Mono- And Dinuclear Coinage Metal Complexes Supported by an Imino-Pyridine-NHC Ligand: Structural and Photophysical Studies

DOI: 10.1021/acs.organomet.9b00449

Source and publish data:

Organometallics p. 3649 - 3661 (2019)

Update date:2022-08-17

Topics:

Authors:

Simler, Thomas

M?bius, Karen

Müller, Kerstin

Feuerstein, Thomas J.

Gamer, Michael T.

Lebedkin, Sergei

Kappes, Manfred M.

Roesky, Peter W.

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Article abstract of DOI:10.1021/acs.organomet.9b00449

A new imino-pyridine-NHC (NHC = N-heterocyclic carbene) hybrid ligand was accessed through a multistep synthesis, and its coordination chemistry was examined among coinage metals. Mononuclear copper, silver, and gold complexes as well as dinuclear homo- and heterometallic complexes were isolated and fully characterized by spectroscopic methods as well as X-ray crystallography. A comparative study of the structural and photophysical properties of the complexes was performed to get more insight into structure-property relationships. The photoluminescence (PL) properties were investigated in the solid state at temperatures between 20 and 295 K, and systematically compared with those of related complexes bearing a bipyridine-NHC ligand and previously reported by our group. The PL properties can be finely "tuned" depending on the coordinated metals, and the weak emission of the complexes can be traced back to the structural flexibility of the imino-pyridine-NHC framework.

Full text of DOI:10.1021/acs.organomet.9b00449

Article

pubs.acs.org/Organometallics

Cite This: Organometallics XXXX, XXX, XXX −XXX

Mono- and Dinuclear Coinage Metal Complexes Supported by an

Imino-Pyridine-NHC Ligand: Structural and Photophysical Studies

†

ller, Thomas J. Feuerstein, Michael T. Gamer,^†

†

Thomas Simler,* Karen Mo

bius, Kerstin Mu

‡

‡,§

,†

Sergei Lebedkin, Manfred M. Kappes,

and Peter W. Roesky*

†

Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), Engesserstr. 15, 76131 Karlsruhe, Germany

Institute of Nanotechnology, Karlsruhe Institute of Technology (KIT), Herrmann-von-Helmholtz-Platz 1, 76344

‡

Eggenstein-Leopoldshafen, Germany

Institute of Physical Chemistry, Karlsruhe Institute of Technology (KIT), Fritz-Haber-Weg 2, 76131 Karlsruhe, Germany

S Supporting Information

ABSTRACT: A new imino-pyridine-NHC (NHC = N-

heterocyclic carbene) hybrid ligand was accessed through a

multistep synthesis, and its coordination chemistry was

examined among coinage metals. Mononuclear copper, silver,

and gold complexes as well as dinuclear homo- and

heterometallic complexes were isolated and fully characterized

by spectroscopic methods as well as X-ray crystallography. A

comparative study of the structural and photophysical

properties of the complexes was performed to get more insight into structure−property relationships. The photoluminescence

(

PL) properties were investigated in the solid state at temperatures between 20 and 295 K, and systematically compared with

those of related complexes bearing a bipyridine-NHC ligand and previously reported by our group. The PL properties can be

ﬁnely “tuned” depending on the coordinated metals, and the weak emission of the complexes can be traced back to the

structural ﬂexibility of the imino-pyridine-NHC framework.

INTRODUCTION

“soft” ligands, and we reasoned that the substitution of “soft”

phosphine or alkyne groups by “harder” N-donor function-

alities may be beneﬁcial for the synthesis of heterometallic

complexes. We therefore examined the coordination behavior

■

Multinuclear, homo- or heterometallic, transition-metal com-

plexes have attracted great attention, partly because of the

interesting catalytic properties that may arise from an

appropriate combination of metal centers. In the case of

of bipyridyl-functionalized NHC ligands among d metal

cations. In the case of the bipyridine-NHC ligand L′ depicted

coinage metals, and more generally closed-shell d metal

in Chart 1, homo- and heterometallic complexes were isolated,

centers, speciﬁc metal−metal interactions have been observed

in polynuclear complexes and referred to as metallophilic d −

Chart 1. Structure of the Bipyridine-NHC Ligand L′ Used in

interactions. The resulting short metal−metal distances

the Previous Studies, Compared to That of the Imino-

are often associated with interesting photophysical properties

Pyridine-NHC Ligand L

3b,4

such as enhanced luminescence,

which has prompted the

synthesis of a large variety of polynuclear coinage metal

complexes. The design of the ligand plays a crucial role in

promoting or enforcing speciﬁc metal arrangements and

metallophilic interactions. Variations on the ligand may lead

to slightly diﬀerent structural arrangements, which have a

direct inﬂuence on the energies of the electronic transitions in

the corresponding complexes.

with diﬀerent photophysical properties depending on the

nature of the metal centers. Interestingly, among the dinuclear

complexes obtained, only the homometallic silver complexes

exhibited weak metallophilic interactions with shortened

intermetallic distances.

Following our previous studies of structure−property

relationships, we decided to examine options provided by a

In order to better understand the inﬂuence of metal−metal

interactions on the photophysical properties of the complexes,

our groups and others have been interested in the synthesis of

coinage metal complexes supported by functionalized poly-

dentate N-heterocyclic carbene (NHC) ligands. In this

context, phosphine-functionalized NHC ligands, as well as

alkynyl-functionalized NHC ligands, have been used to access

multinuclear d metal complexes. Following the “hard and soft

Received: July 3, 2019

acids and bases” (HSAB) concept, NHCs can be classiﬁed as

XXXX American Chemical Society

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Scheme 1. Synthetic Route Leading to the Imidazolium Salt L·HBr (8)

nitrogen side donor. In this context, we herein report the

synthesis of the new imino-pyridine-NHC ligand L (Chart 1)

which features a Schiﬀ base side arm donor. This new

framework results in a more ﬂexible ligand with diﬀerent steric

and electronic properties as compared with the ligand L′. Very

recently, the diﬀerent coordination behavior of the related 2,6-

pyridinediimine and 2,2’:6′,2″-terpyridine ligands was inves-

tigated and the electronic structures of the corresponding

Dean−Stark apparatus proved unsuccessful, probably because

of the insolubility of 7 in aromatic hydrocarbons.

The solid-state structure of 8 was established by single-

crystal X-ray crystallography (Figure 1) and revealed a close-

zirconium, cobalt and ruthenium complexes were determined.

The coordination chemistry of the new ligand L was examined

among coinage metals, leading to the formation of mono- and

dinuclear (homo- and heterometallic) complexes. The photo-

physical properties of the complexes were systematically

explored and compared to those of the corresponding

complexes supported by the bipyridine-NHC ligand L′.

RESULTS AND DISCUSSION

■

(

Ligand Synthesis. The imidazolium salt proligand L·HBr

8) was prepared according to the synthetic route depicted in

Figure 1. Molecular structure of 8 in the solid state. H atoms, except

for the imidazolium moiety, and noncoordinating solvent molecules

are omitted for clarity. Selected bond distances (Å) and angles [°]:

N1−C1 1.334(4), N2−C1 1.326(4), N4−C10 1.266(4); N2−C1−

N1 108.4(2).

Scheme 1. Although it involves several steps, the synthesis can

be readily performed on a multigram scale and does not

require chromatographic puriﬁcation for any intermediate

compounds. All the ligand precursors were obtained pure and

in high yield after simple recrystallization procedures.

After protection of the ketone group of 2-acetyl-6-

bromopyridine (1) as a dioxolane, 2 was converted in the

contact interaction between the NCHN proton and the

alcohol 3 by lithiation with nBuLi in ether at −78 °C,

bromide anion, suggesting H-bonding interaction in the solid

5e,11

treatment with DMF, and in situ reduction with NaBH .

state.

In the IR spectrum of 8, the absorption of the

−

Bromination of the alcohol was readily achieved by reaction

dangling imine group was detected at 1641 cm .

with PBr in dichloromethane, leading to the bromomethyl

Mononuclear Complexes. Formation of the air-stable

intermediate 4. Addition of N-DiPP-imidazole (5) resulted in

the formation of the imidazolium salt 6, which was obtained

almost quantitatively and in a pure form after trituration with

silver complex 9 was readily achieved using the silver oxide

procedure, more precisely, by reaction of the imidazolium

proligand 8 with Ag O in acetonitrile (Scheme 2). Completion

Et O. In order to avoid a halide scrambling in the imidazolium

of the reaction was evidenced by analysis of the H NMR

salt 7, the dioxolane protecting group in 6 was removed by

treatment with a mixture of aqueous HBr and acetone. The

imine group was ﬁnally introduced by heating 7 with excess

spectrum of the product where the signal for the acidic azolium

proton at δ 10.51 ppm had disappeared. In the C{ H} NMR

spectrum, the carbene resonance could be detected as a broad

,4,6-trimethylaniline in glacial acetic acid, yielding the

doublet at room temperature (δ 184.1 ppm, J ≈ 250 Hz)

CAg

imidazolium salt proligand 8. During this step, condensation

of the aniline with acetic acid was found to occur as a side

reaction, leading to the formation of N-mesityl acetamide. The

latter could be successfully removed by washing the crude

product with hot toluene. Attempted formation of the imine by

a standard condensation reaction in hot benzene or toluene

and removal of the water byproduct using molecular sieves or a

after long acquisition times. Coalescence into a broad singlet

was observed at higher temperature (323 K) (Figures S23 −

S25 ). The solid-state structure of 9 (Figure 2) established a

monomeric [AgBr(L)] complex with a noncoordinating imino-

pyridine moiety, in contrast to the polymeric arrangement

obtained using the bipyridine-substituted ligand L′ (Chart

1). This diﬀerent association in the solid state may be the

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Scheme 2. Synthesis of the Silver Complex 9 and

Transmetalation to the Gold Complexes 10 and 11

signals at δ 184.0 and 190.8 ppm, respectively, in the typical

5d,8b,14

range for related NHC gold(I) complexes.

It is worth

noting that both signals are deshielded compared to the

resonances of NHC gold chloride complexes (typically in the

range 165−175 ppm). This downﬁeld shift has been assigned

to an increased donor ability of the anionic coligand on the

14a,16

gold metal center (Cl < I < C F ).

The crystal structures of 10 (Figure 3) and 11 (Figure 4)

conﬁrmed the formation of mononuclear complexes of the

Figure 3. Molecular structure of 10 in the solid state. H atoms are

omitted for clarity. Selected bond distances (Å) and angles [°]: Au−I

.5437(7), Au−C1 1.999(9), N1−C1 1.349(10), N2−C1 1.333(10),

C10−N4 1.295(14); C1−Au−I 177.7(2), N2−C1−N1 105.3(7).

Figure 2. Molecular structure of 9 in the solid state. H atoms are

omitted for clarity. Selected bond distances (Å) and angles [°]: Ag−

Br 2.4332(4), Ag−C1 2.078(3), N1−C1 1.350(4), N2−C1 1.351(4),

N4−C10 1.277(5); C1−Ag−Br 177.24(9), N1−C1−N2 104.4(3).

result of the increased steric demand of the imino-pyridine-

Figure 4. Molecular structure of 11 in the solid state. H atoms are

omitted for clarity. Only one disordered position of the C group is

depicted for clarity. Selected bond distances (Å) and angles [°]: Au−

C1 2.011(3), Au−C33A 2.054(7), N1−C1 1.357(4), N2−C1

1.344(3), N4−C10 1.266(4); C1−Au−C33A 175.8(4), N2−C1−

N1 104.3(2).

NHC ligand L. Complex 9 features a quasi-linear C^N^H^C−Ag−

6 5

Br arrangement with a bonding angle of 177.24(9)° and a

NHC

−Ag separation of 2.078(3) Å, in the typical range for

NHC silver complexes.

The silver complex 9 was used as a starting precursor to

access other coinage metal complexes by transmetalation

(Scheme 2). Reaction with [AuCl(tht)] in acetonitrile led

type [Au(X)(L)] (X = I, C F ) with a quasi-linear geometry

NHC

to the immediate formation of a white insoluble precipitate of

around the gold center and C −Au−X bond angles ranging

NHC

silver halide. However, the H NMR spectrum of the product

from 175.8(4) to 177.7(2)°. The C −Au bond distance in

revealed the presence of two species featuring similar chemical

shifts, probably the result of a partial halide scrambling (Br/Cl)

occurring during the transmetalation process. Similar observa-

tions have already been reported using a phosphine-function-

the iodido complex 10 (1.999(9) Å) is in a similar range as

4a,17

that for related [AuI(NHC)] complexes,

and slightly

NHC

shorter than the C −Au separation in the C F analogue 11

(2.011(3) Å), consistent with the higher trans inﬂuence of the

pentaﬂuorophenyl substituent (as also observed from the

carbene C{ H} NMR chemical shift). Indeed, an approx-

imate correlation was found between the C −Au bond

distance and the NMR chemical shift of the carbene

alized NHC ligand. In order to circumvent this problem, a

subsequent halide exchange was carried out by treatment of

the crude product with potassium iodide in acetone, resulting

in the clean formation of the gold iodide complex 10. The

pentaﬂuorophenyl analogue 11 was prepared by treatment of 9

with [Au(C F )(tht)] and the product isolated in 53% yield

NHC

14a

resonance.

Complexes of the type [M(L) ](BF ) (M = Ag, Au)

after crystallization from Et O. In the C{ H} NMR spectra,

featuring two ligands and one central coinage metal cation

were targeted as they may serve as building blocks for the

the carbene resonances of 10 and 11 were detected as sharp

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synthesis of dinuclear complexes. The silver complex 12 was

heteroleptic [AgBr(L)] complex 9 (2.078(3) Å). A similar

obtained by reaction of 9 with AgBF in acetonitrile (Scheme

trend has already been observed in related phosphine-NHC

). Under the same conditions and in the presence of

silver complexes. For all the mononuclear complexes 9−13,

the imine CN resonances were detected in the IR spectra in

−

Scheme 3. Synthesis of [Ag(L) ](BF ) (12) and

the range 1639−1649 cm , consistent with the presence of

dangling imine groups.

[

Au(L) ](BF ) (13)

2 4

Synthesis of the corresponding mononuclear copper(I)

complex [Cu(L) ](BF ) by reaction of 9 with [Cu(MeCN) ]-

(

BF ) did not proceed cleanly and resulted in a mixture of

products containing the dinuclear [AgCu(L) ](BF ) complex,

4 2

which was identiﬁed by mass spectrometry. The diﬀerent

reactivity observed in the case of copper(I) compared with that

of the heavier coinage metals may be due to the high aﬃnity of

the former for the imino-pyridine moiety. Coordination of the

copper cation to the chelating nitrogen donors may compete

with the NHC transfer reaction, leading to an incomplete

[

AuCl(tht)], the corresponding gold complex 13 was isolated.

transmetalation and formation of [AgCu(L) ](BF ) as a side

The identity of both complexes was conﬁrmed by ESI-MS

spectrometry with the most abundant signals arising from the

4 2

product. To further probe the coordination behavior of the

imino-pyridine moiety toward Cu , the imidazolium salt 8 was

[M(L) ] (M = Ag, Au) cations.

treated with [CuBr(SMe )] and AgBF in the ratio 2:1:3,

In the H NMR spectra of both complexes, the methylene

respectively, resulting in the formation of the tris-cationic

complex 14 (Scheme 4). The solid-state structure (Figure 6),

spacer gave rise to a singlet in the range 5.39−5.40 ppm,

suggesting unrestricted rotation of the uncoordinated imino-

pyridine moiety. In the ¹³C{ H} NMR spectrum of 12, the

carbene resonance was detected as two doublets centered at δ

Scheme 4. Synthesis of the Tris-Cationic Complex

[(LH) Cu](BF ) (14)

107

109

82.3 ppm ( J( C− Ag) = 183 Hz and J( C− Ag) = 211

4 3

Hz), conﬁrming coordination of the NHC donor to the Ag

center. This splitting pattern is the result of a coupling with the

two isotopes of silver (¹⁰⁷Ag 51.8% and Ag 48.2%, both I =

109

/2) that are present at natural abundance. In contrast, only

one singlet at δ 185.4 ppm was detected for the corresponding

resonance in the gold complex 13. These NMR spectroscopic

data are very similar to those of the corresponding complexes

supported by the ligand L′ (Chart 1), underlying the

structural similarity between both ligands. The structures of 12

and 13 (Figures 5 and S6) were further conﬁrmed by X-ray

diﬀraction studies and revealed isostructural complexes with

NHC

linear arrangements around the metal centers (C −M−

NHC

(M = Ag, Au) bond angles of ca. 179.4°). The C −Ag

bond distance in 12 (2.066(2) Å) is slightly shorter (within

experimental error) than the corresponding separation in the

Figure 6. Molecular structure of the cation of 14 in the solid state. H

atoms, except for the imidazolium moiety, are omitted for clarity.

Only the imino-pyridine moiety of the upper ligand and one

disordered position of the iPr groups are depicted for clarity. Selected

bond distances (Å) and angles [°]: Cu−N3 2.045(5), Cu−N4

2.012(5), Cu−N7 2.068(5), Cu−N8 2.010(5), N1−C1 1.320(8),

N2−C1 1.327(7), N4−C10 1.278(8), N8−C42 1.309(7); N4−Cu−

N3 80.5(2), N8−Cu−N7 81.1(2), N3−Cu−N7 112.9(2), N4−Cu−

N7 133.5(2), N8−Cu−N3 134.5(2), N8−Cu−N4 122.2(2), N1−

C1−N2 108.0(5).

as established by single-crystal X-ray diﬀraction studies,

revealed a distorted tetrahedral coordination geometry around

the Cu center, the latter chelated by two imino-pyridine

Figure 5. Molecular structure of the cation of 12 in the solid state. H

atoms and noncoordinating solvent molecules are omitted, and only

one disordered position of the mesityl and iPr groups is depicted for

clarity. Selected bond distances (Å) and angles [°]: Ag−C1 2.066(2);

N1−C1 1.357(3), N2−C1 1.344(3), N4A-C10 1.36(2); C1−Ag−C1′

moieties. In the IR spectrum, the coordinated imines gave rise

−1

to an absorption band centered at 1594 cm , red-shifted in

comparison to the resonance for the dangling imine in 8−13.

179.38(12), N2−C1−N1 104.0(2).

In the H NMR spectrum, the NCHN imidazolium protons

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were detected as one downﬁeld triplet at δ 8.83 ppm (⁴J_H_H

state. This intermetallic distance is signiﬁcantly larger than

that observed when using the bipyridine-NHC ligand L′

12b

.6 Hz).

Dinuclear Complexes. Homometallic. As the imino-

(3.103(1) Å), further highlighting the inﬂuence of the ligand

framework on the structural arrangement of the complexes.

Although only one isomer was isolated in the solid state,

ﬂuxional behavior was observed in solution, possibly due to a

“head-to-head”/“head-to-tail” isomerization (Scheme 6). Ac-

pyridine moiety in the mononuclear complexes 12 and 13 is

noncoordinating, addition of a second coinage metal was

considered, in order to prepare homo- or heterometallic

dinuclear complexes.

The dinuclear silver complex 15 was obtained in good yield

by reaction of 12 with AgBF₄(Scheme 5) and fully

Scheme 6. Possible “Head-to-Head”/“Head-to-Tail”

Isomerization of the Homometallic Dinuclear Complexes

15 and 16 in Solution

Scheme 5. Synthesis of the Dinuclear Silver Complexes 15

characterized. The UV−vis spectrum of the complex (Figures

S58 −S59 ) features an absorption band centered at 393 nm,

consistent with the yellow appearance of the product. In the IR

spectrum, the coordinated imine gave rise to a resonance at

cordingly, the H NMR spectrum of 15 in CDCl featured

broad signals at room temperature. Sharper resonances were

observed in CD CN, in which case the methylene spacer gave

−

593 cm , red-shifted compared to that of the mononuclear

complex 12 (1648 cm ). The solid-state structure of 15

Figure 7) was established by X-ray crystallography, revealing a

rise to a singlet at δ 5.73 ppm. Coordination of the NHC to

the silver center was conﬁrmed by the presence of two

−

107

(

doublets at δ 183.7 ppm ( J( C− Ag) = 244 Hz and

1 13 109 13 1

J( C− Ag) = 282 Hz) in the C{ H} NMR spectrum.

The dinuclear [Cu (L) ](BF ) complex 16 was obtained

4 2

using another synthetic route, by reaction of the imidazolium

salt proligand 8 with mesitylcopper [MesCu], followed by

halide abstraction using AgBF (Scheme 7). It was isolated in

Scheme 7. Synthesis of the Dinuclear Copper Complex 16

Figure 7. Molecular structure of the cation of 15 in the solid state. H

atoms and noncoordinating solvent molecules are omitted for clarity.

Selected bond distances (Å) and angles [°]: Ag1−N7 2.385(4), Ag1−

N8 2.260(4), Ag1−C1 2.090(5), Ag2−N3 2.383(4), Ag2−N4

.251(4), Ag2−C33 2.083(5), N1−C1 1.356(6), N2−C1 1.360(6),

good yield as a slightly air-sensitive orange-brown powder. The

color of the complex is in line with the presence of a weak

absorption band centered at 464 nm in the UV−vis absorption

spectrum. Owing to poor crystal quality and weak diﬀraction,

only a preliminary crystal structure (Figure S11 ) could be

obtained and the bond distances will therefore not be

discussed in detail. However, the connectivity of the atoms

could be unambiguously determined and revealed a bridged

dinuclear complex with a “head-to-head” arrangement, in

contrast to the “head-to-tail” arrangement observed in the

dinuclear silver complex 15. The intermetallic distance (Cu···

Cu separation of ca. 5.02 Å) is substantially longer than in the

N4−C10 1.288(6), N8−C42 1.284(6); N8−Ag1−N7 70.52(14),

C1−Ag1−N7 141.2(2), C1−Ag1−N8 148.2(2), N4−Ag2−N3

1.53(14), C33−Ag2−N3 135.1(2), C33−Ag2−N4 153.1(2), N1−

C1−N2 104.3(4), N6−C33−N5 104.5(4). The asymmetric unit of

5·MeCN contains two molecules with very similar metrical data.

“head-to-tail” arrangement with the two silver centers each

bridged by one NHC donor and one imino-pyridine moiety.

The asymmetric unit of 15·MeCN contains two molecules

with very similar metrical data and only one of them will be

discussed here. Both silver centers lie in distorted trigonal

planar coordination environments (sum of the angles around

Ag of 359.7−359.9°). The C −Ag bond distances are in the

range of 2.083(5)−2.090(5) Å and thus are slightly longer

compared to that in the mononuclear silver complex 12

bipyridine-NHC analogous complex (3.217(1) Å), ruling out

any metallophilic interaction.

NHC

The coordinated imino donor in 16 gave rise to a strong

−

absorption band at 1593 cm in the IR spectrum, at similar

(

2.066(2) Å). The large Ag···Ag separation of 4.311(1)−

wavenumbers compared to those in 14 and 15. In both CDCl

.359(1) Å precludes any metal−metal interaction in the solid

and CD CN solutions, the H and C{ H} NMR spectra

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indicated the presence of two isomers exhibiting similar

chemical shifts and tentatively assigned to the “head-to-head”

and “head-to-tail” arrangements (Scheme 6). It is worth noting

that, for both isomers, a diastereotopic splitting of the

methylene CH protons was observed in CDCl leading to

rotation of the mesityl substituents gave rise to two distinct

aromatic CH resonances, indicating a slow exchange on the

NMR time scale. Interestingly, in CD CN, only one singlet at δ

5.24 ppm was observed for the CH spacer in 17 (and two

broad resonances for 18), and one resonance integrating for

2H was detected for the mesityl aromatic protons. These

signals are consistent with a ﬂuxional process occurring at a

an AB pattern.

Attempted synthesis of the corresponding dinuclear gold

analogue did not lead to the expected [Au (L) ](BF )

higher rate in CD CN. In the C{ H} NMR spectra, the

complex. Instead, reaction of 13 with [AuCl(tht)] in the

presence of AgBF₄resulted in the formation of the

heterometallic silver−gold complex 17 (Scheme 8).

carbene resonances were detected at δ 187.2 (CD CN) for 17,

and 185.8 (CDCl ) for 18.

The solid-state structures of 17 and 18 (Figure 8) were

unambiguously established by X-ray crystallography. Both

complexes are isostructural and exhibit a “head-to-head”

arrangement with the gold atom coordinated by two NHCs

trans to each other and the second metal (Ag for 17 and Cu for

Scheme 8. Synthesis of the Heterometallic Dinuclear

Complexes 17 and 18

8) lying in a distorted tetrahedral coordination environment,

NHC

surrounded by two imino-pyridine moieties. The C −Au

bond distances are identical within experimental error

(

2.014(3)−2.031(5) Å). The “head-to-head” arrangement

observed in the case of 17 and 18 contrasts with the “head-

to-tail” association in the homometallic silver complex 15,

NHC

probably resulting from the formation of stronger C −Au

bonds in 17 and 18. Similar arrangements were also obtained

using the bipyridine-NHC ligand L′, and computational

NHC

reports showed that the strength of the C −M bond within

Heterometallic. As mentioned above, the reaction of 13

with AgBF₄led to the metalation of the imino-pyridine

moieties and formation of the dinuclear AgAu complex 17,

isolated as a yellow solid in moderate yield after crystallization

group 11 metals follows the order Au > Cu > Ag. Compared

with ligand L′, a larger Ag···Au separation is observed with the

imino-pyridine-NHC ligand L (5.135 Å in 17 vs 4.321 Å),

while a slightly shorter Cu···Au separation is present (4.913 Å

in 18 vs 5.091 Å). In all cases, the intermetallic distances

largely exceed the sum of the corresponding van der Waals

radii, excluding any metallophilic interaction.

(Scheme 8). The UV−vis absorption spectrum of 17 is very

similar to that of the homometallic AgAg complex 15, with an

absorption band centered at 394 nm. The CuAu analogue 18

was prepared by treatment of 13 with freshly generated

Photoluminescence Properties. Figure 9 compares

temperature-dependent photoluminescence excitation (PLE)

and emission spectra of the solid (polycrystalline) mono-

nuclear complexes 10 (Au) and 12 (Ag) and homo- and

heterometallic dinuclear complexes 15−18 (AgAg, CuCu,

AgAu, and CuAu, respectively). All complexes show rather

similar PLE spectra with the onset of absorption at 400−420

nm (slightly blue shifting upon cooling down to 20 K) and two

major bands at about 280 and 360 nm. Two characteristic

emission patterns are observed: a broad band at about 560 nm

(10, 18) and a vibronically structured blue emission peaked at

430−435 nm (15, 17). The photoluminescence emission (PL)

[

Cu(MeCN) ](BF ). It featured in the UV−vis spectrum an

absorption band centered at 466 nm with a shoulder at 560

nm, consistent with the red-brown color of the product. In the

IR spectra of 17 and 18, a bathochromic shift of the imine

−

CN absorption bands was observed (v

̃ = 1591−1592 cm

−

vs 1642 cm for 13), resulting from the coordination of the

imino-pyridine moiety in the AgAu and CuAu complexes,

respectively.

In the H NMR spectra of 17 and 18 in CDCl , restricted

rotation of the coordinated imino-pyridine moieties was

indicated by the diastereotopic splitting of the CH methylene

protons, leading to an AB spin system. In addition, hindered

Figure 8. Molecular structures of the cations of 17 and 18 in the solid state. H atoms and noncoordinating solvent molecules are omitted for clarity.

Selected bond distances (Å) and angles [°]: for 17: Au−C1 2.014(3), Ag−N3 2.360(3), Ag−N4 2.278(3), N1−C1 1.343(5), N2−C1 1.352(5),

N4−C10 1.287(5); C1−Au−C1′ 176.4(2), N3−Ag−N3′ 117.74(14), N4−Ag−N3′ 133.09(12), N4−Ag−N3 71.96(11), N4−Ag−N4’ 137.7(2),

N1−C1−N2 104.6(3); for 18: Au−C1 2.031(5), Cu−N3 2.053(4), Cu−N4 2.009(4), N1−C1 1.335(6), N2−C1 1.334(6), N4−C10 1.289(6);

C1−Au−C1′ 176.7(3), N3−Cu−N3′ 110.0(2), N4−Cu−N3′ 133.35(15), N4−Cu−N3 81.31(15), N4−Cu−N4′ 124.4(2), N2−C1−N1

106.1(4).

DOI: 10.1021/acs.organomet.9b00449

Organometallics XXXX, XXX, XXX−XXX

Organometallics

Article

complexes upon UV photoexcitation. On the other hand, the

PL properties of all imino-pyridine-NHC complexes are weak

(

see below). Accordingly, the observed emission only

represents a minor channel of electronic relaxation. This is

also the case at low temperatures since the PL intensity

increases only moderately by cooling the complexes down

(

Figure 9). The coinage metal complexes based on the

bipyridine-NHC ligand (Chart 1) and studied in our previous

work demonstrated a moderately weak PL at ambient

temperature with a PL quantum yield up to 0.4%. However,

the PL intensity typically strongly increased by decreasing the

temperature. In comparison, a much weaker emission,

particularly at low temperatures, was observed for the imino-

pyridine-NHC complexes in this work.

Their PL eﬃciency at ambient temperature was estimated to

be signiﬁcantly less than 0.1% (as limited by the

autoluminescence of a PTFE integrating sphere used for

these measurements; see the Experimental Section). In line

with the results for crystalline samples, practically no visible PL

was observed for the imino-pyridine-NHC complexes in DCM

solutions. Especially for the gold and silver complexes, such

low PL eﬃciency is also in contrast with numerous examples of

brightly luminescent NHC complexes of these metals. We

tentatively ascribe the weak emission, at least in part, to the

structural ﬂexibility of the imino-pyridine-NHC framework.

The latter might provide for the eﬃcient nonradiative

relaxation channels and PL quenching. In this context, it has

to be kept in mind that the structural ﬂexibility of a ligand,

which is generally favorable for the design of polynuclear

complexes and chemical functionalization, may compromise

the PL properties.

Figure 9. Photoluminescence excitation (PLE) and emission (PL)

spectra of polycrystalline complexes 10, 12, and 15−18 at

temperatures of 20, 150, and 295 K. The PL and PLE spectra were

excited at 350 nm and recorded at 560 (10), 430/460 (12, 20/295

K), 432 (15−17), and 580 nm (18), respectively. The asterisk on the

emission curves of 10 indicates the second-order-diﬀracted excitation

line (not completely removed by a long pass emission ﬁlter).

spectra of 12 and 16 demonstrate both the structured blue

emission and a broad band tailing over 600 nm. Based on the

microsecond-long PL decays, both components can be

assigned to phosphorescence. The longest PL lifetime of

CONCLUSIONS

■

The coordination chemistry of the new imino-pyridine-NHC

ligand L, obtained through a multistep high yield procedure,

was investigated toward coinage metals. Treatment of the

imidazolium salt proligand with silver oxide led to the silver

complex [AgBr(L)], which was successfully used as a precursor

to aﬀord mononuclear silver and gold complexes. Further

54/69 μ s at 20/295 K was recorded for the blue emission of

7 (Figure S60 ). The PL signatures of the imino-pyridine-

NHC complexes closely resemble the phosphorescence

observed for the solid bipyridine-NHC metal complexes,

including a typical vibronically structured emission at about

80 nm and a broad band around 580 nm observed for the

metalation with Cu and Ag cations aﬀorded homo- and

dinuclear AuAg complex (without metallophilic interaction).

heterometallic dinuclear complexes. In the [M (L) ](BF ) (M

4 2

Similar to the bipyridine-NHC complexes, we assign the

structured blue emission of the imino-pyridine-NHC com-

plexes to the intraligand (IL) transitions mainly centered on

imino-pyridine units. The red-shifted broad phosphorescence

bands, most pronounced in 10 and 18, may be tentatively

assigned to the metal to ligand charge transfer (MLCT) states,

in particular involving gold atoms. We also conclude that the

PL properties of the studied complexes can be ﬁnely “tuned”

by the coordinated metals: for instance, 17 (CuAu) and 18

= Ag, Cu) homometallic complexes, a “head-to-head”/“head-

to-tail” isomerization was observed in solution. In contrast, in

the case of the AgAu and CuAu heterometallic analogues, the

gold center is exclusively coordinated by two NHC donors

arranged in a trans fashion. Structural characterization of the

complexes revealed the absence of metal−metal interaction in

the solid state. The PL properties of the complexes were

systematically examined and can be ﬁnely “tuned” depending

on the nature of coordinated metals. The diﬀerent results show

that minor ligand modiﬁcations can inﬂuence the structural

ﬂexibility of the ligand, resulting in slightly altered solid-state

arrangements and PL properties. Besides, the modiﬁcation of a

bipyridine moiety into a structurally similar imino-pyridine

group may lead to further reactivity involving the coordinated

imine group, which is currently under investigation.

(

AgAu) are structural homologues, but they demonstrate

diﬀerent emission spectra.

The PLE onset at 400−420 nm (Figure 9) is consistent with

the yellowish color of 10, 12, 15, and 17, but in obvious

discrepancy with the orange-brown and red-brown colors of

the copper-containing complexes 16 and 18. A signiﬁcant

lowering of the HOMO−LUMO gap in the last compounds is

likely due to HOMO contribution of the d-orbitals of

EXPERIMENTAL SECTION

General Considerations. All air- and moisture-sensitive manip-

ulations were performed under dry N or Ar atmosphere using

■

copper. However, the corresponding low-energy excited

states seemingly neither contribute to the PL nor eﬀectively

quench the higher-energy emission (in 16). Considering the

molecular structures of 16 and 18, this unusual observation

might indicate some structural reorganization of these

standard Schlenk techniques or in an argon-ﬁlled MBraun glovebox,

unless otherwise stated. Prior to use, CH Cl and acetonitrile were

dried by reﬂuxing over P O and CaH , respectively, and distilled

DOI: 10.1021/acs.organomet.9b00449

Organometallics XXXX, XXX, XXX−XXX

Organometallics

Article

under a nitrogen atmosphere. N,N-Dimethylformamide (DMF) and

N,N-dimethylacetamide (DMA) were dried by reﬂuxing over CaH₂

comments for each data set are given in the Supporting Information .

Summary of the crystal data, data collection and reﬁnement for the

diﬀerent compounds are given in Tables S1 and S2 .

and distilled under reduced pressure. Other solvents (THF, Et O,

toluene, and n-pentane) were dried using an MBraun solvent

puriﬁcation system (SPS-800). THF was additionally distilled under

nitrogen from potassium benzophenone ketyl before storage over 4 Å

molecular sieves. CDCl and CD CN were dried over 4 Å molecular

Synthesis of 2-(Bromomethyl)-6-(2-methyl-1,3-dioxolan-2-

yl) Pyridine (4). To a solution of 3 (2.50 g, 12.8 mmol) in CH

(1.2 mL, 3.47 g,

(50 mL) precooled at 0 °C was added dropwise PBr

12.8 mmol) under argon atmosphere. The resulting solution was

stirred at 0 °C for 1 h and allowed to reach room temperature. After 2

h, the reaction mixture was quenched by slow addition of saturated

aqueous K CO solution until the aqueous phase was basic. The

sieves and were degassed by freeze−pump−thaw cycles. N-DiPP-

22,23

imidazole (5), [AuCl(tht)], [Au(C F )(tht)],

and mesityl-

copper [CuMes] were prepared according to the literature

procedures. The synthesis of 1,

0a,25 10

2 , and 3 has already been

organic layer was separated, and the aqueous phase was extracted with

reported but is detailed in the Supporting Information for more

clarity. All other chemicals were obtained from commercial sources

and used without further puriﬁcation.

CH Cl (3 × 50 mL). The combined organic extracts were washed

with brine and dried over MgSO . Evaporation of the solvent under

reduced pressure aﬀorded the pure desired compound as a white

NMR spectra were recorded on Bruker spectrometers (Avance III

solid. Yield: 3.06 g (11.9 mmol), 93%. Anal. Calcd for C H BrNO

00 MHz, Avance 400 MHz, or Avance III 400 MHz). Chemical

(258.12): C, 46.53; H, 4.69; N, 5.43. Found: C, 46.54; H, 4.35; N,

shifts are referenced using signals of the residual protio solvent ( H)

5.56. H NMR (400.30 MHz, CDCl ): δ [ppm]: 7.70 (t, J = 7.8

3 HH

or the solvent ( C{ H}) and are reported relative to tetramethylsi-

Hz, 1H, p-CH_p_y_r), 7.47 (dd, J = 7.8 Hz, J = 1.0 Hz, 1H, m-

HH HH

CH_p_y_r), 7.41 (dd, J = 7.7 Hz, J = 1.0 Hz, 1H, m-CH _p_y_r), 4.60

lane, or externally relative to CFCl ( F). All NMR spectra were

HH HH

measured at 298 K, unless otherwise speciﬁed. The multiplicity of the

signals is indicated as s = singlet, d = doublet, t = triplet, sept = septet,

m = multiplet, and br = broad. Assignments were determined on the

(s, 2H, CH Br), 4.15−3.83 (m, 4H, OCH ), 1.73 (s, 3H, CH ).

13 1

C{ H} NMR (100.66 MHz, CDCl ): δ [ppm]: 160.9 (C ), 156.9

pyr

(

C_p_y_r), 137.7 (CH_p_y_r), 122.9 (CH ), 118.7 (CH ), 108.6 (CCH ),

pyr pyr 3

basis of unambiguous chemical shifts, coupling patterns, and C-

5.1 (OCH ), 34.2 (CH Br), 25.4 (CH ).

Synthesis of 6. Compound 4 (3.04 g, 11.8 mmol) and N-DiPP-

DEPT experiments or 2D correlations ( H− H COSY, H− C

HMQC, H− C HMBC).

imidazole (5) (3.23 g, 14.1 mmol) were dissolved in acetonitrile (50

mL), and the resulting mixture was stirred overnight at room

temperature. The solvent was removed in vacuo and the resulting

−

Infrared (IR) spectra were recorded in the region 4000−400 cm

on a Bruker Tensor 37 FTIR spectrometer equipped with a room

temperature DLaTGS detector and a diamond attenuated total

reﬂection (ATR) unit. UV−vis spectra were recorded in dry and

degassed CH Cl on a Varian Cary 50 spectrophotometer. EI-Mass

solid was triturated with Et O. Filtration and drying of the solid under

vacuum aﬀorded 6 as a white powder. Yield: 5.63 g (11.6 mmol),

98%. Anal. Calcd for C H BrN O (486.45): C, 61.73; H, 6.63; N,

spectra were recorded at 70 eV on a Thermo Scientiﬁc DFS. ESI mass

spectra were recorded on an LTQ Orbitrap XL Q Exactive mass

spectrometer (Thermo Fisher Scientiﬁc, San Jose, CA) equipped with

a HESI II probe. Elemental analyses were carried out with an

elementar Vario Micro Cube.

.64. Found: C, 61.74; H, 6.31; N, 8.96. H NMR (400.30 MHz,

CDCl ): δ [ppm]: 10.37 (t, J = 1.5 Hz, 1H, CH ), 8.16 (t, J

imid

≈

J_H_H≈ 1.7 Hz, 1H, CH ), 7.97 (dd, J = 7.7 Hz, J = 0.9 Hz,

3 3

imid

H, CH ), 7.79 (t, J = 7.7 Hz, 1H, CH ), 7.57 (dd, J = 7.9

pyr HH pyr HH

Hz, J = 0.9 Hz, 1H, CH ), 7.54 (t, J = 8.0 Hz, 1H, p-CH_D_i_P_P),

pyr

Photoluminescence (PL) measurements were performed with a

Horiba Jobin Yvon Fluorolog-322 spectrometer. A Hamamatsu

R9110 photomultiplier was used as detector for the emission spectral

range of about 300−850 nm. The solid samples (crystalline powders)

were measured as dispersions in a thin layer of viscous polyﬂuoroester

oil (Aldrich) placed between two 1 mm thin quartz (Spectrosil 2000)

plates. All emission spectra were corrected for the wavelength-

dependent response of the spectrometer and detector (in relative

photon ﬂux units). The emission decay traces were recorded by

connecting the photomultiplier to a 500 MHz LeCroy LT322

oscilloscope (via a 50, 500, or 2500 Ω load depending on the decay

time scale) and using a nitrogen laser (∼2 ns, ∼5 μJ per pulse) for

pulsed excitation at 337 nm. Several hundred traces were typically

acquired and averaged. PL eﬃciencies of solid complexes at ambient

temperature were determined at the excitation wavelength of 350 nm

using an integrating sphere out of optical PTFE, which was installed

into the sample chamber of the spectrometer, according to the

.31 (d, J = 8.0 Hz, 2H, m-CH_D_i_P_P), 7.11 (t, J ≈ J ≈ 1.8 Hz,

H, CH ), 6.29 (s, 2H, CH N), 4.13−3.83 (m, 4H, OCH ), 2.28

imid

(

sept, J = 6.8 Hz, 2H, CH(CH ) ), 1.66 (s, 3H, CH ), 1.22 (d,

HH 3 2 3

J_H_H= 6.8 Hz, 6H, CH(CH ) ), 1.13 (d, J_H_H= 6.8 Hz, 6H,

CH(CH ) ). C{ H} NMR (75.47 MHz, CDCl ): δ [ppm]: 161.1

(

C_a_r_o_m), 152.5 (C_a_r_o_m), 145.5 (C_a_r_o_m), 138.5 (CH_a_r_o_m), 138.3 (CH_a_r_o_m),

32.1 (CH_a_r_o_m), 130.3 (C_a_r_o_m), 124.8 (CH_a_r_o_m), 124.1 (CH_a_r_o_m), 123.8

(

CH_a_r_o_m), 123.5 (CH_a_r_o_m), 119.7 (CH_a_r_o_m), 108.5 (CCH ), 65.2

OCH ), 54.0 (CH N), 28.8 (CH(CH ) ), 25.1 (CH ), 24.5

CH(CH ) ), 24.4 (CH(CH ) ).

3 2

Synthesis of 7. Compound 6 (5.63 g, 11.6 mmol) was dissolved

in a mixture of acetone (40 mL) and 10% aqueous HBr solution (30

mL), and the resulting clear yellow solution was stirred overnight at

room temperature. The reaction mixture was neutralized by addition

of NaHCO , concentrated in vacuo and extracted with CH Cl (3 ×

0 mL). The combined organic extracts were washed with a saturated

NaBr aqueous solution and dried over MgSO . Evaporation of the

method of de Mello et al. The lowest attainable PL eﬃciency

solvent under reduced pressure aﬀorded 7 in a pure form as a white

(

∼0.01−0.1% depending on the PL spectral range) was mainly

solid. Yield: 5.09 g (11.5 mmol), 99%. Anal. Calcd for C H BrN O

limited by the autoluminescence of the integrating sphere.

(

442.40): C, 62.44; H, 6.38; N, 9.50. Found: C, 62.42; H, 6.35; N,

Suitable crystals for the X-ray analysis of all compounds were

obtained as described below. A suitable crystal was covered in mineral

oil (Aldrich) and mounted on a glass ﬁber. The crystal was transferred

directly to the cold stream of a STOE IPDS 2 (150, 200, or 210 K) or

a STOE StadiVari (100 or 150 K) diﬀractometer. All structures were

.46. H NMR (400.30 MHz, CDCl ): δ [ppm]: 10.51 (t, J = 1.5

3 HH

Hz, 1H, CH ), 8.21 (dd, J = 7.6 Hz, J = 1.1 Hz, 1H, CH ),

imid

pyr

.08 (t, J ≈ J ≈ 1.7 Hz, 1H, CH ), 8.01 (dd, J = 7.8 Hz,

imid

^JHH = 1.0 Hz, 1H, CH ), 7.92 (t, J = 7.7 Hz, 1H, CH ), 7.53 (t,

^JHH = 7.8 Hz, 1H, p-CH ), 7.30 (d, J ⁼⁷^.⁸^H^z^,²^H^,^m^-^C^HDiPP),

pyr

solved by using the program SHELXS/T and Olex2. The

remaining non-hydrogen atoms were located from successive

diﬀerence Fourier map calculations. The reﬁnements were carried

DiPP

7.19 (t, JHH ≈ JHH ≈ 1.8 Hz, 1H, CHimid), 6.41 (s, 2H, CH

(s, 3H, C(O)CH ), 2.27 (sept, JHH = 6.8 Hz, 2H, CH(CH )

(d, JHH = 6.8 Hz, 6H, CH(CH

CH(CH

N), 2.60

), 1.19

HH = 6.8 Hz, 6H,

): δ [ppm]: 198.9

), 153.4 (Carom), 152.6 (Carom), 145.4 (Carom), 138.8

out by using full-matrix least-squares techniques on F by using the

)

), 1.12 (d,

). C{ H} NMR (75.47 MHz, CDCl

program SHELXL. The H atoms were introduced into the

geometrically calculated positions (SHELXL procedures) unless

otherwise stated and reﬁned riding on the corresponding parent

atoms. In each case, the locations of the largest peaks in the ﬁnal

diﬀerence Fourier map calculations, as well as the magnitude of the

residual electron densities, were of no chemical signiﬁcance. Speciﬁc

)

(C(O)CH

(CHarom), 138.5 (CHarom), 132.1 (CHarom), 130.2 (Carom), 127.8

(CH_a_r_o_m), 124.9 (CH_a_r_o_m), 124.1 (CH_a_r_o_m), 123.8 (CH_a_r_o_m), 121.8

(CH_a_r_o_m), 53.7 (CH N), 28.8 (CH(CH ) ), 25.6 (CH ), 24.39

(CH(CH ) ), 24.37 (CH(CH ) ).

3 2

DOI: 10.1021/acs.organomet.9b00449

Organometallics XXXX, XXX, XXX−XXX

Organometallics

Article

−

Synthesis of L·HBr (8). To a solution of 7 (6.32 g, 14.3 mmol) in

IR (ATR): ν (cm ) = 3144 (w), 3110 (m), 3082 (w), 3002 (vw),

glacial acetic acid (50 mL) was added 2,4,6-trimethylaniline (6.0 mL,

2963 (vs), 2922 (vw), 2910 (sh), 2867 (w), 2732 (vw), 1706 (vw),

1639 (vs), 1610 (vw), 1589 (w), 1571 (vw), 1474 (m), 1453 (vw),

1440 (sh), 1414 (w), 1391 (vw), 1382 (sh), 1359 (s), 1314 (sh),

1302 (w), 1273 (vw), 1246 (w), 1220 (vs), 1179 (w), 1146 (w), 1114

(m), 1080 (w), 1059 (w), 1035 (vw), 996 (vw), 963 (vw), 936 (vw),

894 (vw), 853 (m), 834 (vw), 807 (m), 766 (vs), 756 (sh), 683 (vw),

656 (w), 631 (w), 575 (w), 556 (w), 506 (vw), 467 (vw).

Synthesis of [AuI(L)] (10). In air, to a solution of [AgBr(L)] (9)

(250 mg, 0.375 mmol) in acetone (10 mL) was added a solution of

[AuCl(tht)] (120 mg, 0.375 mmol) in acetone (5 mL) under

protection against light. A white precipitate appeared instantaneously

and the resulting suspension was stirred for 1 h and ﬁltered. A

solution of KI (62 mg, 0.375 mmol) in acetone was added to the

ﬁltrate, leading to the formation of a white suspension which was

stirred for 2 h at room temperature. Filtration of the resulting

suspension and evaporation of the solvent aﬀorded [AuI(L)] (10) as

a light yellow powder. Yield: 298 mg (0.371 mmol), 99%. Single

crystals suitable for X-ray diﬀraction studies were obtained by slow

evaporation of an acetone solution of the complex. Anal. Calcd for

.80 g, 42.9 mmol), and the resulting mixture was heated to reﬂux for

h. After evaporation of the volatiles under reduced pressure, the

resulting solid was redissolved in CH Cl and successively washed

with a 10% aqueous K CO solution and a saturated aqueous NaBr

solution. The organic phase was dried over MgSO and evaporated

under reduced pressure. The resulting brown-green solid was washed

several times with hot toluene to remove N-mesitylacetamide formed

as a side-product, further washed with pentane, and dried in vacuo to

aﬀord a beige powder. Yield: 6.50 g (11.6 mmol), 81%. In some cases,

traces of unreacted 7 were observed in the crude product (ca. 10%).

Puriﬁcation of 8 was then performed by crystallization from CH Cl /

pentane. Single crystals suitable for X-ray diﬀraction studies were

obtained by slow diﬀusion of pentane in a CH Cl solution of the

product. Anal. Calcd for C H BrN (559.60): C, 68.68; H, 7.03; N,

0.01. Found: C, 68.97; H, 6.57; N, 9.95. H NMR (400.30 MHz,

CDCl ): δ [ppm]: 10.51 (t, J = 1.5 Hz, 1H, CH_i_m_i_d), 8.37 (dd,

J_H_H= 7.9 Hz, J = 0.9 Hz, 1H, CH ), 8.09−8.02 (m, 2H, CH

CH_i_m_i_d), 7.88 (t, J = 7.8 Hz, 1H, CH ), 7.53 (t, J = 7.8 Hz,

H, p-CH_D_i_P_P), 7.30 (d, J_H_H= 7.8 Hz, 2H, m-CH_D_i_P_P), 7.16 (t, J

J_H_H≈ 1.8 Hz, 1H, CH_i_m_i_d), 6.88 (br s, 2H, CH_m_e_s), 6.36 (s, 2H,

CH N), 2.29 (sept, J = 6.9 Hz, 2H, CH(CH ) ), 2.28 (s, 3H, p-

pyr

≈

38AuIN

(802.55): C, 47.89; H, 4.77; N, 6.98. Found: C, 47.27;

H, 4.26; N, 6.87. H NMR (400.30 MHz, CDCl

): δ [ppm]: 8.38 (d,

JHH = 7.8 Hz, 1H, m-CHpyr), 7.87 (t, JHH = 7.8 Hz, 1H, p-CHpyr),

3 2

), 2.06 (s, 3H, C(N)CH ), 1.97 (s, 6H, o-CH₃_m_e_s), 1.21 (d,

7.53 (d, J = 7.6 Hz, 1H, m-CH ), 7.47 (t, J = 7.8 Hz, 1H, p-

mes

HH pyr HH

J_H_H= 6.9 Hz, 6H, CH(CH ) ), 1.11 (d, J_H_H= 6.9 Hz, 6H,

CH(CH ) ). C{ H} NMR (100.66 MHz, CDCl ): δ [ppm]: 166.3

CHDiPP), 7.39 (d, JHH = 1.4 Hz, 1H, CHimid), 7.25 (d, overlapping

3 3

with solvent signal, JHH ≈ 7.8 Hz, ca. 2H, m-CHDiPP), 6.95 (d, JHH

1.9 Hz, 1H, CHimid), 6.90 (s, 2H, m-CHmes), 5.70 (s, 2H, CH ), 2.43

), 2.30 (s, 3H, p-CH3 mes), 2.15

(

C(N)CH ), 156.5 (C_a_r_o_m), 151.8 (C_a_r_o_m), 146.0 (C_a_r_o_m), 145.5

C_a_r_o_m), 138.7 (CH_i_m_i_d), 138.3 (CH_p_y_r), 132.6 (C_a_r_o_m), 132.2

CH_D_i_P_P), 130.2 (C_a_r_o_m), 128.7 (CH_m_e_s), 125.5 (CH_i_m_i_d/CH_p_y_r),

25.2 (C_a_r_o_m), 124.9 (CH_D_i_P_P), 123.9 (CH_p_y_r/CH_i_m_i_d), 123.7 (CH_i_m_i_d),

(sept, JHH = 6.8 Hz, 2H, CH(CH

(s, 3H, CCH ), 2.01 (s, 6H, o-CH3 mes), 1.28 (d, JHH = 6.8 Hz, 6H,

CH(CH ), 1.10 (d, JHH = 6.9 Hz, 6H, CH(CH

(100.67 MHz, CDCl ): δ [ppm]: 184.0 (CNHC), 167.0 (C(N)CH

)

3 2

). ¹³C{ H} NMR

)

3 2

21.6 (CH ), 54.1 (CH N), 28.9 (CH(CH ) ), 24.5 (CH(CH ) ),

pyr

3 2

4.4 (CH(CH ) ), 20.8 (p-CH₃_m_e_s), 18.0 (o-CH₃_m_e_s), 16.4 (CCH₃).

156.6 (Carom), 153.6 (Carom), 146.1 (Carom), 145.8 (Carom), 137.8 (p-

CHpyr), 134.0 (Carom), 132.5 (Carom), 130.7 (p-CHDiPP), 128.7 (m-

CHmes), 125.3 (Carom), 124.3 (m-CHDiPP), 123.4 (m-CHpyr + CHimid),

−1

IR (ATR): ν

(cm ) = 3135 (vw), 3093 (vw), 3019 (m), 2963 (vs),

941 (s), 2909 (sh), 2871 (w), 2807 (vw), 2720 (vw), 1783 (vw),

701 (vw), 1671 (vw), 1641 (s), 1588 (w), 1571 (w), 1556 (vw),

536 (s), 1477 (m), 1448 (w), 1405 (vw), 1388 (vw), 1361 (s), 1335

121.3 (CHimid), 121.0 (m-CHpyr), 56.0 (CH

24.47 (CH(CH ), 24.44 (CH(CH ), 20.8 (p-CH3 mes), 18.0 (o-

CH3 mes), 16.5 (C(N)CH ). IR (ATR): ν

2 3 2

), 28.5 (CH(CH ) ),

)

3 2

−

(vw), 1313 (w), 1299 (sh), 1273 (vw), 1244 (vw), 1215 (m), 1185

(vs), 1147 (w), 1114 (m), 1083 (vw), 1058 (vw), 1024 (vw), 998

(vw), 939 (vw), 899 (w), 853 (m), 830 (vw), 816 (w), 787 (w), 768

(m), 728 (vw), 674 (vw), 650 (vw), 630 (vw), 579 (vw), 559 (vw),

(cm ) = 3172 (vw), 3140

(vw), 2961 (m), 2924 (vw), 2910 (sh), 2865 (w), 1702 (vw), 1647

(m), 1588 (w), 1575 (vw), 1561 (w), 1475 (m), 1458 (w), 1443

(vw), 1423 (w), 1405 (sh), 1385 (vw), 1362 (s), 1313 (m), 1277

(vw), 1255 (m), 1231 (vw), 1211 (m), 1194 (w), 1179 (vw), 1147

(w), 1115 (m), 1084 (w), 1057 (w), 1042 (vw), 1013 (vw), 996 (w),

970 (sh), 959 (vw), 938 (w), 850 (s), 830 (vw), 809 (m), 800 (sh),

781 (w), 767 (w), 729 (vs), 704 (vw), 688 (m), 651 (w), 633 (w),

63 (vw). MS (ESI ): m/z (%) 479.31 (100) [M − Br] , i.e.,

32 39 4

[

C H N ] with the corresponding isotopic pattern.

Synthesis of [AgBr(L)] (9). L·HBr (8) (0.500 g, 0.890 mmol) and

Ag O (0.113 g, 0.490 mmol) were charged in a Schlenk ﬂask,

acetonitrile (30 mL) was added and the mixture was stirred for ca. 2

days at 40 °C under exclusion of light. After evaporation of the solvent

under reduced pressure, the remaining slurry was extracted twice with

CH Cl and the resulting suspension was ﬁltered over Celite and

603 (vw), 557 (w), 507 (vw), 469 (w), 419 (vw). MS (EI , 280 °C):

m/z (%) 801.16 (<1) [M − H] , i.e., [C32

37AuIN

] , 675.27 (8) [M

−

I] , i.e., [C H AuN ] , with the corresponding isotopic pattern.

Synthesis of [Au(C F )(L)] (11). To a solution of [AgBr(L)] (9)

32 38 4

(

[

0.165 g, 0.247 mmol) in THF (10 mL) was added a solution of

Au(C F )(tht)] (0.112 g, 0.247 mmol) in the same solvent (10 mL),

concentrated to ca. 1−2 mL. Addition of Et O precipitated 9 as a

beige powder that was isolated by ﬁltration and dried under vacuum.

Yield: 0.540 g (0.810 mmol), 91%. Single crystals suitable for X-ray

diﬀraction studies were obtained by slow diﬀusion of heptane in a

CHCl₃solution of the complex. Anal. Calcd for C H AgBrN

6 5

and the resulting mixture was stirred at room temperature for 2 h

under exclusion of light. After evaporation of the solvent under

reduced pressure, the remaining slurry was extracted with Et O and

ﬁltered over Celite. Slow evaporation of the solvent aﬀorded 11 as

yellow crystals suitable for X-ray diﬀraction. Yield of the crystals:

(

666.46): C, 57.67; H, 5.75; N, 8.41. Found: C, 57.33; H, 5.41; N,

.49. H NMR (400.30 MHz, CDCl ): δ [ppm]: 8.36 (d, J = 7.8

3 HH

.111 g (0.132 mmol), 53%. Anal. Calcd for C H AuF N (842.71):

Hz, 1H, m-CH_p_y_r), 7.85 (t, J = 7.8 Hz, 1H, p-CH ), 7.46 (t, J

38 38 5 4

pyr

C, 54.16; H, 4.55; N, 6.65. Found: C, 54.62; H, 4.12; N, 6.51. H

NMR (400.30 MHz, CDCl ): δ [ppm]: 8.35 (dd, J = 7.9 Hz, 1H,

m-CH ), 7.86 (t, J = 7.8 Hz, 1H, p-CH ), 7.63 (dd, J = 7.6

7.8 Hz, 1H, p-CH ), 7.40 (dd, J = 7.6 Hz, J = 0.7 Hz, 1H,

DiPP HH HH

m-CH_p_y_r), 7.37 (d, J = 1.1 Hz, 1H, CH_i_m_i_d), 7.25 (d overlapping

with solvent signal, J ≈ 7.6 Hz, ca. 2H, m-CH_D_i_P_P), 7.02 (d, J

pyr

Hz, 1H, m-CH ), 7.47 (t, J ⁼⁷^.⁸^H^z^,¹^H^,^p^-^C^HDiPP), 7.41 (d,

.6 Hz, 1H, CH ), 6.89 (s, 2H, m-CH ), 5.60 (s, 2H, CH ), 2.40

pyr

imid

mes

(sept, J = 6.6 Hz, 2H, CH(CH ) ), 2.29 (s, 3H, p-CH₃_m_e_s), 2.11

HH = 1.3 Hz, 1H, CHimid), 7.26 (d overlapping with solvent signal,

3 2

(

s, 3H, C(N)CH ), 1.99 (s, 6H, o-CH

H, CH(CH ) ), 1.10 (d, J = 6.8 Hz, 6H, CH(CH ) ). C{ H}

), 1.21 (d, J = 6.8 Hz,

HH ≈ 7.8 Hz, ca. 2H, m-CHDiPP), 6.98 (d, JHH = 1.8 Hz, 1H,

3 mes

CH_i_m_i_d), 6.90 (s, 2H, m-CH ), 5.72 (s, 2H, CH ), 2.45 (sept, J

mes

NMR (75.47 MHz, CDCl ): δ [ppm]: 184.1 (br d, J

Hz, C_N_H_C), 166.9 (C(N)CH ), 156.8 (o-C ), 153.8 (o-C ), 146.1

≈ 250

6.8 Hz, 2H, CH(CH ) ), 2.30 (s, 3H, p-CH₃_m_e_s), 2.16 (s, 3H,

3 2

C‑107/109Ag

C(N)CH ), 2.00 (s, 6H, o-CH

), 1.27 (d, J = 6.8 Hz, 6H,

3 mes HH

pyr

(o-C_m_e_s), 145.8 (o-C_D_i_P_P), 137.9 (p-CH ), 134.7 (i-C_D_i_P_P), 132.5 (p-

CH(CH ) ), 1.12 (d, J = 6.9 Hz, 6H, CH(CH ) ). C{ H} NMR

pyr

3 2 HH 3 2

C_m_e_s), 130.7 (p-CH_D_i_P_P), 128.7 (m-CH_m_e_s), 125.3 (i-C_m_e_s), 124.4 (m-

(100.67 MHz, CDCl ): δ [ppm]: 190.8 (C_N_H_C), 167.1 (C(N)CH₃),

156.6 (C_a_r_o_m), 154.1 (C_a_r_o_m), 146.2 (C_a_r_o_m), 146.0 (C_a_r_o_m), 137.9 (p-

CH_D_i_P_P), 124.2 (CH_i_m_i_d), 123.1 (m-CH ), 121.8 (CH_i_m_i_d), 121.0 (m-

pyr

CH ), 57.0 (CH ) 28.4 (CH(CH ) ), 24.7 (CH(CH ) ), 24.5

CH ), 134.3 (C_a_r_o_m), 132.5 (C_a_r_o_m), 130.5 (p-CH_D_i_P_P), 128.7 (m-

CH_m_e_s), 125.3 (C_a_r_o_m), 124.1 (m-CH_D_i_P_P), 123.7 (m-CH_p_y_r), 123.5

pyr

(

CH(CH ) ), 20.9 (p-CH₃_m_e_s), 18.0 (o-CH₃_m_e_s), 16.5 (C(N)CH₃).

DOI: 10.1021/acs.organomet.9b00449

Organometallics XXXX, XXX, XXX−XXX

Organometallics

Article

(

CH_i_m_i_d), 121.4 (CH_i_m_i_d), 121.0 (m-CH_p_y_r), 56.2 (CH ), 28.6

CH₃_m_e_s), 1.95 (s, 6H, CCH ), 1.01 (d, ³J_H_H= 6.8 Hz, 12H,

CH(CH ) ), 24.4 (CH(CH ) ), 24.3 (CH(CH ) ), 20.9 (p-

CH(CH ) ), 0.81 (d, J = 6.8 Hz, 12H, CH(CH ) ). C{ H}

3 2 HH 3 2

CH₃_m_e_s), 18.0 (o-CH₃_m_e_s), 16.5 (C(N)CH ). The carbon atoms

corresponding to the C F group could not be observed. F NMR

NMR (100.67 MHz, CDCl ): δ [ppm]: 185.4 (C_N_H_C), 166.8

(C(N)CH ), 156.1 (C_a_r_o_m), 153.4 (C_a_r_o_m), 146.10 (C_a_r_o_m), 146.04

(

−

376.62 MHz, CDCl ): δ [ppm]: −116.1 to −116.3 (m, 2F, o-CF),

(C_a_r_o_m), 137.6 (p-CH ), 133.9 (C_a_r_o_m), 132.5 (C_a_r_o_m), 130.7 (p-

pyr

160.4 (t, J = 19.8 Hz, 1F, p-CF), −163.3 to −163.5 (m, 2F, m-

CH_D_i_P_P), 128.7 (m-CH_m_e_s), 125.1 (C_a_r_o_m), 124.1 (m-CH_D_i_P_P), 124.0

(CH_i_m_i_d), 123.4 (CH_i_m_i_d), 123.2 (m-CH ), 120.6 (m-CH ), 55.1

−1

CF). IR (ATR): ν

(cm ) = 3174 (w), 3146 (w), 2969 (sh), 2951

pyr

(w), 2923 (w), 2862 (m), 1649 (s), 1633 (sh), 1590 (m), 1573 (w),

(CH ), 28.3 (CH(CH ) ), 24.4 (CH(CH ) ), 24.2 (CH(CH ) ), 20.9

2 3 2 3 2 3 2

(p-CH₃_m_e_s), 18.0 (o-CH₃_m_e_s), 16.1 (C(N)CH ). IR (ATR): ν (cm )

−

499 (vs), 1475 (s), 1450 (vs), 1436 (m), 1421 (w), 1411 (sh), 1364

(s), 1351 (sh), 1314 (m), 1254 (m), 1233 (w), 1213 (m), 1187 (w),

= 3167 (w), 3133 (w), 3100 (vw), 2963 (s), 2925 (w), 2869 (w),

1700 (m), 1642 (m), 1588 (m), 1573 (w), 1557 (vw), 1492 (vw),

1474 (m), 1458 (w), 1443 (vw), 1419 (w), 1385 (w), 1362 (s), 1312

(m), 1255 (w), 1215 (m), 1194 (vw), 1181 (vw), 1147 (w), 1115

(w), 1059 (s), 1032 (w), 994 (w), 961 (w), 937 (w), 854 (m), 806

(m), 776 (w), 761 (w), 741 (w), 731 (vw), 709 (vw), 670 (w), 652

(w), 633 (w), 600 (vw), 586 (vw), 558 (w), 520 (w), 469 (vw), 422

147 (w), 1117 (m), 1078 (w), 1062 (vw), 1051 (s), 1014 (w), 996

(

w), 952 (vs), 856 (m), 803 (w), 792 (m), 780 (w), 763 (m), 730

m), 690 (w), 654 (w), 634 (vw), 557 (w), 466 (vw).

Synthesis of [Ag(L) ](BF ) (12). To a Schlenk ﬂask charged with

[

AgBr(L)] (9) (400 mg, 0.600 mmol) and AgBF (58.4 mg, 0.300

mmol) was added acetonitrile (20 mL) and the reaction mixture was

stirred overnight at room temperature under exclusion of light. The

resulting suspension was ﬁltered over Celite and concentrated to ca.

(vw). MS (ESI ): m/z (%) 1153.58 (100) [M − BF ] , i.e.,

[C H AuN ] , 479.32 (7) [L+H] , i.e., [C H N ] , with the

32 39

−2 mL. Addition of Et O precipitated 12 as a yellow powder that

corresponding isotopic pattern.

Synthesis of [(LH) Cu](BF ) (14). To a Schlenk ﬂask charged

was isolated by ﬁltration and dried under vacuum. Yield: 315 mg

0.273 mmol), 91% based on the ligand. Crystals of 12 suitable for X-

4 3

(

with L·HBr (8) (73.0 mg, 0.130 mmol), AgBF (38.0 mg, 0.195

ray diﬀraction studies were obtained by slow diﬀusion of Et O in a

mmol) and [CuBr(SMe )] (13.4 mg, 0.065 mmol) was added

acetonitrile (10 mL) and the reaction mixture was stirred overnight at

room temperature under exclusion of light. The resulting suspension

was ﬁltered over Celite and concentrated to ca. 4−5 mL. Brown

crystals of 14 suitable for X-ray diﬀraction studies were obtained by

64 76

slow vapor diﬀusion of Et O in the acetonitrile solution of the

complex. Yield of the crystals: 50 mg (0.039 mmol), 60% based on the

ligand. Anal. Calcd for C H B CuF N (1283.34): C, 59.90; H,

64 78

6.13; N, 8.73. Found: C, 59.37; H, 5.85; N, 8.52. H NMR (400.30

MHz, CD CN): δ [ppm]: 8.83 (t, J = 1.6 Hz, 2H, CH_i_m_i_d), 8.29

(d, J = 7.8 Hz, 2H, m-CH ), 8.13 (t, J = 7.8 Hz, 2H, p-CH_p_y_r),

HH pyr HH

7.79 (t, J ≈ J ≈ 1.8 Hz, 2H, CH ), 7.65−7.56 (m, 6H, CH_i_m_i_d

imid

+ m-CH_p_y_r+ p-CH ), 7.42 (d, J = 7.8 Hz, 4H, m-CH ), 6.95

DiPP HH DiPP

(s, 4H, m-CH_m_e_s), 5.75 (s, 4H, CH ), 2.35 (sept, J = 6.8 Hz, 4H,

(

C_a_r_o_m), 146.0 (C_a_r_o_m), 137.7 (p-CH_p_y_r), 134.7 (C_a_r_o_m), 132.5

CH(CH ) ), 2.28 (s, 6H, p-CH

overlapping with solvent signal, ca. 12H, o-CH

3 mes

C_a_r_o_m), 130.5 (p-CH ), 128.7 (m-CH_m_e_s), 125.1 (C_a_r_o_m), 124.1

DiPP

m-CH_D_i_P_P), 124.0 (d, J_C_‑₁₀₇_/₁₀₉_A_g= 6.0 Hz, CH_i_m_i_d), 123.3 (m-

6.8 Hz, 12H, CH(CH ) ), 1.15 (d, J = 6.8 Hz, 12H, CH(CH ) ).

3 2 HH 3 2

C{ H} NMR (100.67 MHz, CD CN): δ [ppm]: 168.4 (C(N)CH ),

3 3

CH ), 123.2 (d, J

= 5.5 Hz, CH_i_m_i_d), 120.6 (m-CH_p_y_r),

pyr

C‑107/109Ag

6.2 (CH ), 28.2 (CH(CH ) ), 24.6 (CH(CH ) ), 24.1 (CH(CH ) ),

154.9 (C_a_r_o_m), 153.2 (C_a_r_o_m), 146.5 (C_a_r_o_m), 145.8 (C_a_r_o_m), 140.4 (p-

3 2

0.9 (p-CH _m_e_s), 18.0 (o-CH₃_m_e_s), 16.1 (C(N)CH ). IR (ATR): ν

CH ), 138.6 (CH_i_m_i_d), 134.6 (C_a_r_o_m), 132.9 (p-CH_D_i_P_P/m-CH_p_y_r),

pyr

−

(

cm ) = 3159 (w), 3132 (w), 2964 (m), 2928 (vw), 2869 (w), 1648

s), 1587 (w), 1574 (w), 1557 (vw), 1475 (m), 1461 (vw), 1453 (sh),

440 (w), 1422 (m), 1386 (w), 1363 (s), 1312 (w), 1255 (m), 1220

w), 1198 (w), 1183 (w), 1147 (m), 1113 (s), 1085 (sh), 1071 (m),

061 (sh), 1035 (m), 1012 (sh), 993 (m), 957 (w), 935 (w), 906

vw), 854 (s), 810 (vs), 778 (s), 766 (w), 754 (m), 742 (w), 689 (w),

131.2 (C_a_r_o_m), 129.7 (m-CH_m_e_s), 127.0 (C_a_r_o_m), 126.4 (CH_i_m_i_d), 126.0

(m-CH /p-CH_D_i_P_P), 125.6 (m-CH_D_i_P_P), 125.3 (CH_i_m_i_d), 124.1 (m-

pyr

CH ), 55.4 (CH ), 29.4 (CH(CH ) ), 24.3 (CH(CH ) ), 24.2

pyr

3 2

(CH(CH ) ), 20.8 (p-CH₃_m_e_s), 17.9 (o-CH₃_m_e_s), 16.8 (C(N)CH₃).

3 2

−

IR (ATR): ν (cm ) = 3174 (w), 3136 (w), 3097 (vw), 2967 (m),

(

2929 (w), 2870 (w), 1617 (w), 1594 (m), 1565 (w), 1548 (m), 1480

(w), 1464 (w), 1438 (w), 1368 (m), 1310 (w), 1283 (w), 1261 (vw),

1245 (vw), 1218 (w), 1193 (m), 1156 (vw), 1106 (sh), 1052 (s),

1033 (w), 1017 (sh), 958 (w), 936 (vw), 854 (w), 807 (m), 759 (m),

735 (sh), 670 (w), 639 (vw), 619 (vw), 561 (w), 520 (m), 458 (w).

Synthesis of [Ag (L) ](BF ) (15). To a Schlenk ﬂask charged

49 (m), 633 (w), 601 (w), 569 (vw), 557 (w), 519 (w), 477 (w),

16 (vw). MS (ESI ): m/z (%) 1063.52 (100) [M-BF ] , i.e.,

[

C H AgN ] , 585.21 (7) [Ag(L)] i.e. [C H AgN ] , 479.32

64 76 8 32 38 4

(53) [L + H] , i.e., [C H N ] , with the corresponding isotopic

32 39 4

pattern.

4 2

Synthesis of [Au(L) ](BF ) (13). To a Schlenk ﬂask charged with

with [AgBr(L)] (9) (200 mg, 0.300 mmol) and AgBF (58.4 mg,

[

AgBr(L)] (9) (200 mg, 0.300 mmol), [AuCl(tht)] (48.1 mg, 0.150

0.300 mmol) was added acetonitrile (15 mL) and the reaction

mixture was stirred overnight at room temperature under exclusion of

light. The resulting suspension was ﬁltered over Celite and

mmol) and AgBF (29.2 mg, 0.150 mmol) was added acetonitrile (15

mL) and the reaction mixture was stirred overnight at room

temperature under exclusion of light. The resulting suspension was

ﬁltered over Celite and concentrated to ca. 1−2 mL. Addition of Et O

precipitated 13 as a yellow powder that was isolated by ﬁltration and

dried under vacuum. Yield: 155 mg (0.125 mmol), 83% based on the

ligand. Crystals of 13 suitable for X-ray diﬀraction studies were

obtained by slow evaporation of a CH Cl solution of the complex.

concentrated to ca. 1−2 mL. Addition of Et O precipitated 15 as a

yellow powder that was isolated by ﬁltration and dried under vacuum.

Yield: 160 mg (0.119 mmol), 79% based on the ligand. Crystals

suitable for X-ray diﬀraction studies were obtained by slow vapor

diﬀusion of Et O in an acetonitrile solution of the complex. Anal.

Calcd for C H Ag B F N (1346.71): C, 57.08; H, 5.69; N, 8.32.

64 76

Anal. Calcd for C H AuBF N (1241.14): C, 61.94; H, 6.17; N,

Found: C, 57.60; H, 5.75; N, 8.41. H NMR (400.30 MHz, CD CN):

.03. Found: C, 61.40; H, 5.55; N, 9.10. H NMR (400.30 MHz,

δ [ppm]: 8.14−8.02 (m, 4H, 2 x CH ), 7.80 (t, J = J

= 1.8

HAg

pyr

CDCl ): δ [ppm]: 8.30 (d, J = 7.7 Hz, 2H, m-CH ), 7.80 (t, J

Hz, 2H, CH ), 7.49 (t, J = 7.8 Hz, 2H, p-CH_D_i_P_P), 7.41 (t, J

pyr

imid HH HH

7.8 Hz, 2H, p-CH ), 7.41 (d, J = 1.8 Hz, 2H, CH_i_m_i_d), 7.37 (t,

= J = 1.7 Hz, 2H, CH_i_m_i_d), 7.40−7.35 (m, 2H, CH ), 7.19 (br s,

pyr

HAg

pyr

J_H_H= 7.8 Hz, 2H, p-CH ), 7.28 (d, J = 7.6 Hz, 2H, m-CH ),

Δν ≈ 60 Hz, 4H, m-CH_D_i_P_P), 6.69 (s, 4H, m-CH ), 5.73 (s, 4H,

DiPP

pyr

1/2

mes

.09 (d, J = 7.8 Hz, 4H, m-CH_D_i_P_P), 6.93 (d, J = 1.8 Hz, 2H,

CH ), 2.67 (br s, Δν ≈ 100 Hz, 2H, CH(CH ) ), 2.20 (s, 6H, p-

1/2

3 2

CH_i_m_i_d), 6.89 (s, 4H, m-CH ), 5.39 (s, 4H, CH ), 2.30 (s, 6H, p-

CH₃_m_e_s), 2.25 (sept, J = 6.9 Hz, 4H, CH(CH ) ), 1.97 (s, 12H, o-

), 2.03 (s, 6H, CCH ), 1.46−0.82 (br m, 32H, o-CH

mes

3 mes

CH(CH₃)₂+ CH(CH ) ), 0.02 (br s, Δν

≈ 100 Hz, 6H,

1/2

DOI: 10.1021/acs.organomet.9b00449

Organometallics XXXX, XXX, XXX−XXX

Organometallics

Article

CH(CH ) ). C{ H} NMR (100.67 MHz, CD CN): δ [ppm]: 183.7

CH_D_i_P_P), 55.5 (CH ), 28.7 (CH(CH ) ), 27.8 (CH(CH ) ), 25.1

3 2

(

two doublets, J

= 244 Hz, J

= 282 Hz, C_N_H_C), 171.9

(CH(CH ) ), 24.55 (CH(CH ) ), 24.51 (CH(CH ) ), 23.9 (CH-

C‑107Ag

C‑109Ag

3 2 3 2 3 2

C(N)CH ), 159.1 (C_a_r_o_m), 149.0 (C_a_r_o_m), 146.6 (2 x C_a_r_o_m), 144.4

C_a_r_o_m), 142.0 (CH ), 136.4 (C_a_r_o_m), 136.0 (C_a_r_o_m), 131.6 (p-

CH ), 129.8 (br, m-CH_m_e_s), 128.2 (CH_p_y_r), 126.7 (CH ), 125.7

d, J_C_‑₁₀₇_/₁₀₉_A_g= 7.2 Hz, CH_i_m_i_d), 125.0 (m-CH_D_i_P_P), 124.6 (d,

(CH ) ), 20.9 (CH₃_m_e_s), 18.9 (CH₃_m_e_s/C(N)CH ), 16.8 (C(N)

3 2 3

CH /CH₃_m_e_s), 16.2 (CH₃_m_e_s) (only the signals for the major isomer

pyr

−

(A) are reported). IR (ATR): ν (cm ) = 3166 (w), 3145 (vw), 3133

(w), 3101 (w), 3078 (vw), 2965 (s), 2925 (w), 2868 (w), 2737 (vw),

1620 (m), 1593 (vs), 1564 (w), 1480 (w), 1462 (m), 1443 (m), 1406

DiPP

pyr

(

J_C_‑₁₀₇_/₁₀₉_A_g= 7.2 Hz, CH_i_m_i_d), 59.4 (CH ), 29.0 (CH(CH ) ), 24.3

3 2

(

m), 1374 (w), 1364 (sh), 1320 (w), 1286 (s), 1269 (sh), 1247 (m),

216 (m), 1193 (w), 1179 (w), 1156 (w), 1112 (w), 1082 (sh), 1054

(

br, CH(CH ) ), 20.7 (p-CH₃_m_e_s), 17.9 (o-CH

), 17.2 (d,

(cm ) = 3174 (w),

3 mes

−1

J_C_‑₁₀₇_/₁₀₉_A_g= 2.4 Hz, C(N)CH ). IR (ATR): ν

(

s), 1022(m), 1001 (sh), 958 (w), 936 (w), 885 (w), 855 (s), 806

vs), 779 (m), 762 (w), 751 (w), 738 (w), 689 (w), 654 (vw), 640

w), 606 (vw), 590 (vw), 562 (w), 520 (w), 492 (vw), 463 (vw). UV/

(

134 (w), 3093 (vw), 3071 (vw), 2965 (vs), 2925 (m), 2870 (m),

733 (vw), 1644 (w), 1625 (m), 1593 (vs), 1559 (vw), 1480 (sh),

462 (m), 1444 (s), 1409 (s), 1388 (w), 1370 (s), 1335 (w), 1296

m), 1271 (m), 1249 (s), 1216 (m), 1193 (w), 1155 (w), 1109 (sh),

088 (sh), 1059 (m), 1047 (vw), 1030 (w), 999 (sh), 958 (m), 935

vw), 915 (vw), 860 (s), 805 (s), 776 (s), 759 (s), 738 (w), 686 (w),

55 (w), 640 (w), 600 (vw), 584 (vw), 562 (w), 520 (w), 487 (vw),

64 (vw), 428 (vw). UV/vis (CH Cl ): λ

cm ]) = 393 (980), 285 (15 000). MS (ESI ): m/z (%) 1063.52

max

−1

vis (CH Cl ): λ [nm] (ε [L mol cm ]) = 558 (sh, 1300), 464

(

2600), 320 (sh, 7100), 278 (23 000). MS (ESI ): m/z (%) 541.24

100) [M − 2(BF )] , i.e., [C H Cu N ] , 479.32 (89) [L + H] ,

(

64 76

i.e., [C H N ] , with the corresponding isotopic pattern.

32 39

max

−1

Synthesis of [AgAu(L) ](BF ) (17). To a Schlenk ﬂask charged

[nm] (ε [L mol

2 4 2

−

with [Au(L) ](BF ) (13) (200 mg, 0.161 mmol) and AgBF (31.4

2 4 4

mg, 0.161 mmol) was added acetonitrile (15 mL), and the reaction

mixture was stirred for 2 h at room temperature under exclusion of

light. The resulting solution was ﬁltered over Celite and concentrated

(

62) [M − Ag − 2(BF )] , i.e., [C H AgN ] , 586.21 (100) [M −

64 76

2+ 2+ +

[

(BF )] , i.e., [C H Ag N ] , 479.32 (23) [L + H] , i.e.,

4 64 76 2 8

C H N ] , with the corresponding isotopic pattern.

Synthesis of [Cu (L) ](BF ) (16). To a suspension of L·HBr (8)

300 mg, 0.536 mmol) in THF (10 mL) was added, at −78 °C, a

solution of [CuMes] (98 mg, 0.536 mmol) in THF (10 mL). The

resulting clear brown-red solution was allowed to reach room

temperature and stirred for 1 h. All the volatiles were evaporated in

vacuo and the solid residue was redissolved in acetonitrile (10 mL).

Addition of a solution of AgBF (104 mg, 0.536 mmol) in acetonitrile

10 mL) led to the formation of a white precipitate. After stirring for

an additional 2 h, the solution was ﬁltered over Celite and

32 39 4

to ca. 1−2 mL. Addition of Et O precipitated 17 as a yellow powder

4 2

that was isolated by ﬁltration and dried under vacuum. Crystals

suitable for X-ray diﬀraction studies were obtained by slow diﬀusion

(

of Et O in an acetonitrile solution of the complex. Yield of the

crystals: 130 mg (0.091 mmol), 56%. Anal. Calcd for

C H AgAuB F N (1435.81): C, 53.54; H, 5.34; N, 7.80. Found:

C, 53.86; H, 5.41; N, 7.40. H NMR (400.30 MHz, CDCl ): δ

ppm]: 8.05 (d, J = 7.8 Hz, 2H, m-CH ), 8.00 (d, J = 1.9 Hz,

H, CH_i_m_i_d), 7.97 (t, J = 8.0 Hz, 2H, p-CH ), 7.38 (t, J = 7.8

Hz, 2H, p-CH_D_i_P_P), 7.10 (d, J = 7.6 Hz, 2H, m-CH ), 6.99−6.89

m, 6H, m-CH_D_i_P_P+ m-CH_p_y_r+ m-CH_m_e_s), 6.94 (d, J = 1.8 Hz,

H, CH_i_m_i_d), 6.70 (s, 2H, m-CH_m_e_s), 5.64 (d, J = 17.6 Hz, A part

of an AB spin system, 2H, CH ), 5.19 (d, J = 17.6 Hz, B part of an

[

HH pyr HH

(

HH pyr HH

DiPP

concentrated to ca. 1−2 mL. Addition of Et O precipitated 16 as

(

an orange-brown powder that was isolated by ﬁltration and dried

under vacuum. Crystals suitable for X-ray diﬀraction studies were

obtained by slow diﬀusion of Et O in a CH Cl solution of the

AB spin system, 2H, CH ), 2.33 (s, 6H, CCH ), 2.32 (s, 6H, o-

complex. Yield of the crystals: 270 mg (0.215 mmol), 80% based on

the ligand. The H NMR of the 16 reveals the presence of two species

in solution, A and B, in a ratio of ca. 1.0:0.6 in CDCl at room

temperature and assigned to the head-to-head and head-to-tail isomers.

Anal. Calcd for C H B Cu F N (1258.07): C, 61.10; H, 6.09; N,

.91. Found: C, 60.92; H, 5.72; N, 8.72. H NMR (400.30 MHz,

^C^H3 mes), 2.31 (s, 6H, o-CH

), 2.25 (sept, J = 6.8 Hz, 2H,

3 mes

CH(CH ) ), 2.02 (sept, J = 6.5 Hz, 2H, CH(CH ) ), 1.25 (s, 6H,

3 2

p-CH₃_m_e_s), 1.03 (d, J = 6.8 Hz, 12H, CH(CH ) ), 0.84 (d, J =

.6 Hz, 6H, CH(CH ) ), 0.68 (d, J = 6.8 Hz, 6H, CH(CH ) ). H

3 2 HH 3 2

NMR (400.30 MHz, CD CN): δ [ppm]: 8.13 (dd, J = 7.9 Hz,

^JHH = 0.7 Hz, 2H, m-CH ), 8.05 (t, J = 7.9 Hz, 2H, p-CH ),

pyr

CDCl ): δ [ppm]: 8.21−8.09 (m, 2.2H, m-CH

+ m-CH

+ p-

pyr

7.54 (d, JHH = 1.8 Hz, 2H, CHimid), 7.43 (t, JHH = 7.8 Hz, 2H, p-

CHDiPP), 7.23 (d, JHH = 1.9 Hz, 2H, CHimid), 7.11 (d, JHH = 7.8 Hz,

CH ), 8.02 (t, J = 7.9 Hz, 1H, p-CH ), 7.98 (d, J = 1.3 Hz,

pyr

(

^.⁶^H^,^C^Himid ), 7.67 (d, J = 7.6 Hz, 0.6H, m-CH ), 7.64 (d, J

HH pyr HH

), 7.40 (t, J = 7.8 Hz, 0.6H, p-CH ), 7.36

DiPP

4H, m-CHDiPP), 7.03 (dd, JHH = 7.8 Hz, JHH = 0.7 Hz, 2H, m-

CHpyr), 6.95 (s, 4H, m-CHmes), 5.24 (s, 4H, CH ), 2.33 (s, 6H, p-

^C^H3 mes), 2.29 (s, 6H, CCH ), 2.11 (br s, Δν ≈ 24 Hz, 4H,

1.6 Hz, 1H, CH

t, J = 7.8 Hz, 1H, p-CH

imid

), 7.17 (dd, J = 7.8 Hz, J = 0.8

DiPP HH HH

1/2

Hz, 0.6H, m-CH

), 7.11 (dd, J = 7.8 Hz, J = 1.2 Hz, 1H, m-

DiPP

HH HH

CH(CH ) ), 1.79 (br s, Δν ≈ 32 Hz, 12H, o-CH

), 1.01 (d,

CH_D_i_P_P^A), 7.03 (d, J = 7.8 Hz, 1H, m-CH ), 6.99 (d, J = 1.5

1/2

3 mes

= 6.8 Hz, 6H,

pyr

= 6.8 Hz, 12H, CH(CH ) ), 0.78 (d,

Hz, 0.6H, CH

), 6.96 (dd, J = 7.9 Hz, J = 1.1 Hz, 0.6H, m-

HH HH

imid

CH_D_i_P_P^B), 6.95 (dd, J = 7.8 Hz, J = 1.2 Hz, 1H, m-CH

CH(CH ). C{ H} NMR (100.67 MHz, CD

(CNHC), 169.6 (C(N)CH

)

CN): δ [ppm]: 187.2

), 157.6 (Carom), 151.0 (Carom), 146.1

DiPP

.87 (s, 1H, m-CH ), 6.85 (d, J = 1.6 Hz, 1H, CH

), 6.63 (s,

imid

mes

.6H, m-CH_m_e_s^A+ m-CH_m_e_s), 6.58 (s, 0.6H, m-CH_m_e_s), 6.00 (d,

(Carom), 145.5 (Carom), 141.6 (p-CHpyr), 135.8 (Carom), 134.6 (Carom),

131.5 (p-CHDiPP), 129.9 (m-CHmes), 127.4 (Carom), 126.0 (m-CHpyr),

J_H_H= 15.8 Hz, A part of an AB spin system, 0.6H, CH ), 5.89 (d,

²⁵^.⁴⁽^C^Himid⁾^,¹²⁵^.³⁽^C^Himid⁾^,¹²⁵^.¹⁽^m^-^C^HDiPP⁾^,¹²⁴^.⁸⁽^m^-^C^Hpyr⁾^,

J_H_H= 15.9 Hz, B part of an AB spin system, 0.6H, CH ), 5.43 (d,

7.4 (CH ), 29.1 (CH(CH ) ), 24.9 (CH(CH ) ), 24.4 (CH(CH ) ),

3 2

2_J= 18.4 Hz, A part of an AB spin system, 1H, CH ), 4.85 (d, J

20.8 (p-CH _m_e_s), 18.1 (o-CH₃_m_e_s), 17.7 (C(N)CH ). IR (ATR): ν

3 3

18.3 Hz, B part of an AB spin system 1H, CH ), 2.70 (sept, J

−1

(cm ) = 3170 (sh), 3130 (w), 2964 (s), 2927 (w), 2869 (w), 1639

(w), 1619 (sh), 1591 (s), 1560 (w), 1475 (sh), 1461 (m), 1443 (sh),

1418 (w), 1366 (w), 1337 (w), 1309 (w), 1297 (sh), 1255 (m), 1214

(m), 1196 (vw), 1154 (w), 1124 (sh), 1057 (m), 1029 (m), 997 (w),

962 (sh), 937 (sh), 851 (w), 801 (m), 784 (w), 758 (m), 731 (sh),

.4 Hz, 0.6H, CH(CH ) ), 2.38−2.23 (m, 10H, C(N)CH (3H) +

3 2

^o^-^C^H3

(

mes

(6H) + CH(CH ) (1H)), 2.17 (s, 1.8H, CH

), 2.08

3 mes

sept, ³^JHH = 6.8 Hz, 0.6H, CH(CH ) ), 2.05−1.94 (m, 2.8H,

A B 3

^C^H⁽^C^H3⁾

+ C(N)CH ), 1.12 (d,

= 6.8 Hz, 1.8H,

CH(CH ) ), 1.11 (s, 1.8H, CH

^C^H³mes (3H) + CH(CH )⁽⁶^H⁾⁺^C^H3 mes (1.8H) + CH(CH )

3.4H)), 0.84 (d, J = 6.8 Hz, 3H, CH(CH ) ), 0.69 (d, J = 6.9

Hz, 3H, CH(CH ) ), 0.00 (d, J = 6.9 Hz, 1.7H, CH(CH ) ).

C{ H} NMR (100.67 MHz, CDCl ): δ [ppm]: 177.6 (C_N_H_C), 168.7

C(N)CH ), 156.3 (C_a_r_o_m), 152.4 (C_a_r_o_m), 146.2 (C_a_r_o_m), 144.6

), 1.06−0.96 (m, 14.2H, p-

3 mes

704 (w), 638 (vw), 561 (w), 519 (w), 458 (vw). UV/vis (CH Cl ):

2 2

max

−1

[nm] (ε [L mol cm ]) = 394 (950), 275 (22 000). MS

(

HH 3 2 HH

(ESI ): m/z (%) 1347.49 (10) [M

64 76

−

(BF )] , i.e.,

[C H AgAuBF N ] , 1153.59 (53) [M − Ag − 2(BF )] , i.e.,

64 76

AuN ] , 630.25 (100) [M

−

2(BF )]

i.e.,

(

[C H AgAuN ] , with the corresponding isotopic pattern.

64 76 8

(

C_a_r_o_m), 143.4 (C_a_r_o_m), 139.6 (p-CH ), 135.2 (C_a_r_o_m), 134.5 (C_a_r_o_m),

30.2 (p-CH_D_i_P_P), 129.2 (m-CH_m_e_s), 129.1 (m-CH_m_e_s), 128.7 (C_a_r_o_m),

Synthesis of [CuAu(L) ](BF ) (18). To a solution of [CuBr-

pyr

4 2

(SMe )] (33.1 mg, 0.161 mmol) in acetonitrile (8 mL) was added,

27.0 (C_a_r_o_m), 125.7 (CH_i_m_i_d/m-CH_p_y_r), 125.6 (m-CH /CH_i_m_i_d),

under exclusion of light, a solution of AgBF (31.3 mg, 0.161 mmol)

pyr

24.7 (m-CH_D_i_P_P), 124.0 (CH_i_m_i_d), 123.7 (m-CH_p_y_r), 123.6 (m-

in the same solvent (8 mL), resulting in the formation a white

DOI: 10.1021/acs.organomet.9b00449

Organometallics XXXX, XXX, XXX−XXX

Organometallics

Article

precipitate. The suspension was stirred for 1 h at room temperature,

AUTHOR INFORMATION

Corresponding Authors

E-mail: thomas.simler@kit.edu.

E-mail: roesky@kit.edu.

■

ﬁltered, and added to a solution of [Au(L) ](BF ) (13) (200 mg,

0.161 mmol) in acetonitrile (10 mL). After stirring for an additional 2

h, the solution was ﬁltered over Celite and concentrated to ca. 1−2

mL. Addition of Et O precipitated 18 as a brown powder that was

isolated by ﬁltration and dried under vacuum. Crystals suitable for X-

ORCID

ray diﬀraction studies were obtained by slow diﬀusion of Et O in a

Thomas Simler: 0000-0002-0184-303X

Thomas J. Feuerstein: 0000-0002-9278-0678

Manfred M. Kappes: 0000-0002-1199-1730

Peter W. Roesky: 0000-0002-0915-3893

CH Cl solution of the complex. Yield of the crystals: 110 mg (0.079

mmol), 49%. Anal. Calcd for C H AuB CuF N (1391.49): C,

(

5.24; H, 5.51; N, 8.05. Found: C, 54.88; H, 5.25; N, 7.86. H NMR

400.30 MHz, CDCl ): δ [ppm]: 8.12 (d, J = 7.8 Hz, 2H, m-

3 HH

^C^Hpyr), 7.98 (t, J = 7.9 Hz, 2H, p-CH ), 7.81 (d, J = 1.8 Hz,

H, CH ), 7.36 (t, J = 7.8 Hz, 2H, p-CH ), 7.09 (dd, J

pyr

Notes

imid

DiPP

The authors declare no competing ﬁnancial interest.

.8 Hz, J = 1.0 Hz, 2H, m-CH ), 7.00 (d, J = 7.8 Hz, 2H, m-

DiPP

CH ), 6.94 (dd, J = 7.8 Hz, J = 1.0 Hz, 2H, m-CH_D_i_P_P), 6.90

pyr

ACKNOWLEDGMENTS

(

d, J = 1.8 Hz, 2H, CH_i_m_i_d), 6.87 (s, 2H, m-CH_m_e_s), 6.60 (s, 2H,

m-CH_m_e_s), 5.39 (d, J = 18.0 Hz, A part of an AB spin system, 2H,

CH ), 4.87 (d, J = 17.9 Hz, B part of an AB spin system, 2H,

CH ), 2.31 (s, 6H, CCH ), 2.29 (s, 12H, o-CH

6.1 Hz, 2H, CH(CH ) ), 2.01 (sept, J_H_H= 6.5 Hz, 2H,

CH(CH ) ), 1.03 (d, J = 6.7 Hz, 6H, CH(CH ) ), 1.01 (d, J =

.7 Hz, 6H, CH(CH ) ), 0.98 (s, 6H, p-CH

Hz, 6H, CH(CH ) ), 0.66 (d, J_H_H= 6.9 Hz, 6H, CH(CH ) ).

■

Financial support by the DFG-funded transregional collabo-

rative research center SFB/TRR 88 “Cooperative Eﬀects in

Homo and Heterometallic Complexes (3MET)”, projects C3

and C7, is gratefully acknowledged. T.S. thanks the Alexander

von Humboldt Foundation for a postdoctoral fellowship. We

thank Ms. Helga Berberich and Ms. Sibylle Schneider for help

with NMR and X-ray measurements, respectively. We are

grateful to Prof. Dieter Fenske for the collection of the X-ray

data of 14.

), 2.26 (sept, J

3 mes

≈

3 2

), 0.84 (d, J = 6.8

3 mes HH

3 2

C{ H} NMR (100.67 MHz, CDCl ): δ [ppm]: 185.8 (C_N_H_C), 168.8

(

C(N)CH ), 156.7 (C_a_r_o_m), 152.2 (C_a_r_o_m), 146.0 (C_a_r_o_m), 144.8

(

C_a_r_o_m), 143.4 (C_a_r_o_m), 139.2 (p-CH ), 135.2 (C_a_r_o_m), 133.9 (C_a_r_o_m),

pyr

30.4 (p-CH_D_i_P_P), 129.2 (m-CH_m_e_s), 129.1 (m-CH_m_e_s), 128.5 (C_a_r_o_m),

27.0 (C_a_r_o_m), 125.9 (CH_i_m_i_d), 125.4 (m-CH ), 124.6 (m-CH_D_i_P_P),

REFERENCES

pyr

■

24.4 (m-CH ), 123.8 (CHimid⁾^,¹²³^.⁷⁽^m^-^C^H ), 55.8 (CH ), 28.6

pyr

DiPP

(1) Braunstein, P.; Oro, L. A.; Raithby, P. R. Metal Clusters in

Chemistry; Weinheim: Wiley-VCH, 1999; Vol. I, p 459−560.

(2) (a) Buchwalter, P.; Rose, J.; Braunstein, P. Multimetallic

Catalysis Based on Heterometallic Complexes and Clusters. Chem.

Rev. 2015, 115, 28−126. (b) Pye, D. R.; Mankad, N. P. Bimetallic

Catalysis for C−C and C−X Coupling Reactions. Chem. Sci. 2017, 8,

1705−1718.

(

CH(CH ) ), 27.8 (CH(CH ) ), 24.8 (CH(CH ) ), 24.49 (CH-

CH ) ), 24.46 (CH(CH ) ), 23.9 (CH(CH ) ), 20.9 (o-CH3 mes⁾^,

3 2

9.0 (C(N)CH ), 16.9 (o-CH3 mes⁾^,¹⁶^.²⁽^p^-^C^H3 mes⁾^.^I^R⁽^A^T^R⁾^:^ν

−

(cm ) = 3160 (w), 3130 (m), 3102 (vw), 2966 (m), 2951 (sh), 2929

(vw), 2870 (w), 1614 (w), 1592 (s), 1562 (w), 1475 (sh), 1463 (m),

1424 (m), 1376 (vw), 1367 (sh), 1337 (w), 1308 (s), 1256 (s), 1235

(w), 1215 (m), 1199 (w), 1181 (vw), 1154 (w), 1126 (sh), 1094 (w),

(3) (a) Schmidbaur, H.; Schier, A. A Briefing on Aurophilicity.

Chem. Soc. Rev. 2008, 37, 1931−1951. (b) Yam, V. W.-W.; Cheng, E.

C.-C. Highlights on the Recent Advances in Gold Chemistrya

Photophysical Perspective. Chem. Soc. Rev. 2008, 37, 1806−1813.

059 (s), 1030 (m), 998 (m), 963 (w), 938 (vw), 850 (w), 800 (m),

86 (m), 757 (m), 733 (w), 707 (w), 637 (vw), 561 (w), 520 (w),

61 (vw). UV/vis (CH Cl ): λ [nm] (ε [L mol cm ]) = 560

max

−1

10 10

(

sh, 1500), 466 (3300), 334 (3600), 275 (19 000). MS (ESI ): m/z

%) 1303.52 (<1) [M − (BF )] , i.e., [C H AuCuBF N ] , 1153.59

Heterometallic Clusters of the Transition Metals. Chem. Soc. Rev.

2011, 40, 2741−2760. (d) Schmidbaur, H.; Schier, A. Argentophilic

Interactions. Angew. Chem., Int. Ed. 2015, 54, 746−784.

64 76

100) [M − Cu − 2(BF )] , i.e., [C H AuN ] , 608.26 (1) [M −

64 76

(BF )] , i.e., [C H AuCuN ] , with the corresponding isotopic

64 76

pattern.

(4) (a) Yam, V. W.-W.; Lo, K. K.-W. Luminescent Polynuclear d

Metal Complexes. Chem. Soc. Rev. 1999, 28, 323−334. (b) Yam, V.

W.-W.; Wong, K. M.-C. Luminescent Metal Complexes of d , d and

ASSOCIATED CONTENT

Supporting Information

The Supporting Information is available free of charge on the

ACS Publications website at DOI: 10.1021/acs.organo-

met.9b00449 .

■

Transition Metal Centres. Chem. Commun. 2011, 47, 11579−

11592.

5) (a) Ku

(

hnel, E.; Shishkov, I. V.; Rominger, F.; Oeser, T.;

Hofmann, P. Synthesis and Structures of Copper(I) Complexes with

Phosphino-Functionalized N-Heterocyclic Carbenes (NHCP) and

Bis-N-Heterocyclic Carbenes (Bis-NHC). Organometallics 2012, 31,

000−8011. (b) Ai, P.; Danopoulos, A. A.; Braunstein, P.; Monakhov,

Synthesis of compounds 1−3, speciﬁc comments for

crystal data, summary table of crystal data, crystal

structure representations of 8−18 with thermal

ellipsoids, NMR spectra of compounds 3, 4, and 6−

K. Y. A Novel, Rigid Diphosphine with an Active NHC Spacer; Di-

and Trinuclear Complexes of d Coinage Metals. Chem. Commun.

014, 50, 103−105. (c) Simler, T.; Braunstein, P.; Danopoulos, A. A.

Relative Lability and Chemoselective Transmetallation of NHC in

Hybrid Phosphine-NHC Ligands: Access to Heterometallic Com-

plexes. Angew. Chem., Int. Ed. 2015, 54, 13691−13695. (d) Bestgen,

S.; Gamer, M. T.; Lebedkin, S.; Kappes, M. M.; Roesky, P. W. Di- and

Trinuclear Gold Complexes of Diphenylphosphinoethyl-Functional-

ised Imidazolium Salts and their N-Heterocyclic Carbenes: Synthesis

and Photophysical Properties. Chem. - Eur. J. 2015, 21, 601−614.

8, IR spectra of compounds 8−18, UV−vis spectra of

complexes 15 −18, and photoluminescence decay of

complex 17 (PDF)

Accession Codes

CCDC 1935666 −1935675 contain the supplementary crys-

tallographic data for this paper. These data can be obtained

free of charge via www.ccdc.cam.ac.uk/data_request/cif , or by

emailing data_request@ccdc.cam.ac.uk , or by contacting The

Cambridge Crystallographic Data Centre, 12 Union Road,

Cambridge CB2 1EZ, UK; fax: +44 1223 336033.

(e) Simler, T.; Braunstein, P.; Danopoulos, A. A. Coinage Metal

Complexes with Bridging Hybrid Phosphine-NHC Ligands: Synthesis

of Di- and Tetra-Nuclear Complexes. Dalton Trans. 2016, 45, 5122−

139. (f) Ai, P.; Mauro, M.; De Cola, L.; Danopoulos, A. A.;

Braunstein, P. A Bis(Diphosphanyl N-Heterocyclic Carbene) Gold

Complex: A Synthon for Luminescent Rigid AuAg Arrays and Au

DOI: 10.1021/acs.organomet.9b00449

Organometallics XXXX, XXX, XXX−XXX

Organometallics

Article

and Cu Double Arrays. Angew. Chem., Int. Ed. 2016, 55, 3338−3341.

(16) Teng, Q.; Huynh, H. V. A Unified Ligand Electronic Parameter

Based on C NMR Spectroscopy of N-Heterocyclic Carbene

(

g) Ai, P.; Mauro, M.; Gourlaouen, C.; Carrara, S.; De Cola, L.;

Tobon, Y.; Giovanella, U.; Botta, C.; Danopoulos, A. A.; Braunstein,

P. Bonding, Luminescence, Metallophilicity in Linear Au and Au Ag

Complexes. Dalton Trans. 2017, 46, 614−627.

(17) Johnson, M. T.; van Rensburg, J. M. J.; Axelsson, M.; Ahlquist,

M. S. G.; Wendt, O. F. Reactivity of NHC Au(I)−C σ-Bonds with

Electrophiles. An Investigation of their Possible Involvement in

Catalytic C−C Bond Formation. Chem. Sci. 2011, 2, 2373−2377.

(18) Stollenz, M.; Meyer, F. Mesitylcopper − A Powerful Tool in

Synthetic Chemistry. Organometallics 2012, 31, 7708−7727.

(19) (a) Boehme, C.; Frenking, G. N-Heterocyclic Carbene,

Silylene, and Germylene Complexes of MCl (M = Cu, Ag, Au). A

Theoretical Study1. Organometallics 1998, 17, 5801−5809. (b) Nem-

csok, D.; Wichmann, K.; Frenking, G. The Significance of π

Interactions in Group 11 Complexes with N-Heterocyclic Carbenes.

Organometallics 2004, 23, 3640−3646.

Chains Stabilized by Rigid Diphosphanyl NHC Ligands. Inorg. Chem.

016, 55, 8527−8542.

6) (a) Kiefer, C.; Bestgen, S.; Gamer, M. T.; Lebedkin, S.; Kappes,

(

M. M.; Roesky, P. W. Alkynyl-Functionalized Gold NHC Complexes

and their Coinage Metal Clusters. Dalton Trans. 2015, 44, 13662−

13670. (b) Kiefer, C.; Bestgen, S.; Gamer, M. T.; Kuhn, M.; Lebedkin,

S.; Weigend, F.; Kappes, M. M.; Roesky, P. W. Coinage Metal

Complexes of Bis-Alkynyl-Functionalized N-Heterocyclic Carbenes:

Reactivity, Photophysical Properties, and Quantum Chemical

Investigations. Chem. - Eur. J. 2017, 23, 1591−1603.

(7) (a) Pearson, R. G. Hard and Soft Acids and Bases. J. Am. Chem.

Soc. 1963, 85, 3533−3539. (b) Pearson, R. G. The HSAB Principle 

(20) Visbal, R.; Gimeno, M. C. N-Heterocyclic Carbene Metal

Complexes: Photoluminescence and Applications. Chem. Soc. Rev.

2014, 43, 3551−3574.

More Quantitative Aspects. Inorg. Chim. Acta 1995, 240, 93−98.

(8) (a) Kaub, C.; Lebedkin, S.; Bestgen, S.; Koppe, R.; Kappes, M.

(21) Perry, M. C.; Cui, X.; Powell, M. T.; Hou, D.-R.; Reibenspies, J.

M.; Roesky, P. W. Defined Tetranuclear Coinage Metal Chains.

Chem. Commun. 2017, 53, 9578−9581. (b) Kaub, C.; Lebedkin, S.; Li,

A.; Kruppa, S. V.; Strebert, P. H.; Kappes, M. M.; Riehn, C.; Roesky,

H.; Burgess, K. Optically Active Iridium Imidazol-2-ylidene-oxazoline

Complexes: Preparation and Use in Asymmetric Hydrogenation of

Arylalkenes. J. Am. Chem. Soc. 2003, 125, 113−123.

P. W. Bimetallic d -Metal Complexes of a Bipyridine Substituted N-

(22) Uson, R.; Laguna, A.; Laguna, M.; Briggs, D. A.; Murray, H. H.;

Heterocyclic Carbene. Chem. - Eur. J. 2018, 24, 6094−6104.

Fackler, J. P. In Inorganic Syntheses; John Wiley & Sons, Inc., 1989;

Vol. 26, pp 85−91.

(

9) Wang, M.; Romelt, C.; Weyhermuller, T.; Wieghardt, K.

Coordination Modes, Oxidation, and Protonation Levels of 2,6-

Pyridinediimine and 2,2′:6′,2′-Terpyridine Ligands in New Com-

plexes of Cobalt, Zirconium, and Ruthenium. An Experimental and

(23) Lauterbach, T.; Livendahl, M.; Rosellon, A.; Espinet, P.;

Echavarren, A. M. Unlikeliness of Pd-Free Gold(I)-Catalyzed

Sonogashira Coupling Reactions. Org. Lett. 2010, 12, 3006−3009.

Density Functional Theory Computational Study. Inorg. Chem. 2019,

(24) (a) Tsuda, T.; Yazawa, T.; Watanabe, K.; Fujii, T.; Saegusa, T.

(

8, 121−132.

Preparation of Thermally Stable and Soluble Mesitylcopper(I) and its

10) (a) Parks, J. E.; Wagner, B. E.; Holm, R. H. Syntheses

Application in Organic Synthesis. J. Org. Chem. 1981, 46, 192−194.

Employing Pyridyllithium Reagents: New Routes to 2,6-Disubstituted

(

b) Eriksson, H.; Håkansson, M. Mesitylcopper: Tetrameric and

Pyridines and 6,6′-Disubstituted 2,2′-Bipyridyls. J. Organomet. Chem.

Pentameric. Organometallics 1997, 16, 4243−4244.

1973, 56, 53−66. (b) Bianchini, C.; Giambastiani, G.; Rios, I. G.;

(25) Bolm, C.; Ewald, M.; Felder, M.; Schlingloff, G. Enantiose-

Meli, A.; Oberhauser, W.; Sorace, L.; Toti, A. Synthesis of a New

Polydentate Ligand Obtained by Coupling 2,6-Bis(imino)pyridine

and (Imino)pyridine Moieties and Its Use in Ethylene Oligomeriza-

tion in Conjunction with Iron(II) and Cobalt(II) Bis-halides.

Organometallics 2007, 26, 5066−5078.

^l^e^c^tⁱ^v^e^S^yⁿ^t^h^e^sⁱ^s^o^f^O^p^tⁱ^c^a^l^l^y^A^c^tⁱ^v^e^P^y^rⁱ^dⁱⁿ^e^D^e^rⁱ^v^a^tⁱ^v^e^s^aⁿ^d^C2^-

Symmetric 2,2′-Bipyridines. Chem. Ber. 1992, 125, 1169−1190.

(26) Bur, D.; Corminboeuf, O.; Cren, S.; Fretz, H.; Grisostomi, C.;

Leroy, X.; Pothier, J.; Richard-Bildstein, S. Preparation of Amino-

pyrazole Derivatives as ALXR Receptor Agonists. Patent

WO2009077954, 2009.

(11) (a) Steiner, T. Hydrogen-Bond Distances to Halide Ions in

Organic and Organometallic Crystal Structures: Up-to-date Database

(27) de Mello, J. C.; Wittmann, H. F.; Friend, R. H. An Improved

Study. Acta Crystallogr., Sect. B: Struct. Sci. 1998, 54, 456−463.

Experimental Determination of External Photoluminescence Quan-

(b) Steiner, T.; Desiraju, G. R. Distinction Between the Weak

tum Efficiency. Adv. Mater. 1997, 9, 230−232.

Hydrogen Bond and the van der Waals Interaction. Chem. Commun.

998, 891−892. (c) Steiner, T. The Hydrogen Bond in the Solid

State. Angew. Chem., Int. Ed. 2002, 41, 48−76. (d) Kovacs, A.; Varga,

Z. Halogen Acceptors in Hydrogen Bonding. Coord. Chem. Rev. 2006,

50, 710−727.

12) (a) Wang, H. M. J.; Lin, I. J. B. Facile Synthesis of Silver(I)−

Carbene Complexes. Useful Carbene Transfer Agents. Organometallics

998, 17, 972−975. (b) Garrison, J. C.; Youngs, W. J. Ag(I) N-

(28) (a) Sheldrick, G. A Short History of SHELX. Acta Crystallogr.,

Sect. A: Found. Crystallogr. 2008, 64, 112−122. (b) Sheldrick, G.

Crystal Structure Refinement with SHELXL. Acta Crystallogr., Sect. C:

Struct. Chem. 2015, 71, 3−8.

(

(29) Dolomanov, O. V.; Bourhis, L. J.; Gildea, R. J.; Howard, J. A.

K.; Puschmann, H. OLEX2: a Complete Structure Solution,

Refinement and Analysis Program. J. Appl. Crystallogr. 2009, 42,

339−341.

Heterocyclic Carbene Complexes: Synthesis, Structure, and Applica-

tion. Chem. Rev. 2005, 105, 3978−4008. (c) Lin, I. J. B.; Vasam, C. S.

Preparation and Application of N-Heterocyclic Carbene Complexes

of Ag(I). Coord. Chem. Rev. 2007, 251, 642−670. (d) Lin, J. C. Y.;

Huang, R. T. W.; Lee, C. S.; Bhattacharyya, A.; Hwang, W. S.; Lin, I. J.

B. Coinage Metal−N-Heterocyclic Carbene Complexes. Chem. Rev.

(

009, 109, 3561−3598.

13) Groom, C. R.; Bruno, I. J.; Lightfoot, M. P.; Ward, S. C. The

Cambridge Structural Database. Acta Crystallogr., Sect. B: Struct. Sci.,

Cryst. Eng. Mater. 2016, 72, 171−179.

(14) (a) Baker, M. V.; Barnard, P. J.; Brayshaw, S. K.; Hickey, J. L.;

Skelton, B. W.; White, A. H. Synthetic, Structural and Spectroscopic

Studies of (Pseudo)halo(1,3-di-tert-butylimidazol-2-ylidine)gold

Complexes. Dalton Trans. 2005, 37−43. (b) Johnson, A.; Gimeno,

M. C. An Efficient and Sustainable Synthesis of NHC Gold

Complexes. Chem. Commun. 2016, 52, 9664−9667.

(

15) de Fremont, P.; Scott, N. M.; Stevens, E. D.; Nolan, S. P.

Synthesis and Structural Characterization of N-Heterocyclic Carbene

Gold(I) Complexes. Organometallics 2005, 24, 2411−2418.

DOI: 10.1021/acs.organomet.9b00449

Organometallics XXXX, XXX, XXX−XXX

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DOI: 10.1021/acs.organomet.9b00449

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