Studies on zinc(II) complexes with N-thioacylamidophosphates: X-ray crystal structure of the [Zn(RC(S)NP(O)(OiPr)2)2] (R = NH2, tBuNH, c-C6H11NH)

Article abstract of DOI:10.1016/j.poly.2008.03.005

The photoluminescent properties of 17 zinc(II) chelates [Zn(RC(S)NP(O)(OiPr)₂-O,S)₂] (R = Ph (1a), PhNH (1b), p-BrPh (1c), p-MeOC₆H₄NH (1d), p-BrC₆H₄NH (1e), NH₂ (1f), iPrNH (1g), tBuNH (1h), Et₂N (1i), c-C₅H₁₀N (1j), c-OC₄H₈N (1k), c-C₆H₁₁NH (1l), aminobenzo-15-crown-5 (1m)) and [Zn(B)(RC(S)NP(O)(OiPr)₂-O,S)₂] (R = Ph, B = 2,2′-bipyridine (2a); R = Ph, B = 1,10-phenanthroline (2b); R = PhNH, B = 2,2′-bipyridine (2c); R = PhNH, B = 1,10-phenanthroline (2d)), are reported. Colorless and air/moisture stable chelate complexes of divalent zinc show blue emission in the solid state when excited with UV light. Complexes 1f, 1h, 1l were investigated by single crystal X-ray diffraction. The zinc(II) atom in complexes 1f, 1h, 1l is in a distorted tetrahedral O₂S₂ environment formed by the C{double bond, long}S sulphur atoms and the P{double bond, long}O oxygen atoms of two deprotonated ligands.

Full text of DOI:10.1016/j.poly.2008.03.005

Polyhedron 27 (2008) 2022–2028
Contents lists available at ScienceDirect
Polyhedron
journal homepage: www.elsevier.com/locate/poly
Studies on zinc(II) complexes with N-thioacylamidophosphates: X-ray crystal
structure of the [Zn(RC(S)NP(O)(OiPr)2)2] (R = NH2, tBuNH, c-C6H11NH)
a
b
a
a
Damir A. Safin a, , Felix D. Sokolov , Heinrich Nöth , Maria G. Babashkina , Timur R. Gimadiev ,
*
Joanna Galezowska c, Henryk Kozlowski c
a A.M. Butlerov Chemistry Institute, Kazan State University, Kremlevskaya Street 18, 420008 Kazan, Russia
b Department für Chemie der Universität München, Butenandtstrasse 5-13 (Haus D), 81377 München, Germany
c University of Wroclaw, Faculty of Chemistry, 50-383 Wroclaw, Poland
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 27 September 2007
Accepted 12 March 2008
The photoluminescent properties of 17 zinc(II) chelates [Zn(RC(S)NP(O)(OiPr)2-O,S)2] (R = Ph (1a), PhNH
(1b), p-BrPh (1c), p-MeOC6H4NH (1d), p-BrC6H4NH (1e), NH2 (1f), iPrNH (1g), tBuNH (1h), Et2N (1i),
c-C5H10
N
(1j), c-OC4H8N (1k), c-C6H11NH (1l), aminobenzo-15-crown-5 (1m)) and [Zn(B)
(RC(S)NP(O)(OiPr)2-O,S)2] (R = Ph, B = 2,20-bipyridine (2a); R = Ph, B = 1,10-phenanthroline (2b);
R = PhNH, B = 2,20-bipyridine (2c); R = PhNH, B = 1,10-phenanthroline (2d)), are reported. Colorless and
air/moisture stable chelate complexes of divalent zinc show blue emission in the solid state when excited
with UV light. Complexes 1f, 1h, 1l were investigated by single crystal X-ray diffraction. The zinc(II) atom
in complexes 1f, 1h, 1l is in a distorted tetrahedral O2S2 environment formed by the C@S sulphur atoms
and the P@O oxygen atoms of two deprotonated ligands.
Keywords:
Organoelement analogues of b-dicarbonyl
ligands
(Thioacylamido)phosphates
Zn(II) chelates
Heteroligand complexes
1,10-Phenanthroline
2,20-Bipyridine
Ó 2008 Elsevier Ltd. All rights reserved.
1. Introduction
netic and photophysical properties. The 1,5-X,S-coordination of
these ligand anions is typical for chelate complexes (e.g. [4–6]).
Up to now, large numbers of coordination complexes of the
Zn(II) cation have been prepared by taking certain factors into ac-
count, such as the functionality, flexibility, symmetry and nature of
donor centers of organic ligands and the coordination ability of the
metal ion [1]. Among these, the construction of complexes with
changeable geometry and structure, to the best of our knowledge,
has become a widely propagated and popular subject. Such com-
plexes are important in advanced materials such as optical devices,
especially with luminescence properties [2]. One of the effective
strategies to vary luminescent activity is to change the geometry
and structure. This requires the synthesis of complexes by addition
of a heteroligand to homoligand luminescence active complexes.
These compounds might find applications as receptors with optical
detecting properties.
However, recent investigations have shown that the coordina-
tion mode of these ligands containing the RNH group towards
Ni(II), Pd(II), Pt(II) [7,8], Cu(II) [9] and Cd(II) [10] cations depends
on the presence of strong intramolecular NHꢀ ꢀ ꢀO@P or NHꢀ ꢀ ꢀO@C
bonds. The thiourea ligands of common formula RNHC(S)NHP(O)
(OR0)2 (NPTU) [8,9] are able to bind Ni(II), Pd(II) and Cu(II) cations
through the C@S sulfur and P–N nitrogen atoms. The thiourea
nPrNHC(S)NHC(O)nPr [7] forms similar 1,3-N,S-chelate with the
Pt(II) cation through the C@S sulfur and NC(O) nitrogen atoms.
Interestingly, the N-(o-nitrophenyl)-N0-(methoxycarbonyl)thio-
urea (HQ) in complex of formula [Cd(2,20-bpy)Q2] is also bound
in the 1,3-N,S-fashion via the C@S sulfur and NC(O) nitrogen atoms
[10]. However, the sulfur atom of the thiourea HQ does not coordi-
nate to the Zn(II) ion. A monodentate coordination through the
deprotonated nitrogen atom of the C(S)NC(O) moiety occurs in
the chelate [Zn(2,20-bpy)Q2].
In the literature there is no information on crystal structure of
NPTU complexes with the Zn(II) cation. In this connection it was
interesting to investigate the structure and properties of some
complexes of phosphorylated thioureas and thioamides and com-
pares these with heteroligand analogues with participation of
2,20-bipyridine (bpy) and 1,10-phenanthroline (phen) as additional
donor ligands.
The late transition metal ion complexes of N-acylthioureas
R2NC(S)NHC(O)R0 [3] and their phosphoryl analogues based on
thioureas R2NC(S)NHP(O)(OR0)2 and thioamides RC(S)NHP(O)
(OR0)2 [4,5, and references therein] are of interest due to their mag-
* Corresponding author. Tel./fax: +7 843 2543734.
E-mail addresses: damir.safin@ksu.ru (D.A. Safin), felix.sokolov@ksu.ru (F.D.
Sokolov).
0277-5387/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved.
doi:10.1016/j.poly.2008.03.005

D.A. Safin et al. / Polyhedron 27 (2008) 2022–2028
2023
In this paper, we report on the photoluminescence properties at
room temperature of thirteen solid zinc-containing chelating com-
plexes with HL of composition Zn[RC(S)NP(O)(OiPr)2-O,S]2 (R = Ph
1a, PhNH 1b, p-BrPh 1c, p-MeOC6H4NH 1d, p-BrC6H4NH 1e, NH2
1f, iPrNH 1g, tBuNH 1h, Et2N 1i, c-C5H10N 1j, c-OC4H8N 1k,
c-C6H11NH 1l, aminobenzo-15-crown-5 1m) and four novel heter-
oligand complexes of composition Zn(B)[RC(S)NP(O)(OiPr)2-O,S]2
(R = Ph, B = 2,20-bipyridine 2a; R = Ph, B = 1,10-phenanthroline 2b;
R = PhNH, B = 2,20-bipyridine 2c; R = PhNH, B = 1,10-phenanthro-
line 2d).
NH2), 5.97 (br. s, 1H, NH2). 31P{1H} NMR (CDCl3): 6.2 ppm. IR
(cmꢁ1): 992 (b, vs) (POC); 1132 (vb, s) (P@O); 1512 (s) (SCN);
1620 (s), 3136 (b, s), 3272 (s); 3496 (s) (NH2). Anal. Calc. for
C14H32N4O6P2S2Zn (542.05): C, 30.92; H, 5.93; N, 10.30. Found: C,
30.90; H, 5.91; N, 10.33%.
2.3. Synthesis of [Zn(B)L2] (2a–2d)
A solution of complexes 1a (0.30 g, 0.45 mmol) or 1b (0.31 g,
0.45 mmol) in benzene (10 mL) was added dropwise whilst stirring
to a solution of 2,20-bipyridine (0.07 g, 0.45 mmol) or 1,10-phenan-
throline (0.08 g, 0.45 mmol) in benzene (10 mL). After complete
addition, the solution was stirred for an hour. The solvent was then
removed in vacuo. The residue was recrystallized from a methy-
lene chloride/n-hexane mixture. The complexes 2a-2d were iso-
lated as colorless powders.
2. Experimental
2.1. Physical measurements
Infrared spectra (Nujol) were recorded on a Specord M-80 spec-
trometer in the range 400–3600 cmꢁ1. NMR spectra were obtained
on a Varian Unity-300 NMR spectrometer at 25 °C. 1H and 31P{1H}
spectra were recorded at 299.948 and 121.420 MHz, respectively.
Chemical shifts are reported with reference to SiMe4 (1H) and
2.3.1. [Zn(2,20-bpy)(PhC(S)NP(O)(OiPr)2)2] (2a)
Yield: 0.28 g (75%), m.p. 102 °C. 1H NMR (CDCl3): d (ppm) = 1.36
3
3
3
(d, JH,H = 6.1 Hz, 24H, CH3), 4.74 (d. sept, JPOCH ꢂ JH,H ꢂ 6.5 Hz,
4H, OCH), 7.21–8.76 (m, 18H, C6H5 + bpy). 31P{1H} NMR (CDCl3):
5.9 ppm. IR (cmꢁ1): 996 (b, vs) (POC); 1168 (b, s) (P@O); 1464 (s)
(SCN). EI-MS: m/z (%) = 665 (73) [ZnL2]+, 301 (61) [HL]+, 156 (13)
[bpy]+. ES (positive ion): m/z (%) = 522.2 (100) [MꢁPhC(S)NP(O)
(OiPr)2]+. Anal. Calc. for C36H46N4O6P2S2Zn (820.16): C, 52.59; H,
5.64; N, 6.81. Found: C, 52.62; H, 5.60; N, 6.78%.
H3PO4 (
31P{1H}). Electron ionization mass spectra were measured
on the TRACE MS Finnigan MAT instrument. Ionization energy
was 70 eV. The substance was injected directly into the ion source
at 150 °C. Heating was carried out in a programmed mode from 35
to 200 °C at a rate of 35 °C/min. Electrospray ionization mass spec-
tra were measured with a Finnigan-Mat TCQ 700 mass spectrome-
ter on a 10ꢁ6 M solution in CH3OH. The speed of a sample
submission was 2 lL/min. The ionization energy was 4.5 kV. The
capillary temperature was 200 °C. Fluorescence measurements
were made on a SLM Aminco 500 spectrofluorometer at room tem-
perature. Elemental analyses were performed on a Perkin–Elmer
2400 CHN microanalyser. An ENRAF NONIUS four circle diffrac-
tometer, operating with Mo Ka radiation and a graphite monochro-
mator was used for determining the crystallographic parameters
and collecting the data sets.
2.3.2. [Zn(1,10-phen)(PhC(S)NP(O)(OiPr)2)2] (2b)
Yield: 0.31 g (82%), m.p. 154 °C. 1H NMR (CDCl3): d (ppm) = 1.32
3
3
3
(d, JH,H = 6.0 Hz, 24H, CH3), 4.72 (d. sept, JPOCH ꢂ JH,H ꢂ 6.5 Hz,
4H, OCH), 7.28–8.42 (m, 18H, C6H5 + phen). 31P{1H} NMR (CDCl3):
6.1 ppm. IR (cmꢁ1): 996 (b, vs) (POC); 1172 (b, s) (P@O); 1492 (s)
(SCN). EI-MS: m/z (%) = 665 (100) [ZnL2]+, 301 (29) [HL]+, 180
(54) [phen]+. ES (positive ion): m/z (%) = 546.3 (100)
[MꢁPhC(S)NP(O)(OiPr)2]+. Anal. Calc. for C38H46N4O6P2S2Zn
(844.16): C, 53.93; H, 5.48; N, 6.62. Found: C, 53.96; H, 5.51; N,
6.59%.
2.2. Synthesis of [ZnL2] (1a–1m)
2.3.3. [Zn(2,20-bpy)(PhNHC(S)NP(O)(OiPr)2)2] (2c)
Yield: 0.25 g (65%), m.p. 101 °C. 1H NMR (CDCl3):
d
Complexes 1a, 1b, 1d, 1e, 1g–1l were prepared according to the
previously described techniques [4,5,11].
(ppm) = 1.15–1.33 (m, 24H, CH3), 4.48–4.65 (m, 4H, OCH), 6.89–
8.46 (m, 18H, C6H5 + bpy), 8.58–8.63 (m, 2H, PhNH). 31P{1H}
NMR (CDCl3): 6.5 ppm. IR (cmꢁ1): 1008 (b, vs) (POC); 1140 (b, s)
(P@O); 1560 (s) (SCN); 3312 (NH). EI-MS: m/z (%) = 695 (22)
[ZnL2]+, 316 (100) [HL]+, 56 (74) [bpy]+. ES (positive ion): m/z
(%) = 537.3 (100) [MꢁPhNHC(S)NP(O)(OiPr)2]+. Anal. Calc. for
Complexes 1c and 1f were synthesized for the first time by the
method used in [4,5]. A suspension of HL, R = p-BrC6H4 (1.900 g,
5 mmol) or R = NH2 (1.200 g, 5 mmol) in aqueous ethanol (20 mL)
was mixed with an ethanol solution of potassium hydroxide
(0.28 g, 5 mmol). An aqueous (20 mL) solution of ZnCl2 (0.381 g,
2.8 mmol) was added dropwise under vigorous stirring at room
temperature for a further 3 h and left overnight. The resulting com-
plex was extracted with dichloromethane, washed with water and
dried with anhydrous MgSO4. The solvent was then removed in va-
cuo. A colourless precipitate was isolated from dichloromethane by
n-hexane.
C36H48N6O6P2S2Zn (850.18): C, 50.73; H, 5.68; N, 9.86. Found: C,
50.70; H, 5.72; N, 9.84%.
2.3.4. [Zn(1,10-phen)(PhNHC(S)NP(O)(OiPr)2)2] (2d)
Yield: 0.31 g (82%), m.p. 104 °C. 1H NMR (CDCl3):
d
(ppm) = 0.96–1.32 (m, 24H, CH3), 4.39–4.66 (m, 4H, OCH), 6.85–
8.45 (m, 18H, C6H5 + phen), 9.18–9.40 (m, 2H, PhNH). 31P{1H}
NMR (CDCl3): 6.6 ppm. IR (cmꢁ1): 1020 (b, vs) (POC); 1144 (b, s)
(P@O); 1504 (s) (SCN); 3288 (NH). EI-MS: m/z (%) = 695 (34)
[ZnL2]+, 316 (57) [HL]+, 180 (91) [phen]+. ES (positive ion): m/z
(%) = 561.2 (100) [MꢁPhNHC(S)NP(O)(OiPr)2]+. Anal. Calc. for
2.2.1. [Zn(p-BrC6H4C(S)NP(O)(OiPr)2)2] (1c)
Yield: 1.73 g (84%), m.p. 143 °C. 1H NMR (CDCl3): d (ppm) = 1.35
3
(d, 3JH,H = 5.6 Hz, 12 H, CH3), 1.36 (d, JH,H = 5.6 Hz, 12H, CH3), 4.71
3
3
(d. sept, JPOCH ꢂ JH,H ꢂ 6.2 Hz, 4H, OCH), 7.50 (m, 4H, o-H, C6H4),
8.14 (m, 4H, m-H, C6H4). 31P{1H} NMR (CDCl3): 6.9 ppm. IR
(cmꢁ1): 1000 (b, vs) (POC); 1152 (vb, s) (P@O); 1544 (s) (SCN). Anal.
Calc. for C26H36Br2N2O6P2S2Zn (823.85): C, 37.90; H, 4.40; N, 3.40.
Found: C, 37.86; H, 4.45; N, 3.38%.
C38H48N6O6P2S2Zn (874.18): C, 52.08; H, 5.52; N, 9.59. Found: C,
52.04; H, 5.47; N, 9.64%.
2.4. Crystal structure determination and refinement
2.2.2. [Zn(NH2C(S)NP(O)(OiPr)2)2] (1f)
The selected crystal was coerced with lithelene and mounted on
a glass fibre. It was then cooled to ꢁ60 °C on the goniometer head
of a Kappa Nonius diffractometer operated with a rotating anode.
After alignment the unit cell parameters were calculated from a se-
Yield: 1.24 g (91%), m.p. 182 °C. 1H NMR (CDCl3): d (ppm) = 1.29
3
3
(d, JH,H = 6.2 Hz, 12H, CH3), 1.30 (d, JH,H = 6.2 Hz, 12H, CH3), 4.58
3
3
(d. sept, JPOCH = 7.6 Hz, JH,H = 6.2 Hz, 4H, OCH), 5.81 (br. s, 1H,

2024
D.A. Safin et al. / Polyhedron 27 (2008) 2022–2028
lected data set, and data collection was performed by using an area
detector. For data reduction the program SMART was used, and for
structure solution and refinement the program package SHELXTL
PLUS. All plots of the molecules are shown with a 50% probability
for the thermal ellipsoids. The numbering of the atoms is shown in
Figs. 1–3 (ORTEP) [12] (see Table 1).
3. Results and discussion
3.1. Synthesis
Complexes 1a–1m were prepared by the following procedure:
the ligand was converted to the potassium salt, followed by reac-
tion with ZnCl2 (Scheme 1). The compounds obtained are crystal-
line solids soluble in most polar solvents.
Unsaturation of the ZnO2S2 coordination environment opens up
possibilities for the synthesis of a large number of heteroligand
complexes. They are obtained by the interaction of these com-
plexes with various donor agents.
In order to obtain the heteroligand complexes, we have com-
bined HL and two aromatic chelate ligands, (2,20-bipyridine or
1,10-phenanthroline) in experiments based on the following con-
siderations: (i) the steric hindrance at the metal center will be in-
creased when the aromatic 1,4-donor ligand binds to the metal
ion; this ensures the formation of the lower dimensional structure
and on the other hand (ii) metal complexes of 2,20-bipyridine or
1,10-phenanthroline and their derivatives exhibit excellent lumi-
nescent properties [13], which can be used not only as efficient
blue emitters in electroluminescent devices but also as chemical
sensors for specific organic molecules [14].
Complexes 2a–2d were prepared by the following procedure: a
benzene solution of 2,20-bipyridine or 1,10-phenanthroline was
added dropwise to a benzene solution of 1a or 1b (Scheme 1).
The compounds obtained 2a–2d are crystalline solids soluble in
most polar solvents.
Fig. 1. An ORTEP view of [Zn(H2NC(S)NP(O)(OiPr)2)2] (1f). Displacement ellipsoids
are drawn at the 50% probability level.
3.2. IR and NMR spectroscopy
It is shown that all listed complexes 1a–1m have a similar coor-
dination environment at the zinc atom. The IR, 1H, 31P{1H} NMR
[4,11] and X-ray [4] data confirm that in a CDCl3 solution and in
the solid state only [ZnL2] chelates with a tetrahedral ZnO2S2 core
exist. The 1,5-O,S-coordination appears to be the most steric favor-
able in this case because it provides a maximal bite angle for the
ligand’s anionic form Lꢁ.
The additional ligands bpy or phen in a molecule of complex
could affect on the coordination mode of the anionic thiourea li-
gands. The bond angles in the cation environment decrease in com-
parison with the tetrahedral core and requirements to the bite
angle are softened, thus the situation becomes ambiguous. The
structures of the thiourea HQ chelates with the Zn(II) and Cd(II)
cations demonstrate the examples of such changes in the coordina-
tion modes [10].
Fig. 2. An ORTEP view of [Zn(tBuNHC(S)NP(O)(OiPr)2)2] (1h). Displacement ellip-
soids are drawn at the 50% probability level.
There is
a strong (20–25 kJ/mol) hydrogen bond of type
PhNHꢀ ꢀ ꢀO@P in the thiourea PhNHC(S)NHP(O)(OiPr)2 and its com-
plexes [8,9]. It prevents the coordination through the P@O group in
square planar complexes of the Ni(II), Pd(II) and Cu(II) cations.
Thus, the presence the bpy or phen in the coordination sphere
of Zn(II) makes possible the three coordination modes of
PhNHC(S)NHP(O)(OiPr)2 (HL): (i) preservation of the 1,5-O,S-coor-
dination for Lꢁ (Scheme 2A); (ii) 1,3-N,S-coordination of Lꢁ
(Scheme 2B); (iii) monodentate N-coordination (Scheme 2C). Nei-
ther of them could be discarded a priori.
The 1,5-O,S-coordination (Scheme 2A) is a unique variant is for
complexes of the thioamide PhC(S)NHP(O)(OiPr)2 due to absence of
the intramolecular H-bonds.
Unfortunately, we could not get suitable crystals of complexes
2a–2d, for X-ray structure analysis. However, according to the IR,
1H, 31P{1H} NMR and luminescence data, obtained in a CDCl3 solu-
tion and in the solid state, complexes 2a–2d have a ZnO2S2N2 core
(Scheme 2A). The comparative analysis of IR spectra of the initial
ligands RC(S)NHP(O)(OiPr)2 (R = Ph and PhNH), their complexes
Fig. 3. An ORTEP view of [Zn(c-C6H11NHC(S)NP(O)(OiPr)2)2] (1l). Displacement el-
lipsoids are drawn at the 50% probability level.

D.A. Safin et al. / Polyhedron 27 (2008) 2022–2028
2025
Table 1
Crystal data and data collection parameters for 1f, 1h and 1l
Compound
1f
1h
1l
Chemical formula
Formula weight
Crystal size (mm)
Crystal system
Space group
a (Å)
C
14H32N4O6P2S2Zn
C22H48N4O6P2S2Zn
656.11
0.22 ꢃ 0.30 ꢃ 0.35
monoclinic
Cc
24.776(5)
9.350(2)
14.476(3)
98.41(3)
3317.3(12)
4
C26H52N4O6P2S2Zn
708.19
0.15 ꢃ 0.21 ꢃ 0.25
monoclinic
P21/c
14.912(5)
17.531(5)
15.153(5)
115.410(5)
3578(2)
543.91
0.06 ꢃ 0.14 ꢃ 0.19
monoclinic
P21/n
15.9479(4)
9.1698(2)
17.4946(4)
104.0098(1)
2482.29(10)
4
b (Å)
c (Å)
b (°)
V (Å3)
Z
4
q(calc.) (Mg/m3)
1.455
1.321
1136
1.314
1.001
1392
1.315
0.933
1504
l (mmꢁ1
F(000)
)
Index range
2h (°)
ꢁ18 6 h 6 18, ꢁ10 6 k 6 10, ꢁ20 6 l 6 20
ꢁ30 6 h 6 30, ꢁ11 6 k 6 11, ꢁ17 6 l 6 17
ꢁ18 6 h 6 18, ꢁ21 6 k 6 20, ꢁ18 6 l 6 18
50.02
200
52.22
193
52.02
193
Temperature (K)
Reflections collected
Reflections unique
Reflections observed (4r)
R(int.)
Number of variables
Weight. schemea, x/y
Goodness-of-fit
Final R (4r)
8389
4358
3598
0.017
294
0.0511/1.1243
1.05
0.0337
0.0927
0.29
6192
6187
5724
0.005
337
0.0495/7.0103
1.01
0.0387
0.1028
0.43
13268
7020
5853
0.026
538
0.0500/0.8394
1.02
0.0319
0.0882
0.38
Final wR2
Larg. res. peak (e/Å3)
a
w
ꢁ1 = r2F2o + (xP)2 + yP; P = (F2o + 2F2c)/3.
H
O
N
R
R'
R'
H
O
N
R'
Pri O
P
HL
P
Ph
N
S
P
Pri O
N
R'
R
S
O
S
R
S
S
Ph
H
1) KOH
2) ZnCl2
N
Zn
N
Zn
N
N
O
N
O
P
N
R'
N
R'
R'
R
P
OiPr
R'
S
Pri O
P
O
1a-m
2a-d
N
N
Zn
S
Ph
O
P
OiPr
OiPr
R
R'
O
S
S
N
H
N
P
H
B
R'
N
N
O
R'
Ph
P
[Zn(B){RC(S)NP(O)(OiPr)2}2]
R = Ph, PhNH
Zn
R'
N
N
B:
or
N
N
N
N
N
N
N
N
N
N
Scheme 1.
Scheme 2. Proposed modes of the ligand coordination in complexes [Zn(B)L2] (2).
R0 = OiPr.
with the Zn(II) cation 1a and 1b, and adducts 2a–2d confirms the
preservation of the 1,5-O,S-coordination in the [ZnL2] core of 2a–
2d.
There is a series of the P@O group absorption bands in the IR
spectra of complexes 2a–2d in the area close to the appropriate
1,5-O,S-chelate complexes of type [ML2] [4–6], and there is also
an intense absorption band of the SCN fragment. This confirms
the 1,5-O,S-coordination of the ligand anions.
It is important to note, that the band of the PhNH group in 2c,
2d is in the field of 3288–3312 cmꢁ1, which is characteristic for

2026
D.A. Safin et al. / Polyhedron 27 (2008) 2022–2028
Table 2
1,5-O,S-isomers, showing the weak intermolecular H-bonding in
the solid state [5,8]. The isomers B and C must have the NH-group
absorption band up to 3100–3160 cmꢁ1 [8] due to formation of the
strong intramolecular hydrogen bond (Scheme 2).
Selected bond distances (Å) bond and torsion angles (°) for six-membered cycles Zn–
S–C–N–P–O in complexes 1f, 1h and 1la
Complexes of general formula [ZnL2]
The 31P{1H} NMR signals of complexes 2a–2d appear at d = 5.9–
6.7 ppm, i. e. there is a down-field shift relative to that of the free
ligand RC(S)NP(O)(OiPr)2 (R = Ph, d = ꢁ5.6 ppm and PhNH,
d = ꢁ5.3 ppm). Full width at half peak heights is in the range 3.0–
9.0 Hz. However, the shift of the signals in 2a–2d is more than
0.2–0.4 ppm, compared to the complexes 1a and 1b [11]. The sig-
nals are in the region that is characteristic to the amidophosphate
environment in complexes of N-acylamidophosphate anions.
The 1H NMR spectra of complexes 2a–2d contain a set of signals
for the (iPrO)2P(O) and C6H5 protons. There are also signals corre-
sponding to the polyaromatic chelate ligand. Analysis of the inte-
gral intensities of the proton signal testifies about complexes 2a–
2d structure of [Zn(2,20-bpy)L2] (2a, 2c) or [Zn(1,10-phen)L2]
(2b,2d).
1f
1h
1l
Zn–O
1.957(2)
1.954(2)
1.964(3)
1.948(3)
1.973(2)
1.973(2)
Zn–S
2.2945(9)
2.2890(8)
2.2894(12)
2.2850(11)
2.3077(9)
2.2970(9)
C–S
1.749(2)
1.751(2)
1.767(4)
1.752(4)
1.770(2)
1.766(2)
(S)C–N
1.315(3)
1.314(3)
1.314(5)
1.302(5)
1.310(3)
1.303(3)
(S)C–N (exocyclic)
P–N
1.329(4)
1.334(4)
1.349(4)
1.338(4)
1.331(3)
1.330(3)
1.598(2)
1.606(2)
1.603(3)
1.599(4)
1.602(2)
1.593(2)
P–O
1.494(2)
1.496(2)
1.495(3)
1.492(3)
1.4996(14)
1.4961(14)
Thus, IR and NMR spectroscopy data confirm the structure of
the adducts 2a–2d in solution and solid state. The donor polyaro-
matic ligands, as well as anionic ligands, are coordinated to the
Zn(II) cation.
S–Zn–O (endocyclic)
P–N–C–S
O–P–N–C
Zn–S–C–N
N–P–O–Zn
S–Zn–O–P
O–Zn–S–C
a
109.53(6)
102.00(6)
103.00(9)
101.89(9)
101.38(4)
99.70(4)
3.5(4)
4.5(4)
ꢁ7.0(6)
ꢁ8.0(7)
32.6(4)
ꢁ13.5(5)
176.3(2)
16.1(4)
7.8(3)
3.5(3)
3.3. EI mass spectrometry
ꢁ17.1(3)
ꢁ25.9(3)
11.7(3)
11.0(3)
ꢁ45.3(2)
ꢁ23.8(3)
29.1(2)
26.5(2)
Molecular ions of complexes 2a–2d are unstable under the con-
ditions of measurement, and the heaviest molecular ion, observed
in the spectra of 2a–2d, corresponds to the neutral [ZnL2] complex
core. In the EI mass spectra there are also peaks of the parent
amidophosphate ligands, 2,20-bipyridine and 1,10-phenanthroline,
respectively.
10.4(2)
27.0(2)
21.1(3)
ꢁ42.9(3)
28.8(2)
ꢁ10.1(2)
ꢁ6.1(2)
ꢁ6.6(2)
29.50(14)
2.20(2)
3.20(14)
6.50(11)
ꢁ11.19(14)
ꢁ12.49(11)
ꢁ6.77(11)
23.41(12)
ꢁ31.18(9)
ꢁ33.51(9)
3.4. Molecular structure of ZnL2 complexes 1f, 1h, 1l
Presented data relate to the two independent ligand moieties with P(1) and P(2)
atoms, respectively.
According to the X-ray data complexes 1f, 1h, 1l are spirocy-
cling bis-chelates with a distorted-tetrahedral ZnO2S2 core. All
complexes contain structurally independent ligand moieties. The
selected bond lengths and torsion angles are given in Table 2. Inter-
molecular hydrogen bond parameters are given in Table 3.
Bond lengths (S)C–N and P–N in complexes are shortened
(Table 2) and the C@S and P@O(Zn) distances are considerably
lengthened in comparison with typical interatomic distances re-
ported for N-phosphorylated thioureas [6]. The bond lengths distri-
bution in the ligand moieties confirms the superiority of S-enolic
tautomeric form S–C@N–P@O for all compounds.
Six-membered Zn–O–P–N–C–S cycles have the asymmetrical
boat conformation. The maximal deviation of atoms from the least
square plane (LSP) of the cycles is observed for the phosphorus,
sulphur and zinc atoms. Chelate cycles in 1f are almost planar;
the deviation from LSP is the smallest among the presented
structures.
Table 3
Intermolecular hydrogen bond parameters for 1f, 1h and 1l
D–Hꢀ ꢀ ꢀA
1f
D–H
Hꢀ ꢀ ꢀA
Dꢀ ꢀ ꢀA
D–Hꢀ ꢀ ꢀA
N(2)–H(2N)ꢀ ꢀ ꢀN(3)#a
N(4)–H(4N)ꢀ ꢀ ꢀN(1)#b
1h
0.83(3)
0.83(3)
2.30(3)
2.20(3)
3.131(3)
3.007(3)
175(3)
166(3)
N(1)–H(1N)ꢀ ꢀ ꢀS(2)#c
N(3)–H(3N)ꢀ ꢀ ꢀS(1)#d
1l
1.02(4)
0.68(5)
2.56(4)
2.87(5)
3.559(4)
3.536(4)
169(3)
167(4)
N(2)–H(2)ꢀ ꢀ ꢀS(2)#e
0.80(2)
0.78(3)
2.65(2)
2.77(3)
3.400(2)
3.531(2)
158(2)
166(2)
N(4)–H(4)ꢀ ꢀ ꢀS(1)#f
a
[ꢁ1/2 + x, 1/2 ꢁ y, ꢁ1/2 + z].
[1/2 + x, 1/2 ꢁ y, 1/2 + z].
[x, 1 ꢁ y, ꢁ1/2 + z].
b
c
d
e
f
[x, 1 ꢁ y, 1/2 + z].
Complexes 1f, 1l show a remarkably different H-bonding pat-
tern in the crystal (Scheme 3). Molecules of 1f are connected to
endless chains by H-bonds between the NH2 group proton and
the nitrogen atom of the N–P group. The chelates 1h and 1l form
hydrogen-bonded chains with the RNH proton and the sulphur
atom of neighbor chelate molecule.
[x, 1/2 ꢁ y, ꢁ1/2 + z].
[x, 1/2 ꢁ y, 1/2 + z].
4 and Fig. 4). Complexes 2a–2d give a strong blue emission band
at 413–419 nm when irradiated at wavelength 249 nm (Table 4
and Fig. 4). In order to understand the nature of these emission
bands, we analyzed the photoluminescence properties of free HL.
For excitation wavelengths between 300 and 500 nm, there is no
obvious emission observed for free HL under the same experimen-
tal conditions. Therefore, the fluorescent emissions in the com-
pounds 1a–1m are proposed to originate from the coordination
of two Lꢁ to the zinc atom and according to the literature [15],
these emission bands can be assigned to the emission of ligand-
to-metal charge transfer (LMCT).
3.5. Photoluminescent properties
The data of the emission spectra for complexes 1a–1m and 2a–
2d in the solid state at room temperature are listed in Table 4 (note
that the parent ligands have no emission). Interestingly, they exhi-
bit practically the same fluorescent properties.
Complexes 1a–1m show a blue emission band with the maxi-
mum intensity at 394–399 nm upon excitation at 249 nm (Table

D.A. Safin et al. / Polyhedron 27 (2008) 2022–2028
2027
phen ligands in the coordination sphere of the Zn(II) cation allows
increasing the emission that might be easily used in non-linear
optical devices.
H
N
R'
P
R'
H
P
O
Zn
S
H
S
N H
N
N
R'
P O
S
R'
N
O P
R'
S
R'
4. Conclusion
N
H N
Zn
H
O
H
N
N-Phosphorylated thioamides and thioureas HL form with the
Zn(II) cation only [ZnL2] chelates with a tetrahedral ZnO2S2 core.
1,5-O,S-Coordination of the deprotonated form of the ligand, gen-
erating a maximal bite angle for Lꢁ, appears as much as possible
favorable on the steric reasons.
The ZnO2S2 core in these complexes shows a coordination
unsaturation. The [ZnL2] complexes tends to increase the coordina-
tion number of the central atom with neutral donor ligands like
2,20-bipyridine or 1,10-phenanthroline. The adducts of common
formula [Zn(bpy)L2] and [Zn(phen)L2] have been obtained and
characterized. The preservation of the 1,5-O,S-coordination mode
of Lꢁ in the adducts have been established on the basis of the IR
and NMR data comparison.
R'
R'
H
R'
R'
R
H
N P
R
R'
N
N
O
N
R'
N
H
P
Zn
S
O
Zn
S
S
O
H
S
H
R'
P
N
R
N
O
R'
P
N
R
R'
R'
Scheme 3. Intermolecular hydrogen bonds patterns in a crystal of 1f (A) and 1h
(R = tBu), 1l (R = c-C6H11) (B). R0 = OiPr.
Luminescent zinc N-thioacylamidophosphates can be used as
new light-converting molecular devices since they (i) are air/mois-
ture stable, (ii) show luminescent properties in the solid state, and
at the same time (iii) ligands can be easily prepared from widely
used amines and isothiocyanates [4,11].
Table 4
Photophysical data for complexes 1a–1m and 2a–2da
Emission max (nm)
Emission max (nm)
Acknowledgements
1a
1b
1c
1d
1e
1f
1g
1h
1i
394
397
395
398
398
397
398
399
398
1j
1k
1l
1m
2a
2b
2c
2d
398
399
399
398
415
418
413
419
We thank Dr. P. Mayer for collecting the data sets for the crystal
structure determination. This work was supported by the joint pro-
gram of CRDF and the Russian Ministry of Education and Science
(BRHE 2004 Y2-C-07-02 and BRHE 2008 Y5-C-07-09); Russian Sci-
ence Support Foundation.
a
Excitation at 249 nm.
Appendix A. Supplementary data
CCDC 646784–646786 contain the supplementary crystallo-
graphic data for 1f, 1h and 1l, respectively. These data can be ob-
tained 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-
ciated with this article can be found, in the online version, at
doi:10.1016/j.poly.2008.03.005.
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