Xian-He
Bu
*,
Wei
Chen
,
Miao
Du
and
Ruo-Hua
Zhang
Department of Chemistry, Nankai University, Tianjin, 300071, P. R. China. E-mail: buxh@nankai.edu.cn
The first AgI complex with a flexible meso-bis(sulfinyl) ligand forming a unique two-dimensional, 36-membered macrometallacyclic molecular square array is reported.
Herein is reported the first AgI complex with a flexible meso-bis(sulfinyl) ligand (L) forming a unique macrometallacyclic lamellar network.
The underlying principle of this study design is as follows. Bis(sulfinyl) compounds have advantages that: (a) they are bifunctional ligands in terms that both S and O atoms are potential donor atoms and they have ditopic coordination sites which may allow structures with higher dimensions; (b) each S atom with a pyramidal geometry is an asymmetric center which may introduce acentric sites into the resulting crystals [for example, if ligands with an RS configuration were used (as in this study), the resulting network as a whole would be mesomeric; however, if ligands with RR or SS configurations were used, one would expect to obtain chiral networks with acentric cavities]; (c) such structurally flexible ligands have the possibility of forming diverse extended networks which might be deeply influenced and controlled by the length of the spacer unit and the template anions; and (d) the bis(sulfinyl) ligands having ditopic donor sites (S and O), of which the chemistry is still less developed, are likely to be widely relevant in the context of a vast variety of metal moieties and may be expected to develop into a rich coordination chemistry.
Caution! While we experienced no problems in handling perchlorates in this study, these should be handled with great care due to the potential for explosion.
Parameter | 1 |
---|---|
a Click b105297g.txt for full crystallographic data (CCDC 164457). | |
Formula | Ag(C16H18O2S2)2ClO4 |
Crystal dimensions/mm | 0.35⊕×⊕0.35⊕×⊕0.40 |
M | 820.17 |
Crystal system | Tetragonal |
Space group | P4/ncc |
a/Å | 15.189(2) |
b/Å | 15.189(2) |
c/Å | 15.191(3) |
V/Å3 | 3504.7(10) |
Z | 4 |
T/K | 293⊕±⊕2 |
D c/g cm−3 | 1.554 |
μ/mm−1 | 0.938 |
F(000) | 1680 |
Measured reflections | 13321 |
Unique reflections | 1560 |
R (Rint) | 0.0317 (0.0566) |
R w | 0.0824 |
Goodness of fit on F2 | 1.001 |
Largest difference, peak and hole/e Å−3 | 0.479, −0.264 |
As shown in Fig. 1, the AgI centers of 1 are coordinated by four oxygen atoms of the sulfoxide moieties of four distinct L ligands and form a perfect square-planar coordination geometry, with all four Ag–O bonds being equivalent [2.318(2) Å] and the adjacent O–Ag–O angles being almost 90° [89.985(2)°] (Table 2).
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Fig. 1 ORTEP view of the coordination geometry around each AgI center of complex 1. Click image or 1.htm to access a 3D representation. |
Ag(1)–O(1) | 2.318(2) | S(1)–O(1) | 1.503(2) |
O(1A)–Ag(1)–O(1C) | 179.17(11) | O(1A)–Ag(1)–O(1) | 89.985(2) |
S(1)–O(1)–Ag(1) | 119.67(12) | O(1)–S(1)–C(11) | 107.98(13) |
C(11)–S(1)–C(1) | 96.29(13) |
This is a very rare example of the coordination geometry of AgI.8 Normally, S atoms have a higher affinity than O atoms with the soft AgI ions.9 However, in complex 1 it is the O atoms, and not the S atoms, of the ditopic ligands that coordinate to the AgI ions, probably due to the steric hindrance of the bulky phenyl groups connected to the S atoms.7 Two of the four sulfur atoms bound to the oxygens are R- whereas the other two have the S-configuration. Therefore, the network of 1 as a whole is mesomeric but with local acentric sites in the cavities. The adjacent AgI centers are linked viaL in orthogonal directions, which results in a molecular domain constituted by a highly symmetrical 36-membered Ag4L4 macrocycle with the adjacent Ag–Ag distances of 11.177 Å. Two AgI corners in the diagonal position fold toward the upside or downside to form a ‘valley-like’ molecular unit, which has S4 symmetry (Fig. 2). The perchlorate ions filling in the cavity of the ‘valley’ [side view of the network, Fig. 3(b)] may act as templates for the formation of the network and consequently keep the structure stable [Fig. 2(b)]. Adjacent rings are fused in a unique two-dimensional lamellar structure [Fig. 3(a), the top view of the network of 1, a (4,4) net].
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Fig. 2 (a) The basket-like 36-membered Ag4L4 repeating unit with S4 symmetry of 1. Ag(1)–O(1) 2.318(2) Å, O(1A)–Ag(1)–O(1B) 89.985(2)°. (b) Space-filling diagram showing the accommodation of a perchlorate anion in the basket-like repeating unit from the top view. Ag purple; S yellow; Cl green; O red; C grey. |
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Fig. 3 (a) View from the c axis showing the two-dimensional square-grid of 1. Hydrogen atoms are omitted for clarity. (b) View of the wave-like layer stacking of 1 in the c direction including the perchlorate anions. |
To the best of our knowledge, complex 1 is the first structurally characterized AgI complex with a flexible bis(sulfinyl) ligand, in which each AgI center takes a rare, perfect, square coordination geometry, and where the network as a whole is mesomeric because L has RS configuration. The ‘valley’ sheet of 1 is a unique structural motif.
In conclusion, a novel AgI complex forming unique macrometallacyclic lamellar networks has been reported. A systematic study on bis(sulfinyl) ligands by varying the spacer units of their backbone, and further studies using bis(sulfinyl) ligands with SS or RR configurations for the construction of chiral networks, are currently underway in our laboratory.
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