Synthesis, X-ray structural and DFT studies of n-membered ring P, C-chelated complexes of Pd(II) and pt(II) derived from unsymmetrical phosphorus ylides and application of pd(II) complexes as catalyst in suzuki reaction

Article abstract of DOI:10.1080/00958972.2017.1397640

The phosphonium salts [Ph₂P(CH₂)_nPPh₂CH₂C(O)C₆H₄-m-OMe]Br (n = 1 (S₁) and n = 2 (S₂)) were synthesized in the reaction of bis(diphenylphosphino) methane (dppm) and bis(diphenylphosphino)ethane (dppe) with 2-bromo-3?-methoxy acetophenone, respectively. Further treatment with NEt₃ gave the phosphorus ylides Ph₂P(CH₂)_nPPh₂C(H)C(O)C₆H₄-m-OMe (n = 1 (Y₁) and n = 2 (Y₂)). These ligands were treated with [MCl2(cod)] (M = Pd or Pt; cod = 1,5-cyclooctadiene) to give the P, C-chelated complexes, [MCl₂(Ph₂P(CH₂)_nPPh₂C(H)C(O)C₆H₄-m-OMe)] (n = 1, M = Pd (3), Pt (4), and n = 2, M = Pd (5), Pt (6)). These compounds were characterized by elemental analysis, spectroscopic methods, UV–visible, and fluorescence emission spectra. Further, the structures of complexes 3 and 6 were characterized crystallographically. The palladium complexes 3 and 5 proved to be excellent catalysts for the Suzuki reactions of various aryl chlorides. Also, a theoretical study on the structure of complexes 3–6 has been investigated at the BP86/def2-SVP level of theory. The strength and nature of donor?acceptor bonds between the phosphorus ylides (L) and MCl₂ fragment in the [LMCl2] (M = Pd, Pt, L = Y₁, Y₂) were studied by NBO and energy decomposition analysis (EDA), as well as their natural orbitals for chemical valence variation (EDA-NOCV).

Full text of DOI:10.1080/00958972.2017.1397640

Journal of Coordination Chemistry
ISSN: 0095-8972 (Print) 1029-0389 (Online) Journal homepage: http://www.tandfonline.com/loi/gcoo20
Synthesis, X-ray structural and DFT studies of n-
membered ring P, C-chelated complexes of Pd(II)
and Pt(II) derived from unsymmetrical phosphorus
ylides and application of Pd(II) complexes as
catalyst in Suzuki reaction
Seyyed Javad Sabounchei, Mohsen Sayadi, Mehdi Bayat, Asiyeh Sedghi &
Robert W. Gable
To cite this article: Seyyed Javad Sabounchei, Mohsen Sayadi, Mehdi Bayat, Asiyeh Sedghi
& Robert W. Gable (2017): Synthesis, X-ray structural and DFT studies of n-membered ring P,
C-chelated complexes of Pd(II) and Pt(II) derived from unsymmetrical phosphorus ylides and
application of Pd(II) complexes as catalyst in Suzuki reaction, Journal of Coordination Chemistry,
DOI: 10.1080/00958972.2017.1397640
To link to this article: http://dx.doi.org/10.1080/00958972.2017.1397640
View supplementary material
Accepted author version posted online: 26
Oct 2017.
Submit your article to this journal
View related articles
View Crossmark data
Full Terms & Conditions of access and use can be found at
http://www.tandfonline.com/action/journalInformation?journalCode=gcoo20
Download by: [University of Florida]
Date: 27 October 2017, At: 06:58

Publisher: Taylor & Francis
Journal: Journal of Coordination Chemistry
DOI: http://doi.org/10.1080/00958972.2017.1397640
Synthesis, X-ray structural and DFT studies of n-membered ring
P, C-chelated complexes of Pd(II) and Pt(II) derived fromunsymmetrical
phosphorus ylides and application of Pd(II) complexes as
catalyst in Suzuki reaction
SEYYED JAVAD SABOUNCHEI*†, MOHSEN SAYADI†, MEHDI BAYAT†, ASIYEH SEDGHI† and
ROBERT W. GABLE‡
†Faculty of Chemistry, Bu-Ali Sina University, Hamedan,65174, Iran
‡School of Chemistry, University of Melbourne, Victoria, 3010, Australia
The phosphonium salts [Ph2P(CH2)nPPh2CH2C(O)C6H4-m-OMe]Br (n=1 (S1) and n=2 (S2)) were
synthesized in the reaction of bis(diphenylphosphino)methane (dppm) and
bis(diphenylphosphino)ethane (dppe) with 2-bromo-3ʹ-methoxy acetophenone, respectively.
Further treatment with NEt3 gave the phosphorus ylides Ph2P(CH2)nPPh2C(H)C(O)C6H4-m-OMe
(n=1 (Y1) and n=2 (Y2)).These ligands (Y1 and Y2) were treated with [MCl2(cod)] (M= Pd or Pt;
cod = 1,5-cyclooctadiene)to give the P, C-chelated complexes,
[MCl2(Ph2P(CH2)nPPh2C(H)C(O)C6H4-m-OMe)] (n=1, M= Pd (3), Pt (4) and n=2, M= Pd (5), Pt
(6)). These compounds were characterized by elemental analysis, spectroscopic methods,
UV-visible and fluorescence emissionspectra. Further,thestructures of complexes 3 and 6 were
characterized crystallographically.These structures consist of five- and six-membered rings
formed by coordination of the ligand through the phosphine group and the ylidic carbon atom to
the metal center. The palladium complexes 3 and 5 proved to be excellent catalysts for the
Suzukireactions of various aryl chlorides and arylboronic acids in mixed DMF/H2O media. Also,
a theoretical study on the structure of complexes 3-6has been investigated at the BP86/def2-SVP
level of theory. The strength and nature of donor−acceptor bonds between the phosphorus ylides
(L) and MCl2 fragment in the [LMCl2] (M= Pd, Pt, L= Y1, Y2) were studied by NBO and energy-
decomposition analysis (EDA), as well as their natural orbitals for chemical valence variation
*Corresponding author. Email: jsabounchei@yahoo.co.uk
1

(EDA-NOCV). The results confirmed that the contributions of the electrostatic interaction in the
L→M bonds in the complexes are about 56-58%.
Keywords: Palladium and platinum; Ylide; X-ray structure; Suzuki reaction; DFT, EDA
Analysis; EDA-NOCV, Nature of bond
1. Introduction
The coordination and organometallic chemistry ofunsymmetricalα-keto stabilized phosphorus
ylides have been investigated extensively and their ambidenticity explained in terms of a delicate
balance between electronic and steric factors [1-3].Much of the interest in the coordination
properties of α-keto stabilized phosphorus ylides stems from their coordination versatility due to
the presence of different functional groups in their molecular structure [4].Thus, these ligands
can engage in different kinds of bonding with different metal ions: P-bonded (through the
phosphine group), C-bonded (through the Cα atom), O-bonded (through the carbonyl O), or even
situations in which the same ylide shows a combination of bonding modes.Different types of
bonding are depicted in Chart 1 for Ph2P(CH2)nPPh2C(H)C(O)C6H4R.
In Chart 1, when a metal ion such as Rh(I), Hg(II) or Ag(I) interacts only with the free P
atom of the diphosphine group (a), the coordination structure is regarded as monodentate [5, 6].If
the coordination of ylide occurs through the Cα atom of the ylidic group (b), it is categorized in
the same above mentioned coordination mode [7],although the ylides can also coordinate to the
metal ions through the O atoms of the carbonyl group (c). A few examples of O-coordinated
ylidesare known; some of these complexes include a hard and very oxophilic metal center, such
as Sn(IV) [8], Ti(IV), Zr(IV) or Hf(IV) [9].
The P, C-coordination mode (d) of stabilizedphosphorus ylides had been previously
observed for Pd(II), Pt(II), Rh(I), Hg(II) and Cu(I) species [10-18].Although the P, O-
coordination mode (e)is also possible, to the best of our knowledge, it has only been observed in
the Pd(II) complexes of a mixed phosphine–β-ketophosphorus ylide [19]. Finally, the bridging
coordination mode (f and g) is observed when a metal ion binds to one phosphorus ylide through
the P atom and another metal ion binds to the Cα or O atom [20]. The investigation of reactivity
and coordination chemistry of carbonyl stabilized ylides is an important research field of our
group [5-7, 21]. Recently, our group reported the synthesis and application of Pd(II) and Cu(I)
2

complexescontaining phosphine-ylide ligands [13, 17]. It was shown that the reaction of
phosphine-ylide ligands with Pd(II) and Cu(I) give the P, C-chelated complexes. In this context,
we have now focused our attention in the study of the coordination modes adopted by the
resonance stabilized ylides when ligated to Pd(II)and Pt(II).
f
e
M
M
M
M
M
c
a
O
b
O
M
O
Ph2
P
Ph2
P
Ph2
R
R
Ph2P
Ph2P
R
Ph2P
P
C
H
C
H
C
H
(CH2)n
(CH2)n
(CH2)n
M
d
M
M
g
monodentate
bidentate
bridging
f:
g:
a:
b:
c:
P-bonding
C-bonding
O-bonding
d:
P, C-bonding
P, O-bonding
P, C-bonding
e:
P, O-bonding
Chart 1. Possible bonding modes of phosphorus ylides to the metal M.
Bidentate diphosphines are valuable ligands for metal-catalyzed reactions. Metal-
catalyzed cross-coupling reactions have gained popularity over the past 30 years, in particular as
convenient techniques for the formation of C-C bonds [22-24].Palladium-catalyzed reactions,
such as C-C bond formation, have attractedconsiderable interest [25, 26]. Specifically, the
Suzuki reaction which emerged as the most important and reliable method for construction of
functionalized biaryl compounds,has been catalyzed recently with the P, C-chelated Pd(II)
complexes of such phosphorus ylides [27-31].Current technologies demand new catalysts, which
are inexpensive, readily accessible, moisture- and air-stable, and most importantly, highly
effective under low catalyst loading [32]. Recently, our group reported the synthesis and
application of palladium complexes of phosphorus ylides as efficient catalysts for some classical
Suzuki reactions[24, 33-35]. These compounds, due to their readily preparation, high activity and
relative stability, can be used as efficient catalyst precursors in Suzuki reactionsof various aryl
bromides under relatively mild experimental conditions.
3

The results of these studies including the full characterization of the obtained complexes
(performed by elemental analysis,X-ray structural,IR, multinuclear NMR techniques, theoretical
studyand also application of the new palladium(II) complexes of phosphorus ylide Suzuki
reaction) is presented and discussed in this paper.
2. Experimental
2.1. Materials and methods
Manipulations were performed in typical Schlenk systems under an atmosphere of dry nitrogen,
and the progress of reactions was monitored by IR and NMR spectroscopies. The starting
complexes [PdCl2(cod)] and [PtCl2(cod)] were prepared according to previously published
procedures [36]. Reactants and reagentswere obtained from Merck chemical company and used
without purification.The solvents were dried and distilled using standard methods [37].
Elemental analyses for C, H and N were performed using a PerkinElmer 2400 series analyzer.
Melting points were measured on a SMPI apparatus and are reported without correction. The1H,
13C and 31P NMR spectra were run on a BrukerAvance 500 MHz, 250 MHz and Jeol 90 MHz
spectrometers in CDCl3 or DMSO-d6 as solvents at 25 °C. The chemical shifts (d) are referred to
Me4Si (using the residual proton peaks of deuterated solvents) and to external 85% H3PO4.IR
spectra were taken by a FT-IR Shimadzu 435-U-04 of the Nicolet Instrument Corporation
(4000–400 cm-1) spectrophotometer. UV-vis spectra were recorded on a Perkin voyager DE-PRO
spectrometer inthe region of 300–800 nm and the fluorescence emissionspectra wereperformed
on a Varian Cary spectrofluorometer.
2.2. X-ray crystallography
Suitable crystalsof3and6 were selected and mounted on a Rigaku Oxford Diffraction SuperNova,
Dual, Cu at zero, Atlas diffractometer. Data collection and reduction was carried out using
CrysalisPro [38], with the data for both structures being corrected for absorption using Gaussian
integration.The crystal was kept at 130.00(10) K during data collection. Using Olex2 [39], the
structure was solved with the ShelXS [40] structure solution program using direct methods and
refined with the ShelXL [41] refinement package using Least Squares minimization. All non-
hydrogen atoms were refined with anisotropic displacement parameters. Hydrogens were
4

constrained to geometrical estimates, with an isotropic displacement parameter of 1.5 times (Me)
or 1.2 times (other) the parent carbon atom.
2.3.Computational details
The geometries of the bidentate phosphorus ylide (Y1 and Y2) complexes of metal halides
palladium and platinum with general formula [LMCl2] (M=Pd, Pt, L= Y1, Y2) have been
optimized at the BP86 [42, 43]/def2-SVP [44] level of theory. It has been shown that in former
studies the BP86 is a suitable level for calculation of bonding situation between the M←L in
these complexes [45-52]. All calculations were performed using the Gaussian 09 set of programs
[53]. NBO analyses [54] were also carried out with the internal model GAUSSIAN 09. For
bonding analyses, the terms of EDA analysis were carried out at
BP86/TZ2P(ZORA)//BP86/def2-SVP with C1 symmetry. The basis sets for all elements have
triple-f quality augmented by one set of polarization functions (ADF basis set TZ2P (ZORA))
with the program package ADF2009.01.
2.4.Preparation of compounds
2.4.1.Synthesis of phosphonium salts S1and S2. General procedure:To a solution of
bis(diphenylphosphino)methane (dppm)orbis(diphenylphosphino)ethane (dppe)(0.52 mmol) in 5
ml of chloroform, a solution (5 ml, CHCl3) of 2-bromo-3ʹ-methoxy acetophenone (0.118 g, 0.52
mmol) was added dropwise. The resulting reaction mixture was stirred for 15 h at room
temperature. The solution was concentrated under reduced pressure to 2 ml, and diethyl ether
(20 ml) was added. The yellow solid formed was filtered off, washed with diethyl ether and dried
under reduced pressure.
2.4.1.1. Data for (3-methoxybenzoylmethyldiphenyldiphenylphosphinomethylphosphonium)-
bromide(S1).Yield: 0.28 g (88%). Anal. Calc. for C34H31O2P2Br (%): C, 66.57; H, 5.09. Found:
C, 66.49; H, 5.04. M.p. 187–189°C. Selected IR absorption in KBr (cm-1): 1671 (ν C=O).
1H NMR (89.60 MHz, CDCl3) δH (ppm): 3.90 (s, 3H, OCH3); 4.28 (d, 2H, PCH2P, 2JP-H
14.69 Hz); 5.92 (d, 2H, PCH2CO, 2JP-H= 11.82 Hz); 7.26–8.02 (m, 24H, Ph).31P NMR
=
(36.26 MHz, CDCl3) δP (ppm): -29.00 (d, PPh2, 2JP-P = 62.16 Hz); 21.07 (d, PCH2, 2JP-P=
5

62.45 Hz). 13C NMR (62.90 MHz, CDCl3)δC (ppm): 192.20 (s, CO); 112.51-159.84 (m, Ph);
56.07 (s, OCH3); 36.86 (d, PCH2CO, 1JP-C= 60.38 Hz); 22.12 (dd, PCH2, 1JP-C = 53.46 Hz).
2.4.1.2. Data for (3-methoxybenzoylmethyldiphenyl-2-diphenylphosphinoethylphosphonium)-
bromide (S2).Yield: 0.30 g (98%). Anal. Calcd for C35H33O2BrP2(%): C, 66.99; H, 5.30. Found:
C, 67.05; H, 5.34. M.p 170–172°C. Selected IR absorption in KBr (cm-1): 1660(ν C=O).1H NMR
(89.60 MHz, CDCl3) δH (ppm):2.32 (m, 2H, PCH2), 3.29 (m, 2H, PCH2), 3.95 (s, 3H, OCH3),
6.02 (dd, 2JP–H = 12.00, 2H, PCH2CO), 7.27–8.12 (m, 24H, Ph). 31P NMR (36.23 MHz, CDCl3)
δP (ppm): -12.07 (br, PPh2), 24.02 (d, PCH2,3JP-P = 48.41 Hz).13C NMR (62.90 MHz, CDCl3)δC
(ppm): 192.01 (s, CO), 112.74-159.83 (m, Ph), 55.97 (s, OCH3), 35.90 (d,PCH2CO, 1JP–C
59.12), 22.46 (d, PCH2, 1JP–C = 66.67), 16.79 (d, PCH2, 1JP–C = 52.83).
=
2.4.2. Synthesis of phosphorus ylides Y1 and Y2. General procedure: The phosphonium salts
S1 and S2 (0.45 mmol) were treated with triethyl amine (0.5 ml, 3.57 mmol) in toluene (15 ml).
The triethyl amine hydrobromide produced was filtered off and the toluene layer concentrated to
5 ml which upon further addition of petroleum ether (25 ml) results in the precipitation of Y1 and
Y2 as free-flowing white solids. The productswere collected and dried under vacuum.
2.4.2.1.Data for 3-methoxybenzoylmethylenediphenyldiphenylphosphinomethylphosphorane
(Y1). Yield: 0.21 g (78%). Anal. Calc. for C34H30O2P2 (%): C, 76.68; H, 5.68. Found: C, 76.61;
H, 5.59. M.p. 168–170°C. Selected IR absorption in KBr (cm-1): 1586(νC=O).1H NMR
(89.60 MHz, CDCl3)δH(ppm): 3.67 (d, 2H, PCH2P, 2JP-H = 13.44 Hz); 3.83 (s, 3H, OCH3); 4.02
(m, 1H, CH); 6.86–7.76 (m, 24H, Ph). 31P NMR (36.26 MHz, CDCl3)δP(ppm): -29.55 (d,PPh2,
2JP-P = 63.50 Hz); 11.34 (d, PCH, 2JP-P= 62.99 Hz). 13C NMR (62.90 MHz, CDCl3)δC (ppm):
184.68 (s, CO);111.06-159.35 (m, Ph); 55.32 (s, OCH3); 50.39 (d, PCH, 1JP-C= 113.22 Hz);24.73
(dd, CH2, 1JP-C = 90.57 Hz).
2.4.2.2.Data for 3-methoxybenzoylmethylenediphenyl-2-diphenylphosphinoethylphosphorane
(Y2). Yield: 0.194 g (73%).Anal. Calc. for C35H32O2P2(%): C, 76.91; H, 5.90. Found: C, 77.14;
H, 6.02. M.p 136-140 °C. Selected IR absorption in KBr (cm-1): 1524(ν C=O).1H NMR
(89.60 MHz, CDCl3) δH(ppm): 2.28 (m, 2H, PCH2), 2.77 (m, 2H, PCH2), 3.85 (s, 3H, OCH3),
6

4.15 (br, 1H, PCH), 6.91–7.49 (m, 24H, Ph). 31P NMR (36.27 MHz, CDCl3) δP(ppm): -13.63 (d,
PPh2,3JP-P = 47.87 Hz), 17.59 (d, PCH,3JP-P = 47.87 Hz). 13C NMR (75.47 MHz, CDCl3) δC
(ppm): 185.02 (s, CO), 111.19-159.52 (m, Ph), 55.36 (s, OCH3), 47.03 (d, PCH,1JP-C= 113.51),
20.80 (m, CH2).
2.4.3. Synthesis of Pd(II) and Pt(II)complexes. General procedure:To a [MCl2(cod)] (M= Pd
or Pt) (0.5 mmol) dichloromethane solution (5 ml), a solution ofY1or Y2(0.5 mmol) (5 ml,
CH2Cl2) was added dropwise. The resulting solution was stirred for 2 h at room temperature and
then concentrated to ca.2 ml under reduced pressure and treated with n-hexane (15 ml) to afford
Pd(II) and Pt(II) complexes.
2.4.3.1. Data for dichloro(3-methoxybenzoylmethylenediphenyldiphenylphosphino-
methylphosphorane)palladium(II)(3).Yield: 0.28 g (80%). Anal. Calc. for C34H30Cl2O2P2Pd(%):
C, 57.53; H, 4.26. Found: C, 57.64; H, 4.17. M.p. 192-194 °C (dec). Selected IR absorption in
KBr (cm-1) ν(CO): 1619. 1H NMR (500.13 MHz, DMSO-d6) δH (ppm): 3.82 (s, 3H, OCH3); 4.78
(d,CH2, 2H, 2JP-H = 185.04 Hz); 5.94 (s, 1H, PCH); 7.15–8.28 (m, 24H, Ph). 31P NMR (202.45
MHz, DMSO-d6) δP (ppm): 28.34 (d, PPh2, 2JP-P= 55.33 Hz); 38.77 (d, PCH, 2JP-P= 58.63 Hz).
13C NMR (62.90 MHz, DMSO-d6) δC (ppm): 196.81 (s, CO), 113.93-139.17(m, Ph), 55.83 (s,
OCH3),27.94 (d, PCH), 21.93 (d, CH2, 1JP-C= 58.49 Hz).
2.4.3.2. Data for dichloro(3-methoxybenzoylmethylenediphenyldiphenylphosphino-
methylphosphorane)platinum(II)(4).Yield: 0.30 g (78%). Anal. Calc. for C34H30Cl2O2P2Pt(%):
C, 51.14; H, 3.79. Found: C, 51.29; H, 3.92. M.p. 210-212 °C (dec). Selected IR absorption in
KBr (cm-1) ν(CO): 1627. 1H NMR (250.13 MHz, DMSO-d6) δH (ppm): 3.79 (s, 3H, OCH3);4.64
(br, PCH2P, 2H); 5.68 (t, 1H, PCH); 7.17–8.25 (m, 24H, Ph). 31P NMR (101.25 MHz, DMSO-d6)
δP (ppm): 4.43 (d, PPh2, 1JPt-P= 3970.98 Hz, 2JP-P= 39.48 Hz);42.22 (d, PCH, 2JP-P = 39.48 Hz).
13C NMR (62.90 MHz, DMSO-d6) δC (ppm): 196.71 (s, CO); 121.92-135.08(m, Ph); 55.94 (s,
OCH3);28.00 (d, PCH, 1JP-C = 66.04 Hz).
2.4.3.3.Data for dichloro(3-methoxybenzoylmethylenediphenyl-2-
diphenylphosphinoethylphosphorane)palladium(II) (5).Yield: 0.29 g (82%). Anal. Calc. for
7

C35H32Cl2O2P2Pd(%): C, 58.07; H, 4.46. Found: C, 57.98; H, 4.41. M.p. 191-193 °C (dec).
Selected IR absorption in KBr (cm-1) ν(CO): 1626. 1H NMR (89.60 MHz, DMSO-d6) δH (ppm):
3.55-4.00 (br, CH2, 4H merged with residual H2O); 3.78 (s, 3H, OCH3); 6.18 (b, 1H, PCH),
7.11–8.44 (m, 24H, Ph). 31P NMR (101.25 MHz, DMSO-d6) δP (ppm): 22.77 (d, PPh2, 2JP-P
29.36 Hz), 30.90 (d, PCH, 2JP-P = 23.28 Hz). 13C NMR (62.90 MHz, DMSO-d6) δC (ppm):
195.97 (s, CO), 114.09-159.30(m, Ph), 55.78 (s, OCH3), 28.82 (d, PCH), 19.45(m, CH2).
=
2.4.3.4. Data fordichloro(3-methoxybenzoylmethylenediphenyl-2-
diphenylphosphinoethylphosphorane)platinum(II) (6).Yield: 0.303 g (80%). Anal. Calc. for
C35H32Cl2O2P2Pt(%): C, 51.74; H, 3.97. Found: C, 51.87; H, 4.10. M.p. 237-239 °C (dec).
Selected IR absorption in KBr (cm-1) ν(CO): 1634. 1H NMR (89.60 MHz, DMSO-d6) δH (ppm):
2.2 (br,CH2, 2Hmerged with DMSO); 3.78 (b, 3H, OCH3); 4.24 (br,CH2, 4Hmerged with
residual H2O); 5.49 (b, 1H, PCH), 7.01–8.44 (m, 24H, Ph). 31P NMR (36.26 MHz, DMSO-d6) δP
(ppm): 6.60 (d, PPh2, 1JPt-P= 3979.03 Hz, 2JP-P= 17.77 Hz), 20.14 (d, PCH, 2JPt-P= 132.73 Hz,
2JP-P= 17.77 Hz). 13C NMR (62.90 MHz, DMSO-d6) δC (ppm): 196.11 (s, CO), 114.07-
159.28(m, Ph), 55.76 (s, OCH3), 35.30 (d, PCH), 19.90 (m, CH2).
2.5. General procedure for the Suzuki reaction
A mixture ofaryl halide (0.75 mmol), K2CO3 (1.5 mmol), phenylboronic acid (1 mmol),
0.005 mmol of Pd(II) complex 3ascatalystand 2 mL DMF/H2O (1:1) as solvent was heated at 130
°C using an oil bath and the progress of the reactionwas monitored byTLC. The reaction mixture
was then cooled to room temperature. After completion of the reaction, the mixture was diluted
with n-hexane (15 mL) and water (15 mL). The combined organic layerwas washed with brine
(15 mL) and dried over CaCl2. Then solvent was evaporated and pure biphenyl derivatives were
obtained in good to excellent yields.
2.5.1. Data for4-nitrobiphenyl (7a). Yield: 0.183 g (92%).M.p. 112-113 °C. 1H NMR
(89.6 MHz, CDCl3) δH (ppm): 7.26-8.34 (m, 9H, phenyl). 13C NMR (62.89 MHz, CDCl3) δC
(ppm): 147.68, 146.97, 128.92, 127.84, 124.10.
8

2.5.2. Data for 4-phenylbenzaldehyde (7b). Yield: 0.151 g (83%). M.p. 89-91 °C. 1H NMR
(89.6 MHz, CDCl3) δH (ppm): 9.91 (s, 1H, CHO), 7.30- 7.86 (m, 9H, phenyl). 13C NMR
(100.62 MHz, CDCl3) δC (ppm): 191.91 (s, CO), 147.09, 139.60, 135.07, 130.21, 128.95, 128.41,
127.60, 127.29.
2.5.3. Data for biphenyl (7c). Yield: 0.107 g (70%). M.p. 67-69 °C. 1H NMR (89.6 MHz,
CDCl3) δH (ppm): 7.01-7.51 (m, 10H, phenyl). 13C NMR (100.62 MHz, CDCl3) δC (ppm):
141.29, 128.8, 127.30, 127.22.
2.5.4. Data for 4-methylbiphenyl (7d). Yield: 0.112 g (67%). M.p. 48–50 °C. 1H NMR
(89.6 MHz, CDCl3, ppm): δ = 7.25–7.60 (m, phenyl, 9H), 2.45 (s, CH3, 3H). 13C NMR
(100 MHz, CDCl3, ppm): δ = 141.1, 138.3, 136.9, 129.4, 130.1, 128.6, 126.9, 21.0.
2.5.5. Data for 4-methoxybiphenyl (7e). Yield: 0.112 g (61%). M.p. 90-92 °C. 1H NMR
(89.6 MHz, CDCl3) δH (ppm): 3.86 (s, 3H, OCH3), 6.93-7.50 (m, 9H, phenyl). 13C NMR
(100.62 MHz, CDCl3) δC (ppm): 159.19, 140.77, 133.69, 128.72, 128.20, 126.78, 114.18, 55.41.
2.5.6. Data for 4-acetyl-4ʹ-ethyl-biphenyl (7f). Yield: 0.168 g (75%). M.p. 105-108
°C.1H NMR (250.13 MHz, CDCl3) δH (ppm): 7.96- 7.18 (m, 8H, phenyl), 2.63 (q, CH2, 2H),
2.51 (s, CH3, 3H), 1.21 (t, CH3 (ethyl), 3H). 13C NMR (100.62 MHz, CDCl3) δC (ppm): 197.77,
145.75, 144.59, 137.20, 135.60, 128.91, 128.51, 127.20, 127.00, 28.58, 26.67, 15.56.
2.5.7. Data for 4-methyl-4ʹ-ethyl-biphenyl (7g). Yield: 0.119 g (61%). M.p. 59-61°C. 1H NMR
(89.6 MHz, CDCl3) δH (ppm): 7.29- 7.62 (m, 8H, phenyl), 2.69 (q, CH2, 2H), 2.47 (s, CH3, 3H),
1.36 (t, CH3 (ethyl), 3H). 13C NMR (100.62 MHz, CDCl3) δC (ppm): 143.02, 138.49, 138.26,
136.64, 129.40, 128.20, 126.85, 126.80, 28.47, 21.06, 15.60.
3. Results and discussion
3.1. Synthesis
The preparation of the phosphonium salts of dppm (S1) anddppe (S2)was carried out by reaction
of the corresponding diphosphine with 2-bromo-3ʹ-methoxy acetophenone. Further treatment
9

ofthese phosphonium salts with NEt3 led to elimination of HBr and formation of new
unsymmetricalphosphorus ylides Y1and Y2.Reaction of these ligands with [MCl2(COD)] (M= Pd
or Pt) in a 1:1 M ratio at room temperature afforded inall cases the PC chelated Pd(II) andPt(II)
complexes (see scheme 1).
O
O
Ph2
P
C
H2
CH2Br
Chloroform / 15 h
(CH2)n
PPh2(CH2)nPPh2
+
Br
Ph2P
n= 1 dppm
n= 2 dppe
OMe
OMe
S
S
(
(
1): n=1
2): n=2
O
NEt3
Ph2
P
H
C
n= 1
CH2
Cl
Cl
M
O
P
Ph2
Ph2
P
OMe
C
H
(CH2)n
3
M = Pd ( )
4
M = Pt ( )
MCl2(cod)
Ph2P
(
CH2Cl2 / 2 h
OMe
O
Y
1): n=1
2): n=2
Ph2
P
Y
(
H
C
CH2
CH2
n= 2
Cl
M
P
Ph2
Cl
OMe
5
M = Pd ( )
6
M = Pt ( )
Scheme 1. Synthesis of S1, S2, Y1, Y2and 3-6.
3.2. Spectroscopy
The structure of the products was characterized by 1H, 13C and 31P NMR spectroscopic methods
and other conventional techniques such as IR, UV–visible, fluorescence emission and elemental
analysis. Table 1 shows a brief summary of these data.
Also, the exact structure of 3and 6with atomic resolution wasdetermined by single crystal
X-ray diffraction. The CHN elemental analysis of the Pd(II) and Pt(II) complexes indicated a 1:1
stoichiometry between the MCl2 (M= Pd or Pt) and phosphorus ylide.
The ν(CO) band in the IR spectra of phosphorus ylides Y1and Y2were observed at lower
frequencies compared to the related phosphonium salts S1and S2, indicating formation of
P=Cdouble bond and decrease of C=O bond order. As noted previously [55], coordination of the
ylide through the carbon atom (chelating mode) or oxygen atom causes a significant increase or
10

decrease, respectively, in the ν(CO) frequency. Thus, the infrared absorption band for all
complexes at higher frequencies indicates that coordination of the ylideoccurs through ylidic
carbon atomand PPh2 group (see Supplementary Data) [21,56].
The 31P NMR spectra of S1and S2exhibit two doublets around 21, -29 and 24,-12
ppm,which are assigned to the PCH and PPh2groups, respectively. In 31P NMR spectra ofY1and
Y2, the phosphonium groups of these compounds show upfield shifts compared to thatof parent
phosphonium salts. These peaks were shifted to around 11, -29 and 17, -13 ppm,respectively(see
Supplementary Data). Furthermore, the 31Pchemical shift values for 3-6appear to be shifted
downfield with respect to the parentphosphorus ylides, indicating that coordination of the
ylidehas occurred.The 31P NMR spectra of Pd(II) complexes3and 5exhibit two doublets around
38, 28 and 30, 22 ppm, which can be assigned to the PPh2 and PCH groups, respectively. The
31P NMR spectra of Pt(II) complexes4and 6show these peaks around 42,4 and 20,6 ppm along
with two satellite peaks due to 195Pt-31P coupling (figure 1).
Also, the 1H NMRspectra of phosphorus ylides Y1and Y2show an upfield shift for the CH
signals compared to those ofphosphonium salts S1and S2, indicating that synthesis of the ylides
hasoccurred.Downfield shifts and broadening of the doublet signal were observed for the ylidic
proton in the 1H NMR spectra of 3-6 [42]. Similar behavior was observed earlier in the case of
ylide complexes of copper(I) chloride [12]. This signal for Pt(II) complexes is flanked by their
corresponding satellites due to coupling with the 195Pt isotope.
In the 13C NMR spectra of Y1and Y2, the signals due to the carbonyl group shiftedto
higher field compared to the parent phosphonium salts.The most important aspect of
the13C NMR spectra of 3-6is the downfield shift of the signals due to the carbonyl group. The
13C NMRspectra of the carbonyl group in these complexes are around 194 ppm, compared to 180
ppm for the same carbon in the parent free phosphorus ylides, indicating a much lower shielding
of the carbon of the CO group in these complexes (see Supplementary Data).Thus, the spectral
data clearly indicates the bidentate coordination of the ylides through both the phosphine group
and the ylidic carbon atom.
The palladium and platinum complexes have +2 oxidation states, indicating
diamagnetism. The electronic spectra at room temperature in DMSO solution of these complexes
show two bands at 300-500 nm. The electronic absorption spectra of these phosphorus ylides
11

showed spectral bands due to* and n* transitions. On complexation, these bands shift
toward higher wavelength (figure S1a and S1b in Supplementary Data).
The fluorescence emissions of all compounds were investigated at room temperature in
DMSO solution with a concentration 1×10-5 M. Complexes 3and5exhibited two weaker bands at
460 and 487 nm upon excitation at λex = 350 nm as well as one strong emission at 517 nm, as
illustrated in figure S2c in the Supplementary Data. The emission at 460 nm is due to the ligand
based intramolecular emission * (IL). Such a similar band was observed around 397 and
423 nm for a DMSO solution of the phosphorus ylides (λex = 350 nm (see figureS2b in
Supplementary Data). The broad emission band centered at 487 nm is assigned to the metal to
ligand charge transfer (MLCT). Also, emission spectra of a DMSO solution of 4and 6 upon
excitation at λex =350 nm have been shown in Supplementary Data. The first emission appeared
around 441 and 423 nm which is assigned to the * (IL) transition. The emission around 486
nm in these complexes is assigned to the d(Pt)* ligand (MLCT) upon excitation at λex = 350
nm (figure 2d in Supplementary Data).
3.3. Crystallography
Crystals, suitable for single-crystal X-ray analysis, of 3and 6 were grown by slow evaporation
over several days from DMSO/methanolsolution. The molecular structures of these
complexesare shown in figures2and 3. Relevant parameters concerning data collection and
refinement are given in table 2 and selected bond distances and angles for the unit cells are
displayed in table 3. Crystallographic data for the structure in this paper can be found in the
Supplementary Data.
The asymmetric unit of 3 contains two crystallographically independent palladacyclic
[PdCl2(Ph2P(CH2)PPh2C(H)C(O)C6H4-m-OMe)] molecules (figure 2).The only major difference
is in the orientation of the methoxy substituent on the aromatic ring; formolecule 1 the methoxy
substituent is oriented trans to the C=O group (O1-C2…C7-O2 179.0°), while for molecule 2 the
orientation is cis (O3-C36…C39-O4 -21.5°). The X-ray analysis in 3 reveals the P, C-chelated
mode of coordination of the ligand [Ph2P(CH2)PPh2C(H)C(O)C6H4-m-OMe] to the Pd(II) ion in
this complex. The Pd atom is surrounded by one P atom of the phosphine group, one ylidic
carbon and two chloride ions,leading to a slightly distorted square-planar geometry around the
metal.The angles subtended by the ligand at the Pd(II) center in 3 vary from 87.54(4) to
12

92.14(4) (sum of the angles is 360.14°) and 170.78(4) to 173.57(14), indicating the distortion
from the square planar environment.Weak C-H…Cl and C-H…O interactions link the molecules
along the c-axis (table S1 in Supplementary Data).
The asymmetric unit of 6 contains two crystallographically independentplatinacyclic
[PtCl2(Ph2P(CH2)2PPh2C(H)C(O)C6H4-m-OMe)] molecules (figure 3).In each the Pt is in an
approximately square planar environment, coordinated by twochloride ions and by one
phosphorus and one carbon atom from the ligand; for molecule 2 the maximum deviation from
the least squares plane is 0.0437(8) Å, while for molecule 1 the maximum deviation from the
least squares plane is 0.1568(8) Å, indicating a tetrahedral distortion.The major difference
between the molecules is in the conformation of the six-membered ring involving the Pt atom.
For the first molecule, the six-membered ring is in a chair conformation, while for the second
molecule, the six-membered ring is in a distorted half-boatconformation (four adjacent atoms
planar, with the other two adjacent atoms out of plane).Other geometric parameters for the two
molecules are similar, with only slight differences between the conformation of the two
molecules as evidenced by the torsion angles O1-C1-C2-Pt1 98.4(3)° and O3-C36-C37-Pt2
108.8(3)°. The angles subtended by the ligand at the Pt(II) center in 6 vary from 88.07(2).36 to
91.02(3) (sum of the angles is 360.14°) and 170.62(8)to 172.15(3), indicating the distortion
from the square planar environment.Both molecules have weak C-H...O and C-H…Cl
interactions; the intermolecular C-H…Cl interactions link the molecules along the b-
axis(table S2 in Supplementary Data). Although structures of six-membered palladacyclic ylide
complexes are known, a search of the Cambridge Structural Database (version 5.38, update Feb.
2017 [57]) indicated 6 to be the first example of a structure of a six-membered platinacycle ylide
complex.
3.4. Theoretical studies
A theoretical study on the structures and nature of L→M bonds in [LMCl2](M=Pd, Pt L=Y1, Y2)
complexes3-6is reported at the BP86 level of theory using the def2-SVP basis set. The X-ray
crystal structures obtained in this work(see figures 2 and 3) show that 3 formed monomeric P,C
chelate complexes with five-membered rings which lie in a square planar geometry around the
metal center.Also, this work and previous experimental data [58,59] confirm that upon
13

complexation of the Y1 and Y2 ligands, the monomeric P,C chelate complexes are formed as
five- and six-membered rings with a square planar geometry around the metal center.
The optimized structures of the [LMCl2](M=Pd, Pt, L=Y1, Y2) complexes are shown in
figure4 and the trends for variation of the corresponding structural data and their comparison
with experimental data are given intable 4.The results showed that changing the ligand from Y1to
Y2 and M atom from Pd to Pt have an insignificant effect on values of bond lengths of C→M and
P→M and the calculated and experimental C→M and P→M bond lengths in the complexes are
in ranges of 2.10−2.12Å and 2.21−2.25Å, respectively, On the other hand, the Cl−M−Cl bond
angle in five-membered ring complexes are greater than six-membered rings complexes (see
figure 4 and table 4).The nature ofL→M bonds in [LMCl2](M=Pd, Pt,L=Y1, Y2) complexes(3-
6)have been investigated by NBO and energy decomposition analysis (EDA).
The partial charge amounts of the P, C(ylide) and M atoms ofC→M and P→M bonds in the
complexes and also the total charge amounts of the MCl2fragment (M=Pd, Pt) were also
investigated (see table 5). Concerning [LMCl2] complexes, the P atom of the P→M bond carry
positive charges, but the C(ylide) and MCl2 fragment carry negative charges[60]. Also the amount
of negative charge of C(ylide) in [Y1MCl2] (3-4)complexes are slightly larger than that in
[Y2MCl2](5-6).
The Wiberg bond indices (WBIs) for C→M and C→P bonds of [LMCl2] (M=Pd,
Pt,L =Y1, Y2) complexes(3-6)are also compared in table 5. As can be seen, the value of WBI of
C→P bond in the complexes is larger than C→M bond. Also with the same L ligand and
changing the M atoms from Pd to Pt, the values of WBIs of C→M and C→P bonds in the
complexes are increased.
In recent years, Morokuma [60] and Ziegler et al.[61] presented the "energy
decomposition analysis" (EDA) method. With the help of this technique, a quantitative
computational pattern for the explanation of the strength of M←L σ donation and M→L back
bonding in the main group and transition metal complexes with different types of ligands is in
hand [62-71].
In continuation, through the energy decomposition analyses (EDA), the strength and
nature of donor−acceptor bonds between the phosphorus ylides (L) and MCl2 fragment have
been investigated at BP86/TZ2P(ZORA)//BP86/def2-SVP with C1 symmetry using the program
package ADF2009.01.
14

The results of EDA analyses for all aforementioned complexes are given in table 6. In the
EDA, the bonding formation of interacting fragments would result from four main components
as follows:
where is electrostatic interaction, is Pauli repulsion, is orbital interaction and is
dispersion energy between two fragments.The result of EDA analysis confirmsthat the main
portions of , about 56-58% in the complexes are allocated to (see table 6).
Also, the visualizations of the NOCV pairs (∆ρ) between the donor orbitals of
phosphorus ylides (L) and the acceptor orbitals of MCl2 fragment are shown in figures5 and 6.
As can be seen, the dominant term of for all aforementioned complexes arises from σ-orbital
interactions (∆ρ1, ∆ρ2 and ∆ρ3). The calculated data show that the σ-orbital interactions account
for 70.69- 75.29% of the term for studied complexes. Also, the shapes of the orbital pairs of
∆ρ3 and ∆ρ4 refer to π back-donations which are in-plane and out-of-plane, respectively, and
account for about 9.63-10.87% of the term (see table 6 and figures 5 and 6).
3.5. Suzuki reaction of aryl bromide
In order to examine the catalytic activity of Pd(II) complexes in the Suzukireaction, the reaction
between bromobenzene with phenylboronic acid in the presence of catalyst 3 was chosen as
model reaction.Influences of different parameters such as base, temperature, solvent and catalyst
concentration were examined to obtain the best possible combination.
At the first stage of optimization, we studied the effect of base and solvent on the
reaction. Since the solubility and basicity of base strongly depend on the solvent used, these two
parameters are closely connected. This optimization was done with commonly used bases and
solvents, including organic and inorganic bases and aqueous protic and aprotic solvents.
Coupling reactions carried out in the presence of K3PO4and K2CO3give the desired coupling
product in moderate to high yields (table 7, entries 1, 4 and 2, 5). However, the reactions in the
presence of NEt3did not proceed efficiently even after prolonged stirring at reflux temperature of
the solvents, probably due to the low solubility of this organic base in aqueous solvents(table 7,
entries 3, 6 and 9). Among the tested aqueous solvents, DMF/H2O gave higher yields of coupled
15

product. Also, the reactions in water and non-aqueous DMF led to lower yields, indicating the
important role of the solubility of the base in such catalytic systems (table 7, entries 10 and 11).
During the optimization process,we investigated the effect of catalyst loading on the
reaction. As expected, varying the catalyst loading has a significant effect on the performance of
the catalyst. When the loading of 3 decreased to 0.005 mmol, the coupling reaction gave slightly
lower product yield and the reaction resulted in negligible yield of coupled product when the
catalyst loading decreased to 0.0005 mmol (table 7, entries 12 and 13). Also, an excessive
amount of catalyst did not increase the yield significantly (table 7, entry 14). Therefore, with
respect to the economic aspect, 0.005 mmol of catalyst was chosen as the best catalyst
loading.Finally, the reactions were carried out at different temperatures. Decreasing the
temperature of the reactions led to a decrease of the yields and inherent increase of the reaction
time for completion of the reactions (table 7, entries 15 and 16).
The optimized conditions are:DMF/H2O as solvent, K2CO3 as base, 0.005 mmol of 3 as
catalyst and reaction at reflux temperature (110 °C) for 6 h.
After optimizing the reaction conditions, the scope of the reaction was explored with aryl
bromides with electron-withdrawing and electron-donating groups and phenylboronic acid. The
results are summarized in table 8. As illustrated in table 8, aryl bromides were converted into the
corresponding coupled products in high yields. Conversely, increasing electron density on the
aryl bromides lowered the catalyst activity. That is, excellent yields are achieved when
phenylboronic acidis treated with aryl bromides bearing electron-withdrawing substituentsNO2, –
CHO and -COCH3(table 8, entries 1-3). Deactivated aryl bromides 4-bromotoluene and
4-bromoanisol gave lower yields, indicating that the reaction was sensitive to the electron density
on the aryl bromides (table 8, entries 5 and 6).The reaction of electronically neutral
bromobenzene with phenylboronic acid was also produced good amounts of the product (table 8,
entry 4).As seenin table 8, we observed that in all cross-coupling reactions, 3and 5had
approximatelythe same catalytic activities and similar yields.
To extend the scope of our work, we investigated the coupling reaction of aryl
bromidesubstrates with ethyl substituted phenylboronic acid. As expected, an electron-donating
substituenton the arylboronic acid has adecreasing effect on the yield of the reaction (table 8,
entries 7-10).However, the coupling reaction of activated aryl bromides such as
16

4-phenylbenzaldehydegave thecoupled boronic acid derivatives in higher yields (table 8,
entry 11).
Table 9 shows a comparison between theefficiency of this catalytic system in the Suzuki
reaction of aryl bromides andother catalytic systems. The results of this comparison showed that
the reported catalysts inliterature need to be used in high loadings and showed lower activity
with aryl bromidesubstrates [72-75]. From an industrial point of view, the low catalyst loading
and short reactiontime make this Pd complex an ideal catalyst for the Suzuki reaction.
4. Conclusion
The present study describes the very simple and efficient synthesis and characterization of new
phosphonium salts, phosphorus ylides and a series of P–C chelated Pd(II) and Pt(II)complexes.
On the basis of the spectroscopic data, we have proposed that ligands herein exhibit a chelate
PC coordination behavior to the metal center affording a five- or six-membered chelate
rings.This coordination fashion has beenfurther confirmed by single crystal X-ray diffraction
experiments of 3and6. Also, we used 3 and 5 as highly active and efficient catalysts for
promoting the Suzuki reaction of various aryl bromides to produce the corresponding products in
high yields. Results showed that the coupling reaction of various aryl bromides with arylboronic
acid was performed in high yields.The theoretical studies on the structures and nature of L→M
bonds in [LMCl2] (M= Pd, Pt, L= Y1, Y2) complexes are reported by using NBO, EDA and
EDA-NOCV analysis. The results of NBO analysis confirmed that the value of WBI of C→P
bond in the latter complexes is larger than C→M bond. Also with the same L ligand and
changing the M atoms from Pd to Pt, the values of WBIs of C→M and C→P bonds in the
complexes increased. The result of EDA analysis confirms that the main portions of , about 56-
58% in the complexes are allocated to . Also the NOCV pairs (∆ρ) between the donor orbitals
of phosphorus ylides (L) and the acceptor orbitals of MCl2 fragment showed that the dominant
term of for all aforementioned complexes arises from σ-orbital interactions (about70.69-
75.29%).
17

Supplementary material
Supplementary data (CCDC 1475346 - 1547211 contain the supplementary crystallographic data
for 3and6).These data can be obtained free of charge via www.ccdc.cam.ac.uk/data_request/cif
or from the Cambridge Crystallographic Data Center, 12 Union Road, Cambridge CB2 1EZ, UK;
Tel.: +44 0 1223 762911; or E-mail: deposit@ccdc.cam.ac.uk.
Acknowledgements
Funding of our research from the Bu-Ali Sina University is gratefully acknowledged.
References
[1]
[2]
W.C.Kaska.Coord. Chem. Rev.,48, 1 (1983).
U.Belluco, R.A.Michelin, M.Mozzon, R.Bertani, G.Facchin, L.Zanotto, L.Pandolfo.
J.Organomet. Chem., 557,37 (1998).
[3]
L.R.Falvello, S.Fernandez, R.Navarro, A. Rueda, E.P.Urriolabeitia. Inorg. Chem.,37,
6007(1998).
[4]
[5]
E.P. Urriolabeitia.Dalton Trans.,5673 (2008).
S.J. Sabounchei, S. Samiee, S. Salehzadeh, M. Bayat, Z.B. Nojini, D. Morales-
Morales.Inorg. Chim. Acta,363, 1254 (2010).
[6]
[7]
[8]
[9]
S.J. Sabounchei, M. Pourshahbaz, R. Karamian, M. Asadbegy. J. Chem. Res.,38, 192
(2014).
S.J. Sabounchei, M. Pourshahbaz, S. Salehzadeh, M. Bayat, R. Karamian, M. Asadbegy,
H.R. Khavas.Polyhedron,85, 652 (2015).
J. Buckle, P.G. Harrison, T.J. King, J.A. Richards.J. Chem. Soc., Chem. Commun.,19,
1104 (1972).
J.A. Albanese, D.L. Staley, A.L. Rheingold, J.L. Burmeister.Inorg. Chem., 29, 2209
(1990).
[10]
[11]
[12]
[13]
S.M. Sbovata, A. Tassan, G. Facchin. Inorg. Chim. Acta, 361, 3177 (2008).
L.R. Falvello, S.Fernandez, R. Navarro, E.P. Urriolabeitia.Inorg. Chem.,39, 2957 (2000).
A. Spannenberg, W. Baumann, U. Rosenthal. Organometallics,19, 3991 (2000).
L.R. Falvello, M.E. Margalejo, R. Navarro, E.P. Urriolabeitia.Inorg. Chim. Acta, 347, 75
(2003).
18

[14]
[15]
[16]
[17]
[18]
[19]
M.M. Ebrahim, K. Panchanatheswaran, A. Neels, H. Stoeckli-Evans.J. Organomet.
Chem.,694, 643 (2009).
D. Saravanabharathi, T.S. Venkatakrishnan, M. Nethaji, S.S. Krishnamurthy.Proc. Indian
Acad. Sci. (Chem. Sci.),115, 741 (2003).
S.J.Sabounchei, M. Pourshahbaz, A. Hashemi, M. Ahmadi,R. Karamian, M. Asadbegy,
H.R. Khavas. J. Organomet. Chem., 761, 111 (2014).
S.J. Sabounchei, M. Pourshahbaz, M. Ahmadi, A. Hashemi,H.R. Khavas. Inorg. Chem.
Commun.,36, 39 (2013).
S.J. Sabounchei, M. Ahmadi, M. Panahimehr, F. Akhlaghi Bagherjeri, Z. Nasri. J. Mol.
Catal. A: Chem.,383-384, 249 (2014).
D. Soulivong, C. Wieser, M. Marcellin, D. Matt, A. Harriman, L. Toupet.J. Chem.
Soc.,Dalton Trans., 13, 2257 (1997).
[20]
[21]
M.M. Ebrahim, H. Evans, K. Panchanatheswaran.Polyhedron,26, 3491 (2007).
S.J. Sabounchei, S. Samiee, D. Nematollahi, A. Naghipour, D. Morales-Morales.
Inorg.Chim. Acta,363, 3973 (2010).
[22]
[23]
S.J. Sabounchei, M. Ahmadi. Catal. Commun.,37, 114 (2013).
D.L. Dodds, M.D.K. Boele, G.P.F. van Strijdonck, J.G. de Vries, P.W.N.M. van
Leeuwen, P.C.J. Kamer.Eur. J. Inorg. Chem.,10, 1660 (2012).
S.J. Sabounchei, M. Hosseinzadeh. J. Chem. Sci.,127, 1919 (2015).
A. Ghorbani-Choghamarani, A. Naghipour, H. Babaee, B. Notash.Polyhedron,119, 517
(2016).
[24]
[25]
[26]
[27]
[28]
B.L. Shaw, S.D. Perera.Chem. Commun.,17, 1863 (1998).
S.J. Sabounchei, M.Ahmadi.Inorg. Chim. Acta, 405, 15 (2013).
S.J. Sabounchei, M. Panahimehr, M. Ahmadi, Z. Nasri, H.R. Khavasi.J. Organomet.
Chem.,723, 207 (2013).
[29]
S.J. Sabounchei, M. Panahimehr, M. Ahmadi, F. Akhlaghia, C. Boscovic.C.R. Chim., 17,
81 (2014).
[30]
[31]
S.J. Sabounchi, M. Ahmadi, T. Azizi, M. Panahimehr. Synlett.,25, 336 (2014).
S.J. Sabounchei, M. Ahmadi, Z. Nasri, E. Shams, S. Salehzadeh, Y. Gholiee, R.
Karamian,M. Asadbegy, S. Samiee.C. R. Chim.,16, 159 (2013).
19

[32]
[33]
(a) A. Suzuki.Pure Appl. Chem.,57, 1749 (1985). (b) A. Suzuki. Pure Appl. Chem., 66,
213 (1994). (c) J. Zhang, L. Zhao, M. Song, T.C.W. Mak, Y. Wu.J. Organomet.
Chem.,691, 1301 (2006).
R.S. Martin, B. Inés, M.J. Moure, M.T. Herrero, E. Domínguez.Helv. Chim. Acta,95, 955
(2012).
[34]
[35]
[36]
[37]
S.D. Dindulkar, D. Jeong, H. Kim, S. Jung.Carbohydr. Res.,430,85 (2016).
M. Waheed, N. Ahmed.Tetrahedron Lett.,57, 3785 (2016).
D. Drew, J.R. Doyle, A.G. Shaver.Inorg. Synth.,13, 47 (1972).
A.J. Gordon, R.A. Ford, The Chemist’s Companion: A Handbook of Practical Data,
Techniques and References, Wiley-Interscience, New York,438 (1972).
CrysalisPro 1.171.38.41 (for 3) and 1.171.38.43i (for 6), Rigaku Oxford Diffraction
(2015).
[38]
[39]
O.V. Dolomanov, L.J. Bourhis, R.J. Gildea, J.A.K. Howard, H. Puschmann.J.
Appl.Cryst.,42, 339 (2009).
[40]
[41]
[42]
[43]
[44]
[45]
G.M. Sheldrick.Acta Cryst. A, 71, 3 (2015).
G.M. Sheldrick. Acta Cryst. A,64, 112 (2008).
A.D. Becke.Phys. Rev. A,38, 3098 (1988).
J.P. Perdew.Phys. Rev. B,33, 8822 (1986).
A. Schäfer, C. Huber, R. Ahlrichs.J. Chem. Phys.,100, 5829 (1994).
S.J. Sabounchei, M. Sarlakifar, S. Salehzadeh, M. Bayat, M. Pourshahbaz, H.R.
Khavasi.Polyhedron,38, 131 (2012).
[46]
[47]
S.J. Sabounchei, H. Nemattalab, S. Salehzadeh, S Khani, M. Bayat, H.R. Khavasi.
Polyhedron, 27, 2015 (2008).
M. Bayat, M. von Hopffgarten, S. Salehzadeh, G. Frenking. J. Organomet. Chem.,696,
2976 (2011).
[48]
[49]
[50]
[51]
M. Bayat, S. Salehzadeh, G. Frenking. J. Organomet. Chem.,697, 74 (2012).
M. Bayat, N. Ahmadian.Polyhedron,96, 95 (2015).
M. Bayat, N. Ahmadian. J. Iran. Chem. Soc.,13, 397 (2016).
S.J. Sabounchei, M. Ahmadianpoor, A. Yousefi, A. Hashemi, M. Bayat, A. Sedghi,
F.Akhlaghi Bagherjeri, R.W. Gable.RSC Adv., 6, 28308 (2016).
20

[52]
[53]
S.J. Sabounchei, A. Yousefi, M. Ahmadianpoor, A. Hashemi, M. Bayat, A. Sedghi,
F.A.Bagherjeri, R.W. Gable.Polyhedron,117, 273 (2016).
M.J. Frisch, G.W. Trucks, H.B. Schlegel, G.E. Scuseria, M.A. Robb, J.R. Cheeseman,G.
Scalman, V. Barone, B. Mennucci, G.A. Petersson, H. Nakatsuji, M. Caricato, X. Li,
H.P.Hratchian, A.F. Izmaylov, J. Bloino, G. Zheng, J.L. Sonnenberg, M. Hada, M. Ehara,
K.Toyota, R. Fukuda, J. Hasegawa, M. Ishida, T. Nakajima, Y. Honda, O. Kitao, H.
Nakai, T.Vreven, J.A. Montgomery Jr., J.E. Peralta, F. Ogliaro, M. Bearpark, J.J. Heyd,
E. Brothers, K.N. Kudin, V.N. Staroverov, R. Kobayashi, J. Normand, K. Raghavachari,
A. Rendell, J.C.Burant, S.S. Iyengar, J. Tomasi, M. Cossi, N. Rega, J.M. Millam, M.
Klene, J.E. Knox, J.B.Cross, V. Bakken, C. Adamo, J. Jaramillo, R. Gomperts, R.E.
Stratmann, O. Yazyev, A.J.Austin, R. Cammi, C. Pomelli, J.W. Ochterski, R.L. Martin,
K. Morokuma, V.G. Zakrzewski,G.A. Voth, P. Salvador, J.J. Dannenberg, S. Dapprich,
A.D. Daniels, Ö. Farkas, J.B.Foresman, J.V. Ortiz, J. Cioslowski, D.J. Fox, Gaussian 09,
Revision A.02, Gaussian, Inc.,Wallingford, CT (2009).
[54]
[55]
E.D. Gladdening, A.E. Reed, J.A. Carpenter, F. Weinhold, NBO Version 3.1.
M. Kalyanasundari, K. Panchanatheswaran, W.T. Robinson, H. Wen. J. Organomet.
Chem.,491, 103 (1995).
[56]
[57]
[58]
M.M. Ebrahim, H. Stoeckli-Evans, K. Panchanatheswaran.Polyhedron,26, 3491 (2007).
C.R. Groom, I.J. Bruno, M.P. Lightfoot, S.C. Ward. Acta Cryst., B72, 171 (2016).
H. Keypour, N. Rahpeyma, M. Rezaeivala, P. Arzhangi, M. Bayat, L. Valencia, Y.
Elerman, O. Büyükgüngör. Polyhedron,51, 117 (2013).
[59]
H. Keypour, A. Shooshtari, M. Rezaeivala, M. Bayat, H. Amiri Rudbari. Inorg. Chim.
Acta, 440, 139 (2016).
[60]
[61]
[62]
[63]
K. Morokuma. J. Chem. Phys., 55, 1236 (1971).
T. Ziegler, A. Rauk. Theor. Chim. Acta, 46, 1 (1977).
M. Bayat, A. Sedghi, L. Ebrahimkhani, S.J. Sabounchei. Dalton Trans.,46, 207 (2017).
H. Keypour, M. Rezaeivala, A. Ramezani-Aktij, M. Bayat, N. Dilek, H. Ünver.Mol.
Struct.,1115, 180 (2016).
[64]
[65]
M. Bayat, M. Hatami. Polyhedron, 110, 46 (2016).
H. Keypour, M. Liyaghati-Delshad, M. Rezaeivala, M. Bayat. J. Iran. Chem. Soc., 12,
621 (2015).
21

[66]
S.J. Sabounchei, S. Samiee, M. Pourshahbaz, S. Salehzadeh, M. Bayat, D. Nematollahi,
R. Karamian, M. Asadbegy.J. Chem. Res.,38, 35 (2014).
[67]
[68]
[69]
S. Salehzadeh, M. Khalaj, S. Dehghanpour, M. Bayat. J. Iran. Chem. Soc.,11, 9 (2014).
M. Bayat, F. Amraie, S. Salehzadeh. J. Theor. Comput. Chem., 15, 16500032 (2016).
G. Frenking, K. Wichmann, N. Fröhlich, C. Loschen, M. Lein, J. Frunzke, V.C.M.
Rayón. Coord. Chem. Rev.,238–239, 55 (2003).
[70]
[71]
[72]
[73]
M. Lein, A. Szabo, A. Kovacs, G. Frenking. Faraday Discuss.,124, 365 (2003).
M. Bayat, E. Soltani. Polyhedron,123,39 (2017).
T.M. Shaikh, F.-E. Hong.Beilstein J. Org. Chem., 9, 1578 (2013).
J. Silberg, T. Schareina, R. Kempe, K. Wurst, M.R. Buchmeiser.J. Organomet. Chem.,
622, 6 (2001).
[74]
[75]
A. Ataei, S. Nadri, E. Rafiee, S. Jamali, M. Joshaghani.J. Mol. Catal. A: Chem.,366, 30
(2013).
S.M. Islam, P. Mondal, K. Tuhina, A.S. Roy, S. Mondal, D. Hossain. J. Inorg.
Organomet.Polym., 20, 264 (2010).
22

Graphical abstract
23

24

25

26

27

28

29