Ruthenium complexes of phosphino derivatives of carboxylic amides: Synthesis and characterization of tridentate P,E2and tetradentate P,E3(E = N,O) ligands and their reactivity towards [RuCl2(PPh3)3]

Article abstract of DOI:10.1016/j.poly.2016.08.041

Neutral bi- and tripodal ligands of the type Ph_xP(L)_3?x(x = 1 (for 1), 0 (for 2); L = N-methylbenzamidyl (La, 1a, 2a), phthalimidyl (Lb, 1b, 2b), 2-pyridyloxy (Lc, 1c, 2c)) have been synthesized to act as P,O (1a, 1b, 2a,

Full text of DOI:10.1016/j.poly.2016.08.041

Polyhedron xxx (2016) xxx–xxx
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Polyhedron
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Ruthenium complexes of phosphino derivatives of carboxylic amides:
Synthesis and characterization of tridentate P,E2 and tetradentate
P,E3 (E = N,O) ligands and their reactivity towards [RuCl2(PPh3)3]
⇑
Robert Gericke, Jörg Wagler
Institut Für Anorganische Chemie, Technische Universität Bergakademie Freiberg, D-09596 Freiberg, Germany
a r t i c l e i n f o
a b s t r a c t
Article history:
Neutral bi- and tripodal ligands of the type PhxP(L)3ꢀx (x = 1 (for 1), 0 (for 2); L = N-methylbenzamidyl (La,
1a, 2a), phthalimidyl (Lb, 1b, 2b), 2-pyridyloxy (Lc, 1c, 2c)) have been synthesized to act as P,O (1a, 1b,
2a, 2b) or P,N (1c, 2c) chelating ligands in the ruthenium coordination sphere. Reactions of the ruthenium
source [RuCl2(PPh3)3] with 1a,b,c and 2b,c result in the formation of all-cis bis-chelate complexes
Received 5 July 2016
Accepted 22 August 2016
Available online xxxx
[RuCl2(PPh3)
during the reaction of [RuCl2(PPh3)3] with 2a a P–N bond cleavage in favor of P@O bond formation takes
place with formation of complex 5a [RuCl(PPh3)2 -P,O,O-(O@P(La)2)]. Treatment of the reaction mixture
with TlPF6 afforded the phosphonium salt 6 [Ph3P(Ph)C@NMe]PF6. Attempts to form similar compounds
to 5a with Lb or Lc (driven by chloride abstraction upon addition of TlPF6) only afforded the cationic
j-P,O,O- or j-P,N,N-(PhxP(L)3ꢀx)] 3a,b,c (x = 1) and 4b,c (x = 0), respectively. Surprisingly,
Keywords:
Ambidentate ligands
Chelates
NMR spectroscopy
Ruthenium
Single-crystal X-ray diffraction
j
complexes of the type [RuCl(PPh3)2j-P,O,O- or j-P,N,N-(P(L)3)]PF6 (L = Lb (7b), Lc (7c)). All isolated
compounds were characterized with multi-nuclear NMR spectroscopy, single-crystal X-ray diffraction
(except 4c) and elemental analysis.
Ó 2016 Elsevier Ltd. All rights reserved.
1. Introduction
[10–13]. For some other transition metals (TM) it has been shown
that tripodal ligands of the type PE3 with E = 2nd row elements can
Recently we reported the syntheses of diphenylphosphino func-
tionalized derivatives Ph2P-L of N-methylbenzamide (HLa),
phthalimidine (HLb) and pyridine-2-one (HLc) and we have shown
their P,O- (for L = La, Lb) or P,N-bidentate (for L = Lc) ligand behav-
ior towards ruthenium [1]. In analogy to these diphenylphosphino
form tripod complexes TM(j
4-PE3) as well (M,N,O) [14–16]. As
pointed out in our recent report [1], P,O ligands of the type N-phos-
phino functionalized carboxylic amide, we found a lack of litera-
ture reports for the coordination behavior towards the
catalytically highly active transition metal ruthenium, which
serves as a motivation for us to investigate this coordination chem-
istry for four related P,O ligands (bipodal 1a, 1b; tripodal 2a, 2b,
Scheme 2) and, for comparison, for two barely explored P,N ligands
(bipodal 1c, tripodal 2c) [8,17], which can be interpreted as
O-phosphino functionalized carboxylic amides.
functionalized
carboxy
amides,
we
synthesized
the
monophenylphosphino derivatives and the phosphino derivatives
(with PhPCl2 or PCl3 and a base, n-BuLi for reactions with HLa
and triethylamine for reactions with HLb and HLc). Similar series
of P,O-ambidentate phosphine functionalized amides PhxP(L)3ꢀx
(x = 2,1,0; L = 1,8-naphtholactamyl [2] (A), L = 3,3,4,4-tetramethyl-
succinimidyl [3] (B)) and of P,N-ambidentate ligands, such as PhxP
(L)3ꢀx with x = 2,1,0; L = ortho-N-methylanilinyl [4] (C) or L = 2-
picolyl [5–7] (D) are mentioned in the literature (Scheme 1). Those
and related bi-, tri- and tetradentate ligands show a high flexibility
in there coordination behavior towards transition metals [2,7–9]
(E–H). Whereas in H the basically tripodal PN3 ligand acts as a tri-
dentate chelator at ruthenium, tripodal PP03 ligands were shown to
form Ru-tripod complexes with hexacoordinated Ru atom (I,J,K,L)
2. Experimental
2.1. General considerations
All preparations were carried out under an atmosphere of dry
argon using standard Schlenk techniques. Phthalimidine [18] and
N-methylbenzamide [19] were prepared following literature meth-
ods. Tetrahydrofuran (THF) and triethylamine were distilled from
sodium/benzophenone and stored under dry argon. Dichloro-
methane (DCM) was distilled from calcium hydride and stored
under argon. Chloroform (stabilized with amylenes) was stored
⇑
Corresponding author. Fax: +49 3731 39 4058.
E-mail address: joerg.wagler@chemie.tu-freiberg.de (J. Wagler).
http://dx.doi.org/10.1016/j.poly.2016.08.041
0277-5387/Ó 2016 Elsevier Ltd. All rights reserved.
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R. Gericke, J. Wagler / Polyhedron xxx (2016) xxx–xxx
Scheme 1. Examples of neutral P,N and P,O ligands of the series PhxP(L)3ꢀx (x = 0, 1, 2) (A–D), examples of transition metal complexes using di-, tri- or tetradentate neutral P,N
and P,O chelating ligands (E–H), examples of tripodal RuP4 complexes (I–L) and examples of tripodal transition metal complexes with tripod arms out of 2nd row elements
(M–O).
Scheme 2. Synthesis of compounds 1a, 1b, 1c, 2a, 2b and 2c.
over molecular sieves 3 Å. [RuCl2(PPh3)3] was synthesized as
reported earlier [1]. All other chemicals used were commercially
available and were used without further purification. Elemental
microanalyses (C, H, N) were performed on a ‘Vario Micro Cube’
analyzer (Elementar, Hanau, Germany).
2.2. NMR spectroscopy
NMR spectra of solutions were recorded on an ‘Avance 500’ or
‘Ascend 400’ spectrometer (Bruker Biospin, Rheinstetten,
Germany) and internally referenced to tetramethylsilane for 1H
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R. Gericke, J. Wagler / Polyhedron xxx (2016) xxx–xxx
3
and 13C and externally referenced to 85% H3PO4 for 31P. Signals
were assigned by using 1H,1H-COSY, 1H,13C-HSQC, 1H,13C-HMBC
and 1H,1H-NOESY spectroscopy. Individual schemes for signal
assignment are provided with each complex (where applicable).
ppm): 4.72 (d, J = 17.11 Hz, –CH2–, 2H), 4.87 (d, J = 17.11 Hz, –CH2–,
2H), 7.39–7.50 (m, aryl, 7H), 7.53–7.62 (m, aryl, 4H), 7.84 (d,
J = 7.59 Hz, aryl, 2H). 13C{1H} NMR (CDCl3, d ppm): 52.90 (d,
J = 11.9 Hz), 123.6 (s), 124.8 (s), 128.5 (s), 129.3 (d, J = 5.7 Hz),
130.3 (s), 131.1 (d, J = 22.4 Hz), 132.0 (s), 133.1 (s), 134.1 (s),
144.8 (d, J = 6.0 Hz), 173.4 (d, J = 7.11 Hz). 31P{1H} NMR (CDCl3, d
ppm): 52.3 (s).
2.3. X-ray crystallography
1c: Synthesis of this compound was reported by Lindner et al.
with 70% yield [8]. We followed a slightly modified procedure (in
an analogous manner to our synthesis of 2c) from 2.00 g
(21.0 mmol) 2-hydroxypyridine, 4.65 g (21.0 mmol) triethylamine
and 1.89 g (10.5 mmol) dichlorophenylphosphine. The white crys-
talline product was obtained in 92% yield (2.86 g, 9.64 mmol).
Crystals suitable for single-crystal X-ray diffraction were obtained
by crystallization from hot n-hexane.
Single-crystal X-ray diffraction data sets were collected with
scans on an ‘IPDS-2(T)’ diffractometer (STOE, Darmstadt, Germany)
using Mo K -radiation. The absorption correction was performed
with XSHAPE using integration correction type. Structures were
solved by direct methods with SHELXS [20] and all non-hydrogen
atoms were anisotropically refined in full-matrix least-squares
cycles against |F2| (SHELXS) [21]. Hydrogen atoms were placed in ide-
alized positions and refined isotropically (riding model). Selected
parameters of data collection and refinement of the herein pre-
sented structures are listed in the Supporting information.
x-
a
Anal. Calc. for C16H13N2O2P (MW: 263.25), requires: C, 64.87; H,
4.42; N, 9.46. Found: C, 64.14; H, 4.69; N, 9.30%. 1H NMR (CDCl3, d
ppm): 6.90–7.00 (m, H3, H5, Lc, 4H), 7.48 (m, para-Ph, meta-Ph, 3H),
7.63 (m, H4, Lc, 2H), 7.97 (m, ortho-Ph, 2H), 8.14 (m, H6, Lc, 2H). 13
C
2.4. Syntheses of ligands 1a, 1b, 1c, 2a, 2b and 2c
{1H} NMR (CDCl3, d ppm): 112.6 (s, J = 1.48 Hz, C3, Lc), 118.6 (s, C5,
Lc), 128.4 (d, J = 7.27 Hz, meta-Ph), 130.4 (d, J = 26.11 Hz, ortho-Ph),
131.0 (s, para-Ph), 139.2 (s, C4, Lc), 140.5 (d, J = 18.23 Hz, ipso-Ph),
147.4 (s, C6, Lc), 161.8 (d, J = 6.67 Hz, C2, Lc). 31P{1H} NMR (CDCl3, d
ppm): 148.0 (s).
1a: N-Methylbenzamide (1.01 g, 7.50 mmol) was dissolved in
THF (20 mL) and cooled with an ice/ethanol mixture (to ca.
ꢀ10 °C). A solution of 2.5 M n-BuLi in hexanes (3 mL, 7.50 mmol)
was added dropwise. The white suspension was stirred with cool-
ing for 1.5 h and subsequently allowed to attain room temperature.
Dichlorophenylphosphine (671 mg, 3.75 mmol) was added with
stirring and the pale yellow suspension was stirred for 3 h at ambi-
ent temperature. Thereafter, the volatiles of the mixture were
evaporated (condensed into a cold trap under reduced pressure)
and the solid residue was dispersed in hot CHCl3 (20 mL) for
30 min. After cooling to room temperature the suspension was fil-
tered through Celite. From the filtrate the solvent was removed in
vacuo and the residue was recrystallized in THF (1.8 mL). The white
crystalline product was suitable for single-crystal X-ray diffraction.
The supernatant was removed by decantation, the white solid was
washed with 3 mL Et2O and dried in vacuo to yield 0.678 g
(1.69 mmol, 45%) of 1a. Although the crystal structure reveals the
formation of a THF solvate 1aꢁ0.75THF, the composition upon dry-
ing corresponds to the solvent free compound diluted by some
inert (non-C/H/N) material, which most likely is the byproduct LiCl.
Anal. Calc. for C22H21N2O2Pꢁ0.6LiCl (MW: 401.82), requires: C,
65.76; H, 5.27; N, 6.97. Found: C, 65.78; H, 5.28; N, 6.82%. 1H
NMR (CDCl3, d ppm): 3.12 (d, J = 0.67 Hz, -CH3, 6H), 7.16 (m, aryl,
4H), 7.23 (m, aryl, 4H), 7.27 (m, aryl, 2H), 7.41 (m, aryl, 2H), 7.49
(m, aryl, 1H), 7,55 (m, aryl, 2H). 13C{1H} NMR (CDCl3, d ppm):
33.7 (d, J = 6.5 Hz), 127.8 (d, J = 7.15 Hz), 127.9 (s), 129.6 (s),
129.7 (d, J = 22.5 Hz), 130.0 (d, J = 2.0 Hz), 130.2 (s), 133.7 (d,
J = 14.0 Hz), 135.8 (d, J = 3.2 Hz), 176.7 (d, J = 35.9 Hz). 31P{1H}
NMR (CDCl3, d ppm): 85.4 (s).
1b: Phthalimidine (800 mg, 6.01 mmol) was dissolved in THF
(40 mL). At ambient temperature triethylamine (670 mg,
6.62 mmol) was added dropwise and the mixture was stirred for
5 min, whereupon dichlorophenylphosphine (538 mg, 3.01 mmol)
was added and the mixture was stirred for one day. Thereafter the
white precipitate was filtered and washed with THF (3 mL). The
combined filtrate and washings were evaporated to dryness (con-
densation of volatiles into a cold trap under reduced pressure), the
residue was dissolved in THF (10 mL) and the solution was filtered
through Celite. After vapor diffusion of n-pentane into the filtrate
(for one week), white crystalline product suitable for single-crystal
X-ray diffraction was obtained. The supernatant was removed by
decantation, the white solid was washed with n-pentane (3 mL)
and dried in vacuo to yield 480 mg (1.29 mmol, 43%) of 1b.
2a: This compound was synthesized in an analogous manner to
1a from 900 mg (6.66 mmol) N-methylbenzamide, 2.7 mL
(6.75 mmol) of a 2.5 M n-BuLi solution in hexanes and 305 mg
(2.22 mmol) PCl3. The product was recrystallized from THF
(7 mL). The colorless crystalline product was obtained in 23% yield
(226 mg, 0.29 mmol).
Anal. Calc. for C24H24N3O3P (MW: 433.44), requires: C, 66.50; H,
5.58; N, 9.69. Found: C, 66.38; H, 5.72; N, 9.61%. 1H NMR (CDCl3, d
ppm): 3.18 (d, J = 1.15 Hz, –CH3, 9H), 7.00 (br. m, aryl, 6H), 7.26 (m,
aryl, 6H), 7.39 (m, aryl, 3H). 13C{1H} NMR (CDCl3, d ppm): 31.9 (s),
127.2 (d, J = 6.5 Hz), 128.3 (s), 130.5 (s), 135.4 (d, J = 3.2 Hz), 174.6
(d, J = 33.4 Hz). 31P{1H} NMR (CDCl3, d ppm): 93.9 (br. s).
2b: This compound was synthesized in an analogous manner to
1b from 800 mg (6.01 mmol) phthalimidine, 670 mg (6.62 mmol)
triethylamine and 275 mg (2.00 mmol) PCl3. The product was
recrystallized from THF (20 mL). The white crystalline product
was obtained in 43% yield (431 mg, 0.86 mmol).
Anal. Calc. for C24H18N3O3PꢁTHF (MW: 499.50), requires: C,
67.33; H, 5.25; N, 8.41. Found: C, 66.55; H, 5.25; N, 8.31%. 1H
NMR (CDCl3, d ppm): 4.89 (s, –CH2–, 6H), 7.47 (m, aryl, 6H), 7.60
(dd, J = 7.59 Hz, J = 7.13 Hz, aryl, 3H), 7.83 (d, J = 7.59 Hz, aryl,
3H). 13C{1H} NMR (CDCl3, d ppm): 51.2 (d, J = 8.6 Hz), 123.2 (s),
124.3 (s), 128.3 (s), 131.3 (s), 132.9 (s), 144.5 (d, J = 5.5 Hz), 172.8
(d, J = 11.5 Hz). 31P{1H} NMR (CDCl3, d ppm): 67.4 (s).
2c: Synthesis of this compound was reported by Weigand et al.
with 30% yield [17]. In an attempt at improving the yield we used a
modified procedure: To a solution of 2-hydroxypyridine (500 mg,
5.26 mmol) and triethylamine (532 mg, 5.26 mmol) in THF
(10 mL) at room temperature PCl3 (241 mg, 1.75 mmol) was added
with stirring. The white suspension was stirred at ambient temper-
ature for 3 h, then filtered and the white solid was washed with
THF (3 mL). The combined filtrate and washings were evaporated
to dryness (condensation of volatiles into a cold trap under
reduced pressure) and the residue was recrystallized from THF
(1 mL). After three weeks storage at ꢀ24 °C colorless crystals were
obtained. The supernatant was removed by decantation, the white
solid was washed with n-pentane (3 mL) and dried in vacuo. Yield:
286 mg (0.91 mmol, 52%). The compound is highly hygroscopic.
Anal. Calc. for C15H12N3O3Pꢁ1.3H2O (MW: 336.67), requires: C,
53.51; H, 4.37; N, 12.48. Found: C, 53.63; H, 4.54; N, 12.43%.
NMR data (1H, 13C, 31P) correspond to the data reported in [17].
Anal. Calc. for C22H17N2O2P (MW: 372.36), requires: C, 70.96; H,
4.60; N, 7.52. Found: C, 70.77; H, 4.67; N, 7.50%. 1H NMR (CDCl3, d
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R. Gericke, J. Wagler / Polyhedron xxx (2016) xxx–xxx
2.5. Syntheses of Ru-complexes 3a, 3b, 3c, 4b, 4c, 5a, 6, 7b and 7c
3.16%. 1H NMR (CDCl3, d ppm): 6.28 (ddd, J = 1.38 Hz, J = 6.13 Hz,
J = 7.46 Hz, H5B, 1H), 6.87 (d, J = 8.10 Hz, H3B, 1H), 6.90–6.98 (m,
3a: 1a (91 mg, 226
lmol) and [RuCl2(PPh3)3] (219 mg,
meta-PPh3, 6H), 7.00–7.09 (m, para-PPh3, H3A, 4H), 7.11 (m, H5A
,
228 mol) were dissolved in CHCl3 (3 mL). The deep red solution
l
1H), 7.27–7.34 (m, meta-PPh, H4B, 3H), 7.52 (t, J = 7.61 Hz, para-
was stirred at room temperature for 10 min. After vapor diffusion
of Et2O (for one week) and formation of crystalline material during
that time, the supernatant was removed by decantation, the crude
yellow solid was dispersed in 10 mL CHCl3, filtered, washed with
PPh, 1H), 7.59–7.69 (m, ortho-PPh3, H4A, 7H), 7.75 (m, ortho-PPh,
2H), 8.80 (dd, J = 1.69 Hz, J = 6.13 Hz, H6B, 1H), 9.78 (br. m, H6A
,
1H). 13C{1H} NMR (CDCl3, d ppm): 109.8 (d, J = 7.13 Hz, C3B),
110.5 (d, J = 6.29 Hz, C3A), 118.9 (s, C5B), 120.0 (d, J = 2.74 Hz,
C5A), 127.3 (d, J = 9.65 Hz, meta-PPh3), 128.7 (d, J = 12.37 Hz,
meta-PPh), 128.8 (d, J = 2.15 Hz, para-PPh3), 130.6 (d, J = 78.9 Hz,
ipso-PPh), 130.8 (d, J = 12.84 Hz, ortho-PPh), 132.3 (d, J = 1.41 Hz,
para-PPh), 133.5 (d, J = 9.41 Hz, ortho-PPh3), 133.6 (d, J = 45.0 Hz,
ipso-PPh3), 137.8 (s, C4B), 140.1 (s, C4A), 149.9 (s, C6A), 152.6 (s,
C6B), 161.7 (m, C2A), 162.4 (d, J = 2.27 Hz, C2B). 31P{1H} NMR (CDCl3,
d ppm): 210.7 (d, J = 37.2 Hz, PhP(Lc)2, 1P), 41.0 (d, J = 37.2 Hz,
PPh3, 1P).
CHCl3 (1 mL) and dried in vacuo. Yield: 44 mg (46 lmol, 20%). Yel-
low crystals, suitable for single-crystal X-ray diffraction, were
obtained by vapor diffusion of Et2O into a CH2Cl2 solution within
one week. Although the crystal structure reveals the formation of
a dichloromethane solvate 3aꢁ3CH2Cl2, the elemental composition
upon drying corresponds to lower solvent content.
Anal. Calc. for
C
40H36Cl2N2O2P2Ruꢁ1.2CHCl3 (MW: 953.90),
requires: C, 51.88; H, 3.93; N, 2.94. Found: C, 51.87; H, 4.12; N,
2.81%. 1H NMR (CD2Cl2, d ppm): 3.28 (d, J = 4.64 Hz, –CH3, 3H),
3.30 (d, J = 4.45 Hz, –CH3, 3H), 6.95–7.01 (m, aryl, 6H), 7.02–7.09
(m, aryl, 5H), 7.32–7.38 (m, aryl, 2H), 7.43–7.50 (m, aryl, 3H),
7.51–7.66 (br. m, aryl, 14H). 13C{1H} NMR (CD2Cl2, d ppm): 38.2
(d, J = 3.98 Hz, -CH3), 38.9 (d, J = 4.55 Hz, -CH3), 126.3 (d,
J = 62.51 Hz, ipso-PPh), 127.6 (d, J = 9.85 Hz, meta-PPh3), 127.9 (s),
128.4 (s), 128.9 (s), 129.1 (s), 129.2 (d, J = 2.08 Hz, para-PPh3),
130.4 (d, J = 11.36 Hz), 130.7 (d, J = 5.68 Hz), 131.6 (d,
J = 12.18 Hz), 131.8 (s), 132.4 (s), 133.2 (s), 133.4 (m), 134.1 (d,
J = 9.63 Hz, ortho-PPh3), 134.4 (d, J = 47.73 Hz, ipso-PPh3), 184.7
(m), 184.8 (m). 31P{1H} NMR (CD2Cl2, d ppm): 166.6 (d, J = 38 Hz,
PhP(La)2, 1P), 54.1 (d, J = 38 Hz, PPh3, 1P).
4b: This compound was synthesized in an analogous manner to
3c from 65 mg (130
PPh3)3] in 10 mL CH2Cl2. The orange crystalline product was
obtained in 76% yield (92 mg, 99 mol). Although the crystal struc-
lmol) 2b and 125 mg (130 lmol) [RuCl2(-
l
ture reveals the formation of a dichloromethane solvate 4bꢁ2CH2-
Cl2, the elemental composition upon drying corresponds to lower
solvent content.
Cl
Cl
O
PPh3
O
Ru
P
4
7
3
3a
7a
5
6
N
1
N
N
A
B
O
3b: 1b (210 mg, 564
lmol) and [RuCl2(PPh3)3] (540 mg,
N
O
563 mol) were dissolved in CHCl3 (30 mL). The red solution was
l
stirred for 2 h at room temperature to form an orange suspension,
C
which was then filtered, the orange solid was washed with CHCl3
(2 mL) and dried in vacuo. Yield: 310 mg (326 lmol, 58%). Orange
crystals, suitable for single-crystal X-ray diffraction, were obtained
by vapor diffusion of Et2O into a CHCl3 solution. Although the crys-
Anal. Calc. for C42H33Cl2N3O3P2RuꢁCH2Cl2 (MW: 946.58),
requires: C, 54.56; H, 3.73; N, 4.44. Found: C, 54.34; H, 3.56; N,
4.47%. 1H NMR (CDCl3, d ppm): 4.45 (d, J = 17.20 Hz, H3C, 1H),
4.84 (m, H3A/C, 2H), 4.97 (d, J = 16.62 Hz, H3A, 1H), 5.10 (d,
J = 17.37 Hz, H3B, 1H), 5.40 (d, J = 17.37 Hz, H3B, 1H), 6.91–7.01
(m, meta-PPh3, para-PPh3, 9H), 7.19 (d, J = 7.75 Hz, H7B, 1H), 7.27
(m, H6B, 1H), 7.32 (d, J = 7.60 Hz, H4C, 1H), 7.36 (d, J = 7.75 Hz,
tal structure reveals the formation of
a chloroform solvate
3bꢁ1.95CHCl3, the elemental composition upon drying corresponds
to lower solvent content.
Anal. Calc. for
C
40H32Cl2N2O2P2Ruꢁ1.2CHCl3 (MW: 949.87),
H4B, 1H), 7.42 (d, J = 7.55 Hz, H4A, 1H), 7.50 (m, H6A, H5B, H6C
3H), 7.58 (dd, J = 7.55 Hz, J = 8.16 Hz, H5A, 1H), 7.66 (m, H5C, H7C
,
,
requires: C, 52.10; H, 3.52; N, 2.95. Found: C, 52.23; H, 3.37; N,
3.09%. 1H NMR (CD2Cl2, d ppm): 4.51 (d, J = 17.12 Hz, –CH2–, 2H),
4.90 (d, J = 17.12 Hz, –CH2–, 1H), 4.99 (d, J = 17.12 Hz, –CH2–,
1H), 6.98 (m, aryl, 6H), 7.05 (m, aryl, 3H), 7.28–7.39 (br. m, aryl,
CHCl3, 3.2H), 7.44 (m, aryl, 4H), 7.50–7.73 (br. m, aryl, 12H), 8.16
(d, J = 7.69 Hz, aryl, 1H). 31P{1H} NMR (CD2Cl2, d ppm): 127.2 (d,
J = 43.5 Hz, PhP(Lb)2, 1P), 57.0 (d, J = 43.5 Hz, PPh3, 1P).
2H), 7.90 (m, ortho-PPh3, 6H), 8.13 (d, J = 7.76 Hz, H7A, 1H). 13C
{1H} NMR (CDCl3, d ppm): 50.3 (m, C3A), 51.4 (d, J = 14.5 Hz, C3C),
53.0 (m, C3B), 123.2 (s, C4C), 123.3 (s, C4B), 123.5 (s, C4A), 124.7 (s,
C7C), 125.2 (s, C7B), 126.1 (m, C7aB), 126.3 (s, C7A), 127.5 (d,
J = 10.1 Hz, meta-PPh3), 128.1 (s, C6B), 128.4 (s, C6C), 129.2 (s, C6A
,
para-PPh3), 130.0 (m, C7aC), 132.1 (m, C7aA), 133.5–134.4 (br. m,
C5A, C5B, C5C, ipso-PPh3, ortho-PPh3), 144.4 (m, C3aC), 146.0 (s,
C3aA), 146.8 (s, C3aB), 171.1 (s, C1C), 180.8 (m, C1A), 183.1 (d,
3c: 1c (154 mg, 519
lmol) and [RuCl2(PPh3)3] (498 mg,
519 mol) were dissolved in CHCl3 (3 mL). The orange solution
l
was stirred for 10 min at room temperature and then filtered
through Celite. After four days, orange crystals, suitable for sin-
gle-crystal X-ray diffraction, were obtained by vapor diffusion of
Et2O into the filtrate. The supernatant was decanted, the solid
was washed with Et2O (2 mL) and dried in vacuo. Yield: 312 mg
J = 19.3 Hz, C1B). 31P{1H} NMR (CDCl3,
d ppm): 123.6 (d,
J = 48.9 Hz, P(Lb)3, 1P), 52.6 (d, J = 48.9 Hz, PPh3, 1P).
4c: This compound was synthesized in an analogous manner to
3c from 156 mg (498
PPh3)3] in 10 mL CHCl3. The yellow fine crystalline product was
obtained in 69% yield (285 mg, 345 mol). The presence of the sol-
lmol) 2c and 478 mg (498 lmol) [RuCl2(-
(343 lmol, 66%).
l
Cl
Ru
P
vents used to interpret the elemental composition was confirmed
Cl
N
PPh3
by 1H NMR spectroscopy.
4
5
6
3
N
B
A
Cl
O
O
Cl
2
N
O
PPh3
Ru
4
N
N
5
6
3
C
A
P
O
O
2
N
O
O
N
B
Anal. Calc. for C34H28Cl2N2O2P2Ruꢁ1.5CHCl3 (MW: 909.59),
requires: C, 46.88; H, 3.27; N, 3.08. Found: C, 46.96; H, 3.29; N,
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R. Gericke, J. Wagler / Polyhedron xxx (2016) xxx–xxx
5
Anal. Calc. for C33H27Cl2N3O3P2Ruꢁ0.4CHCl3ꢁ0.4Et2O (MW:
Cl
Ru
P
824.91), requires: C, 50.96; H, 3.84; N, 5.09. Found: C, 50.98; H,
Ph3P
O
PPh3
O
3.81; N, 5.10%. 1H NMR (CDCl3, d ppm): 6.33 (dd, J = 6.15 Hz,
J = 7.63 Hz, H5C, 1H), 6.74 (d, J = 7.99 Hz, H3C, 1H), 7.02 (m, H3A
,
4
7
3
PF6
3a
7a
meta-PPh3, 7H), 7.13 (m, H5A
, para-PPh3, 4H), 7.19 (dd,
5
6
N
N
N
1
J = 4.87 Hz, J = 6.83 Hz, H5B, 1H), 7.30 (m, H4C, 1H), 7.31 (m, H3B
,
A
A
N
O
1H), 7.69 (dd, J = 7.70 Hz, J = 8.43 Hz, H4A, 1H), 7.76 (m, H4B, 1H),
7.80 (dd, J = 8.84 Hz, J = 10.89 Hz, ortho-PPh3, 6H), 8.29 (dd,
O
B
J = 4.87 Hz, H6B, 1H), 8.89 (dd, J = 6.15 Hz, H6C, 1H), 9.66 (m, H6A
,
1H). 13C{1H} NMR (CDCl3, d ppm): 109.8 (d, J = 8.34 Hz, C3C),
110.5 (d, J = 7.30 Hz, C3A), 114.0 (d, J = 4.35 Hz, C3B), 118.8 (s, C5C),
120.0 (d, J = 2.0 Hz, C5A), 121.1 (s, C5B), 127.6 (d, J = 9.56 Hz, meta-
PPh3), 129.1 (d, J = 1.67 Hz, para-PPh3), 133.8 (d, J = 9.60 Hz,
ortho-PPh3), 134.0 (d, J = 43 Hz, ipso-PPh3), 138.3 (s, C4C), 140.2 (s,
C4B), 140.6 (s, C4A), 147.9 (s, C6B), 150.0 (s, C6A), 152.4 (s, C6C),
157.4 (d, J = 6.75 Hz, C2B), 160.7 (d, J = 6.41 Hz, C2A), 160.9 (d,
Anal. Calc. for C60H48ClF6N3O3P4RuꢁCHCl3ꢁ0.25Et2O (MW:
1371.36), requires: C, 54.30; H, 3.79; N, 3.06. Found: C, 54.60; H,
3.81; N, 3.22%. 1H NMR (CDCl3, d ppm): 3.46 (m, H3B, 2H), 4.96
(d, J = 17.94 Hz, H3A, 2H), 5.09 (d, J = 17.94 Hz, H3A, 2H), 6.99 (dd,
J = 7.42 Hz, J = 7.75 Hz, meta-PPh3, 12H), 7.13 (t, J = 7.42 Hz, para-
PPh3, 6H), 7.29 (d, J = 7.70 Hz, H4B, 1H), 7.36 (dd, J = 7.65 Hz,
J = 7.45 Hz, H6A, 2H), 7.45 (m, H7B, 1H), 7.48 (m, H6B, H7A, 3H),
7.54 (d, J = 7.70 Hz, H4A, 2H), 7.59 (m, H5A, ortho-PPh3, 14H), 7.72
(m, H5B, 1H). 13C{1H} NMR (CDCl3, d ppm): 49.7 (d, J = 7.0 Hz,
C3B), 52.5 (d, J = 6.1 Hz, C3A), 123.4 (s, C4B), 124.5 (s, C4A), 124.8
(s, C7B), 125.2 (s, C7A), 125.8 (d, J = 4.0 Hz, C7aA), 127.8 (m, meta-
PPh3), 128.5 (s, C6A), 128.7 (s, C6B), 129.2 (d, J = 5.3 Hz, C7aB),
J = 6.58 Hz, C2C). 31P{1H} NMR (CDCl3,
d ppm): 166.4 (d,
J = 51.1 Hz, P(Lc)3, 1P), 41.7 (d, J = 51.1 Hz, PPh3, 1P).
5a: 2a (500 mg, 1.15 mmol) and [RuCl2(PPh3)3] (1.11 g,
1.15 mmol) were dissolved in THF (5 mL) and heated under reflux
for 3 h. During that time yellow solid precipitated. After cooling to
room temperature the suspension was filtered and the yellow solid
was washed with THF (2 ꢂ 2 mL) and dried in vacuo. Yield: 53%
130.2 (s, para-PPh3), 133.6 (br. m, ipso-PPh3), 134.7 (m, C5B
,
ortho-PPh3), 135.0 (m, C5A), 143.5 (d, J = 8.5 Hz, C3aB), 147.7 (s,
C3aA), 171.0 (s, C1B), 182.5 (d, J = 18.0 Hz, C1A). 31P{1H} NMR (CDCl3,
d ppm): 128.0 (t, J = 39.0 Hz, P(Lb)3, 1P), 40.4 (d, J = 39.0 Hz, PPh3,
2P), ꢀ144.3 (sept., J = 713 Hz, PFꢀ6 , 1P).
(646 mg, 616 lmol). Crystals of 5a, suitable for single-crystal X-
ray diffraction, were obtained by recrystallization in THF. Although
the crystal structure reveals the formation of a THF solvate
5aꢁ3THF, the elemental composition upon drying corresponds to
lower solvent content.
7c: This compound was synthesized in an analogous manner to
7b from 110 mg (351
and 300 mg (859 mol) TlPF6 in 10 mL CHCl3. The yellow crys-
talline product was obtained in 75% yield (324 mg, 263 mol).
lmol) 2c, 337 mg (351 lmol) [RuCl2(PPh3)3]
Anal. Calc. for C52H46ClN2O3P3RuꢁTHF (MW: 1048.48), requires:
C, 64.15; H, 5.19; N, 2.67. Found: C, 63.90; H, 5.09; N, 2.35%. 1H
NMR (CDCl3, d ppm): 2.90 (d, J = 3.80 Hz, –CH3, 6H), 6.93 (m,
ortho-Ph, 4H), 7.08 (dd, J = 7.60 Hz, J = 8.19 Hz, meta-PPh3, 12H),
7.20 (m, meta-Ph, para-PPh3, 10H), 7.33 (tm, J = 7.51 Hz, para-Ph,
2H), 7.54 (m, ortho-PPh3, 12H). 13C{1H} NMR (CDCl3, d ppm): 32.6
(s, –CH3), 127.2 (dd, J = 5.77 Hz, J = 4.59 Hz, meta-PPh3), 127.8 (s,
meta-Ph), 128.3 (s, ortho-Ph), 129.0 (s, para-PPh3), 130.9 (s, para-
Ph), 132.2 (s, ipso-Ph), 134.5 (m, ipso-PPh3), 135.1 (dd, J = 5.83 Hz,
J = 4.71 Hz, ortho-PPh3), 177.8 (d, J = 11.81 Hz, NCO). 31P{1H} NMR
l
l
Although the crystal structure reveals the formation of a chloro-
form solvate 7cꢁCHCl3, the elemental composition of the bulk
material indicates mixed solvates of chloroform and diethyl ether.
Cl
Ph3P
PPh3
4
Ru
5
6
3
N
A
N
A
PF6
P
2
N
O
O
O
O
N
B
(CDCl3,
d ppm): 142.8 (t, J = 44.3 Hz, OP(La)2, 1P), 47.2 (d,
J = 44.3 Hz, PPh3, 2P).
The combined filtrated and washings were treated with TlPF6
(403 mg, 1.15 mmol) and stirred at room temperature for 3 h.
The suspension was filtered through Celite and the filtrate was
evaporated to dryness under reduced pressure. Attempts to isolate
6 in pure state from this residue, i.e., by recrystallization from
CHCl3 or THF solutions upon vapor diffusion of Et2O, failed. How-
ever, a small amount of crystals of 6, suitable for single-crystal
X-ray diffraction, were obtained by vapor diffusion of Et2O into a
CHCl3 solution of the crude reaction mixture of [RuCl2(PPh3)3], 2a
and TlPF6.
Anal. Calc. for C51H42ClF6N3O3P4Ruꢁ0.8CHCl3ꢁ0.2Et2O (MW:
1229.63), requires: C, 51.38; H, 3.67; N, 3.42. Found: C, 51.52; H,
3.59; N, 3.46%. 1H NMR (CD2Cl2, d ppm): 6.77 (m, H3A, H5A, 4H),
7.03 (d, J = 8.12 Hz, H3B, 1H), 7.09 (dd, J = 7.50 Hz, J = 8.02 Hz,
meta-PPh3, 12H), 7.30 (t, J = 7.50 Hz, para-PPh3, CHCl3, 6.8H), 7.39
(m, ortho-PPh3, 12H), 7.48 (ddd, J = 7.34 Hz, J = 4.88 Hz,
J = 0.75 Hz, H5B, 1H), 7.53 (ddd, J = 7.83 Hz, J = 7.76 Hz, J = 1.43 Hz,
H4A, 2H), 8.01 (ddd, J = 8.12 Hz, J = 7.34 Hz, J = 2.04 Hz, H4B, 1H),
8.55 (ddd, J = 4.88 Hz, J = 2.04 Hz, J = 0.60 Hz, H6B, 1H), 8.92 (dm,
J = 6.03 Hz, H6A, 2H). 13C{1H} NMR (CD2Cl2, d ppm): 112.2 (d,
J = 7.84 Hz, C3A), 115.0 (d, J = 3.22 Hz, C3B), 121.3 (s, C5A), 123.7 (s,
C5B), 128.3 (dd, J = 5.66 Hz, J = 4.80 Hz, meta-PPh3), 130.7 (s, para-
PPh3), 132.6 (m, ipso-PPh3), 135.0 (dd, J = 5.60 Hz, J = 4.75 Hz,
ortho-PPh3), 141.6 (s, C4B), 142.2 (s, C4A), 148.9 (s, C6A), 149.1 (s,
C6B), 157.3 (s, J = 22.53 Hz, C2B), 160.4 (s, J = 5.37 Hz, C2A). 31P{1H}
NMR (CD2Cl2, d ppm): 162.6 (t, J = 48 Hz, P(Lc)3, 1P), 36.4 (d,
J = 48 Hz, PPh3, 2P), ꢀ144.5 (sept., J = 713 Hz, PFꢀ6 , 1P).
31P{1H} NMR (CDCl3, d ppm): 15.1 (s, Ph3P(Ph)C = NMe+, 1P),
ꢀ144.5 (sept., J = 713 Hz, PFꢀ6 , 1P).
7b: 2b (69 mg, 138
138
was stirred for 15 min at room temperature, whereupon solid TlPF6
(98 mg, 281 mol) was added and the yellow suspension was stir-
lmol) and [RuCl2(PPh3)3] (132 mg,
l
mol) were dissolved in CHCl3 (10 mL). The orange solution
l
red at room temperature for 1 h and then filtered through Celite.
After four days, yellow crystals, suitable for single-crystal X-ray
diffraction, were obtained by vapor diffusion of Et2O into the fil-
trate. The supernatant was decanted, the solid was washed with
3. Results and discussion
Et2O (3 mL) and dried in vacuo. Yield: 107 mg (78 lmol, 57%).
3.1. Chelating ligands
Although the crystal structure reveals the formation of a solvate
7bꢁCHCl3ꢁ2Et2O, the elemental composition upon drying corre-
sponds to lower diethyl ether content.
The reaction of PhPCl2 or PCl3 with the lithium salt of N-methyl-
benzamide (HLa) or, in presence of triethylamine, with phthalim-
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6
R. Gericke, J. Wagler / Polyhedron xxx (2016) xxx–xxx
idine (HLb) or 2-hydroxypyridine (HLc) gave the N-substituted
derivatives 1a, 2a, 1b and 2b and the expected O-substituted
derivatives 1c and 2c in an analogous manner to their
diphenylphosphino-functionalized homologs (Scheme 2) [1]. As
reported for the PPh2 derivatives [1], in the 13C{1H} NMR spectrum
we observed the characteristic 2JP,C coupling of the carbon atoms in
direct contiguity of the N atoms for 1a, 2a, 1b and 2b, supporting
the N-P bonding situation, and of the carbon atoms in direct conti-
guity of the O atoms for 1c and 2c, supporting the O–P bonding sit-
uation. The 31P NMR shifts of the series PhxP(L)3ꢀx (x = 2,1,0) for the
naphtholactame derivatives with N–P moiety [2] exhibit a down-
field shift in the sequence d31P (x = 2 < 1 < 0) (Table 1). This behav-
ior is also visible (and more pronounced) for the HLa and HLb
derivatives. For the complete series PhxP(L)3ꢀx of phosphino-func-
tionalized HLa and HLb, we determined the molecular structures
by single-crystal X-ray diffraction (Figs. 1 and 2). As depicted, the
P–N–C–O sequence in 1a and 2a are in the zigzag arrangement,
whereas in 1b and 2b a U-shape is found. For the latter, the
Pꢁ ꢁ ꢁO separations are in the range between 2.931(1) and 3.240
(1) Å. The phenyl groups at the N-methylbenzamidyl fragment in
1a and 2a are stepwise forming a calyx around the P atoms from
1a to 2a. The PꢀN bonds between 1a and 1b or 2a and 2b are equal
or longer for HLa (Table 2), similar to their diphenylphosphino-
functionalized homologs. The N–P–N angles are significantly larger
in 1a and 2a than in 1b and 2b, respectively. The similar structure
differences along the series PhxP(L)3ꢀx (x = 2,1,0; L = N-methylben-
zamidyl, phthalimidyl) explain the almost constant upfield shift of
the 31P NMR signals of PhxP(Lb)3ꢀx relative to the corresponding
31P NMR signals of PhxP(La)3ꢀx
,
by about 30 ppm
(D
(d31P)
= ꢀ27.3 [1] (x = 2), ꢀ32.1 (x = 1), ꢀ26.5 ppm (x = 0)).
In contrast to the series with La and Lb, along the series PhxP
(Lc)3ꢀx (x = 2,1,0; Lc = 2-pyridyloxy), we found a sagging pattern
of the 31P NMR shifts, which has also been observed for the series
PhxP(OPh)3ꢀx (x = 2,1,0) [22,23]. The molecular structures of PhxP
(Lc)3ꢀx (x = 2 [1], 1 (Fig. 1), 0 [17]) determined by single-crystal
X-ray diffraction underpin the formation of O-phosphino deriva-
tives for all Lc fragments, driven by the retention of the aromatic
character of the pyridine moiety.
3.2. Neutral ruthenium(II) bis-chelates [RuCl2(PPh3)(PR(L2))](R = Ph,
L; L = La, Lb, Lc)
The reaction of the 16eꢀ complex [RuCl2(PPh3)3] with 1a,b,c and
2b,c leads (in all five cases) to the formation of the corresponding
all-cis complexes 3a,b,c and 4b,c, respectively, by liberation of two
equivalents of triphenylphosphine (Scheme 3). In addition to the
31P NMR signals of 3a (167.9 ppm, d, J = 38.2 Hz; 54.4 ppm, d,
J = 38.2 Hz) and PPh3 (ꢀ5.4 ppm), the 31P{1H} NMR spectrum of
Table 1
31P NMR shifts of phosphines of the type PhxP(L)3ꢀx in CDCl3 (ppm).
x
La
Lb
1,8-Naphtholactam [2]
Lc
OPh
2
1
0
57.0 [1]
85.4
93.9
29.7 [1]
53.3
67.4
29.7
36.6
57.9
100.6 [1]
148.7 [8]
133.2
110.4 [22]
157.9 [22]
128.6 [23]
Fig. 1. ORTEP drawing of (from left to right) compound 1a, 1b and 1c. Thermal displacement ellipsoids are displayed at the 50% probability level. H atoms and solvent
molecules are omitted for clarity. For 1b only one of the two crystallographically independent (but conformationally identical) molecules is depicted.
Fig. 2. ORTEP drawing of (from left to right) compounds 2a and 2b. Thermal displacement ellipsoids are displayed at the 50% probability level. H atoms and solvent molecules
are omitted for clarity.
Please cite this article in press as: R. Gericke, J. Wagler, Polyhedron (2016), http://dx.doi.org/10.1016/j.poly.2016.08.041

R. Gericke, J. Wagler / Polyhedron xxx (2016) xxx–xxx
7
Table 2
Selected bond lengths (Å) and angles (°) of 1a, 1b, 1c, 2a, 2b.
1a
1b
1c
2a
2b
P–N/O
P–C
1.7287(11)
1.7358(11)
1.7156(12) –
1.7342(12)
1.674(4)
1.675(4)
1.731(4)
1.733(4)
1.740(4)
1.7110(16)
1.7204(14)
1.7251(14)
1.8220(12)
1.8209(14)
1.8245(14)
1.821(5)
C
C
carbonyl–N
1.3857(17)
1.3872(16)
1.3835(17) –
1.3992(17)
1.318(8)
1.314(8)
1.393(6)
1.385(6)
1.373(6)
1.373(2)
1.388(2)
1.387(2)
carbonyl–O
1.2223(16)
1.2237(16)
1.2189(16) –
1.2250(17)
1.379(6)
1.372(6)
1.218(5)
1.222(6)
1.228(6)
1.217(2)
1.219(2)
1.226(2)
N/O–P–N/O
105.49(5)
103.80(6)
103.92(6)
88.3(2)
100.50(19)
100.88(18)
101.51(19)
98.62(7)
99.30(7)
99.62(7)
C–P–N/O
101.74(6)
100.48(5)
120.77(9)
118.86(9)
99.68(6) –
103.96(6)
118.91(9) –
129.72(9)
99.1(2)
100.5(2)
116.3(4)
116.7(4)
P–N/O–Ccarbonyl
117.2(3)
116.9(3)
117.2(3)
121.9(5)
121.3(4)
121.7(5)
118.11(11)
118.63(11)
119.76(13)
123.63(17)
123.98(18)
124.31(15)
N–Ccarbonyl–O
120.67(13)
120.90(12)
124.31(13) –
125.89(12)
116.5(5)
116.6(4)
Table 3
Selected bond lengths (Å) and angles (°) of 3a, 3b and 3c.
PPh3 groups and a P atom from ligand 1a. For the sake of symmetry
and chemical equivalence of the two PPh3 ligands we attribute this
set of signals to the ionic compound 3aIII, which should form upon
loss of a chloride ion. Attempts to isolate 3aIII by adding PPh3 to the
reaction mixture (in order to hamper the conversion into 3a) failed.
In addition to the 31P NMR signals of 3b (127.7 ppm, d,
J = 43.5 Hz; 56.8 ppm, d, J = 43.5 Hz) or 4b (123.6 ppm, d,
J = 48.9 Hz; 52.6 ppm, d, J = 48.9 Hz) and PPh3 (ꢀ5.4 ppm), the 31P
{1H} NMR spectrum of the crude reaction mixture of 1b or 2b
and [RuCl2(PPh3)3] in chloroform shows one extra set of signals
each (3bI: 118.6 ppm, dd, J = 353.4 Hz, J = 38.3 Hz; 48.1 ppm, dd,
J = 38.3 Hz, J = 23.7 Hz; 16.0 ppm, dd, J = 353.4 Hz, J = 23.7 Hz;
4bI: 130.2 ppm, dd, J = 427.9 Hz, J = 46.4 Hz; 48.6 ppm, dd,
J = 46.4 Hz, J = 21.4 Hz; 12.2 ppm, dd, J = 427.9 Hz, J = 21.4 Hz,
respectively). In each set the signals occur also in 1:1:1 intensity
ratio with a coupling pattern of an ABX spin system. In analogy
to 3aI we attribute these signals to compounds 3bI or 4bI. Signals
of an ionic intermediate (sets of signals which would correspond
to those of 3aIII) have not been observed. However, we assume that
for all three ligands 1a,b and 2b, a stepwise replacement of PPh3
takes place by formation of intermediate 3aI,bI and 4bI followed
by 3aIII and corresponding analogs ‘‘3bIII” and ‘‘4bIII”. This stepwise
reaction has not been observed for the formation of 3c or 4c. This
reactivity of the pyridyloxyphosphines is not unexpected: For the
related diphenylphosphino derivative Ph2P-Lc we already reported
rapid formation of the bis-chelate complex [RuCl2(Ph2P-Lc)2] with-
out allowing for the detection of the mono-chelate [RuCl2(PPh3)2(-
Ph2P-Lc)] [1]. In the 31P NMR spectra incorporation of ligands 1a,b,
c and 2b,c in Ru complexes 3a,b,c and 4b,c, respectively, causes a
significant downfield shift of the 31P resonance by about 30–
80 ppm.
3a
3b
3c
Ru1–P1
Ru1–P2
2.1383(12)
2.2805(12)
2.097(3)
2.146(3)
2.3991(11)
2.4635(12)
1.746(4)
1.753(4)
1.794(5)
1.352(6)
1.363(6)
1.263(5)
1.249(6)
81.88(9)
80.13(9)
87.42(12)
99.60(4)
95.60(5)
161.94(5)
93.78(4)
101.88(19)
105.48(19)
101.89(19)
135.56(15)
113.8(3)
113.2(3)
121.8(4)
121.2(4)
2.1797(6)
2.2965(6)
2.1079(15)
2.2052(16)
2.3894(6)
2.4368(6)
1.7388(18)
1.7276(19)
1.800(2)
1.369(3)
1.369(3)
1.251(3)
1.246(3)
82.39(4)
81.71(4)
88.22(6)
97.43(2)
96.91(2)
164.56(2)
88.82(2)
2.1328(4)
2.3103(4)
2.0906(15)
2.1499(14)
2.4108(5)
2.4602(5)
1.6523(13)
1.6602(13)
1.7880(17)
1.346(2)
1.337(2)
1.364(2)
1.362(2)
81.33(4)
79.62(4)
86.71(6)
Ru1–N1/O1
Ru1–N2/O2
Ru1–Cl1
Ru1–Cl2
P1–N1/O1
P1–N2/O2
P1–C
C
carbonyl–N
C
carbonyl–O
P1–Ru1–N1/O1
P1–Ru1–N2/O2
N1/O1–Ru1–N2/O2
P1–Ru1–P2
P1–Ru1–Cl1
P1–Ru1–Cl2
Cl1–Ru1–Cl2
N1/O1–P1–N2/O2
C–P1–N1/O1
C–P1–N2/O2
C–P1–Ru1
100.672(16)
94.011(17)
168.256(16)
91.584(18)
101.78(7)
99.98(7)
101.82(9)
109.99(10)
101.20(10)
134.76(8)
113.44(14)
116.10(15)
124.13(19)
123.5(2)
96.94(7)
140.43(6)
115.80(11)
116.13(11)
118.27(15)
118.08(15)
P–N/O–Ccarbonyl
N–C–O
the crude reaction mixture of 1a and [RuCl2(PPh3)3] in chloroform
shows two extra sets of signals (3aI: 162.4 ppm, dd, J = 347.6 Hz,
J = 35.0 Hz; 47.2 ppm, dd, J = 35.0 Hz, J = 22.2 Hz; 13.4 ppm, dd,
J = 347.6 Hz, J = 22.2 Hz; 3aIII: 167.1 ppm, t, J = 29.0 Hz; 38.5 ppm,
d, J = 29.0 Hz). Three signals in 1:1:1 ratio with a coupling pattern
For 3a,b,c and 4b the identity of the compound was proven by
single-crystal X-ray diffraction structure analyses. In accord with
the NMR spectroscopic data in all cases the all-cis configuration
around the ruthenium atoms was found (Figs. 3 and 4). Selected
bond lengths and angles are listed in Tables 3 and 4. The coordina-
tion of the Ru atom is distorted octahedral. The Ru1ꢀP2 bond
lengths (to PPh3) are about 2.29 Å, whereas the Ru1–P1 bonds (to
the chelating ligand) are much shorter (around 2.14 Å). For 3b
the latter bond is slightly elongated, by about 0.03 Å, in accord
2
of an ABX spin system, with characteristic trans JP,P coupling
2
around 350 Hz and cis JP,P coupling around 30 Hz, is in support
of a structure of a complex 3aI (Scheme 3), as the signal pattern
is similar to its diphenylphosphino analog [1]. With 3aI as an inter-
mediate, the additional set of two signals in 1:2 ratio with a cou-
pling pattern of an AX2 spin system can be attributed to a
compound with facial arrangement of two chemically equivalent
Please cite this article in press as: R. Gericke, J. Wagler, Polyhedron (2016), http://dx.doi.org/10.1016/j.poly.2016.08.041

8
R. Gericke, J. Wagler / Polyhedron xxx (2016) xxx–xxx
Table 4
Selected bond lengths (Å) and angles (°) of 4b, 5a, 7b and 7c.
4b
5a
7b
7c
Ru1–P1
Ru1–P2/P3
2.138(3)
2.292(3)
2.1922(14)
2.3284(14)
2.3168(14)
2.167(3)
2.160(4)
2.4714(14)
2.2166(6)
2.3634(6)
2.3480(6)
2.1958(16)
2.1261(15)
2.4087(5)
2.151(2)
2.3966(19)
2.407(2)
2.207(7)
2.158(6)
2.443(2)
Ru1–N1/O1
Ru1–N2/O2
Ru1–Cl1
2.125(6)
2.175(6)
2.401(2)
2.437(2)
1.715(7)
1.724(7)
1.680(8)
1.364(12)
1.383(12)
1.440(11)
1.234(10)
1.238(11)
1.219(10)
82.25(17)
82.49(18)
87.9(2)
Ru1–Cl2
P1–N1/O1
P1–N2/O2
P1–N3/O3
1.784(5)
1.780(5)
1.483(4)
1.342(8)
1.348(7)
1.726(2)
1.726(2)
1.6861(19)
1.371(3)
1.369(3)
1.431(3)
1.248(3)
1.246(3)
1.213(3)
79.41(4)
81.62(4)
83.73(6)
106.75(2)
159.37(2)
96.18(2)
1.625(6)
1.642(6)
1.563(6)
1.342(12)
1.332(11)
1.302(12)
1.381(13)
1.358(10)
1.423(11)
75.82(19)
80.14 (19)
83.5(2)
C
carbonyl–N
C
carbonyl–O
1.265(7)
1.264(6)
P1–Ru1–N1/O1
P1–Ru1–N2/O2
N1/O1–Ru1–N2/O2
P1–Ru1–P2
P1–Ru1–Cl1
P1–Ru1–Cl2/P3
Cl1–Ru1–Cl2
80.83(10)
81.79(10)
82.76(14)
98.24(5)
161.00(5)
94.01(5)
99.83(9)
94.73(9)
162.85(9)
96.09(8)
98.87(8)
161.03(8)
98.56(8)
P2–Ru–P3
100.68(5)
95.4(2)
101.04(2)
101.28(10)
99.84(9)
104.05(10)
141.07(8)
113.74(15)
114.57(15)
128.18(16)
122.9(2)
100.22(7)
99.5(3)
N1/O1–P1–N2/O2
N3/O3–P1–N1/O1
N3/O3–P1–N2/O2
N3/O3–P1–Ru1
P–N/O–Ccarbonyl
103.0(4)
103.5(4)
99.7(4)
139.4(3)
112.7(6)
114.0(6)
125.5(6)
125.3(8)
124.5(8)
123.2(8)
106.4(2)
104.8(2)
139.18(17)
115.6(4)
116.3(3)
102.4(3)
101.7(3)
134.5(2)
112.8(5)
118.2(5)
131.5(6)
116.9(7)
118.1(7)
117.4(8)
N–C–O
121.2(5)
120.5(5)
123.8(2)
125.1(2)
with a slightly shorter (by 0.02 Å) trans located Ru1–Cl2 bond. The
trans to PPh3 located Ru1–N2/O2 bonds are longer by approxi-
mately 0.05 Å in comparison to the trans to Cl located Ru–N1/O1
bonds. For 3b, this bond length difference amounts to 0.1 Å. Also,
3b reveals the smallest Cl1–Ru1–Cl2 angle, which may originate
from the set of intramolecular CHꢁ ꢁ ꢁCl contacts of the ortho-H
atoms from the phenyl groups, which, in this fashion, is found in
3b only. Compound 3c exhibits the largest P1–Ru1–Cl1 angle
caused by intramolecular CHꢁ ꢁ ꢁCl contacts of the H6 atoms of the
2-pyridyloxy fragments.
ing 4aI, which isomerizes to 4aII. After dissociation of one Clꢀ ion
(similar to 3aIII), 4aIII is formed, where the tripodal ligand is acting
as a bis-chelator. The dangling N-methylbenzamidyl fragment
undergoes an NꢀP bond cleavage and rearranges to the O-phos-
phino derivative (most likely for steric reasons). Thereafter, the
Clꢀ ion acts as nucleophile and attacks the carbonyl carbon atom,
thus splitting off N-methylbenzimidoylchloride (detected by 13C
{1H} NMR spectroscopy [24]) and simultaneously forming 5a. Upon
adding TlPF6 to the reaction mixture, 6 has been formed instead of
N-methylbenzimidoylchloride (Scheme 4). In an analogous man-
ner, the reaction mixtures of 2b or 2c and [RuCl2(PPh3)3] were trea-
ted with TlPF6. These reactions did not yield products similar to 5a.
Instead, the reactions terminate at 7b and 7c (analogous isomers to
4aIII). In addition to the 31P NMR signals of 7b (128.0 ppm, t,
J = 39.0 Hz; 40.4 ppm, d, J = 39.0 Hz), PPh3 (ꢀ5.4 ppm) and the
characteristic 1JP,F coupling of PFꢀ6 (ꢀ144.3 ppm, sept.,
J = ꢀ713.6 Hz), the 31P{1H} NMR spectrum of the crude reaction
mixture for 2b and [RuCl2(PPh3)3] with TlPF6 in chloroform shows
an extra set of signals (7bI: 129.9 ppm, dd, J = 428.5 Hz, J = 48.2 Hz;
48.6 ppm, dd, J = 48.2 Hz, J = 22.4 Hz; 12.1 ppm, dd, J = 428.5 Hz,
J = 22.4 Hz). The three signals appear in 1:1:1 intensity ratio, as
3.3. Neutral or cationic ruthenium(II) bis-chelates [RuCl(PPh3)2(PR
(L2))](R = O, L; L = La, Lb, Lc)
Reacting 2a and [RuCl2(PPh3)3] in chloroform in analogous
manner to 2b,c did not afford a similar product to 4b,c. Instead
compound 5a was isolated (Scheme 3). In addition to the 31P
NMR signals of 5a (142.8 ppm, t, J = 44.3 Hz; 47.2 ppm, d,
J = 44.3 Hz) and PPh3 (ꢀ5.4 ppm), the 31P{1H} NMR spectrum of
the crude reaction mixture of 2a and [RuCl2(PPh3)3] in chloroform
shows two extra sets of signals (4aI: 139.5 ppm, dd, J = 416.9 Hz,
J = 54.4 Hz; 55.3 ppm, dd, J = 54.4 Hz, J = 13.8 Hz; 10.2 ppm, dd,
J = 416.9 Hz, J = 13.8 Hz; 4aII: 154.2 ppm, dd, J = 48.0 Hz,
J = 41.0 Hz; 49.1 ppm, dd, J = 48.0 Hz, J = 32.9 Hz; 41.0 ppm, dd,
J = 41.0 Hz, J = 32.9 Hz). The signals of the first ABX spin system
occur in 1:1:1 intensity ratio (4aI) similar to 3aI, 3bI and 4bI. The
signals of 4aI disappear during the reaction, whereas the signals
of a second ABX spin system (1:1:1 ratio) with coupling constants
expected. Apparently, compound 4b is formed first, where the
´
longer RuꢀCl bond trans to the chelating ligands
P atom
(Ru1ꢀCl2 ꢃ 0.04 Å longer than the Ru1ꢀCl1 bond trans to an O
atom) is cleaved by TlPF6 to form 7bI, which isomerizes to 7b. For-
mation of an intermediate ‘‘7cI”, which would correspond to 7bI,
could not be detected for the reaction of 2c and [RuCl2(PPh3)3] with
TlPF6. As compounds 7b and 7c already have a conformation
related to compound 5a (with facial arrangement of the P atoms),
a transformation of 7b into the 5a-related phthalimidyl-bridged
compound was aimed at by adding one equivalent of a chloride
ion source (tetra-butylammonium chloride) and an additional
2
in the typical range of cis JP,P coupling, were detected as traces in
the reaction mixture and were attributed to the isomer 4aII. For the
formation of 5a we suggest the following route (Scheme 3): At first,
one PPh3 group is replaced by 2a acting as bidentate ligand form-
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R. Gericke, J. Wagler / Polyhedron xxx (2016) xxx–xxx
9
Scheme 3. Synthesis of compounds 3a,b,c, 4b,c and 5a.
Fig. 3. ORTEP drawing of (from left to right) compound 3a, 3b and 3c. Thermal displacement ellipsoids are displayed at the 50% probability level. H atoms and solvent
molecules are omitted for clarity.
equivalent of PPh3. Instead of nucleophilic attack at the dangling
ligand Lb, however, slow chloride addition to ruthenium with for-
mation of compound 4b was observed.
We succeeded in crystallizing (and determining the crystal
structures of) all three bis(triphenylphosphine) ruthenium(II) bis-
chelates 5a and 7b,c (Figs. 4 and 5). All structures show a distorted
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10
R. Gericke, J. Wagler / Polyhedron xxx (2016) xxx–xxx
Fig. 4. ORTEP drawing of (from left to right) compound 4b, 5a and 6. Thermal displacement ellipsoids are displayed at the 50% probability level. H atoms, the PFꢀ6 counterion of
6 and solvent molecules are omitted for clarity.
ever, can be assumed to cause the shorter RuꢀCl bonds in these
complexes (2.41 and 2.44 Å, respectively), while the negative
charge of the tridentate ligand in 5a may contribute to elongation
of the trans-disposed RuꢀCl bond (2.47 Å). In contrast, the bond
lengths RuꢀP1 (7c 2.15 Å, 5a 2.19 Å, 7b 2.22 Å) do not adhere to
systematic differences in ligand charge or steric demand (because
of the intermediate position of 5a) but seem to vary with the PNx-
O3ꢀx substitution pattern of P1 (7c x = 3, 5a x = 1, 7b x = 0) as the
RuꢀP1 bond is shorter for O-rich (presumably pronounced
p-
acceptor) phosphorus atoms. The same trend (i.e., dependence on
the PNxO3ꢀx substitution pattern of P1) is reflected by the 31P
NMR shifts of P1 (7c 162.6 ppm, 5a 142.8 ppm, 7b 128.0 ppm)
2
and JP,P coupling constants with the cis-disposed PPh3 ligands
(7c 48 Hz, 5a 44 Hz, 7b 39 Hz). The 31P NMR shifts of the PPh3
ligands, however, reflect the trend of the RuꢀPPh3 bonds (7c
36.4 ppm, 7b 40.4 ppm, 5a 47.2 ppm), i.e., shift to lower field with
decreasing RuꢀP bond length.
A closer look at the aromatic range of the 1H NMR spectra of the
pyridyloxyphosphine derivatives 2c, 3c, 4c and 7c hints at the 1H
resonances of the H6 atoms as a probe for the pyridyloxy binding
mode in these complexes (Fig. 6). In the range 9.4–9.9 ppm a char-
acteristically shaped multiplet is observed for 3c and 4c, which is
assigned to the Lc group trans-disposed to a PPh3 group. The extra
Scheme 4. Synthesis of compounds 5a, 6, 7b and 7c.
4
octahedral coordination around the Ru atom with facial arrange-
ment of the phosphorus donors. Although these complexes are
structurally related, complex 5a does not carry a net charge
(because of the anionic tridentate O,P,O ligand), whereas 7b and
7c are cationic. This difference appears to have some effect on fea-
tures of the molecular structures. The Ru1ꢀP2 and Ru1ꢀP3 bonds
in 7b,c are longer than the corresponding bonds in 5a, most likely
caused by the higher steric demand of the dangling phthalimidyl or
2-pyridyloxy fragment. The cationic net charge of 7b and 7c, how-
coupling is caused by the JP,H coupling. In the range 8.7–9.0 this
extra coupling is only visible for 7c, whereas the chemical shift is
closer to the corresponding Lc groups trans located to a chlorine
atom as in 3c and 4c. Apparently, the coupling pattern (or signal
shape arising therefrom) is more characteristic than the chemical
shift itself. From 8.1 to 8.6 ppm we observed the typical chemical
shift of compound 2c, which definitely does not coordinate to a
Ru atom. For 3c no signal is detected, as expected, whereas for
4c and 7c a signal of the dangling pyridyloxy H6 is found.
Fig. 5. ORTEP drawing of (from left to right) compound 7b and 7c. Thermal displacement ellipsoids are displayed at the 50% probability level. H atoms, PFꢀ6 counterions and
solvent molecules are omitted for clarity.
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R. Gericke, J. Wagler / Polyhedron xxx (2016) xxx–xxx
11
Appendix A. Supplementary data
CCDC 1490791, 1490789, 1490786, 1490788, 1490787,
1490797, 1490794, 1490793, 1490785, 1490795, 1490792,
1490790, 1490796 contains the supplementary crystallographic
data for 1aꢁ0.75THF, 1b, 1c, 2a, 2bꢁTHF, 3aꢁ3CH2Cl2, 3bꢁ1.95CHCl3,
3cꢁ1.5CHCl3, 4bꢁ2CH2Cl2, 5aꢁ3THF, 6, 7bꢁCHCl3ꢁ2Et2O, 7cꢁCHCl3.
These data can be obtained free of charge via http://www.
ccdc.cam.ac.uk/conts/retrieving.html, or from the Cambridge Crys-
tallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK;
fax: (+44) 1223-336-033; or e-mail: deposit@ccdc.cam.ac.uk. Sup-
plementary data associated with this article can be found, in the
online version, at http://dx.doi.org/10.1016/j.poly.2016.08.041.
Fig. 6. Selected aromatic range of 1H NMR spectra of 2c, 3c, 4c and 7c.
4. Conclusions
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Four new P,O-chelating ligands (1a, 1b, 2a and 2b) and two P,N-
chelating ligands (1c and 2c) have been synthesized and their coor-
dination behavior towards ruthenium(II) has been examined. In all
cases, regardless of potentially bi- (ligands 1) or tripodal ligand
characteristics (ligands 2), the final products featured the
ambidentate ligand in bipodal O,P,O (ligands 1a, 1b, 2a, 2b) or N,
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Acknowledgements
R.G. is grateful to the Studentenwerk Freiberg and the Free State
of Saxony for a Ph.D. scholarship (Landesgraduiertenstipendium).
Please cite this article in press as: R. Gericke, J. Wagler, Polyhedron (2016), http://dx.doi.org/10.1016/j.poly.2016.08.041