.

Up to now eleven silver(I) ethylene complexes have been

structurally characterized. All compounds having the respec-

tive anion bound to the Ag^Ication are monoolefinic com-

plexes,^[68]with the exception of the molecular compound

ACHTUNGTRENNUNG(triflyl)imide isoprene complex. By reacting 3 with 2.5

equivalents of isoprene in diethyl ether and subsequent

evaporation to dryness, a colorless solid was obtained. In

the proton NMR spectrum all resonances occur at slightly

lower field compared with the uncoordinated isoprene, in

which the signal of the CH proton is the most influenced

one. Whereas free isoprene reveals four signals with an inte-

gral ratio of 2:1:1:1, only three resonances are observed in

the case of the Ag^Icomplex, namely with an integral ratio

of 3:1:1. The largest values for Dd_Care found for the signals

of CH₂C_qand C_qCH, being shifted to higher field by Dd=

7.4 and 2.2 ppm, respectively. The result of the elemental

analysis suggests that the isoprene has partly been removed

upon drying of the solid in vacuum, so that the starting ma-

terial 3 might have been recovered in part. Single crystals

were grown by recrystallization of the isolated amorphous

compound from a dichloromethane solution. Although the

crystal quality was not sufficient to give reliable metric pa-

(CF₃)₂)₄}]^[69b]bearing two ethylene li-

[AgACTHUGNTERN(NGUN C₂H₄)₂{AlAHCTUNRTGEG(NNUN OCHACHTNUGTRENNGUN

gands per silver(I) ion. The ionic compounds published by

Krossing et al. incorporate one to three equivalents ethylene

per silver(I) ion.^[69]

The ethylene complexes [Cu

ACHUTNGTERN(NUG C₂H₄)AHCTUNGTREN(NUGN NTf₂)]₁(12) and [Ag-

A

CHTUNGTRENNUNG

ethylene through a 0.5m solution of 1 (CH₂Cl₂) and 3

(Et₂O), respectively.

rameters, the connectivity of [Ag₂(h²:h²-isoprene)

(11) could be determined.

N

Complex 12 was obtained from the reaction mixture at

ꢀ208C in a single-crystalline form. In the case of the Ag^I

compound 13, the solvent was nearly completely evaporated

during which time the gaseous olefin was introduced into

the ethereal solution. Upon the addition of dichlorome-

thane, dissolution of the colorless solid was observed sug-

gesting that the polymeric structure of 3 had been cracked

due to the formation of a Ag^Iethylene species. As in the

Analogous to the crystal structure of AgNTf₂(3) the two-

dimensional polymeric solid state structure of 11, which

crystallizes in the space group P1, exhibits rhombic

case of 12, single crystals of [AgACTHNUGTREN(NUG C₂H₄)₂ACHTUGNTRENN(UNG NTf₂)] (13) were

obtained from a concentrated dichloromethane solution at

ꢀ208C.

¯

Ag

N

Compared with the proton and carbon NMR spectra of

free ethylene (d_H=5.40, d_C=123.20 ppm^[38]) the ¹H NMR

spectrum of 12 shows a shift to higher field of Dd=

0.34 ppm for the signal of the olefinic protons and the

strings are interconnected by the isoprene molecules. The

atom connectivity of 11 is shown in the following schematic

diagram:

1050

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Chem. Eur. J. 2013, 19, 1042 – 1057

Copper(I) and Silver(I) Bis(trifluoromethanesulfonyl)imide

FULL PAPER

¹³C NMR signal is shifted upfield by Dd=25 ppm. In con-

in comparison to solid ethylene (1.3137 ꢃ; determined at

trast, in the case of [Cu

(C₂H₄)₃][Al(OC

(CF₃)₃)₄],^[66a]only a

85 K^[71]). The Cu C distances in 12 (2.043(2) ꢃ) are in the

ꢀ

marginal downfield shift is observed for the ethylene pro-

tons, but a significant upfield-shift occurs for the corre-

sponding carbon signal. The ¹⁹F NMR spectrum of 12 shows

(within the limits of error) the same chemical shift as ob-

served for the starting material 1. In the IR spectrum of 12

a very weak C=C stretching vibration is observed at

1544 cm^ꢀ1, which means a shift to lower frequencies by

same range as the relevant values of the one-dimensional

[70b]

ꢀ

(N N)

ꢀ

polymer [Cu

(C₂H₄)]PF₆

(N N=4-(2-pyridyl)pyri-

midine) being 2.032(5) and 2.036(6) ꢃ. The shortest contact

between two strands is found to be 2.56(4) ꢃ assigned to the

H4A-F1 interaction (S(vdW-radii)=2.9 ꢃ^[28]).

The result of a crystal structure analysis of single crystals

obtained from 12 in non-absolute NMR solvent [D₂]CH₂Cl₂

showed that the one-dimensional polymeric structure of 12

can be cracked in the presence of the s-donor water yielding

79 cm^ꢀ1

compared

to

free

ethylene

(nACTHNGUTERNN(UG C=C)=

1623 cm^ꢀ1[46,69a]). The C=C stretching vibrations of miscella-

neous transition-metal ethylene complexes are between

[CuAHCTUNERTGGN(NUN C₂H₄)ACHTUNRTEGGN(NNU H₂O)ACTHNUGTRNEN(NGU NTf₂)] (12a) (Figure 11).

ACTHNUTRGNEUNG

1493 cm^ꢀ1for [RhCp(C₂H₄)₂] and 1584 cm^ꢀ1for [Ag-

ACHTUNGTRENNUNG

of the low promotion energy and the medium electron-affin-

ity of Rh^I.^[46]Compound 12 shows a value for n

ACTHNUGRTENUNG(C=C) that is

in the middle of the range given in literature.

A section of the solid state structure of the copper(I)

compound 12 is depicted in Figure 10.

Figure 11. Molecular structure of [CuCATHUNGTNERN(NGU C₂H₄)ACHTNUTRGEG(NNUN H₂O)CAHTNUGTERNUN(GN NTf₂)] (12a).

In the molecular compound 12a, the copper atom has one

ꢀ

h²-bound ethylene molecule, one kN-coordinated NTf₂

ligand and one water molecule in its coordination sphere.

With bond angles varying from 99.6 to 132.38 the geometry

at Cu1 can be described as distorted trigonal planar. The

ꢀ

Cu1 N1 distance measures 2.050(4) ꢃ and is therefore simi-

Figure 10. Section of the crystal structure of [CuACHTNUTRGENN(GU C₂H₄)ACHTUNTGERN(NUGN NTf₂)]₁(12).

Atoms labeled (’) and (’’) are symmetry-generated.

lar to the corresponding bond lengths in [Cu

G

ACHTUNGTRENNUNG(NTf₂)]₁

(12) (2.0572(19) ꢃ), [Cu

and [Cu(CO)₂A

(h²-nbd)

ACHUTNGTRENNUG ₂ACHTUNGTRENNUNG

CTHUNGTRENNUNG

ꢀ

Compound 12 is one of the few structurally characterized

ylene ligand, the bond length of Cu1 O5 (1.966(4) ꢃ) is sig-

ꢀ

copper(I) ethylene complexes exhibiting a polymeric array

nificantly larger than in the etherate

2

(d

T

without bridging chloro ligands.^[64,70]The fact that the NTf₂

1.886(2) ꢃ). However, the Cu C_olefincontacts are with

(Cu1 C3)) and 2.028(5) ꢃ (d

almost the same as for 12 (2.043(2) ꢃ). Due to intermolecu-

lar contacts between the oxygen atoms O2, O3, and O4 of

the bisACTHNGUTERNN(UG triflyl)imide anions and the protons H5 and H6 of

the water molecules, which are far below the sum of the rel-

evant van der Waals radii (2.9 ꢃ^[28]), a hydrogen-bond net-

work is formed. In this context the following interactions

ꢀ

anion remains bound to the copper(I) ion in 12 implies that

2.021(5) ꢃ (d

G

N

the bis

G

nating counterions of copper(I), for example, Cl^ꢀ, Br^ꢀ, I^ꢀ,

and NO₃, in the presence of weak Lewis bases such as eth-

ylene.^[66b]Expectedly, the NTf₂anion is coordinated to Cu1

ꢀ

through its nitrogen atom with a Cu1 N1 bond length of

2.0572(19) ꢃ, which is comparable to those determined for

the copper(I)–NBD complex

8

(2.055(3) ꢃ) and for

are

important:

d(O2···H6)=2.35(5) ꢃ,

dACTHNGUTERNNU(G O3···H6)=

[Cu(CO)₂A

G

2.34(5) ꢃ and d

ACHTUNGTRENNUNG

than that of 2 (1.901(2) ꢃ). Moreover, there exist two strong

traces of water in olefin-paraffin gas mixtures will strongly

influence the intermolecular interaction of reversible ab-

sorbers such as CuNTf₂and AgNTf₂.

ꢀ

Cu O interactions between Cu1 and two oxygen atoms,

ꢀ

namely O1’’ and O3’’, of another NTf₂entity resulting in

the formation of linear [Cu(NTf₂-1kN:2k²O,O’)] strings

along the a axis. The relevant copper–oxygen distances

measure 2.4063(17) ꢃ and 2.0812(18) ꢃ, both being far

below the sum of the van der Waals radii of copper and

oxygen (2.9 ꢃ^[28]). Upon coordination to the copper(I) ion

the C=C bond of the h²-bound ethylene molecule is with

1.362(4) ꢃ (determined at 100(2) K) significantly elongated

In the case of the silver(I) complex 13, NMR spectroscopy

and X-ray structure analysis were applied for identification

and characterization. The sample preparation for the ele-

mental analysis failed due to loss of ethylene, which was

proven by IR spectroscopy because no C=C stretching vi-

bration was observed. The equilibrium of Equation (1) (see

below) is shifted to the side of the starting materials, if com-

Chem. Eur. J. 2013, 19, 1042 – 1057

ꢂ 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

www.chemeurj.org

1051

J. Sundermeyer et al.

plex 13 is handled in the solid state under argon and in the

absence of ethene at room temperature.

1–5 as reversible absorbers for ethylene was investigated by

NMR experiments using NMR tubes with J. Young valves

(for experimental details please refer to the Supporting In-

formation). The chemical shifts for the isolated products

(12, 13) and the in situ-generated ethylene complexes as

well as the signals observed after evaporation of the samples

are listed in Table 5.

1

With respect to the H NMR resonance of free ethylene,

the proton NMR spectrum of 13 reveals a downfield shift of

Dd=0.37 ppm, whereas an upfield shift of about Dd=

8.1 ppm is observed for d_Cindicating that an interaction be-

tween the silver(I) ion and ethylene is existing in solution.

Interestingly, the corresponding chemical shifts reported for

Table 5. Chemical shifts (in ppm) for [D₂]CH₂Cl₂solutions of free ethyl-

ene,^[38]12, 13, and the in situ-generated complexes {X+C₂H₄} (X=1–5).

Additionally, for {X+C₂H₄} the d_Hand d_Cvalues after evaporation are

listed. For d_H, only the mean value is given in each case regardless of the

signal form.

[D₂]CH₂Cl₂solutions of [Ag

(CF₃)₃)₄]^[69a]and

ACHUTGTNERN(NUG C₂H₄)₃][Al(OCACHUTNGTRENNGUN

[Ag(C₂H₄)₂{Al(OCH

N

ACHTUNGTRENNUNG

Metal

d_H

d_C

those observed for 13, suggesting that similar species are

C₂H₄, free

[Cu(C₂H₄)

1+C₂H₄

5.40

5.06

5.26

5.04

5.05

5.02

5.19

4.91

5.77

5.67

5.58^[c]

5.62

5.74^[c]

123.2

98.2

107.1

97.9

101.0

96.6

108.6

95.8

115.1

116.7

–

present in solution in each case. However, more recent

NMR data of [AgACHTUNGTRENNUNG(C₂H₄)₃][Al(OCAHCTUNGTNER(NUGN CF₃)₃)₄] acquired in the

G

E

Cu

Ag

same solvent reveal a significant deviation from the former-

ly reported ones, especially concerning d_C.^[69b]The ¹⁹F NMR

spectrum of 13 shows (within the limits of error) the same

chemical shift for the signal of the CF₃group as observed in

the case of 3.

1+C₂H₄, after evaporation^[a]

2+C₂H₄

2+C₂H₄, after evaporation

4+C₂H₄

4+C₂H₄, after evaporation

[Ag

ACHUTNGTREN(NUG C₂H₄)₂HCATUNGTRENN(UGN NTf₂)] (13)

The solid-state structure of the monomeric silver(I) com-

pound 13 is depicted in Figure 12.

3+C₂H₄

3+C₂H₄, after evaporation^[b]

5+C₂H₄

117.4

–

5+C₂H₄, after evaporation

[a] Evacuation was carried out both at room temperature and at 508C,

for 1 h in each case. [b] NMR spectra were acquired in [D₂]CH₂Cl₂/

[D₈]THF due to low solubility in [D₂]CH₂Cl₂. [c] Very weak signal inten-

sity observed.

In general, it can be stated that an upfield shift is ob-

served in the proton NMR spectra of the copper(I) ethylene

complexes with respect to free ethylene. In contrast, in the

case of the silver(I) ethylene compounds the corresponding

signal is deshielded. For both the Cu^Iand Ag^Iethylene spe-

cies, only one somewhat broadened or slightly textured reso-

nance occurs for the ethylene protons, suggesting coales-

cence of the signals for coordinated and free ethylene.

Therefore, we tried to record a proton NMR spectrum of

{3+C₂H₄} (see Table 5) at 193 K. Yet, we failed, presumably

due to the lowered solubility of the complex as no signal

corresponding to ethylene was present in the received NMR

spectrum. Similar results were reported by the group of

Krossing on their silver aluminates.^[69b]

Figure 12. Molecular structure of [AgACHTNUGTRENN(UG C₂H₄)₂ACHTUGNTERN(NUGN NTf₂)] (13).

The silver atom in complex 13 is essentially trigonally

ꢀ

planar coordinated through the nitrogen atom of the NTf₂

2

ꢀ

ligand and two h -bound ethylene molecules. The Ag1 N1

bond length (2.343(2) ꢃ) is in the expected range.^[72]More-

over, there exist two intermolecular Ag···O contacts below

the sum of the relevant van der Waals radii (3.2 ꢃ^[28]), one

above and one below the (C3-C4)_centroid-Ag1-N1 plane, with

a minimum distance of 2.8509(18) ꢃ. Upon coordination of

ethylene to silver(I) an elongation of the C=C bond

(1.332(5) ꢃ; determined at 100(2) K) is observed compared

to crystalline ethylene (1.3137 ꢃ; 85 K^[71]), which is expect-

edly smaller than in the case of the copper(I) ethylene com-

plex 12. In comparison with 13, slightly larger C=C bond

lengths of 1.344(3) and 1.345(3) ꢃ (determined at 100 K)

With respect to free ethylene, both the Cu^Iethylene spe-

cies and the Ag^Iethylene complexes show an upfield shift

by several ppm for the ¹³C NMR resonance frequency of the

olefinic carbon atoms; the shifts are more significant in the

case of copper(I).

Upon evacuation of the samples d_Hof the ethylene moiet-

ies is, in most cases, only marginally influenced, regardless

of the metal. In the case of the silver(I) ethylene complexes

the olefin seems to be entirely removed in vacuo as can be

(CF₃)₂)₄}].^[69b]Accordingly,

are found in [AgACHTUNGTRENNUNG(C₂H₄)₂{AlACHTUNRTGEG(NNNU OCHACHTUNGTRENNGUN

ꢀ

the Ag C distances determined for the latter compound

ranging from 2.355(2) to 2.413(2) ꢃ are shorter than those

of 13 (2.413(3)–2.431(3) ꢃ).

1

seen from the very weak ethylene signals in the H NMR

spectra and the absence of the corresponding signals in the

¹³C NMR spectra. After evacuation of the Cu^I-containing

samples, a further shift to higher field is observed for the

NMR studies concerning the stability of in situ generated

Cu^Iand Ag^Iethylene species: The potential of compounds

1052

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ꢂ 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Chem. Eur. J. 2013, 19, 1042 – 1057

Copper(I) and Silver(I) Bis(trifluoromethanesulfonyl)imide

FULL PAPER

¹³C NMR resonances assigned to the ethylene moieties.

Moreover, the carbon NMR spectra of these samples show

chemical shifts that are rather in the range of that found for

isolated 12. There exist two possible interpretations for

these findings: On the one hand, it might be assumed that

d_Cobserved for the in situ-prepared copper(I) ethylene

complexes are averaged values. In other words, the

¹³C NMR resonances of free ethylene and of the in situ-gen-

erated complexes, probably similar to 12, coalesce (see

above). As a consequence, only excess ethylene would have

been removed upon evaporation of the Cu^I-containing sam-

ples. One the other hand, the shift to higher field should in-

crease with a decreasing number of olefinic ligands coordi-

nated to the copper(I) ion, namely due to the enhancement

of the metal–olefin interaction. Thus, it is suggested that in

ethylene-saturated solutions of {X+C₂H₄} (X=1, 2, 4;

Table 5) more than one ethylene molecule interacts with the

ACHTUNGTRENNUNG

ꢀ

the NTf₂anion is not weakly coordinating, but serves as

ligand. As expected, in all cases strong bonds through the

nitrogen atom of the NTf₂anion are observed. In addition,

in most cases the oxygen atoms of the bisACTHNUTRGNEUNG(triflyl)imide take

part in secondary interactions with the relevant coinage

metal ions.

ꢀ

Experimental Section

Specifications of the equipment and methods used for characterization

and the preparation of staring materials are given in the Supporting In-

formation. CCDC-876577 (1), CCDC-876578 (2), CCDC-876579 (3),

CCDC-876580 (4), CCDC-876581 (6), CCDC-876582 (7), CCDC-876583

(8), CCDC-876584 (9), CCDC-876585 (10), CCDC-876586 (12), CCDC-

876587 (12a), and CCDC-876588 (13) contain the supplementary crystal-

lographic data for this paper. These data can be obtained free of charge

from The Cambridge Crystallographic Data Centre via www.ccdc.cam.a-

c.uk/data_request/cif.

ACTHNUTRGNEUNG

Cu^Iion, so that even cationic species such as [Cu(C₂H₄)_n]⁺

(n=2, 3) might be present. In this context it is worth men-

tioning that Krossing and co-workers also reported that the

[Cu

ACHUTGTNNERNUG(MesH)₂][CuACHTGNUTRENNUNG

ACTHNUTRGNEUNG

upfield shift of the ¹³C NMR signal of [Ag(C₂H₄)_n]⁺(n=1–

in CH₂Cl₂(20 mL) was added to a Schlenk flask charged with [CuACHTUNGTRENNUNG

3) is not only dependent on the number of ligands, but also

found to be larger in the case of molecular species.^[69b]

In summary, the silver(I)-containing compounds 3 and 5,

as well as the chemically more sensitive copper(I) bis-

(1.83 g, 2.00 mmol). Instantly, boiling of the solvent was observed, accom-

panied by a color change of the reaction mixture from red/yellow to col-

orless. The reaction mixture was filtered by using a syringe filter and the

solvent was removed in vacuo yielding 1 (4.42 g, 95%) as fine crystalline

colorless solid. ¹H NMR (250.1 MHz, [D₂]CH₂Cl₂): d=2.32–2.52 (m,

18H; CH₃), 6.97–7.15 ppm (m, 6H; CH); ¹³C NMR (62.9 MHz,

ACHTUNGTRENNUNG(triflyl)imides 1, 2, and 4, can serve as ethylene absorbers.

However, in the case of the copper(I) compounds, higher

temperatures may be required for ethylene desorption. An

application of the well-characterized IL 5 in membrane-

based processes might be the most promising perspective.

[D₂]CH₂Cl₂): d=21.2 (CH₃), 119.6 (q, ¹J

ACHTNGUTERNNU(G C,F)=323 Hz; CF₃), 121.3

(CH), 136.2 ppm (CCH₃); ¹⁹F NMR (282.4 MHz, [D₂]CH₂Cl₂): d=ꢀ74.8

(CF₃) ppm; IR (neat): n˜ =3054 (vw), 2965 (vw), 2931 (vw), 2864 (vw),

1816 (vw), 1590 (w), 1573 (w), 1500 (vw), 1464 (w), 1388 (s), 1376 (s),

1323 (w), 1299 (w), 1217 (s), 1194 (vs), 1130 (vs), 1039 (m), 1022 (m), 967

(vs), 861 (m), 839 (m), 765 (w), 690 (w), 660 (m), 606 (vs), 566 (vs), 534

(w), 507 cm^ꢀ1(vs); APCI-MS (negative mode): m/z (%) calcd for

C₂F₆NO₄S₂: 279.9178; found: 279.9171 [NTf₂]^ꢀ(35); calcd for

C₂ClF₆NNaO₄S₂: 337.8765; found: 337.8755 [NTf₂+NaCl]^ꢀ(100), 416

(16); elemental analysis calcd (%) for C₂₂H₂₄Cu₂F₁₂N₂O₈S₄

(927.78 gmol^ꢀ1): C 28.48, H 2.61, N 3.02; found: C 28.08, H 2.42, N 3.34.

Single crystals of 1 were obtained from CH₂Cl₂at ꢀ208C.

Conclusion

Herein, we have presented the first comprehensive and

comparative reactivity and structural study of silver(I)

versus copper(I) bistriflylimides regarding their reactions

with the ionic liquid [emim]NTf₂, the arene 1,3,5-trimethyl-

benzene, and diverse olefins. Whereas pure and crystalline

[CuNTf₂]₁is unknown, we managed to fully characterize

two solvent adducts with rather weakly bonded and inert li-

[CuACTHNUTGRENN(UG Et₂O)ACHTUTGNREN(NGUN NTf₂)] (2): Complex 2 was prepared by dissolving 1 (2.25 g,

2.43 mmol) in Et₂O (25 mL) and storing the solution at ꢀ308C overnight.

The solvent was removed through a syringe at ꢀ358C and the crystalline

colorless solid was washed with cold ether. After removal of the solvent

the solid was dried under vacuum to give 2 (1.12 g, 55%) as colorless

needles. ¹H NMR (300.1 MHz, [D₂]CH₂Cl₂): d=1.46 (t, ³J

6H; CH₃), 3.87 ppm (q, ³J

(62.9 MHz, [D₂]CH₂Cl₂): d=16.2 (CH₃), 72.5 (CH₂), 119.7 ppm (q,

¹J(C,F)=322 Hz; CF₃); ¹⁹F NMR (282.4 MHz, [D₂]CH₂Cl₂): d=

ACHTUNGTRENNUNG

(h³-MesH)₂][Cu-

ACHTUNGTRENNUNG

AHCTUNGTRENNUNG

gands, namely the sandwich complex [Cu

(NTf₂)₂] (1) and the etherate [Cu(Et₂O)(NTf₂)] (2). Further-

A

R

ACHTUNGTRENNUNG

AHCTUNGTRENNUNG

more, we determined the layer structure of crystalline

[AgNTf₂]₁(3), a technologically interesting compound that

is nearly insoluble in non- or weakly-coordinating solvents

such as dichloromethane but soluble in coordinating sol-

vents like diethyl ether or in olefins.

ꢀ75.1 ppm (CF₃); IR (neat): n˜ =2981 (w), 2955 (vw), 2937 (vw), 2909

(w), 2876 (vw), 1813 (vw), 1490 (vw), 1458 (w), 1448 (w), 1378 (s), 1365

(s), 1301 (w), 1235 (m), 1195 (vs), 1150 (m), 1124 (s), 1085 (m), 1049 (m),

1038 (m), 970 (vs), 926 (m), 850 (m), 834 (m), 763 (w), 656 (m), 601 (vs),

567 (vs), 534 (m), 508 cm^ꢀ1(vs); APCI-MS (negative mode): m/z (%)

calcd for C₂F₆NO₄S₂: 279.9178; found: 279.9172 [NTf₂]^ꢀ(35); calcd for

C₂ClF₆NNaO₄S₂: 337.8765; found: 337.8756 [NTf₂+NaCl]^ꢀ(100); ele-

mental analysis calcd (%) for C₆H₁₀CuF₆NO₅S₂(417.82 gmol^ꢀ1): C 17.25,

H 2.41, N 3.45; found: C 17.12, H 2.32, N 3.62. Single crystals of 2 were

grown from Et₂O at ꢀ208C. Complex 2 shows disproportionation in

MeOH, that is, formation of elemental copper is observed.

Purging solutions of 1 and 3 with excess ethylene yielded

[Cu

form of single crystals. Additionally, the two new complexes

[emim][M(NTf₂)₂] (M=Cu 4, Ag 5) were tested as potential

ACHTUNGTRENNUNG(C₂H₄)ACHTUNGTRENNUNG(NTf₂)]₁(12) and [AgAHCTUNGERTG(NUNN C₂H₄)₂ACHTNUGTERN(NGUN NTf₂)] (13) in the

ACHTUNGTRENNUNG

chemisorbers for ethylene. The silver(I) containing com-

pounds 3 and 5 proved to be reversible ethylene absorbers

at room temperature.

A large structural diversity was found within the herein

presented crystal structures incorporating the bis-

AgNTf₂(3): Silver(I) bis(trifluoromethanesulfonyl)imide was prepared

by two different methods.

Method A:^[9]

(230 mL) was added dropwise to

91.54 mmol) in water (275 mL). The precipitate was collected by filtra-

A

solution of NaOH (5.49 g, 137.25 mmol) in water

solution of AgNO₃(15.55 g,

a

Chem. Eur. J. 2013, 19, 1042 – 1057

ꢂ 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

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1053

J. Sundermeyer et al.

tion and washed with water until the washings were pH neutral. A solu-

tion of HNTf₂(18.00 g, 64.02 mmol) in water (260 mL) was added. The

reaction mixture was stirred overnight at ambient temperature. The un-

reacted silver salt was filtered off and the water was removed at the

rotary evaporator. The colorless solid was recrystallized from CH₂Cl₂and

dried in vacuo to yield AgNTf₂(12.83 g, 52%).

83 (40), calcd for Ag: 106.9045; found: 106.9046 [Ag]⁺(39); calcd for

Ag: 111.0917; found: 111.0917 (100) [emim]⁺; (m/z calcd for C₆H₁₁N₂:

111.0917), 148 (26), 188 (89); APCI-MS (negative mode): m/z (%) calcd

for C₂F₆NO₄S₂: 279.9178; found: 279.9180 [NTf₂]^ꢀ(89); calcd for

C₄F₁₂N₂NaO₈S₄: 582.8249; found: 582.8255 [2ꢄNTf₂+Na]^ꢀ(56); calcd

for C₄F₁₂KN₂O₈S₄: 598.7988; found: 598.7995 [2ꢄNTf₂+K]^ꢀ(53); calcd

for C₄AgF₁₂N₂O₈S₄: 668.7383; found: 668.7395 [AgACTHNUTRGNEUNG

(NTf₂)₂]^ꢀ(100); ele-

Method B: A solution of HNTf₂(141 mg, 0.50 mmol) in CH₂Cl₂(4 mL)

was added to [AgACHTUNGTRENNUNG(Mes)]₄(114 mg, 0.13 mmol). During the addition the

mental analysis calcd (%) for C₁₀H₁₁AgF₁₂N₄O₈S₄(779.33 gmol^ꢀ1): C

15.41, H 1.42, N 7.19, S 16.46; found: C 15.84, H 1.55, N 7.46, S 16.54.

color of the reaction mixture changed from yellow to colorless. After stir-

ring overnight at ambient temperature the solution was filtered via a sy-

ringe filter and the solvent was removed under vacuum to give 3 in good

yield (145 mg, 75%). ¹³C NMR (62.9 MHz, [D₂]CH₂Cl₂/[D₈]THF (11:1)):

[CuACHTUNGRTNEUNG(cod)₂]NTf₂(6): COD (0.3 mL, 270 mg, 2.50 mmol) was added to a

solution of 2 (417 mg, 1.00 mmol) in CH₂Cl₂(2 mL). Meanwhile, boiling

of the solvent was observed. Stirring was continued for 1 h at room tem-

perature. When covering the colorless solution with a layer of n-hexane

(1 mL) a colorless crystalline solid precipitated instantly. The supernatant

solution was removed by using a syringe and the solid was dried under

vacuum yielding 6 (476 mg, 85%). ¹H NMR (300.1 MHz, [D₂]CH₂Cl₂):

d=24.9 ([D₈]THF), 67.8 ([D₈]THF), 120.2 ppm (q, ¹J

ACTHNUGRTENUNG(C,F)=322 Hz;

CF₃); ¹⁹F NMR (282.4 MHz, [D₂]CH₂Cl₂/[D₈]THF (11:1)): d=ꢀ75.7 ppm

(CF₃); ¹⁹F NMR (282.4 MHz, [D₂]CH₂Cl₂): d=ꢀ74.8 (CF₃) ppm; IR

(neat): n˜ =1758 (vw), 1329 (m), 1306 (m), 1196 (vs), 1098 (vs), 1020 (vs),

822 (w), 791 (s), 771 (w), 732 (s), 636 (m), 582 (vs), 567 (vs), 533 (m), 502

(vs), 425 (m), 403 cm^ꢀ1(w); APCI-MS (positive mode): m/z (%): calcd

for Ag: 106.9045; found: 106.9044 [Ag]⁺(100), 123 (26), 132 (19), 139

(91), 148 (70), 155 (14), 164 (12), 171 (78), 180 (73), 189 (45), 416 (43),

425 (32), 434 (13); APCI-MS (negative mode): m/z (%): calcd for

C₂F₆NO₄S₂: 279.9178; found: 279.9172 [NTf₂]^ꢀ(100); calcd for

C₂ClF₆NNaO₄S₂: 337.8765; found: 337.8758 [NTf₂+NaCl]^ꢀ(47), 422

(65), 424 (85); elemental analysis calcd (%) for C₂AgF₆NO₄S₂

(388.02 gmol^ꢀ1): C 6.19, H 0.00, N 3.61, S 16.53; found: C 6.54, H 0.00, N

3.97, S 16.74. Single crystals of 3 were obtained from CH₂Cl₂at ꢀ208C

d=2.53 (brs, 16H; CH₂), 5.75–6.10 ppm (m, 8H; CH); ¹³C NMR

1

(62.9 MHz, [D₂]CH₂Cl₂): d=28.3 (CH₂), 120.3 (q, J

N

123.3 ppm (CH); ¹⁹F NMR (282.4 MHz, [D₂]CH₂Cl₂): d=ꢀ77.8 ppm

(CF₃); IR (neat): n˜ =3038 (vw), 3010 (w), 2958 (w), 2901 (m), 2846 (w),

1841 (w), 1791 (w), 1591 (w), 1486 (m), 1452 (w), 1432 (m), 1394 (vw),

1355 (s), 1335 (s), 1238 (m), 1180 (vs), 1164 (vs), 1134 (vs), 1083 (m),

1045 (s), 1032 (s), 1001 (m), 988 (m), 907 (m), 872 (m), 852 (m), 825 (m),

791 (m), 761 (s), 735 (m), 683 (vw), 664 (m), 610 (vs), 566 (s), 510 (s),

406 cm^ꢀ1(m); ESI-MS (negative mode): m/z (%) calcd for C₂F₆NO₄S₂

279.9178; found: 279.9174 [NTf₂]^ꢀ(100); calcd for C₄F₁₂N₂NaO₈S₄:

when attempting to crystallize [emim][Ag

G

3

582.8249;

found:

582.8233

[2ꢄNTf₂+Na]^ꢀ

(18);

calcd

for

shows disproportionation in MeOH, that is, formation of elemental silver

is observed.

C₆F₁₈N₃Na₂O₁₂S₆: 885.7320; found: 885.7296 [3ꢄNTf₂+2ꢄNa]^ꢀ(3); ele-

mental analysis calcd (%) for C₁₈H₂₄CuF₆NO₄S₂(560.06 gmol^ꢀ1): C 38.60,

H 4.32, N 2.50, S 11.45; found: C 38.62, H 4.30, N 2.52, S 11.58. Single

crystals of 6 were grown from CH₂Cl₂/n-hexane at room temperature.

Complex 6 was also yielded by applying the same procedure, but using 1

as Cu^Istarting material.

ACHTUNGTRENNUNG[emim][CuACHTUNGTRENNUNG(NTf₂)₂] (4): CH₂Cl₂(5 mL) was added to a mixture of 2

(106 mg, 0.25 mmol) and [emim]NTf₂(99 mg, 0.25 mmol). After the reac-

tion mixture had been stirred at room temperature for 1 h, the solvent

was removed in vacuo and the colorless solid was dried under vacuum to

give

4

(184 mg, 100%). M.p. 668C (decomp 3658C); ¹H NMR

[AgACHTUGNETRN(NUG cod)₂]NTf₂(7): COD (0.3 mL, 287 mg, 2.65 mmol) was added to an

(250.1 MHz, [D₂]CH₂Cl₂): d=1.56 (t, ³J

A

ethereal solution (2.5 mL Et₂O) of 3 (412 mg, 1.06 mmol). Instantly, boil-

ing of the solvent was observed and a crystalline precipitate was ob-

tained. The supernatant liquid was removed by decantation and the solid

was dried in vacuo to yield 7 as colorless solid. ¹H NMR (250.1 MHz,

[D₂]CH₂Cl₂): d=2.37–2.65 (m, 16H; CH₂), 5.95–6.22 ppm (m, 8H; CH);

3

3.91 (s, 3H; CH₃), 4.21 (q, J

(H,H)=7.4 Hz, 2H; CH₂CH₃), 7.18–7.40 (m,

2H; CH

[D₂]CH₂Cl₂): d=15.3 (CH₂CH₃), 37.0 (CH₂CH₃), 46.1 (CH₃), 119.7 (q,

¹J

(C,F)=323 Hz; CF₃), 122.7 (CH(4,5)), 124.4 (CH(4,5)), 134.8 ppm

ACHTUNGTRENNUNG

(4,5)), 8.26 ppm (brs, 1H; CH(2)); ¹³C NMR (62.9 MHz,

G

A

ACHTUNGTRENNUNG

(CH(2)); ¹⁹F NMR (282.4 MHz, [D₂]CH₂Cl₂): d=ꢀ75.2 ppm (CF₃); IR

(neat): n˜ =3164 (w), 3110 (w), 3000 (vw), 2962 (w), 1814 (vw), 1608 (w),

1568 (m), 1472 (vw), 1454 (vw), 1427 (vw), 1389 (s), 1372 (m), 1339 (m),

1323 (w), 1300 (vw), 1260 (m), 1192 (vs), 1167 (s), 1123 (vs), 1031 (m),

1022 (m), 965 (vs), 840 (s), 802 (m), 765 (m), 745 (m), 703 (m), 658 (m),

601 (vs), 567 (vs), 536 (m), 508 (vs), 433 (m), 422 cm^ꢀ1(m); ESI-MS (pos-

itive mode): m/z calcd (%) for C₆H₁₁N₂: 111.0917; found: 111.0915

[emim]⁺(100); APCI-MS (negative mode): m/z calcd (%) for

C₂F₆NO₄S₂: 279.9178; found: 279.9174 [NTf₂]^ꢀ(44); calcd for

C₂ClF₆NNaO₄S₂: 337.8765; found: 337.8759 [NTf₂+NaCl]^ꢀ(100); ele-

mental analysis calcd (%) for C₁₀H₁₁CuF₁₂N₄O₈S₄(735.01 gmol^ꢀ1): C

16.34, H 1.51, N 7.62; found: C 16.65, H 1.73, N 7.89. Single crystals of 4

were grown from CH₂Cl₂at ꢀ208C.

¹³C NMR (62.9 MHz, [D₂]CH₂Cl₂): d=28.3 (CH₂), 120.3 (q, ¹J

ACHTUNGTRENNUNG(C,F)=

322 Hz; CF₃), 126.8 ppm (CH); ¹⁹F NMR (282.4 MHz, [D₂]CH₂Cl₂): d=

ꢀ77.4 ppm (CF₃); IR (neat): n˜ =3032 (vw), 3003 (vw), 2959 (w), 2935

(w), 2900 (w), 2845 (w), 1839 (vw), 1790 (vw), 1602 (w), 1488 (m), 1452

(w), 1430 (m), 1395 (vw), 1354 (s), 1337 (s), 1296 (w), 1262 (m), 1239

(m), 1165 (vs), 1135 (vs), 1084 (m), 1045 (vs), 1031 (vs), 986 (m), 909

(m), 883 (w), 845 (m), 821 (s), 792 (m), 749 (s), 739 (m), 725 (m), 674

(w), 660 (m), 610 (vs), 566 (vs), 510 (s), 436 cm^ꢀ1(w); APCI-MS (nega-

tive mode): m/z (%): 227 (28), calcd for C₂F₆NO₄S₂: 279.9178; found:

279.9180 (31) [NTf₂]^ꢀ; 338 [NTf₂+NaCl]^ꢀ(92), 416 (67); elemental anal-

ysis calcd (%) for C₁₈H₂₄AgF₆NO₄S₂(604.39 gmol^ꢀ1): C 35.77, H 4.00, N

2.32; found: C 35.43, H 3.98, N 2.65. Single crystals of 7 were obtained

from CH₂Cl₂/n-hexane at ambient temperature.

A

U

[CuACHTGUNTRENNUG ₂CAHTUNGTNER(NUNG NTf₂)] (8): NBD (0.2 mL, 182 mg, 1.98 mmol) was added to

(h²-nbd)

3

a solution of 2 (320 mg, 0.77 mmol) in CH₂Cl₂(1.5 mL). A colorless crys-

talline solid precipitated from the reaction mixture at room temperature

overnight. The supernatant solution was removed via a syringe and the

obtained solid was dried under vacuum yielding 8 in the form of a color-

0.53 mmol). After the reaction mixture had been stirred at ambient tem-

perature for 1 h, the solvent was removed in vacuo and the colorless, vis-

cous residue was dried by freeze-drying to give 5 (410 mg, 99%). Glass

transition ꢀ508C; m.p. 218C (decomp 3928C); ¹H NMR (250.1 MHz,

less solid. ¹H NMR (300.1 MHz, [D₂]CH₂Cl₂): d=2.00 (t, ³J

ACHTUNGTRENNUNG

[D₂]CH₂Cl₂): d=1.55 (t, ³J

G

1.5 Hz, 4H; CH₂), 3.86 (sept, ^3,4J

³J

ACHTUNGTRENNUNG

CH₃), 4.21 (q, ³J

1.8 Hz, 2H; CH

(H,H)=7.4 Hz, 2H; CH₂CH₃), 7.27 (pt, ^3,4J

G

ACHTUNGTRENNUNG

N

ACHTUNGTRENNUNG

(CH_olef); ¹⁹F NMR (282.4 MHz, [D₂]CH₂Cl₂): d=ꢀ74.6 ppm (CF₃); IR

(neat): n˜ =3493 (vw), 3083 (vw), 3063 (vw), 3027 (w), 2990 (w), 2927 (m),

2864 (m), 1781 (vw), 1597 (vw), 1561 (w), 1481 (vw), 1457 (m), 1384 (s),

1364 (m), 1312 (m), 1272 (w), 1234 (m), 1192 (vs), 1128 (vs), 1010 (m),

964 (vs), 941 (m), 882 (m), 850 (m), 813 (m), 801 (s), 793 (s), 772 (m),

756 (m), 710 (m), 689 (vs), 649 (m), 612 (vs), 566 (vs), 540 (m), 507 (vs),

471 (m), 433 (m), 421 cm^ꢀ1(m); APCI-MS (negative mode): m/z (%)

G

E

ACHTUNGTRENNUNG

(CH(2)); ¹⁹F NMR (282.4 MHz, [D₂]CH₂Cl₂): d=ꢀ76.1 ppm (CF₃); IR

(neat): n˜ =3162 (w), 3123 (vw), 2990 (vw), 1572 (w), 1471 (vw), 1457

(vw), 1431 (vw), 1370 (m), 1350 (m), 1181 (vs), 1124 (vs), 1058 (m), 998

(vs), 840 (w), 791 (m), 743 (m), 702 (w), 649 (m), 609 (vs), 595 (s), 568

(s), 533 (w), 508 (s), 403 cm^ꢀ1(vw); ESI-MS (positive mode): m/z (%):

1054

www.chemeurj.org

ꢂ 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Chem. Eur. J. 2013, 19, 1042 – 1057

Copper(I) and Silver(I) Bis(trifluoromethanesulfonyl)imide

FULL PAPER

calcd for C₂F₆NO₄S₂: 279.9181; found 279.9178 [NTf₂]^ꢀ(34); calcd for

C₂ClF₆NNaO₄S₂: 337.8765; found: 337.8765 [NTf₂+NaCl]^ꢀ(100); 416

(16); elemental analysis calcd (%) for C₁₆H₁₆CuF₆NO₄S₂(527.98 gmol^ꢀ1):

C 36.40, H 3.05, N 2.65; found: C 36.04, H 2.94, N 2.57. Single crystals of

8 were grown from CH₂Cl₂at room temperature. Complex 8 was also

prepared by applying a 0.5m solution (with respect to copper) of 1 in

CH₂Cl₂, at which 1 and NBD were employed in a molar ratio of 1:5.

After covering the reaction mixture with a layer of n-hexane, 8 was iso-

lated by decanting the supernatant solution and dried in vacuo.

1306 (w), 1285 (w), 1191 (vs), 1112 (vs), 1060 (m), 980 (s), 963 (vs), 836

(w), 819 (m), 794 (m), 770 (w), 750 (m), 701 (vw), 660 (m), 588 (vs), 568

(vs), 533 (m), 501 (vs), 420 cm^ꢀ1(m); APCI-MS (negative mode): m/z

calcd (%) for C₂F₆NO₄S₂: 279.9178; found: 279.9178 [NTf₂]^ꢀ(21); ele-

mental analysis calcd (%) for C₄H₄CuF₆NO₄S₂(371.75 gmol^ꢀ1): C 12.92,

H 1.08, N 3.77; found: C 12.59, H 1.06, N 4.04. Applying a 0.5m solution

(with respect to copper) of 2 in CH₂Cl₂yielded a pale purple solution

from which 12 could not be isolated. Single crystals of 12 deliquesce

when exposed to a stream of ethylene. However, after a short time,

excess ethylene is released and 12 recrystallizes.

ACHTUNGTRENNUNG ACHTUNGTRENNUNG(NTf₂)₂]₁(9): NBD (0.03 mL, 23 mg, 0.25 mmol) was

[Cu₂(h²:h²-nbd)

[AgACTHNUTRGENNG(U C₂H₄)₂ACHTUGNTREN(NUGN NTf₂)] (13): A stream of ethylene was introduced into a solu-

added to a solution of 1 (232 mg, 0.25 mmol) in CH₂Cl₂(1 mL). Instantly,

a colorless solid precipitated and the supernatant solution was decanted.

The solid was washed with CH₂Cl₂three times and dried under vacuum

to give 9 (164 mg, 84%). ¹H NMR (250.1 MHz, [D₂]CH₂Cl₂): d=2.03

(brs, 2H; CH₂), 3.86–3.92 (m, 2H; CH), 6.36 ppm (brs, 4H; CH_olef);

¹⁹F NMR (282.4 MHz, [D₂]CH₂Cl₂): d=ꢀ74.6 ppm (CF₃); IR (neat): n˜ =

3504 (w), 3493 (w), 2943 (vw), 1600 (vw), 1471 (vw), 1456 (vw), 1387 (s),

1353 (m), 1344 (m), 1327 (m), 1303 (m), 1285 (w), 1208 (s), 1193 (vs),

1129 (m), 1120 (m), 1104 (s), 1061 (m), 989 (vs), 921 (m), 895 (w), 859

(w), 811 (m), 789 (m), 759 (m), 664 (m), 646 (m), 607 (vs), 594 (s), 569

(s), 540 (m), 507 (vs), 415 cm^ꢀ1(m); ESI-MS (negative mode): m/z (%)

calcd for C₂F₆NO₄S₂: 279.9178; found: 279.9181 [NTf₂]^ꢀ(49); calcd for

C₂ClF₆NNaO₄S₂: 337.8765; found: 337.8766 [NTf₂+NaCl]^ꢀ(100); 416

(17); elemental analysis calcd (%) for C₁₁H₈Cu₂F₁₂N₂O₈S₄

(779.53 gmol^ꢀ1): C 16.95, H 1.03, N 3.59, S 16.45; found: C 16.88, H 1.42,

N 3.88, S 16.75.

tion of 3 (194 mg, 0.50 mmol) in Et₂O (1 mL) at ambient temperature for

about 30 s. The diethyl ether was almost quantitatively evaporated by

passing the gaseous olefin through. Upon addition of CH₂Cl₂(1 mL) a

colorless solution was obtained, from which 13 precipitated at ꢀ208C as

colorless single crystals. ¹H NMR (250.1 MHz, [D₂]CH₂Cl₂): d=5.77 ppm

(brs, 8H; CH); ¹³C NMR (62.9 MHz, [D₂]CH₂Cl₂): d=115.1 (CH),

120.0 ppm (q, ¹J

(C,F)=322 Hz; CF₃); ¹⁹F NMR (282.4 MHz,

ACHTUNGTRENNUNG

[D₂]CH₂Cl₂): d=ꢀ74.8 ppm (CF₃).

Acknowledgements

This work was partially supported by the DFG priority program SPP

1191 “Ionic Liquids”. We gratefully acknowledge Dipl.-Chem. Ilka

Paulus (working group of Prof. Dr. Andreas Greiner) for her kind assis-

tance concerning the thermoanalytical characterization.

[Ag(h²:h²-nbd)

ACHTUNGTRENNUNG(NTf₂)]₁(10): NBD (0.3 mL, 230 mg, 2.50 mmol) was

added to an ethereal solution (2 mL Et₂O) of 3 (388 mg, 1.00 mmol).

Almost instantly, a colorless crystalline solid precipitated. All volatile

components were removed in vacuo yielding 10. ¹H NMR (250.1 MHz,

[D₂]CH₂Cl₂): d=2.14 (t, ³J

^3,4J(H,H)=1.8 Hz, 2H; CH), 7.30 ppm (t, ³J

¹³C NMR (62.9 MHz, [D₂]CH₂Cl₂): d=51.9 (CH), 77.9 (CH₂), 120.0 (q,

¹J(C,F)=323 Hz; CF₃), 144.5 ppm (CH_olef); ¹⁹F NMR (282.4 MHz,

ACHTUNGTRENNUNG

[1] a) S. H. Strauss, O. G. Polyakov, J. W. Hammel, S. M. Ivanova, S. V.

Ivanov, M. D. Havighurst, US 6,114,266A, 2000; b) O. G. Polyakov,

S. M. Ivanova, C. M. Gaudinski, S. M. Miller, O. P. Anderson, S. H.

Strauss, Organometallics 1999 , 18 , 376 9 –3 771.

[2] A. Vij, Y. Y. Zheng, R. L. Kirchmeier, J. M. Shreeve, Inorg. Chem.

1994 , 33 , 328 1 –3 288.

[3] a) N. R. Brooks, S. Schaltin, K. Van Hecke, L. Van Meervelt, K. Bin-

nemans, J. Fransaer, Chem. Eur. J. 2011 , 17 , 505 4 –5 059; b) K. Bin-

nemans, N. R. Brooks, J. Fransaer, S. Schaltin, WO 2011/109 878A1,

2011; c) S. Schaltin, N. R. Brooks, L. Stappers, K. Van Hecke, L. Van

Meervelt, K. Binnemans, J. Fransaer, Phys. Chem. Chem. Phys.

2012 , 14 , 170 6 –1 715.

[4] C. Fehr, M. Vuagnoux, A. Buzas, J. Arpagaus, H. Sommer, Chem.

Eur. J. 2011 , 17 , 621 4 –6 220.

[5] M. Stricker, T. Linder, B. Oelkers, J. Sundermeyer, Green Chem.

2010 , 12 , 158 9 –1 598.

[6] J. Sundermeyer, M. Stricker, P. Wasserscheid, B. U. Melcher, M.

Haumann, DE 10 2010 036 631A1, 2012; WO 2012/013606A1 2012.

[7] E. I. Rogers, D. S. Silvester, S. E. Ward Jones, L. Aldous, C. Harda-

cre, A. J. Russell, S. G. Davies, R. G. Compton, J. Phys. Chem. C

2007 , 111 , 1395 7 –1 3966.

A

ACHTUNGTRENNUNG

[D₂]CH₂Cl₂): d=ꢀ74.9 ppm (CF₃); IR (neat): n˜ =3093 (vw), 3068 (vw),

3023 (vw), 2961 (vw), 2926 (vw), 2856 (vw), 1658 (vw), 1521 (vw), 1485

(w), 1460 (w), 1366 (m), 1355 (m), 1343 (m), 1329 (m), 1311 (m), 1261

(w), 1238 (m), 1182 (vs), 1127 (s), 1056 (m), 1009 (s), 980 (m), 953 (m),

926 (m), 887 (m), 791 (m), 771 (m), 731 (m), 670 (m), 634 (m), 608 (vs),

568 (s), 511 (s), 432 (m), 406 cm^ꢀ1(m); APCI-MS (negative mode): m/z

(%) calcd for C₂F₆NO₄S₂: 279.9178; found: 279.9180 [NTf₂]^ꢀ(36); calcd

for C₂ClF₆NNaO₄S₂: 337.8765; found: 337.8766 [NTf₂+NaCl]^ꢀ; 416 (14);

elemental analysis calcd (%) for C₂₇H₂₄Ag₃F₁₈N₃O₁₂S₆(1440.48 gmol^ꢀ1):

C 22.51, H 1.68, N 2.92, S 13.36; found: C 22.76, H 1.83, N 3.10, S 13.22.

Single crystals of 10 were obtained from Et₂O at ambient temperature.

A

E

(11):

Isoprene

(0.3 mL,

170 mg,

2.50 mmol) was added to a solution of 3 (196 mg, 0.51 mmol) in Et₂O

(2 mL). After stirring overnight the reaction mixture was filtered through

a syringe filter and the filtrate was evaporated to dryness. The colorless

solid was dried by freeze-drying. ¹H NMR (250.1 MHz, [D₂]CH₂Cl₂): d=

2.02 (brs, 3H; CH₃), 5.34–5.43 (m, 3H; C_qCH₂, CHCH₂), 5.46 (brs, 1H;

CHCH₂), 6.92 ppm (dd, ³J

(62.9 MHz, [D₂]CH₂Cl₂): d=18.3 (CH₃), 106.5 (C_qCH₂), 117.1 (CHCH₂),

120.0 (q, ¹J

(C,F)=322 Hz; CF₃), 137.8 (CHCH₂), 143.4 ppm (C_q);

(H,H)=10.0, 17.1 Hz, 1H; CH); ¹³C NMR

ACHTUNGTRENNUNG

[8] N. Serizawa, Y. Katayama, T. Miura, Electrochim. Acta 2010 , 56 ,

34 6 –3 51.

[9] F. Agel, F. Pitsch, F. F. Krull, P. Schulz, M. Wessling, T. Melin, P.

Wasserscheid, Phys. Chem. Chem. Phys. 2011 , 13 , 72 5 –7 31.

[10] D. B. Williams, M. E. Stoll, B. L. Scott, D. A. Costa, W. J. Old-

ham, Jr., Chem. Commun. 2005, 1438–1440.

ACHTUNGTRENNUNG

¹⁹F NMR (282.4 MHz, [D₂]CH₂Cl₂): d=ꢀ74.9 ppm (CF₃); elemental anal-

ysis calcd (%) for C₉H₈Ag₂F₁₂N₂O₈S₄(844.16 gmol^ꢀ1): C 12.81, H 0.96, N

3.32, S 15.19; found: C 8.29, H 0.51, N 3.79, S 16.24. Single crystals of 11

were obtained from CH₂Cl₂at ꢀ208C.

[11] R. Arvai, F. Toulgoat, B. R. Langlois, J.-Y. Sanchez, M. Mꢅdebielle,

Tetrahedron 2009 , 65 , 536 1 –5 368.

[CuACHTUNGTRENNUNG(C₂H₄)ACHTUNGTRENNUNG(NTf₂)]₁(12): Ethylene was passed through a solution of 1

(232 mg, 0.25 mmol) in CH₂Cl₂(1 mL) at room temperature for 1 min.

Complex 12 precipitated at ꢀ208C in the form of colorless single crystals

suitable for an X-ray structure analysis. The supernatant solution was re-

moved through a syringe and the colorless crystalline solid was dried in a

stream of ethylene yielding 12. ¹H NMR (250.1 MHz, [D₂]CH₂Cl₂): d=

5.06 ppm (brs, 4H; CH); ¹³C NMR (62.9 MHz, [D₂]CH₂Cl₂): d=98.2

[12] S. Antoniotti, V. Dalla, E. DuÇach, Angew. Chem. 2010 , 122 , 803 2 –

8060; Angew. Chem. Int. Ed. 2010 , 49 , 786 0 –7 888 and references

cited therein.

[13] L. M. Galꢆn Sꢆnchez, G. W. Meindersma, A. B. Haan, Ind. Eng.

Chem. Res. 2009, 48, 10650–10656.

[14] J.-F. Huang, H. Luo, C. Liang, D.-e. Jiang, S. Dai, Ind. Eng. Chem.

Res. 2008 , 47 , 88 1 –8 88.

ACTHNUTRGNEUNG

(CH), 119.6 ppm (q, ¹J(C,F)=322 Hz; CF₃); ¹⁹F NMR (282.4 MHz,

[D₂]CH₂Cl₂): d=ꢀ74.9 ppm (CF₃); IR (neat): n˜ =3097 (vw), 2988 (vw),

[15] D. J. Tempel, P. B. Henderson, J. R. Brzozowski, R. M. Pearlstein,

T. R. Gaffney, US 2005/0276733A1, 2005.

1785 (vw), 1738 (vw), 1544 (vw), 1421 (w), 1390 (m), 1357 (m), 1340 (m),

Chem. Eur. J. 2013, 19, 1042 – 1057

ꢂ 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

www.chemeurj.org

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tribution graph for d

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1056

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Chem. Eur. J. 2013, 19, 1042 – 1057

Copper(I) and Silver(I) Bis(trifluoromethanesulfonyl)imide

FULL PAPER

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(C₂H₄)]X (X=any sub-

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non-metal, coordination number=3) resulted in five hits, in which

ꢀ

d

G

Received: May 17, 2012

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Akiyama, S. Kitagawa, Inorg. Chem. 1994 , 33 , 128 4 –1 291; b) M.

Revised: October 17, 2012

Published online: November 23, 2012

Chem. Eur. J. 2013, 19, 1042 – 1057

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1057

Article Doi

Copper(I) and silver(I) bis(trifluoromethanesulfonyl)imide and their interaction with an arene, diverse olefins, and an NTf2 --based ionic liquid

DOI: 10.1002/chem.201201740

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