Calcium complexes with imino-phosphinanilido chalcogenide ligands for heterofunctionalisation catalysis

Article abstract of DOI:10.1039/c6ra13117d

The syntheses, characterisation and utilisation of the calcium complexes [{L^x}CaN(SiMe₃)₂·(THF)] supported by monoanionic, tridentate imino-phosphinanilido chalcogenide ligands {Ph₂P(E)-N-C₆H₄

Full text of DOI:10.1039/c6ra13117d

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ARTICLE TYPE
Calcium Complexes with Imino-phosphinanilido Chalcogenide Ligands for
Heterofunctionalisation Catalysis
‡
§
‡
§
§
Srinivas Anga, JeanꢀFrançois Carpentier,* Tarun K. Panda,* Thierry Roisnel, and Yann Sarazin*
Received (in XXX, XXX) Xth XXXXXXXXX 20XX, Accepted Xth XXXXXXXXX 20XX
DOI: 10.1039/b000000x
5
x
The syntheses, characterisation and utilisation of the calcium complexes [{L }CaN(SiMe ) ꢁ(THF)] supported by monoanionic, tridentate
3
2
–
2
–
3 –
iminoꢀphosphinanilido chalcogenide ligands {Ph P(E)ꢀNꢀC H ꢀCH=N(Dipp)} (E = S, {L } ; E = Se, {L } ; Dipp = 2,6ꢀ
diisopropylphenyl) as molecular precatalysts for the heterofunctionalisation of styrene are reported. The protioꢀligand {L }H (for E = O)
2
6
4
1
0
1
0
was obtained upon reaction of the anilineꢀiminophosphane {Ph PHNꢀC H ꢀCH=N(Dipp)} ({L }H) and hydrogen peroxide at room
2
6
4
2
3
0
temperature. The related sulphide and selenide compounds {L }H and {L }H were prepared by treatment of {L }H with elemental
0
sulphur and selenium. Beside, reaction of {L }H with Me S.BH yielded the corresponding iminoꢀphosphinanilido borane protioꢀligand
Ph P(BH )NꢀC H ꢀCH=N(Dipp)}H ({L }H). The heteroleptic calcium complexes [{L }CaN(SiMe ) ꢁ(THF)] (E = S, 2; E = Se, 3) were
2 3 6 4 3 2
synthesised by oneꢀpot reaction of {L }H and {L }H with 2 equiv of [KN(SiMe ) ] and CaI at room temperature. The reaction of {L }H
with [KN(SiMe ) ] and CaI in 2:2:1 proportions yielded the homoleptic complex [Ca{L } ] (5). The molecular structures of the protioꢀ
3 2 2 2
ligand {L }H and complexes 3 and 5 were established by single crystal Xꢀray analysis. The heteroleptic complexes 2 and 3 constitute
moderately efficient precatalysts for the intermolecular hydrophosphination and hydroamination of styrene with diphenylphosphine or
pyrrolidine, respectively, to mediate the formation of C–P and C–N σꢀbonds.
2
3
4
x
{
2
3
2
3
2
2
2
1
5
3
Introduction
45 complexes and tame their propensity to engage in deleterious
ligand redistribution (Schlenkꢀlike) equilibria.
6ꢀ10
2
0
The catalytic activity of these precatalysts built around large,
electropositive Ae ions compares well with that of isoelectronic
trivalent lanthanide systems. The calcium complex
Catalysed heterofunctionalisations of unsaturated substrates
(
alkenes, carbonyls) continue to receive significant attention,
1
primarily because of their 100% atom efficiency. Alkene
hydroamination (C–N σꢀbond formation) and hydrophosphination
(C–P σꢀbond formation) have attracted a great deal of attention in
recent years, not least because the resulting amines and
phosphines constitute valuable products for a plethora of
50
[{BDI}CaN(SiMe ) ꢁ(THF)] ({BDI}
=
HC{C(Me)N–2,6–
3
2
i
(
Pr) C H } ) proved a very versatile and effective precatalyst not
2
6
3 2
2
3
3
5
0
5
only for intramolecular hydroaminations, but also for the more
challenging intermolecular hydrophosphination of alkynes and
6,11
activated alkenes.
Several other heteroleptic calcium,
applications. Substantial advances were achieved for 55 strontium and barium complexes supported by a related
intramolecular hydroamination in the 90’s with alkali or
iminoanilido or aminoetherphenolato ligands have also been
reported for the intermolecular hydroamination and
hydrophosphination of activated alkenes.
2
ꢀ3
transition metal complexes. Most prominently for oxophilic
metals, Mark’s lanthanide(III) catalysts are remarkable for their
8
4
efficiency in the cyclisation of aminoalkenes, aminoalkynes and
In the course of our ongoing research into the chemistry of heavy
5
in the cyclohydrophosphination of phosphinoalkenes. More 60 alkaline earths, we have recently introduced a series of
recently, the cyclohydroamination of aminoalkenes was catalysed
amidophosphineꢀchalcogenides/boranes [R NHPh P(E)] (R =
2 2 n
0
by d complexes of the alkalinoꢀearth metals (Ae) as shown by
bulky alkyl; E = O, S, Se, BH ; n = 1 or 2) and sterically
3
6
7
8
9
Hill, Roesky, Sarazin/Carpentier and Ward. These groups have
demanding nitrogen ancillary ligands [2ꢀ(Ph CN=CH)C H NH]
3
4
3
1
2
developed various original heteroleptic Ae complexes of the type
into alkali and alkalinoꢀearth metal coordination chemistry. In
–
[
{L}Ae(X)(solvent) ], where Ae is Ca, Sr or Ba, {L} is a 65 all cases, the ligand with multiple donor atoms stabilised the
n
monoanionic ancillary ligand such as a
phosphinomethanide, bis(imino)pyrrolide, aminotroponiminate,
tris(pyrazolyl)borate, iminoanilide or aminoetherphenolate, and
β
ꢀdiketiminate, bisꢀ
oxophilic ions, and the molecular structures of the resulting
complexes were authenticated. The Ae compounds showed
excellent catalytic activity towards the ringꢀopening
polymerisation of εꢀcaprolactone. However, the major
4
0
–
–
X
is a reactive group such as an amide (e.g. N(SiMe ) or
3
–
–
N(SiMe H) ) or, sometimes, an alkyl (CH(SiMe ) ). The bulky 70 disadvantage of these ligands was their relatively limited ability
2
3 2
ancillary ligand is essential to control the kinetic lability of these
to prevent ligand redistribution in solution. Thus, we were led to
conclude that greater steric bulkiness might be necessary to
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2
3
prevent these deleterious equilibria from taking place. To
circumvent this problem, sterically more demanding multidentate
monoanionic ligands were devised for the kinetic stabilisation of
corresponding sulphide {L }H and selenide {L }H congeners in
4
yields above 85% (Scheme 1). The borane adduct {L }H was
isolated in quantitative yield as yellow precipitate by the reaction
heteroleptic Ae complexes. We report here the syntheses of 40 of {L }H and Me S.BH in toluene (Scheme 1). These protioꢀ
0
2
3
5
iminoꢀphosphinanilido
CH=N(Dipp)}H (E = O, {L }H; S, {L }H; Se, {L }H; Dipp =
chalcogenides
{Ph P(E)ꢀNꢀC H ꢀ
ligands were characterised by multinuclear NMR and combustion
2
6
4
1
2
3
1
analysis. In the H NMR spectra, the amine NH hydrogen atom
2
2
,6ꢀdiisopropylphenyl)
and
iminoꢀphosphinanilidoborane
can be seen at δ1Η = 11.41ꢀ11.44 ppm as a doublet with J
HP
4
1
2
{
Ph P(BH )NꢀC H ꢀCH=N(Dipp)}H ({L }H)) along with the
coupling constants of 13.7 for {L }H, 10.2 for {L }H, and 9.0 Hz
2
3
6
4
3
4
syntheses and structural aspects of the calcium complexes 45 for {L }H. In {L }H, its resonance is seen at δ = 11.19 ppm,
1
Η
x
2
1
1
2
0
[{L }CaN(SiMe ) ꢁ(THF)] (E = S, x = 2, 2; E = Se, x = 3, 3) and
[
3 2
with JHP = 4.0 Hz. In all cases, there is hence a significant
downfield shift as compared with {L }H. In their P{ H} NMR
2
0
31
1
Ca{L } ] (5). The ability of 2 and 3 to catalyse the
2
2
3
intermolecular hydrophosphination and hydroamination of
styrene is also presented.
spectra, {L }H and {L }H exhibit similar resonances at δ
=
1P
3
4
9.8 and 45.0 ppm, respectively. This is shifted downfield
1
50
compared to the data for {L }H (δ3 = 19.0 ppm), presumably
1P
due to the adjacent hard oxygen atom. However, the borane
5
Results and discussion
4
derivative {L }H displays an even more downfield broad
Synthesis and characterisation: The phosphinanilidoꢀimine
1
1
1
0
resonance signal at δ31P = 65.8 ppm. Additionally, in the B{ H}
NMR spectrum, a broad resonance signal at δ11Β = –36.0 ppm
precursor {Ph PHNꢀC H ꢀCH=N(Dipp)} ({L }H) was readily
2
6
4
obtained in good yield and high purity by equimolar aminolysis
of chlorodiphenylphosphine with {H NC H CH=N(Dipp)} in
toluene at room temperature, using a slight excess of
55
was detected for the P–BH moiety. These observations indicate
3
2
6
4
that the BH group formed the phosphineꢀborane adduct rather
3
0
3
than the amineꢀborane one. The seleniumꢀcontaining {L }H was
characterised by Se{ H} NMR spectroscopy; it features a
triethylamine to trap the released HCl (Scheme 1).
77
1
1
doublet at δ77Se = –251 ppm, with J coupling constant of 776
SeP
60
Hz (Figure 1) which matches that measured in this compound’s
P{ H} NMR spectrum (Fig. 1).
31
1
7
7
1
Figure 1. Se{ H} NMR (CDCl , 76.31 MHz, 25 ºC) (top right)
3
31
1
65
and P{ H} NMR (CDCl , 161.9 MHz, 25 ºC) spectra for
Ph P(Se)ꢀNꢀC H ꢀCH=N(Dipp)}H ({L }H).
3
3
Scheme 1. Synthesis of iminoꢀphosphinanilido chalcogenides and
{
2
6
4
x
25
30
35
borane protioꢀligands {L }H, x = 1−4.
3
The solid state structure of {L }H was established by single
crystal Xꢀray diffraction. Its molecular structure is depicted in
0
The precursor {L }H was characterised by conventional
techniques. In the H NMR spectrum, the signal for the amine 70 Fig. 2. The P–Se bond distance of 2.0930(7) Å is very similar to
NH hydrogen atom appears at δ1Η = 10.28 ppm as a doublet due
to coupling with the phosphorus atom ( J of 9.1 Hz). The
1
1
3
that previously reported for [Ph P(Se)ꢀNH(2,6ꢀMe C H )]
2 2 6 3
(2.1019(8) Å) and is hence diagnostic of P=Se double bonds. The
P–N bond distance of 1.662(2) Å is consistent with those
2
HP
resonance for the imine proton appears as a singlet at δ = 8.27
ppm. In the P NMR spectrum, the compound exhibits a sharp
1Η
3
1
12,13
measured in other phosphinamines.
singlet at δ31P = 23.3 ppm.
The oxide ligand {L }H was prepared in 85% yield by treatment
of {L }H with hydrogen peroxide, whereas the action of
elemental sulphur and selenium onto {L }H afforded the
75
1
0
0
2
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spectra recorded in C D , the resonance for the imine proton
6
6
40
appears at δ1Η = 7.91 and 7.92 ppm for complexes 2 and 3
respectively, i.e. slightly shifted towards high fields with respect
to the protioꢀligands (δ1Η = 8.26 and 8.27 ppm); the presence of
one molecule of coordinated THF per metal is unambiguous. In
31
1
the P{ H} NMR spectra, sharp resonances were detected at δ
3
1P
45
= 40.6 (for 2) and 31.1 ppm (for 3, Fig. 3), i.e. at higher field than
in the respective protioꢀligands. In the Se{ H} NMR spectra of
77
1
3
(Fig. 3), a doublet was observed at δ7 = –61 ppm, with a
7Se
1
coupling constant J of 589 Hz. The substantial lowꢀfield shift
SeP
and the lower coupling constant compared to the pertaining data
3
50
for {L }H are indicative of coordination of the selenium atom
Figure 2. Molecular solidꢀstate structure of {Ph P(Se)ꢀNꢀC H ꢀ
2
6
4
3
onto the calcium ion in 3.
CH=N(Dipp)}H ({L }H). Hydrogen atoms except that on N1 are
omitted for clarity. Selected bond lengths (Å) and angles (°):
Se1–P1 2.0933(7), P1–N1 1.662(2), N2–C7 1.264(3), N1–C1
5
1
.384(3), N1–P1–Se1 117.11(9), C1–N1–P1 129.59(2), N1–C1–
C6 119.1(2), C7–N2–C8 119.8(2).
8
2
Using a known strategy, the oneꢀpot reaction of {L }H with
[KN(SiMe ) ] in THF followed by the addition of CaI (in 1:2:1
1
1
2
2
3
0
5
0
5
0
3
2
2
molar ratio) cleanly yielded the desired heteroleptic complex
2
[
{L }CaN(SiMe ) ꢁ(THF)] (2) in 75% yield. The analogous
3 2
3
reaction with the selenide {L }H afforded analytically pure
[
3
{L }CaN(SiMe ) ꢁ(THF)] (3) in 71% yield (Scheme 2).
3 2
However, all attempts to prepare the congeneric complex
1
[
{
{L }CaN(SiMe ) ꢁ(THF)] (1) using the oxygenꢀcontaining
3 2
1
L }H proved unsuccessful and gave intractable mixtures of
unidentified species, presumably because of issues stemming
from the combined presence of the phosphine oxide with
oxophilic element such as calcium. Note also that, similarly, the
7
7
1
Figure 3. Se{ H} NMR (C D , 76.31 MHz, 25 ºC (top right)
6
6
31
1
5
5
and P{ H} NMR (C D , 161.9 MHz, 25 ºC) spectra for
{L }CaN(SiMe ) ꢁ(THF)] (3).
3 2
4
6 6
use of the borane ligand {L }H afforded a complex with the
3
[
4
putative formulation [{L }CaN(SiMe ) ·(THF)] (4), but NMR
3
2
data were inconclusive and the composition could not be
confirmed by elemental analysis either. Nonetheless, analysis of a
small crop of single crystals by XRD techniques confirmed the
proposed formulation, and showed coordination of two of the
three hydrogen atoms in the borane moiety onto the calcium
center; a representation of the molecular structure and the XRD
data for 4 is available in the electronic supporting information.
Xꢀray quality crystals of complex 3 were grown at –30 ºC from a
concentrated pentane solution, and its structure was determined
3
60
(Fig. 4). The
κ
ꢀcoordination mode of the ligand is plain in the
structure of 3, and the corresponding metric parameters are
diagnostic. The additional presence of coordinated THF takes the
formal coordination number around Ca to five.
Scheme 2. Synthesis of the heteroleptic calcium complexes
65
2
3
3
[
{L }CaN(SiMe ) ꢁ(THF)] (2) and [{L }CaN(SiMe ) ꢁ(THF)] (3).
Figure 4. Solidꢀstate structure of [{L }CaN(SiMe
3
)
2
·(THF)] (3).
3
2
3 2
All hydrogen atoms are omitted for clarity. Selected bond lengths
Å) and angles (°): Ca1−N1 2.395(5), Ca1−N41 2.369(4),
Ca1−N21 2.502(5), Ca1−Se1 3.016(2), Ca1−O11 2.387(4),
3
5
(
Complexes 2 and 3 were characterised by multinuclear NMR
spectroscopy and elemental analysis, and the solidꢀstate structure
1
of 3 was confirmed by Xꢀray diffraction analysis. In the H NMR 70 Ca1−P1 3.240(2), Se1−P1 2.152(1), N41−P1 1.616(4), N21−C34
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1
.276(7), N1−Ca1−O11 100.26(2), N1−Ca1−N41 112.92(2),
recorded in C D . A singlet resonance at δ = 7.88 ppm was
6 6 1H
O11−Ca1−N41
O11−Ca1−N21
N41−Ca1−Se1
146.61(1),
89.09(1),
120.66(1),
N1−Ca1−N21
N41−Ca1−N21
O11−Ca1−Se1
129.02(2),
73.23(1), 50 groups in the ligand gave rise to a septet at δ1H = 2.89 ppm for
93.43(1),
CH(CH hydrogen atoms and a broad doublet centred on 1.07
observed for the two imine (N=CH) protons. The 2,6ꢀdiisopropyl
)
3 2
31
ppm for the methyl moieties. In the P NMR spectrum, a singlet
5
N41−Ca1−Se1 67.01(1), N21−Ca1−Se1 108.44(1), N1−Ca1−P1
13.94(1), O11−Ca1−P1 131.62(1), N41−Ca1−P1 28.64(1),
at δ31P = 62.6 ppm was observed, i.e. at much lower field than in
1
2
or in the protioꢀligand.
N21−Ca1−P1 94.33(1), Se1−Ca1−P1 40.04(3).
55
The arrangement around the calcium ion is intermediate between
a square base pyramidal and trigonal bipyramidal. However, with
10
15
20
1
4
a geometric parameter of τ = 0.63, the geometry around the
5
metal ion can be best described as a highly distorted trigonal
bipyramidal with N1, N21 and Se1 sitting in equatorial positions
and O1 and N41 in axial ones. The dihedral angle of 53.2 °
between the two planes defined by N21, Ca1, N41, C34 and Ca1,
Se1, P1, N1 indicates that the two metallacycles are not coplanar.
The distance from Ca1 to the imine N2 atom (2.502(5) Å) is
greater than that to the amido N1 (2.329(5) Å) and N3 (2.396(4)
Å) atoms; the discrepancy between the Ca1−N1 and Ca1−N3
bond lengths reflects the formation of the Ca1−N1−P1−Se1
metallacycle, and the bulkiness of the hexamethyldisilazide
group. The Ca1−Se1 distance of 3.0164(16) Å compares with
1
2a
those in [Ca{Ph P(Se)N(CHPh )} ·(THF) ] (2.989(8) Å) and
2
2
2
2
Figure 5. Representation of the molecular solidꢀstate structure of
1
5
[
Ca{(PyCH)(Se)PPh } (THF) ] (2.945(1) Å) but it is much
2
2
2
2
,
[
Ca{L } ] (5). All hydrogen atoms are omitted for clarity.
2
25
shorter than in [Ca{Ph P(Se)ꢀNCH CH NPPh (Se)}·(THF) ]
i
2
2
2
2
3
60
Selected bond lengths (Å): Ca1−N1 2.451(1), Ca1−N1 2.451(1),
Ca1−N2 2.465(1), Ca1−N2 2.465(1), Ca1−S1 2.837(5), Ca1−S1
.837(5), Ca1−P1 3.189(4), Ca1−P1 3.189(4), S1−P1 1.981(6),
1
2d
(
3.252(2) Å) where the calcium centre is 7ꢀcoordinate.
i
i
2
The homoleptic complex [Ca{L } ] (5) was prepared in 67%
2
i
2
2
yield by the oneꢀpot treatment of {L }H, [KN(SiMe ) ] and CaI
3
2
2
P1−N2 1.629(1).
in 2:2:1 molar ratio in THF (Scheme 3). The analytical data
(NMR, combustion analysis) testify to its purity and show that no
THF is found in the complex.
30
65
Hydroelementation reactions: Preliminary investigations on the
performance of the heteroleptic complexes 2 and 3 as precatalysts
for the benchmark intermolecular hydrophosphination and
hydroamination of styrene were carried out. In a first set of
experiments, the addition of Ph PH to styrene was examined with
2
70
a
[
precatalyst
styrene] /[HPPh ] /[Ca]
0
loading
of
2.0
molꢀ%,
with
=
50:50:1. Characteristically for
0
2 0
17
calcium, it was found that the reaction was fully regioselective,
and afforded exclusively the antiꢀMarkovnikov product (Scheme
4
).
2
75
Scheme 3. Synthesis of the homoleptic complex [Ca{L } ] (5).
2
35
Its molecular structure was determined by single crystal Xꢀray
diffraction, and showed a sixꢀcoordinate calcium centre sitting in
i
a distorted octahedral environment (N2ꢀCa1ꢀN2 173.00 °) where
3
both ligands feature
κ
ꢀcoordination (Fig. 5). The details of
structural parameters are available in Table TS1 in the supporting
Scheme 4. Intermolecular hydrophosphination of styrene with
diphenylphosphine catalysed by 2 and 3.
40
information. In the complex 5, the metal coordination polyhedron
3
is formed by
κ
ꢀcoordination of the two monoanionic
−
{
Ph P(S)NHꢀC H CH=N(Dipp)} moieties. The Ca1−S distances
2
6
4
8
0
The reaction proceeds smoothly using complex 3 as precatalyst in
neat condition, achieving nearꢀcomplete conversion of 50 equiv
of neat substrates in 12 h (Table 1, entries 1ꢀ5). It also converted
of 2.8372(5) Å are expectedly shorter than the Ca−Se distance
(
3.0164(16) Å) observed in 3, but it resembles that in [Ca(Sꢀ
1
6
45
2,4,6ꢀtBu ꢀC H ) (THF) ] (2.8177(8) Å).
The solidꢀstate
3
6
2 2
4
5
9
3% of 400 equiv of substrates in the same amount of time (entry
), with a corresponding TOF of 18 molsubst molCa h .
structure of complex 5 is consistent with its NMR spectra in
solution, as only one set of resonances was detected in the spectra
–
1
–1
85
Precatalyst 2 was equally competent, compare entries 5 and 6.
4
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Table 1. Catalytic hydrophosphination of styrene with phosphine
catalysed by 2 and 3.
Table 2. Hydroamination of styrene with pyrrolidine catalysed by
calcium complex 3.
a
a
Time
h)
Conversion
(%)
Temp
°C)
Time
(h)
Conversion
(%)
Entry
Precat.
Solvent
Entry
Solvent
(
(
1
2
3
4
5
6
7
60
2
38
39
43
49
50
77
79
40
66
42
ꢀ (neat)
ꢀ (neat)
ꢀ (neat)
ꢀ (neat)
ꢀ (neat)
ꢀ (neat)
ꢀ (neat)
C D
1
2
3
4
5
6
3
3
3
3
3
2
2
2
3
1
16
23
32
47
93
94
8
ꢀ (neat)
ꢀ (neat)
ꢀ (neat)
ꢀ (neat)
ꢀ (neat)
ꢀ (neat)
C D
60
3
2
60
4
4
60
12
24
6
6
60
12
12
2
110
110
80
b
12
12
12
6
7
6
6
6
b
b
8
8
24
12
22
53
C D
6
6
6
c
9
80
ꢀ (neat)
Tolꢀd8
9
ꢀ (neat)
a
10
a
110
All reactions performed at 60 °C, using 2.0 molꢀ% of precatalyst unless
otherwise stated. Reactions in 0.3 mL of C
Precatalyst loading = 0.25 molꢀ%.
b
6
D
6
at 0.51 mM in substrates.
All reactions performed using 2.0 molꢀ% of precatalyst 3 unless
c
5
b
6 6
otherwise stated. Reactions in 0.3 mL of C D at 0.51 mM in substrates.
45
By contrast, the reactions were slower when performed in C D6
6
Conclusion
(entries 7ꢀ8). The poor conversion after 24 h perhaps reflects
catalyst decomposition under prolonger reaction time under these
experimental conditions. Only two calcium complexes, [{DippNꢀ
Tridentate monoanionic iminoꢀphosphinanilido chalcogenide
ligands have been introduced for the first time in calcium
chemistry, and have enabled the preparation of heteroleptic
calciumꢀamide complexes. The molecular solidꢀstate structures of
1
1
2
2
3
3
0
5
0
5
0
5
C H ꢀCH=N(Dipp)}CaN(SiMe ) (THF)]
and
[{BDI}CaNꢀ
6
4
3 2
(
SiMe ) (THF)], displayed overall better catalytic activity in this
3
2
5
5
6
0
5
0
6,8
reaction than complexes 2 and 3. Complex 3 was next
employed to catalyse the equimolar hydroamination of styrene
with pyrrolidine, using again a standard metal feed ratio of
the two calcium complexes 3 and 5 confirm that the ligand adopts
3
a
κ
ꢀcoordination mode, with effective coordination of the
chalcogen onto the calcium ion. The heteroleptic complexes 2
and 3 showed good performance in the antiꢀMarkovnikov
intermolecular hydrophosphination of styrene, but low activity in
the intermolecular hydroamination of that same substrate. It was
in particular found that the nature of the chalcogen element in the
ancillary ligand had little role in the ability of the resulting
complex to mediate with two benchmark reactions, highlighting
the limited ability of these soft atoms to influence the
coordination sphere of the hard, oxophilic calcium ion.
[
styrene] /[pyrrolidine] /[Ca] = 50:50:1. The reactions were
0 0 0
carried out in the temperature range 60ꢀ100 °C, either in neat
substrates or in aromatic solvents (Table 2). The catalysed
reactions were regiospecific, affording solely the antiꢀ
Markovnikov addition product. At 60 °C, the conversion reached
3
8% after 2 h at 60 °C (entry 1), and only modest progress was
observed beyond this time (entries 2ꢀ4) ; even after 24 h, only
half of the substrates were converted (entry 5), suggesting
catalyst deactivation. Only at 110 °C could significantly higher
conversions be observed (entries 6ꢀ7); in that case also, the
conversion reached a maximum of ca. 77ꢀ79%, no matter the
reaction was performed for 6 or 12 h. This suggests that, at higher
Experimental
General: All manipulations were performed under an inert atmosphere
temperature, the hydroelementation reaction is favoured over the 65 using standard Schlenk techniques or in a dry, solventꢀfree glove box
putative decomposition process, but that the latter process could
not be prevented eventually. The reactions were also sluggish in
dilute C D or tolueneꢀd solutions (entries 8 and 10). Hence the
(Jacomex; O
9.999% anhydrous beads) and HPPh
was dried and distilled over CaH and stored over 3 Å molecular sieves.
Compounds [O NC CH=N(Dipp)], and [H
were prepared by following literature protocols. Solvents (THF, Et
2
<1 ppm, H
2
2
O <5 ppm) for catalyst loading. CaI (Aldrich,
9
2
were used as received. Styrene
2
6
6
8
1
8
19
2
6
H
4
2
NC
6
H
4
CH=N(Dipp)]
O,
catalytic activity displayed by 3 in intermolecular hydroamination
7
7
8
0
5
0
2
is rather tame, and compares unfavourably with that of other
pentane, and toluene) were purified and dried (water contents all below 10
ppm) over alumina columns (MBraun SPS). THF was further distilled
under argon from sodium mirror/benzophenone ketyl prior to use. All
deuterated solvents (Eurisotop, Saclay, France) were stored in sealed
ampules over activated 3 Å molecular sieves and were thoroughly
degassed by several freeze−thaw−vacuum cycles. NMR spectra were
6
ꢀ10
calcium precatalysts.
Complex 2 showed very much the same
performance as 3.
1
31
1
recorded on Bruker AMꢀ400 and AMꢀ500 spectrometers. All H, P{ H},
13
1
and C{ H} chemical shifts were determined using residual signals of the
77
1
4
deuterated solvents and were calibrated vs SiMe and Se{ H} NMR
77
spectra were externally calibrated vs. Ph
Assignment of the signals was carried out using 1D ( H, C { H}) and 2D
COSY, HMBC, HMQC) NMR experiments. Coupling constants are
given in Hertz. Elemental analyses were performed on a Bruker Euro EA
2 2
Se (δ Se = +461 ppm).
1
13
1
Scheme 5. Intermolecular hydroamination of styrene with
pyrrolidine catalysed by the calcium complex 3.
(
4
0
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DOI: 10.1039/C6RA13117D
and highꢀresolution mass spectra (HRꢀMS) were recorded on an Agilent
538 UHD QꢀTOF using multimode source at the Indian Institute of
Technology Hyderabad (IITH), or on a Bruker MaXis 4G using
electrospray or ASAP sources at the University,of Rennes 1.
65 134.5 (oꢀPC
131.8 (pꢀPC
(mꢀPC ), 124.8 (mꢀNC
28.1 (CH(CH ), 23.3 (CH(CH
33 2
MHz, 25 ºC): δ = 49.8 ppm. Elem. anal. Calcd for C31H N
6
H
5
), 134.4 (oꢀPC
), 131.3 (C ), 131.2 (pꢀNC
), 120.5 (C ), 120.1 (NC
) ppm. P{ H} NMR (CDCl
PS (496.6 g
6
H
5
), 133.5 (oꢀNC
), 128.7 (mꢀPC
), 118.6 (C
, 161.9
6
H
3
), 131.9 (pꢀPC
), 128.6
),
6 5
H ),
6
6
H
5
6
H
4
6
H
3
6 5
H
6
H
5
6
H
3
6
H
4
6
H
4
6 4
H
3
1
1
3
)
2
3
)
2
3
5
0
5
0
5
0
5
0
5
0
5
0
0
–1
Ph
2
PHNC
6
H
4
CH=N(Dipp)] ({L }H). Triethylamine (1.5 mL, 12.8 70 mol ): C, 74.97; H, 6.70; N, 5.64; S, 6.46. Found: C, 74.69; H, 6.43; N,
+
mmol) and chlorodiphenylphosphine (1.9 mL, 10.7 mmol) were added to
a solution of [H NC CH=N(Dipp)] (3.0 g, 10.7 mmol) in toluene (50
5.49; S, 6.35. ESIꢀHRMS: [M + Na ] (C31
H
34
2
N PS) calcd m/z 519.1999,
2
6
H
4
found 519.1998.
mL). Immediate formation of a white turbidity was observed. The
reaction mixture was stirred overnight at room temperature. The insoluble
fraction (white solid, ammonium salt) was eliminated by cannula 75 elemental selenium (0.50 g, 6.45 mmol) were heated at 90 °C in toluene
filtration. Toluene was then removed in vacuo, giving a brown sticky
solid which was washed with pentane (2 × 20 mL) to yield the title
compound as an analytically pure pale yellow solid. Yield 4.1 g, 83%.
3
0
1
1
2
2
3
3
4
4
5
5
6
[Ph
2
P(Se)HNC
6
H
4
CH=N(Dipp)] ({L }H ). {L }H (2.0 g, 4.3 mmol) and
(30 mL) for 12 h. Unꢀreacted excess selenium was filtered off and the
filtrate was collected. After evaporation of the solvent, a light yellow
solid residue was obtained which was washed with pentane (2 × 10 mL)
to yield the title compound as a pale yellow solid. Yield 2.0 g, 85%.
1
3
H NMR (CDCl
NH), 8.27 (s, 1H; CH=N), 7.75 (dd, JHH = 8.3 Hz, JHH = 5.0 Hz, 1H;
NC ), 7.49 (complex m, 4H; PC ), 7.36 (m, 2H; PC ), 7.29
overlapping m, 6H; PC and C ), 7.13 (complex m, 3H; NC and
), 6.84 (t, JHH = 7.4 Hz, 1H; C ), 2.94 (sept, JHH = 8 Hz, 2H;
3
, 500.13 MHz, 25 ºC): δ = 10.28 (d, JHP = 9.1 Hz, 1H;
3
4
1
2
80 H NMR (CDCl
3
, 500.13 MHz, 25 ºC): δ = 11.44 (d, JHP = 9 Hz, 1H;
3
4
6
H
3
6
H
5
6 5
H
NH), 8.27 (s, 1H; CH=N), 7.98 (dd, JHH = 14.1 Hz, JHH = 7.1 Hz, 4H;
(
C
6
H
5
6
H
4
6
H
3
PC
PC
6
6
H
H
5
), 7.48 (overlapping m, 1H; NC
), 7.38 (complex m, 5H; PC and C
), 7.10 (s, 3H; NC and C
), 2.85 (sept, JHH = 8 Hz, 2H; CH(CH
6
H
3
), 7.42 (overlapping m, 2H;
H
6 4
3
3
6
H
4
6
H
4
5
6
H
5
), 7.25 (m, mixed with
3
13
1
3
CH(CH
(
3
)
2
), 1.08 (d, JHH = 6.9 Hz, 12H; CH(CH
3
)
2
) ppm; C{ H} NMR
), 148.4
solvent, 1H; C
85 1H; C
12H; CH(CH
166.2 (CH=N), 147.4 (iꢀN=CHC
134.5 (oꢀNC
131.7 (pꢀPC
6
H
4
6
H
3
6
H
4
) 7.0 (t, JHH = 7.4 Hz,
3
3
C
6
D
6
, 125.76 MHz, 25 ºC): δ = 166.2 (CH=N), 150.0 (iꢀNC
6
H
3
6
H
4
3
)
2
), 1.04 (d, JHH = 6.7 Hz,
13
1
(
iꢀNC
6
H
4
), 139.9 (iꢀPC
), 132.1 (pꢀNC
), 128.3 (mꢀPC
115.1 (C ), 114.9 (C
P{ H} NMR (CDCl ,161.9 MHz, 25 ºC): δ = 23.3 ppm. Elem. anal.
Calcd for C31 P (464.6 g mol ): C, 80.14; H, 7.16; N, 6.03. Found:
C, 79.88; H, 7.01; N, 5.81. ESIꢀHRMS: [M + H ] (C31
65.2459, found 465.2458.
6
H
5
), 138.1 (oꢀNC
), 131.2 (oꢀPC
), 124.8 (mꢀNC
) 27.9 (CH(CH
6
H
3
), 134.6 (C
), 131.1 (oꢀPC
), 119.0 (C
), 23.4 (CH(CH
6
H
4
), 132.1 (pꢀ
), 128.8 (mꢀ
3
)
2
) ppm. C{ H} NMR (C
), 143.3 (iꢀNC
), 133.0 (oꢀPC
), 131.5 (pꢀNC H3), 128.7 (mꢀPC
), 120.7 (C ), 120.2 (NC
), 23.3 (CH(CH ) ppm. P{ H} NMR (CDCl
6 6
D , 125.76 MHz, 25 ºC): δ =
NC
PC
6
H
3
6
H
H
3
6
H
5
6
H
5
6
H
4
6
H
3
), 138.0 (iꢀPC
6
6
6
H
5
),
),
),
6
H
5
6
5
6
H
3
6
H
4
), 117.3 (C
6
H
4
),
6
H
H
3
), 133.9 (oꢀNC
), 131.6 (C
), 124.8 (mꢀNC
6
H
3
6
H
5
), 131.9 (pꢀPC
H
5
6
H
4
6
H
4
3
)
2
3
)
2
) ppm;
6
5
6
H
4
6
H
5
3
1
1
3
90 128.5 (mꢀPC
(C ), 28.0 (CH(CH
161.9 MHz, 25 ºC): δ = 45.0 ( JPSe = 775 Hz) ppm. Se{ H} NMR
6
H
5
6
H
3
6
H
4
6 4
H ), 118.6
–1
31
1
H
33
N
2
6
H
4
3
)
2
3
)
2
3
,
+
1
77
1
34 2
H N P) calcd m/z
1
4
(CDCl
anal. Calcd for C31
34 2
(0.15 95 Found: C, 68.55; H, 6.16; N, 5.03. ESIꢀHRMS: [M + Na ] (C31H N PSe)
3
, 76.31 MHz, 25 ºC): δ = – 251 (d, JSeP = 776 Hz) ppm. Elem.
–1
33 2
H N PSe (543.5 g mol ): C, 68.50; H, 6.12; N, 5.15.
1
+
[
Ph
ml, 5 mmol) in water was added to a toluene solution (30 ml) of {L }H
2.0 g, 4.3 mmol). The reaction mixture was stirred for 6 h at room
2
P(O)HNC
6
H
4
CH=N(Dipp)] ({L }H). A 30% solution of H
2
O
2
0
calcd m/z 567.1444, found: 567.1442.
(
4
temperature. After removal of solvent, a half white solid residue was
obtained which was washed with pentane (2 × 10 mL) to yield the title
compound as an offꢀwhite solid. Yield 1.70 g, 85%.
[Ph P(BH )NH-C CH=N(Dipp) ({L }H). To a toluene solution (20
2
3
6 4
H
0
mL) of ({L }H) (2 g, 4.3 mmol), was added a boraneꢀdimethyl sulphide
100 (0.4 mL, 4.3 mmol) solution dropwise with stirring at room temperature.
The reaction mixture was then stirred for another 12 h. The solvent
1
2
H NMR (CDCl
3
, 500.13 MHz, 25 ºC): δ = 11.41 (d, JHP = 13.7 Hz, 1H;
3
4
4
NH), 8.30 (s, 1H; CH=N), 7.88 (dd, JHH = 12.5 Hz, JHH = 7.5 Hz, 4H;
PC
PC
and C
CH(CH
toluene was evaporated in vacuo. The compound ({L }H) was obtained
after washing with pentane (2 × 10 mL) as yellow solid. Yield: 2.0 g,
3
6
6
H
H
5
), 7.49 (t,
and C
J
HH = 7.6 Hz, 3H; NC
6
H
3
and PC
6
H
5
), 7.41 (m, 5H;
3
5
6
H
4
), 7.27 (d, JHH = 10.1 Hz, 1H; C
6
H
4
), 7.14 (s, 3H; NC
6
H
3
97%.
3
3
1
6
H
4
), 6.99 (t, JHH = 7.5 Hz, 1H; C
6
H
4
), 2.93 (sept, JHH = 8 Hz, 2H; 105 H NMR (CDCl , 400 MHz, 298 K): δ = 11.19 (d, J = 4.0 Hz, 1H; NH),
3
HP
3
13
1
3
)
2
), 1.09 (d, JHH = 6.8 Hz, 12H; CH(CH
3
)
2
) ppm. C{ H} NMR
), 143.6
), 132.3 (oꢀ
), 131.5 (pꢀ
), 124.8 (mꢀNC ), 120.2 110 Hz, 2H; CH(CH ) ), 2.11 (br, 3H, BH ), 1.06 (d, J = 6.7 Hz, 12H;
), 118.5 (C ), 28.1 (CH(CH
) ppm. P{ H} NMR (CDCl , 161.9 MHz, 25 ºC): δ = 19.0
PO (480.5 g mol ): C, 77.48; H,
6 5 HH
7.98 (s, 1H; CH=N), 7.95ꢀ7.90 (m, 4H; PC H ), 7.68 (d, J = 8, 1H;
3
(
(
C
6
D
6
, 125.76 MHz, 25 ºC): δ = 166.3 (CH=N), 147.7 (iꢀNC
) 138.1 (iꢀ PC ) 134.4 (oꢀNC ), 132.8 (C
), 132.1 (oꢀPC ), 131.8 (pꢀPC ), 131.6 (pꢀ PC
), 128.8 (mꢀPC ), 128.6 (mꢀPC
), 119.9 (C ), 119.9 (C
6
H
4
6 4 HH 6 3 6 4
C H ), 7.08 (t, J = 7.6 Hz, 3H; NC H and C H ), 7.05ꢀ7.01 (complex
3
iꢀNC
6
H
3
6
H
5
6
H
3
6
H
4
6 5 6 4 6 5 HH
m, 3H; PC H and C H ), 6.95ꢀ6.93 (m, 4H; PC H ), 6.86 (dt, J = 7.4
3
3
PC
NC
(
6
H
5
6
H
5
6
H
5
6
H
5
6 4 HH 6 4 HH
Hz, 1H; C H ), 6.58 (dt, J = 7.4 Hz, 1H; C H ), 2.98 (sept, J = 8
3
6
H
3
6
H
5
6
H
5
6 3
H
3
2
3
HH
1
3
C
6
H
4
6
H
4
6
H
4
6
H
4
3
)
2
), 23.3
3 2 6 6
CH(CH ) ) ppm; C{1H} NMR (C D , 125.8 MHz, 298 K): δ = 166.2
3
1
1
(
CH(CH
3
)
2
3
6 4 6 3 6 5
(CH=N), 147.4 (iꢀN=CHC H ), 143.3 (iꢀNC H ) 138.0 (iꢀPC H ) 134.5
(oꢀNC H ), 133.9 (oꢀNC H ), 133.0 (oꢀPC H ), 131.9 (pꢀPC H ), 131.7
6 3 6 3 6 5 6 5
(pꢀPC H ), 131.6 (C H ), 131.5 (pꢀNC H ), 128.7 (mꢀPC H ), 128.5 (mꢀ
–1
ppm. Elem. anal. calcd for C31
6.92; N, 5.83. Found: C, 77.19; H, 6.73, N, 5.63. ESIꢀHRMS: [M + Na ]
H
33
N
2
+
6
5
6
4
6
3
6
5
(C
31
H
34
N
2
PO) calcd m/z 503.2228, found 503.2226.
6 5 6 3 6 4 6 4 6 4
115 PC H ),124.8 (mꢀNC H ), 120.7 (C H ), 120.2 (NC H ), 118.6 (C H ),
31
1
2
3 2 3 2 3
8.0 (CH(CH ) ), 23.3 (CH(CH ) ) ppm; P{ H} NMR (CDCl , 161.9
MHz, 298 K): δ = 65.8 ppm; B{ H} NMR (128.4 MHz, CDCl , 298 K):
2
0
11
1
[Ph
2
P(S)HNC
6
H
4
CH=N(Dipp)] ({L }H). {L }H (2.0 g, 4.3 mmol) and
3
elemental sulphur (138 mg, 4.3 mmol) were heated at 90 °C in toluene
(30 mL) for 12 h. After evaporation of solvent, a pale yellow solid residue
was obtained which was washed with pentane (2 × 10 mL) to yield the 120 [{Ph P(S)NC H CH=N-(Dipp)}Ca{N(SiMe ) }(THF)] (2). THF (20
δ −36.05 ppm.
2
6
4
3 2
2
title compound as a pale yellow solid. Yield 1.9 g, 90 %.
mL) was added to a mixture of {L }H (0.3 g, 0.60 mmol) and
KN(SiMe ) (0.24 g, 1.2 mmol). The reaction mixture was stirred at room
temperature for 1 h, and was then added to a suspension of CaI (0.18 g,
1
2
H NMR (CDCl
3
, 500.13 MHz, 25 ºC): δ = 11.41 (d, JHP =10.2 Hz, 1H;
3
2
3
NH), 8.26 (s, 1H; CH=N), 7.97 (m, 4H; PC
6
H
5
), 7.47 (t, JHH = 8.1 Hz,
2
2H; NC
m, 5H; PC
Hz, 1H; C
Hz, 12H; CH(CH
6
H
3
and C
and C
), 2.85 (sept, JHH = 8 Hz, 2H; CH(CH
6
H
4
), 7.43 (complex m, 2H; PC
6 4
), 7.10 (s, 3H; NC and C H ), 6.98 (t, JHH = 7.4 125 the solvent was evaporated under vacuum and the residue was extracted
3
6
H
5
), 7.38 (overlapping
0.60 mmol) in THF (20 mL). After stirring at room temperature for 12 h,
3
6
H
5
6
H
4
6
H
3
3
6
H
4
3
)
2
), 1.04 (d, JHH = 6.8
, 125.76 MHz, 25 ºC): δ =
6 5
), 143.3 (iꢀNC ), 138.0 (iꢀ PC H )
with pentane (50 mL). After filtration to eliminate insoluble materials,
volatiles were removed in vacuo to afford the title compound as a pale
yellow solid. Yield (0.35 g, 75%).
13
1
3
)
2
) ppm. C{ H} NMR (C
6 6
D
1
66.2 (CH=N), 147.5 (iꢀN=CHC
6
H
4
6
H
3
6
| Journal Name, [year], [vol], 00–00
This journal is © The Royal Society of Chemistry [year]

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View Article Online
DOI: 10.1039/C6RA13117D
1
6 6 6 5
H NMR (C D , 500.13 MHz, 25 ºC): δ = 8.06 (m, 4H; PC H ), 7.91 (s, 65 Typical protocol for intermolecular hydroelementation reactions. In
3
4
1
7
6
H; CH=N), 7.11 (dd, JHH= 7.6 Hz, JHH = 2.8 Hz, 3H; NC
6
H
3
, PC
6
H
5
),
the glovebox, the precatalyst (10 ꢀL) was loaded into an NMR tube. The
NMR tube was stored in an appropriate Schlenk tube, which was then
removed from the gloveꢀbox to allow manipulations on a double manifold
Schlenk line. The subsequent manipulations were performed using
70 standard Schlenk techniques. Styrene (58ꢀL 500 ꢀmol) and
diphenylphosphine or pyrrolidine (500 ꢀmol) were added to the NMR
tube using microsyringes. The NMR tube was sealed and shaken
vigorously, then put into an oil bath at desire temperature. The reaction
times were measured from this point. After the required amount of time,
3
.05 (m, 2H; NC
6
H
3
), 7.0 (s, 4H; PC
.89 (d, JHH = 7.7 Hz, 1H; C ), 6.74 (td, JHH = 15.6 Hz, JHH = 1.6 Hz,
), 6.47 (t, JHH = 7.4 Hz, 1H; C ), 3.41 (br s, 4H; OCH CH ),
HH = 6.8 Hz, 6H;
6
H
5
), 6.95(d, JHH = 8.4 Hz, 1H, C H )
6 4
3
3
4
6
H
4
3
5
1H; C
3
CH(CH
CH(CH
6
H
4
6
H
4
2
2
3
3
.16 (sept,
J
HH = 8 Hz, 2H; CH(CH
), 1.08 (br s, 4H; OCH CH
) 0.38 (s, 18H, Si(CH ) ppm. C{ H} NMR (C
), 152.0 (iꢀNC
), 132.8 (oꢀPC
), 128.0 (pꢀNC H3), 126.3
) 123.4 (mꢀPC ) 123.3
), 68.7 (OCH CH ), 28.3 (CH(CH ),
), 22.4 (CH(CH ), 5.9 (Si(CH ) ppm.
,161.9 MHz, 25 ºC): δ = 40.6 ppm. Elem. anal. calcd
3 2
) ), 1.24 (d, J
3
3
)
)
2
2
2
), 0.93 (d,
J
HH= 6.7 Hz, 6H;
, 125.76
13
1
3
2
3
)
3
6 6
D
MHz, 25 ºC): δ = 171.5 (CH=N), 152.1 (iꢀN=CHC
149.6 (iꢀ PC ) 139.5 (oꢀNC ), 136.1 (oꢀNC
31.5 (pꢀPC ), 130.5 (C ), 128.1 (pꢀ PC
mꢀNC ), 126.2 (mꢀPC ), 125.7 (mꢀPC
), 123.2 (NC ), 118.2 (C
5.3 (CH(CH ), 24.5 (OCH CH
P{ H} NMR (C
for C41 OPSeSi
Found: C, 56.79; H, 6.63; N, 4.71.
6
H
4
6 3
H )
1
1
2
2
3
3
4
4
5
5
6
0
5
0
5
0
5
0
5
0
5
0
6
H
5
6
H
3
6
H
3
6 5
H ),
1
(
(
6
H
5
6
H
4
6
H
5
6
7
8
8
9
9
5
0
5
0
5
6 6
the reaction was quenched by adding C D to the mixture at room
temperature. The conversion was determined according to the H NMR
spectrum of the reaction mixture.
1
6
H
3
6
H
5
6
H
5
6
H
5
C
6
H
4
6
H
4
6
H
4
2
2
3 2
)
2
3
)
2
2
2
3
)
2
3 3
)
31
1
3
6
D
6
X-ray crystallographic analyses: Single crystals of complex {L }H were
–1
H58SrN
3
2
(862.6 g mol ): C, 57.08; H, 6.78; N, 4.87.
obtained from a concentrated solution of toluene at room temperature
while single crystals of complexes 3 and 5 were obtained from saturated
solution of pentane and diethylether respectively under argon atmosphere
at a temperature of –35 °C. In each case, a crystal of suitable dimensions
was mounted on a CryoLoop (Hampton Research Corp.) with a layer of
light mineral oil and placed in a nitrogen stream at 150(2) K. All
measurements were made either on an Agilent Supernova Xꢀcalibur Eos
CCD detector with either graphiteꢀmonochromatic CuꢀKα (1.54184 Å, for
Ph
same procedure as that described for 2, {L }H (0.35 g, 0.64 mmol),
KN(SiMe (0.26 g, 1.28 mmol) and CaI (0.19 g, 0.64 mmol) were
reacted in THF (20+20 mL) to afford the title compound as a pale yellow
solid. Yield (0.37 g, 71%). Light yellow crystals of 2 suitable for singleꢀ
crystal Xꢀray crystallography were obtained by storage of a concentrated
pentane solution at –30 ºC. H NMR (C
(
(
2 6 4 3 2
P(Se)NC H CH=N-(Dipp)}Ca{N(SiMe ) }(THF)] (3). Following the
3
3
)
2
2
3
L H and 5) or BrukerꢀAXS, APEXII CCD detector with MoꢀKα (0.71073
1
6
D
6
, 500.1 MHz, 298 K): δ = 8.06
), 7.92 (s, 1H; CH=N), 7.13
), 7.02 (complex m, 5H; PC and
) 6.86 (d, JHH = 7.7 Hz, 1H;
Å for 3) radiation. Crystal data and structure refinement parameters are
3
4
dd, JHH = 12.8 Hz, JHH = 7.7 Hz, 4H; PC
overlapping m, 3H; NC , PC
), 6.94 (d, JHH = 7.9 Hz, 2H; NC
6 5
H
summarised in Table TS1 in supporting information. The structures were
20
2
6
H
3
6
H
5
6
H
5
solved by direct methods (SIR2004) and refined on F using the fullꢀ
3
3
C
C
6
6
H
H
4
6
H
3
21
matrix leastꢀsquares method, using SHELXLꢀ97. Nonꢀhydrogen atoms
3
3
4
), 6.73 (t, JHH = 7.3 Hz, 1H; C
CH ), 3.23 (sept, JHH = 8 Hz, 2H; CH(CH
d, JHH = 6.6 Hz, 6H; CH(CH ), 1.09 (br s, 4H; OCH CH ), 0.95 (d,
) 0.37 (s, 18H, Si(CH ) ppm. C{ H}
, 125.76 MHz, 298 K): δ = 171.5 (CH=N), 152.2 (iꢀ
), 152.1 (iꢀNC ) 149.6 (iꢀ PC ) 139.5 (oꢀNC ), 135.8
), 132.7 (oꢀPC ), 131.8 (pꢀPC ), 130.6 (C ), 128.0 (pꢀ
), 127.9 (pꢀNC H3), 126.7 (mꢀNC ), 126.5 (mꢀPC ), 125.7 (mꢀ
), 123.9 (mꢀPC ), 123.7 (C ), 123.4 (NC ), 118.5 (C
CH ), 28.3 (CH(CH ), 25.4 (CH(CH ), 24.5 (OCH CH
2.4 (CH(CH ), 5.9 (Si(CH ) ppm. P{ H} NMR (C
6
H
4
), 6.46 (t, JHH = 7.3 Hz, 1H; C
6
H
4
),
were anisotropically refined. Hꢀatoms were included in the refinement on
calculated positions riding on their carrier atoms. The function minimised
3
3.43 (br s, 4H; OCH
2
2
) ), 1.29
3 2
3
(
3
)
2
2
2
2
2
2
2
2
2
was [∑w(Fo ꢀ Fc ) ] (w = 1 / [σ (Fo ) + (aP) + bP]), where P =
3
13
1
J
HH = 6.5 Hz, 6H; CH(CH
NMR (C
N=CHC
(oꢀNC
3
)
2
3
)
3
2
2
2
2
(
Max(Fo ,0) + 2Fc ) / 3 with σ (Fo ) from counting statistics. The
function R1 and wR2 were (Σ||Fo| ꢀ |Fc||) / Σ|Fo| and [Σw(Fo ꢀ Fc ) /
Σ(wFo )] respectively. The DIAMONDꢀ3 program was used to draw
6
D
6
2
2 2
6
H
4
6
H
3
6
H
5
6
H
3
4
1/2
6
H
3
6
H
5
6
H
5
6 4
H
the molecule. Crystallographic data (excluding structure factors) for the
00 structures reported in this article have been deposited with the Cambridge
PC
PC
6
H
H
5
6
6
H
3
6 5
H
1
6
5
6
H
5
H
6 4
6
H
4
6
H
4
),
),
Crystallographic Data Centre as supplementary publication nos. CCDC
6
2
8.7 (OCH
2
2
3
)
2
3
)
2
2
2
3
1
479903 (L H), 1479904 (3) and 1479905 (5). Copies of the data can be
3
1
1
3
)
2
3
)
3
6
D
6
, 161.9 MHz,
, 76.31
MHz, 298 K): δ = –61.0 (d, JSeP = 589 Hz) ppm. Elem. anal. calcd for
obtained free of charge on application to CCDC, 12 Union Road,
1
77
1
6 6
298 K): δ = 31.1 ( JPSe = 589 Hz ) ppm. Se{ H} NMR (C D
Cambridge CB21EZ, UK (fax:
05 deposit@ccdc.cam.ac.uk).
+
(44)1223ꢀ336ꢀ033; email:
1
1
–1
C
41
H58CaN
3
OPSeSi
2
(815.1 g mol ): C, 60.41; H, 7.17; N, 5.16. Found:
C, 59.99, H, 7.03; N, 4.93.
Acknowledgements
[Ca{Ph
as that described for 2, {L }H (0.3 g, 0.60 mmol), KN(SiMe
.60 mmol) and CaI (88 mg, 0.30 mmol) were reacted in THF (20+20
2
P(S)NC
6
H
4
CH=N-(Dipp)}
2
] (5). Following the same procedure
2
This work was supported by Science and Engineering Research
Board (SERB), Department of Science and Technology (DST),
3 2
)
(0.12 g,
0
2
mL) to afford the title compound as a pale yellow solid. Yield (0.208 g, 110 India under project no SB/S1/IC/045/2013. S. A. thanks CSIR for
6
7%). Light yellow crystals of 5 suitable for singleꢀcrystal Xꢀray
his PhD fellowship, and the Science and Technology Department,
Embassy of France in India, Bangalore, for travel grants towards
his research stay in Rennes.
crystallography were obtained by storage of a concentrated ether solution
1
at –30 ºC. H NMR (C
6
D
6
, 400 MHz, 298 K): δ = 8.13 (m, 8H; PC
, PC ), 7.06 (m, 10H; PC
) 6.89 (d, JHH = 7.8 Hz, 2H; C ), 6.78 (t,
), 2.89 (sept,
), 1.07 (d, JHH = 6.8 Hz, 24H; CH(CH ),
, 100 MHz, 298 K): δ = 171.2 (CH=N), 152.5 (iꢀ
), 152.2 (iꢀNC ) 149.1 (iꢀ PC ) 139.6 (oꢀNC ), 135.1
), 132.8 (oꢀPC ), 131.7 (pꢀPC ), 130.3 (C ), 128.0 (pꢀ
), 127.8 (pꢀNC H3), 126.9 (mꢀNC ), 126.4 (mꢀPC ), 125.9 (mꢀ
), 123.5 (mꢀPC ), 123.4 (C ), 123.1 (NC ), 118.5 (C ),
), 25.2 (CH(CH ), 22.1 (CH(CH ) ppm. P{ H} NMR
,161.9 MHz, 298 K): δ = 62.6 ppm Elem. anal. calcd for for
6 5
H ),
7
.88 (s, 2H; CH=N), 7.25 (m, 6H; NC
6
H
3
3
6
H
5
6 5
H
and C
6
H
4
), 6.99 (m, 4H, NC
6
H
3
6 4
H
3
3
115 Notes and references
J
HH = 7.4 Hz, 2H; C ), 6.48 (t, JHH = 7.6 Hz, 2H; C H
6
H
4
6 4
3
1
3
J
HH = 8 Hz, 4H; CH(CH
3
)
2
3 2
)
3
1
‡
Department of Chemistry, Indian Institute of Technology Hyderabad,
Kandi 502 285, Sangareddy, Telangana, India. Eꢀmail:
tpanda@iith.ac.in; Fax: + 91(40) 2301 6032; Tel: + 91(40) 2301 6036;
Institut des Sciences Chimiques de Rennes, UMR 6226 CNRS,
6 6
C{ H} NMR (C D
–
N=CHC
oꢀNC
6
H
4
6
H
3
6
H
5
6 3
H
(
6
H
3
6
H
5
6
H
5
6 4
H
§
PC
PC
2
6
H
H
5
6
6
H
3
6 5
H
1
20 Université de Rennes 1, Organometallics: Materials and Catalysis centre,
Campus de Beaulieu, Fꢀ35042 Rennes Cedex, France. Eꢀmail: jeanꢀ
francois.carpentier@univꢀrennes1.fr; yann.sarazin@univꢀrennes1.fr
6
5
6
H
5
H
6 4
6
H
4
6 4
H
3
1
1
8.2 (CH(CH
3
)
2
3
)
2
3 2
)
(C
6
D
H
6
–1
C
62
64CaN
4
P
2
S
2
(1030.4 g mol ): C, 72.20; H, 6.25; N, 5.43 Found: C,
†
Electronic Supplementary Information (ESI) available: Xꢀray
3
5
9.99, H, 7.03; N, 4.93.
crystallographic files for {L }H, 3 and 5 in CIF format, Table TS1 and the
This journal is © The Royal Society of Chemistry [year]
Journal Name, [year], [vol], 00–00 |
7

RSC Advances
Page 8 of 9
View Article Online
DOI: 10.1039/C6RA13117D
spectral data of new compounds, representation of the solidꢀstate structure
of 4. For crystallographic details in CIF see DOI: 10.1039/b000000x/
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0
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0
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1
10
10. For reviews covering the developments of Ae catalysts, see: (a) A.
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1. For the first mention of this complex, see: M. H. Chisholm, J.
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8
| Journal Name, [year], [vol], 00–00
This journal is © The Royal Society of Chemistry [year]

Page 9 of 9
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View Article Online
DOI: 10.1039/C6RA13117D
Calcium Complexes with Imino-phosphinanilido Chalcogenide Ligands for
Heterofunctionalisation Catalysis
‡
§
‡
Srinivas Anga, Jean-François Carpentier,* Tarun K. Panda,* Thierry
§
§
Roisnel, and Yann Sarazin*
‡
Department of Chemistry, Indian Institute of Technology Hyderabad, Ordnance Factory Estate,
Yeddumailaram 502205, Telangana, India.
§
Institut des Sciences Chimiques de Rennes, UMR 6226 CNRS, Université de Rennes 1,
Organometallics: Materials and Catalysis centre, Campus de Beaulieu, F-35042 Rennes Cedex,
France.
Table of content
The
syntheses,
characterisation
and
utilisation
of
the
calcium
complexes
x
[
{L }CaN(SiMe ) ·(THF)] supported by monoanionic, tridentate imino-phosphinanilido
3
2
–
2 –
3 –
chalcogenide ligands {Ph P(E)-N-C H -CH=N(Dipp)} (E = S, {L } ; E = Se, {L } ; Dipp = 2,6-
2
6
4
diisopropylphenyl) as molecular precatalysts for the heterofunctionalisation of styrene are
reported.