Synthesis and characterization of 1′-(diphenylphosphino)-1-isocyanoferrocene, an organometallic ligand combining two different soft donor moieties, and its Group 11 metal complexes

View Article Online

View Journal

Dalton

Transactions

Accepted Manuscript

This article can be cited before page numbers have been issued, to do this please use: K. Skoch, I.

Cisarova, J. Schulz, U. Siemeling and P. Stepnicka, Dalton Trans., 2017, DOI: 10.1039/C7DT02336G.

This is an Accepted Manuscript, which has been through the

Volume 45 Number

1 7 January 2016 Pages 1–398

Royal Society of Chemistry peer review process and has been

accepted for publication.

Dalton

Transactions

Accepted Manuscripts are published online shortly after

An international journal of inorganic chemistry

www.rsc.org/dalton

acceptance, before technical editing, formatting and proof reading.

Using this free service, authors can make their results available

to the community, in citable form, before we publish the edited

article. We will replace this Accepted Manuscript with the edited

and formatted Advance Article as soon as it is available.

You can find more information about Accepted Manuscripts in the

author guidelines .

Please note that technical editing may introduce minor changes

to the text and/or graphics, which may alter content. The journal’s

standard T erms & Conditions and the ethical guidelines, outlined

in our author and reviewer resource centre, still apply. In no

event shall the Royal Society of Chemistry be held responsible

for any errors or omissions in this Accepted Manuscript or any

consequences arising from the use of any information it contains.

ISSN 1477-9226

PAPER

Joseph T. Hupp, Omar K. Farha et al.

Eﬃcient extraction of sulfate from water using

framework

a Zr-metal–organic

rsc.li/dalton

Please do not adjust margins

Dalton Transactions

Page 1 of 16

View Article Online

DOI: 10.1039/C7DT02336G

Journal Name

ARTICLE

Synthesis and characterization of 1′-(diphenylphosphino)-1-

isocyanoferrocene, an organometallic ligand combining two

different soft donor moieties, and its Group 11 metal complexes

Received 00th January 20xx,

Accepted 00th January 20xx

Karel Škoch,^aIvana Císařová,^aJiří Schulz,^aUlrich Siemeling,^band Petr Štěpnička^a*

DOI: 10.1039/x0xx00000x

www.rsc.org/

The development of a practical synthesis of 1´-(diphenylphosphino)-1-aminoferrocene (2) and its P-borane adduct (2B)

allowed the facile preparation of 1’-(diphenylphosphino)-1-isocyanoferrocene (1). This compound combining two specific

soft-donor moieties was studied as a ligand for univalent Group 11 metal ions. The reactions of 1 with AgCl at 1:1 and 2:1

molar ratios only led to the coordination polymer [Ag₂(μ-Cl)₂(μ(P,C)-1)]_n(6), while those with Ag[SbF₆] provided the dimer

[Ag(Me₂CO-κO)(μ(P,C)-1)]₂[SbF₆]₂and the quadruply-bridged disilver complex [Ag₂(μ(P,C)-1)₄][SbF₆]₂(8), respectively.

Addition of 1 to [AuCl(tht)] (tht = tetrahydrothiophene) afforded the mono- and the digold complex, [AuCl(1-κP)] (9) and

[(μ(P,C)-1)(AuCl)₂] (10), depending on the reaction stoichiometry. Finally, the reaction of 1 with [Au(tht)₂][SbF₆] or

halogenide removal from 9 with AgNTf₂led to cationic dimers [Au₂(μ(P,C)-1)₂]X₂(11, X = SbF₆(a) or NTf₂(b)). Catalytic tests

in the Au-mediated isomerization of (Z)-3-methylpent-2-en-4-yn-1-ol to 2,3-dimethylfuran revealed that 11a and 11b are

substantially less catalytically active than their analogues containing 1´-(diphenylphosphino)-1-cyanoferrocene as the

ligand, most likely due to a stronger coordination of the isonitrile moiety, which prevents dissociation of the dimeric

complexes into catalytically active monomeric species.

soft-soft hybrid donor toward Group 11 metals.¹²The often

unusual structures of the isolated complexes as well as

Introduction

excellent catalytic properties of the Au(I)-

us to expand our studies toward the closest isomeric

compound, 1’-(diphenylphosphino)-1-isocyanoferrocene ( in

Scheme 1), which formally falls between diisocyanide and

D

complexes^12bled

Isocyanides are useful synthetic intermediates¹as well as

attractive σ-donor/π-acceptor ligands for coordination

chemistry.²Even though the ferrocene motif has been

frequently used in ligand design,³ferrocene-based isocyanides

1

B

the widely studied 1,1’-bis(diphenylphosphino)ferrocene

(dppf).¹³

were long overlooked. For instance, isocyanoferrocene (A,

Scheme 1) was first reported in 1987^4,5(i.e., relatively late for a

simple ferrocene derivative⁶) and later studied as a redox-

active metalloligand in transition metal complexes.^4,7More

recent studies focused on its doubly functionalized congener,

NC

Me

NC

Fe

1,1’-diisocyanoferrocene

(

B

),⁸

disclosed

unexpected

coordination and reactivity of this compound in multinuclear

complexes and formation of self-assembled monolayers on

gold surfaces.⁹Presumably the latest entry into the still narrow

class of ferrocene-based isonitriles¹⁰is the planar-chiral

A

B

C

PPh₂

CN

PPh₂

NC

PPh₂

NC

Fe

derivative, (S_p)-2-methyl-1-isocyanoferrocene (

Recently we reported the synthesis of 1’-(diphenylphosphino)-

1-cyanoferrocene ( ) and the coordination properties of this

C

).¹¹

D

E

1

D

Scheme 1.

Although the transposition of the nitrogen and carbon atoms

in the structures of and might appear marginal in terms of

D

1

chemical constitution, it can be expected to dramatically alter

the reactivity and coordination properties of these

compounds. It is also noteworthy that similar ligands

combining isocyanide and phosphine donor moieties remain

limited to only a handful of compounds including Ph₂P(CH₂)_nNC

This journal is © The Royal Society of Chemistry 20xx

J. Name., 2013, 00, 1-3 | 1

Please do not adjust margins

Dalton Transactions

Page 2 of 16

View Article Online

DOI: 10.1039/C7DT02336G

ARTICLE

Journal Name

(n = 2,¹⁴3¹⁵) and the recently reported compound

1).¹⁶

E

(Scheme In the last step, which was the dehydration of formamide 5 to

, the standard reagents (POCl₃/NEt₃, COCl₂/iPr₂NH)²⁴

isonitrile

1

This contribution describes the preparation and structural failed, typically resulting in extensive darkening of the reaction

characterization of the new phosphino-isonitrile ligand and mixture and oxidation of the phosphine moiety (confirmed by

its complexes with Ag(I) and Au(I) ions. Also reported are the ³¹P NMR analysis). This led us to utilize the method previously

results of preliminary catalytic tests with Au(I)-

complexes used to convert oxime Ph₂PfcCH=NOH into nitrile D ²⁵

counterparts. Gratifyingly, addition of Castro’s reagent (i.e., (benzotriazol-1-

yloxy)tris(dimethylamino)phosphonium hexafluorophosphate,

BOP) and 1,8-diazabicyclo(5.4.0)undec-7-ene (DBU) to amide

ensued in a clean formation of isonitrile , which was isolated

in a 71% yield following chromatographic purification.

1

.

aimed at a comparison with their Au(I)-

D

5

Results and Discussion

1

Synthesis of phosphino-isonitrile 1

In analogy to the syntheses of organic isocyanides,¹⁷we

anticipated that our target compound can be obtained from

the known 1’-(diphenylphosphino)-1-aminoferrocene ( ) by

1. LiBu

2. ClPPh₂

3. BH₃SMe₂

Br

PPh₂

Br

1

S₈

BH₃SMe₂

Fe

2

Br

formylation and subsequent dehydration (Scheme 2). Although

this assumption later proved correct, this straightforward plan

3

BH₃

S

had to be modified because the synthesis of amine

2

from 1’-

described in the

literature¹⁹was found to be irreproducible in our hands.^20,21

PPh₂

18

(diphenylphosphino)-1-bromoferrocene (3)

Fe

Br

3S

3B

1. LiBu

2. TsN₃

1. LiBu

2. TsN₃

S

BH₃

PPh₂

Scheme 2. Intended preparation of 1 from amine 2.

Fe

Considering the generally low stability of aminoferrocene

derivatives, the often harsh reaction conditions required to

obtain them,²²an also the sensitivity of phosphine groups to

N₃

4S

4B

1. Li[AlH₄]

2. HCOOAc

Li[AlH₄]

oxidation, the synthetic routes toward

1 were redesigned to

include phosphine-protected intermediates that allow the

introduction of the azide moiety (without an unwanted

Staudinger reaction) and its subsequent reduction to amine

group (Scheme 3).

BH₃

PPh₂

1. Raney Ni

2. HCOOAc

Fe

NHCHO

NH₂

Because some of us have successfully employed the protection

of a phosphine group by thionation during the synthesis of

5B

2B

Ph₂PfcNHCH₂t-Bu^21a(fc

=

ferrocene-1,1’-diyl),

approach was adopted also for the synthesis of

left branch) with the prospect that removal of the P-bound

sulfur atom and reduction of the azide group (−N₃−NH₂)

can be effected in a single step by reacting intermediate 4S

with Raney nickel. The starting phosphine bromide was

a

similar

dabco

1

(Scheme 3,

PPh₂

NH₂

→

HCOOAc

Fe

3

NHCHO

smoothly thionated with elemental sulfur and the stable P-

sulfide 3S was lithiated and treated with 4-toluenesulfonyl

azide (TsN₃) to afford azide 4S in a good yield. A small amount

of TsN₃present in the reaction product did not interfere during

the following step, after which it could be easily removed. The

subsequent reaction of 4S with Raney nickel and then with

5

2

PPh₂

NC

BOP/DBU

Fe

1

acetic formic anhydride provided the desired formamide

5 as a

Scheme 3. Alternative syntheses of

intermediates. Legend: TsN₃= 4-toluenesulfonyl azide, BOP = (benzotriazol-1-

yloxy)tris(dimethylamino)phosphonium hexafluorophosphate, dabco 1,4-

diazabicyclo[2.2.2]octane, DBU = 1,8-diazabicyclo(5.4.0)undec-7-ene.

1 exploiting different P-protected

ca. 4:5 mixture of (E) and (Z) isomers (N.B. the acylation was

=

performed directly to prevent a possible decomposition of

intermediate amine

2). However, the transformation of 4S into

Although the synthesis of

1 was successful, we sought for a

5

typically suffered from low yields (below 30%) and the

more efficient synthetic procedure, utilizing borane as the

protecting group (Scheme 3, right branch). The necessary

starting material 3B was prepared by the reaction of

product was contaminated by the dephosphorylated amide,

FcNHCHO (Fc = ferrocenyl).²³

2 | J. Name., 2012, 00, 1-3

This journal is © The Royal Society of Chemistry 20xx

Please do not adjust margins

Dalton Transactions

Page 3 of 16

View Article Online

DOI: 10.1039/C7DT02336G

Journal Name

ARTICLE

phosphine-bromide

3 with BH₃·SMe₂or, alternatively, via a overlap of the independent molecules, see the ESI, Figure S4).

practical one-pot procedure (lithiation, phosphinylation, Otherwise, the parameters describing the molecular geometry

borylation) from 1,1’-dibromoferrocene.¹⁸Lithiation of 3B of the azides are similar to the respective data reported for

32

followed by quenching with TsN₃afforded azide 4B in a 89% FcN₃,²⁸fc(N₃)₃,²⁹FcP(S)Ph₂,³⁰dppfS₂,³¹and dppf·2BH₃(Fc =

yield. Compound 4B was found to be stable when stored at ferrocenyl).

low temperatures in the dark but gradually decomposed upon

exposure to direct day light. The subsequent reduction with

Li[AlH₄] in THF smoothly converted azide 4B into the protected

amine 2B. This compound was in turn formylated to give 5B or

isolated and converted the free phosphinoamine

Deprotection of 5B with 1,4-diazabicyclo[2.2.2]octane (dabco)

or, alternatively, acylation of with HCOOAc afforded

, which was in turn used to prepare the target

as outlined above (see Scheme 3).

2.

2

formamide

isocyanide

5

1

Although longer by one step, the synthesis of

protected intermediates proved to be much more efficient in

terms of the overall yield (compare the 70% yield of from

bromide with ca. 25% yield for the conversion via the

P=S intermediates) and selectivity. Besides, it provided a

reliable access to amine and its P-protected form 2B that are

1 via borane-

1

3

3 → 1

Figure 1. Molecular structures of 4S (molecule 1) and 4B.

2

both attractive for further syntheses. Compound 2B appears to

be particularly stable in both the solid state and solution. For

instance, the adduct did not undergo any detectable

decomposition or BH₃migration between the Lewis basic

amine and phosphine groups when its solutions in CDCl₃,

CD₃CN and C₆D₆were stored at room temperature for 2 days.

Table 1. Selected distances and angles for 4S and 4B (in Å and deg).^a

4S (Y = S)

Parametr

4B (Y = B)

mol 1

1.652(1)

1.646(1)

1.4(1)

mol 2

Fe-Cg1

Fe-Cg2

∠Cp1,Cp2

τ

1.649(2)

1.632 (1)

1.3(2)

1.654(1)

1.6464(9)

2.6(1)

Accordingly, the reaction of

CDCl₃) produced adduct 2B as the sole product (N.B. adduct

·2BH₃was detected only when larger amounts of the borane

source were employed).

Isocyanide and all intermediates occurring en route to this

2 with 1 equiv. of BH₃·SMe₂(in

−122.8(2)

1.790(2)

1.9567(8)

1.415(4)

1.235(4)

1.130(4)

115.6(2)

173.3(3)

154.9(2)

1.790(3)

1.950(1)

1.417(5)

1.251(4)

1.143(5)

114.9(3)

171.3(4)

108.1(2)

1.790(2)

1.926(2)

1.422(3)

1.262(3)

1.123(4)

115.4(2)

172.1(3)

P-Cn6

2

P-Y

Cn1-N^α

N^α-N^β

1

N^β-N^γ

Cn1-N^α-N^β

N^α-N^β-N^γ

compound were characterized by multinuclear NMR and IR

spectroscopy, mass spectrometry and elemental analysis or HR

MS measurements. In addition, the solid state structures of

1,

2

,

4S 4B, and were determined by single-crystal X-ray

,

5

a

Definitions: Cp1 and Cp2 are the nitrogen- and phosphorus-substituted

cyclopentadienyl rings, respectively. Cg1 and Cg2 denote their centroids. τ =

torsion angle C1-Cg1-Cg2-C6. 4S: n = void/5 for molecules 1/2, 4B: n = void.

diffraction analysis. The ¹H and ¹³C NMR spectra confirmed the

presence of an unsymmetrically 1,1′-disubstituted ferrocene

moiety and the attached phosphorus groups in all cases. The

manipulations at the phosphorus substituent were manifested

The structures of

structural data are given in Table 2. The ferrocene unit in the

structure of has a synclinal eclipsed conformation (compare

the τ angle in Table 2 with the ideal value of 72°)^13aand is

negligibly tilted. Its phosphine substituent is oriented so that

one phenyl group points above the ferrocene scaffold while

the other as well as the lone pair of electrons are directed to

1 and 2 are displayed in Figure 2. Relevant

in the ³¹P NMR spectra, showing broad signals at δ_P

≈ 16 for

the BH₃adducts, and sharp singlets at δ_P−17 and 42 for the

1

≈

free phosphines and phosphine sulfides, respectively. In

addition to characteristic B−H stretching bands of the borane

adducts at 2340-2400 cm⁻¹,²⁶the IR spectra showed distinct

features due to the polar substituents, namely intense azide

ν(N₃) bands (4S: 2109 cm⁻¹, 4B: 2108 cm⁻¹) and amide ν(C=O)

the sides. The length of the N≡C bond of 1.157(3) is identical to

that in FcNC (1.157(5) Å)³³and the C1-N

(177.3(2)°).

≡C11 moiety is linear

vibrations (

ν(N C) vibration of

PhNC).²⁷

5

and 5B: 1663 cm⁻¹). The band attributable to the

was seen at 2126 cm⁻¹(cf. 2125 cm⁻¹for

≡

1

The arrangement of the phosphinoferrocene moiety in the

structure of amine is the same as in , including the

orientation of the cyclopentadienyl rings, and the C1-N bond in

has the same length as that in aminoferrocene (1.405(5) Å).³⁴

Notably, the crystal structure of amine lacks classical N−H··N

hydrogen bonds. However, one of the amine hydrogen atoms

(H1N) appears to be involved in an intramolecular N ⋅⋅⋅π

2

1

The crystal structures of 1 and intermediates 4S, 4B, 2 and 5

2

The molecular structures of azides 4S and 4B are presented in

Figure 1 and selected geometric parameters are given in Table

1. Compound 4S crystallizes with two structurally independent

molecules, which differ in the conformation of their ferrocene

units (see the τ angles in Table 1) and in the orientation of the

phenyl rings with respected to the ferrocene moiety (for an

2

−

H

interaction, being directed towards the phenyl ring C(18-23)

with an H···Cg distance (Cg is the ring centroid) of 2.93 Å.

This journal is © The Royal Society of Chemistry 20xx

J. Name., 2013, 00, 1-3 | 3

Please do not adjust margins

Dalton Transactions

Page 4 of 16

View Article Online

DOI: 10.1039/C7DT02336G

ARTICLE

Journal Name

Figure 3. Section of the hydrogen-bonded chain in the structure of 5 as viewed along

the crystallographic a axis. For clarity, the CH_nhydrogen atoms are omitted.

Complexes of 1 with Group 11 metals

With reference to our studies focused on the coordination

behavior of phosphinonitrile donor

to investigate the coordination properties of the isomeric

ligand towards univalent Group 11 metal ions.

Unfortunately, reactions of with CuCl and [Cu(MeCN)₄]X (X =

D

(Scheme 1),¹²we set out

1

BF₄and PF₆) as the common Cu(I) sources repeatedly failed to

provide any defined products, typically giving rise to

intractable precipitates (presumably of polymeric nature).

A defined, though also practically insoluble, product (N.B the

compound did not dissolve even in MeCN or DMSO) resulted

Figure 2. Molecular structures of 1 and 2.

Table 2. Selected distances and angles for 1, 2 and 5 (in Å and deg).^a

upon reacting ligand

AgCl (Scheme 4). X-ray diffraction analysis on crystalline

obtained by reaction of AgCl with 2 equiv. of in chloroform

and crystallization by addition of hexane revealed that the

structure of is built up from diamond-shaped {Ag₂(μ-Cl)₂}

fragments that are interconnected by four P,C-bridging ligands

into an infinite one-dimensional chain (Figure 4). Although

1 (1 or 2 equiv.) with freshly prepared

6

Parametr

Fe-Cg1

Fe-Cg2

∠Cp1,Cp2

τ

1^b

2

5^c

1

1.6438(8)

1.6431(8)

1.4(1)

1.6585(7)

1.6467(7)

1.09(9)

1.6482(7)

1.6408(6)

2.79(9)

6

−70.0(1)

1.814(2)

1.391(2)

69.0(1)

−86.3(1)

1.813 (1)

1.407(2)

1

P-C6

1.810(1)

1.410(2)

central Ag₂Cl₂motifs were found in the structures of, e.g.,

35

[(Ph₃P)₂Ag(µ-Cl)]₂and [(dppf-κ²P,P’)Ag(µ-Cl)]₂,³⁶the only

C1-N

a

related compound featuring two different donors whose

Definitions: Cp1 and Cp2 are the cyclopentadienyl rings C(1-5) and C(6-10),

respectively. Cg1 and Cg2 denote their centroids. τ = torsion angle C1-Cg1-Cg2-

C6. ^bFurther data: C11-N = 1.157(3), C1-N-C11 = 177.3(2). ^cFurther data: N-C24 =

1.338(2), C1-N-C24 = 126.5(1), C24-O = 1.227(2), N-C24-O = 125.1(2).

structure has been reported to date is the dinuclear complex

[(Ph₃P)(MeNC)Ag(µ-Br)]₂.³⁷Indeed, the structures of

6

and the

latter compound are similar except that in

6 the two donor

moieties are tethered by the ferrocene unit, which in turn

results in the formation of a polymeric assembly. It is also

Recrystallization of formamide

furnished crystals of the major (Z) isomer, which were used for

the structure determination. In the crystal, compound forms

infinite chains via N-H1N⋅⋅⋅ hydrogen bridges (N···O

2.808(2) Å) between molecules distributed around

crystallographic glide planes (Figure 3 and Table 2). The

individual molecules show a minor tilting at their ferrocene

units (ca. 3°) and an intermediate conformation between

synclinal eclipsed and anticlinal staggered. The amide moiety is

coplanar with its parent cyclopentadienyl ring (dihedral angle:

0.8(2)°), which suggests conjugation of these molecular parts.

5 from chloroform/hexane

noteworthy that ligand

D comprising the relatively harder

5

cyano group reacted with AgCl to give heterocubane [Ag(µ₃-

O

=

Cl)(

D

-κP)]₄(Ag:

D

= 1:1) or the dimers [Ag(

= 1:2).^12c

D

-κP)₂(µ-Cl)]₂and

[AgCl(

D

-κP)(µ(P,N)-

D

)]₂(Ag:

D

Ph₂

P

Fe

NC

PPh₂

NC

Ag

AgCl

Cl

Ag

Fe

NC

Fe

P

Ph₂

1

n

6

Scheme 4. Reaction of 1 with AgCl leading to coordination polymer 6.

The structure of

6 is presented in Figure 4 along with selected

distances and angles. Although the silver atoms appear

disordered over two positions differently positioned between

the phosphine and isonitrile donors (refined ratios: ≈97:3), the

overall structure is rather symmetrical. The central Ag₂Cl₂units

are practically regular squares and lie on crystallographic

inversion centers. Each silver(I) ion is further coordinated by

two phosphino-isonitrile ligands 1, once via the phosphorus

atom and once through the isonitrile moiety. Both Ag-P and

Ag-C bonds are shorter than the sum of the respective

covalent radii (Σr_cov(Ag,P) = 2.52 Å, Σ

r_cov(Ag,Csp) = 2.14 Å)³⁸

and the observed Ag-C distance (2.164(3) Å) is close to the

average Ag-C distances in Ag-isonitrile complexes (2.14(8) Å³⁹).

4 | J. Name., 2012, 00, 1-3

This journal is © The Royal Society of Chemistry 20xx

Please do not adjust margins

Dalton Transactions

Page 5 of 16

Journal Name

View Article Online

DOI: 10.1039/C7DT02336G

ARTICLE

The coordination environment of the silver ions is distorted

tetrahedral. Among the interligand angles, the Cl-Ag1-Cl’ angle

is the most acute (90°) and the C11’’-Ag1-Cl (120°) and P-Ag1-

C11’’ (118°) angles are the most opened.

[SbF₆]₂

Ph₂

P

OCMe₂

Ag[SbF₆]

(1 equiv.)

Ag

CN

Fe

The ferrocene moiety in the structure of

6 is roughly

NC

Ag

P

perpendicular to the Ag₂Cl₂ring (cf. the dihedral angle of the

C(1-5) ring and the Ag₂Cl₂plane of 82.6(1)°) and has an

intermediate conformation with τ of −52.5(2)°. Notably, the

Me₂CO

Ph₂

PPh₂

NC

7

Fe

length of the coordinated

C≡N bond (1.163(4) Å) is

indistinguishable within experimental error from that in free

1.

1

Ph₂

P

[SbF₆]₂

Ag

CN

P

Fe

Ag[SbF₆]

Fe

NC

(0.5 equiv.)

2

Ph₂

8

Scheme 5. Synthesis of Ag(I)-1 complexes from Ag[SbF₆].

Compounds

ray diffraction analysis. The complex cations in the crystal

structure of (Figure 5) lie around crystallographic inversion

7 and 8 have been structurally authenticated by X-

7

Figure 4. A section of the infinite polymeric array in the structure of 6. For clarity, all H

atoms and the less populated position of the disordered silver(I) ion were omitted.

Coordination geometry parameters (in Å and deg): Ag1-P 2.4529(7), Ag1-C11 2.164(3),

Ag1-Cl 2.6428(7), Ag1-Cl’ 2.6358(8), P-Ag1-C11 117.71(7), P-Ag1-Cl 111.46(2), P-Ag1-Cl’

103.46(2), C11’’-Ag1-Cl 110.35(7), C11’’-Ag1-Cl’ 120.30(8), Ag1-Cl-Ag1’ 89.76(2), Cl-Ag1-

Cl’ 90.24(2).

centers, which makes only their halves structurally

independent. Their tricoordinate silver ions exhibit an almost

linear arrangement of the ligating P and C atoms, with a minor

distortion due to the coordinated acetone (P-Ag-C ≈

Ag-P and Ag-C bonds in are shorter than those in

166°). The

(by 0.07

7

6

and 0.05 Å), suggesting stronger dative bonds in the former

cationic complex. In contrast, the Ag-O distance is substantially

Addition of ligand

coordinating anion in acetone led to the dimeric complex

[Ag₂{μ(P,C)- }₂(Me₂CO- O)₂][SbF₆]₂in Scheme 5). This

compound is structurally similar to [Ag₂{μ(P,N)- }₂(AcOEt-

O)₂][SbF₆]₂obtained from Ag[SbF₆] and ligand

^12cUnlike the

latter compound, however, complex appears to be stable in

1 (1 equiv.) to Ag[SbF₆] containing a weakly

elongated (compare Ag-O1S

≈ 2.63 Å with Σr_cov(Ag,O) = 2.11

1

κ

(7

Å), presumably due to a relatively weaker coordination and

steric reasons.

D

κ

D.

The cyclopentadienyl rings in

7 are tilted by 2.4(2)° and adopt

7

solution, which was manifested by a sharp ³¹P NMR signal at δ_P

6.8 split into a pair of concentric doublets by interactions with

¹⁰⁹Ag and ¹⁰⁷Ag (¹J_Ag,P= 709 and 615 Hz). Coordination of the

a conformation near to synclinal eclipsed (τ = 83.8(1)°), which

brings the phosphine moiety to the side of the fc-NC moiety

(cf. the angle subtended by the P-C6 and C1-N bonds of

79.7(2)°). Consequently, the P-Ag bond points to the same

isonitrile moiety was indicated by a shift of the ν(N

≡

C) band in

the IR spectrum to 2210 cm⁻(by 84 cm⁻¹to higher energies

with respect to ). The IR spectrum further confirmed the

presence of coordinated acetone through a sharp band of the

1

direction as the N

≡

formation of dimeric units Ag₂(µ(P,C)-

C moiety, which in turn allows the

consisting of two

1)

2

1

equivalent parts arranged in a side-by-side manner that

laterally coordinate the acetone molecules.

1

ν(C=O) vibration at 1695 cm⁻, which is 20 cm⁻less than for

neat acetone due to coordination.⁴⁰

Upon increasing the amount of the phosphino-isonitrile ligand

to 2 molar equiv., Ag[SbF₆] was smoothly converted to the

quadruply-bridged disilver(I) complex [Ag₂{μ(P,C)-

), which resembles an analogous Cu(I) complex obtained

from ligand , [Cu₂{μ(P,N)-

}₄][SbF₆]₂.^12aIn its ³¹P NMR

spectrum, complex gave rise to a broad doublet at δ_P–1.2

(¹J_Ag,P= 207 Hz).⁴¹The IR band due to coordinated isonitrile

1}₄][SbF₆]₂

(

8

D

8

1

groups was observed at 2167 cm⁻, i.e. shifted by ca. 40 cm⁻

to higher energies compared to uncoordinated ligand 1.

This journal is © The Royal Society of Chemistry 20xx

J. Name., 2013, 00, 1-3 | 5

Please do not adjust margins

Dalton Transactions

Page 6 of 16

View Article Online

DOI: 10.1039/C7DT02336G

ARTICLE

Journal Name

Figure 5. View of the complex cation in the structure of 7. The hydrogen atoms were

omitted for clarity. Coordination geometry parameters (in Å and deg): Ag-P 2.385(1),

Ag-C11’ 2.110(4), Ag-O1S 2.630(4), P-Ag-C11’ 165.5(1), P-Ag-O1S 91.29(9), C11’-Ag-O1S

102.0(2).

that a small fraction of the gold centers in the structure of

9 is

displaced towards the isonitrile group of an adjacent molecule

(vide infra). This phenomenon appears to be limited to the

solid state as an NMR study ruled out the formation of

isomeric monogold complexes (with P- and NC-bound ligand)

The structure determination on

8·3Me₂CO revealed a compact

and other species (e.g.,

1

and 10 formed by redistribution).

and symmetrical complex molecule located around

a

crystallographic two-fold axis (space group C2/c; the silver

atoms reside on this axis). Each silver(I) ion has a distorted

tetrahedral P₂C₂donor set being coordinated by four P,C-

Ph₂

P

PPh₂

NC

[AuCl(tht)]

(2 quiv.)

Au

Cl

Fe

– tht

bridging ligands

1. The lengths of the two structurally

NC Au Cl

independent Ag-P bonds differ by ca. 0.036 Å. A more

significant asymmetry observed for the Ag-CN bonds (0.059 Å)

1

10

for 11a

[Au(tht)₂][SbF₆]

is not relayed further as the C≡N bonds are similar in length

and the Ag-C N and Cp-N C moieties remain linear. Despite

[AuCl(tht)]

(1 equiv.), – tht

≡

the very different steric demands of the donor moieties, the

interligand angles around the silver(I) ions do not depart much

from the tetrahedral value, spanning a relatively narrow range

of 103.35(9)-115.88(3)°.

X₂

Ph₂

P

Ph₂

Au

11b

for

AgNTf₂

P

CN

Au

Cl

Fe

– AgCl

NC

Au

NC

P

Ph₂

9

11a

11b

(X = NTf₂)

(X = SbF₆),

11

Scheme 6. Preparation of Au(I)-

1

complexes

9

-

.

The structures of

selected geometric data. As stated above, the gold(I) ions in

the structure of are disordered over two positions (refined

occupancies: Au1 0.98, Au2 0.02; the ligand is considered

9 and 10 are shown in Figure 7 along with

9

≈

invariant). In the dominant position, the gold(I) ion has the

usual linear coordination whilst in the other it is approximately

trigonal with the isonitrile moiety located at a bonding

distance (Au2-C11

ferrocene unit in

≈

has a synclinal eclipsed conformation (τ =

2.09 Å,

Σr_cov(Au,Csp) = 2.05 Å). The

9

70.3(2)°) which, together with the spatial orientation of the

phenyl rings, allows for a compact arrangement of the linear

assembly interlinked via the incidental P-Au2-NC interactions.

Figure 6. View of the complex cation in the structure of 8·3Me₂CO. The hydrogen

atoms were omitted for clarity. Coordination geometry parameters (in Å and deg): Ag1-

P1 2.5376(9), Ag1-C61 2.264(3), Ag2-P2 2.5017(7), Ag2-C11 2.205(4), P1-Ag1-P1’

115.88(3), P1-Ag1-C61 103.35(9), P1-Ag1-C61’ 112.44(9), C61-Ag1-C61’ 109.5(1), P2-

Ag2-P2’ 109.65(2), P2-Ag2-C11 106.1(1), P2-Ag2-C11’ 112.61(7), C11-Ag2-C11’ 110.0(1);

Ag2-C11-N1 177.9(3), N1-C11 1.150(5), C1-N1-C11 179.0(3), Ag1-C61-N2 178.5(3), N2-

C61 1.148(3), C51-N2-C61 176.9(3). The prime-labeled atoms are generated by

crystallographic two-fold axis.

a

The reactions of

paralleled the chemistry noted in the Au(I)-

partly (Scheme 6). Depending on the ligand-to-metal ratio, the

reaction of with [AuCl(tht)] afforded either the phosphine

complex [AuCl( P)] ( ) or the trinuclear Au₂Fe complex 10

1

with [AuCl(tht)] (tht = tetrahydrothiophene)

D

system only

1

-κ

9

.

Both these products are poorly soluble (especially when

crystallized), which makes their full characterization by

solution techniques (e.g., NMR) impossible. Nevertheless, the

coordination of the phosphine moiety in

9

could be inferred

_P29.0). The

from a shift of the ³¹P NMR signal to a lower field (

δ

IR spectrum recorded with a solid sample (Nujol mull)

displayed two bands attributable to the free (2126 cm⁻¹) and

coordinated (2220 cm⁻¹, weak band; cf. ν_N2223 cm⁻¹for 10

)

≡

C

Figure 7. Simplified views of the crystal structures of 9 (top) and 10 (bottom). Selected

data for 9 (in Å and deg): Au1-P 2.2298(7), Au1-Cl 2.2896(8), Au2-P 2.533(6), Au2-Cl

2.652(6), Au2-C11’ 2.094(7), P-Au1-Cl 176.12(3), P-Au2-Cl 121.2(2), Au2'-N-C11

isonitrile moieties. Although unexpected, this observation is in

line with the result of the structure determination revealing

6 | J. Name., 2012, 00, 1-3

This journal is © The Royal Society of Chemistry 20xx

Please do not adjust margins

Dalton Transactions

Page 7 of 16

Journal Name

View Article Online

DOI: 10.1039/C7DT02336G

ARTICLE

155.1(4), N-C11 1.153(4), C1-N-C11 178.9(3). Selected data for 10 (in Å and deg): Au1-P

2.230(1), Au1-Cl1 2.288(1), P-Au1-Cl1 173.93(4), Au2-C11 1.930(5), Au2-Cl2 2.260(1),

C11-Au2-Cl2 176.9(1), Au2-C11-N 178.2(4).

The electrochemical behavior of compound

1 and 2, and of the

Au(I) complexes 11 was studied by cyclic voltammetry on a

9-

glassy carbon disc electrode in dichloromethane containing

Bu₄N[PF₆] as the supporting electrolyte.

In the structure of 10, both gold centers are linearly

coordinated and averted from each other because the central

ferrocene unit has an opened conformation with τ = −157.0(3)°

(N.B. the angle subtended by the Au1-Cl1 and Au2-Cl2 bonds is

Compound

1 (Figure 9) was oxidized in a single irreversible

step at 0.42 V vs. the ferrocene/ferrocenium reference couple

(anodic peak potential, E_pa, is given at a scan rate of 100 mV

s⁻¹), which corresponds with an electron-withdrawing nature

of the substituents at the ferrocene unit (cf. the Hammett σ_p

constant: 0.46 for –NC, and 0.19 for –PPh₂).⁴⁴This primary

redox change attributable to the oxidation of the ferrocene

moiety is followed by another irreversible redox event at a

139.26(6)°). Whereas the entire C1-N≡C11-Au2-Cl2 moiety is

essentially linear, the Au1-Cl1 bond diverts from the plane at

an angle of 23.1(2)°. On the other hand, the coordination

geometry parameters are not unexpected in view of the data

D

reported for [Au₂Cl₂(µ(P,P’)-dppf)]⁴²and [AuCl( -κP)].^12cIn the

more positive potential (E_pa

In contrast, the oxidation of amines

reversible (Figure 9). However, the waves were shifted to less

positive potentials (E°’ = −0.24 V and −0.13 V for and 2B

≈ 0.75 V).

crystal, the molecules of 10 assemble into head-to-tail dimers

via weak Au1···Au2 aurophilic interactions (3.21 Å; see the ESI,

Figure S12).⁴³

2

and 2B was

2

,

Finally, the reaction of [Au(tht)₂][SbF₆] with

1 (1 equiv.) or

respectively) due to the electron-donating nature of the amine

substituent (σ_p= −0.66). Even in this case, the first oxidations

were followed by irreversible processes at higher potentials.

removal of the chloride ligand from 9 with AgNTf₂resulted in

the formation of the respective dimeric complexes 11 (Scheme

6), which are the structural isomers of the recently reported

compounds [Au₂(µ(P,N)-D

)₂]X₂(X = SbF₆and NTf₂).^12bThe

dimeric structure of 11a and 11b was corroborated by X-ray

diffraction analysis (N.B. the structure of 11b could not be

−

adequately refined because of a severe disorder of the NTf₂

anion). The coordination of both donor moieties available in

ligand

1

is indicated by a shift of the ³¹P NMR signals to low

fields (δ_P32-33) and through a shift of the ν_{N C}bands in the IR

≡

spectra to higher energies (2231-2233 cm⁻¹). Notably, both

shifts are more pronounced than for the neutral complexes

9

and 10, very likely owing to a stronger interaction of the donor

moieties with the electron-poor cationic Au(I) centers.

The solid-state structure of 11a·2Me₂CO shown in Figure 8

resembles that of 7, except that the coordination of the Au

centers is practically undistorted linear (P-Au-C = 175.8(1)°).

The ferrocene cyclopentadienyl rings adopt a conformation

7 with τ of −80.0(3)°, which brings the linear

similar to that in

Figure 9. Cyclic voltammograms of amine

phosphino-isonitrile 1 (green – partial, and black – a wider scan) recorded with a glassy

carbon disc electrode in CH₂Cl₂(scan rate 0.1

s⁻¹). The second sweep in the

voltammogram of 1 is distinguished by a dashed line.

2 (blue), its BH₃adduct 2B (red) and

P-Au-NC subunits side-by-side (N.B. the angle subtended by

the P-Au and C11-Au’ bonds is only 4.17(1)°), though without

any supporting intramoleculars aurophilic interaction (Au···Au’

= 5.4400(4) Å).

V

The cyclic voltammogram of the monogold complex

two redox events in the anodic region, namely an irreversible

oxidation at E_pa0.61 V and a reversible redox process at E°’ =

9 showed

≈

0.78 V (Figure 10). Since the digold complex 10 displayed a

single reversible redox change at E°’ = 0.76 V, it appears likely

that the redox response of

9 can be affected by adsorption

phenomena. A single reversible redox event was observed also

for the dinuclear complexes 11a and 11b, whose behavior was

expectedly identical (E°’ = 0.79 V; see Figure 10).

Figure 8. View of the complex cation in the structure of 11a·2Me₂CO. Hydrogen atoms,

the counter anions and solvent molecules are omitted for clarity. Selected distances

and angles (in Å and deg): Au-P 2.2821(9), Au-C11’ 2.008(4), P-Au-C11’ 175.8(1), Au-

C11’-N’ 174.3(4), N-C11 1.135(5), C1-C11-N 173.4(4). The primed atoms are generated

by crystallographic inversion.

Electrochemistry

This journal is © The Royal Society of Chemistry 20xx

J. Name., 2013, 00, 1-3 | 7

Please do not adjust margins

Dalton Transactions

Page 8 of 16

View Article Online

DOI: 10.1039/C7DT02336G

ARTICLE

Journal Name

Tentatively, we ascribed the observed low catalytic activity of

the Au- complexes (particularly the dimers 11) to a relatively

1

stronger coordination of the isonitrile moiety, which prevents

the formation of coordinatively unsaturated Au(I) species by

dissociation of the Au-CN bonds. This assumption was

supported by the results of DFT computations performed on

the isolated cations [Au₂(µ(P,N)-L)₂]²⁺, where L =

4), which indeed revealed that the dissociation of the

phosphinonitrile-bridged dimers (L = ) to the monomeric

species [Au(

)]⁺is by approximately 12 kcal mol^–1less

endergonic than for the corresponding dimeric cation

containing the isomeric ligand

(27.2 vs. 39.4 kcal mol^–1).⁴⁵

D or 1 (Table

D

1

Table 4. Comparison of the experimental (from X-ray diffraction analysis) and DFT

computed structural parameters for cations [Au₂(µ(P,N)-L)₂]²⁺(L = D or 1).

[Au₂(µ(P,N)-D)₂]²⁺

[Au₂(µ(P,N)-1)₂]²⁺

Parameter

X-Ray^b

DFT

Parameter

X-Ray^c

DFT

Figure 10. Cyclic voltammograms of complexes 9 (blue, the second scan is shown as a

dashed line), 10 (red) and 11a (green) as recorded with a glassy carbon disc electrode

in CH₂Cl₂(scan rate 0.1 V s⁻¹).

Au–N

C≡N

2.035(4)

1.139(8)

2.225(2)

175.1(2)

168.2(5)

2.054

1.160

2.281

175.7

170.6

Au–C

N≡C

2.008(4)

1.135(5)

2.282(1)

175.8(1)

174.3(4)

1.996

1.164

2.333

175.3

175.4

Au–P

N–Au–P

Au–N–C

C–Au–P

Au–C–N

Catalytic tests with Au(I)-1 complexes

Considering the favorable catalytic properties of gold(I)

complexes with ligand D ^12b

a

The calculations were performed at the PBE0/cc-pVDZ:sdd(Fe,Au) level of

,

we decided to probe the catalytic

theory using the PCM model to treat possible solvent effects (CHCl₃). For details,

see Experimental. ^bData from ref. 12b, SbF₆⁻salt. ^cThis work; SbF₆⁻salt.

properties of the isomeric compounds featuring ligand 1. For

testing, we chose the gold-catalyzed cyclization of unsaturated

alcohol 12 to give 2,3-dimethylfurane (13; Scheme 7) that has

been used to evaluate the catalysts based on ligand D.

Conclusions

The discovery of a practical and reliable synthesis of 1´-

[Au]

OH

(diphenylphosphino)-1-aminoferrocene (2) and its P-protected

O

13

analogues (the borane adduct 2B in particular) reported in this

contribution opens a way to further synthetic utilization of this

versatile but long ignored phosphinoferrocene building block.

12

Scheme 7. Au-Catalyzed cycloisomerisation of enynol 12 to 2,3-dimethylfurane.

Herein, the synthetic use of

2 is demonstrated by the synthesis

Unfortunately, the collected results (Table 3) indicate a

generally very low (if any at all) catalytic activity of the

of phosphino-isonitrile 1, representing a new entry among the

still uncommon donors of this type. As revealed by our

coordination study with Ag(I) and Au(I) ions with and without

auxiliary chloride ligands (N.B. defined Cu(I) complexes were

not isolated despite numerous attempts), the ferrocene

prepared Au-

1 complexes. For instance, compound 10

achieved a 82% yield of the cyclization product 13 after 30 min

and a nearly 90% yield after 3 h at 1 mol.% Au loading. These

yields decreased substantially upon lowering the catalyst

moiety in the structure of

1 behaves as a molecular ball

amount to 0.1 mol.%. The monogold complex

9 and,

bearing connecting the two sterically distinct, soft donor

moieties present in this ligand, allowing their orientation into

positions appropriate for the formation of discrete, dimeric

and even polymeric assemblies. Compared to the isomeric

surprisingly, also the dimers 11 proved to be catalytically

inactive, which markedly contrasts with the very high catalytic

activity of [Au₂(µ(P,N)-D

)₂]X₂(X = SbF₆, NTf₂).^12b

Table 3. Summary of the catalytic results.^a

phosphino-nitrile donor

also more strongly) coordinated through its isonitrile donor

group. However, the stronger Au CN bonding can be made

D, ligand 1 becomes more easily (and

Au loading

Yield of 13 after

Complex

[mol.%]

−

30 min [%]

3 h [%]

responsible for a lower catalytic activity of the dimeric Au(I)

complexes 11, very likely due to a suppressed dissociation of

these dimers into monogold(I) species. Further studies into the

coordination behavior and possible synthetic applications of

9

1.0

0.1

1.0

0

82

64

0

89

75

0

10

11a

11b

0

phosphino-isonitrile

1 focused mainly at its insertion chemistry

a

are currently underway.

Compound 12 (1 mmol) and 1,2-dichloroethane (internal standard; 1 mmol)

were dissolved in CDCl₃(2 mL). The respective catalyst was added and the

reaction mixture was stirred at room temperature for a given time (the amount

of the starting materials was doubled for reactions with 0.1 mol.% Au). The yields

were determined by integration of ¹H NMR spectra.

Experimental

8 | J. Name., 2012, 00, 1-3

This journal is © The Royal Society of Chemistry 20xx

Please do not adjust margins

Dalton Transactions

Page 9 of 16

Journal Name

View Article Online

DOI: 10.1039/C7DT02336G

ARTICLE

Materials and Methods. All syntheses were performed under stirred at 0

an argon atmosphere using standard Schlenk techniques and 2 h. Then, it was diluted with saturated aqueous NaHCO₃(40

with protection from the direct sun light. Compounds 3S ⁴⁶

4- mL) and diethyl ether (80 mL). The organic phase was

toluenesulfonyl azide,⁴⁷acetic formic anhydride,⁴⁸[AuCl(tht)]⁴⁹separated and the aqueous one was extracted with diethyl

and [Au(tht)₂][SbF₆]^12bwere prepared according to the ether (3

40 mL). The combined organic layers were washed

°C for 30 min and at room temperature for another

,

×

literature. Chloro-diphenylphosphine was distilled under with brine and dried over MgSO₄. The dried solution was

vacuum. Anhydrous dichloromethane and tetrahydrofuran evaporated with chromatographic silica gel and the crude pre-

were obtained from a PureSolv MD5 solvent purification adsorbed product was transferred to a silica gel column.

system (Innovative Technology, MA, USA). Toluene was dried Elution with diethyl ether-hexane (1:3) provided an orange

over sodium metal and distilled. Other chemicals and solvents band containing the product. Evaporation afforded compound

utilized for crystallizations and during chromatography were of 4S as an orange oil (2.15 g, ca. 75%), which usually contained

reagent grade (Sigma-Aldrich and Alfa-Aesar; solvents from unreacted TsN₃(less than 5 mol.%) and FcP(S)Ph₂(typically ca.

Lach-Ner, Czech Republic) and were used without additional 20 mol%; Fc = ferrocenyl) formed by protonation of the

purification.

lithiated intermediate. Crystals used for single-crystal X-ray

The NMR spectra were recorded at 25 °C on a Varian UNITY diffraction analysis were grown from diethyl ether. The

Inova 400 or a Bruker Avance III 400 spectrometer. Chemical product decomposes (darkens) upon prolonged storage (even

shifts (δ in ppm) are given relative to an internal when stored in a refrigerator and in the dark). If appropriate, it

tetramethylsilane (¹H and ¹³C) and an external 85% H₃PO₄can be easily purified by chromatography as described above.

standard (³¹P), all set to 0 ppm. In addition to the usual ¹H NMR (CDCl₃): δ 4.07 (vt, J

notation of signal multiplicity, vt and vq are used to distinguish Hz, 2 H, fc), 4.54 (vq, J = 2.1 Hz, 2 H, fc), 4.63 (vq, J

virtual triplets and quartets due to ferrocene protons H, fc), 7.40-7.51 (m, 6 H, P(S)Ph₂), 7.69-7.75 (m, 4 H, P(S)Ph₂).

constituting the AA BB and AA BB

X spin systems in the ¹³C{¹H} NMR (CDCl₃): δ 62.07 (CH of fc), 67.82 (CH of fc), 73.19

′

= 2.0 Hz, 2 H, fc), 4.23 (vt, J

′ = 2.0

′

= 2.1 Hz, 2

′

nitrogen- and PPh₂-substituted cyclopentadienyl rings, (d, J = 10 Hz, CH of fc), 73.84 (d, J = 12 Hz, CH of fc), 100.51

respectively (fc

=

ferrocene-1,1

′

-diyl). FTIR spectra were (C^ipso-N₃of fc), 128.26 (d, ²J_PC= 12 Hz, CH^orthoof Ph), 131.31 (d,

measured with a Nicolet 6700 spectrometer in a range of 400- ⁴J_PC= 2 Hz, CH^paraof Ph), 131.59 (d, J_PC= 10 Hz, CH^metaof Ph),

4000 cm^–1. Electrospray ionization (ESI) mass spectra were 134.36 (d, ¹J_PC= 87 Hz, C^ipsoof Ph). The signals due to C^ipso-P of

obtained on an Esquire 3000 (Bruker) spectrometer using fc was not found. ³¹P{¹H} NMR (CDCl₃): δ 41.7 (s). IR (Nujol):

samples dissolved in HPLC-grade methanol. High resolution ν_max3049 w, 2109 s (N₃), 1308 w, 1287 m, 1193 w, 1170 m,

(HR) measurements were performed with an LTQ Orbitrap XL 1102 s, 1069 w, 1026 m, 998 w, 917 w, 837 m, 828 m, 754 m,

spectrometer (Thermo Fisher Scientific). The assignment of the 716 s, 695 s, 656 s, 629 w, 615 w, 541 m, 523 m, 496 m, 448 w

observed ions was based on a comparison of the theoretical cm⁻¹. ESI+ MS: m/z 438 ([M – N₂+ Na]⁺), 466 ([M + Na]⁺).

and experimental isotopic patterns. Elemental analyses were HRMS calc. for C₂₂H₁₈⁵⁶FeN₃PS (M⁺): 443.0308, found

3

determined with a Perkin-Elmer PE 2400 CHN analyzer.

443.0309.

The cyclic voltammograms were recorded with a ꢀAUTOLAB III Synthesis of 5 from 4S. An aqueous suspension of active Raney

instrument (Eco Chemie, The Netherlands) at ambient nickel (Sigma-Aldrich, type 2400) corresponding to 8 g of the

temperature using samples dissolved in dry dichloromethane solid material was transferred to a reaction flask and washed

(sample concentration 0.5 mM or a saturated solution in the with reagent grade and then anhydrous THF (5-times each)

case of poorly soluble complexes) and Bu₄N[PF₆] as the under argon. The remaining solid was suspended in anhydrous

supporting electrolyte (0.1 M). A glassy carbon disc (2 mm THF (25 mL) and a solution of impure 4S (0.800 g; this amount

diameter) was employed as a working electrode, Ag/AgCl (3 M corresponds to 1.8 mmol of pure 4S) in 10 mL of dry THF was

LiCl/EtOH) as a reference electrode and platinum sheet as a added (an effervescence was observed during the addition).

counter electrode. Decamethylferrocene was added as an The reaction mixture was stirred at room temperature for 3

internal reference for the final scans but the potentials were days and filtered through a Celite pad, which was then washed

converted to the ferrocene/ferrocenium scale by subtracting with THF (3

by 0.548 V.⁵⁰

× 15 mL). Neat acetic formic anhydride (HCOOAc;

0.8 mL, 10 mmol) was added to the filtrate and the resultant

Synthesis of 4S. An oven-dried two-necked flask was charged reaction mixture was stirred at ambient temperature for 3 h

with 3S (2.40 g, 5.0 mmol) and a magnetic stirring bar, flushed before quenching with saturated aqueous NaHCO₃. After gas

with argon and sealed a rubber septum. Dry THF (80 mL) was evolution had ceased, the mixture was extracted with diethyl

introduced under argon to dissolve the solid and the flask was ether (50 mL). The organic layer was washed with water and

cooled in an ice bath with continuous stirring. n-Butyllithium brine, dried over MgSO₄and evaporated, leaving an orange

(2.0 mL 2.5 M, 5.0 mmol) was added and the mixture was residue, which was purified by column chromatography (silica

allowed to react for 20 min with continuous cooling. Neat 4- gel, ethyl acetate-hexane 1:1). The first orange band

toluenesulfonyl azide (TsN₃; 986 mg, 5.0 mmol) was containing FcPPh₂and some tosylated impurities was followed

introduced to the lithiated intermediate, causing the reaction by an orange band containing the desired product

mixture to turn red (Note: TsN₃was stored over CaH₂prior to contaminated by traces of FcNHCHO.⁵The second band was

the use. Reactions with the untreated commercial reagent evaporated and the residue chromatographed again to afford

gave considerably lower yields). The reaction mixture was pure

5

(orange solid; 0.253 g or 34% with respect to 2S

This journal is © The Royal Society of Chemistry 20xx

J. Name., 2013, 00, 1-3 | 9

Please do not adjust margins

Dalton Transactions

Page 10 of 16

View Article Online

DOI: 10.1039/C7DT02336G

ARTICLE

Journal Name

available in the starting material) and FcNHCHO (orange solid; Hz, 2 H, fc), 4.55 (vdt, J = 1.8 Hz, 1.2 Hz, 2 H, fc), 7.39-7.50 (m,

55 mg, 13% with respect to 2S). The yield did not practically 6 H, PPh₂), 7.55-7.61 (m, 4 H, PPh₂). ¹³C{¹H} NMR (CDCl₃): δ

′

1

change when the reaction time was shortened to 1 day. 69.44 (CH of fc), 70.49 (d, J_PC= 68 Hz, C^ipso-P of fc), 71.67 (CH

Compound

5 was obtained as a mixture of (Z) and (E) isomers of fc), 74.87 (d, J_PC= 9 Hz, CH of fc), 75.47 (d, J_PC= 7 Hz, CH of

2

in 5:4 ratio. Crystals of (Z)-

5

were obtained by recrystallization fc), 77.72 (C^ipso-Br of fc), 128.50 (d, J_PC= 10 Hz, CH^orthoof Ph),

from chloroform/hexane.

130.96 (d, ¹J_PC= 60 Hz, C^ipsoof Ph), 131.01 (d, ⁴J_PC= 2 Hz, CH^para

Notably, when the reaction was performed in dry acetonitrile, of Ph), 132.61 (d, J_PC= 9 Hz, CH^metaof Ph). ³¹P{¹H} NMR

3

the unwanted dephosphorylation leading to FcNHCHO was (CDCl₃): δ 16.2 (br d, J ≈ 75 Hz). IR (Nujol): ν_max3102 w, 3073 w,

suppressed but the yield of

5 was only 13%. Practically no 3056 w, 2398 s (BH₃), 2373 s (BH₃), 2344 m (BH₃), 1350 m,

desulfurization (only conversion of the azide to formamide) 1309 m, 1195 m, 1181 m, 1172 s, 1157 w, 1132 w, 1108 s,

was observed in 1,2-dimethoxyethane under similar conditions 1063 s, 1026 s, 1000 m, 978 w, 930 w, 895 w, 872 s, 838 s, 828

(room temperature, 3 days), while in anhydrous ethanol the w, 818 m, 766 w, 743 s, 703 s, 696 s, 643 s, 622 w, 610 m, 568

starting azide was converted to the N-alkylated products w, 527 m, 506 s, 496 s, 476 s, 461 s, 440 m (cm⁻¹). ESI+ MS:

FcN(Et)CHO and Ph₂PfcN(Et)CHO in ca. 1:1 ratio (ESI+ MS data m/z 448 ([M – BH₃+ H]⁺), 485 ([M + Na]⁺). Anal. Calc. for

for Ph₂PfcN(Et)CHO: m/z 442 ([M + H]⁺), 464 ([M + Na]⁺), 480 C₂₂H₂₁BBrFeP (462.9): C 57.08, H 4.57. Found: C 57.32, H

([M + K]⁺).

4.55%.

1

. H NMR (CDCl₃): major

Analytical data for

5

−

δ 3.96 (vt, J

′

=

Synthesis of 3B from 1,1’-dibromoferrocene. An oven-dried

2.0 Hz, 2 H, fc), 4.08 (br s, 2 H, fc), 4.44 (vt, J

4.52 (vt, J = 1.8 Hz, 2 H, fc), 6.10 (br s, 1 H, NH), 7.30-7.42 (m, (17.1 g, 50 mmol), flushed with argon and sealed. Dry THF (200

10 H, PPh₂), 7.94 (d, J_HH= 1.5 Hz, 1 H, CHO); minor

(vt, J = 2.0 Hz, 2 H, fc), 4.13 (vq, J = 1.7 Hz, 2 H, fc), 4.16 (vt, J

= 2.0 Hz, 2 H, fc), 4.42 (vt, J

= 1.8 Hz, 2 H, fc), 6.65 (br d, ³J_HH

′ = 1.8 Hz, 2 H, fc), round bottom flask was charged with 1,1’-dibromoferrocene

′

3

−

δ 3.99 mL) was introduced and the solution was cooled in a dry

′

=

ice/ethanol bath to ca.

in hexanes, 50 mmol) was introduced and the resultant

78 C for 60 min during which time an

δ 63.22 (CH of fc), orange precipitate formed. Chloro-diphenylphosphine (9.9 mL,

65.97 (CH of fc), 72.23 (CH of fc), 74.26 (d, J_PC= 8 Hz, CH of fc), 55 mmol) was added, whereupon the precipitate dissolved.

−78 °C. n-Butyllithium (20 mL of 2.5 M

′

11.7 Hz, 1 H, NH), 7.30-7.42 (m, 10 H, PPh₂), 8.20 (d, ³J_HH= 11.7 mixture was stirred at

Hz, 1 H, CHO). ¹³C{¹H} NMR (CDCl₃): major

−

°

−

75.99 (br s, C^ipso-P of fc), 92.54 (C^ipso-N of fc), 128.30 (d, ³J_PC= 7 The mixture was stirred at

−78 °C for 30 min and then at room

Hz, CH^metaof Ph), 128.55 (CH^paraof Ph), 133.47 (d, ²J_PC= 20 Hz, temperature overnight before it was treated with neat

CH^orthoof Ph), 139.12 (d, J_PC= 9 Hz, C^ipsoof Ph), 159.02 (CHO); BH₃·SMe₂(6.3 mL, 65 mmol). Stirring was continued for 1 h

1

minor − δ 62.88 (CH of fc), 66.76 (CH of fc), 72.21 (CH of fc), and the reaction mixture was diluted by saturated aqueous

74.16 (d, J_PC= 8 Hz, CH of fc), 93.74 (C^ipso-N of fc), 128.30 (d, NaHCO₃and ethyl acetate (50 mL each). The organic layer was

³J_PC= 7 Hz, CH^metaof Ph), 128.82 (CH^paraof Ph), 138.58 (d, ²J_PC

=

separated, washed with water and brine, dried over MgSO₄

20 Hz, CH^orthoof Ph), 138.58 (d, J_PC= 9 Hz, C^ipsoof Ph), 163.06 and, finally, evaporated with silica gel. The preadsorbed

(CHO). The signal due to C^ipso-P of fc for the minor isomer material was transferred to a silica gel column, which was

appears to be obscured by the solvent resonance. ³¹P{¹H} NMR eluted first with dichloromethane-hexane (1:5) to remove

(CDCl₃): δ –17.5 (s, major), –16.8 (s, minor). IR (Nujol): ν_maxbromo- and 1,1’-dibromoferrocene (ca. 0.45 g). Then, the

3260 m, 3095 m, 3057 w, 1663 s (CHO), 1561 m, 1263 m, 1211 eluent was gradually changed to pure dichloromethane, which

1

w, 1193 w, 1164 m, 1094 w, 1069 w, 1033 m, 1023 m, 922 m, removed

a major orange brown band containing 3B.

853 m, 832 m, 805 m, 755 s, 741 s, 704 s, 697 s, 633 w, 529 w, Evaporation and crystallization from hot ethyl acetate-hexane

497 s, 486 s, 460 m, 435 w cm⁻¹. ESI+ MS: m/z 414 ([M + H]⁺), (ca. 1:2 mixture) afforded analytically pure 3B as an orange

436 ([M + Na]⁺), 452 ([M + K]⁺). HRMS calc. for C₂₃H₂₀⁵⁶FeNOP crystalline solid. Yield: 19.5 g (84%), two crops.

(M⁺): 413.0632, found 413.0631. Anal. Calc. for C₂₃H₂₀FeNOP Synthesis of 4B. Compound 3B (4.63 g, 10.0 mmol) was

(413.2): C 66.85, H 4.88, N 3.39%. Found: C 66.83, H 4.91, N dissolved in dry THF (100 mL) in an oven-dried reaction flask,

3.37%.

which was then cooled in dry ice/ethanol bath to ca.

SMe₂solution (6 mL of 2 M in Butyllithium (4.0 mL of 2.5 M in hexanes, 10 mmol) was added

(4.47 g, and the reaction mixture, which gradually deposited an orange

10.0 mmol) in dry THF (30 mL) and the mixture was stirred at precipitate, was stirred at 78 C for 30 min. Neat TsN₃(1.97 g,

−78 °C. n-

Synthesis of 3B from 3. A BH₃

⋅

THF, 12 mmol) was added to a solution of compound

3

−

°

room temperature under argon for 90 min. Methanol (0.5 mL) 10 mmol; see comments below) was introduced and the

was added to destroy an excess of borane and, after gas resulting mixture was stirred at room temperature for 2 h

evolution had subsided (5 min), the reaction mixture was (Note: the solid precipitate dissolved and the color of the

evaporated with chromatographic silica gel. The preadsorbed reaction mixture changed to red). The reaction was terminated

product was transferred to a short silica gel column. Elution by addition of water (10 mL) and the mixture was transferred

with toluene-hexane (1:1) and evaporation of a single orange to a separatory funnel. The aqueous layer was separated and

band provided the protected phosphine 3B as an orange solid extracted with diethyl ether (3× 30 mL). The organic layers

(4.39 g, 95%). Note: Elution with toluene makes the workup were combined, washed with brine, dried over MgSO₄and

faster but the product contains some foul smelling impurities.

¹H NMR (CDCl₃): δ 0.8-1.7 (very br m, 3 H, BH₃), 4.08 (vt, J

evaporated. The obtained brown oil was purified by column

chromatography over silica gel using diethyl ether-hexane (1:1)

′

= 1.8 as the eluent (Note: the crude product should not be

=

1.9 Hz, 2 H, fc), 4.33 (vt, J

′

= 1.9 Hz, 2 H, fc), 4.46 (vq, J

′

10 | J. Name., 2012, 00, 1-3

Please do not adjust margins

Dalton Transactions

Page 11 of 16

Journal Name

View Article Online

DOI: 10.1039/C7DT02336G

ARTICLE

exhaustively evaporated to avoid formation of a gummy H, BH₃), 4.01 (vt, J′ = 1.9 Hz, 2 H, fc), 4.25 (vt, J

product, which is poorly soluble in the mobile phase). A single fc), 4.41 (vq, J = 1.8 Hz, 2 H, fc), 4.58 (vdt, J

′ = 2.0 Hz, 2 H,

′

orange band was collected and evaporated under vacuum to H, fc), 6.74 (br s, 1 H, NH), 7.39-7.52 (m, 6 H, PPh₂), 7.56-7.63

= 1.9 Hz, 1.2 Hz, 2

3

afford 4B as an orange microcrystalline solid (3.78 g, 89%). (m, 4 H, PPh₂), 8.14 (d, J_HH= 11.6 Hz, 1 H, CHO). ¹³C{¹H} NMR

Crystals of 4B used for structure determination were grown by (CDCl₃): major

− δ 63.90 (CH of fc), 66.15 (CH of fc), 69.22 (d,

diffusion of hexane into a diethyl ether solution at 4

°C.

¹J_PC= 69 Hz, C^ipso-P of fc), 73.15 (d, J_PC= 8 Hz, CH of fc), 74.22

Note: TsN₃must be dried by stirring with CaH₂freshly prior to (d, J_PC= 10 Hz, CH of fc), 93.59 (C^ipso-N of fc), 128.54 (d, J_PC

=

2

the use (preferably overnight). Only if such carefully dried TsN₃10 Hz, CH^orthoof Ph), 130.95 (d, ¹J_PC= 60 Hz, C^ipsoof Ph), 131.04

is used, the reaction product is contaminated by less than 5 (d, ⁴J_PC= 2 Hz, CH^paraof Ph), 132.65 (d, ³J_PC= 9 Hz, CH^metaof Ph),

mol.% of FcPPh₂·BH₃. Otherwise, the amount of FcPPh₂·BH₃159.12 (CHO); minor

1

−

δ 62.56 (CH of fc), 67.17 (CH of fc),

and unreacted TsN₃are higher. Azide 4B does not decompose 70.18 (d, J_PC= 68 Hz, C^ipso-P of fc), 73.28 (d, J_PC= 8 Hz, CH of

when stored in the dark at 4 °

C for weeks. If necessary, it can fc), 74.21 (d, J_PC= 10 Hz, CH of fc), 95.04 (C^ipso-N of fc), 128.59

be purified by column chromatography as specified above.

(d, J_PC= 10 Hz, CH^orthoof Ph), 130.82 (d, J_PC= 60 Hz, C^ipsoof

2

1

¹H NMR (CDCl₃): δ 0.8-1.6 (very br m, 3 H, BH₃), 4.00 (vt, J

′ =

2.0 Hz, 2 H, fc), 4.16 (vt, J

Ph), 131.19 (d, ⁴J_PC= 2 Hz, CH^paraof Ph), 132.57 (d, ³J_PC= 10 Hz,

′ = 2.0 Hz, 2 H, fc), 4.52 (vq, J′

= 1.8 CH^metaof Ph), 162.39 (CHO). ³¹P{¹H} NMR (CDCl₃): 16.1 (br d,

= 1.8 Hz, 1.1 Hz, 2 H, fc), 7.38-7.50 (m, both isomers). IR (Nujol): ν_max3275 br m, 3230 br m, 3082 m,

Hz, 2 H, fc), 4.65 (vdt, J

′

6 H, PPh₂), 7.56-7.62 (m, 4 H, PPh₂). ¹³C{¹H} NMR (CDCl₃): δ 3054 m, 2374 s (BH₃), 2343 m (BH₃), 1687 m, 1663 s (CHO),

61.85 (CH of fc), 67.50 (CH of fc), 70.12 (d, J_PC= 68 Hz, C^ipso-P 1582 m, 1564 s, 1353 w, 1310 w, 1267 w, 1258 w, 1173 s, 1133

1

of fc), 73.33 (d, J_PC= 8 Hz, CH of fc), 73.70 (d, J_PC= 10 Hz, CH of w, 1107 m, 1057 s, 1029 s, 999 w, 927 w, 837 w, 830 w, 813 w,

fc), 100.41 (C^ipso-N₃of fc), 128.49 (d, ²J_PC= 10 Hz, CH^orthoof Ph), 759 w,, 744 s, 701 s, 636 m, 623 w, 612 w, 528 m, 500 s, 475 s,

131.00 (d, ⁴J_PC= 2 Hz, CH^paraof Ph), 131.01 (d, ¹J_PC= 60 Hz, C^ipso463 w, 447 w cm⁻¹. ESI+ MS: m/z 450 ([M + Na]⁺), 466 ([M +

3

of Ph), 132.58 (d, J_PC= 9 Hz, CH^metaof Ph). ³¹P{¹H} NMR K]⁺). HRMS calc. for C₂₃H₂₃B⁵⁶FeNOP (M⁺): 427.0960, found

(CDCl₃): δ 16.2 (br d). IR (Nujol): ν_max3077 w, 3054 w, 2382 s 427.0965. Anal. Calc. for C₂₃H₂₃BFeNOP (427.0): C 64.68, H

(BH₃), 2338 m (BH₃), 2108 s (N₃), 1314 w, 1285 s, 1223 w, 1176 5.43, N 3.28%. Found: C 64.50, H 5.08, N 3.23%.

s, 1161 m, 1134 m, 1107 s, 1061 s, 1036 m, 1028 s, 999 w, 920 Synthesis of 5 from 5B. A dry reaction flask was charged with

w, 832 s, 820 m, 760 m, 741 s, 703 s, 692 m, 635 m, 625 m, 611 5B (1.28 g, 3.0 mmol), 1,4-diazabicyclo[2.2.2]octane (0.449 g,

m, 595 w, 528 s, 489 s, 463 m, 446 w, 409 w cm⁻¹. ESI+ MS: 4.0 mmol) and a stirring bar, flushed with argon and sealed

m/z 420 ([M – N₂+ Na]⁺), 448 ([M + Na]⁺). HRMS calc. for with a rubber septum. Dry toluene (60 mL) was added and the

C₂₂H₂₁B⁵⁶FeN₃P (M⁺): 425.0916, found 425.0921.

reaction flask was transferred to an oil bath maintained at 80

°C. After stirring for 20 h, the mixture was evaporated under

dry THF (40 mL) was slowly introduced to a reaction flask reduced pressure. The residue was dissolved in a minimal

Synthesis of 5B for 4B. A solution of 4B (1.70 g, 4.0 mmol) in

containing Li[AlH₄] (0.304 g, 8.0 mmol) while stirring and amount of THF and purified by column chromatography (silica

cooling on ice (gas evolution was noted). After the addition gel, ethyl acetate-hexane 1:1) to afford formamide

5 as an

was complete, the cooling bath was removed and the mixture amber brown, slowly crystallizing oil. Yield: 1.17 g (94%).

was stirred at room temperature for 3 h before an excess of Synthesis of 2B. A solution of azide 4B (1.70 g, 4.0 mmol) in

the reducing agent was destroyed by a careful addition of 10% dry THF (40 mL) was added to an ice-cooled reaction flask

aqueous NaOH (0.5 mL) and stirring for 10 min. Anhydrous containing Li[AlH₄] (0.304 g, 8.0 mmol) and a stirring bar (an

MgSO₄(1 g) was added and the pasty mixture was transferred effervescence was observed). When the addition was

to a Celite pad on a glass frit. Washing with dry THF (60 mL in complete, the cooling bath was removed and stirring was

several portions) provided an orange filtrate, which was continued at room temperature for 3 h. The reaction was

treated with formic acetic anhydride (1.0 mL, 12.8 mmol) in an terminated by cautious addition of 10% aqueous NaOH (0.5

argon-flushed vessel. The resultant mixture was stirred at mL) and, after stirring for another 10 min, anhydrous MgSO₄(1

room temperature for 3 h and then diluted with saturated g). The obtained semisolid mass was transferred to a Celite

aqueous NaHCO₃and diethyl ether (50 mL each). The organic pad on a glass frit and washed with dry THF (60 mL in several

layer was separated, washed with water and brine, dried over portions). The orange filtrate was evaporated to afford an

MgSO₄and evaporated. The crude product was purified by orange brown oil, which was purified by chromatography over

chromatography on a silica gel column with ethyl acetate- a short silica gel using ethyl acetate-hexane (1:3) as the eluent,

hexane (1:1) as the eluent. The first yellow band containing which removed some non-polar impurities. A subsequent

impurities was discarded and the second (major) one was elution with ethyl acetate-hexane (1:1) provided a deep

collected and evaporated to afford 5B as an orange oil, which orange band containing the product. Evaporation of this band

gradually solidified. Yield: 1.50 g (88%). The product is a afforded amine 2B as an orange oil, which gradually solidified.

mixture of (E) and (Z) isomers in ca. 2:1 ratio.

¹H NMR (CDCl₃): major

δ 0.8-1.7 (very br m, 3 H, BH₃), 3.90 decomposition when stored at 4

(vt, J = 2.0 Hz, 2 H, fc), 4.29 (vq, J = 1.8 Hz, 2 H, fc), 4.59 (vdt, J decomposes in chlorinated solvents.

= 1.8 Hz, 1.2 Hz, 2 H, fc), 4.69 (vt, J

= 2.0 Hz, 2 H, fc), 6.71 (br s, ¹H NMR (CDCl₃): δ 0.8-1.7 (very br m, 3 H, BH₃), 2.51 (br s, 2 H,

1 H, NH), 7.39-7.52 (m, 6 H, PPh₂), 7.56-7.63 (m, 4 H, PPh₂), NH₂), 3.71 (vt, J = 1.9 Hz, 2 H, fc), 3.97 (vt, J = 1.9 Hz, 2 H, fc),

8.06 (d, ³J_HH= 1.1 Hz, 1 H, CHO); minor

δ 0.8-1.7 (very br m, 3 4.25 (vq, 2 H, J = 1.8 Hz, 2 H, fc), 4.48 (v dt, J = 1.8 Hz, 1.1 Hz,

Yield: 1.49 g (93%). Note: solid 2B does not show any signs of

−

°C in the dark but readily

′

−

′

J. Name., 2013, 00, 1-3 | 11

Please do not adjust margins

Dalton Transactions

Page 12 of 16

View Article Online

DOI: 10.1039/C7DT02336G

ARTICLE

Journal Name

2 H, fc), 7.38-7.48 (m, 6 H, PPh₂), 7.58-7.64 (m, 4 H, PPh₂). this time and the mixture slightly darkened). The resulting

¹³C{¹H} NMR (CDCl₃): δ 59.76 (CH of fc), 64.76 (CH of fc), 68.42 solution was diluted with diethyl ether (10 mL), washed

(d, J_PC= 70 Hz, C^ipso-P of fc), 72.48 (d, J_PC= 8 Hz, CH of fc), successively with saturated aqueous NaHCO₃, water and brine,

73.78 (d, ²J_PC= 10 Hz, CH of fc), 107.37 (C^ipso-N of fc), 128.39 (d, dried over MgSO₄and concentrated under vacuum. The

²J_PC= 10 Hz, CH^orthoof Ph), 130.82 (d, ⁴J_PC= 2 Hz, CH^paraof Ph), residue was taken up in a minimal amount of THF and

1

3

1

3

131.54 (d, J_PC= 59 Hz, C^ipso-P of Ph), 132.62 (d, J_PC= 9 Hz, transferred to a short silica gel column. Elution with diethyl

CH^metaof Ph). ³¹P{¹H} NMR (CDCl₃): δ 16.4 (br d). IR (Nujol): ν_maxether-hexane (1:1) led to the development of an orange band,

3416 m, 3385 m, 3332 m, 3076 m, 3058 w, 2380 s (BH₃), 2255 which was collected and evaporated under vacuum to afford

1

w (BH₃), 1503 s (NH₂), 1305 w, 1252 w, 1194 w, 1173 s, 1134 as as an orange microcrystalline solid emitting an unpleasant

m, 1106 s, 1060 s, 1041 m, 1026 s, 998 w, 934 w, 850 m, 817 s, odor typical of isonitriles. Yield: 281 mg (71%). Notes: A further

796 m, 767 m, 744 s, 735 s, 700 s, 689 s, 637 s, 621 m, 613 m, elution with ethyl acetate recovered some unreacted (impure)

529 m, 502 s, 471 s, 460 m, 442 w, 417 w, 411 w cm⁻¹. ESI+ amide

5. The yield of 1 decreased when the reaction was

MS: m/z 398 ([M – H]⁺). HRMS calc. for C₂₂H₂₃B⁵⁶FeNP (M⁺): carried out in incompletely dried THF and without rigorous

399.1011, found 399.1018. Anal. Calc. for C₂₂H₂₃BFeNP (399.0): exclusion of air and moisture.

¹H NMR (CDCl₃): δ 4.02 (vt, J

C 66.21, H 5.81, N 3.51%. Found: C 66.10, H 5.93, N 3.50%.

Synthesis of amine 2. Compound 2B (0.399 mg, 1.0 mmol) and Hz, 2 H, fc), 4.43 (vt, J

′

= 1.9 Hz, 2 H, fc), 4.22 (vq, J

′ = 1.9

′

= 2.0 Hz, 2 H, fc), 4.51 (vt, J = 1.9 Hz, 2

′

1,4-diazabicyclo[2.2.2]octane (0.224 g, 2.0 mmol) were H, fc), 7.31-7.38 (m, 10 H, PPh₂). ¹³C{¹H} NMR (CDCl₃): δ 67.61

dissolved in 20 mL of dry toluene in a dry reaction flask under (CH of fc), 68.19 (CH of fc), 73.92 (d, J_PC= 4 Hz, CH of fc), 74.96

argon. The reaction mixture was stirred at room temperature (d, J_PC= 14 Hz, CH of fc), 78.78 (d, J_PC= 9 Hz, C^ipso-P), 128.31 (d,

for 18 h and then evaporated under vacuum. A brown residue ³J_PC= 7 Hz, CH^metaof Ph), 128.79 (CH^paraof Ph), 133.42 (d, ²J_PC

was dissolved in a minimal amount of THF and purified by 20 Hz, CH^orthoof Ph), 138.27 (d, ¹J_PC= 10 Hz, C^ipsoof Ph), 164.30

column chromatography (silica gel, ethyl acetate-hexane 1:1). (NC). The resonance due to ferrocene C^ipso-NC is probably

=

Evaporation of a single orange band furnished pure amine

2

as obscured by the solvent signal. ³¹P{¹H} NMR (CDCl₃): δ −17.8

1

an orange solid (0.362 g, 94%). The compound is stable as a (s). H NMR (acetone-d₆): δ 4.10 (vt, J

′

= 2.0 Hz, 2 H, fc), 4.23

= 2.1 Hz, 2 H, fc), 4.59 (vt, J

solvents. It can be practically quantitatively recrystallized from = 1.8 Hz, 2 H, fc), 7.37-7.41 (m, 10 H, PPh₂). ³¹P{¹H} NMR

hot hexane, which was also used to grow single crystals. (acetone-d₆): δ −17.3 (s). IR (Nujol): ν_max3114 w, 3054 w, 2126

¹H NMR (CDCl₃): δ 2.25 (br s, 2 H, NH₂), 3.78 (vt, J

= 1.8 Hz, 2 s (N C), 1231 w, 1193 w, 1160 m, 1089 w, 1028 s, 999 w, 916

H, fc), 3.90 (vt, J = 1.7 Hz, 2 H, fc), 4.00 (vt, J = 1.8 Hz, 2 H, fc), w, 836 m, 819 s, 747 s, 698 s, 639 w, 596 w, 531 w, 510 s, 502

4.33 (vt, J

solid but gradually decomposes when dissolved in chlorinated (vq, J

′

= 1.8 Hz, 2 H, fc), 4.57 (vt, J

′

≡

′

= 1.6 Hz, 2 H, fc), 7.28-7.34 (m, 6 H, PPh₂), 7.36-7.43 m, 488 m, 458 w, 432 w, 414 w cm⁻¹. ESI+ MS: m/z 396 ([M +

(m, 4 H, PPh₂). ¹³C{¹H} NMR (CDCl₃): δ 59.47 (CH of fc), 64.42 H]⁺). Anal. Calc. for C₂₃H₁₈FeNP (395.2): C 69.90, H 4.59, N

(CH of fc), 71.57 (d, ³J_PC= 3 Hz, CH of fc), 73.78 (d, ²J_PC= 15 Hz, 3.54%. Found: C 69.79, H 4.63, N 3.35%.

CH of fc), 75.41 (d, J_PC= 4 Hz, C^ipso-P of fc), 106.05 (C^ipso-N of Synthesis of complex 6. A solution of

1

(20.0 mg, 50.6 µmol) in

1

fc), 128.13 (d, J_PC= 6 Hz, CH^metaof Ph), 128.46 (CH^paraof Ph), chloroform (1.5 mL) was added to a suspension of freshly

133.54 (d, ²J_PC= 19 Hz, CH^orthoof Ph), 139.47 (d, ¹J_PC= 9 Hz, C^ipsoprecipitated AgCl (7.3 mg, 50.6 µmol) in the same solvent (0.5

of Ph). ³¹P{¹H} NMR (CDCl₃): δ −16.7 (s). The NMR data are in mL) and the mixture was stirred in the dark for 24 h (a fine

3

accordance with the literature.¹⁹

yellow solid separated). The precipitated product was filtered

Synthesis of 5 from 2. Amine

2

(0.100 g, 0.26 mmol) was off, washed with chloroform and pentane, and dried under

dissolved in dry THF (5 mL) under an argon atmosphere. Neat vacuum. Yield of

formic acetic anhydride (31 µl, 0.39 mmol) was added to the solid. Note: An identical product was obtained when the

solution and the resulting mixture was stirred at room amount of was increased to 2 equiv. with respect to AgCl.

IR (Nujol): ν_max3114 w, 3081 w, 3052 w, 2160 s (N C), 2140

C), 1311 w, 1233 w, 1194 m, 1168 m, 1100 s, 1070 w,

6: 24.2 mg (89%), yellow virtually insoluble

1

temperature for 3 h. The reaction was terminated by addition

≡

of saturated aqueous NaHCO₃and diethyl ether (10 mL each; m (N

≡

an effervescence occurred). The aqueous layer was removed 1036 m, 1025 m, 910 m, 832 m, 824 m, 751 m, 741 vs, 696 vs,

and the organic one was washed with water and with brine, 631 w, 613 w, 594 w, 535 m, 515 s, 503 s, 489 s, 470 s, 459 m,

and dried over MgSO₄. Following evaporation under reduced 442 w, 427 m cm⁻¹. ESI+ MS: m/z 502 ([Ag( )]⁺), 704 ([Ag₂(

1 1)Cl₂

pressure, the crude product was purified by flash column + Na]⁺). Anal. Calc. for C₂₃H₁₈AgClFeNP·0.2CHCl₃(562.4): C

chromatography (silica gel, ethyl acetate-hexane 1:1) to afford 49.54, H 3.26, N 2.49%. Found: C 49.36, H 3.19, N 2.40%.

pure formamide

5

as an orange glassy solid (0.099 g, 93%).

Synthesis of complex 7. A solution of ligand 1 (20.0 mg, 50.6

Preparation of 1’-(diphenylphosphino)-1-isocyanoferrocene µmol) in acetone (1.5 mL) was added to a suspension of

(1). An oven-dried flask was charged with a stirring bar, amide Ag[SbF₆] (17.4 mg, 50.6 µmol) in the same solvent (0.5 mL) and

5

(413

mg,

1.0

mmol),

(benzotriazol-1- the mixture was stirred in the dark for 1 h (the solid silver(I)

yloxy)tris(dimethylamino)phosphonium hexafluorophosphate salt quickly dissolved). The resulting solution was filtered

(BOP; 884 mg, 2.0 mmol) and dry THF (20 mL) under argon. through a syringe filter (PTFE, 0.45 µm) and the filtrate was

Neat 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU; 0.38 ml, 2.5 crystallized by layering with acetone (1 mL) and then with

mmol) was added and the mixture was stirred at room hexane (10 mL) as a top layer. The crystals, which formed

temperature for 3 h (the partly soluble BOP dissolved during during standing in the dark for approximately one week, were

12 | J. Name., 2012, 00, 1-3

Please do not adjust margins

Dalton Transactions

Page 13 of 16

Journal Name

View Article Online

DOI: 10.1039/C7DT02336G

ARTICLE

isolated by suction, rinsed with pentane and dried under layered with chloroform (2 mL) and then with hexane (10 mL)

vacuum. Yield: 31.5 mg (84%), orange needle-like crystals. as a top layer and set aside for crystallization. The separated

¹H NMR (in situ, acetone-d₆): δ 4.26 (br s, 2 H, fc), 4.60 (br material was filtered off, washed with pentane and dried

s, 2 H, fc), 5.01 (vt, J′ = 1.7 Hz, 2 H, fc), 5.14 (br s, 2 H, fc), 7.54- under vacuum to afford 10 as an orange crystalline solid. Yield:

7.71 (m, 10 H, PPh₂). ³¹P{¹H} NMR (in situ, acetone-d₆): δ 6.8 40.6 mg (94%). Single crystals used for structure determination

1

(pair of d, J_AgP= 709 (¹⁰⁹Ag), 615 (¹⁰⁷Ag) Hz). IR (Nujol): ν_maxIR were obtained when the filtered solution was layered with

(Nujol): ν_max3119 w, 3050 w, 2210 m (N

C=O), 1316 w, 1230 m, 1198 w, 1173 m, 1101 m, 1059 w, 1034 product is practically insoluble.

m, 1001 w, 920 m, 848 w, 821 w, 750 s, 699 s, 664 vs, 653 vs, IR (Nujol): ν_max3128 w, 3082 w, 2223 s (N

542 w, 513 s, 472 m, 445 w, 430 m cm⁻¹. ESI+ MS: m/z 395 (1⁺), 1242 w, 1198 m, 1178 m, 1173 m, 1105 s, 1070 w, 1054 w,

502 ([Ag(

)]⁺), 646 ([Ag₂( ) + Cl]⁺), 897 ([Ag( )₂]⁺). Anal. Calc. 1036 m, 1030 m, 997 w, 925 m, 841 m, 822 s, 756 s, 747 s, 705

≡C), 1695 s (acetone, ethyl acetate and with hexane as a top layer. The crystalline

≡

C), 1311 m,

1

for C₂₃H₁₈AgF₆FeNPSb·(CH₃)₂CO (796.9): C 39.18, H 3.04, N s, 696 s, 635 w, 559 s, 534 s, 514 s, 495 s, 479 s, 470 m cm⁻¹.

1.76%; found C 39.49, H 3.07, N 1.72%.

ESI+ MS: m/z 824 ([M – Cl]⁺). Anal. Calc. for C₂₃H₁₈Au₂Cl₂FeNP

Preparation of complex 8. A solution of compound

1

(20.0 mg, (860.0): C 32.12, H 2.11, N 1.63%. Found: C 32.08, H 2.11, N

50.6 µmol) in acetone (1.5 mL) was added to Ag[SbF₆] in the 1.48%.

same solvent (8.7 mg, 25.3 µmol in 0.5 mL). After stirring in the Synthesis of complex 11a. A chloroform solution of isonitrile

1

dark for 90 min, the reaction mixture was filtered through a (20.0 mg, 50.6 µmol in 2 mL) was added to [Au(tht)₂][SbF₆]

PTFE syringe filter (0.45 µm pore size) and the filtrate was (30.8 mg, 50.6 μmol) dissolved in the same solvent (1 mL). The

carefully layered with acetone (1 mL) and, finally, with hexane resulting mixture was stirred for 60 min and then evaporated.

(10 mL) as the top layer. Crystallization by liquid-phase The residue was dissolved in acetone (2 mL) and the solution

diffusion (in the dark) provided crystals which were isolated by was crystallized by addition of hexane as the top layer (10 mL).

suction, washed with pentane and dried under vacuum. Yield The orange crystals, which separated during several days, were

of

8

: 20.1 mg (70%), orange needles.

filtered off, washed with pentane and dried under vacuum.

¹H NMR (in situ, acetone-d₆): δ 4.20 (br s, 2 H, fc), 4.71 (br Yield of 11a: 36.2 mg (79%).

s, 2 H, fc), 5.02 (br s, 2 H, fc), 5.10 (br s, 2 H, fc), 7.31-7.37 (m, 4

H, PPh₂), 7.42-7.50 (m, 6 H, PPh₂). ³¹P{¹H} NMR (in situ, vt, J = 3.1, 1.9 Hz, 2 H, fc), 5.16 (d vt, J = 1.2, 1.9 Hz, 2 H, fc),

1

acetone-d₆): δ –1.2 (br d, J_AgP= 207 Hz). IR (Nujol): ν_max3054 5.42 (vt, J

¹H NMR (acetone-d₆): δ 4.40 (vt, J

′ = 2.1 Hz, 2 H, fc), 4.74 (d

′

= 2.1 Hz, 2 H, fc), 7.65-7.71 (m, 4 H, PPh₂), 7.72-7.57

w, 2167 m (N

1098 s, 1030 s, 999 m, 917 s, 890 w, 829 s, 743 s, 696 s, 658 vs, d₆): δ 33.0 (s). IR (Nujol): ν_max3118 w, 3056 w, 2231 s (N

584 w, 519 m, 508 s, 494 s, 476 m, 464 m, 426 w cm⁻¹. ESI+ 1704 s, 1314 w, 1226 m, 1200 w, 1184 m, 1176 m, 1105 s,

MS: m/z 395 (

⁺), 897 ([Ag( )₂]⁺), 1688 ([Ag( )₄]⁺). Anal. Calc. 1060 w, 1034 m, 999 w, 921 w, 848 m, 834 m, 823 m, 755 s,

for C₄₆H₃₆AgF₆Fe₂N₂P₂Sb (1134.0): C 48.72, H 3.20, N 2.47%. 749 s, 715 w, 696 m, 660 vs, 553 m, 531 m, 519 s, 493 m, 476

Found: C 48.34, H 3.12, N 2.37%.

m, 435 w cm⁻¹. ESI+ MS: m/z 592 ([Au( )]⁺). Anal. Calc. for

Preparation of complex 9. [AuCl(tht]) (16.2 mg, 50.6 μmol) C₂₃H₁₈AuF₆FeNPSb (827.9): C 33.36, H 2.19, N 1.69%. Found: C

and compound (20.0 mg, 50.6 µmol) were reacted in 33.18, H 2.20, N 1.55%.

chloroform (1 + 2 mL) as described above and the reaction Preparation of complex 11b. A solution of ligand

≡

C), 1309 m, 1261 w, 1233 w, 1195 m, 1166 s, (m, 2 H, PPh₂), 7.80-7.87 (m, 4 H, PPh₂). ³¹P {¹H} NMR (acetone-

C),

≡

1

(20.0 mg,

mixture was filtered into pentane (30 mL). The precipitated 50.6 µmol) in dichloromethane (2 mL) was added to [AuCl(tht)]

solid was filtered off, washed with pentane and dried under (16.2 mg, 50.6 µmol) dissolved in the same solvent (1 mL).

vacuum. Yield of

for structure determination were grown from diethyl ether, 50.6 µmol) was added to the in situ formed

which slightly dissolves the product, layered with hexane. immediate separation of a white precipitate (AgCl). The

¹H NMR (acetone-d₆): δ 4.31 (vt, J

= 2.0 Hz, 2 H, fc), 4.63 (d mixture was stirred for another 30 min in the dark and then

vt, ³J_PH= 3.1 Hz, J

= 2.0 Hz, 2 H, fc), 4.73 (vt, J = 2.0 Hz, 2 H, fc), filtered through a syringe filter (0.45 µm PTFE). The filtrate was

4.88 (d vt, ⁴J_PH= 1.1 Hz, J

= 2.0 Hz, 2 H, fc), 7.57-7.74 (m, 10 H, evaporated to give an orange residue, which was taken up

PPh₂). ³¹P{¹H} NMR (acetone-d₆): δ 29.0 (s). IR (Nujol): ν_maxwith chloroform (1 mL). The solution was layered with

3087 w, 3052 w, 2220 w, 2125 s (N C), 1686 w, 1560 w, 1310 chloroform (1 mL) and then hexane (10 mL) as a top layer, and

9: 27.4 mg (87%), yellow solid. Crystals used After the mixture was stirred for 30 min, solid AgNTf₂(19.6 mg,

9

, causing

′

≡

m, 1231 w, 1198 w, 1176 m, 1102 s, 1070 w, 1028 s, 998 m, allowed to crystallize by liquid-phase diffusion over several

919 m, 893 w, 834 m, 823 m, 758 s, 743 s, 694 s, 637 w, 558 s, days. The orange crystals that formed were isolated by suction

532 s, 514 s, 494 m, 482 s, 453 w, 436 w cm⁻¹. ESI+ MS: m/z and dried under vacuum. Yield: 40.8 mg (92%).

592 ([M − Cl]⁺). Anal. Calc. for C₂₃H₁₈AuClFeNP (627.6): C 44.01,

¹H NMR (CDCl₃): δ 4.01 (vt, J

= 3.2 Hz, 2.0 Hz, 2 H, fc), 4.97 (v dt, J

= 2.0 Hz, 2 H, fc), 7.52-7.60 (m, 6 H, PPh₂), 7.63-7.70

101 µmol) in chloroform (2 mL) was mixed with a solution of (m, 4 H, PPh₂). ³¹P{¹H} NMR (CDCl₃): δ 32.1 (s). ¹⁹F NMR

ligand in the same solvent (20.0 mg, 50.6 µmol in 2 mL). (CDCl₃): δ –78.6 (s). IR (Nujol): ν_max3113 m, 3056 m, 2233 m

After stirring for 1 h, the mixture was concentrated under (N C), 1351 s, 1227 s, 1193 s, 1134 s, 1104 m, 1056 s, 999 w,

′

= 2.0 Hz, 2 H, fc), 4.76 (v dt, J

′

H 2.89, N 2.23%. Found: C 43.76, H 2.96, N 1.99 %.

′

= 1.9 Hz, 1.2 Hz, 2 H, fc),

Preparation of complex 10. A solution of [AuCl(tht)] (32.5 mg, 5.12 (vt, J

′

1

≡

reduced pressure (to approximately half the volume) and 922 w, 828 w, 788 m, 748 m, 694 m, 652 m, 615 m, 600 m, 570

filtered through a syringe filter (0.45 µm PTFE). The filtrate was m, 555 w, 530 m, 517 s, 476 m, 435 w cm⁻¹. ESI+ MS: m/z 592

J. Name., 2013, 00, 1-3 | 13

Please do not adjust margins

Dalton Transactions

Page 14 of 16

View Article Online

DOI: 10.1039/C7DT02336G

ARTICLE

)]⁺). Anal. Calc. for C₂₅H₁₈AuF₆FeN₂O₄PS₂(871.9): C 34.42,

Journal Name

([Au(

1

H 2.08, N 3.21%. Found: C 34.33, H 2.29, N 3.18%.

3

a) Ferrocenes: Ligands, Materials and Biomolecules, ed. P.

Štěpnička; Wiley, Chichester, 2008; b) Ferrocenes:

Homogeneous Catalysis, Organic Synthesis, Materials

Science, ed. A. Togni, T. Hayashi, VCH, Weinheim 1995.

T. El-Shihi, F. Siglmüller, R. Herrmann, M. F. N. N. Carvalho

and A. J. L. Pombeiro, J. Organomet. Chem., 1987, 335, 239.

Catalytic experiments. A reaction flask was charged with

alcohol 12 (1.0 mmol; ca. 90:10 mixture of (Z)- and (E)-isomers,

the (E)-isomer does not cyclize), 1,2-dichloroethane (1.0 mmol;

internal standard) and CDCl₃(2 or 4 mL). The catalyst was

added and the resulting mixture was stirred in the dark for a

given reaction time and then analyzed by ¹H NMR

spectroscopy to determine the conversion.

4

5

For an alternative synthesis of

Pauson, D. Willison, E. Solčániová and Š. Toma,

Organometallics, 1990, , 301.

A, see: G. R. Knox, P. L.

9

6

Note that aminoferrocene, an obvious synthetic precursor to

isocyanoferrocene, was prepared already in 1955 (ref 6a),

while cyanoferrocene was reported only two years later

(refs. 6b-d): a) F. S. Arimoto and A. C. Haven, Jr., J. Am.

Chem. Soc., 1955, 77, 6295; b) G. D. Broadhead, J. M.

Osgerby and. P. L. Pauson, Chem. Ind., 1957, 209 (Chem.

Abstr. 1957, 62321); c) G. D. Broadhead, J. M. Osgerby and.

P. L. Pauson, J. Chem. Soc. 1958, 650; d) P. J. Graham, R. V.

Lindsey, G. W.; Parshall, M. L.; Peterson and G. M. Whitman,

J. Am. Chem. Soc., 1957, 79, 3416.

a) M. V. Barybin, T. C. Holovics, S. F. Deplazes, G. H.

Lushington, D. R. Powell and M. Toriyama, J. Am. Chem. Soc.,

2002, 124, 13668; b) T. C. Holovics, S. F. Deplazes, M.

Toriyama, D. R. Powell, G. H. Lushington and M. V. Barybin,

Organometallics, 2004, 23, 2927; c) P. J. Shapiro, R. Zehnder,

D. M. Foo, P. Perrotin, P. H. M. Budzelaar, S. Leitch and B.

Twamley, Organometallics, 2006, 25, 719; d) V. N. Nemykin,

A. A. Purchel, A. D. Spaeth and M. V. Barybin, Inorg. Chem.,

2013, 52, 11004; e) V. N. Nemykin, S. V. Dudkin, M. Fathi-

Rasekh, A. D. Spaeth, H. M. Rhoda, R. V. Belosludov and M.

V. Barybin, Inorg. Chem., 2015, 54, 10711.

X-ray crystallography. The diffraction data (completeness

≥

99%, θ_max= 27.5°) were collected at 150(2) K using either

Nonius KappaCCD diffractometer with a Bruker Apex-II image

plate detector or

PHOTON100 instrument with a IµS micro-focus X-ray tube,

both equipped with Cryostream Cooler (Oxford

Cryosystems). Mo K radiation was used throughout.

a Bruker D8 VENTURE Kappa Duo

a

α

The structures were solved by direct methods (SHELXS-97)

and refined by a full-matrix least squares procedure based on

F²using SHELXL-97.⁵¹The non-hydrogen atoms were refined

with anisotropic thermal motion parameters. The NH

7

hydrogen atoms in the structure of

2 and 5 were located on

the difference Fourier maps, and their positions were freely

refined with U_iso(H) set to 1.2 U_eq(N). All other hydrogen atoms

were included in their calculated positions and refined using

the “riding model”.

Selected crystallographic data, data collection and

structure refinement parameters are presented in the ESI

(Table S1). All geometric calculations were performed with a

recent version of the PLATON program,⁵²which was also used

to prepare the structural diagrams.

8

9

D. van Leusen and B. Hessen, Organometallics, 2001, 20,

224.

a) U. Siemeling, D. Rother, C. Bruhn, H. Fink, T. Weidner, F.

Träger, A. Rothenberger, D. Fenske, A. Priebe, J. Maurer and

R. Winter, J. Am. Chem. Soc., 2005, 127, 1102; b) T. Weidner,

N. Ballav, M. Zharnikov, A. Priebe, N. J. Long, J. Maurer, R.

Winter, A. Rothenberger, D. Fenske, D. Rother, C. Bruhn, H.

Fink and U. Siemeling, Chem. Eur. J., 2008, 14, 4346; c) U.

Siemeling, L. R. R. Klapp and C. Bruhn, Z. Anorg. Allg. Chem.,

2010, 636, 539.

DFT computations. DFT calculations were performed using the

PBE0 density functional⁵³combined with the SDD (Fe, Au) and

cc-pVDZ (C, H, N, and P) basis sets. The solvent effects (CHCl₃)

have been approximated by the polarized continuum model

(PCM)⁵⁴as implemented in the Gaussian 09 program

package.⁵⁵The geometry optimizations were started from the

10 A few more isocyanides bearing ferrocenyl substituents at

the organic backbone were mentioned in ref. 4.

coordinates determined by X-ray diffraction analysis. The 11 D. M. McGinnis, S. F. Deplazes and M. V. Barybin, J.

Organomet. Chem., 2011, 696, 3939.

reported energies refer to the Gibbs free energies at 298 K.

Computed energies and coordinates are presented in the ESI

(Table S2 and mol2 files).

12 a) K. Škoch, I. Císařová and P. Štěpnička, Inorg. Chem., 2014,

53, 568; b) K. Škoch, I. Císařová and P. Štěpnička, Chem. Eur.

J., 2015, 21, 15998; c) K. Škoch, F. Uhlík, I. Císařová and P.

Štěpnička, Dalton Trans. 2016, 45, 10655.

13 a) K.-S. Gan and T. S. A. Hor in Ferrocenes: Homogeneous

Catalysis, Organic Synthesis, Materials Science, ed. A. Togni

and T. Hayashi; Wiley-VCH: Weinheim, 1995, ch. 1, p. 3 ff.; b)

S. W. Chien and T. S. A. Hor in Ferrocenes: Ligands, Materials

and Biomolecules, ed. P. Štěpnička; Wiley, Chichester, 2008;

ch. 2, p. 33 ff.; c) G. Bandoli and A. Dolmella, Coord. Chem.

Rev., 2000, 209, 161; d) D. J. Young, S. W. Chien and T. S. A.

Hor, Dalton Trans., 2012, 41, 12655.

14 a) R. B. King and A. Efraty, J. Am. Chem. Soc., 1971, 93, 564;

b) R. B. King and A. Efraty, J. Chem. Soc.; Chem. Commun.,

1974, 1371.

15 a) C.-Y. Liu, D.-Y. Chen, M.-C. Cheng, S.-M. Peng and S.-T. Liu,

Organometallics, 1995, 14, 1983; b) I. Yu, C. J. Wallis, B. O.

Patrick, P. L. Diaconescu and P. Mehrkhodavandi,

Organometallics, 2010, 29, 6065.

Acknowledgements

The research reported in this paper received support from the

Czech Science Foundation (project no. 17-02495S).

References

1

a) Isocyanide Chemistry: Applications in Synthesis and

Material Science, ed. V. G. Nenajdenko; Wiley-VCH,

Weinheim, 2012; b) A. Dömling, Chem. Rev., 2006, 106, 17; c)

G. Qiu, Q. Ding and J. Wu., Chem. Soc. Rev., 2013, 42, 5257;

d) V. P. Boyarskiy, N. A. Bokach, K. V. Luzyanin and V. Y.

Kukushkin, Chem. Rev., 2015, 115, 2698.

16 L. Zhang, W. Yu, C. Liu, Y. Xu, Z. Duan and F. Mathey,

Organometallics, 2015, 34, 5697.

17 Isonitrile Chemistry, ed. I. Ugi; Academic Press, New York,

2

a) Y. Yamamoto, Coord. Chem. Rev., 1980, 32, 193; b) E.

Singleton and H. E. Oosthuizen, Adv. Organomet. Chem.,

1983, 22, 209.

1971

.

14 | J. Name., 2012, 00, 1-3

Please do not adjust margins

Dalton Transactions

Page 15 of 16

Journal Name

View Article Online

DOI: 10.1039/C7DT02336G

ARTICLE

18 P. Štěpnička in Ferrocenes: Ligands, Materials and 43 a) H. Schmidbaur, Chem. Soc. Rev., 1995, 391; b) H.

Schmidbaur, Gold. Bull., 2000, 33, 3; c) H. Schmidbaur and A.

Schier, Chem. Soc. Rev., 2012, 41, 370

Biomolecules, ed. P. Štěpnička; Wiley, Chichester, 2008; ch.

5, p. 177 ff.

19 I. R. Butler and S. C. Quayle, J. Organomet. Chem., 1998, 552

63.

20 The reaction mixture resulting after addition of O-

benzylhydroxylamine to in situ generated Ph₂PfcLi contained

mostly (diphenylphosphino)ferrocene, uncreacted amination

reagent and only traces of amine 2.

21 Similar problems were noted before: a) M. Ritte, C. Bruhn

and U. Siemeling, Z. Naturforsch., 2014, 69b, 906. See also:

,

44 C. Hansch, A. Leo and R. W. Taft, Chem. Rev., 1991, 91, 165.

45 Our observations are in agreement with the theoretical

computations on the series of cations [(η⁵-C₅H₅)₃ML]⁺, where

L is MeC≡N or MeN≡C, and M = Ti, Zr or Hf, revealing that

the isontrile consistently forms stronger coordination bonds

to the metal centre: H. Jacobsen, H. Berke, T. Brackemeyer,

T. Eisenblätter, G. Erker, R. Fröhlich, O. Meyer and K.

Bergander, Helv. Chim. Acta, 1998, 81, 1692.

b) S. Dey, J. W. Quail and J. Müller, Organometallics, 2015, 46 P. Štěpnička, J. Schulz and I. Císařová, Acta Crystallogr., Sect.

34, 3039. E, Struct. Rep. Online, 2009, 65, m1210.

22 A. Leonidova, T. Joshi, D. Nipkow, A. Frei, J.-E. Penner, S. 47 D. P. Day, T. Dann, R. J. Blagg and G. G. Wildgoose, J.

Konatschnig, M. Patra and G. Gasser, Organometallics, 2013,

32, 2037 and references cited therein.

23 We have noted that desulfuration of ferrocene P-sulfides by

Organomet. Chem., 2014, 770, 29.

48 L. I. Krimen, J. Savage and P. Yates, Org. Synth., Coll. Vol. 6,

1988, 8 (accessed online at doi: 10.15227/orgsyn.050.0001).

Raney nickel can be accompanied by removal of the entire 49 R. Uson, A. Laguna and M. Laguna, Inorg. Synth., 1989, 26

phosphine substituent already before: P. Štěpnička, B. 85.

Schneiderová, J. Schulz and I. Císařová. Organometallics, 50 F. Barrière and W. E. Geiger, J. Am. Chem. Soc., 2006, 128

2013, 32, 5754. 3980.

24 I. Ugi, U. Fetzer, U. Eholzer, H. Knupfer and K. Offermann, 51 G. M. Sheldrick, Acta Crystallogr., Sect. A: Found. Crystallogr.,

Angew. Chem. Int. Ed. 1965, , 472. 2008, 64, 112.

25 The dehydration of oximes to nitriles with BOP/DBU was 52 A. L. Spek, Acta Crystallogr, Sect. D: Biol. Crystallogr., 2009,

,

4

reported in: M. K. Singh and M. K. Lakshman, J. Org. Chem.

2009, 74, 3079.

26 M.K. Das and S. Roy, Synth. React. Inorg. Met.-Org. Chem., 54 a) J. Tomasi, B. Mennucci and R. Cammi, Chem. Rev., 2005,

65, 148.

53 C. Adamo and V. Barone, J. Chem. Phys., 1999, 110, 6158.

1986, 16, 67.

27 K. BongSoo, J. M. Beebe, Y. Jun, X.-Y. Zhu and C. D. Frisbie, J.

Am. Chem. Soc., 2006, 128, 4970.

105, 2999; b) G. Scalmani and M. J. Frisch, J. Chem. Phys.,

2010, 132, 114110.

55 M. J. Frisch, et al. Gaussian 09, Revision A.02; Gaussian, Inc.:

28 P. Walla, V. B. Arion and U. H. Brinker, J. Org. Chem., 2006,

71, 3274.

Wallingford, CT, 2009.

29 A. Shafir, M. P. Power, G. D. Whitener and J. Arnold,

Organometallics, 2000, 19, 3978.

30 M. J. Verschoor-Kirss, O. Hendricks, C. M. Verschoor, R.

Conry and R. U. Kirss, Inorg. Chim. Acta, 2016, 450, 30.

31 Z.-G. Fang, T. S. A. Hor, Y.-S. Wen, L.-K. Liu and T. C. W. Mak,

Polyhedron, 1995, 14, 2403.

32 K. J. Donaghy, P. J. Carroll and L. G. Sneddon, Inorg. Chem.,

1997, 36, 547.

33 B. Wrackmeyer, H. E. Maisel, O. L. Tok, W. Milius and M.

Herberhold, Z. Anorg. Allg. Chem., 2004, 630, 2106.

34 K. Heinze and M. Schlenker, Eur. J. Inorg. Chem., 2004, 2974.

35 A. Cassel, Acta Crystallogr., Sect B: Struct. Crystallogr. Cryst.

Chem., 1979, 35, 174.

36 K. Yang, S. G. Bott and M. G. Richmond, J. Chem. Crystallogr.,

1995, 25, 263.

37 M. M. Olmstead, M. Sheffrin and F. Jiang, Acta Crystallogr.,

Sect E: Struct. Rep. Online, 2004, 60, m1142.

38 B. Cordero, V. Gómez, A. E. Platero-Prats, M. Revés, J.

Echeverría, E. Cremades, F. Barragán and S. Alvarez, Dalton

Trans., 2008, 2832.

39 A search in Cambridge Crystallographic Database (version

5.38 of November 2016 with updates from November 2016

and February 2017) for Ag-C≡N-C fragments resulted in 63

hits and 129 Ag-C distances. Average value: 2.14(8) Å,

median: 2.11 Å.

40 Spectral Database for Organic Compounds (SDBS): IR

spectrum

of

neat

acetone;

SDBS

No.:

319;

http://riodb01.ibase.aist.go.jp/sdbs/ (accessed April 21,

1

2017); ν .

_C=O: 1715 cm⁻

41 The broadening can be tentatively ascribed to

molecular dynamics of the sterically crowded complex cation

in

. The ¹H NMR signals also display broad resonances.

a slow

8

42 O. Crespo, M. C. Gimeno, P. G. Jones and A. Laguna, Acta

Crystallogr., Sect. C: Struct. Chem., 2000, 56, 1433.

J. Name., 2013, 00, 1-3 | 15

Please do not adjust margins

Dalton Transactions

Page 16 of 16

View Article Online

DOI: 10.1039/C7DT02336G

Graphical Abstract

1’-(Diphenylphosphino)-1-isocyanoferrocene (1) was

synthesized and studied as a hybrid ligand in Ag(I)

and Au(I) complexes; the catalytic activity of the

Au(I) complexes was evaluated.

Article Doi

Synthesis and characterization of 1′-(diphenylphosphino)-1-isocyanoferrocene, an organometallic ligand combining two different soft donor moieties, and its Group 11 metal complexes

DOI: 10.1039/c7dt02336g

Source and publish data:

Authors:

Article abstract of DOI:10.1039/c7dt02336g

Full text of DOI:10.1039/c7dt02336g

Products guided by the article

R&D Labs maybe for 14920-89-9

Relevant to this article

Hot Product