Ni(II), Pd(II) and Pt(II) complexes of PNP and PSP tridentate amino-phosphine ligands

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PAPER

Ni(II), Pd(II) and Pt(II) complexes of PNP and PSP tridentate

amino–phosphine ligands†

Michael J. Sgro and Douglas W. Stephan*

Received 16th February 2012, Accepted 21st March 2012

DOI: 10.1039/c2dt30373f

The ligands D((CH₂)₂NHPiPr₂)₂(D = NH 1, S 2) react with (dme)NiCl₂or (PhCN)₂MCl₂(M = Pd, Pt)

to give complexes of the form [D((CH₂)₂NHPiPr₂)₂MX]X (X = Cl, I; M = Ni, Pd, Pt) which were

converted to corresponding iodide derivatives by reaction with Me₃SiI. Reaction of 1 or 2 with

(COD)PdMeCl affords facile routes to [κ³P,N,P-NH((CH₂)₂NHPiPr₂)₂PdMe]Cl (8a) and [κ³P,S,P-S-

((CH₂)₂NHPiPr₂)₂PdMe]Cl (9a) in high yields. An alternative synthetic approach involves oxidative

addition of MeI to a M(0) precursor yielding [κ³P,N,P-HN(CH₂CH₂NHPiPr₂)₂NiMe]I (10), [κ³P,N,P-HN-

(CH₂CH₂NHPiPr₂)₂MMe]I (M = Pd 8b Pt 11) and [κ³P,S,P-S(CH₂CH₂NHPiPr₂)₂MMe]I (M = Pd 9b,

Pt 12). Alternatively, use of NEt₃HCl in place of MeI produces the species [κ³P,N,P-HN-

(CH₂CH₂NHPiPr₂)₂MH]X (X = Cl, M = Ni 13a, Pd 14a, Pt 16a). The analogs containing 2; [κ³P,S,

P-S((CH₂)₂NHPiPr₂)₂MH]X (M = Pd, X = PF₆15: M = Pt, X = Br, 17a, PF₆17b) were also prepared in

yields ranging from 74–93%. In addition, aryl halide oxidative addition was also employed to prepare

[κ³P,N,P-HN(CH₂CH₂NHPiPr₂)₂MC₆H₄F]Cl (M = Ni 18, Pd 19) and [κ³P,S,P-S((CH₂)₂NHPiPr₂)₂-

Pd(C₆H₄F)]Cl (20). Crystal structures of 3a, 4a, 5a, 6a, 8a, 9a, 14b and 16b are reported.

In our own efforts to develop new pincer ligand chemistry, we

Introduction

have developed the chemistry of tridentate bis-phosphinimine

ligands demonstrating that such ligands provide access to both

mono- and bimetallic systems.^24–27In exploring related ligand

systems, we have recently focused on amino-phosphine ligands.

While such ligands are easy to prepare, studies of the chemistry

of metal complexes with bidentate ligands containing these

donors has garnered limited attention.^28–33We have very recently

explored the complexation chemistry of related bidentate amino-

phosphines demonstrating that this functionality can in some

instances provide three-membered NPM rings.^34,35Related

studies of tridentate ligands incorporating aminophosphine

donors have received very limited attention^36–38prompting us to

explore synthetic routes to complexes of tridentate bis-amino-

phosphine ligands with central NH or S donors. In exploring the

chemistry of these ligands we have previously communicated

that while the ligand HN(CH₂CH₂NHPiPr₂)₂(1) provides access

to Ni(^II) products via subsequent reaction with acid, alkyl or aryl

halides the ligand S(CH₂CH₂NHPiPr₂)₂(2) undergoes oxidative

addition to Ni(0) to effect ligand cleavage³⁹(Scheme 1). In this

full report, we describe the direct synthetic routes to ligand–

metal halide cations, as well as oxidative addition routes to

alkyl, aryl and hydride complexes of Ni(^II), Pd(II) and Pt(II)

incorporating these tridentate aminophosphine ligands.

Tridentate ligand complexes have received considerable interest

over the past decade as the number of possible variations

afford applications in catalyst, sensor and switch technologies.¹

Phosphine-based PCP²and PNP³type ligands have garnered the

most attention demonstrating electronic and steric tunability, thus

rendering highly reactive species stable.^4–8In addition, such com-

plexes have displayed interesting reactivity including oxidative

addition of C–halogen bonds,^7,9C–H bond activation,⁶N₂acti-

vation and homolytic cleavage of H₂.^8,10Recent work has demon-

strated that Group 10 complexes containing tridentate ligands,

speciﬁcally those species containing M–X bonds (M = Ni, Pd;

X = H, alkyl, aryl), are of particular importance as they are often

implicated as intermediates in catalytic transformations and have

interesting reactivity. The nucleophilic M–X bonds of these com-

plexes have been shown to insert CO₂, and in some cases allow

for its reduction into value-added products.^11–16In addition, the

insertion of oleﬁns into the M–X bonds serves as the (re)initiation

step in oleﬁn polymerization, making the isolation of these

species desirable as they may serve as active catalysts.^17–20More

recently, Milstein et al. have focused attention on dissymmetric

pincer ligands as such systems appear to employ the non-inno-

cence of the ligand to generate unique reactivity.^21–23

Experimental section

Department of Chemistry, University of Toronto, 80 St George St,

Toronto, Ontario, Canada, M5S3H6. E-mail: dstephan@

chem.utoronto.ca; Tel: +01-416-946-3294

†CCDC reference numbers 867384–867392. For crystallographic data

in CIF or other electronic format see DOI: 10.1039/c2dt30373f

All preparations were performed under an atmosphere of dry,

O₂-free N₂employing both Schlenk line techniques and inert

atmosphere glove boxes. Solvents (THF, CH₂Cl₂, Et₂O hexane

This journal is © The Royal Society of Chemistry 2012

Dalton Trans., 2012, 41, 6791–6802 | 6791

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3

CH₂N), 2.82 (t, 4H, J_HH6 Hz, (NH)–CH₂), 2.11 (br, 2H, NH),

3

1.60 (sept, 4H, J_HH7 Hz, Me₂CH), 0.99 (m, 24H, Me₂CH).

3

2

¹³C{¹H} (CD₂Cl₂) 52.38 (d, J_CP6 Hz, CH₂), 46.21 (d, J_CP

1

2

29 Hz, CH₂N), 27.02 (d, J_CP12 Hz, Me₂CH), 19.81 (d, J_CP

2

21 Hz, Me₂CH), 17.95 (d, J_CP8 Hz, Me₂CH)). ³¹P{¹H}

(CD₂Cl₂) 70.73 (s).

Synthesis of [κ³P,N,P-NH((CH₂)₂NHPiPr₂)₂NiCl]Cl (3a),

[κ³P,S,P-S((CH₂)₂NHPiPr₂)₂NiCl]Cl (5a)

These complexes were prepared in a similar fashion and thus

only one preparation is detailed. A solution of 1 (100 mg,

0.298 mmol) in CH₂Cl₂(2 mL) was added to a yellow-orange

suspension of (dme)NiCl₂(66 mg, 0.298 mmol) and CH₂Cl₂

(2 mL) in a scintillation vial equipped with a stir bar giving an

immediate change to a clear orange solution. The reaction

mixture was stirred for 4 hours at which point the orange sol-

ution was dried to a bright orange solid. The solid was washed

with hexane (3 × 4 mL) and the solution was decanted of the

solid before it was dried in vacuo. The product was recrystallized

from the diffusion of pentane into a DCM solution. The orange

product was obtained in 90% yield (125 mg, 0.268 mmol).

3a: ¹H (CD₂Cl₂) 4.73 (bs, 1H, NH), 3.57 (bm, 2H, CH₂), 3.25

(bm, 2H, CH₂), 2.95 (bm, 2H, CH₂), 2.69 (bm, 2H, CH₂), 2.45

Scheme 1 Reactions of aminophosphine tridentate ligands with Ni-

(COD)₂and substrates.

and pentane) were puriﬁed employing a Grubbs’ type column

system manufactured by Innovative Technology. Solvents were

stored in the glove box over 4 Å molecular sieves. ¹H, ¹³C{¹H},

¹⁹F{¹H} and ³¹P{¹H} NMR spectra were acquired on a Bruker

Avance 400 MHz spectrometer or a Varian Mercury 400 MHz

spectrometer. ¹H and ¹³C NMR were internally referenced to

CD₂Cl₂relative to SiMe₄. NMR samples were prepared in the

glove box, capped and sealed with paraﬁlm. ¹⁹F resonances

were referenced externally to CFCl₃and ³¹P resonances were

referenced externally to 85% H₃PO₄. ¹H–¹³C HSQC experiments

were carried out using conventional pulse sequences to aid in the

assignment of peaks in the ¹³C{¹H} NMR spectroscopy. Coup-

ling constants (J) are reported as absolute values in Hz.

All glassware was dried overnight at 120 °C and evacuated for

1 hour prior to use. Combustion analyses were performed

in-house employing a Perkin Elmer 2400 Series II CHNS Analy-

zer. CD₂Cl₂was purchased from the Cambridge Isotope Labora-

tories and was dried over CaH₂, distilled, degassed and stored

under N₂in a glove box. Ni(COD)₂, Pd(PPh₃)₄, Pt(PPh₃)₄,

(dme)NiCl₂, PhCN₂PdCl₂, PhCN₂PtCl₂, NiI₂, PdI₂and PtI₂

were obtained from Strem Chemicals Inc. iPr₂PCl, Et₃N,

HN(CH₂CH₂NH₂)₂, [NH₄][PF₆], MeI and 1-Cl-2-F-C₆H₄were

obtained from Aldrich Chemical Co. S(CH₂CH₂NH₂)₂was

obtained from TCI America. All of the reagents from Aldrich

Chemical Co., TCI America and Strem Chemical Inc. were used

without further puriﬁcation. Hyﬂo Super Cel® (Celite) was pur-

chased from Aldrich and dried for at least 12 h in a vacuum oven

or on a Schlenk line prior to use. Molecular sieves (4 Å) were

purchased from Aldrich and dried at 100 °C under vacuum using

a Schlenk line. Compound 1 and 2 were prepared as previously

reported.³⁹

3

(bs, 2H, NH), 2.28 (sept, 4H, J_HH7 Hz, CHMe₂), 1.55

(m, 12H, ³J_HH7 Hz, CHMe₂), 1.32 (m, 6H, ³J_HH7 Hz, CHMe₂),

3

1.19 (m, 6H, J_HH7 Hz, CHMe₂). ¹³C{¹H} (CD₂Cl₂) 52.26 (bs,

1

CH₂), 42.19 (bs, CH₂), 27.69 (vt, J_CP15 Hz, Me₂CH), 27.36

1

2

(vt, J_CP14 Hz, Me₂CH), 19.72 (d, J_CP5 Hz, Me₂CH), 18.27

(s, Me₂CH), 16.83 (s, Me₂CH). ³¹P{¹H} (CD₂Cl₂) 62.62 (s).

Anal. Calc. for C₁₆H₃₉N₃P₂NiCl₂: C, 41.30; H, 8.46; N, 9.04.

Found: C, 41.06; H, 8.44; N, 9.17.

5a: Starting with 2 (100 mg, 0.284 mmol) and dmeNiCl₂

(62 mg, 0.284 mmol), the orange product was obtained in 93%

yield (127 mg, 0.263 mmol). ¹H (CD₂Cl₂) 3.99 (m, 2H,

3

NHPⁱPr₂), 3.42 (m, 4H, J_HH5 Hz, CH₂NHPiPr₂), 2.65 (t, 4H,

3

³J_HH5 Hz, SCH₂), 2.45 (sept, 4H, J_HH7 Hz, CHMe₂), 1.51

3

(m, 12H, J_HH7 Hz, CHMe₂), 1.34 (m, 12H, J_HH7 Hz,

CHMe₂). ¹³C{¹H} (CD₂Cl₂) 43.22 (s, CH₂), 34.31 (s, CH₂),

1

28.22 (vt, J_CP115 Hz, Me₂CH), 19.75 (s, Me₂CH), 17.54

(s, Me₂CH). ³¹P{¹H} (CD₂Cl₂) 68.54 (s). Anal. Calc. for

C₁₆H₃₈N₂P₂SNiCl₂: C, 39.85; H, 7.95; N, 5.81. Found: C,

39.93; H, 8.00; N, 6.10.

Synthesis of [κ³P,N,P-NH((CH₂)₂NHPiPr₂)₂NiI]I (3b),

[κ³P,S,P-S((CH₂)₂NHPiPr₂)₂NiI]I (5b)

Synthesis of NH((CH₂)₂NHPiPr₂)₂·HCl (1·HCl)

These complexes were prepared in a similar fashion and thus

only one preparation is detailed. A solution of 1 (54 mg,

0.160 mmol) in CH₂Cl₂(2 mL) was added to a black slurry of

NiI₂(50 mg, 0.160 mmol) and CH₂Cl₂(2 mL) in a scintillation

vial equipped with a stir bar. No immediate color change was

observed. The reaction mixture was stirred for 12 hours at which

point the purple solution was dried to a red-purple solid.

The solid was washed with hexane (3 × 4 mL) and the solution

was decanted of the solid before it was dried in vacuo. The

product was recrystallized from the diffusion of pentane into a

CH₂Cl₂solution. The purple product was obtained in 83% yield

A 250 mL round bottom Schlenk ﬂask was charged with 1 (1 g,

2.981 mmol) and 50 mL of Et₂O and stirred under nitrogen.

A solution of HCl in Et₂O (2 M, 1.49 mL, 2.981 mmol) was

added dropwise over 5 min giving an immediate change from a

clear colorless solution to a cloudy white mixture. The reaction

was stirred for 30 min before being ﬁltered through a ﬁne poro-

sity ﬁlter frit. The white solid was washed with Et₂O (5 mL × 3

times) and dried in vacuo. The product was obtained as a waxy

1

white solid in 90% (998 mg, 2.683 mmol) yield. H (CD₂Cl₂)

7.66 (b, 1H, CH₂NHCH₂), 3.21 (d of t, 4H, J_HH6, J_HP9,

3

6792 | Dalton Trans., 2012, 41, 6791–6802

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1

(86 mg, 0.133 mmol). 3b: H (CD₂Cl₂) 3.49 (bm, 2H, CH₂),

0.139 mmol) in CH₂Cl₂(2 mL) was added to a black slurry of

PdI₂(50 mg, 0.139 mmol) in CH₂Cl₂(2 mL) in a scintillation

vial equipped with a stir bar. No immediate change is observed

but after 12 h a cloudy yellow solution is obtained. The reaction

mixture was stirred for 12 hours at which point the cloudy

yellow solution was ﬁltered through Celite to remove black

particulate before being dried to a bright yellow solid. The solid

was washed with hexane (3 × 4 mL) and the solution was de-

canted of the solid before it was dried in vacuo. The product was

recrystallized from the diffusion of pentane into a CH₂Cl₂solu-

tion. The yellow product was obtained in 85% yield (82 mg,

0.118 mmol).

3.44 (bs, 1H, NH), 3.34 (bm, 2H, CH₂), 3.01 (bm, 2H, CH₂),

2.91 (bm, 2H, CH₂), 2.52 (sept, 2H, J_HH7 Hz, CHMe₂), 2.46

(sept, 2H, J_HH7 Hz, CHMe₂), 2.23 (bs, 2H, NH), 1.55 (m,

3

12H, J_HH7 Hz, CHMe₂), 1.47 (m, 6H, J_HH7 Hz, CHMe₂),

1.35 (m, 6H, J_HH7 Hz, CHMe₂). ¹³C{¹H} (CD₂Cl₂) 48.06 (vt,

3

J

_CP4 Hz, CH₂), 41.08 (vt, J_CP2 Hz, CH₂), 31.55 (t, ¹J_CP16 Hz,

1

2

Me₂CH), 28.73 (t, J_CP15 Hz, Me₂CH), 20.17 (d of t, J_CP

7 Hz, ²J_CP2 Hz, Me₂CH), 18.16 (s, Me₂CH), 17.51 (s, Me₂CH).

³¹P{¹H} (CD₂Cl₂) 78.20 (s). Anal. Calc. for C₁₆H₃₉N₃P₂NiI₂:

C, 29.64; H, 6.07; N, 6.49. Found: C, 29.85; H, 5.86; N, 6.81.

5b: Starting with 2 (56 mg, 0.160 mmol) and NiI₂(50 mg,

0.160 mmol), the red product was obtained in 87% yield

1

4b: H (CD₂Cl₂) 4.85 (bs, 1H, NH), 3.53 (m, 2H, CH₂), 3.26

1

3

(92 mg, 0.139 mmol). H (CD₂Cl₂) 3.47 (m, 4H, J_HH5 Hz,

CH₂), 2.82 (m, 4H, J_HH5 Hz, CH₂), 2.77 (m, 2H, NH), 2.72

(m, 2H, CH₂), 3.13 (m, 2H, CH₂), 2.82 (m, 2H, CH₂), 2.64

3

(m, 2H, J_HH7 Hz, CHMe₂), 2.58 (m, 2H, J_HH7 Hz, CHMe₂),

3

(m, 4H, J_HH7 Hz, CHMe₂), 1.50 (m, 12H, J_HH7 Hz,

2.44 (bs, 2H, NH), 1.39 (m, 18H, J_HH7 Hz, CHMe₂), 1.24

CHMe₂), 1.32 (m, 12H, J_HH7 Hz, CHMe₂). ¹³C{¹H} (CD₂Cl₂)

(m, 6H, J_HH7 Hz, CHMe₂). ¹³C{¹H} (CD₂Cl₂) 53.71 (vt, J_CP

3

1

43.13 (vt, J_CP2 Hz, CH₂), 34.84 (vt, J_CP3 Hz, CH₂), 31.97

2 Hz, CH₂), 43.15 (vt, J_CP2 Hz, CH₂), 30.05 (t, J_CP19 Hz,

1

2

1

2

(t, J_CP16 Hz, Me₂CH), 20.37 (t, J_CP2 Hz, Me₂CH), 18.14

(d, ²J_CP2 Hz, Me₂CH). ³¹P{¹H} (CD₂Cl₂) 78.42 (s). Anal. Calc.

for C₁₆H₃₈N₂P₂SNiI₂: C, 28.88; H, 5.76; N, 4.21. Found: C,

28.49; H, 5.76; N, 4.36.

Me₂CH), 28.80 (t, J_CP19 Hz, Me₂CH), 19.56 (d, J_CP2 Hz,

Me₂CH), 19.22 (d, ²J_CP2 Hz, Me₂CH), 18.08 (s, Me₂CH), 17.03

(s, Me₂CH). ³¹P{¹H} (CD₂Cl₂) 77.8 (s). Anal. Calc. for

C₁₆H₃₉N₃P₂PdI₂: C, 27.61; H, 5.65; N, 6.04. Found: C, 28.08;

H, 5.35; N, 5.97.

6b: Starting with 2 (49 mg, 0.139 mmol) and PdI₂(50 mg,

0.139 mmol), the yellow product was obtained in 81% yield

Synthesis of [κ³P,N,P-NH((CH₂)₂NHPiPr₂)₂PdCl]Cl (4a),

[κ³P,S,P-S((CH₂)₂NHPiPr₂)₂PdCl]Cl (6a)

1

3

(80 mg, 0.113 mmol). H (CD₂Cl₂) 3.46 (m, 4H, J_HH5 Hz,

3

CH₂), 3.10 (m, 2H, NH), 2.93 (m, 4H, J_HH5 Hz, CH₂), 2.76

These complexes were prepared in a similar fashion to 3a and 5a

and thus only the amounts of starting materials are detailed.

4a: Starting with 1 (100 mg, 0.298 mmol) and (PhCN)₂PdCl₂

(114 mg, 0.298 mmol) the yellow product was obtained in 94%

3

(sept, 4H, J_HH7 Hz, CHMe₂), 1.50 (m, 12H, J_HH7 Hz,

CHMe₂), 1.32 (m, 12H, J_HH7 Hz, CHMe₂). ¹³C{¹H} (CD₂Cl₂)

3

45.60 (vt, J_CP3 Hz, CH₂), 36.25 (vt, J_CP2 Hz, CH₂), 31.33

1

2

(t, J_CP16 Hz, Me₂CH), 19.73 (t, J_CP2 Hz, Me₂CH), 17.86

(s, Me₂CH). ³¹P{¹H} (CD₂Cl₂) 77.88 (s). Anal. Calc. for

C₁₆H₃₈N₂P₂SPdI₂: C, 26.95; H, 5.38; N, 3.93. Found: C, 27.38;

H, 5.69; N, 4.04.

1

yield (144 mg, 0.280 mmol). H (CD₂Cl₂) 6.43 (bs, 1H, NH),

3

3.62 (m, 2H, J_HH7 Hz, CH₂), 3.26 (m, 2H, J_HH7 Hz, CH₂),

2.97 (m, 2H, CH₂), 2.75 (m, 2H, CH₂), 2.50 (bs, 2H, NH),

3

2.47 (d of sept, 2H, J_HH7 Hz, CHMe₂), 2.39 (d of sept, 2H,

3

³J_HH7 Hz, CHMe₂), 1.36 (m, 18H, J_HH7 Hz, CHMe₂), 1.23

(m, 6H, ³J_HH7 Hz, CHMe₂). ¹³C{¹H} (CD₂Cl₂) 55.06 (vt, J_CP

3

Synthesis of [κ³P,S,P-S((CH₂)₂NHPiPr₂)₂PtCl]Cl (7a)

1

Hz, CH₂), 44.09 (vt, J_CP2 Hz, CH₂), 28.31 (vt, J_CP15 Hz,

1

Me₂CH), 27.58 (vt, J_CP16 Hz, Me₂CH), 19.40 (s, Me₂CH),

This product was prepared in a similar fashion to 6a starting

with 2 (100 mg, 0.284 mmol) and (PhCN)₂PtCl₂(134 mg,

0.284 mmol). The white product was obtained in 88% yield

17.68 (s, Me₂CH), 16.83 (s, Me₂CH). ³¹P{¹H} (CD₂Cl₂)

71.62 (s). Anal. Calc. for C₁₆H₃₉N₃P₂PdCl₂: C, 37.46; H, 7.67;

N, 8.20. Found: C, 37.92; H, 7.92; N, 8.17.

1

(155 mg, 0.250 mmol). H (CD₂Cl₂) 4.10 (bs, 2H, NHPⁱPr₂),

6a: Starting with 4 (100 mg, 0.284 mmol) and (PhCN)₂PdCl₂

(109 mg, 0.160 mmol), the yellow product was obtained in 92%

yield (138 mg, 0.261 mmol). ¹H (CD₂Cl₂) 3.95 (bs, 2H,

3.47 (m, 4H, CH₂NHPiPr₂), 3.07 (m, 4H, SCH₂), 2.66 (m, 4H,

CHMe₂), 1.29 (m, 24H, CHMe₂). ¹³C{¹H} (CD₂Cl₂) 45.55

1

(vt, J_CP3 Hz, CH₂), 37.17 (vt, J_CP3 Hz, CH₂), 27.33 (vt, J_CP

NHPⁱPr₂), 3.47 (m, 4H, J_HH5 Hz, CH₂NHPiPr₂), 2.87 (t, 4H,

15 Hz, Me₂CH), 19.47 (bs, Me₂CH). ³¹P{¹H} (CD₂Cl₂) 66.09

3

2

³J_HH5 Hz, SCH₂), 2.58 (sept, 4H, J_HH7 Hz, CHMe₂), 1.35

(t, J_PPt2312 Hz). Anal. Calc. for C₁₆H₃₈N₂P₂SPtCl₂: C, 31.06;

3

(m, 12H, J_HHHz, CHMe₂), 1.28 (m, 12H, J_HH7 Hz, CHMe₂).

H, 6.19; N, 4.53. Found: C, 30.78; H, 6.14; N, 4.41.

¹³C{¹H} (CD₂Cl₂) 45.72 (vt, J_CP3 Hz, CH₂), 36.10 (vt, J_CP

2

1

2

Hz, CH₂), 28.03 (t, J_CP15 Hz, Me₂CH), 19.04 (d, J_CP2 Hz,

Me₂CH), 17.35 (s, Me₂CH). ³¹P{¹H} (CD₂Cl₂) 76.97 (s). Anal.

Calc. for C₁₆H₃₈N₂P₂SPdCl₂: C, 36.26; H, 7.23; N, 5.29.

Found: C, 36.82; H, 7.40; N, 5.41.

Synthesis of [κ³P,S,P-S((CH₂)₂NHPiPr₂)₂PtI]I (7b)

This product was prepared in a similar fashion to 6b starting

with 2 (37 mg, 0.111 mmol) and PtI₂(50 mg, 0.111 mmol).

The off-white product was obtained in 77% yield (67 mg,

1

0.085 mmol). H (CD₂Cl₂) 3.50 (bm, 4H, CH₂), 3.22 (bm, 2H,

Synthesis of [κ³P,N,P-NH((CH₂)₂NHPiPr₂)₂PdI]I (4b),

[κ³P,S,P-S((CH₂)₂NHPiPr₂)₂PdI]I (6b)

3

NH), 3.10 (bm, 4H, CH₂), 2.87 (sept, 4H, J_HH7 Hz, CHMe₂),

3

1.33 (m, 12H, J_HH6 Hz, CHMe₂), 1.27 (m, 12H, J_HH7 Hz,

These complexes were prepared in a similar fashion and thus

only one preparation is detailed. A solution of 1 (47 mg,

CHMe₂). ¹³C{¹H} (CD₂Cl₂) 45.09 (vt, J_CP2 Hz, CH₂), 37.22

(vt, J_CP2 Hz, CH₂), 30.08 (vt, J_CP19 Hz, Me₂CH), 19.19

1

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2

3

(vt, J_CP5 Hz, Me₂CH), 17.57 (bs, Me₂CH). ³¹P{¹H} (CD₂Cl₂)

³J_HH7 Hz, NH), 3.38 (m, 4H, J_HH5 Hz CH₂), 2.82 (t, 4H,

1

3

64.08 (t, J_PPt2277 Hz). Anal. Calc. for C₁₆H₃₈N₂P₂SPdI₂: C,

23.97; H, 4.78; N, 3.50. Found: C, 23.98; H, 5.10; N, 3.41.

³J_HH5 Hz, SCH₂), 2.27 (sept, 4H, J_HH7 Hz, CHMe₂), 1.25

3

(m, 12H, J_HH7 Hz, CHMe₂), 1.18 (m, 12H, J_HH7 Hz,

CHMe₂), 0.51 (t, 3H, J_HP7 Hz, Pd–CH₃). ¹³C{¹H} (CD₂Cl₂)

3

1

46.97 (vt, J_CP4 Hz, CH₂), 38.83 (s, CH₂), 26.75 (vt, J_CP15

2

Alternative synthesis of 3b, 4b, 5b, 6b, 7b

Hz, CHMe₂), 18.79 (vt, J_CP3 Hz, CHMe₂), 17.11 (s, CHMe₂),

−6.15 (t, J_CP6 Hz, PdMe). ³¹P{¹H} (CD₂Cl₂) 81.12 (s). Anal.

2

These complexes were prepared in a similar fashion and thus

only one preparation is detailed. An orange suspension of 2a in

CH₂Cl₂(50 mg, 0.107 mmol; 2 mL) was prepared in a 4 dram

vial equipped with a stir bar. Neat Me₃SiI (31 μL, 0.215 mmol)

was added giving an immediate change to a clear deep purple

solution. The reaction mixture was stirred for 2 h at which point

³¹P{¹H} indicated quantitative conversion to 2b. The volatiles

were removed and the purple solid was redissolved in CH₂Cl₂

(1 mL) and layered with pentane. The product was obtained in

93% yield (64 mg, 0.100 mmol).

3b: Starting with 3a (50 mg, 0.097 mmol) and Me₃SiI

(28 μL, 0.215 mmol), the yellow product was obtained in 91%

yield (61 mg, 0.088 mmol).

5b: Starting with 5a (50 mg, 0.103 mmol) and Me₃SiI

(30 μL, 0.207 mmol), the yellow product was obtained in 92%

yield (63 mg, 0.095 mmol).

Calc. for C₁₇H₄₁ClN₂P₂PdS: C, 40.07; H, 8.12; N, 5.50; Found:

C, 39.87; H, 7.55; N, 5.46.

Synthesis of [κ³P,N,P-NH((CH₂)₂NHPiPr₂)₂PdMe]I (8b) and

[κ³P,S,P-S((CH₂)₂NHPiPr₂)₂PdMe]I (9b)

These complexes were prepared in a similar fashion and thus

only one preparation is detailed. A solution of 1 in THF (58 mg,

0.173 mmol; 2 mL) was added to a yellow slurry of (PPh₃)₄Pd

and THF (200 mg, 0.173 mmol; 2 mL) in a scintillation vial

equipped with a stir bar. The solution was stirred for 30 min

yielding no observable change before iodomethane (25 mg,

0.173 mmol; neat) was added. A white precipitate forms almost

immediately. The reaction mixture was stirred for 12 hours at

which point it was concentrated before hexane was added to pre-

cipitate a ﬂuffy white powder. The supernatant was removed and

the white powder was dried. The crude product was washed with

hexane (3 × 4 mL) and the solution was decanted off before the

product was dried in vacuo. The product was recrystallized from

the diffusion of pentane into a CH₂Cl₂solution. The white

product was obtained in 88% yield (89 mg, 0.152 mmol).

6b: Starting with 6a (50 mg, 0.094 mmol) and Me₃SiI

(27 μL, 0.189 mmol), the yellow product was obtained in 96%

yield (64 mg, 0.090 mmol).

7b: Starting with 7a (50 mg, 0. 081 mmol) and Me₃SiI

(23 μL, 0.162 mmol), the off white product was obtained in

89% yield (58 mg, 0.072 mmol).

8b: ¹H (CD₂Cl₂) 3.40 (bs, 1H, NH), 3.37 (m, 2H, CH₂),

3.30 (m, 2H, CH₂), 3.10 (m, 2H, CH₂), 2.58 (m, 2H, CH₂), 2.49

(bt, 2H, J_HH5 Hz, NH), 2.22 (sept, 2H, J_HH7 Hz, CHMe₂),

2.13 (sept, 2H, J_HH7 Hz, CHMe₂), 1.31 (m, 6H, J_HH7 Hz,

Synthesis of [κ³P,N,P-NH((CH₂)₂NHPiPr₂)₂PdMe]Cl (8a),

[κ³P,S,P-S((CH₂)₂NHPiPr₂)₂PdMe]Cl (9a)

3

These complexes were prepared in a similar fashion and thus

only one preparation is detailed. A solution of 1 in THF

(127 mg, 0.377 mmol; 2 mL) was added to an off-white slurry

of (COD)PdMeCl and THF (100 mg, 0.377 mmol; 2 mL) in a

scintillation vial equipped with a stir bar. An off-white precipi-

tate immediately forms in a colorless solution. The reaction

mixture was stirred for 4 hours at which point it was dried to a

pale yellow-white solid. The crude product was washed with

hexane (3 × 4 mL) and the solution was decanted off before the

product was dried in vacuo. The product was recrystallized from

the diffusion of pentane into a CH₂Cl₂solution. The off-white

product was obtained in 87% yield (161 mg, 0.328 mmol).

CHMe₂), 1.22 (m, 18H, J_HH7 Hz, CHMe₂), 0.22 (t, 3H, J_HP

7 Hz, PdMe). ¹³C{¹H} (CD₂Cl₂) 54.61 (vt, J_CP2 Hz, CH₂),

1

45.19 (vt, J_CP4 Hz, CH₂), 27.05 (vt, J_CP15 Hz, CHMe₂),

26.68 (vt, J_CP13 Hz, CHMe₂), 18.98 (vt, J_CP3 Hz, CHMe₂),

1

2

18.89 (vt, J_CP3 Hz, CHMe₂), 17.79 (s, CHMe₂), 16.74

(s, CHMe₂), −12.66 (t, J_CP7 Hz, PdMe). ³¹P{¹H} (CD₂Cl₂)

2

79.62 (s). Anal. Calc. for C₁₇H₄₂N₃P₂PdI: C, 34.95; H, 7.25; N,

7.20; Found: C, 35.07; H, 7.12; N, 7.11.

9b: Starting with 2 (58 mg, 0.173 mmol), (PPh₃)₄Pd (100 mg,

0.173 mmol), and CH₃I (25 mg, 0.173 mmol) the white solid

was obtained in a 76% yield. H (CD₂Cl₂) 3.40 (m, 4H, J_HH

5 Hz CH₂), 2.91 (bt, 2H, NH), 2.86 (t, 4H, J_HH5 Hz, S–CH₂),

1

3

1

3

8a: H (CD₂Cl₂) 3.89 (bs, 1H, NH), 3.30 (m, 4H, CH₂), 3.03

2.26 (sept, 4H, J_HH7 Hz, CHMe₂), 1.24 (m, 12H, J_HH7 Hz,

3

(m, 4H, CH₂), 2.57 (m, 2H, NH), 2.23 (sept, 2H, J_HH7 Hz,

CHMe₂), 1.19 (m, 12H, J_HH7 Hz, CHMe₂), 0.52 (t, 3H, J_HP

CHMe₂), 2.12 (sept, 2H, ³J_HH7 Hz, CHMe₂), 1.31 (m, 6H, ³J_HH

7 Hz, PdMe). ¹³C{¹H} (CD₂Cl₂) 46.76 (vt, J_CP4 Hz, CH₂),

3

1

2

7 Hz, CHMe₂), 1.23 (m, 18H, J_HH7 Hz, CHMe₂), 0.19 (t, 3H,

38.33 (s, CH₂), 26.76 (vt, J_CP15 Hz, CHMe₂), 18.77 (vt, J_CP

³J_HP7 Hz, PdMe). ¹³C{¹H} (CD₂Cl₂) 54.49 (vt, J_CP2 Hz,

3 Hz, CHMe₂), 17.15 (s, CHMe₂), −6.00 (t, J_CP6 Hz, PdMe).

2

1

CH₂), 45.35 (vt, J_CP4 Hz, CH₂), 26.93 (vt, J_CP14 Hz,

CHMe₂), 26.68 (vt, J_CP14 Hz, CHMe₂), 19.03 (vt, J_CP3 Hz,

³¹P{¹H} (CD₂Cl₂) 81.65 (s). Anal. Calc. for C₁₇H₄₁IN₂P₂PdS:

C, 33.97; H, 6.88; N, 4.66; Found: C, 33.79; H, 6.77; N, 4.91.

1

2

CHMe₂), 18.87 (vt, J_CP3 Hz, CHMe₂), 17.61 (s, CHMe₂),

16.69 (s, CHMe₂), −13.02 (t, J_CP7 Hz, PdMe). ³¹P{¹H}

2

(CD₂Cl₂) 79.80 (s). Anal. Calc. for C₁₇H₄₂ClN₃P₂PdCl: C,

41.45; H, 8.60; N, 8.54; Found: C, 41.10; H, 8.63; N, 8.04.

9a: Starting with 2 (133 mg, 0.377 mmol) and (COD)PdMeCl

(100 mg, 0.377 mmol), the white product was obtained in

Synthesis of [κ³P,N,P-NH((CH₂)₂NHPiPr₂)₂PtMe]I (11),

[κ³P,S,P-S((CH₂)₂NHPiPr₂)₂PtMe]I (12)

These complexes were prepared in a similar fashion to 8b and

9b and thus only the amounts of starting materials are detailed.

1

89% yield (170 mg, 0.333 mmol). H (CD₂Cl₂) 3.73 (bt, 2H,

6794 | Dalton Trans., 2012, 41, 6791–6802

This journal is © The Royal Society of Chemistry 2012

View Online

11: Starting from 1 (54 mg, 0.161 mmol), (PPh₃)₄Pt (200 mg,

0.161 mmol) and iodomethane (23 mg, 0.161 mmol), the white

product was obtained in 86% yield (93 mg, 0.138 mmol).

¹H (CD₂Cl₂) 4.05 (bs, 1H, NH), 3.42 (m, 2H, CH₂), 3.34 (m,

4H, CH₂), 2.77 (m, 2H, CH₂), 2.67 (bt, 2H, NH), 2.35 (sept, 2H,

immediately giving a cloudy pale yellow mixture. The reaction

mixture was allowed to stir for 30 min at which point there was

no observable change. A suspension of NEt₃HCl (30 mg,

0.216 mmol) and THF (2 mL) was combined with the reaction

mixture giving a very pale yellow solution. The reaction

mixture was stirred for 12 hours at which point it was dried to a

pale-yellow solid. The crude product was washed with hexane

(3 × 4 mL) and the solution was decanted off before the product

was dried in vacuo. The white product was obtained in 93%

3

³J_HH7 Hz, CHMe₂), 2.25 (sept, 2H, J_HH7 Hz, CHMe₂), 1.32

(m, 6H, ³J_HH7 Hz, CHMe₂), 1.23 (m, 18H, ³J_HH7 Hz, CHMe₂),

3

2

0.38 (t, 3H, J_HP7 Hz, J_HPt76 Hz, PtMe). ¹³C{¹H} (CD₂Cl₂)

2

54.83 (vt, J_CP2 Hz, CH₂), 45.01 (vt, J_CP2 Hz, J_CPt37 Hz

CH₂), 27.04 (vt, J_CP18 Hz, CHMe₂), 26.48 (vt, J_CP18 Hz,

CHMe₂), 18.67 (vt, J_CP2 Hz, CHMe₂), 18.43 (vt, J_CP2 Hz,

1

yield (96 mg, 0.201 mmol). H (CD₂Cl₂) 5.47 (bs, 1H, NH),

2

3.68 (t, 2H, ³J_HH11 Hz, CH₂), 3.32 (m, 2H, CH₂), 3.01 (m, 2H,

3

CHMe₂), 17.57 (s, J_CPt23 Hz, CHMe₂), 16.63 (s, J_CPt21 Hz,

³J_HH11 Hz, CH₂), 2.69 (m, 2H, J_HH11 Hz, CH₂), 2.30 (bs,

CHMe₂), −27.19 (t, J_CP8 Hz, PtMe). ³¹P{¹H} (CD₂Cl₂)

2H, NHiPr), 1.94 (m, 2H, J_HH7 Hz, CHMe₂), 1.87 (m, 2H,

2

3

1

3

73.95 (t, J_PPt2842Hz). Anal. Calc. for C₁₇H₄₂N₃P₂PtI: C,

³J_HH1 Hz, CHMe₂), 1.20 (m, 12H, J_HH7 Hz, CHMe₂), 1.15

3

30.35; H, 6.30; N, 6.25; Found: C, 30.39; H, 6.50; N, 6.45.

12: Starting with 2 (57 mg, 0.161 mmol), (PPh₃)₄Pt (200 mg,

0.161 mmol), and CH₃I (23 mg, 0.161 mmol) the white solid

was obtained in a 77% yield (85 mg, 0.123 mmol). ¹H (CD₂Cl₂)

(m, 12H, J_HH7 Hz, CHMe₂), −13.24 (bt, 1H, PdH). ¹³C{¹H}

(CD₂Cl₂) 57.23 (vt, J_CP3 Hz, CH₂), 45.48 (vt, J_CP4 Hz, CH₂),

30.64 (vt, ¹J_CP13 Hz, CHMe₂), 27.86 (vt, ¹J_CP18 Hz, CHMe₂),

2

19.31 (bs, CHMe₂), 18.51 (bs, CHMe₂), 17.35 (vt, J_CP12 Hz,

3

3.42 (m, 4H, J_HH5 Hz CH₂), 3.25 (bt, 2H, NH), 3.00 (t, 4H,

CHMe₂). ³¹P{¹H} (CD₂Cl₂) 84.61 (s). Anal. Calc. for

C₁₆H₄₀ClN₃P₂Pd: C, 40.16; H, 8.43; N, 8.79; Found: C, 40.36;

H, 8.11; N, 8.79.

3

³J_HH5 Hz, S–CH₂), 2.39 (sept, 4H, J_HH7 Hz, CHMe₂), 1.24

3

(m, 12H, J_HH7 Hz, CHMe₂), 1.20 (m, 12H, J_HH7 Hz,

CHMe₂), 0.62 (t, 3H, J_HP7 Hz, J_HPt74 Hz, PtMe). ¹³C{¹H}

3

2

(CD₂Cl₂) 46.58 (t of vt, J_CP3 Hz, J_CPt51 Hz CH₂), 38.13

Synthesis of [κ³P,N,P-NH((CH₂)₂NHPiPr₂)₂PdH]PF₆(14b)

1

(t, J_CP7 Hz, CH₂), 26.53 (vt, J_CP18 Hz, CHMe₂), 18.34 (t of

2

vt, J_CP2 Hz, J_CPt15 Hz CHMe₂), 16.98 (s, J_CPt21 Hz,

A solid sample of NaPF₆(17.6 mg, 0.104 mmol) was added to a

colorless solution of 14a (50 mg, 0.104 mmol; 2 mL) giving a

cloudy mixture. The mixture was stirred over night and ﬁltered

through Celite to a clear colorless solution. The solution was

dried to a white solid. The product was obtained in 77% yield

(47 mg, 0.080 mmol). ¹H (CD₂Cl₂) 3.41 (m, 2H, CH₂), 3.32 (m,

2H, CH₂), 3.04 (m, 2H, CH₂), 2.79 (m, 3H, (2H) CH₂, (1H)

2

CHMe₂), −15.06 (t, J_CP8 Hz, PtMe). ³¹P{¹H} (CD₂Cl₂) 71.51

(t, ²J_PPt2707 Hz). Anal. Calc. for C₁₇H₄₁IN₂P₂PtS: C, 29.60; H,

6.00; N, 4.06; Found: C, 29.65; H, 6.10; N, 4.02.

Synthesis of [κ³P,N,P-HN(CH₂CH₂NHPiPr₂)₂NiH]PF₆(13b)

3

For this procedure the product from 13a was used without puriﬁ-

cation. To a stirring orange solution of 13a (50 mg, 0.116 mmol)

in CH₂Cl₂(2 mL) was added a suspension of NaPF₆in DCM

(20 mg, 0.116 mmol; 2 mL). The mixture was stirred for

12 hours yielding a slightly cloudy pale orange solution.

The reaction mixture was ﬁltered through Celite and dried to a

pale orange solid. The product was recrystallized from the diffu-

sion of diethyl ether into a CH₂Cl₂solution of the crude product.

13b was obtained as orange crystals in 71% yield (45 mg,

0.082 mmol). ¹H NMR (CD₂Cl₂) 3.33 (m, 4H, CH₂), 2.90

NH), 2.10 (bs, 2H, NHⁱPr), 1.92 (m, 4H, J_HH7 Hz, CHMe₂),

3

1.20 (m, 24H, J_HH7 Hz, CHMe₂), −13.42 (bt, 1H, PdH).

¹³C{¹H} (CD₂Cl₂) 58.14 (vt, J_CP3 Hz, CH₂), 46.28 (vt, J_CP

1

2

3 Hz, CH₂), 31.44 (vt, J_CP18 Hz, CHMe₂), 18.38 (vt, J_CP

2 Hz, CHMe₂), 17.22 (bs, CHMe₂), 17.09 (bs, CHMe₂). ¹⁹F

1

{¹H} (CD₂Cl₂) −74.07 (d, J_PF711 Hz). ³¹P{¹H} (CD₂Cl₂)

i

1

84.00 (s, Pr₂P), −144.47 (sept, J_PF711 Hz). Anal. Calc. for

C₁₆H₄₀N₃P₃PdF₆: C, 32.67; H, 6.86; N, 7.15; Found: C, 32.85;

H, 7.26; N, 7.21.

2

(m, 2H, CH₂), 2.79 (m, 2H, CH₂), 2.46 (bt, 1H, J_HH11.5 Hz,

Synthesis of [κ³P,S,P-S((CH₂)₂NHPiPr₂)₂PdH]PF₆(15)

3

NH), 1.84 (m, 6H, (4H) J_HH7.1 Hz, CHMe₂, (2H), NH),

3

2

1.21 (m, 24H, J_HH7.1 Hz, CHMe₂), −21.10 (t, J_HP80.7 Hz,

A solution of 2 (61 mg, 0.173 mmol) in THF (2 mL) was added

to a yellow slurry of Pd(PPh₃)₄(200 mg, 0.173 mmol) and THF

(2 mL) in a scintillation vial equipped with a stir bar. The reac-

tion mixture was allowed to stir for 30 min at which point there

was no observable change. A slurry of NH₄PF₆(28 mg,

0.173 mmol) and THF (2 mL) was combined with the reaction

mixture giving a white cloudy solution. The reaction mixture

was stirred for 12 hours at which point it was dried to a

pale-yellow solid. The crude product was washed with hexane

(3 × 4 mL) and the solution was decanted off before the product

was dried in vacuo. The solid was recrystallized from a mixture

of CH₂Cl₂, benzene and diethyl ether giving a white product in

79% yield (80 mg, 0.137 mmol). ¹H (CD₂Cl₂) 3.44 (m, 4H,

CH₂), 2.86 (m, 4H, CH₂), 2.22 (bs, 2H, NH), 2.00 (sept, 4H,

Ni–H). ¹³C{¹H} NMR (CD₂Cl₂) 56.91 (vt, J_CP4.4 Hz, CH₂),

44.91 (vt, J_CP3.7 Hz, CH₂), 30.45 (vt, J_CP15.4 Hz, CHMe₂),

1

2

27.99 (vt, J_CP20.6 Hz, CHMe₂), 19.14 (vt, J_CP2.2 Hz

CHMe₂), 18.52 (vt, ²J_CP2.2 Hz CHMe₂), 17.07 (s, CHMe₂). ¹⁹

F

{¹H} (CD₂Cl₂) −73.83 (d, J_FP711.4 Hz). ³¹P{¹H} (CD₂Cl₂)

1

79.28 (s), −144.42 (sept, J_PF711.4 Hz, PF₆). Anal. Calc. for

C₁₆H₄₀ClN₃P₃NiF₆: C, 35.56; H, 7.47; N, 7.78; Found: C,

35.70; H, 7.69; N, 7.80.

Synthesis of [κ³P,N,P-NH((CH₂)₂NHPiPr₂)₂PdH]Cl (14a)

A solution of 1 (81 mg, 0.216 mmol) in THF (2 mL) was added

to a bright yellow slurry of Pd(PPh₃)₄(250 mg, 0.216 mmol)

and THF (2 mL) in a scintillation vial equipped with a stir bar

3

³J_HH7 Hz, CHMe₂), 1.15 (m, 24H, J_HH7 Hz, CHMe₂),

This journal is © The Royal Society of Chemistry 2012

Dalton Trans., 2012, 41, 6791–6802 | 6795

View Online

3

−9.17 (bs, 1H, Pd–H). ¹³C{¹H} (CD₂Cl₂) 46.91 (vt, J_CP4 Hz,

CH₂), 3.00 (m, 4H, CH₂), 2.16 (sept, 4H, J_HH7 Hz, CHMe₂),

1

3

2

CH₂), 38.32 (vt, J_CP2 Hz, J_PtC13 Hz, CH₂), 29.66 (vt, J_CP

1.18 (m, 24H, J_HH7 Hz, CHMe₂), −10.11 (t of t, 1H, J_HP

2

1

16 Hz, CHMe₂), 18.73 (vt, J_CP4 Hz, CHMe₂), 17.06

16 Hz, J_HPt1221 Hz, Pt–H). ¹³C{¹H} (CD₂Cl₂) 46.84 (t of vt,

1

(s, CHMe₂). ¹⁹F {¹H} (CD₂Cl₂) −74.06 (d, J_PF710 Hz, PF₆).

J_CP3 Hz, J_PtC47 Hz, CH₂), 38.15 (t of vt, J_CP2 Hz, J_PtC14 Hz,

³¹P{¹H} (CD₂Cl₂) 89.25 (s), −144.24 (sept, J_PF710 Hz, PF₆).

CH₂), 30.32 (vt, ¹J_CP20 Hz, CHMe₂), 18.62 (t of vt, J_CP2 Hz,

1

2

3

Anal. Calc. for C₁₆H₃₉N₂P₃SPdF₆: C, 31.76; H, 6.50; N, 4.63;

Found: C, 32.22; H, 6.59; N, 4.73.

³J_PtC24 Hz, CHMe₂), 17 (d, J_PtC26 Hz, CHMe₂). ³¹P{¹H}

1

NMR (CD₂Cl₂) 79.48 (t, J_PPt2623 Hz). Anal. Calc. for

C₁₆H₃₉BrN₂P₂SPt: C, 30.56; H, 6.26; N, 4.46; Found: C, 31.02;

H, 6.29; N, 4.25.

Synthesis of [κ³P,N,P-NH((CH₂)₂NHPiPr₂)₂PtH]Cl (16a)

This complex was prepared in a similar fashion to 14a starting

with 1 (75 mg, 0.201 mmol), Pt(PPh₃)₄(250 mg, 0.201 mmol)

and NEt₃HCl (28 mg, 0.201 mmol). The pale-yellow product

Synthesis of [κ³P,S,P-S((CH₂)₂NHPiPr₂)₂PtH]PF₆(17b)

This complex was prepared in a similar fashion to 14a starting

with NaPF₆(13 mg, 0.080 mmol) and 17a (50 mg,

0.080 mmol). The product was obtained in 74% yield (41 mg,

1

was obtained in 90% yield (103 mg, 0.181 mmol). H (CD₂Cl₂)

3

6.24 (bs, 1H, NH), 3.79 (m, 2H, J_HH12 Hz, CH₂), 3.27 (m,

3

1

4H, CH₂NHP), 2.80 (m, 2H, J_HH11 Hz, CH₂), 2.35 (m, 2H,

0.059 mmol). H (CD₂Cl₂) 3.48 (m, 4H, CH₂), 3.25 (m, 2H,

NH), 2.04 (m, 2H, ³J_HH7 Hz, CHMe₂), 1.95 (m, 2H, ³J_HH7 Hz,

NH), 3.00 (m, 4H, CH₂), 2.13 (sept, 4H, J_HH7 Hz, CHMe₂),

3

2

CHMe₂), 1.21 (m, 12H, J_HH7 Hz, CHMe₂), 1.14 (m, 12H,

1.17 (m, 24H, J_HH7 Hz, CHMe₂), −10.10 (t of t, 1H, J_HP

³J_HH7 Hz, CHMe₂), −16.79 (tt, 1H, ²J_HP18 Hz, ¹J_HPt1025 Hz,

Pd–H). ¹³C{¹H} (CD₂Cl₂) 58.08 (vt, J_CP3 Hz, CH₂), 46.02 (vt,

16 Hz, J_HPt1216 Hz, Pt–H). ¹³C{¹H} (CD₂Cl₂) 46.92 (t of vt,

1

J

_CP3 Hz, J_PtC45 Hz, CH₂), 38.14 (t of vt, J_CP2 Hz, J_PtC14 Hz,

1

2

J_CP3 Hz, CH₂), 31.45 (vt, J_CP18 Hz, CHMe₂), 28.73 (vt, J_CP

CH₂), 30.34 (vt, ¹J_CP20 Hz, CHMe₂), 18.61 (t of vt, J_CP2 Hz,

2

23 Hz, CHMe₂), 19.13 (vt, J_CP2 Hz, CHMe₂), 18.41 (vt, J_CP

³J_PtC24 Hz, CHMe₂), 17.33 (d, ³J_PtC26 Hz, CHMe₂). ¹⁹F {¹H}

2

1

2 Hz, CHMe₂), 17.39 (d, J_CP12 Hz, CHMe₂). ³¹P{¹H}NMR

(CD₂Cl₂) −73.26 (d, J_PF711 Hz). ³¹P{¹H} (CD₂Cl₂) 79.82

1

(CD₂Cl₂) 79.92 (t, J_PPt2787 Hz). Anal. Calc. for

(t, J_PPt2637 Hz), −144.49 (sept, J_PF712 Hz). Anal. Calc.

for C₁₆H₃₉BrN₂P₃SPtF₆: C, 28.39; H, 5.96; N, 6.21; Found:

C, 28.53; H, 6.20; N, 6.12.

C₁₆H₄₀ClN₃P₂Pt: C, 33.87; H, 7.11; N, 7.41; Found: C, 33.39;

H, 6.96; N, 7.22.

Synthesis of [κ³P,N,P-NH((CH₂)₂NHPiPr₂)₂PtH]PF₆(16b)

Synthesis of 13a, 14a and 16a using 1HCl

This complex was prepared in a similar fashion to 14a starting

with NaPF₆(15 mg, 0.088 mmol) and 16a (50 mg,

0.088 mmol). The product was obtained in 80% yield (48 mg,

0.071 mmol). H (CD₂Cl₂) 3.39 (m, 5H, (4H) CH₂, (1H) NH),

3.24 (m, 2H, CH₂), 2.92 (m, 2H, CH₂), 2.30 (m, 2H, NH), 2.05

These complexes were prepared in a similar fashion and thus

only one preparation is detailed. 14a: A solution of 1HCl in

THF (81 mg, 0.216 mmol; 2 mL) was added to a bright yellow

slurry of Pd(PPh₃)₄and THF (250 mg, 0.216 mmol; 2 mL) in a

scintillation vial equipped with a stir bar immediately giving a

cloudy pale yellow mixture. The reaction mixture was stirred

for 2 hours at which point it was dried to a pale-yellow solid.

The crude product was washed with hexane (3 × 4 mL) and

the solution was decanted off before the product was dried

in vacuo. The white product was obtained in 93% yield (96 mg,

0.201 mmol).

(13a): Starting with 1HCl (68 mg, 0.182 mmol), (COD)₂Ni

(50 mg, 0.182 mmol), the orange product was obtained in 88%

yield (69 mg, 0.160 mmol).

(16a): Starting with 1HCl (75 mg, 0.201 mmol), (PPh₃)₄Pd

(100 mg, 0.173 mmol), the pale yellow product was obtained in

90% yield (103 mg, 0.181 mmol).

1

3

(m, 2H, J_HH7 Hz, CHMe₂), 1.99 (m, 2H, J_HH7 Hz, CHMe₂),

3

2

1.16 (m, 24H, J_HH7 Hz, CHMe₂), −17.21 (tt, 1H, J_HP18 Hz,

¹J_HPt1069 Hz, Pt–H). ¹³C{¹H} (CD₂Cl₂) 57.24 (vt, J_CP3 Hz,

1

CH₂), 45.82 (vt, J_CP4 Hz, CH₂), 30.65 (vt, J_CP13 Hz,

CHMe₂), 27.93 (vt, J_CP18 Hz, CHMe₂), 19.13 (vt, J_CP4 Hz,

1

2

CHMe₂), 18.49 (vt, J_CP4 Hz, CHMe₂), 17.25 (s, CHMe₂),

16.92 (s, CHMe₂). ¹⁹F {¹H} (CD₂Cl₂) −74.07 (d, J_PF712 Hz).

1

³¹P{¹H}NMR (CD₂Cl₂) 80.73 (t, ¹J_PPt2761 Hz), −144.49 (sept,

¹J_PF712 Hz). Anal. Calc. for C₁₆H₄₀N₃P₃PtF₆: C, 28.39; H,

5.96; N, 6.21; Found: C, 28.53; H, 6.20; N, 6.12.

Synthesis of [κ³P,S,P-S((CH₂)₂NHPiPr₂)₂PtH]Br (17a)

A solution of 2 in THF (71 mg, 0.201 mmol; 2 mL) was added

to a yellow-orange slurry of Pt(PPh₃)₄and THF (250 mg,

0.201 mmol; 2 mL) in a scintillation vial equipped with a stir

bar giving no immediate change. A slurry of PPh₃HBr and THF

(69 mg, 0.201 mmol; 2 mL) was then added and the mixture was

transferred to a bomb and heated for 12 h at 65 °C. The white

reaction mixture was dried to an off-white solid. The crude

product was washed with hexane (3 × 4 mL) and the solution

was decanted off before the product was dried in vacuo.

The white product was obtained in 83% yield (105 mg,

0.166 mmol). ¹H (CD₂Cl₂) 3.81 (m, 2H, NH), 3.49 (m, 4H,

Synthesis of [κ³P,N,P-NH((CH₂)₂NHPiPr₂)₂Pd(C₆H₄F)]Cl (19)

and [κ³P,S,P-S((CH₂)₂NHPiPr₂)₂Pd(C₆H₄F)]Cl (20)

These complexes were prepared in a similar fashion and thus

only one preparation is detailed. A solution of 1 (58 mg,

0.173 mmol) in THF (2 mL) was added to a yellow slurry of

Pd(PPh₃)₄(200 mg, 0.173 mmol) and THF (2 mL) in a scintil-

lation vial equipped with a stir bar. The reaction mixture was

allowed to stir for 30 min at which point a clear yellow solution

was obtained. A solution of o-ClFC₆H₄and THF (0.5 mL;

2 mL) was combined with the reaction mixture giving no

6796 | Dalton Trans., 2012, 41, 6791–6802

This journal is © The Royal Society of Chemistry 2012

View Online

immediate change. The reaction mixture was transferred to a

100 mL tube bomb and stirred for 12 hours at 65 °C at which

point it was dried to an orange solid. The crude product was

washed with hexane (3 × 4 mL) and the solution was decanted

off before the product was dried in vacuo. The off-white solid

was dissolved in CH₂Cl₂and benzene and diethyl ether were

layered on top of the CH₂Cl₂layer. The mixture was allowed to

slowly mix overnight giving colorless crystals and a pale-yellow

solution. The solution was decanted off and the crystals were

dried. The white product was obtained in 64% yield (63 mg,

0.110 mmol).

stream. The data were collected on a Bruker Apex II diffracto-

meter and data collection strategies were determined employing

Bruker provided Apex software. The data were collected at

150( 2) K for all crystals. Data reduction was performed using

the SAINT software package and an absorption correction

applied using SADABS. The structures were solved by direct

methods using XS and reﬁned by full-matrix least-squares on F²

using XL as implemented in the SHELXTL suite of programs.⁴⁰

All non-hydrogen atoms were reﬁned anisotropically. Carbon-

bound hydrogen atoms were placed in calculated positions using

an appropriate riding model and coupled isotropic temperature

factors.

1

19: H (CD₂Cl₂) 7.33 (m, 2H, ArH C₆, [a/b]), 7.00 (m, 2H,

ArH C₃, [a/b]), 6.93 (m, 2H, ArH C₅, [a/b]), 6.76 (m, 2H, ArH

C₄, [a/b]), 4.48 (bs, 1H, R₂NH [b]), 4.15 (bs, 1H, R₂NH [a]),

3.44 (m, 4H, CH₂[a/b]), 3.34 (m, 4H, CH₂[a/b]), 3.25 (s, 2H,

NH [a/b]), 3.14 (m, 2H, CH₂[a or b]), 3.09 (m, 2H, CH₂[a or

b]), 3.00 (s, 2H, NH [a/b]), 2.76 (m, 2H, CH₂[a or b]), 2.00

Results and discussion

A solution of 1 in CH₂Cl₂was added to a yellow suspension of

dmeNiCl₂in CH₂Cl₂giving a clear orange solution. After work-

up, 3a was obtained in 90% yield. The ³¹P{¹H} NMR spectrum

displayed a single resonance at 62.6 ppm, consistent with a

symmetric coordination of the phosphine donors. The solid

state structure was determined crystallographically (Fig. 1(a))

conﬁrming the pseudo-square planar geometry about the

Ni cation of formula [κ³P,N,P-NH((CH₂)₂NHPiPr₂)₂NiCl]Cl.

The P–Ni bond lengths are 2.2275(7) Å and 2.2529(7) Å, the

N–Ni bond length is 1.949(2) Å and the Ni–Cl bond length is

2.1664(7) Å. The P–Ni–P and N–Ni–Cl bond angles are 171.90

(2)° and 177.16(6)°, respectively, consistent with a slightly dis-

torted square planar geometry.

Complex 3a is only sparingly soluble in most solvents, and

thus halide exchange was used to improve solubility. The conver-

sion of 3a to [κ³P,N,P-NH((CH₂)₂NHPiPr₂)₂NiI]I (3b) was com-

pleted by the addition of two equivalents of Me₃SiI to a CH₂Cl₂

solution of 3a. A sharp color change from orange to purple is

observed, and 3b was obtained quantitatively following manipu-

lation. While the ¹H NMR spectrum remains similar to that

observed in 3a, aside from an up-ﬁeld shift of the central NH

proton resonance from 4.73 to 3.44 ppm, the ³¹P{¹H} signal is

shifted downﬁeld by 15.6 ppm to 78.2 ppm for 3b. This species

was also prepared directly in high yields from the reaction of 1

with NiI₂in CH₂Cl₂.

3

(m, 4H, J_HH6 Hz, CHMe₂[a/b]), 1.87 (m, 2H, J_HH6 Hz,

3

CHMe₂[a/b]), 1.78 (m, 2H, J_HH6 Hz, CHMe₂[a/b]), 1.30

3

(m, 12H, J_HH6 Hz, CHMe₂[a/b]), 1.19 (m, 12H, J_HH6 Hz,

3

CHMe₂[a/b]), 1.10 (m, 12H, J_HH6 Hz, CHMe₂[a/b]), 0.99

3

(m, 12H, J_HH6 Hz, CHMe₂[a/b]). ¹³C{¹H} (CD₂Cl₂) partial:

139.93 (d of t, J_CF16 Hz, J_CP2.44 Hz, Ar), 139.51 (d of t, J_CF

16 Hz, J_CP3 Hz, Ar), 126.05 (m, overlapping Ar), 124.33 (bs,

Ar), 124.10 (bs, Ar), 123.85 (m, C_ipso), 123.27 (m, C_ipso),

114.60 (m, overlapping Ar), 53.25 (m, CH₂obscured by

CH₂Cl₂), 52.79 (bs, CH₂), 44.81 (vt, J_CP3 Hz, CH₂), 44.29 (vt,

1

J_CP3 Hz, CH₂), 29.38 (vt, J_CP14 Hz, CHMe₂), 28.79 (vt, J_CP

15 Hz, CHMe₂), 28.08 (vt, ¹J_CP14 Hz, CHMe₂), 27.80 (vt, ¹J_CP

15 Hz, CHMe₂), 18.69 (bs, CHMe₂), 18.00 (bs, CHMe₂), 17.84

(bs, CHMe₂), 17.30 (bs, CHMe₂), 16.98 (bs, CHMe₂), 16.48 (bs,

CHMe₂), 15.94 (bs, CHMe₂). ¹⁹F {¹H} (CD₂Cl₂) −85.38 (t, ⁴J_FP

4

6 Hz, [b]), −85.85 (t, J_FP6 Hz, [a]). ³¹P{¹H} (CD₂Cl₂) 75.00

4

(d, J_PF6 Hz, [a]), 74.68 (d, J_PF6 Hz, [b]). Anal. Calc. for

C₂₂H₄₃N₃P₂PdClF: C, 46.14; H, 7.57; N, 7.34; Found: C, 45.94;

H, 7.62; N, 7.42.

20: Starting with 2 (61 mg, 0.173 mmol), (PPh₃)₄Pd (200 mg,

0.173 mmol), and o-ClFC₆H₄(0.5 mL) the white product was

1

obtained in 58% yield (59 mg, 0.100 mmol). H (CD₂Cl₂) 7.33

(m, 1H, ArH C₆), 7.04 (m, 1H, ³J_HH8 Hz, ArH C₃), 6.94 (t, 1H,

3

³J_HH7.82 Hz, ArH C₅), 6.77 (t, 1H, J_HH8 Hz, ArH C₄), 3.96

(bs, 2H, NH), 3.56 (m, 2H, CH₂), 3.33 (m, 2H, CH₂), 2.96 (m,

The analogous reaction of a CH₂Cl₂solution of 1 and a

yellow-orange suspension of (PhCN)₂PdCl₂afforded a clear

yellow solution which ultimately gave the product [κ³P,N,P-NH-

((CH₂)₂NHPiPr₂)₂PdCl]Cl (4a) in 94% yield. The ³¹P{¹H}

3

2H, CH₂), 2.73 (m, 2H, CH₂), 1.91 (m, 2H, J_HH8 Hz,

3

CHMe₂), 1.84 (m, 2H, J_HH8 Hz, CHMe₂), 1.21 (m, 6H, J_HH

8 Hz, CHMe₂), 1.11 (m, 12H, ³J_HH8 Hz, CHMe₂), 0.92 (m, 6H,

³J_HH8 Hz, CHMe₂). ¹³C{¹H} (CD₂Cl₂) 164.52 (d of t, ¹J_CF227

1

NMR spectrum shows a singlet at 71.6 ppm and the H NMR

3

Hz, J_CP3 Hz, ArC₂CF), 139.47 (d of t, J_CF17 Hz, J_CP3 Hz,

spectral data was consistent with a symmetrically bound triden-

tate ligand. X-ray quality crystals of 4a conﬁrmed the structure

(Fig. 1(b)). The two P–Pd, N–Pd and Pd–Cl bond lengths are

2.3172(19) Å and 2.3387(19) Å, 2.097(5) Å and 2.2913(17) Å,

respectively, while the N–Pd–Cl and P–Pd–P bond angles are

170.48(6)° and 177.1(2)° indicative of a distorted square

planar geometry. To improve solubility, the analogous [κ³P,N,

P-NH((CH₂)₂NHPiPr₂)₂PdI]I (4b) was prepared either quantita-

tively via the reaction of 4a with two equivalents of Me₃SiI or in

85% yield from the reaction of PdI₂with 1. While the major

spectroscopic characteristics of 4b are similar to 4a, the ³¹P{¹H}

2

ArC₆), 127.68 (d of t, J_CF42 Hz, J_CP10 Hz, ArC₁C–F),

126.72 (d of t, J_CF7 Hz, J_CP2 Hz, ArC₃), 124.68 (s, ArC₅),

114.73 (d, J_CF29 Hz, ArC₄), 46.24 (vt, J_CP3 Hz, CH₂), 37.55

(s, CH₂), 29.33 (vt, ¹J_CP15 Hz, CHMe₂), 28.52 (vt, ¹J_CP14 Hz,

CHMe₂), 18.89 (s, CHMe₂), 17.65 (m, CHMe₂), 17.57

(bs, CHMe₂), 16.40 (bs, CHMe₂). ¹⁹F {¹H} (CD₂Cl₂) −83.56

4

(t, J_FP5 Hz). ³¹P{¹H} (CD₂Cl₂) 74.55 (s). Anal. Calc. for

C₂₂H₄₂N₂P₂SPdClF: C, 44.81; H, 7.18; N, 4.75; Found: C,

44.66; H, 7.30; N, 5.01.

X-ray data collection, reduction, solution and reﬁnement

single crystals were coated in Paratone-N oil in the glovebox,

mounted on a MiTegen Micromount and placed under an N₂

1

NMR resonance of 4b is downﬁeld at 79.7 ppm while the H

resonance for the central NH shifts upﬁeld to 4.85 ppm.

Dalton Trans., 2012, 41, 6791–6802 | 6797

This journal is © The Royal Society of Chemistry 2012

Table 1 Crystallographic data

2a

3a

5a

6a

8a

9a

14b

16b

Formula

Form. wt

Cry. sys.

Space grp

a (Å)

b (Å)

c (Å)

C₁₆H₃₉Cl₂N₃NiP₂

465.05

C₁₆H₃₉Cl₂N₃P₂Pd

512.74

Orthorhombic

Pna2(1)

23.205(6)

10.981(2)

8.9992(19)

90.00

2293.2(9)

4

C₁₇H₄₀Cl₄N₂NiP₂S

567.02

C₁₇H₄₀Cl₄N₂P₂PdS

614.71

C₁₇H₄₂ClN₃P₂Pd

492.33

Monoclinic

C2/c

21.040(3)

8.6683(9)

27.228(3)

90.00

104.473(9)

90.00

4808.2(10)

8

C₁₈H₄₃Cl₃N₂P₂PdS

594.29

C₁₆H₃₉F₆N₃P₃Pd

586.81

Monoclinic

P2(1)/n

10.5371(4)

8.8800(4)

27.0360(9)

90.00

93.029(2)

90.00

2526.21(17)

4

C₁₆H₄₀F₆N₃P₃Pt

676.51

Triclinic

ˉ

P1

15.6535(9)

18.4051(10)

27.970(2)

104.784(3)

97.910(3)

109.773(2)

7106.6(8)

12

8.4687(10)

11.3598(13)

15.5241(18)

82.318(7)

74.896(7)

68.538(6)

1340.7(3)

2

8.4324(4)

11.4053(6)

15.4027(8)

81.069(2)

74.771(2)

68.760(2)

1329.25(12)

2

8.4214(15)

11.430(2)

15.337(3)

81.066(8)

74.944(8)

69.118(8)

1328.7(4)

2

10.4144(5)

10.5406(6)

12.3384(7)

84.575(2)

67.522(2)

88.505(2)

1245.85(12)

2

α (°)

β (°)

γ (°)

V (Å³)

Z

Temp (K)

d(calc) (g cm⁻¹

R(int)

150(2)

1.304

0.0409

1.184

150(2)

1.485

0.0686

1.187

150(2)

1.405

0.0627

1.327

150(2)

1.536

0.0287

1.307

150(2)

1.360

0.0506

1.021

150(2)

1.485

0.0349

1.207

150(2)

1.543

0.0281

0.976

150(2)

1.803

0.0240

5.877

)

μ (mm⁻¹

)

Total data

117 303

32 132

23 501

—

16 227

4271

3147

0.14(5)

217

15 080

4503

2723

—

22 016

6060

5230

—

21 062

5482

4002

—

21 331

6094

5046

—

17 068

4447

3948

—

17 256

4376

4217

—

# indpndt reﬂns

Reﬂns F₀> 2σ (F₀)

Flack param.

Variables

1297

244

256

217

244

262

266

R (>2σ)

0.0397

0.0998

1.013

0.0464

0.1001

1.047

0.0566

0.1568

1.049

0.0244

0.0577

1.019

0.0394

0.0845

1.028

0.0297

0.0710

1.019

0.0400

0.1033

1.026

0.0155

0.0358

1.039

R

_w(all data)

GOF

View Online

which adopted a square pyramidal geometry with a meridional

tridentate ligand and a chloride anion occupying the apical posi-

tion. This difference in complex geometry presumably results

from the more electron rich nature of the Ni-center in 5a com-

pared to that in κ³P,S,P-S((CH₂)₃PPh₂)₂NiCl₂reﬂecting the

strong donor ability of the dialkyl-aminophosphine ligand 2.

As with the formation of 3b, the synthesis of [κ³P,S,P-S-

((CH₂)₂NHPiPr₂)₂NiI]I (5b) was achieved either via direct reac-

tion of NiI₂and 2, or by reaction of 5a with Me₃SiI. Both pro-

cedures gave high yields. The ³¹P{¹H} NMR spectrum of 5b

showed a shift downﬁeld to 78.4 ppm upon replacement of the

halide with I.

The reaction of 2 with (PhCN)₂PdCl₂or PdI₂gives [κ³P,S,

P-S((CH₂)₂NHPiPr₂)₂PdCl]Cl (6a) and [κ³P,S,P-S((CH₂)₂NHPi-

Pr₂)₂PdI]I (6b), both as yellow solids, in high yields. In both

cases, the ³¹P{¹H} NMR spectrum shows a singlet, at 76.9 ppm

and 77.8 ppm, respectively, consistent with symmetric coordi-

nation of the ligand. The connectivity of 6a was further

conﬁrmed crystallographically, where again a square planar geo-

metry is observed with the P–Pd bond distances being 2.3316(5)

Å and 2.3476(5) Å, the S–Pd bond distance being 2.2963(5) Å,

and the Pd–Cl bond distance being 2.3089(5) Å (Fig. 2(b)).

Attempts to prepare Pt analogs via reactions of 1 and

(PhCN)₂PtCl₂or PtI₂in CH₂Cl₂gave only a mixture or impure

Fig. 1 POV-Ray depiction of the cations (a) 3a and (b) 4a: C: black,

N: aquamarine, P: orange, Cl: green, Ni: sky blue, Pd: lightwood.

Hydrogen atoms, except for NH, are omitted for clarity. Counter-ion also

omitted for clarity.

products. However the analogous reactions of

2 with

(PhCN)₂PtCl₂gave colorless solutions that after work-up yields

[κ³P,S,P-S((CH₂)₂NHPiPr₂)₂PtCl]Cl (7a) as a ﬂuffy white solid.

The ³¹P{¹H} NMR spectrum shows a singlet at 66.1 ppm with

1

Pt satellites showing a J_P–Ptcoupling constant of 2313 Hz.

Likewise, the reaction of

((CH₂)₂NHPiPr₂)₂PtI]I (7b) as an off-white solid that exhibits

2

with PtI₂gave [κ³P,S,P-S-

a

³¹P{¹H} resonance at 64.1 ppm with Pt satellites showing a

¹J_P–Ptof 2277 Hz.

Reaction of 1 or 2 with (COD)PdMeCl affords facile routes to

[κ³P,N,P-NH((CH₂)₂NHPiPr₂)₂PdMe]Cl (8a) and [κ³P,S,P-S-

((CH₂)₂NHPiPr₂)₂PdMe]Cl (9a) in high yields (Scheme 2). The

compounds 8a and 9a, both off-white solids, exhibited a single

resonance in the ³¹P{¹H} NMR spectra at 79.8 and 81.1 ppm,

respectively, as well as diagnostic upﬁeld triplets at 0.19 and

0.51 ppm in the ¹H NMR spectra, typical for the Pd–methyl

fragments.⁴²Both complexes were characterized crystallographi-

cally (Fig. 3). In 8a, the Pd–C, and Pd–P bond lengths are 2.065

(3) Å, 2.3168(9) Å and 2.3181(9) Å, respectively, while in 9a

the same analogous lengths are 2.071(3) Å, 2.3091(8) Å and

2.3230(7) Å, respectively. In both cases, the Pd–Me bond is

similar in length to that previously reported for κ³P,N,P-NH-

((CH₂)₂PiPr₂)PdMeCl (2.075 Å), and the P–Pd bond lengths in

8a and 9a are also similar to those reported for κ³P,N,P-NH-

((CH₂)₂PiPr₂)₂PdMeCl (2.2960–2.2970 Å).⁴²

Fig. 2 POV-Ray depiction of (a) 5a and (b) 6a: C: black, N: aqua-

marine, S: yellow, P: orange, Cl: green, Ni: sky blue, Pd: lightwood.

Hydrogen atoms except for NH are omitted for clarity. Counter-ion also

omitted for clarity.

Syntheses of analogous products incorporating the ligand

S((CH₂)₂NHPiPr₂)₂(2) were also undertaken. Reaction of 2 with

dmeNiCl₂in CH₂Cl₂gives a red-orange solution that upon

work-up yields [κ³P,S,P-S((CH₂)₂NHPiPr₂)₂NiCl]Cl (5a) as an

orange solid. The ³¹P{¹H} NMR spectrum shows a singlet at

1

68.5 ppm and the H NMR is consistent with the formulation.

The four coordinate geometry at the Ni center of the cation was

also conﬁrmed crystallographically (Fig. 2(a)). The P–Ni, S–Ni

and Ni–Cl bond lengths are 2.2371(16) Å and 2.2578(16) Å,

2.1702(18) Å and 2.1617(19) Å, respectively, while the S–Ni–Cl

and P–Ni–P bond angles are 168.48(8)° and 172.23(7)°, indica-

tive of a distorted square planar geometry.

Oxidative additions to give M-alkyl, hydride and aryl

derivatives

We have previously communicated the synthesis of [κ³P,N,P-

HN(CH₂CH₂NHPiPr₂)₂NiMe]I (10) from the reaction of

Ni(COD)₂, 1 and MeI in 79% yield.³⁹In a similar fashion, Pd–

alkyl analogues incorporating the ligands 1 or 2 were prepared

via the reaction with Pd(PPh₃)₄and MeI. Notably, there is no

The solid state structure of 5a stands in contrast to κ³P,S,P-S-

((CH₂)₃PPh₂)₂NiCl₂as previously reported by Cheng et al.⁴¹

Dalton Trans., 2012, 41, 6791–6802 | 6799

View Online

8b and 9b show singlets at 79.6 ppm and 81.7 ppm, respectively.

Both ¹H NMR and ¹³C{¹H} NMR spectra reveal diagnostic

upﬁeld resonances consistent with the presence of a Pd–Me frag-

ment (8b: ¹H: 0.22 ppm, ¹³C{¹H}: −12.66 ppm; 9b: ¹H:

0.52 ppm, ¹³C{¹H}: −6.00 ppm).⁴²

The analogous reactions were also carried out using Pt(PPh₃)₄

as a platinum source. The addition of a THF solution of 1 to an

off-white solution of Pt(PPh₃)₄gives no immediate change.

Upon addition of one equivalent of MeI, a white precipitate

formed. After work-up to remove free phosphine, [κ³P,N,P-NH-

((CH₂)₂NHPiPr₂)₂PtMe]I (11) was obtained in 86% yield.

The ³¹P{¹H} NMR spectrum contains a signal at 74.0 ppm with

1

Pt satellites having a J_Pt–Pcoupling constant of 2842 Hz.

1

The H NMR spectrum shows a triplet at 0.38 ppm with ¹⁹⁵Pt

satellite signals with P–H and Pt–H couplings of 7 Hz and

76 Hz, respectively. A diagnostic signal attributable to the metal-

bound carbon atom is observed in the ¹³C{¹H} spectrum at

−27.19 ppm with a C–P coupling constant of 8 Hz. Similarly,

the reaction of 2 with Pt(PPh₃)₄followed by the addition of MeI

results in the formation of [κ³P,S,P-S((CH₂)₂NHPiPr₂)₂PtMe]I

(12) as a white solid, which exhibits a ³¹P{¹H} signal centered

at 71.5 ppm with Pt-satellites and a Pt–P coupling constant of

2707 Hz. As was the case with 11, a triplet of triplets is observed

Fig. 3 POV-Ray depictions of (a) 8a and (b) 9a: C: black, N: aqua-

marine, S: yellow, P: orange, Cl: green, Pd: lightwood. Hydrogen atoms,

except for NH, are omitted for clarity. Counter-ion also omitted for

clarity.

1

in the H NMR at 0.62 ppm with the corresponding ¹³C reson-

ance at −15.06 ppm, conﬁrming the presence of the Pt–methyl

fragment.

We have also previously described the synthesis of analogous

Ni–hydride complexes employing a similar methodology.³⁹Thus,

oxidative addition reaction involving Ni(COD)₂, the ligand 1 and

NEt₃HCl afforded [κ³P,N,P-HN(CH₂CH₂NHPiPr₂)₂NiH]Cl (13a)

in 87% yield. The characteristic hydride triplet resonance was

1

seen in the H NMR spectrum at −20.90 ppm with P–H coup-

ling of 81 Hz while the ³¹P{¹H}NMR spectrum showed a

singlet at 80.00 ppm. Straightforward anion metathesis affords

[κ³P,N,P-HN(CH₂CH₂NHPiPr₂)₂NiH]PF₆(13b) as orange crys-

tals in 71% yield. The structure of 13b was previously described.

This same strategy can be employed to access Pd and Pt ana-

logues using Pd(PPh₃)₄and Pt(PPh₃)₄as synthons. In this

manner, [κ³P,N,P-NH((CH₂)₂NHPiPr₂)₂MH]X (M = Pd, X = Cl

14a, PF₆14b; M = Pt, X = Cl 16a, PF₆16b) and [κ³P,S,P-S-

((CH₂)₂NHPiPr₂)₂MH]X (M = Pd, X = PF₆15: M = Pt, X = Br

17a, PF₆17b) were prepared in yields ranging from 74–93%

yield. These species exhibit typical hydride resonance in

the range of −9 to −17 ppm. Compounds 14b and 16b were

crystallographically characterized (Fig. 4) conﬁrming the

pseudo-square planar geometry about the metals although the

hydride could not be found in 14b. In the case of 16b the Pt–H

bond length was found to be 1.693 Å, which is signiﬁcantly

elongated compared to that reported for trans-[(iPr₃P)₂Pt(H)-

(OEt₂)]⁺(1.53 Å).⁴⁴As all of these reactions required the use of

an external proton source, initial protonation of either 1 or 2

avoids the need for the additional reagent. Thus addition of a

solution of HCl in diethylether to a solution of 1 gave 1HCl as a

waxy solid. The most noticeable spectroscopic change was the

downﬁeld shift of the ³¹P{¹H} NMR singlet to 70.7 ppm. This

allowed for 13a, 14a, 16a to be prepared via the reactions

employing 1HCl and the appropriate metal (0) starting material.

In these cases the ligand itself acts as the proton source for

hydride formation.

Scheme 2 Synthesis of PNP and PSP Ni, Pd and Pt complexes.

reaction between 1 or 2 and Pd(PPh₃)₄, even with prolonged

heating. However, addition of MeI to solutions of 1 or 2 and Pd-

(PPh₃)₄in THF results in the in situ generation of (PPh₃)₂-

PdMeI⁴³which reacts with the tridentate ligands. Subsequent

work-up in both cases afforded white powders, [κ³P,N,P-HN-

(CH₂CH₂NHPiPr₂)₂PdMe]I (8b) and [κ³P,S,P-S(CH₂CH₂NHPi-

Pr₂)₂PdMe]I (9b), respectively. The ³¹P{¹H} NMR spectra for

6800 | Dalton Trans., 2012, 41, 6791–6802

View Online

length in 20 than that in 19, thus allowing free rotation about the

Pd–C bond. In addition, weaker donor from S in 20 presumably

facilitates inversion of the chiral S by a dissociation–re-associ-

ation mechanism.

Conclusion

In summary, we have described the syntheses and characterized

a series of Ni(^II), Pd(II) and Pt(II) complexes incorporating tri-

dentate bis-aminophosphine ligands. Employing an oxidative

addition strategy metal hydride, alkyl and aryl derivatives are

readily accessible. It is these latter species that are the subject of

on-going reactivity studies that will be reported in due course.

Acknowledgements

The authors thank NSERC of Canada for ﬁnancial support.

DWS is grateful for the award of a Canada Research Chair and a

Killam Research Fellowship. MJS is grateful for the award of an

NSERC-CGS.

Fig. 4 POV-Ray depictions of (a) 14b and (b) 16b; C: black, N: aqua-

marine, S: yellow, P: orange, Cl: green, Pd: lightwood. Pt: light steel

blue, Hydrogen atoms, except for NH and Pt–H, are omitted for clarity.

Counter-ion also omitted for clarity.

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Dalton Trans., 2012, 41, 6791–6802 | 6801

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6802 | Dalton Trans., 2012, 41, 6791–6802

Article Doi

Ni(II), Pd(II) and Pt(II) complexes of PNP and PSP tridentate amino-phosphine ligands

DOI: 10.1039/c2dt30373f

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Article abstract of DOI:10.1039/c2dt30373f

Full text of DOI:10.1039/c2dt30373f

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