Bis(μ-iodo)-tetrakis(O-methyl N-phenylthiocarbamate)- tetraiodo-dibismuth

In order to investigate the coordination chemistry of O-alkyl N-aryl thiocarbamate ligands, BiI3 was reacted with two equivalents of MeOC(=S)N(H)Ph in MeCN solution to afford the dinuclear title compound complexes [{I2Bi(μ2-I)2BiI2}{κ-MeOC(=S)N(H)Ph}4] 1. Compound 1 was characterized by IR, UV and NMR spectroscopy, the formation of a dinuclear framework is ascertained by a single-crystal X-ray diffraction study performed at 100 K.


Introduction
Thiocarbamates, also called thiocarbamides of general formula ROC(=S)N(H)R', play not only a role in organic chemistry as building blocks for further transformations, but found also application in various domains such biological and pharmacological activity or catalysis [1][2][3][4][5]. Furthermore, they have attracted the attention of coordination chemists, since the soft C=S thione function (according Pearson's HSAB principle) [6] readily coordinates to a wide range of transition metal complexes giving complexes with Cu(I), Ag(I), Au(I), Pd(II), Rh(III), etc. Some crystallographically characterized complexes ligated by O-alkyl N-aryl and O-alkyl N-alkyl thiocarbamates are presented in Scheme 1 [7][8][9].

Introduction
Thiocarbamates, also called thiocarbamides of general formula ROC(=S)N(H)R', play not only a role in organic chemistry as building blocks for further transformations, but found also application in various domains such biological and pharmacological activity or catalysis [1][2][3][4][5]. Furthermore, they have attracted the attention of coordination chemists, since the soft C=S thione function (according Pearson's HSAB principle) [6] readily coordinates to a wide range of transition metal complexes giving complexes with Cu(I), Ag(I), Au(I), Pd(II), Rh(III), etc. Some crystallographically characterized complexes ligated by O-alkyl N-aryl and O-alkyl N-alkyl thiocarbamates are presented in Scheme 1 [7][8][9]. Surprisingly, despite the growing number of transition metal complexes bearing such type of thione ligands, there is a lack of p block metal complexes coordinated with O-alkyl N-aryl thiocarbamates. Since BiX3 complexes with thione-type ligand are literature-known (see below) and may even display a biological activity [10][11][12]   Surprisingly, despite the growing number of transition metal complexes bearing such type of thione ligands, there is a lack of p block metal complexes coordinated with O-alkyl N-aryl thiocarbamates. Since BiX 3 complexes with thione-type ligand are literatureknown (see below) and may even display a biological activity [10][11][12], we reacted BiI 3 with O-methyl N-phenyl thiocarbamate and describe therein the crystal structure of the isolated the isolated complex. This research is a continuation of our investigations on th nation chemistry of thione-type ligand on diverse metal centers [13][14][15][16].

Results
The hitherto unknown complex [{I2Bi(μ2-I)2BiI2}{κ 1 -MeOC(=S)N(H)Ph}4] 1 tained by addition of two equivalents of O-methyl N-phenyl thiocarbamate L to sion of BiI3 in MeCN (Scheme 2). After stirring for 3 h followed by short heating a deep orange solution formed. Slow evaporation of the solvent yielded dark-o stable crystals, whose IR-ATR spectrum confirmed the complexation of L on B cording to the elemental analysis, two L molecules are attached per BiI3 motif. The 1 H-NMR recorded in d6-actetone reveals a broad hump at δ 4.04 for the group, whereas the aryl signals are well resolved. Furthermore, two distinct N nances are found at δ 9.32 and 10.03. A further indication of dynamic processes in solution is provided by the 1 H NMR spectrum of 1 recorded at 323 K, in which resonance at δ 4.05 is considerably sharpened (Figure 1). There is also a noticea field shift of the N-H signals. This dynamic behavior has not been investigated detail. Since according to a literature survey, no Bi(III) complexes ligated by thioca have been crystallographically characterized yet, we examined the product cry in the triclinic space group P1 by an X-ray diffraction study performed at 100 K. A in Figure 2, a dinuclear species has formed, in which the two crystallographically coordinated Bi(III) centers are linked mutually through two μ2-bridging I3 and The 1 H-NMR recorded in d 6 -actetone reveals a broad hump at δ 4.04 for the methoxy group, whereas the aryl signals are well resolved. Furthermore, two distinct N-H resonances are found at δ 9.32 and 10.03. A further indication of dynamic processes occurring in solution is provided by the 1 H NMR spectrum of 1 recorded at 323 K, in which the OMe resonance at δ 4.05 is considerably sharpened (Figure 1). There is also a noticeable high-field shift of the N-H signals. This dynamic behavior has not been investigated in more detail.
the isolated complex. This research is a continuation of our investigations on the coo nation chemistry of thione-type ligand on diverse metal centers [13][14][15][16].

Results
The hitherto unknown complex [{I2Bi(μ2-I)2BiI2}{κ 1 -MeOC(=S)N(H)Ph}4] 1 was tained by addition of two equivalents of O-methyl N-phenyl thiocarbamate L to a susp sion of BiI3 in MeCN (Scheme 2). After stirring for 3 h followed by short heating to 60 a deep orange solution formed. Slow evaporation of the solvent yielded dark-orange stable crystals, whose IR-ATR spectrum confirmed the complexation of L on Bi(III). cording to the elemental analysis, two L molecules are attached per BiI3 motif. The 1 H-NMR recorded in d6-actetone reveals a broad hump at δ 4.04 for the meth group, whereas the aryl signals are well resolved. Furthermore, two distinct N-H re nances are found at δ 9.32 and 10.03. A further indication of dynamic processes occurr in solution is provided by the 1 H NMR spectrum of 1 recorded at 323 K, in which the O resonance at δ 4.05 is considerably sharpened (Figure 1). There is also a noticeable hi field shift of the N-H signals. This dynamic behavior has not been investigated in m detail. Since according to a literature survey, no Bi(III) complexes ligated by thiocarbama have been crystallographically characterized yet, we examined the product crystalliz in the triclinic space group P1 by an X-ray diffraction study performed at 100 K. As sho in Figure 2, a dinuclear species has formed, in which the two crystallographically differ coordinated Bi(III) centers are linked mutually through two μ2-bridging I3 and I4 iod ligands. The Bi···Bi separation of 4.720 Å excludes any intermetallic interaction. The o hedral coordination sphere around each Bi atom is completed by two terminal iodide ands with a mean Bi-Iterm distance of 2.924(3) Å and two trans-arranged thiocarbam Since according to a literature survey, no Bi(III) complexes ligated by thiocarbamates have been crystallographically characterized yet, we examined the product crystallizing in the triclinic space group P1 by an X-ray diffraction study performed at 100 K. As shown in Figure 2, a dinuclear species has formed, in which the two crystallographically different coordinated Bi(III) centers are linked mutually through two µ 2 -bridging I3 and I4 iodido ligands. The Bi···Bi separation of 4.720 Å excludes any intermetallic interaction. The octahedral coordination sphere around each Bi atom is completed by two terminal iodide ligands with a mean Bi-I term distance of 2.924(3) Å and two trans-arranged thiocarbamate ligands. Each of the four L molecules is crystallographically different with Bi-S bond lengths varying from 2.8290(10) to 2.8952(11) Å. The mean C=S bond is slightly elongated with respect to that of non-ligated MeOC(=S)N(H)Ph (1.701(4) vs. 1.6708(11) Å) [17]. The two bridging I2 and I4 atoms are quite symmetrically bridging, the mean Bi-I bridg bond distance of 3.225(3) Å being far longer than the Bi-I term one.  In the packing, several secondary weak interactions are present such as betw oms I1 i -H22 (3.081 Å), C14 i -H24A (2.757 Å), H5-H8B i (2.293 Å) and I3 i -H29 (3 Furthermore, as shown in Figure 3, loose intramolecular S···H and N···H contacts In the packing, several secondary weak interactions are present such as between atoms I1 i -H22 (3.081 Å), C14 i -H24A (2.757 Å), H5-H8B i (2.293 Å) and I3 i -H29 (3.128 Å). Furthermore, as shown in Figure 3, loose intramolecular S···H and N···H contacts occur.
These interactions have also been assessed by means of a Hirshfeld surface analysis using the CrystalExplorer17 software ( Figure 4) [18,19]. The Hirshfeld surface was mapped over d norm in the range from -0.0743 to -1.2577 (arbitrary units). The corresponding fingerprints plots are presented in the Supporting Material. These interactions have also been assessed by means of a Hirshfeld surface analysis using the CrystalExplorer17 software ( Figure 4) [18,19]. The Hirshfeld surface was mapped over dnorm in the range from -0.0743 to -1.2577 (arbitrary units). The corresponding fingerprints plots are presented in the Supporting Material.

Experimental
To a slurry of BiI 3 (294.8 mg, 0.5 mmol) in 10 mL of acetonitrile, O-methyl N-phenylthiocarbamate L (167.2 mg, 1 mmol) was added in several portions. The reaction was first stirred at room temperature for 3h, and then heated to 60 • C for 10 min. After reaching ambient temperature, the solvent was allowed to evaporate partially. After 2 days, dark orange crystals of 1 were formed and then collected by filtration. Yield: 79%. (Supplementary Materials). The data can be obtained free of charge from the Cambridge Crystallographic Data Centre via http://www.ccdc.cam.ac.uk/getstructures. The structure was solved by direct methods and refined by full-matrix least-squares against F 2 (SHELXL,2015 [21,22]).

Conclusions
We have crystallographically evidenced that not only transition metals, but also p-block salts such as BiI 3 , can constitute interesting targets for the coordination of thiocarbamate ligands via their thione function.
Supplementary Materials: The following supporting information can be downloaded, CIF file, Check-CIF report, UV-Vis spectrum and Hirshfeld fingerprint plot.
Author Contributions: W.A. prepared the compound; C.S. and A.S. collected the X-ray data and solved the structure; A.K. and M.K. designed the study and analyzed the data and M.K. wrote the paper. All authors have read and agreed to the published version of the manuscript.
Funding: This research received no external funding.
Data Availability Statement: The X-ray data are at CCDC as stated in the paper.