Chalcogen Bonds in Crystals of Bis(o-anilinium)diselenide Salts

Subscriber access provided by University of Winnipeg Library

Article

Chalcogen Bonds in Crystals of Bis(o-anilinium)diselenide Salts Patrick Scilabra, Jane Murray, Giancarlo Terraneo, and Giuseppe Resnati Cryst. Growth Des., Just Accepted Manuscript • DOI: 10.1021/acs.cgd.8b01634 • Publication Date (Web): 18 Dec 2018 Downloaded from http://pubs.acs.org on December 22, 2018

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 14 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Crystal Growth & Design

Chalcogen Bonds in Crystals of Bis(o-anilinium)diselenide Salts Patrick Scilabra,† Jane S. Murray,‡ Giancarlo Terraneo,† Giuseppe Resnati†* †

Department of Chemistry, Materials, and Chemical Engineering “Giulio Natta”, Politecnico di Milano, via Mancinelli 7, 20131 Milano, Italy ‡ Department of Chemistry, University of New Orleans, New Orleans, LA70148, USA. S

Supporting Information

ABSTRACT: The diselenide moiety is labelled as a novel and robust chalcogen bond (ChB) donor group. The molecular electrostatic potential of two prototype diselenide derivatives show the presence of two -holes along both the covalent bonds in which each selenium atom is involved. The propensity of selenium atoms of diselenides to work as electrophilic sites is confirmed by computational studies on bis(o-anilinium)diselenide cation and single crystals x-ray analysis of salts of this cation reveal the presence of close selenium∙∙∙anion contacts. Comparison with halogen bonds in crystal structures of ionic λ3-iodane derivatives supports the rationalization of these close contacts as charge assisted ChBs. Discrete adducts or two dimensional networks are formed, suggesting the profitable use of the diselenide moiety in ChB based crystal engineering.

1. INTRODUCTION The hydrogen bond (HB), the attractive interaction wherein hydrogen atoms are the electrophilic site, was first recognized more than one hundred years ago.1 In more recent times it was acknowledged that atoms of many elements besides hydrogen can function as electrophiles and form attractive interactions with sites of high electron density. Twenty years ago the halogen bond (XB),2,3 the interaction between atoms of group 17 elements and lone pair possessing atoms, anions, and -bonds, was recognized as a new paradigm in supramolecular chemistry and is now effectively used in numerous and different fields.4 During the last years it was realized that also elements of groups 16, 15, or 14 of the Periodic Table can behave similarly, namely they can act as effective electrophilic sites when interacting with electron rich atoms/moieties and thus give rise to the so named chalcogen,5 pnictogen,6 or tetrel bonds,7 respectively (ChB, PnB, or TtB, respectively). The formation of all the interactions mentioned above, HB included, is associated with the anisotropic distribution of the electron density in covalently bonded atoms.8 In fact, region(s) of depleted electron density, the so named holes,9 are typically present along the extension(s) of the covalent bond(s) formed by atoms of groups 14-17 of the Periodic Table. These -holes frequently present positive electrostatic potential, electron rich sites (Lewis bases) attractively interact with these positive -holes, and the above mentioned interactions are formed.10–12 The positive potential at some regions of bonded atoms reflects not only the lower electronic density on the side of the atom opposite to the bond, along its extension, but also contributions from other portions of the molecule. These can significantly influence both the value and the angular position of the region of most positive potential, causing it to deviate from

the extension of the covalent bond,8 particularly for atoms of groups 15 and 16. In this paper we report a combined computational and experimental study on diaryldiselenides 1a-c (Scheme 1) and related prototype diselenides 2 and 3. Modelling shows that -holes with positive electrostatic potential are present on selenium atoms in all studied systems and single crystal Xray analyses reveals that close13 and linear intermolecular interactions at selenium are particularly influential for the packing adopted by the compounds in the solid. Electrostatic cation–anion attraction largely accounts for the close contacts around selenium atoms in 1a-c salts, but anions preferentially enter along the extension of covalent bonds formed by selenium and the calculated molecular electrostatic potentials of diselenide dication of 1a-c and model compounds 2 and 3 show the presence of -holes on the extension of covalent bonds at selenium so that the close cation-anion contacts in 1a-c can be considered charge assisted ChBs. These ChBs are significantly shorter than the sum of van der Waals radii of involved atoms suggesting that selenium atoms in conveniently engineered organic diselenides can be reliable ChB donors, namely acceptors of electron density, and determine the packing in crystalline solids.

2+ NH3

Se Se H3N

2X

-

X 1a

4-CH3-C6H4-SO3

b

Cl

c

Br

Scheme 1. Structural formulas of bis(o-anilinium)diselenide salts 1a-c.

ACS Paragon Plus Environment

Crystal Growth & Design 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Various chalcogen-containing moieties have been shown to act as ChB donors,14–16 but to the extent of our knowledge, no diselenide-containing compounds have been used as ChB donors by design.

Page 2 of 14

Table 1. Values and angular positions of 0.001 au VS,max associated with σ-holes of covalently-bonded selenium atoms.

_____________________________

2. RESULTS AND DISCUSSION

Molecule/ Cation

2.1. Electrostatic Potential and Model Compounds Analyses. The electrostatic potential V(r) created by the nuclei and electrons in a molecule or charged molecular species is given rigorously by eq. (1).

Bis(p-nitrophenyl)diselenide (2)

Se-Se C-Se

23 19

168 172

Dicyanodiselenide (3)

Se-Se C-Se

37 41

168 177

Bis(o-anilinium)diselenide (in 1a-c)

C-Se

149

170

V(r )   A

ZA ρ(r)dr  RA  r r  r

(1)

ZA is the charge on nucleus A, located at RA, and ρ(r) is the electronic density function. An important feature of the electrostatic potential is that it is a real physical property, a physical observable. It can be determined experimentally, by diffraction methods,17–19 as well as computationally. In analyzing and interpreting molecule’s noncovalent interactions, V(r) is now commonly computed on the molecule’s “surface”; following the suggestion of Bader et al.,20 this is frequently taken to be an outer contour of the molecule’s electronic density, usually the 0.001 au. It has been demonstrated that the 0.001 au contour typically lies beyond the van der Waals radii of the atoms in the molecule,21 so that V(r) on this surface is relevant to the onset of noncovalent interactions.8,22 The electrostatic potentials presented in this paper have been computed at the M06-2X/6-311G(d) level. Two model moieties, i.e., bis(p-nitrophenyl)diselenide (2) and dicyanodiselenide (3), were investigated to assess general features of ChBs formed by diselenide derivatives. Our focus in this study has been on the positive electrostatic potentials associated with the seleniums in the abovementioned diselenides, particularly on the positions and magnitudes of their most positive VS,max values (most positive values on the 0.001 au surfaces). Figure 1 shows the electrostatic potentials on molecular surfaces of diselenide 2. Each selenium atom has two VS,max. These are associated with σ-holes along the extensions of SeSe and C-Se bonds and both potentials are in the vicinity of 20 kcal/mol (Table 1). Pure crystalline 223 shows only one

Bond

VS,max Angle to VS,max (kcal/mol) (degrees)

______________________________________

and fairly long ChB per selenium atom. In these interactions one oxygen of the nitro group gets close to selenium on the extension of the C–Se covalent bond (the Se∙∙∙O separation is 322.4 pm which correspond to a normalized contact24 Nc = 0.97) and no contacts are found on the extension of Se–Se covalent bond. This is likely a result of the overall crystal packing requirements and the moderately positive character of -holes at seleniums indicating a moderate electrophilic character for these chalcogens. Figures 2 shows the electrostatic potential on molecular surface of dicyanodiselenide. Each selenium atom has two VS,max once again associated with σ-holes along the extensions of Se–Se and C–Se bonds. Consistent with the strong electron withdrawing character of the cyano group, the -hole potentials are quite positive, having values around 40 kcal/mol (Table 1) and in crystals of pure dicyanodiselenide25 each selenium atom of any molecule forms two close and fairly linear Se∙∙∙N ChBs (the two C– Se∙∙∙N and Se–Se∙∙∙N separations are in the range 287.7319.9 pm which correspond to Nc values in the range 0.830.93). Observed Se–Se∙∙∙N angles are 165.35° and 164.33° and C–Se∙∙∙N angles are 172.89° and 178.30°; these values

Se C N

N

Se

C Se

C N

Figure 1. Left: Computed electrostatic potential on the 0.001 au molecular surface of bis(p-nitrophenyl)diselenide (2). Right: Orientation of the molecule (the selenium in the foreground is indicated in bold letters). Color ranges, in kcal/mol: Red, more positive than 24; yellow, between 24 and 15; green, between 15 and zero; blue, negative. The black hemispheres indicate the locations of the most positive potentials, the VS,max, along the extensions of the bonds to the selenium atoms: VS,max (Se-Se): 23.3 kcal/mol; VS,max (C-Se): 19.2 kcal/mol. There are two of each kind, although only one along the extension of the Se-Se bond is visible in the reported figure.

Se

C N

Figure 2. Computed electrostatic potentials on the 0.001 au molecular surface of dicyanodiselenide (3). Two views are shown on left and right with the representation of corresponding molecular orientations reported below (the selenium in the foreground is indicated in bold letters). Color ranges, in kcal/mol: Red, more positive than 30; yellow, between 30 and 15; green, between 15 and zero; blue, negative. The black hemispheres indicate the locations of the most positive potentials, the VS,max, along the extensions of the bonds to the selenium atoms: VS,max (C-Se): 40.9 kcal/mol; VS,max (Se-Se): 37.4 kcal/mol. There are two of each kind, even though not all are visible in the views shown.


Page 3 of 14 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


are in good agreement with calculated Se–Se∙∙∙VS,max and C– Se∙∙∙VS,max values (Table 1). A search in the Cambridge Structural Database (ConQuest 1.22) provides 198 structures containing the C– Se–Se–C moiety and two, or more, neutral nitrogen atoms. In this set, 6 structures show one close Se∙∙∙N ChB per molecule, 34 two close Se∙∙∙N ChBs per molecule, no structure shows exactly three ChBs per molecule, and dicyanodiselenide (3) is the only compound showing four ChBs per molecule. In the co-crystal between dicyanodiselenide and phenyltrimethylammonium bromide, one selenium atom forms one Se∙∙∙N ChB and the other selenium atom gives rise to a particularly short and linear Se∙∙∙Br ChB which substitutes for the two Se∙∙∙N ChBs observed in the pure diselenide 3.26 These literature data suggest that bromide anions, and possibly other anions, are particularly good ChB acceptors and can prevail over neutral lone pair possessing atoms in ChBs formation. The pattern of ChBs present in various bis(imidazolium-2-yl) diselenide salts27,28 supports this generalization and our assumption that crystals of bis(o-anilinium)diselenide salts are likely to present packings formed under ChB control. Figure 3 shows the electrostatic potential on the cationic surface of bis(o-anilinium)diselenide dication. The electrostatic potential is positive on the whole surface, with the most positive regions (shown in red) associated with the NH3+ groups. The VS,max associated with the selenium atoms are along the extension of the C-Se bonds and are much more positive than VS,max of neutral model compounds 2 and 3 (Table 1). The potentials along the extensions of the Se-Se bonds are indeed positive, but corresponding VS,max that might be envisioned are dominated by the NH3+ groups in their vicinities. 2.2. Single crystal X-ray analyses of bis(o-anilinium)diselenide salts 1a-c. In all examined structures, HBs (between anions and hydrogen atoms of ammonium groups) and ChBs (between anions and selenium atoms) are the closest interactions and determine the crystal packing. While some comments will be reported on the HBs, our discussion will focus on the ChBs. 1a crystallize in the P 1 space group and each anion is pinned in its position by three HBs with hydrogen atoms of three different bis(o-anilinium) dications (Figure S1), the mean separation between the oxygen and nitrogen atoms is

+

277.5 pm. In the asymmetric unit of 1a, a well-defined and chalcogen bonded adduct is formed on interaction of the oxygen atoms of two p-toluenesulfonate anions with one selenium atom of the diselenide moiety via two different and fairly linear close contacts (Figure 4, left). Specifically, the C–Se∙∙∙O and Se–Se∙∙∙O angles are 178.69° and 169.20° in the order, and the Se∙∙∙O separations are 327.8 and 331.8 pm long on the extension of the C–Se and Se–Se covalent bonds, respectively. These values correspond to normalized contacts Nc of 0.96 and 0.97. Consistent with the presence of a -hole on the extension of the C–Se covalent bond but not on the extension of the Se–Se bond, the ChB on the extension of the C–Se bond is shorter and more linear than the ChB on the extension of the Se–Se bond and the same occurs in 1b,c (see onwards). The diselenide selenium atoms not involved in Se∙∙∙O ChBs form a short and directional Se∙∙∙C contact with a carbon atom of an adjacent diselenide unit (Figure S3). The Se∙∙∙C separation is 327.4 pm (corresponding to an Nc value of 0.91) and the C–Se∙∙∙C angle is 167.7°; as the two Se∙∙∙C–C angles are 92.53° and 93.87°, the Se∙∙∙C contact seem to be an over the atom interaction. The -hole character of charge assisted12 Se∙∙∙O ChBs in 1a is confirmed by a comparison of these interactions with the XBs formed by anions with iodine atoms of iodonium salts.29,30 Iodine atoms in these λ3-derivatives form two covalent bonds after a geometry similar to that of the two covalent bonds around selenium in diselenides 1. The O∙∙∙Se∙∙∙O angle in 1a is 102.89° and the O∙∙∙I∙∙∙O angle in pmethoxyphenyl-p-perfluorotolyl-iodonium p-toluenesulfonate 4 is 111.30° (Figure 4, right).31 One of the oxygen atoms of two distinct p-toluenesulfonate anions in 4 gets close to the positively charged iodonium atom along the extensions of the two covalent bonds at iodine (where two -holes are positioned) and non-covalent trimers are formed. The perfluorotolyl substituent in 4 is more electron withdrawing than the methoxyphenyl substituent and the XB opposite to the former substituent is shorter and more linear than that opposite to the latter. The two I∙∙∙O separations are 255.4 and 278.0 pm long and the two C– I∙∙∙O angles are 173.24° and 164.08°. Both the chloride 1b and the bromide 1c of bis(oanilinium)diselenide crystallize in the Pccn space group and show isostructural packings with the very same pattern of non-covalent interactions around the diselenide moiety.

Se

H 3N Se

NH3+

Figure 3. Left: Computed electrostatic potential on the 0.001 au molecular surface of the bis(o-anilinium)diselenide dication. The orientation of the dication is shown on the right. The selenium in the foreground is indicated in bold letters in the structural formula. Note that the surface electrostatic potential is entirely positive. Color ranges, in kcal/mol: Red, greater than 183; yellow, between 183 and 158; green, between 158 and 132; blue, less than 132. The black hemisphere indicates the location of the most positive potential, the VS,max, along the extensions of one of the C-Se bonds: VS,max (C-Se): 149 kcal/mol. There are two of these, but only one is visible in the plot. The most positive regions in this dication’s electrostatic potential (shown in red) are associated with the NH3+ groups.

Figure 4. Partial ball and stick representation (Mercury 3.10.2) of chalcogen bonded trimer in 1a (left) and halogen bonded trimer in 3iodonium derivative 4 (right, Refcode: TUXMOP) evidencing the remarkable similarity in the geometric features around the electrophilic selenium and iodine sites. Hydrogen atoms have been omitted; ChBs are black dotted lines, XBs are magenta dotted lines. Color codes: light green, fluorine; violet, iodine; light ocher, sulfur; other colors as in Figure 1.



Page 4 of 14

Figure 6. Partial ball and stick side view (Mercury 3.10.2) of two wavy 2D chalcogen bonded nets in the crystal packing of 1b; piling of strictly similar wavy sheets is present in 1c crystal. ChBs are black dotted lines.

bis-anilinium-diselenide cations act as tetradentate ChB donors and sit at the nodes of the net and halide anions act as bidentate ChB acceptors and bridge two nodes. Tessellation with the parallelograms formed under ChB control gives rise to wavy and two-dimensional (2D) sheets that stack up in the crystal packing (Figure 6). In 1b the C– Se∙∙∙Cl and Se–Se∙∙∙Cl separations are 342.3 pm and 353.0 pm, respectively (corresponding Nc values are 0.92 and 0.95). The C–Se∙∙∙Cl and Se–Se∙∙∙Cl angles are 171.23° and 153.06°. Corresponding separations in 1c are 356.9 and 368.2 pm (Nc values being once again 0.92 and 0.95, respectively) and corresponding angles are 173.34° and 153.31°.

3. CONCLUSIONS

Figure 5. Partial ball and stick representation (Mercury 3.10.2) of one 2D network formed by Se∙∙∙Cl and Se∙∙∙Br in 1b (top) and 1c (bottom); the isoreticularity of two lattices is apparent. Hydrogen atoms have been omitted and ChBs are black dotted lines. Color codes: Grey, carbon; sky blue, nitrogen; ocher, selenium; green, chlorine; brown, bromide.

As in 1a, the landscape of interactions in 1b,c includes both HBs and ChBs. Chloride and bromide anions form three and two HBs with the ammonium hydrogens and mean N∙∙∙halide anion separations are 316.8 and 330.2 pm, respectively. Halides are further pinned in their position by two ChBs, each anion bridging two selenium atoms of two distinct cations by forming one ChB along the C–Se covalent bond and one along the Se–Se covalent bond (Figures 5, S2).32 Each cation of 1b and 1c acts as a donor of four ChBs, two symmetry equivalent ChBs on the elongation of C–Se bond and two symmetry equivalent ChBs on the elongation of Se–Se bond. This pattern of ChBs forms parallelogram-type rings defined by eight ChBs (four of them on the elongation of C–Se bonds and four on the elongation of the Se–Se bonds), four anions and six selenium atoms (belonging to four distinct cations). Topologically speaking, a (4,4)-network is formed wherein

The molecular electrostatic potential of organic diselenides 1-3 shows that regions of depleted electron density, where a positive -hole is located, can be found opposite to both C– Se and Se–Se covalent bonds. Interestingly, in bis(oanilinium)diselenide cation no -hole is observed opposite to the Se–Se bond and this can be rationalized considering that the observed electrostatic potential at any point results from the contributions from both electrons and nuclei of the whole molecular system and in the considered region of this cation the potential is dominated by the nearby NH3+ groups. As typical in -hole interactions, the potential of organic diselenide becomes more positive when residues bound to selenium become more electron withdrawing. Single crystal X-ray analyses of bis(oanilinium)diselenide salts 1a-c revealed the presence of close contacts between anions (acting as donors of electron density, ChB acceptor sites) and selenium atoms (acting as acceptors of electron density, ChB donor sites). Discrete adducts (1a) or two dimensional networks (1b,c) are formed under control of charge assisted ChBs proving that organic diselenides can function as effective tectons in ChB based crystal engineering. The first coordination sphere of different halide anions can be quite different resulting in the formation, for instance, of different hydrogen bonded and halogen bonded supramolecular anions.33,4 The (4,4) chalcogen bonded networks observed in crystalline chloride and bromide salts 1b and 1c are isoreticular, suggesting that the diselenide∙∙∙anion supramolecular synthon may be fairly robust. Organic diselenides can thus be added to the palette of selenium moieties available for controlling molecular conformations or recognition and self-assembly processes.


Page 5 of 14 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Directionality, a consequence of the presence and location of σ-hole(s), is a distinctive geometric feature ChBs. The anisotropic distribution of the electron density at the surface of bis-anilinium-diselenide cation and the linear directionality of close contacts at selenium in 1a-c salts, justifies the rationalization of observed interactions as charge assisted ChBs . Organic diselenides can be easily prepared and can function as effective catalysts of a variety of reactions.34 Importantly, selenocystine has been found in naturally occurring proteins35,36 and when introduced in synthetic proteins enables for more potent bioactivity and enhanced stability.37 A better understanding of the pattern of interactions preferentially formed by organic diselenides may thus impact in numerous fields as different as chemical catalysis and drugs optimization.

■ REFERENCES (1) (2)

(3) (4) (5)

(6)

4. EXPERIMENTAL SECTION X-ray crystallography data acquisition. X-ray diffraction data were collected at Bruker APEX-II diffractometer equipped with sealed-tube and CCD detector, using Mo-Kα radiation (λ=0.71073 Å). The crystals were cryo-cooled (100 K) for data collection using Bruker KRYOFLEX device. Semi-empirical absorption corrections and scaling were performed on datasets, exploiting multiple measures of symmetryrelated reflections, using SADABS program.38 The structures were solved by ShelxS39 and the refinements were carried out by full-matrix least-squares on F2 using the SHELXL program.40 The compound 1a is solvated by a molecule of acetonitrile, which is disordered over two positions. The occupancy for the positions of the CH3CN molecule is fixed at 0.5 and the disorder was refined using EADP command. Pictures were prepared using CCDC Mercury.41 Essential crystal and refinement data are reported in Table S1. Synthesis of bis(o-anilinium)diselenide p-toluensulfonate (1a). Benzoselenazole (0.1 mmol) was dissolved in acetonitrile followed by the addition of 1.2 equivalent of ptoluenesulfonic acid. The solution was prepared at room temperature in a clear borosilicate glass vial which was left open and covered with pierced Parafilm. Good quality single yellow plate crystals of 1a·CH3CN were grown in 3 days by slow evaporation techniques under isothermal conditions at room temperature. Similar procedures were used for the preparation of 1b and 1c.

(7)

(8) (9)

(10) (11)

(12)

(13)

(14)

(15)

■ ASSOCIATED CONTENT The Supporting Information is available free of charge on the ACS Publications website at DOI: Spectral characterization and crystallographic data of 1a-c; CSD analyses; figures of HBs in 1a-c.

(16)

Note The authors declare no competing financial interest.

(17)

■ AUTHOR INFORMATION

(18)

Corresponding Author

(19)

*E-mail: [email protected] ORCID Giuseppe Resnati: 0000-0002-0797-9296 Giancarlo Terraneo: 0000-0002-1225-2577 Patrick Scilabra: 0000-0003-1972-620X

(20) (21)

Hantzsch, A. Die Chromoisomerie Der P‐Dioxy‐terephthalsäure‐Derivate Als Phenol‐Enol‐Isomerie. Berichte der Dtsch. Chem. Gesellschaft 1915, 48, 797–816. Desiraju, G. R.; Ho, P. S.; Kloo, L.; Legon, A. C.; Marquardt, R.; Metrangolo, P.; Politzer, P.; Resnati, G.; Rissanen, K. Definition of the Halogen Bond (IUPAC Recommendations 2013). Pure Appl. Chem. 2013, 85, 1711-1713. Politzer, P.; Murray, J. S. σ-Hole Interactions: Perspectives and Misconceptions. Crystals 2017, 7, 212-226. Cavallo, G.; Metrangolo, P.; Milani, R.; Pilati, T.; Priimagi, A.; Resnati, G.; Terraneo, G. The Halogen Bond. Chem. Rev.. 2016, 116, 2478–2601. Nayak, S. K.; Kumar, V.; Murray, J. S.; Politzer, P.; Terraneo, G.; Pilati, T.; Metrangolo, P.; Resnati, G. Fluorination Promotes Chalcogen Bonding in Crystalline Solids. CrystEngComm 2017, 19, 4955–4959. Scilabra, P.; Terraneo, G.; Resnati, G. Fluorinated Elements of Group 15 as Pnictogen Bond Donor Sites. J. Fluorine Chem. 2017, 203, 62-67. Scilabra, P.; Kumar, V.; Ursini, M.; Resnati, G. Close Contacts Involving Germanium and Tin in Crystal Structures: Experimental Evidence of Tetrel Bonds. J. Mol. Model. 2018, 24, 37. Politzer, P.; Murray, J. S.; Clark, T.; Resnati, G. The σ-Hole Revisited. Phys. Chem. Chem. Phys. 2017, 19, 32166–32178. Brinck, T.; Murray, J. S.; Politzer, P. Surface Electrostatic Potentials of Halogenated Methanes as Indicators of Directional Intermolecular Interactions. Int. J. Quantum Chem. 1992, 44, 57–64. Clark, T.; Hennemann, M.; Murray, J. S.; Politzer, P. Halogen Bonding: The Sigma-Hole. J. Mol. Model. 2007, 13, 291–296. Rowe, R. K.; Ho, P. S. Relationships between Hydrogen Bonds and Halogen Bonds in Biological Systems. Acta Crystallogr. Sect. B Struct. Sci. Cryst. Eng. Mater. 2017, 73, 255–264. Konidaris, K. F.; Pilati, T.; Terraneo, G.; Politzer, P.; Murray, J. S.; Scilabra, P.; Resnati, G. Cyanine Dyes: Synergistic Action of Hydrogen, Halogen and Chalcogen Bonds Allows Discrete I42- Anions in Crystals. New J. Chem. 2018, 42, 10463–10466. Hereinafter a contact and an interaction are considered close, or short, if the distance between the involved atoms is smaller than the sum of the van der Waals radii of involved atoms, or their Pauling ionic radii if charged. Wonner, P.; Vogel, L.; Düser, M.; Gomes, L.; Kniep, F.; Mallick, B.; Werz, D. B.; Huber, S. M. Carbon-Halogen Bond Activation by Selenium-Based Chalcogen Bonding. Angew. Chem. Int. Ed. 2017, 12009–12012. Garrett, G. E.; Carrera, E. I.; Seferos, D. S.; Taylor, M. S. Anion Recognition by a Bidentate Chalcogen Bond Donor. Chem. Commun. 2016, 52, 9881–9884. Ho, P. C.; Szydlowski, P.; Sinclair, J.; Elder, P. J. W.; Kübel, J.; Gendy, C.; Lee, L. M.; Jenkins, H.; Britten, J. F.; Morim, D. R.; Vargas-Baca I. Supramolecular Macrocycles Reversibly Assembled by Te⋯O Chalcogen Bonding. Nat. Commun. 2016, 7, 11299. Stewart, R. F. On the Mapping of Electrostatic Properties from Bragg Diffraction Data. Chem. Phys. Lett. 1979, 65, 335–342. Politzer P.; Truhlar D. G. Chemical Applications of Atomic and Molecular Electrostatic potentials. Plenum Press. 1981. Klein C. L; Stevens E. D. Structure and Reactivity. VCH. 1988, Chapter. 2, pages 25–64. Bader, R. F. W.; Carroll, M. T.; Cheeseman, J. R.; Chang, C. Properties of Atoms in Molecules: Atomic Volumes. J. Am. Chem. Soc. 1987, 109, 7968–7979. Murray, J. S.; Politzer, P. Molecular Surfaces, van Der Waals Radii and Electrostatic Potentials in Relation to Noncovalent Interactions. Croat. Chem. Acta 2009, 82, 267–275.



(22) Murray, J. S.; Politzer, P. Molecular Electrostatic Potentials and Noncovalent Interactions. Wiley Interdisciplinary Reviews: Computational Molecular Science. 2017; DOI: 10.1002/wcms.1326. (23) Morris, G. D.; Einstein, F. W. B. Structure of Bis(pNitrophenyl) Diselenide at 187 K. Acta Crystallogr., Sect. C Cryst. Struct. Commun. 1986, 42, 1433–1435. (24) A normalized contact (Nc) is defined as the ratio of the experimental separation of interacting atoms to the sum of their respective van der Waals radii (or Pauling ionic radii for charged species) (Bondi, A. van der Waals Volumes and Radii. J. Phys. Chem. 1964, 68, 441–451; Shannon, R. D. Revised effective ionic radii and systematic studies of interatomic distances in halides and chalcogenides. Acta Crystallogr. Sect. A 1976, 32, 751–767). A value of Nc < 1 is usually assumed to designate an attractive interaction. Nc is a useful indicator because it allows distances between different interacting partners (therefore interaction strengths) to be compared in a more reliable way than when absolute values of separations are used. (25) Burchell, C. J.; Kilian, P.; Slawin, A. M. Z.; Woollins, J. D.; Tersago, K.; Van Alsenoy, C.; Blockhuys, F. E2(CN)2 (E = S, Se) and Related Compounds. Inorg. Chem. 2006, 45, 710– 716. (26) Hauge, S.; Marøy, K. Reactions between Selenocyanate and Bromine. Syntheses and Crystal Structures of Phenyltrimethylammonium Salts of Dibromoselenocyanate, [C6H5(CH3)3N][SeCNBr2], and Bromodiselenocyanate, [C6H5(CH3)3N][(SeCN)2Br]. Acta Chem. Scand. 1992, 46, 1166–1169. (27) Roy, G.; Bhabak, K. P.; Mugesh, G. Interactions of Antithyroid Drugs and Their Analogues with Halogens and Their Biological Implications. Cryst. Growth Des. 2011, 11, 2279–2286. (28) Choi, J.; Ko, J. H.; Jung, I. G.; Yang, H. Y.; Ko, K. C.; Lee, J. Y.; Lee, S. M.; Kim, H. J.; Nam, J. H.; Ahn, J. R.; et al. Reaction of Imidazoline-2-Selone with Acids and Its Use for Selective Coordination of Platinum Ions on Silica Surface. Chem. Mater. 2009, 21, 2571–2573. (29) Cavallo, G.; Murray, J. S.; Politzer, P.; Pilati, T.; Ursini, M.; Resnati, G. Halogen Bonding in Hypervalent Iodine and Bromine Derivatives: Halonium Salts. IUCrJ 2017, 4, 411– 419. (30) Catalano, L.; Cavallo, G.; Metrangolo, P.; Resnati, G.; Terraneo, G. Halogen Bonding in Hypervalent Iodine Compounds. Top. Curr. Chem. 2016, 373, 289–310. (31) Schäfer, S.; Wirth, T. A Versatile and Highly Reactive

(32)

(33) (34) (35) (36)

(37)

(38) (39) (40) (41)

Page 6 of 14

Polyfluorinated Hypervalent Iodine (III) Compound. Angew. Chem. Int. Ed. 2010, 49, 2786–2789. The analogy of the pattern of ChBs between anions and selenium atoms in the diselenide moiety of 1 salts and XBs between anions and iodine atoms in iodonium salts is further confirmed if the HBs in the coordination sphere of the anions are considered. The ammonium hydrogens enter the coordination sphere of halide anions in 1b,c and form tetramers wherein two opposite vertices are the anions and the other two vertices are one selenium atom and one ammonium group. Similar supramolecular adducts are present in the crystal lattice of ionic λ3-iodane derivatives; for instance in otolyl-phenyl-iodonium chloride (Refcode: UZOGUN) tetramers are present wherein two opposite vertices are the anions and the other two vertices are one iodine atom and one phenyl ring (Figure S4). Also the compound with Refcode FAKPAL gives tetramers. White, N. G.; MacLachlan, M. J. Chem. Sci. 2015, 6, 6245– 6249 Wirth T. Organoselenium Chemistry. Wiley-VCH, Weinhaim. 2012. Liu, J.; Zhang, Z.; Rozovsky, S. Selenoprotein K Forms an Intermolecular Diselenide Bond with Unusually High Redox Potential. FEBS Lett. 2014, 588, 3311–3321. Shchedrina, V. A.; Novoselov, S. V.; Malinouski, M. Y.; Gladyshev, V. N. Identification and Characterization of a Selenoprotein Family Containing a Diselenide Bond in a Redox Motif. Proc. Natl. Acad. Sci. 2007, 104, 13919–13924. Medini, K.; Harris, P. W. R.; Menorca, A.; Hards, K.; Cook, G. M.; Brimble, M. A. Synthesis and Activity of a Diselenide Bond Mimetic of the Antimicrobial Protein Caenopore-5. Chem. Sci. 2016, 7, 2005–2010. Sheldrick G. M. SADABS, University of Göttingen, Germany, 2012. Sheldrick, G. M. A Short History of SHELX. Acta Crystallographica Section A: Foundations of Crystallography. 2008, A64, 112–122. Sheldrick, G. M. Crystal Structure Refinement with SHELXL. Acta Crystallogr. Sect. C Struct. Chem. 2015, 71, 3–8. Macrae, C. F.; Bruno, I. J.; Chisholm, J. A.; Edgington, P. R.; McCabe, P.; Pidcock, E.; Rodriguez-Monge, L.; Taylor, R.; Van De Streek, J.; Wood, P. A. Mercury CSD 2.0 - New Features for the Visualization and Investigation of Crystal Structures. J. Applied Cryst. 2008, 41, 466–470.


Page 7 of 14 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


For Table of Contents Use Only

Chalcogen Bonds in Crystals of Bis(o-anilinium)diselenide Salts Patrick Scilabra,† Jane S. Murray,‡ Giancarlo Terraneo,† Giuseppe Resnati†*

Synopsis: Combined computational, single crystal X-ray crystallographic and Cambridge Structural Database studies have been presented in order to highlight the propensity of selenium atom in diselenide moiety to works as electrophilic. Therefore, in bis(o-anilinium)diselenide cation the diselenide moiety can be labelled as a novel and robust charge assisted chalcogen bond (ChB) donor group.



Figure 1. Left: Computed electrostatic potential on the 0.001 au molecular surface of bis(pnitrophenyl)diselenide (2). Right: Orientation of the molecule (the selenium in the foreground is indicated in bold letters). Color ranges, in kcal/mol: Red, more positive than 24; yellow, between 24 and 15; green, between 15 and zero; blue, negative. The black hemispheres indicate the locations of the most positive potentials, the VS,max, along the extensions of the bonds to the selenium atoms: VS,max (Se-Se): 23.3 kcal/mol; VS,max (C-Se): 19.2 kcal/mol. There are two of each kind, although only one along the extension of the Se-Se bond is visible in the reported figure. 180x110mm (600 x 600 DPI)


Page 8 of 14

Page 9 of 14 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Figure 2. Computed electrostatic potentials on the 0.001 au molecular surface of dicyanodiselenide (3). Two views are shown on left and right with the representation of corresponding molecular orientations reported below (the selenium in the foreground is indicated in bold letters). Color ranges, in kcal/mol: Red, more positive than 30; yellow, between 30 and 15; green, between 15 and zero; blue, negative. The black hemispheres indicate the locations of the most positive potentials, the VS,max, along the extensions of the bonds to the selenium atoms: VS,max (C-Se): 40.9 kcal/mol; VS,max (Se-Se): 37.4 kcal/mol. There are two of each kind, even though not all are visible in the views shown. 229x140mm (600 x 600 DPI)



Figure 3. Left: Computed electrostatic potential on the 0.001 au molecular surface of the bis(oanilinium)diselenide dication. The orientation of the dication is shown on the right. The selenium in the foreground is indicated in bold letters in the structural formula. Note that the surface electrostatic potential is entirely positive. Color ranges, in kcal/mol: Red, greater than 183; yellow, between 183 and 158; green, between 158 and 132; blue, less than 132. The black hemisphere indicates the location of the most positive potential, the VS,max, along the extensions of one of the C-Se bonds: VS,max (C-Se): 149 kcal/mol. There are two of these, but only one is visible in the plot. The most positive regions in this dication’s electrostatic potential (shown in red) are associated with the NH3+ groups. 180x110mm (600 x 600 DPI)


Page 10 of 14

Page 11 of 14 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Figure 4. Partial ball and stick representation (Mercury 3.10.2) of chalcogen bonded trimer in 1a (left) and halogen bonded trimer in λ3-iodonium derivative 4 (right, Refcode: TUXMOP) evidencing the remarkable similarity in the geometric features around the electrophilic selenium and iodine sites. Hydrogen atoms have been omitted; ChBs are black dotted lines, XBs are magenta dotted lines. Color codes: light green, fluorine; violet, iodine; light ocher, sulfur; other colors as in Figure 1. 209x89mm (600 x 600 DPI)



Figure 5. Partial ball and stick representation (Mercury 3.10.2) of one 2D network formed by Se∙∙∙Cl and Se∙∙∙Br in 1b (top) and 1c (bottom); the isoreticularity of two lattices is apparent. Hydrogen atoms have been omitted and ChBs are black dotted lines. Color codes: Grey, carbon; sky blue, nitrogen; ocher, selenium; green, chlorine; brown, bromide. 120x239mm (600 x 600 DPI)


Page 12 of 14

Page 13 of 14 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Figure 6. Partial ball and stick side view (Mercury 3.10.2) of two wavy 2D chalcogen bonded nets in the crystal packing of 1b; piling of strictly similar wavy sheets is present in 1c crystal. ChBs are black dotted lines. 180x120mm (600 x 600 DPI)



2469x1389mm (72 x 72 DPI)


Page 14 of 14

Chalcogen Bonds in Crystals of Bis(o-anilinium)diselenide Salts

Recommend Documents