Organophosphorus ligands with XPNSO skeleton (X = O, S) and their Pd(II) complexes. Crystal and molecular structure of [{XP(OEt)2}(O 2SR)]NH (X = O, R = Me, Ph; X = S, R = C6H 4Cl-4) and Pd[{SP(OEt)2}(O2SC6H 4Cl-4)N]2

Article abstract of DOI:10.1016/j.poly.2013.01.023

Several organophosphorus acids of type [{XP(OEt)₂}(O ₂SR)]NH [X = O, R = Me (1), Ph (2), C₆H₄CH ₃-4 (3); X = S, R = C₆H₄Cl-4 (4)] were obtained by a method based on the reaction between (EtO)₂P(X)NHLi and the corresponding organosulfonyl chloride. They were subsequently deprotonated with KOBu^t. Salt metathesis reactions between PdCl₂ and the corresponding potassium salts K[{XP(OEt)₂}(O₂SR)N] [X = O, R = Me (5), Ph (6), C₆H₄CH₃-4 (7); X = S, R = C₆H₄Cl-4 (8)] in a 1:2 molar ratio resulted in palladium(II) complexes of type Pd[{XP(OEt)₂}(O₂SR)N] ₂ [X = O, R = Me (9), Ph (10), C₆H₄CH ₃-4 (11); X = S, R = C₆H₄Cl-4 (12)]. In a similar way was obtained the palladium(II) complex Pd[(SPPh₂)(O ₂SPh)N]₂ (13), using the appropriate reagents. All compounds were characterized by multinuclear NMR (¹H, ¹³C, ³¹P) and infrared spectroscopy. The potassium salts and the palladium complexes were investigated also by mass spectrometry. Single-crystal X-ray diffraction studies revealed a layered supramolecular assembly in case of acid 1, a monomeric structure for compound 4, while in case of compound 2 dimeric associations are formed in the solid state by NH?OP hydrogen bonding. A trans-S,N-coordination pattern of the organophosphorus ligand was found in the palladium complex 12. Moreover, short Cl?H contacts result in a polymeric [Pd[{SP(OEt)₂}(O₂SC₆H ₄Cl-4)N]₂]_n chain.

Full text of DOI:10.1016/j.poly.2013.01.023

Polyhedron 53 (2013) 67–75
Contents lists available at SciVerse ScienceDirect
Polyhedron
journal homepage: www.elsevier.com/locate/poly
Organophosphorus ligands with XPNSO skeleton (X = O, S) and their Pd(II)
complexes. Crystal and molecular structure of [{XP(OEt)2}(O2SR)]NH
(X = O, R = Me, Ph; X = S, R = C6H4Cl-4) and Pd[{SP(OEt)2}(O2SC6H4Cl-4)N]2
⇑
Dorel Oltean, Alpar Pöllnitz, Anca Silvestru
Faculty of Chemistry and Chemical Engineering, Babes-Bolyai University, RO-400028 Cluj-Napoca, Romania
a r t i c l e i n f o
a b s t r a c t
Article history:
Several organophosphorus acids of type [{XP(OEt)2}(O2SR)]NH [X = O, R = Me (1), Ph (2), C6H4CH3-4 (3);
X = S, R = C6H4Cl-4 (4)] were obtained by a method based on the reaction between (EtO)2P(X)NHLi and
the corresponding organosulfonyl chloride. They were subsequently deprotonated with KOBut. Salt
metathesis reactions between PdCl2 and the corresponding potassium salts K[{XP(OEt)2}(O2SR)N]
[X = O, R = Me (5), Ph (6), C6H4CH3-4 (7); X = S, R = C6H4Cl-4 (8)] in a 1:2 molar ratio resulted in palla-
dium(II) complexes of type Pd[{XP(OEt)2}(O2SR)N]2 [X = O, R = Me (9), Ph (10), C6H4CH3-4 (11); X = S,
R = C6H4Cl-4 (12)]. In a similar way was obtained the palladium(II) complex Pd[(SPPh2)(O2SPh)N]2
(13), using the appropriate reagents. All compounds were characterized by multinuclear NMR (1H, 13C,
31P) and infrared spectroscopy. The potassium salts and the palladium complexes were investigated also
by mass spectrometry. Single-crystal X-ray diffraction studies revealed a layered supramolecular assem-
bly in case of acid 1, a monomeric structure for compound 4, while in case of compound 2 dimeric asso-
ciations are formed in the solid state by NHꢀ ꢀ ꢀOP hydrogen bonding. A trans-S,N-coordination pattern of
the organophosphorus ligand was found in the palladium complex 12. Moreover, short Clꢀ ꢀ ꢀH contacts
result in a polymeric [Pd[{SP(OEt)2}(O2SC6H4Cl-4)N]2]n chain.
Received 20 September 2012
Accepted 24 January 2013
Available online 4 February 2013
Keywords:
Organophosphorus ligands
Palladium complexes
Structure elucidation
Ó 2013 Elsevier Ltd. All rights reserved.
1. Introduction
odichalcogenoimidodiphosphinato ligands were investigated as
active species in different organic transformations [13–16,32].
For long time tetraorganodichalcogenoimidodiphosphinato li-
gands of type (XPR2)(YPR02)Nꢁ (A) (Scheme 1) (X, Y = O, S, Se, Te;
R, R0 = alkyl, aryl, alkoxy, aryloxy) were systematically investigated,
mainly due to their versatility towards main group or transition
metals, their coordination ability being determined by the high
flexibility of the XPNPY skeleton, as well as by their tendency to
form chelate rings with different conformations, as a consequence
of their bidentate behavior. The free acids, as well as their metal
complexes were extensively discussed in several papers [1–9].
Such species proved to be good candidates for applications in
different fields, i.e. selective metal extraction [10–12], catalysis
[13–16], materials science [4,17–20] or as NMR shift reagents [21].
On the other hand, several bis(organosulfonyl)imides, (O2SR)
(O2SR0)NH, were investigated, either in their protonated or depro-
tonated form (B) (Scheme 1), as ligands towards metal centers [22–
31].
The tetraorganodichalcogenoimidodiphosphinato ligands was ob-
served to have different coordination patterns towards Pd(II), due
to the different steric and electronic effects determined by
the substituents at the phosphorus atoms, including here the
different combinations of organic groups and chalcogens. The
complexes containing symmetric organophosphorus moieties, i.e.
Pd[(XPR2)2N]2, and most of the asymmetrically substituted species
Pd[(XPR2)(YPR02)N]2 (X – Y, X, Y = O, S, Se; R, R0 = alkyl, aryl) usu-
ally form two non-planar six-membered metallacycles with differ-
ent conformations, involving a X,Y-monometallic biconnective
coordination pattern and a square planar coordination geometry,
i.e. in Pd[(SPMe2)2N]2, cis-Pd[(OPPh2)(SPMe2)N]2 [33], Pd[(SPPh2)2-
N]2 [34], trans-Pd[(SPPh2){SP(OEt)2}N]2 [35], while few complexes
were found to display a S,N-monometallic biconnective coordina-
tion, i.e. trans-Pd[{OP(OPh)2}{SP(OPh)2}N]2 [36] and trans-
Pd[{OP(OPh)2}(SPR2)N]2 (R = Ph, Pri) [37]. If an additional chelating
ligand (i.e. ethylene diamine) is also present, the imidodichalco-
Palladium(II) complexes with organophosphorus ligands still
attract
a
continuous interest mainly due to the catalytic
geno ligand behaves as a Y-monodentate moiety, i.e. in
properties of palladium, and several derivatives with tetraorgan-
(en)Pd[(OPPh2)(YPPh2)N]2 (Y = S, Se) [38,39]. A monodentate bime-
tallic biconnective (bridging) coordination pattern was found in
[Pd(g
3-C3H5){Ph2P(O)NP(E)Ph2}]2 (E = S, Se) [9].
Recently we reported the synthesis and structural characteriza-
⇑
Corresponding author. Tel.: +40 264 593833; fax: +40 264 590818.
E-mail address: ancas@chem.ubbcluj.ro (A. Silvestru).
tion of several organophosphorus acids of type (XPR2)(O2SR0)NH
0277-5387/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved.
http://dx.doi.org/10.1016/j.poly.2013.01.023

68
D. Oltean et al. / Polyhedron 53 (2013) 67–75
the organic phase the solvent was removed under vacuum and ap-
prox. half of the initial (EtO)2P(O)NH2 was recovered (1.06 g). The
aqueous phase was treated with HCl 0.5 N and the resulting solid
product was separated by suction filtration and dried in vacuum.
Recrystallisation from a chloroform/n-hexane mixture (1/4, v/v)
gave the title compound as
1.263 g (78%). M.p. 93–4 °C. Anal. Calc. for C5H14NO5PS (MW
a microcrystalline solid. Yield:
Scheme 1.
231.20): C, 25.97; H, 6.10; N, 6.06. Found: C, 25.88; H, 6.07; N,
6.14%. 1H NMR (CDCl3): d 1.41 (t, 6H, CH3CH2, JHH 7.1 Hz), 3.19
3
(C) (Scheme 1) (X = S, R = Ph, R0 = Me, Ph, C6H4CH3-4; X = O,
R = R0 = Ph), as well as their sodium or potassium salts and several
group 11 metal complexes [40–42].
3
3
(s, 3H, CH3S), 4.27 (dq, 4H CH3CH2, JHH 7.3, JPH 7.3 Hz), 8.36 (s,
3
br., 1H, NH). 13C NMR: d 15.95 (d, OCH2CH3, JPC 7.4 Hz), 42.71 (s,
2
SCH3), 64.68 (d, OCH2CH3, JPC 5.9 Hz), 31P NMR: d ꢁ5.06s. FT-IR
Several methods of synthesis were reported before for related
ligands of type [{XP(OEt)2}(O2SR)]NH (X = O, R = Ph, C6H4CH3-4;
X = S, R = C6H4Cl-4): (i) by the phosphorylation of primary sulfona-
mides with dialkylchlorophosphates [43–46], (ii) the reaction of
sodium salts of secondary phosphoramidates with alkyl- or aryl
sulfonyl chlorides [47], (iii) by phosphorylation of primary sulfon-
amides with PCl5 followed by alcoholysis [48,49], or (iv) by the
reaction between HP(O)OEt and PhSO2NH2 in the presence of
NaOH 50% and catalytic amounts of hexadecyltributylphosphoni-
um bromide [50]. However, the compounds were not fully charac-
terized till now.
As a continuation of our studies, we report here about the syn-
thesis and structural characterization of several ligands of type
[{XP(OEt)2}(O2SR)]NH [X = O, R = Me (1), Ph (2), C6H4CH3-4 (3),
X = S, R = C6H4Cl-4 (4)], as well as their potassium salts
K[{XP(OEt)2}(O2SR)N] [X = O, R = Me (5), Ph (6), C6H4CH3-4 (7);
X = S, R = C6H4Cl-4 (8)] and their palladium(II) complexes. The pal-
ladium(II) complex Pd[(SPPh2)(O2SPh)N]2 is also described.
(cmꢁ1):
1155vs,
m
(NH) 2762 m,
m
(P@O) 1240s,
mas(SO2) 1248s, mas(PNS)
m
s(SO2) 1022vs,
m
(POC) 983s, mas[PN(H)S] 927s.
Compounds 2–4 were prepared similarly.
[{OP(OEt)2}(O2SPh)]NH (2), from n-BuLi in n-hexane (11.94 mL
1.6 M, 19.11 mmol), (EtO)2P(O)NH2 (2.924 g, 19.11 mmol) and
PhSO2Cl (1.686 g, 9.55 mmol). Yield: 2.574 g (92%). M.p. 108 °C
(Lit. [44] 111 °C). Anal. Calc. for C10H16NO5PS (MW 293.27): C,
40.95; H, 5.50; N, 4.78. Found: C, 40.70; H, 5.45; N, 4.77%. 1H
NMR (CDCl3): d 1.22 (t, 6H, CH3CH2, 3JHH 7.01 Hz); 4.03 (ABXY3 spin
3
2
3
system with dA 3.97 and dB 4.09 ppm, JHH 6.9, JHH 10.0, JPH 7.9
3
and 7.6 Hz, 4H CH3CH2), 7.49 (t, 2H, C6H5-meta, JHH 7.5 Hz), 7.5
3
3
(t, 1H, C6H5-para, JHH 7.2 Hz), 7.96 (d, 2H, C6H5-ortho, JHH
7.5 Hz). The resonance for the NH proton was not observed. 13C
3
NMR (CDCl3): d 15.81 (d, CH2CH3, JPC 7.5 Hz), 64.42 (d, CH2CH3,
2JPC 5.5 Hz), 127.12 (s, C6H5-ortho), 128.83 (s, C6H5-meta), 133.06
(s, C6H5-para), 141.12 (s, C6H5-ipso). 31P NMR: d ꢁ5.40s. FT-IR
(cmꢁ1):
1175vs,
m
(NH) 2717s,
m
(P@O) 1232s,
m
as(SO2) 1245vs,
mas(PNS)
m
s(SO2) 1025s,
m
(POC) 975s,
mas[PN(H)S] 935s.
[{OP(OEt)2}(O2SC6H4CH3-4)]NH (3), from n-BuLi in n-hexane
(11.95 mL 1.6 M, 19.15 mmol), (EtO)2P(O)NH2 (2.93 g,
2. Experimental
19.15 mmol) and 4-CH3C6H4SO2Cl (1.824 g, 9.575 mmol). Yield:
2.44 g (83%). M.p. 103 °C (Lit. [43] 104 °C). Anal. Calc. for C11H18-
NO5PS (MW 307.30): C, 42.99; H, 5.90; N, 4.56. Found: C, 43.11;
2.1. General methods
3
H, 5.92; N, 4.59%. 1H NMR (CDCl3): d 1.26 (t, 6H, CH3CH2, JHH
Starting materials, i.e. RSO2Cl (R = Me, Ph, C6H4CH3-4, C6H4Cl-4),
(EtO)2P(X)NH2 (X = O, S), KOBut and PdCl2 were used as purchased
(Aldrich). K[(SPPh2)(O2SPh)N] was obtained as reported previously
[41]. The solvents were dried and freshly distilled under argon
prior to use. Elemental analyses were performed on a Flash EA
1112 machine and melting points were measured on an Electro-
thermal 9200 apparatus and they are not corrected. Infrared spec-
tra were recorded in the range 4000–400 cmꢁ1 on a Jasco FTIR-615
machine, as KBr pellets, while mass spectra (APCI or ESI MS) were
performed on a LTQ Orbitrap – XL instrument. 1H, 13C and 31P NMR
spectra were recorded on a BRUKER Avance DRX 300 instrument.
The chemical shifts are reported in d units (ppm) relative to the
residual peak of the deuterated solvent (ref. CHCl3: 1H 7.26 ppm,
13C 77.0 ppm, DMSO: 1H 2.50 ppm, 13C 39.43 ppm) and H3PO4
85%, respectively). The assignments of the 1H and 13C resonances
were made based on 2D NMR experiments (HSQC and HMBC).
The NMR spectra were processed using the MestReC and MestReN-
ova software [51].
7.1 Hz), 2.43 (s, 3H, C6H4CH3), 4.06 (ABXY3 spin system with dA
3
2
3
4.00 and dB 4.11 ppm, JHH 7.1, JHH 10.0, JPH 7.6 and 7.4 Hz, 4H
3
CH3CH2), 7.29 (d, 2H, C6H4-meta, JHH 8.1 Hz), 7.84 (d, 2H, C6H4-
3
ortho, JHH 8.2 Hz). The resonance for the NH proton was not ob-
served. 13C NMR (CDCl3): d 15.81 (d, CH2CH3, JPC 7.6 Hz), 21.58
3
2
(s, C6H4CH3), 64.33 (d, CH2CH3, JPC 5.5 Hz), 127.14 (s, C6H4-ortho),
129.38 (s, C6H4-meta), 138.28 (s, C6H4-ipso), 143.90 (s, C6H4-para).
31P NMR: d ꢁ5.28s. FT-IR (cmꢁ1):
m
(NH) 2732vs, (P@O) 1240s,
m
m
as(SO2) 1244s,
as[PN(H)S] 928s.
m
as(PNS) 1162s,
m
s(SO2) 1025s, m(POC) 972s,
m
[{SP(OEt)2}(O2SC6H4Cl-4)]NH (4), from n-BuLi in n-hexane
(13.23 mL 1.6 M, 21.20 mmol), (EtO)2P(S)NH2 (3.583 g,
21.20 mmol) and 4-ClC6H4SO2Cl (2.237 g, 10.60 mmol). Yield:
3.10 g (85.2%). M.p. 142 °C (Lit. [43] 141–2 °C). Anal. Calc. for C10-
H15ClNO4PS2 (MW 343.78): C, 34.94; H, 4.40; N, 4.07. Found: C,
34.83; H, 4.34; N, 4.15%. 1H NMR (CDCl3): d 1.27 (t, 6H, CH3CH2,
3JHH 7.7 Hz), 4.09 (ABXY3 spin system with dA 4.03 and dB
3
2
3
4.14 ppm, JHH 7.1, JHH 9.8, JPH 9.3 and 9.2 Hz, 4H CH3CH2), 6.81
3
2.2. Syntheses
(s, br., 1H, NH) 7.51 (d, 2H, C6H4-meta, JHH 8.7 Hz), 7.92 (d, 2H,
C6H4-ortho, JHH 8.7 Hz). 13C NMR (CDCl3): d 15.63 (d, CH2CH3,
3
2
2.2.1. Preparation of [{OP(OEt)2}(O2SMe)]NH (1)
3JPC 8.65 Hz), 64.79 (d, CH2CH3, JPC 5.0 Hz), 129.07 (s, C6H4-ortho),
A solution of n-BuLi in n-hexane (8.76 mL 1.6 M, 14.02 mmol)
was added dropwise at room temperature to a stirred solution of
(EtO)2P(O)NH2 (2.145 g, 14.02 mmol) in 50 mL of anhydrous tetra-
hydrofurane, under argon atmosphere. The reaction mixture was
stirred for 3 h at room temperature. Then a solution of MeSO2Cl
(0.802 g, 0.542 mL, 7.01 mmol) in 50 mL of anhydrous THF was
added dropwise. After 12 h of stirring the solvent was removed
in vacuum. To the remained solid toluene (30 mL) was added and
the obtained suspension was treated with water (100 mL). From
129.19 (s, C6H4-meta), 138.98 (s, C6H4-ipso), 140.04 (s, C6H4-para).
31P NMR: d 57.26s. FT-IR (cmꢁ1):
m
(NH) 2987vs,
m
as(SO2) 1246,
(P@S)
mas(PNS) 1168vs,
m
s(SO2) 1011s, 1083vs, as[PN(H)S] 886s, m
m
619vs.
2.2.2. Preparation of K[{OP(OEt)2}(O2SMe)N] (5)
A
reaction mixture of [{OP(OEt)2}(O2SMe)]NH (0.300 g,
1.30 mmol) and KOBut (0.146 g, 1.30 mmol) in 30 mL of anhydrous
diethyl ether was stirred at room temperature for 24 h. The

D. Oltean et al. / Polyhedron 53 (2013) 67–75
69
resulting solid was separated by filtration and then dried under
231 (100) [{OP(OEt)2}(O2SMe)N+H]+ FT-IR (cmꢁ1):
as(PNS) 1154s, (PO) 1075s, s(SO2) 1024s, m(POC) 982vs.
m
as(SO2) 1243s,
vacuum. The title compound was obtained quantitatively as a col-
orless powder. M.p. 69 °C (dec.). Anal. Calc. for C5H13NO5PSK (MW
269.29): C, 22.30; H, 4.87; N, 5.20. Found: C, 22.17; H, 4.95; N,
m
m
m
2.2.4. Preparation of Pd[{OP(OEt)2}(O2SPh)N]2 (10)
reaction mixture of PdCl2 (0.05 g, 0.28 mmol) and
3
5.32%. 1H NMR (CDCl3): d 1.28 (t, 6H, CH3CH2, JHH 7.00 Hz), 2.99
A
3
3
(s, 3H, CH3S), 3.98 (dq, 4H, CH3CH2, JHH 7.02, JPH 6.89 Hz). 13C
K[{OP(OEt)2}(O2SPh)N] (0.185 g, 0.56 mmol) in 25 mL of anhy-
drous dichloromethane was stirred at room temperature for 24 h.
The orange clear solution was separated by filtration and the sol-
vent was removed in vacuum. The title compound resulted as an
orange oily product. Yield: 0.112 g (57.8%). Anal. Calc. for C20H30N2-
O10P2S2Pd (MW 690.95): C, 34.77; H, 4.38; N, 4.05. Found: C, 34.92;
3
NMR (CDCl3): d 16.18 (d, OCH2CH3, JPC 7.6 Hz), 43.04 (s, SCH3),
61.94 (d, OCH2CH3, JPC 6.3 Hz), 31P NMR: d ꢁ1.48s. APCI+ MS (m/
2
z, %): 577 (41) [2M+K]+, 308 (100) [M+K]+, 270 (89) [M+H]+. FT-IR
(cmꢁ1):
1022s,
Compounds 6–8 were prepared similarly.
m
(PO) 1089s,
mas(SO2) 1245vs, mas(PNS) 1165vs, ms(SO2)
m
(POC) 988s.
H, 4.51; N, 3.97%. 1H NMR (CDCl3): d 1.04 (t, 6H, CH3CH2, JHH
3
3
3
K[{OP(OEt)2}(O2SPh)N] (6), from [{OP(OEt)2}(O2SPh)]NH (0.90 g,
3.07 mmol) and KOBut (0.344 g, 3.07 mmol). M.p. 178 °C. Anal.
Calc. for C10H15NO5PSK (MW 331.36): C, 36.25; H, 4.56; N, 4.23.
Found: C, 36.48; H, 4.73; N, 4.51%. 1H NMR (DMSO-d6): d 1.06 (t,
6.82 Hz), 3.84 (dq, 4H, CH3CH2, JHH 6.7, JPH 13.5 Hz), 7.35 (m,
3
3H, C6H5-meta + para), 7.93 (d, 2H, C6H5-ortho, JHH 7.3 Hz). 13C
3
NMR (CDCl3): d 15.79 (d, CH2CH3, JPC 7.8 Hz), 62.94 (d, CH2CH3,
2JPC 5.75 Hz), 126.56 (s, C6H5-ortho), 128.37 (s, C6H5-meta),
131.43 (s, C6H5-para), 143.76 (s, C6H5-ipso). 31P NMR (CDCl3): d
ꢁ3.93s. APCI+ MS (m/z, %): 692 (12) [M+H]+, 294 (100)
3
3
3
6H, CH3CH2, JHH 7.04 Hz), 3.72 (dq, 4H, CH3CH2, JHH 7.1, JPH
7.1 Hz), 7.39 (m, 3H, C6H5-meta + para), 7.77 (m, 2H, C6H5-ortho).
13C NMR (DMSO-d6): d 16.53 (d, CH2CH3, 3JPC 7.5 Hz), 60.76 (d, CH2-
[{OP(OEt)2}(O2SPh)NH]+. FT-IR (cmꢁ1):
1174vs, m(PO) 1064s, ms(SO2) 1037s, m
m
as(SO2) 1244s,
(POC) 995s.
Compounds 11–13 were prepared similarly.
Pd[{OP(OEt)2}(O2SC6H4CH3-4)N]2 (11), from PdCl2 (0.054 g,
0.305 mmol) and K[{OP(OEt)2}(O2SC6H4CH3-4)N] (0.211 g,
mas(PNS)
2
CH3, JPC 6.0 Hz), 125.97 (C6H5-ortho), 128.21 (C6H5-meta), 129.85
(C6H5-para), 148.60 (C6H5-ipso). 31P NMR (DMSO-d6): d ꢁ3.17s.
APCI+ MS (m/z, %): 332 (100) [M+H]+, 316 (47) [MꢁO+H]+, 294
(68) [MꢁK+H]+. FT-IR (cmꢁ1):
m
(PO) 1065s,
mas(SO2) 1243vs,
m
as(PNS) 1188vs,
m
s(SO2) 1022s,
m
(POC) 1001s.
0.61 mmol). The title compound resulted as an orange solid. Yield:
0.191 g (87%). M.p. 75 °C. Anal. Calc. for C22H34N2O10P2S2Pd (MW
719.01): C, 36.75; H, 4.77; N, 3.90. Found: C, 36.89; H, 4.96; N,
K[{OP(OEt)2}(O2SC6H4CH3-4)N] (7), from [{OP(OEt)2}(O2SC6H4-
CH3-4)]NH (1.208 g, 3.93 mmol) and KOBut (0.440 g, 3.93 mmol).
3
M.p. 111 °C. Anal. Calc. for C11H17NO5PSK (MW 345.39): C, 38.25;
3.73%. 1H NMR (CDCl3): d 1.13 (t, 6H, CH3CH2, JHH 6.91 Hz), 2.37
H, 4.96; N, 4.06. Found: C, 38.51; H, 4.72; N, 4.11%. 1H NMR
(s, 3H, C6H4CH3), 3.90 (dq, 4H CH3CH2, JHH 6.8, JPH 13.6 Hz),
3
3
3
3
3
(CDCl3):
d
1.03 (t, 6H, CH3CH2, JHH 7.02 Hz), 2.33 (s, 3H,
7.16 (d, 2H, C6H4-meta, JHH 8.1 Hz), 7.82 (d, 2H, C6H4-ortho, JHH
3
3
3
C6H4CH3), 3.75 (dq, 4H CH3CH2, JHH 7.00, JPH 7.00 Hz), 7.06 (d,
8.1 Hz). 13C NMR (CDCl3): d 15.84 (d, CH2CH3, JPC 7.6 Hz), 21.44
3
3
2H, C6H4-meta, JHH 8.1 Hz), 7.78 (d, 2H, C6H4-ortho, JHH 8.1 Hz).
(s, C6H4CH3), 63.07 (d, CH2CH3, 2JPC 5.45 Hz), 126.63 (s, C6H4-meta),
129.01 (s, C6H4-ortho), 140.78 (s, C6H4-ipso), 142.02 (s, C6H4-para).
31P NMR(CDCl3): d ꢁ3.85s. ESI+ MS (m/z, %): 720 (18) [M+H]+, 308
13C NMR (CDCl3): d 15.88 (d, CH2CH3, JPC 7.8 Hz), 21.32 (s,
3
2
C6H4CH3), 62.01 (d, CH2CH3, JPC 6.02 Hz), 126.03 (s, C6H4-meta),
128.75 (s, C6H4-ortho), 140.45 (s, C6H4-para), 142.98 (s, C6H4-ipso).
(100) [{OP(OEt)2}(O2SC6H4CH3-4)N+H]+. FT-IR (cmꢁ1):
m
as(SO2)
(POC) 990vs.
Pd[{SP(OEt)2}(O2SC6H4Cl-4)N]2 (12), from PdCl2 (0.054 g,
0.305 mmol) and K[{SP(OEt)2}(O2SC6H4Cl-4)N] (0.235 g,
31P NMR (CDCl3): d ꢁ2.31s. ESI+ MS (m/z, %): 729 (100) [2M+K]+,
1253s, mas(PNS) 1172vs, ms(SO2) 1033vs, m(PO) 1075s, m
385 (32) [M+K]+. FT-IR (cmꢁ1):
m
(PO) 1072s,
mas(SO2) 1252vs, mas(-
PNS) 1173vs, ms(SO2) 1033s, m(POC) 988s.
K[{SP(OEt)2}(O2SC6H4Cl-4)N] (8), from [{SP(OEt)2}(O2SC6H4Cl-
4)]NH (2.00 g, 5.82 mmol) and KOBut (0.652 g, 5.82 mmol). M.p.
164 °C. Anal. Calc. for C10H14ClNO4PS2K (MW 381.87): C, 31.45;
H, 3.70; N, 3.67. Found: C, 31.38; H, 3.78; N, 3.66%. 1H NMR
0.61 mmol). Yield: 0.227 g (94%). M.p. 195–6 °C. Anal. Calc. for C20-
H28N2O8Cl2P2S4Pd (MW 791.96): C, 30.33; H, 3.56; N, 3.54. Found.
C, 30.12; H, 3.48; N, 3.61%. 1H NMR (CDCl3): d 1.36 (t, 6H, CH3CH2,
3JHH 6.8 Hz), 4.21 (ABXY3 spin system with dA 4.14 and dB 4.27 ppm,
3JHH 7.0, 2JHH 9.6, 3JPH 8.2 and 8.4 Hz, 4H CH3CH2), 7.45 (d, 2H, C6H4-
3
(DMSO-d6): d 1.09 (t, 6H, CH3CH2, JHH 7.04 Hz), 3.79 (dq, 4H, CH3-
CH2, 3JHH 7.5, 3JPH 7.5 Hz), 7.43 (d, 2H, C6H4-meta, 3JHH 8.3 Hz), 7.75
meta, JHH 7.9 Hz), 7.88 (d, 2H, C6H4-ortho, JHH 7.9 Hz). 13C NMR
3
3
3
3
2
(d, 2H, C6H4-ortho, JHH 8.3 Hz). 13C NMR (DMSO-d6): d 16.33 (d,
(CDCl3): d 15.69 (d, CH2CH3, JPC 8.0 Hz), 66.56 (d, CH2CH3, JPC
6.0 Hz), 128.62 (s, C6H4-meta), 128.85 (s, C6H4-ortho), 138.76 (s,
C6H4-ipso), 140.81 (s, C6H4-para). 31P NMR (CDCl3): d 57.77s. APCI+
MS (m/z, %): 1242 (18) [Pd2[{SP(OEt)2}(O2SC6H4Cl-4)N]3]+, 793
3
2
CH2CH3, JPC 8.5 Hz), 60.98 (d, CH2CH3, JPC 5.92 Hz), 127.98 (s,
C6H5-meta), 128.48 (s, C6H5-ortho), 134.29 (s, C6H5-para), 147.16
(s, C6H5-ipso). 31P NMR (DMSO-d6): d 54.75s. APCI+ MS (m/z, %):
383 (100) [M+H]+, 343 (58) [MꢁK+H]+. FT-IR (cmꢁ1):
m
as(SO2)
(PS)
(100) [M+H]+, 764 (20) [MꢁEt]+. FT-IR (cmꢁ1):
m
as(SO2) 1277s,
1233s,
633vs.
m
as(PNS) 1158s, 1187s,
m
s(SO2) 1043vs,
m
(POC) 979vs,
m
mas(PNS) 1161vs, ms(SO2) 1059s, 1090vs, m(POC) 987vs, m(PS) 611vs.
Pd[(SPPh2)(O2SPh)N]2 (13), from PdCl2 (0.054 g, 0.305 mmol)
and K[(SPPh2)(O2SPh)N] (0.251 g, 0.61 mmol). Yield: 0.148 g
(57%). M.p. 230 °C (dec.). Anal. Calc. for C36H30N2O4P2S4Pd (MW
851.25): C, 50.80; H, 3.55; N, 3.29. Found: C, 50.57; H, 3.51; N,
3.42%. 1H NMR (DMSO-d6): d 7.31 (m, 9H, PC6H5-meta + para + SC6-
H5-meta + para), 7.84 (m, 6H, PC6H5-ortho + SC6H5-ortho). 13C NMR
(DMSO-d6): d 126.37 (s, SC6H5-ortho), 127.65 (s, SC6H5-meta),
2.2.3. Preparation of Pd[{OP(OEt)2}(O2SMe)N]2 (9)
reaction mixture of PdCl2 (0.050 g, 0.28 mmol) and
A
K[{OP(OEt)2}(O2SMe)N] (0.151 g, 0.56 mmol) in 25 mL of anhy-
drous methanol was stirred at room temperature for 24 h, when
an abundant yellow precipitate formed. The yellow-orange clear
solution was separated by filtration and the solvent was removed
in vacuum. The title compound resulted as a yellow solid product
with a very low solubility in methanol and chloroform. Yield:
0.121 g (76.1%). M.p. 202 °C. Anal. Calc. for C10H26N2O10P2S2Pd
(MW 566.81): C, 21.19; H, 4.62; N, 4.94. Found: C, 21.33; H, 4.57;
3
127.86 (d, PC6H5-meta, JPC 6.4 Hz), 129.49 (s, SC6H5-para), 129.67
4
2
(d, PC6H5-para, JPC 2.7 Hz), 131.12 (d, PC6H5-ortho, JPC 10.6 Hz),
141.91 (d, PC6H5-ipso, JPC 105.5 Hz), 149.1 (s, SC6H5-ipso). 31P
1
NMR (DMSO-d6): d 36.58s. 1H NMR (CDCl3, 50 °C): d 7.12 (m, 3H,
SC6H5-meta + para), 7.59 (m, 8H, PC6H5-meta + para + SC6H5-ortho),
N, 4.97%. 1H NMR (DMSO-d6): d 1.14 (t, 6H, CH3CH2, JHH 7.1 Hz),
7.97 (dd, PC6H5-ortho, JHH 7.7, JPH 14.3 Hz). 13C NMR (CDCl3,
3
3
3
3
3
2.67s (3H, CH3), 3.84 (dq, 4H, CH3CH2, JHH 7.1, JPH 7.1 Hz). 13C
50 °C): d 126.75 (s, SC6H5-ortho), 127.88 (s, SC6H5-para), 127.97
3
3
NMR (DMSO-d6): d 16.67 (d, CH2CH3, JPC 7.5 Hz), 43.54 (s, CH3),
(s, SC6H5-ortho), 128.41 (d, PC6H5-meta, JPC 13.6 Hz), 131.19 (d,
4
2
60.69 (d, CH2CH3, 2JPC 6.0 Hz). 31P NMR (DMSO-d6): d ꢁ1.93s. APCI+
MS (m/z, %): 568 (27) [M+H]+, 337 (72) [Pd{OP(OEt)2}(O2SMe)N]+,
PC6H5-para, JPC 5.4 Hz), 132.58 (d, PC6H5-ortho, JPC 12.6 Hz), Res-
onances for ipso-carbons were not observed. 31P NMR (CDCl3,

70
D. Oltean et al. / Polyhedron 53 (2013) 67–75
Table 1
Crystal data and structure refinement for [{OP(OEt)2}(O2SR)]NH [R = Me (1), Ph (2)], [{SP(OEt)2}(O2SC6H4Cl-4)]NH (4) and Pd[{SP(OEt)2}(O2SC6H4Cl-4)N]2 (12).
1
2
4
12
Empirical formula
Formula weight
Temperature (K)
Wavelength (Å)
Crystal system
Space group
a (Å)
C5H14NO5PS
231.20
297(2)
0.71073
orthorhombic
Pbca
C10H16NO5PS
293.27
297(2)
C10H15ClNO4PS2
343.77
297(2)
C20H28Cl2N2O8P2PdS4
791.92
297(2)
0.71073
triclinic
0.71073
0.71073
triclinic
triclinic
ꢀ
ꢀ
ꢀ
P1
P1
P1
8.589(3)
9.657(4)
26.455(10)
90.00
90.00
90.00
2194.4(15)
8
1.400
0.434
976
8.4766(8)
11.7849(11)
15.6223(14)
70.733(2)
75.275(2)
79.802(2)
1417.4(2)
4
8.2269(9)
9.3827(10)
11.5421(15)
87.486(2)
69.166(2)
70.978(2)
784.59(16)
2
8.5715(9)
9.7030(10)
11.0492(12)
100.957(2)
104.597(2)
111.793(2)
783.52(14)
1
b (Å)
c (Å)
a
(°)
b (°)
c
(°)
Volume (Å3)
Z
Dcalc (g/cm3)
1.374
0.353
616
1.455
0.618
356
1.678
1.176
400
Absorption coefficient (mmꢁ1
F(000)
)
Crystal size (mm)
h Range for data collections (°)
Reflections collected
0.30 ꢂ 0.26 ꢂ 0.23
1.54–25.02
14589
0.32 ꢂ 0.27 ꢂ 0.26
1.41–25.00
13749
0.47 ꢂ 0.46 ꢂ 0.26
1.89–25.00
7575
0.25 ꢂ 0.23 ꢂ 0.19
2.01–25.00
7590
Independent reflections [R(int)]
Maximum and minimum transmissions
Refinement method
1939 [R(int) = 0.1288]
0.9068 and 0.8808
4978 [R(int) = 0.0526]
0.9139 and 0.8956
2764 [R(int) = 0.0324]
0.8558 and 0.7598
2756 [R(int) = 0.0328]
0.8075 and 0.7576
Full-matrix least-squares on F2
Data/restraints/parameters
1939/1/125
1.308
4978/2/337
1.084
2764/1/178
1.111
2756/0/200
1.106
Goodness-of-fit on F2
Final R indicies [I > 2
R indices (all data)
r
(I)]
R1 = 0.1206, wR2 = 0.2062
R1 = 0.1522, wR2 = 0.2183
0.342 and ꢁ0.404
R1 = 0.0812, wR2 = 0.1821
R1 = 0.1122, wR2 = 0.1990
0.451 and ꢁ0.548
R1 = 0.0482, wR2 = 0.1162
R1 = 0.0551, wR2 = 0.1198
0.231 and ꢁ0.303
R1 = 0.0375, wR2 = 0.0888
R1 = 0.0425, wR2 = 0.0913
0.508 and ꢁ0.313
Largest difference in peak and hole (e Åꢁ3
)
50 °C): d 84.15s. APCI+ MS (m/z, %): 851 (32) [M]+, 819 (24)
occupancy of 39:61, respectively. The software package SHELX-97
was used for structure solving and refinement [52]. The drawings
were created with the DIAMOND program [53].
[Mꢁ32]+, 478 (100) [Pd{(SPPh2)(O2SPh)N}]+. FT-IR (cmꢁ1):
mas(SO2)
1258m, mas(PNS) 1149vs, ms(SO2) 1046vs, m(PS) 591vs.
2.3. Crystal structure determination of compounds 1, 2, 4 and 12
3. Results and discussion
Colorless crystals of compounds 1, 2 and 4, as well as orange
crystals of compound 12ꢀwere grown by slow diffusion from a mix-
ture of CH2Cl2/n-hexane (1/5, v/v). The crystals were attached with
paraton/N oil to a cryoloop. Data collection and processing was car-
ried on a Bruker SMART APEX CCDC system, using graphite-mono-
3.1. Preparation and spectroscopic characterization
Several organophosphorus acids of type [{XP(OEt)2}(O2SR)]NH
[X = O; R = Me (1), Ph (2), C6H4CH3-4 (3); X = S, R = C6H4Cl-4 (4)]
were obtained using a similar procedure as we reported before
for the ligands of type [(SPPh2)(O2SR)]NH (R = Me, Ph, C6H4CH3-
4) [40]. They were deprotonated with KOBut in order to obtain
the potassium salts 5–8 (Scheme 2).
Palladium(II) complexes were synthesized by salt metathesis
reactions between the potassium salts of the appropriate organo-
phosphorus acids and palladium dichloride, in a 2:1 molar ratio
(Scheme 2). In order to see how the coordination behavior of the
ligand might be influenced either by the chalcogen or the organic
groups attached to phosphorus and sulfur, respectively, we
chromated Mo K
a radiation (k = 0.71073 Å). Details of the crystal
structure determination and refinement for compounds 1, 2, 4
and 11ꢀare given in Table 1.
The structures were refined with anisotropic thermal parame-
ters. The hydrogen atoms were refined with a riding model and a
mutual isotropic thermal parameter. The hydrogen atoms attached
to nitrogen were found in the electronic density map and were re-
fined to a restrained distance of 0.88(2) Å in 1, 0.850(18) Å in 2a,
0.839(19) Å in 2b and 0.847(17) Å in 4, respectively. One CH2CH3
group in compound 12 is disordered over two positions, with a site
Scheme 2.

D. Oltean et al. / Polyhedron 53 (2013) 67–75
71
prepared also the complex Pd[(SPPh2)(O2SPh)N]2 (13), using a sim-
ilar procedure.
The compounds described in this paper, excepting complex 10
which was isolated as an orange oil, were obtained as microcrystal-
line solids, colorless the free acids and their potassium salts, and
yellow (9) or orange (11–13) the palladium(II) complexes. All spe-
cies were investigated by multinuclear NMR (1H, 13C, 31P) and IR
spectroscopy. The potassium salts and the palladium(II) complexes
were characterized also by mass spectrometry. It is noteworthy to
observe that the potassium salts of the discussed species are solu-
ble in CDCl3, while the palladium complexes 9 and 13 have a very
poor solubility in CDCl3 or methanol-d6, but they are soluble in
DMSO.
For all species the NMR spectra are in accordance with the ex-
pected resonances for the organic groups attached to phosphorus
and sulfur, respectively.
Fig. 2. ORTEP plot of [{OP(OEt)2}(O2SPh)]NH (2). The atoms are drawn with 30%
probability ellipsoids.
The ethoxy groups attached to phosphorus show in the aliphatic
region 1H resonances with a multiplet pattern due to the proton–
proton and phosphorus–proton couplings, respectively. In all cases
the resonance determined by the CH3 protons appears as a triplet,
while the resonances determined by the CH2 protons have a more
or less complicate pattern. For the CHAHBCH3 protons in the ethoxy
groups, the combined proton (CH3)–proton (CHA), proton (CH3)–
proton (CHB), proton (CHA) –proton (CHB) and phosphorus–proton
couplings give rise to a complex ABXY3 system. As a consequence,
the complex multiplet resonances centered at d 4.06 ppm in 3 and
4.09 ppm in 4, respectively, are determined by the non-equivalent
3
3
diastereotopic methylene protons and different JHH,
2JHH and JPH
coupling constants. The CH2 resonances in case of the free acid 2
and the palladium complex 12 have the appearance of a ‘‘doublet
of sextets’’ centered at 4.03 ppm in 2 and 4.21 ppm in 12, respec-
tively. They correspond also to AB systems, further split by cou-
plings with phosphorus and the CH3 protons, but with very close
Fig. 3. ORTEP plot of [{SP(OEt)2}(O2SC6H4Cl-4)]NH (4). The atoms are drawn with
30% probability ellipsoids.
2
3JPH and JHH coupling constants. To better understand this behav-
ior and to find the appropriate values for the corresponding cou-
pling constants we simulated the resonances given by the CH2
protons in compounds 2–4 and 12, respectively. A theoretical
interpretation together with the experimental and simulated spec-
tra for these compounds are given in ESI (Figs. S1–S4 and Table S1).
In case of the free acid 1, as well as in case of the potassium salts
5–8 and the palladium complex 9, the 1H NMR resonances deter-
mined by the methylene protons have the appearance of a quintet,
due to the equal values of the 3JHH and 3JPH coupling constants. The
non-equivalence of the CH2 protons is no more observable in the
spectra at the NMR time scale for these species.
The 13C NMR spectra exhibit doublet resonances for the CH2 and
CH3 carbons in the ethoxy groups, due to the phosphorus–carbon
couplings and singlet resonances for the carbons in the organic
groups attached to sulfur.
The 31P NMR spectra exhibit only one resonance in all cases,
corresponding to the phosphorus atom in the (EtO)2P(X) (X = O,
S) moiety, slightly downfield shifted in case of the metal containing
species in comparison with the free acids. In case of the palladium
complexes, the presence of only one 31P NMR resonance suggests
the same coordination of the two ligand units to palladium in
solution.
The CH2 protons in the palladium complexes 10 and 11 give rise
to resonances with appearance of a ‘‘sextet’’, in fact a doublet of
An interesting behavior was observed in case of compound 13.
It has a very poor solubility in common organic solvents, but it has
a good solubility in DMSO at room temperature. The solubility in
CDCl3 increases with increasing the temperature. The 31P chemical
shifts in CDCl3 (84.15 ppm) and DMSO-d6 (36.58 ppm) suggest a
different coordination behavior of the ligand in these solvents, i.e.
a S,N-bidentate coordination in CDCl3 and a S,O-coordination in
DMSO-d6. This observation is in accordance with the situation de-
scribed before for the palladium(II) complexes Pd[Ph2-
P(S)NP(O)(OPh)2]2 and Pd[Ph2P(S)NP(S)(OPh)2]2, for which
monomeric structures with four membered SPNPd and six mem-
bered SPNPSPd chelate rings, respectively, were found in solid state
and the 31P chemical shift in solution for the R2P(S) moiety in these
species was found at d 87.3 ppm in first case and at 46.8 ppm in the
second one [37].
3
3
quartets determined by the different JHH and JPH coupling con-
stants (6.7 and 13.5 Hz in 10 and 6.8 and 13.6 Hz in 11,
respectively).
The mass spectra (ESI+ or APCI+) present the molecular or the
pseudo-molecular ion for all the investigated species. In case of
complex 12, the peak at m/z = 1242, corresponding to the species
[Pd2[{SP(OEt)2}(O2SC6H4Cl-4)N]3]+, suggests the association of the
monomeric units. The mass spectra of the potassium salts contain
Fig. 1. ORTEP plot of [{OP(OEt)2}(O2SMe)]NH (1). The atoms are drawn with 30%
probability ellipsoids.

72
D. Oltean et al. / Polyhedron 53 (2013) 67–75
Table 2
Important interatomic distances (Å), bond angles (°) and torsion angles (°) for compounds 1, 2 and 4.
1
2a
2b
4
S(1)–O(1)
S(1)–O(2)
S(1)–N(1)
S(1)–C(1)
P(1)–O(3)
P(1)–O(5)
P(1)–O(4)
P(1)–N(1)
N(1)–H(1N)
H(1N)ꢀ ꢀ ꢀO(30)a
H(1N)–N(1)–S(1)
H(1N)–N(1)–P(1)
S(1)–N(1)–P(1)
C(1)–S(1)–N(1)–P(1)
O(3)–P(1)–N(1)–S(1)
1.433(5)
1.435(5)
1.660(6)
1.735(8)
1.466(5)
1.568(5)
1.557(6)
1.640(6)
0.88(2)
1.94
105(5)
125(5)
126.7(4)
69.95
ꢁ13.78
S(1)–O(1)
S(1)–O(2)
S(1)–N(1)
S(1)–C(1)
P(1)–O(3)
P(1)–O(4)
P(1)–O(5)
P(1)–N(1)
N(1)–H(1N)
H(1N)ꢀ ꢀ ꢀO(8)
H(1N)–N(1)–S(1)
H(1N)–N(1)–P(1)
S(1)–N(1)–P(1)
C(1)–S(1)–N(1)–P(1)
O(3)–P(1)–N(1)–S(1)
1.430(3)
1.421(4)
1.636(4)
1.756(5)
1.459(4)
1.541(4)
1.536(4)
1.650(4)
0.850(18)
1.93
S(2)–O(6)
S(1)–O(7)
S(2)–N(2)
S(2)–C(11)
P(2)–O(8)
P(2)–O(9)
P(2)–O(10)
P(2)–N(2)
1.417(4)
1.423(3)
1.636(4)
1.756(5)
1.453(3)
1.548(4)
1.553(4)
1.638(4)
0.839(19)
1.88
S(1)–O(1)
S(1)–O(2)
S(1)–N(1)
S(1)–C(1)
P(1)–S(2)
P(1)–O(3)
P(1)–O(4)
P(1)–N(1)
N(1)–H(1N)
1.435(2)
1.422(2)
1.637(3)
1.757(3)
1.9138(11)
1.564(2)
1.561(2)
1.683(3)
0.847(17)
N(2)–H(2N)
H(2N)ꢀ ꢀ ꢀO(3)
H(2N)–N(2)–S(2)
H(2N)–N(2)–P(2)
S(2)–N(2)–P(2)
C(11)–S(2)–N(2)–P(2)
O(8)–P(2)–N(2)–S(2)
112.0(3)
117.0(3)
129.5(3)
77.24
110.0(3)
119.0(3)
129.9(3)
90.41
H(11)–N(1)–S(1)
H(11)–N(1)–P(1)
S(1)–N(1)–P(1)
C(1)–S(1)–N(1)–P(1)
S(2)–P(1)–N(1)–S(1)
113.0(2)
118.0(2)
127.62(14)
81.40
ꢁ176.19
ꢁ172.11
ꢁ173.06
a
Symmetry equivalent position given by ‘‘prime’’ 0.5 ꢁ x, ꢁ0.5 + y, z.
signals at m/z values higher than the expected molecular mass,
thus suggesting possible polymeric associations also.
The IR spectra were recorded in order to confirm the deprotona-
tion in case of the potassium salts and the palladium complexes.
Strong absorptions around 900 cmꢁ1 in all acids, as well as med-
ium absorptions around 2700 cmꢁ1 in case of acids 1–3 and at
2987 cmꢁ1 in case of acid 4, respectively, were assigned to
m(NH)
vibrations. In the spectra of the potassium salts and the palladium
complexes these bands are no more present, indicating that the li-
gands are deprotonated. The stretching frequency assigned to
m
(NH) in acid 4 is higher (2987 cmꢁ1) than in the other acids
(around 2700 cmꢁ1) probably as a consequence of the monomeric
solid-state structure of this compound, in comparison with com-
pounds 1 and 2, where the NH proton is involved in intermolecular
interactions, as was observed by single-crystal X-ray diffraction
(see subsequent discussion) and as it was previously noted for sev-
eral imidodiphosphinic acids [37]. Strong and very strong bands
were assigned to
m ms(SO2) (1060–
as(SO2) (1280–1200 cmꢁ1),
1020 cmꢁ1) and as(PNS) (1180–1150 cmꢁ1) stretching vibrations.
m
Fig. 4. Dimeric association through NHꢀ ꢀ ꢀOP bonding in [{OP(OEt)2}(O2SPh)]NH (2).
Hydrogen atoms, excepting those involved in intermolecular interactions, are
omitted for clarity.
Characteristic bands in the regions 1230–1240 cmꢁ1 are consistent
with P@O bonds in acids 1–3, while in case of the metal containing
species the m(PO) frequencies are lowered. This behavior is deter-
mined by a decreasing of the bond strengths due to the interaction
with the metal center. For the compounds containing PS moieties
characteristic bands were observed around 600 cmꢁ1 [42,54–56].
3.2. Crystal and molecular structure of 1, 2 and 4
The ORTEP-like diagrams with the corresponding numbering
scheme for the free organophosphorus acids 1, 2 and 4 are depicted
in Figs. 1–3, respectively, while relevant bond distances and angles
are given in Table 2.
The monomeric units are similar in all three species, with the
remark that compound 2 contains two independent molecules in
the unit cell.
In all three species the acidic proton is attached to nitrogen. The
phosphorus–chalcogen interatomic distances have typical values
Fig. 5. Polymeric chain in [{OP(OEt)2}(O2SMe)]NH (1). Hydrogen atoms, excepting
those involved in intermolecular interactions, are omitted for clarity.
for P@O and P@S double bonds, cf. P@O 1.486(6), P–O 1.526(6) Å
in Ph2P(@O)OH [57] and P@S 1.954(1), P–S 2.071(1) Å in Ph2-
P(@S)–N@P(–SMe)Ph2 [58], while the phosphorus–nitrogen inter-
atomic distances correspond to single P–N bonds cf. P@N
1.562(2) and P–N 1.610(2) Å in Ph2P(@S)–N@P(–SMe)Ph2 [58].
The nitrogen–sulfur distances are of similar magnitude with those
found in the related species (SPPh2)(O2SMe)NH [1.634(2) Å], and
(SPPh2)(O2SC6H4CH3-4)NH [1.641(1) Å] [40].
Scheme 3.

D. Oltean et al. / Polyhedron 53 (2013) 67–75
73
Fig. 6. ORTEP plot of Pd[{SP(OEt)2}(O2SC6H4Cl-4)N]2 (12). The atoms are drawn with 30% probability ellipsoids. Hydrogen atoms are omitted for clarity.
P(2)N(2)S(2), respectively, while in 4 C(1) and O(3) are deviated
at 1.668 and 0.219 Å, respectively, from the P(1)N(1)S(1) plane].
In compounds 1 and 2 the molecules are associated by N–Hꢀ ꢀ ꢀ
O@P hydrogen bonding, {N(1)H(1N)ꢀ ꢀ ꢀO(30) 1.94 Å, N(1)–H(1N)ꢀ ꢀ ꢀ
O(30) 167.01° in 1, N(1)H(1N)ꢀ ꢀ ꢀO(8) 1.93(4) Å, N(1)–H(1N)ꢀ ꢀ ꢀO(8)
171.4(3)°, N(2)H(2N)ꢀ ꢀ ꢀO(3) 1.88(5) Å, N(2)–H(2)ꢀ ꢀ ꢀO(3) 172.6(4)°
Table 3
Important interatomic distances (Å) and angles (°) for compound 12.
Pd(1)–N(1)
S(1)–O(1)
S(1)–O(2)
S(1)–N(1)
2.038(3)
1.423(3)
1.430(3)
1.625(3)
1.771(4)
2.857(3)
180.00
180.00
77.82(9)
102.18(9)
Pd(1)–S(2)
P(1)–O(3)
P(1)–O(4)
P(1)–S(2)
P(1)–N(1)
2.3445(10)
1.547(3)
1.547(3)
1.9916(15)
1.613(3)
in 2, cf.
RrvdW(HO) 2.60 Å [59]}, of a similar magnitude as in
S(1)–C(1)
Cl(10)ꢀ ꢀ ꢀH(9A2)a
N(1)–Pd(1)–N(1a)
S(2)–Pd(1)–S(2a)
N(1)–Pd(1)–S(2)
N(1a)–Pd(1)–S(2)
(SPPh2){OP(OEt)2}NH [NHꢀ ꢀ ꢀOP 1.79 Å] [60]. While in compound
2 this type of association results in centrosymmetric dimeric units
of molecules 2a and 2b (Fig. 4), in case of compound 1 a polymeric
chain is formed (Fig. 5). A dimeric structure determined by
hydrogen bonding was previously found in (SPPh2)(O2SC6H4Me-
4)NH, but in this case dimmers are formed by intermolecular
hydrogen bonding involving one oxygen atom of the RSO2 moiety
and the acidic proton NH [NHꢀ ꢀ ꢀOS 2.03(2) Å] [40]. In case of acid
1, the polymeric chains are further associated in a 3D layered
structure by weak hydrogen contacts involving one oxygen and
one hydrogen of the MeSO2 moiety in a neighboring molecule,
[O(2)ꢀ ꢀ ꢀH(1A00) 2.41 Å, Fig. S5].
P(1)–N(1)–S(1)
P(1)–N(1)–Pd(1)
S(1)–N(1)–Pd(1)
P(1)–S(2)–Pd(1)
126.01(18)
101.33(16)
130.74(18)
81.28(5)
a
Symmetry equivalent position (ꢁ1 + x, y, z) is given by ‘‘prime’’.
The P–N–S fragment is angular and the sum of the angles at the
nitrogen atom [356.7° in 1, 358.5° in 2a, 358.9° in 2b and 358.6° in
4, respectively] suggests a sp2 hybridization.
The conformation of the X@P(OEt)2–N–SO2–C skeleton can be
described by the torsion angles CSNP and XPNS, respectively (Ta-
ble 2), assigning the terms syn and anti to angles of 0° and 180°,
respectively. Thus the extreme conformations may be described
as syn–syn (D) and syn–anti (E) (Scheme 3) [40]. Thus, for the acid
1 a conformation close to syn–syn can be considered, with the
atoms C(1) and O(3) deviated at 1.571 and 0.3257 Å, respectively,
from the P(1)N(1)S(1) plane, while for compounds 2 and 4 a con-
formation close to syn–anti can be assigned [the deviations of
C(1) and O(3) and C(11) and O(8) are 1.644/0.092 Å in 2a and
1.693/0.189 Å in 2b from the planes P(1)N(1)S(1) and
By contrast, in compound 4 no intermolecular interactions were
observed.
3.2.1. Crystal and molecular structure of 12
The ORTEP-like diagram with the numbering scheme for the
palladium complex 12 is depicted in Fig. 6, while selected inter-
atomic distances and bond angles for this compound are given in
Table 3. The two ligand units act as monometallic biconnective
Fig. 7. Ribbon-like polymeric chain in Pd[{SP(OEt)2}(O2SC6H4Cl-4)N]2 (12). Hydrogen atoms, excepting those involved in intermolecular interactions, are omitted for clarity.

74
D. Oltean et al. / Polyhedron 53 (2013) 67–75
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S,N bidentate moieties towards the metal center [S(2)–Pd(1)
2.3445(10) Å, N(1)–Pd(1) 2.038(3) Å cf. rcov(Pd,S) 2.32 Å, rvdW
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(R = Ph, Pri) [36,37].
R
R
R
R
The oxygen atoms of the RSO2 moiety are not involved in coor-
dination, the Pd–O distances being much longer than the sum of
the van der Waals radii of palladium and oxygen, e.g. Pd(1)–O(1)
3.498(6) Å vs.
RrvdW(Pd,O) 3.0 Å. This behavior is different in com-
parison with that one observed in several group 11 complexes with
related ligands, i.e. a monometallic biconnective S,O bidentate
coordination
in
[Au{(SPPh2)(O2SC6H4Me-4)N}(PPh3)]
[42],
[Cu{(SPPh2)(O2SMe)N}(PPh3)2]
and
[Cu{(SPPh2)(O2SC6H4Me-
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respectively [58], and they are slightly different from the corre-
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before [range 1.552(3)–1.577(4) Å] [41,42].
The four-membered rings PdNOS are almost planar, the phos-
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mean plane Pd(1)N(1)S(2). The molecules are associated in a rib-
bon-like polymer by weak intermolecular Clꢀ ꢀ ꢀH contacts
[H(9A2)ꢀ ꢀ ꢀCl(10) 2.857(3) Å, vs.
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4. Conclusions
Our studies demonstrate that anionic species of type
[{XP(OEt)2}(O2SR)]Nꢁ can serve as bidentate ligands towards palla-
dium(II). NMR studies suggest either a S,O- or a S,N-bidentate coor-
dination pattern in solution for such species, while for complex 12
a S,N-coordination pattern was found in solid state. Single-crystal
X-ray diffraction studies revealed different association degrees in
case of the free acids [{OP(OEt)2}(O2SR)]NH, i.e. dimmers in com-
pound 2 (R = Ph) and a 3D layered structure in 1.
Acknowledgements
Financial support from the Ministry of Education and Research
of Romania (CNCS, Research Project No. PN-II-ID-PCE-2011-3-
0659) is greatly appreciated. D.O. thanks the European Social Fund
for a Scholarship (Education and Training Program 2008-2013,
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Appendix A. Supplementary data
CCDC 895658, 893795, 893794 and 893796 contain the supple-
mentary crystallographic data for 1, 2, 4 and 12. These data can be
obtained free of charge via http://www.ccdc.cam.ac.uk/conts/
retrieving.html, or from the Cambridge Crystallographic Data Cen-
tre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: +44 1223 336
033; or e-mail: deposit@ccdc.cam.ac.uk. Supplementary data asso-
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