Transesterification reactions of dimethoxycarbonylethyltin- morpholinodithiocarbamate, [(MeO2CCH2CH2)2Sn(MDTC)2]: Synthesis, spectroscopy, X-ray structural characterization and DFT calculations of new diestertin dithiocarbamate complexes – Part II

Article abstract of DOI:10.1016/j.poly.2017.06.046

The scarcity of studies concerning diestertin(IV) dithiocarbamate complexes led us to investigate the spectroscopic and structural properties of [(RO₂CCH₂CH₂)₂Sn(MDTC)₂] (R?=?Me (1) or Et (2); MDTC?=?morpholinodithiocarbamate). The reaction of [(MeO₂CCH₂CH₂)₂SnCl₂] with sodium morpholinodithiocarbamate (NaMDTC) in CHCl₃ afforded (1), while the transesterification reaction of (1) with EtOH in the presence of dmso yielded (2). Both diestertin(IV) complexes were characterized by elemental analysis, FTIR and multinuclear (¹H, ¹³C and ¹¹⁹Sn) NMR spectroscopy, and single-crystal X-ray diffraction. Our X-ray structural analysis revealed that (1) and (2) exhibit a distorted pentagonal bipyramidal coordination geometry. In both cases, the apical positions are occupied by ester groups while the equatorial plane displays two bidentate morpholinodithiocarbamate ligands and one intramolecular C[dbnd]O?Sn interaction. The O?Sn distances amount to 2.632 (1) and 2.618?? (2). According to our supramolecular analysis, the crystal arrangement of each product is assembled by weak C–H?O and C–H?S hydrogen bonds. Finally, a DFT study of the six- and seven-coordinate forms of (1) and (2) allowed an upper-bound estimate of the intramolecular C[dbnd]O?Sn interaction energy, ?3.7?kcal?mol^?1.

Full text of DOI:10.1016/j.poly.2017.06.046

Accepted Manuscript
Transesterification reactions of dimethoxycarbonylethyltin- morpholinodithio-
carbamate, [(MeO2CCH2CH2)2Sn(MDTC)2]: Synthesis, spectroscopy, X-ray
structural characterization and DFT calculations of new diestertin dithiocarba-
mate complexes - Part II
B.P. de Morais, C.L. Donnici, B.L. Rodrigues, G.M. de Lima, J.L. Wardell,
M.A.C. Nascimento, R.S. Bitzer
PII:
S0277-5387(17)30464-3
DOI:
http://dx.doi.org/10.1016/j.poly.2017.06.046
POLY 12727
Reference:
Polyhedron
To appear in:
Received Date:
Accepted Date:
10 April 2017
28 June 2017
Please cite this article as: B.P. de Morais, C.L. Donnici, B.L. Rodrigues, G.M. de Lima, J.L. Wardell, M.A.C.
Nascimento, R.S. Bitzer, Transesterification reactions of dimethoxycarbonylethyltin- morpholinodithiocarbamate,
[(MeO2CCH2CH2)2Sn(MDTC)2]: Synthesis, spectroscopy, X-ray structural characterization and DFT calculations
of new diestertin dithiocarbamate complexes - Part II, Polyhedron (2017), doi: http://dx.doi.org/10.1016/j.poly.
2017.06.046
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers
we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and
review of the resulting proof before it is published in its final form. Please note that during the production process
errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Transesterification reactions of dimethoxycarbonylethyltin-
morpholinodithiocarbamate, [(MeO2CCH2CH2)2Sn(MDTC)2]: Synthesis,
spectroscopy, X-ray structural characterization and DFT calculations of
new diestertin dithiocarbamate complexes - Part II
B.P. de Morais a, C.L. Donnici a, B.L. Rodrigues a, G.M. de Lima a,*,
J.L. Wardell b, c, M.A.C. Nascimento d, and R.S. Bitzer d,*
a Departamento de Química, Universidade Federal de Minas Gerais, UFMG, Avenida Antônio Carlos 6627,
Belo Horizonte, MG, 31270-901, Brazil
b Fiocruz - Fundação Oswaldo Cruz, Instituto de Tecnologia em Fármacos, Farmanguinhos, Rio de Janeiro,
RJ, 21041-250, Brazil
c Department of Chemistry, University of Aberdeen, Old Aberdeen, AB24 3UE, Scotland, UK
d Instituto de Química, Universidade Federal do Rio de Janeiro, UFRJ, Rio de Janeiro, RJ, 21941-909, Brazil
Abstract
The scarcity of studies concerning diestertin(IV) dithiocarbamate complexes led us to
investigate the spectroscopic and structural properties of [(RO2CCH2CH2)2Sn(MDTC)2] (R =
Me (1) or Et (2); MDTC
=
morpholinodithiocarbamate). The reaction of
[(MeO2CCH2CH2)2SnCl2] with sodium morpholinodithiocarbamate (NaMDTC) in CHCl3
afforded (1), while the transesterification reaction of (1) with EtOH in the presence of dmso
yielded (2). Both diestertin(IV) complexes were characterized by elemental analysis, FTIR
and multinuclear (1H, 13C and 119Sn) NMR spectroscopy, and single-crystal X-ray diffraction.
Our X-ray structural analysis revealed that (1) and (2) exhibit a distorted pentagonal
bipyramidal coordination geometry. In both cases, the apical positions are occupied by ester
groups while the equatorial plane displays two bidentate morpholinodithiocarbamate ligands
and one intramolecular C=O···Sn interaction. The O···Sn distances amount to 2.632 (1) and
2.618 Å (2). According to our supramolecular analysis, the crystal arrangement of each
product is assembled by weak C-H···O and C-H···S hydrogen bonds. Finally, a DFT study of
the six- and seven-coordinate forms of (1) and (2) allowed an upper-bound estimate of the
intramolecular C=O···Sn interaction energy, -3.7 kcal mol-1.
Keywords: Organotin dithiocarbamate; Estertin; Structural determination; Weak hydrogen
bond; DFT calculations.
* Corresponding authors: gmlima@ufmg.br (Prof. G.M. de Lima) and rodrigobitzer@gmail.com (Dr. R.S. Bitzer).
1

1. Introduction
In the middle of the 19th century, Sir Edward Frankland reported the synthesis of
diethyltin diiodide, giving rise to organotin chemistry [1,2]. After the discovery of Grignard
reagents, organotin chemistry evolved a great deal, consolidating itself as one of the most
prolific subareas of organometallic chemistry [3]. Nevertheless, biological and industrial
applications of organotin compounds only started to emerge a century after Frankland’s
seminal work [3-6]. Specifically, estertin(IV) compounds were introduced by AKZO Chemie
in the mid-1970s as more efficient and less toxic PVC stabilizers [7-9].
Monoestertin(IV) derivatives have received much attention in the literature. They
display a variety of coordination geometries due to the possibility of intramolecular
C=O···Sn interaction, as confirmed by X-ray structure analyses and theoretical calculations
[10-22]. Furthermore, monoestertin(IV) compounds readily undergo transesterification
reactions owing to the increased electrophilicity of the carbonyl group semi-coordinated to tin
[23-27].
Unlike monoestertins, examples of diestertin(IV) compounds are relatively limited
[11,16,28-38]. Under basic conditions, [(MeO2CCH2CH2)2SnCl2] eliminates MeOH yielding
di(carboxylethyl)tin, C6H8O4Sn, which can be converted into [(RO2CCH2CH2)2SnCl2] upon
dissolution in alcoholic HCl solutions [28]. In addition, [(MeO2CCH2CH2)2SnCl2] can
undergo salt metathesis reactions affording new bis(2-methoxycarbonylethyl)tin(IV)
derivatives [30,31,37,38]. Diestertin(IV) compounds can also go through transesterification
reactions [32,38]. In 2007, Dong reported the preparation of [(EtO2CCH2CH2)2SnCl2] by
reaction of [(MeO2CCH2CH2)2SnCl2] with EtOH [32]. Recently, we have shown that a series
of diestertin(IV) dithiocarbamate complexes can be easily obtained by transesterification
reactions in the presence of dmso [38].
As part of our ongoing interest in organotin chemistry [15,33,38-50], we have
undertaken a project aiming to elucidate spectroscopic and structural properties of
diestertin(IV) dithiocarbamate complexes [38]. Previous studies on these compounds deal
with seven-coordinated [(MeO2CCH2CH2)2Sn(S2CNR2)2] (R = Me or Et) [37,51] and
[(MeO2CCH2CH2)2SnCl(S2CNMe2)], which adopts a distorted trigonal bipyramidal
coordination geometry [52]. In addition, we have recently described the spectroscopic and
structural properties of [(RO2CCH2CH2)2Sn(PDTC)2] (R = Me, Et, Pr or Bu; PDTC =
pyrrolidinodithiocarbamate), in which the geometry at the metal centres is a distorted
pentagonal bipyramid [38]. In this article, we report the synthesis, spectroscopy, X-ray
structure and Hirshfeld surface analyses, and DFT study of [(RO2CCH2CH2)2Sn(MDTC)2] (R
2

= Me (1) or Et (2); MDTC = morpholinodithiocarbamate), extending our earlier work on the
subject [38]. This article shows that (1) and (2) also exhibit seven-coordinate Sn(IV) centres
due to intramolecular C=O···Sn interactions. Moreover, a DFT study of the six- and seven-
coordinate forms of (1) and (2) has allowed an estimate of the C=O···Sn interaction energy.
2. Computational and experimental details
2.1. Materials and instruments
Starting materials and reagent grade solvents were purchased from Aldrich, Alfa-
Aesar, Fluka, Merck, Synth or Vetec and used as received. The organotin(IV) precursor
[(MeO2CCH2CH2)2SnCl2] was prepared according to the literature [11,53], and NaMDTC
1
was obtained from morpholine, CS2 and NaOH. H and 13C{1H} NMR spectra in solution
were recorded at 200 and 50 MHz, respectively, using a Bruker DPX-200 spectrometer
13
equipped with an 89 mm wide-bore magnet. The C{1H} NMR spectra of (1) and (2) are
shown in Figure S1 (Appendix A). 119Sn{1H} NMR spectra were recorded at 400 MHz using
a Bruker Advance III DPX-400 spectrometer equipped with an 89 mm wide-bore magnet.
1
The 119Sn{1H} NMR spectra of (1) and (2) are depicted in Figure S2 (Appendix A). H and
13C{1H} chemical shift (δ/ppm) values were determined relative to SiMe4, and the 119Sn{1H}
δ values were determined relative to SnMe4. The FTIR spectra were recorded using KBr
pellets on a PerkinElmer 238 FTIR spectrometer. C, H and N microanalyses were performed
on a PerkinElmer PE-2400 CHN analyser. Single-crystal X-ray diffraction data were acquired
at 150(1) K using a Xcalibur Atlas Gemini ultra-diffractometer and graphite-monochromated
Mo-Kα radiation (λ = 0.71073 Å). Data collection, reduction and cell refinement were
performed with CrysAlisPro [54]. The crystal structures were solved by Direct Methods
using SHELXS-97 [55] and refined by full-matrix least squares on F2 using SHELXL-2014
[56]. All H atoms were geometrically positioned and refined as riding on their respective C
atoms. WinGX was used as graphical interface for structure solution and refinement [57].
The crystal structures were analysed with Mercury [58] and PLATON [59]. Material for
publication, including CIFs and molecular graphics, was prepared using Mercury [58] and
enCIFer [60]. Crystal data and structure refinement parameters for (1) and (2) are
summarized in Table I.
Insert Table I
3

Molecular Hirshfeld surfaces have been constructed from CIFs in order to dissect
crystal structures into noncovalent contacts [62-65]. The very high-resolution Hirshfeld
surfaces for (1) and (2) were generated by CrystalExplorer 3.1 [66], and functions of
curvature and distance, including shape index and dnorm, were mapped onto the surfaces. In
addition, two-dimensional fingerprint (di,de) plots were used to illustrate individual
intermolecular contributions to the crystal structures (Figures S3 and S4, Appendix A).
2.2. Synthesis of [(MeO2CCH2CH2)2Sn(MDTC)2] (1)
[(MeO2CCH2CH2)2SnCl2] (0.983 g, 2.70 mmol) dissolved in CHCl3 (10 mL) was
slowly added to a suspension of NaMDTC (1.10 g, 5.94 mmol) in the same solvent (20 mL).
After 24 h reflux, the solvent was pumped off and the remaining oily residue was washed
with Et2O, affording a white precipitate, which was recrystallized from a mixture of
MeOH:CH2Cl2:dmso (50:50:1). X-ray quality single crystals were grown as the solvent
mixture cooled to room temperature. Yield: 65% (0.872 g, 1.41 mmol). M.p.: 141-143°C.
Anal. Calc. for C18H30N2O6S4Sn (FW 617.37): C, 35.02; H, 4.90; N, 4.74%. Found: C, 35.08;
H, 4.58; N, 4.71%. FTIR (KBr, νmax/cm-1): 1740/1709 ν(CO); 1464 ν(CN); 1005 ν(CS);
1
560/547 ν(Sn-C). H NMR (CDCl3, δ/ppm): 4.05-4.03 {m, 4H, S2CN(CH2CH2)2O}, 3.71-
3.69 {m, 4H, S2CN(CH2CH2)2O}, 3.67 {s, 6H, Sn(CH2CH2CO2CH3)2}, 2.97 {t, 4H,
3
Sn(CH2CH2CO2Me)2, JH-H = 8.1 Hz, 3JSn-H = 113.6 Hz}, 2.25 {t, 4H, Sn(CH2CH2CO2Me)2,
2
3JH-H = 8.1 Hz; JSn-H = 92.9 Hz}. 13C NMR (CDCl3, δ/ppm): 202.1 {S2CN(CH2CH2)2O},
3
176.5 {Sn(CH2CH2CO2Me)2, JSn-C = 127.9 Hz}, 66.1 {S2CN(CH2CH2)2O}, 51.2
1
{S2CN(CH2CH2)2O}, 52.2 {Sn(CH2CH2CO2CH3)2}, 32.8 {Sn(CH2CH2CO2Me)2, JSn-C
=
804.8/768.9 Hz}, 30.8 {Sn(CH2CH2CO2Me)2, 2JSn-C = 40.1 Hz}. 119Sn NMR (CDCl3, δ/ppm):
-436.7 {1JSn-C = 804.3 Hz, 3JSn-C = 130.3 Hz}.
2.3. Synthesis of [(EtO2CCH2CH2)2Sn(MDTC)2] (2)
A round bottom flask (50 mL) was charged with (1) (0.881 g, 1.43 mmol) and a
mixture of EtOH (15 mL) and dmso (0.30 mL). After 30 min reflux, the resulting solution
was left standing at room temperature. X-ray quality crystals were obtained after 24 h. Yield:
61% (0.563 g, 0.872 mmol). M.p.: 93-94°C. Anal. Calc. for C20H34N2O6S4Sn (FW 645.42):
C, 37.22; H, 5.31; N, 4.34%. Found: C, 37.32; H, 5.21; N, 4.40%. FTIR (KBr, νmax/cm-1):
1
1731/1694 ν(CO); 1463 ν(CN); 1000 ν(CS); 562/543 ν(Sn-C). H NMR (CDCl3, δ/ppm):
4

4.12-4.05 {m, 4H, Sn(CH2CH2CO2CH2CH3)2}, 3.98 {m, 4H, S2CN(CH2CH2)2O}, 3.63 {m,
4H, S2CN(CH2CH2)2O}, 2.88 {t, 4H, Sn(CH2CH2CO2Et)2, 3JH-H = 8.0 Hz; 3JSn-H = 114.4 Hz},
3
2
2.16 {t, 4H, Sn(CH2CH2CO2Et)2, JH-H = 7.9 Hz, JSn-H = 93.8 Hz}, 1.16 {t, 6H,
3
Sn(CH2CH2CO2CH2CH3)2, JH-H = 7.0 Hz}. 13C NMR (CDCl3, δ/ppm): 202.1
{S2CN(CH2CH2)2O}, 175.9 {Sn(CH2CH2CO2Et)2, 3JSn-C
{S2CN(CH2CH2)2O}, 60.9 {Sn(CH2CH2CO2CH2CH3)2}, 51.0 {S2CN(CH2CH2)2O}, 32.8
{Sn(CH2CH2CO2Et)2}, 30.8 {Sn(CH2CH2CO2Et)2, 2JSn-C
42.8 Hz}, 14.1
=
127.7 Hz}, 65.9
=
{Sn(CH2CH2CO2CH2CH3)2}. 119Sn NMR (CDCl3, δ/ppm): -443.2 {1JSn-C = 812.6 Hz; 3JSn-C
=
123.1 Hz}.
2.4. DFT calculations
All calculations were carried out with JAGUAR 7.9 [67] using an energy convergence
criterion of 1.00 x 10–8 hartree. Gas-phase geometry optimizations were performed without
constraints using the B3LYP [68] hybrid functional along with the LACV3P** basis set. The
crystal structures of (1) and (2) were used as input geometries. Relative total energies
(∆ET/kcal mol–1) of the six- and seven-coordinate forms of both products were calculated as
follows: ∆ET = E(six) – E(seven) = ∆ESCF + ∆EZPE, in which ESCF is the SCF total energy and
EZPE is the zero point energy. The vibrational frequencies of the optimized geometries were
computed at the same level of calculation from analytic second derivatives and verified to be
real. They were used in support of our FTIR band assignments. Gas-phase thermodynamic
properties were evaluated at 298.15 K and 1.00 atm.
3. Results and discussion
3.1. Synthesis and preliminary characterization
Product (1) was prepared by salt metathesis from [(MeO2CCH2CH2)2SnCl2] and
NaMDTC, while (2) was synthesized by transesterification reaction of (1) with EtOH in the
presence of dmso (Scheme 1). Both diestertin(IV) compounds were obtained in moderate
yields as analytically pure colourless solids, as confirmed by satisfactory melting ranges and
elemental analyses.
Insert Scheme 1
5

The FTIR spectra of (1) and (2) exhibit two bands assigned to ν(CO), namely 1740
and 1709 cm-1 (1) and 1731 and 1694 cm-1 (2). The ν(CO) bands at lower wavenumbers
(1709 and 1694 cm-1) are ascribed to the semi-coordinated C=O groups of (1) and (2). These
values fall within the expected range for diestertin(IV) dithiocarbamate complexes [38]. In
the starting diestertin compound, [(MeO2CCH2CH2)2SnCl2], only one ν(CO) band is seen at
1677 cm-1. For both (1) and (2), vibrations related to the dithiocarbamate backbone occur in
the typical regions [38]. Moreover, each product exhibits two ν(Sn-C) bands in the range 600-
500 cm-1.
3.2. Multinuclear NMR
Insert Scheme 2
The NMR signals for (1) and (2) lie in the expected regions (Figures S1 and S2,
1
Appendix A) [38,69]. The H NMR signals for the ester groups of (1) and (2) are not too
3
different from those observed for [(MeO2CCH2CH2)2SnCl2]. The J(119/117Sn-1H) values [H5,
2
H5`: 113.6 (1) and 114.4 Hz (2)] are systematically greater than the corresponding J
parameters [H4, H4`: 92.9 (1) and 93.9 Hz (2)]. Stereo-electronic effects, such as geometry
and electronegativity of the ligands, might affect the magnitude of nJ(119/117Sn-1H).
Only one set of signals for the morpholine group was observed in the 13C NMR spectra
of (1) and (2). The signal for the NCS2 moiety observed at δ 202.1 stands out among the other
chemical shifts for the dithiocarbamate fragment [69]. Recently, we have detected two 13C
resonances for the carbonyl groups of [(EtO2CCH2CH2)2Sn(PDTC)2] and
[(BuO2CCH2CH2)2Sn(PDTC)2] (PDTC = pyrrolidinedithiocarbamate) assigned to free and
13
semi-coordinated C=O [38]. The morpholine analogues (1) and (2) display only one 13C
signal detected at δ 176 [2J(119/117Sn-13C), 126 (1) and 182 Hz (2)], as also observed for
[(MeO2CCH2CH2)2Sn(PDTC)2] and [(PrO2CCH2CH2)2Sn(PDTC)2] [38]. It is possible that an
1
exchange between hexa and heptacoordinated forms in solution averages the H and 13C
NMR signals, preventing detectable differences between the ester groups of (1) and (2). The
signals for C4 and C5, near δ 30, could not be distinguished from those observed for C4` and
1
13
C5` in the C NMR spectra of the products. The J(119Sn-13C) values for C4/C4`, 804.3 (1)
and 812.6 Hz (2), are larger than the respective constant for [(MeO2CCH2CH2)2SnCl2] (792
Hz).
In the 119Sn{1H} NMR spectra of (1) and (2), signals appear at δ -436.7 [1J(119Sn-13C)
3
= 804.3 Hz, J(119Sn-13C) = 130.3 Hz] and δ -443.2 [1J(119Sn-13C) = 812.6 Hz, 3J(119Sn-13C) =
6

123.1 Hz], respectively. In several studies reported in the literature the C-Sn-C angles (θ)
1
obtained from the J(119Sn-13C) coupling constants are compared with those values provided
by X-ray crystallography [70]. This information is valuable in determining similarities
between solution- and solid-state structures. In this work, the C-Sn-C angles (θ) in solution,
155.2o (1) and 156.0o (2), were evaluated using the following empirical equations:
|1J(119Sn-13C)| = 11.4 θ – 875 for Me-Sn-Me
|1J(119Sn-13C)| = [(9.99 0.73) θ – (746 100)] for Bu-Sn-Bu
|1J(119Sn-13C)| = [(15.56 0.84) θ – (1160 101)] for Ph-Sn-Ph
(1),
(2),
(3).
The average θ values obtained by single-crystal X-ray diffraction experiments (Section
3.3), 152.3o (1) and 151.98o (2), are close to the empirically calculated θ values in solution,
suggesting similar coordination geometries in solution and crystal states.
3.3. X-ray structure and Hirshfeld surfaces analyses
Both (1) and (2) crystallize in the monoclinic P21/n (No. 14) space group (Table I).
Their molecular structures in the crystal state are depicted in Figure 1. Selected bond lengths
and angles for (1) and (2) are listed in Table II. All bond distances display typical values
[71,72]. Also, the geometric parameters obtained for (1) resemble those observed for (2)
(Table II).
Insert Figure 1
Insert Table II
Our X-ray crystallographic results show that each product displays a seven-coordinate
metal centre in a distorted pentagonal bipyramidal coordination geometry (Figure 1 and Table
II). The same coordination geometry was observed for [(RO2CCH2CH2)2Sn(PDTC)2] (R =
Me, Et, Pr or Bu; PDTC = pyrrolidinodithiocarbamate) [38]. In 1 and 2, the apical positions
are occupied by similar Sn-C bonds. In addition, the C-Sn-C angles are smaller than 180o,
namely 152.28(9)o for (1) and 151.98(12)o for (2). The equatorial plane of each product
accommodates two bidentate morpholinodithiocarbamate ligands and one C=O···Sn
interaction. The morpholinodithiocarbamate ligands are unsymmetrically bound to tin. For
(1), the S1-Sn1, S2-Sn1, S3-Sn1 and S4-Sn1 distances amount to 2.6120(5), 2.8873(6),
2.5870(5) and 2.8655(6) Å, respectively. For (2), the respective distances are 2.5799(7),
7

2.9064(7), 2.5810(7) and 2.9179(7) Å. Furthermore, the intramolecular C=O···Sn contacts do
not considerably vary in length on going from (1) [O1···Sn1, 2.632 Å] to (2) [O1···Sn1,
2.618 Å] and are more than 1.0 Å shorter than the sum of O and Sn van der Waals radii, 3.70
Å [73]. The O1···Sn1 distances observed for (1) and (2) are also shorter than those obtained
for [(RO2CCH2CH2)2Sn(PDTC)2] [38].
Nonclassical hydrogen bonds for (1) and (2) are listed in Table III. They were
identified by Mercury [58] and PLATON [59] and confirmed by Hirshfeld surface analysis
[62-65]. In addition to intramolecular C-H···S contacts, the supramolecular architecture of
(1) comprises 1D zigzag chains along the [100] direction assembled by the C4-H4A···O3,
C4-H4B···O6, C4-H4C···O6, C16-H16B···S2, and C18-H18B···S4 interactions (Figure 2).
Adjacent chains are interconnected by the C2-H2A···O5 and C16-H16A···O5 contacts,
establishing 2D networks parallel to the ab plane. The C16-H16A···O5 contacts form 1D
zigzag chains along the [010] direction. In the supramolecular structure of (1), both O5 and
O6 are involved in bifurcated hydrogen-bonding schemes. Our results also show that C4 is an
excellent nonclassical hydrogen-bond donor.
Insert Table III
Insert Figure 2
According to Table III, the supramolecular arrangement of (2) does not involve any
ring-type motif but exhibits a robust C(8) C-H···S supramolecular synthon. In (2), the C1-
H1B···O3 and C9-H9B···S1 contacts form 1D chains along the diagonal of the [101]
direction, while the C4-H4B···O5 interactions establish 1D chains along the a axis. Together,
these contacts form 2D sheets parallel to the ac plane (Figure 3). Adjacent 2D networks are
assembled along the [010] direction by 1D zigzag chains formed by the C9-H9A···S3, C12-
H12A···O6 and C18-H18A···S1 interactions. In the crystal structure of (2), S1 is involved in
bifurcated hydrogen-bonding schemes.
Insert Figure 3
According to our Hirshfeld surface analysis (Figures S3 and S4, Appendix A),
isotropic van der Waals H···H contacts account for 58.2% of the Hirshfeld surface area for
(1), while H···O/O···H close contacts correspond to 21.0%. Besides, H···S/S···H contacts
contribute 14.5% to the Hirshfeld surface area for (1). The Hirshfeld surface analysis of (2)
has shown that dispersive H···H contacts respond for 63.3% of its Hirshfeld surface area,
8

whereas H···O/O···H and H···S/S···H close contacts contribute 18.0% and 14.0%,
respectively.
3.4. DFT Calculations
A DFT study of the six- and seven-coordinate forms of (1) and (2) has been carried out
at the B3LYP/LACV3P** level of calculation. The optimized geometries of these linkage
isomers are depicted in Figure 4. Their Cartesian coordinates are listed in Table S1
(Appendix A). The geometric parameters calculated for the seven-coordinate complexes
resemble those obtained by X-ray crystallography (Table S2, Appendix A). As expected,
Figure 4 shows that the hexacoordinated isomers exhibit a distorted octahedral geometry, and
the semi-coordinated C=O bond is slightly longer than the other C=O bond for the
heptacoordinated products. For (1), the seven-coordinate complex is 3.8 kcal mol-1 more
stable than the six-coordinate form. A similar energy difference (3.7 kcal mol-1) was found
for (2). These values provide an upper-bound estimate of the intramolecular C=O···Sn
interaction energy: -3.7 kcal mol-1. Moreover, the gas-phase enthalpy difference between the
six- and seven-coordinate isomers at 298.15 K amounts to 3.5 kcal mol-1 for (1) and 3.9 kcal
mol-1 for (2).
Insert Figure 4
4. Conclusions
Two diestertin(IV) morpholinodithiocarbamate complexes, (1) and (2), were
synthesized and characterized by vibrational (FTIR) and multinuclear (1H, 13C and 119Sn)
NMR spectroscopy and X-ray crystallography. According to our X-ray diffraction study, both
(1) and (2) display a distorted pentagonal bipyramidal coordination geometry since the apical
positions are occupied by ester groups and the equatorial plane accommodates two
(unsymmetrically bound) bidentate morpholinodithiocarbamate ligands and one
intramolecular C=O···Sn semi-coordination. Furthermore, our supramolecular analysis
revealed that the crystal packing of both products is governed by nonclassical C-H···O and
C-H···S hydrogen bonds. Finally, DFT calculations at the B3LYP/LACV3P** level provided
an upper-bound estimate of the C=O···Sn interaction energy, namely -3.7 kcal mol-1.
9

Appendix A. Supplementary data
CCDC 1533978 and 1533979 contain the supplementary crystallographic data for (1)
and (2), respectively. These data can be obtained free of charge via
http://www.ccdc.cam.ac.uk/conts/retrieving.html, or from the Cambridge Crystallographic
Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: (+44) 1223-336-033; or e-mail:
deposit@ccdc.cam.ac.uk. Supplementary figures and tables associated with this article can be
found in the online version.
Acknowledgements
The authors are grateful to the Brazilian funding agencies CNPq (306764/2013-0),
CAPES (5687-15-2), FAPEMIG (APQ 01832-14) and FAPERJ (E-26/201.338-2014) for
sponsorship.
10

References
[1] E. Frankland, Justus Liebigs Ann. Chem. 71 (1849) 171.
[2] E. Frankland, J. Chem. Soc. 2 (1850) 297.
[3] A.G. Davies, P.J. Smith, Tin, in: G.F. Wilkinson, F.G. Stone, E.W. Abel (Eds.),
Comprehensive Organometallic Chemistry, Pergamon Press, Oxford, 1982, vol. 2, pp.
523-527.
[4] M. Gielen, Coord. Chem. Rev. 151 (1996) 41.
[5] S.H.L. Thoonen, B.-J. Deelman, G. van Koten, J. Organomet. Chem. 689 (2004) 2145.
[6] A.C.A. Sousa, M.R. Pastorinho, S. Takahashi, S. Tanabe, Environ. Chem. Lett. 12
(2014) 117.
[7] R.E. Hutton, V. Oakes, Synthesis of Novel Substituted Alkyltin Halides, in: J.J.
Zuckerman (Ed.), Organotin Compounds: New Chemistry and Applications, American
Chemical Society, Washington DC, 1976, vol. 157, ch. 8, pp. 123-133.
[8] D. Lanigan, E.L. Weinberg, The Use of Estertin Stabilizers in PVC, in: J.J. Zuckerman
(Ed.), Organotin Compounds: New Chemistry and Applications, American Chemical
Society, Washington DC, 1976, vol. 157, ch. 9, pp. 134-154.
[9] A.H. Penninks, W. Seinen, Food Chem. Toxicol. 20 (1982) 909.
[10] R.E. Hutton, J.W. Burley, V. Oakes, J. Organomet. Chem. 156 (1978) 369.
[11] P.G. Harrison, T.J. King, M.A. Healy, J. Organomet. Chem. 182 (1979) 17.
[12] L. Tian, Z. Shang, Q. Yu, L. Zhang, Appl. Organomet. Chem. 19 (2005) 179.
[13] L. Tian, Q. Yu, Z. Shang, Y. Sun, L. Zhang, Appl. Organomet. Chem. 19 (2005) 677.
[14] L.-J. Tian, Y.-X. Sun, X.-J. Liu, G.-M. Yang, Z.-C. Shang, Polyhedron 24 (2005) 2027.
[15] G.M. de Lima, B.F. Milne, R.P. Pereira, A.M. Rocco, J.M.S. Skakle, A.J. Travis, J.L.
Wardell, S.M.S.V. Wardell, J. Mol. Struct. 921 (2009) 244.
[16] I. Omae, Appl. Organomet. Chem. 24 (2010) 374.
[17] L.-C. Zhang, S.-L. Zheng, H. Xue, Z.-M. Zhu, W.-S. You, Y.-G. Li, E. Wang, Dalton
Trans. 39 (2010) 3369.
[18] S.M. Kim, J.-H. Ju, O.-S. Jung, S.-H. Moon, K.-Y. Park, Bull. Korean Chem. Soc. 33
(2012) 2753.
[19] H. Yang, L.-C. Zhang, L. Yang, X.-L. Zhang, W.-S. You, Z.-M. Zhu, Inorg. Chem.
Commun. 29 (2013) 33.
[20] J.P. Eußner, S. Dehnen, Z. Anorg. Allg. Chem. 640 (2014) 295.
[21] Q. Liu, X. Shi, C. Zhang, L. Tian, Main Group Met. Chem. 38 (2015) 93.
11

[22] L.-P. Ji, J. Du, J.-S. Li, L.-C. Zhang, X.-J. Sang, H. Yang, H.-J. Cui, Z.-M. Zhu, RSC
Adv. 6 (2016) 28956.
[23] F. Fu, Z. Li, L. Tian, H. Pan, F. Kayser, R. Willem, M. Gielen, Bull. Soc. Chim. Belg.
101 (1992) 279.
[24] L. Tian, Z. Zhou, B. Zhao, Y. Su, C. Zhang, Main Group Met. Chem. 21 (1998) 735.
[25] L. Tian, Z. Zhou, B. Zhao, W. Yu, P. Yang, Synth. React. Inorg. Met.-Org. Chem. 30
(2000) 1363.
[26] L. Tian, B. Zhao, F. Li, Synth. React. Inorg. Met.-Org. Chem. 31 (2001) 139.
[27] L. Tian, Z. Zhou, Q. Yu, X. Liu, Synth. React. Inorg. Met.-Org. Chem. 33 (2003) 259.
[28] H.-S. Cheng, T.-L. Hwang, C.-S. Liu, J. Organomet. Chem. 254 (1983) 43.
[29] O.-S. Jung, J.H. Jeong, Y.S. Sohn, J. Organomet. Chem. 397 (1990) 17.
[30] R. Balasubramanian, Z.H. Chohan, S.M.S.V. Doidge-Harrison, R.A. Howie, J.L.
Wardell, Polyhedron 16 (1997) 4283.
[31] R.A. Howie, S.M.S.V. Wardell, Acta Crystallogr., Sect. E: Struct. Rep. Online 58
(2002) m257.
[32] Y. Dong, Acta Crystallogr., Sect. E: Struct. Rep. Online 63 (2007) m2917.
[33] G.M. de Lima, S.M.S.V. Wardell, J.L. Wardell, E.R.T. Tiekink, Acta Crystallogr., Sect.
E: Struct. Rep. Online 65 (2009) m1635.
[34] H. Buchanan, R.A. Howie, A. Khan, G.M. Spencer, J.L. Wardell, J.H. Aupers, J. Chem.
Soc., Dalton Trans. (1996) 541.
[35] S.W. Ng, C. Wei, V.G.K. Das, J.-P. Charland, F.E. Smith, J. Organomet. Chem. 364
(1989) 343.
[36] S.W. Ng, V.G.K. Das, Acta Crystallogr., Sect. C: Cryst. Struct. Commun. 51 (1995)
2492.
[37] V.G.K. Das, N.S. Weng, P.J. Smith, Inorg. Chim. Acta 49 (1981) 149.
[38] B.P. de Morais, C.L. Donnici, B.L. Rodrigues, G.M. de Lima, J.L. Wardell, R.S. Bitzer,
J. Organomet. Chem. 832 (2017) 57.
[39] C.S. Rocha, B.P. de Morais, B.L. Rodrigues, C.L. Donnici, G.M. de Lima, J.D.
Ardisson, J.A. Takahashi, R.S. Bitzer, Polyhedron 117 (2016) 35.
[40] L.C. Dias, G.M. de Lima, J.A. Takahashi, J.D. Ardisson, Appl. Organomet. Chem. 29
(2015) 305.
[41] B.P. de Morais, G.M. de Lima, C.B. Pinheiro, R.A. Burrow, D.F. Back, R.A.S. San Gil,
D.C. Menezes, J.D. Ardisson, Polyhedron 102 (2015) 344.
[42] B.P. de Morais, G.M. de Lima, C.B. Pinheiro, R.A.S. San Gil, J.A. Takahashi, D.C.
Menezes, J.D. Ardisson, J. Mol. Struct. 1094 (2015) 246.
12

[43] I.P. Ferreira, G.M. de Lima, E.B. Paniago, W.R. Rocha, J.A. Takahashi, C.B. Pinheiro,
J.D. Ardisson, Polyhedron 79 (2014) 161.
[44] I.P. Ferreira, G.M. de Lima, E.B. Paniago, W.R. Rocha, J.A. Takahashi, C.B. Pinheiro,
J.D. Ardisson, Eur. J. Med. Chem. 58 (2012) 493.
[45] L.C. Dias, M.M.M. Rubinger, J.P. Barolli, J.D. Ardisson, I.C. Mendes, G.M. de Lima,
L. Zambolim, M.R.L. Oliveira, Polyhedron 47 (2012) 30.
[46] F.T. Vieira, D.C. Menezes, G.M. de Lima, J.L. Wardell, M.E. Cortés, G.A.B. Silva, A.
Vilas-Boas, J.R.S. Maia, Appl. Organomet. Chem. 22 (2008) 433.
[47] D.C. Menezes, F.T. Vieira, G.M. de Lima, J.L. Wardell, M.E. Cortés, M.P. Ferreira,
M.A. Soares, A.V. Boas, Appl. Organomet. Chem. 22 (2008) 221.
[48] D.C. Menezes, G.M. de Lima, G.S. de Oliveira, A.V. Boas, A.M.A. Nascimento, F.T.
Vieira, Main Group Met. Chem. 31 (2008) 21.
[49] D.C. Menezes, G.M. de Lima, A.O. Porto, M.P. Ferreira, J.D. Ardisson, R.A. Silva,
Main Group Met. Chem. 30 (2007) 49.
[50] C.S. Rocha, B.P. de Morais, B.L. Rodrigues, C.L. Donnici, G.M. de Lima, J.D.
Ardisson, J.A. Takahashi, R.S. Bitzer, Appl. Organomet. Chem. doi: 10.1002/aoc.3645.
[51] S.W. Ng, C. Wei, V.G.K. Das, G.B. Jameson, R.J. Butcher, J. Organomet. Chem. 365
(1989) 75.
[52] O.-S. Jung, J.H. Jeong, Y.S. Sohn, Organometallics 10 (1991) 2217.
[53] S.W. Ng, Acta Crystallogr., Sect. C: Cryst. Struct. Commun. 49 (1993) 753.
[54] Agilent, CrysAlisPro, Agilent Technologies Ltd, Yarnton, Oxfordshire, England, 2014.
[55] G.M. Sheldrick, Acta Crystallogr., Sect. A: Found. Crystallogr. 64 (2008) 112.
[56] G.M. Sheldrick, Acta Crystallogr. Sect. C. Struct. Chem. 71 (2015) 3.
[57] L.J. Farrugia, J. Appl. Crystallogr. 45 (2012) 849.
[58] C.F. Macrae, P.R. Edgington, P. McCabe, E. Pidcock, G.P. Shields, R. Taylor, M.
Towler, J. van de Streek, J. Appl. Crystallogr. 39 (2006) 453.
[59] (a) A.L. Spek, J. Appl. Crystallogr. 36 (2003) 7; (b) A.L. Spek, Acta Crystallogr. Sect.
D. Biol. Crystallogr. 65 (2009) 148.
[60] F.H. Allen, O. Johnson, G.P. Shields, B.R. Smith, M. Towler, J. Appl. Crystallogr. 37
(2004) 335.
[61] R.H. Blessing, Acta Crystallogr., Sect. A: Found. Crystallogr. 51 (1995) 33.
[62] M.A. Spackman, J.J. McKinnon, CrystEngComm 4 (2002) 378.
[63] J.J. McKinnon, M.A. Spackman, A.S. Mitchell, Acta Crystallogr. Sect. B Struct. Sci. 60
(2004) 627.
[64] J.J. McKinnon, D. Jayatilaka, M.A. Spackman, Chem. Commun. (2007) 3814.
13

[65] M.A. Spackman, D. Jayatilaka, CrystEngComm 11 (2009) 19.
[66] S.K. Wolff, D.J. Grimwood, J.J. McKinnon, M.J. Turner, D. Jayatilaka, M.A.
Spackman, CrystalExplorer (Version 3.1), University of Western Australia, 2012.
[67] JAGUAR (Version 7.9), Schrödinger, LLC, New York, NY (2011).
[68] A.D. Becke, J. Chem. Phys. 98 (1993) 5648.
[69](a) D. Dakternieks, H. Zhu, D. Masi, C. Mealli, Inorg. Chem. 31 (1992) 3601; (b) A.N.
Gupta, V. Kumar, V. Singh, A. Rajput, L.B. Prasad, M.G.B. Drew, N. Singh, J.
Organomet. Chem. 787 (2015) 65.
[70] (a) J. Holecek, M. Nadvornik, K. Handlir, A. Lycka, J. Organomet. Chem. 1986, 315,
299. (b) T. P. Lockhart, W. F. Manders, J. J. Zuckerman, J. Am. Chem. Soc. 1985, 107,
4546. (c) T. P. Lockhart, W. F. Manders, J. Am. Chem. Soc. 1987, 109, 7015.
[71] F.H. Allen, O. Kennard, D.G. Watson, L. Brammer, A.G. Orpen, R. Taylor, J. Chem.
Soc., Perkin Trans. 2 (1987) S1.
[72] A.G. Orpen, L. Brammer, F.H. Allen, O. Kennard, D.G. Watson, R. Taylor, J. Chem.
Soc., Dalton Trans. (1989) S1.
[73] A. Bondi, J. Phys. Chem. 68 (1964) 441.
[74] (a) M.C. Etter, Acc. Chem. Res. 23 (1990) 120; (b) M.C. Etter, J.C. MacDonald, J.
Bernstein, Acta Crystallogr., Sect. B: Struct. Sci. 46 (1990) 256.
14

Captions for Schemes, Figures and Tables
Table I. Crystal data and structure refinement parameters for [(RO2CCH2CH2)2Sn(MDTC)2]
(R = Me (1) or Et (2); MDTC = morpholinodithiocarbamate).
Table II. Selected bond lengths (Å) and angles (o) for (1) and (2).
Table III. Noncovalent interactions and supramolecular motifs for (1) and (2).a
Scheme 1. Preparation of [(RO2CCH2CH2)2Sn(MDTC)2] (R = Me (1) or Et (2); MDTC =
morpholinodithiocarbamate).
Scheme 2. Atom numbering scheme for 1H and 13C{1H} NMR assignments.
Figure 1. Atom numbering schemes and molecular structures of complexes (1) (left) and (2)
(right) in the crystal state. Ellipsoids are drawn at the 50% probability level and
hydrogen atoms are omitted for clarity.
Figure 2. Packing diagram of (1) highlighting a 1D zigzag chain along the [100] direction. H
atoms except those involved in hydrogen bonds are omitted for clarity. Symmetry
codes: (ii) -x,-y,2-z; (iii) -1+x,y,z; (iv) 1-x,-y,2-z; (vi) 1+x,y,z.
Figure 3. Packing diagram of (2) showing a 2D network parallel to the [101] plane. H atoms
except those involved in hydrogen bonds are omitted for clarity. Symmetry codes:
(vi) 1+x,y,z; (vii) -0.5+x,0.5-y; (ix) 0.5+x,0.5-y,0.5+z.
Figure 4. DFT-optimized geometries of the six- (left) and seven-coordinate (right) isomers of
(1) (top) and (2) (bottom). H atoms are omitted for clarity. Bond distances are given in
Å.
15

Table I
(1)
(2)
Crystal description
Empirical formula
M/g mol–1
Colourless prism
C18H30N2O6S4Sn
617.37
Colourless prism
C20H34N2O6S4Sn
645.42
T/K
150(1)
150(1)
0.71073 (Mo-Kα)
Monoclinic
P21/n (No. 14)
11.2490(2)
17.1944(2)
13.0525(2)
99.606(2)
2489.21(7)
4
0.71073 (Mo-Kα)
Monoclinic
P21/n (No. 14)
12.8474(5)
16.1777(6)
13.6492(6)
106.594(4)
2718.7(2)
4
λ/Å
Crystal system
Space group
a/Å
b/Å
c/Å
β/o
V/Å3
Z
Dx/Mg m–3
1.647
1.577
µ/mm–1
1.398
1.283
F(000)
1256
1320
Crystal size/mm3
θ range/o
0.1 x 0.1 x 0.1
1.98 to 29.48
0.1 x 0.1 x 0.1
1.92 to 29.56
Index ranges
–15 ≤ h ≤ 15
–22 ≤ k ≤ 22
–16 ≤ l ≤ 17
57968
–17 ≤ h ≤ 16
–21 ≤ k ≤ 16
–18 ≤ l ≤ 17
13920
Reflections collected
Independent reflections
Observed reflections
6520
6513
5637 [I > 2σ(I)]
100%
5178 [I > 2σ(I)]
100%
Completeness to θmax
Absorption correction
Tmax and Tmin
Multi-scan [61]
1.0000 and 0.7984
Full-matrix least-squares on F2
6520 / 0 / 280
Multi-scan [61]
1.0000 and 0.7233
Full-matrix least-squares on F2
6513 / 0 / 298
Refinement method
Data / restraints / parameters
Goodness-of-fit on F2
Final R indices [I > 2σ(I)]a
R indices (all data)a
1.044
1.093
R1 = 0.0255, wR2 = 0.0550
R1 = 0.0334, wR2 = 0.0594
1.004 and -0.449
CCDC 1533978
R1 = 0.0301, wR2 = 0.0686
R1 = 0.0479, wR2 = 0.0846
0.688 and -0.658
∆ρmax and ∆ρmin/e Å–3
Deposition number
CCDC 1533979
½
a R1 = (Σhkl ||Fo| – |Fc||)/(Σhkl |Fo|) and wR2 = {[Σhkl w(Fo2 – Fc2)2]/[Σhkl w(Fo2)2]} .
16

Table II.
(1)
C1-Sn1-C5 152.28(9)
(2)
C1-Sn1 2.134(2)
C5-Sn1 2.138(2)
S1-Sn1 2.6120(5)
S2-Sn1 2.8873(6)
S3-Sn1 2.5870(5)
S4-Sn1 2.8655(6)
O1-Sn1 2.632 (2)
C9-S1 1.732(2)
C9-S2 1.702(2)
C14-S3 1.737(2)
C14-S4 1.705(2)
C9-N1 1.336(3)
C14-N2 1.329(3)
C3-O1 1.201(2)
C3-O2 1.327(3)
C7-O3 1.203(3)
C7-O4 1.331(3)
C1-Sn1 2.134(3)
C6-Sn1 2.138(2)
S2-C11-S1 118.58(15)
S4-C16-S3 118.32(15)
S1-Sn1-S2 64.690(15)
S3-Sn1-S4 65.370(15)
O1-Sn1-S2 76.34(4)
O1-Sn1-S4 74.08(4)
S2-C9-S1 118.48(12)
S4-C14-S3 118.23(12)
S1-Sn1 2.5799(7) C1-Sn1-C6 151.98(12)
S2-Sn1 2.9064(7) S3-Sn1-S4 64.46(2)
S1-Sn1-S2 64.83(2)
S4-Sn1 2.9179(7) O1-Sn1-S2 79.78(5)
S3-Sn1 2.5810(7)
O1-Sn1 2.618(2)
C11-S1 1.729(3)
C11-S2 1.707(3)
C16-S3 1.739(3)
C16-S4 1.693(3)
C16-N2 1.338(3)
C11-N1 1.336(3)
C8-O3 1.200(3)
C8-O4 1.343(3)
C3-O1 1.215(3)
C3-O2 1.323(4)
O1-Sn1-S4 73.43(5)
17

Table III.
Type
Geometric parameters
Motifb
Ga (r)
D–H···A
D–H/Å
H···A/Å
D···A/Å
D–H···A/o
d
(1)
C2-H2A···O5i
C4-H4A···O3ii
C4-H4B···O6iii
C4-H4C···O6iv
C10-H10B···S1
C12-H12A···S2
C15-H15B···S3
C16-H16A···O5v
C16-H16B···S2vi
C17-H17A···S4
0.97
0.96
0.96
0.96
0.97
0.97
0.97
0.97
0.97
0.97
0.97
2.65
2.63
2.54
2.50
2.54
2.52
2.53
2.52
2.77
2.52
2.96
3.450(3)
3.487(3)
3.377(3)
3.432(3)
3.040(2)
3.034(2)
3.052(2)
3.468(3)
3.609(2)
3.042(2)
3.466(2)
139.6
148.3
145.7
163.7
111.9
113.3
113.6
165.1
145.3
113.5
113.8
R2 (20)
2
R2 (20)
2
C(12)
R2 (24)
2
S(5)
S(5)
S(5)
C(13)
C(8)
S(5)
C18-H18B···S4iv
R2 (12)
2
(2)
C1-H1B···O3vii
0.97
0.97
0.96
0.97
0.97
0.97
0.97
0.97
0.97
0.97
0.97
2.66
2.42
2.62
2.95
3.02
2.41
2.50
2.56
2.50
3.02
2.56
3.593
162.4
151.8
112.4
129.4
134.3
152.1
111.3
110.4
113.2
152.3
113.4
C(7)
C(12)
S(6)
C4-H4B···O5vi
C5-H5C···O1
3.308(4)
3.115(5)
3.647(3)
3.763(3)
3.301(4)
2.994(3)
3.038(3)
3.017(3)
3.907(3)
3.076(3)
C9-H9A···S3viii
C9-H9B···S1ix
C12-H12A···O6viii
C12-H12B···S1
C14-H14A···S2
C17-H17A···S3
C18-H18A···S1x
C19-H19B···S4
C(8)
C(8)
C(12)
S(5)
S(5)
S(5)
C(8)
S(5)
a
Symmetry codes: (i) -x,1-y,2-z; (ii) -x,-y,2-z; (iii) -1+x,y,z; (iv) 1-x,-y,2-z; (v) 0.5-x,-0.5+y,1.5-z; (vi) 1+x,y,z; (vii) -0.5+x,0.5-y,-0.5+z;
(viii) 0.5-x,0.5+y,2.5-z; (ix) 0.5+x,0.5-y,0.5+z; (x) 0.5-x,-0.5+y,2.5-z.
b Etter’s graph-set assignment [74].
18

Scheme 1
Scheme 2
19

Figure 1
20

Figure 2
21

Figure 3
22

Figure 4
23

The diestertin(IV) dithiocarbamate complexes [(RO2CCH2CH2)2Sn(MDTC)2] (R = Me (1) or Et (2);
MDTC = morpholinodithiocarbamate) have been prepared, characterized and structurally authenticated.
Complex (1) has been obtained from the reaction of [(MeO2CCH2CH2)2SnCl2] with sodium
morpholinodithiocarbamate (NaMDTC) in CHCl3, and its transesterification reaction with EtOH in the
presence of dmso yielded complex (2).
24

(1)
(2)
25