Preparation and Crystallography of 1, 2-Bis (chloromercurio

Preparation and Crystallography of 1,2-Bis(chloromercurio)tetrafluorobenzene Adducts with Nitrobenzene and Nitrotoluenes Andrey A. Yakovenko,† Jose H. Gallegos,† Mikhail Yu. Antipin,†,‡ and Tatiana V. Timofeeva*,†

CRYSTAL GROWTH & DESIGN 2009 VOL. 9, NO. 1 66–76

Department of Natural Sciences, New Mexico Highlands UniVersity, Las Vegas, New Mexico 87701, and A. N. NesmeyanoV Institute of Organoelement Compounds, Russian Academy of Sciences, VaViloV St. 28, 119991 Moscow, Russia ReceiVed June 22, 2008; ReVised Manuscript ReceiVed October 20, 2008

ABSTRACT: Co-crystallization of 1,2-bis(chloromercurio)tetrafluorobenzene (II) with nitrobenzene (1) and three nitrotoluene isomers (2-4) results in four complexes with a ratio of organometallic to organic components of 1:1 and one complex with a corresponding ratio of 2:1. All crystals of complexes with a 1:1 ratio have a platelike shape, while crystals of the complex with a 2:1 ratio are needlelike. X-ray studies reveal supramolecular organization in the 1:1 “plate” complexes, showing that they are built of molecular layers where the central section of layers is stabilized with nonbonded interactions of Hg atoms, while the layer surface is formed with phenyl rings of both co-crystal components. Two types of layer superposition in these complexes were found: parallel, producing an acentric structure, and antiparallel, that leads to a centrosymmetric space group. This indicates that supramolecular organization involving Hg nonbonded interactions in some cases will be helpful to produce acentric structures of polar molecules by incorporating them in co-crystals with II. In the 2:1 complex, molecules are organized in 1D associates (chains), that are stabilized with the same types of interactions. In both types of complexes, external crystal shape corresponds to internal supramolecular organization in co-crystals: platelike layered and needlelike chain crystals. Introduction Lewis acids (LA) such as bidentate 1,2-bis(chloromercurio)benzene, o-(C6H4)(HgCl)2 (I), and 1,2-bis(chloromercurio)tetrafluorobenzene, o-(C6F4)(HgCl)2 (II), or cyclic tridentate perfluoro-o-phenylmercury, o-(C6F4Hg)3 (III) (Scheme 1), are found to easily form adducts with organic ionic and neutral electron-rich compounds via supramolecular organization and particular orientation of the guest molecules. Adduct formation can influence catalytic activity and solid state polymerization, prevent decomposition of unstable guest molecules, transform spectral behavior of guests, and so forth. Numerous examples of complexes of LA III have been studied, and their structure, properties, and applications have been described in reviews by Shur and Tikhonova,1 and Gabbaı¨ et al.2 A significantly lower number of examples of complexes with LA I and II have been considered,2 and only about 10 such adducts have been characterized by X-ray analysis.2 It was shown that due to the low ability of Hg atoms to participate in the Hg · · · O interactions not many adducts with I are found.3-5 Respective fluorinated species II were found to form adducts with a variety of compounds2,6-10 containing terminal oxo or nitrilo functionalities including ketones,8 formamides,8 sulfoxides,6 phosphonate diesters,7 aldehydes,9 nitriles,9 and epoxides.9 Most of these adducts are aliphatic functionalized compounds that have a symmetrical chelate type of oxygen atom coordination with both Hg atoms of bidentate II. Only one aromatic compound (benzaldehyde) was found to form an adduct with II. It is worth mentioning that this adduct has an acentric crystal structure9 and the ligand molecule is bonded to only one Hg atom of II. * To whom correspondence should be addressed. Mailing address: Department of Natural Sciences, New Mexico Highlands University, Las Vegas, NM 87701. Telephone: (505)454 3362. Fax: (505)454 3202. E-mail: [email protected]. † New Mexico Highlands University. ‡ A. N. Nesmeyanov Institute of Organoelement Compounds.

Our present work was motivated by the following factors. We were looking for supramolecular organization that can modify the centrosymmetric structure of individual nitro materials11,12 (Scheme 2) into an acentric structure of host-guest components. Such an approach can alter, for instance, organization of polar donor-acceptor molecules and make them useful for applications as optoelectronic materials in the form of thin crystalline films or single crystals. There are several ways to manipulate supramolecular organization to produce an acentric structure. First, the most successful approach for organic nonlinear optical (NLO) materials is the creation of mixed crystals built of polar organic cations and organic anaions such as organic salt 4-dimethylamino-Nmethyl-4-stilbazolium tosylate (DAST) and other organic salts,13-21 where the formation of acentric crystals is determined by charge-charge, dipole-dipole, and higher order interactions. Many but not all DAST analogues exhibit an acentric structure, which is probably based on a delicate balance of electrostatic and other (π-stacking, etc) interactions, that, in this case, are stronger than those in mixed crystals of neutral molecules. A second approach to manipulate supramolecular organization is based on the specific architecture of hydrogen bonds, which results in acentricity of the final product. In this case, both individual compounds and mixed crystals with different ratios of components can be used22-25 for crystal design. The most obvious pathway to acentricity is a co-crystallization of polar molecules with enantiomerically pure components, such as amino acids.26,27 This approach always results in noncentrosymmetric crystals, and attempts to orient polar molecules in parallel fails since molecules are packed in an acentric crystal in a quasicentrosymmetric manner. Some other approaches to orient polar guest molecules in channels of a host crystal28 or columnar mixed octupolar crystals29 are also discussed in the literature. Until now, there have been no reliable theoretical considerations that can predict a priori supramolecular organization in a crystal

10.1021/cg8006603 CCC: $40.75  2009 American Chemical Society Published on Web 12/04/2008

1,2-Bis(chloromercurio)tetrafluorobenzene Adducts

Crystal Growth & Design, Vol. 9, No. 1, 2009 67 Scheme 1

Scheme 2

nitromethane, and 2-nitropropane (Scheme 3) that led to isolation of complexes of nitroaromatics with a bifunctional Lewis acid II. Experimental Section

to determine its acentric structure. Therefore, experimental investigations of new types of supramolecular organization leading to acentricity are useful. We explore supramolecular organization based on nonbonded interactions of positively charged mercury atoms in LA II, negatively charged chlorine atoms of LA II, and oxygen atoms belonging to the second component of the adduct. LA II and III can form adducts with different compounds that are liquid at room temperature.1,2 Preparation of these complexes is usually straightforward1-10 and often gives single crystals of adducts that are suitable for X-ray diffraction analysis. Hence, such an approach can be used for experimental investigation of the molecular structure of compounds that are liquid at room temperature. Here, we report our findings in the host-guest chemistry of II with a series of nitroaromatic compounds 1-4, nitroaliphatic

Compound II was prepared and purified according to the literature procedure.30 All other compounds were obtained commercially and used without further purification. Elemental analysis of carbon, hydrogen, and nitrogen was carried out with an Elementar Vario EL III microanalyzer. The infrared spectra were recorded on a Nicolet MagnaIR 550 FT-IR spectrometer over the frequency range 4000-400 cm-1 using the Nujol mulls technique. General Procedure for the Preparation of the 1,2-Bis(chloromercurio)tetrafluorobenzene (II) Adducts with Liquid Nitrobenzene (1), orto-Nitrotoluene (3), and meta-Nitrotoluene (4). A suspension was created by adding solid II to each nitro compound. The suspension was heated to give a homogeneous solution, from which colorless single crystals of the complex were obtained upon cooling to room temperature or slow evaporation. Crystals of the complex were filtered, washed with Et2O (3 × 5 mL), and dried in air. Complexes were obtained with quantitative yield. Preparation of adducts with ratios of components 1:1 (II · 4) and 2:1 (2(II) · 4) differs in the relative amounts of reagents used. Freshly obtained crystals were used for single crystal X-ray diffraction analysis. In air, clear crystals of adducts are rapidly transformed to a white powder. Preparation of {[C6F4Hg2Cl2][PhNO2]}n (II · 1) Adduct. Adduct II · 1 was prepared from nitrobenzene (0.5 mL) and compound II (65 mg, 0.1 mmol). Single platelike crystals of complex II · 1 formed upon

Scheme 3

Results and Discussion In the case of nitroaliphatic compounds, II dissolves instantly in a small amount of nitromethane and 2-nitropropane. Upon slow evaporation, pure II spontaneously crystallizes, resulting in no adduct. This is an unusual result for the “host-guest” chemistry of II, since, as we mentioned above, ligands such as ketones, formamides, sulfoxides, phosphonate diesters, nitriles, and epoxides always form complexes2 with II. However, as mentioned in ref 9, compound II does not produce adducts with aliphatic aldehydes. On the other hand, II rapidly produce cocrystals with aromatic aldehydes (benzaldehyde); therefore, we carried out co-crystallization of II with a series of aromatic nitrocompounds such 1-4. Using a small volume (0.5 mL) of a guest as the solvent and by slow cooling of the resulting solution, we obtained crystalline adducts of II and nitroaromatic

2(II) · 4

C19H7Cl4F8Hg4NO2 monoclinic P21/n 7.0904(13) 35.056(7) 11.140(2) 105.870(3) 2663.5(9) 4 2416 3.435 23.463 0.50 × 0.05 × 0.02 27929 7016 [R(int) ) 0.0463] R1 ) 0.0534, wR2 ) 0.1120 R1 ) 0.0651, wR2 ) 0.1169 1.010 2.373 and -1.323 C13H7Cl2F4Hg2NO2 monoclinic P21 7.1236(16) 7.3554(17) 15.543(4) 101.201(3) 798.9(3) 2 676 3.148 19.577 0.30 × 0.20 × 0.10 8605 4166 [R(int) ) 0.0306] R1 ) 0.0261, wR2 ) 0.0539 R1 ) 0.0291, wR2 ) 0.0551 1.002 1.252 and -0.814

II · 4 II · 3

C13H7Cl2F4Hg2NO2 monoclinic P21/n 7.1522(11) 7.5536(12) 29.920(5) 92.123(2) 1615.3(4) 4 1352 3.114 19.365 0.50 × 0.30 × 0.10 16573 4263 [R(int) ) 0.0293] R1 ) 0.0437, wR2 ) 0.0945 R1 ) 0.0484, wR2 ) 0.0968 1.001 2.444 and -2.157 C13H7Cl2F4Hg2NO2 monoclinic P21/n 7.0963(12) 7.3024(12) 30.832(5) 93.973(2) 1593.9(5) 4 1352 3.156 19.625 0.56 × 0.23 × 0.04 15902 4178 [R(int) ) 0.0452] R1 ) 0.0408, wR2 ) 0.0914 R1 ) 0.0460, wR2 ) 0.0938 1.000 2.549 and -1.373

II · 2 II · 1

C12H5Cl2F4Hg2NO2 monoclinic P21 7.127(3) 7.181(3) 15.042(7) 99.976(8) 758.2(6) 2 660 3.256 20.626 0.49 × 0.13 × 0.04 7397 3576 [R(int) ) 0.0397] R1 ) 0.0392, wR2 ) 0.0877 R1 ) 0.0430, wR2 ) 0.0898 0.999 2.405 and -0.893

cooling to room temperature. For II · 1: IR (cm-1): 1616 (w), 1603 (w), 1519 (s), 1423 (s), 1345 (s), 1315 (w), 1007 (m), 849 (w), 821 (m), 792 (w). Anal. Calcd for C12H5Cl2F4Hg2NO2 (%): C, 19.39; H, 0.68; N, 1.88. Found (%): C, 19.21, H, 0.34; N, 1.65. The same adduct can be synthesized when 2 mL of nitrobenzene and slow cooling are used. Preparation of {[C6F4Hg2Cl2][para-CH3C6H4NO2]}n (II · 2). A mixture of para-nitrotoluene (696 mg) and compound II (65 mg, 0.1mmol) was heated in an oil bath until all para-nitrotoluine melted. The mixture was heated to give a homogeneous solution, from which colorless platelike crystals of complex II · 2 formed. The excess of solvent was decanted, and resulting mixture was cooled down to room temperature. Crystals of II · 2 were washed with Et2O (3 × 5 mL), filtered, and dried in air. For II · 2: IR (cm-1): 1616 (w), 1597 (w), 1514 (s), 1421 (s), 1344 (s), 1311 (w), 1008 (m), 822 (m). Anal. Calcd for C13H7Cl2F4Hg2NO2 (%): C, 20.62; H, 0.93; N, 1.85. Found (%): C, 20.49; H, 0.99; N, 1.63. Preparation of {[C6F4Hg2Cl2][orto-CH3C6H4NO2]}n (II · 3). Adduct II · 3 was prepared from orto-nitrotoluene (0.5 mL) and compound II (65 mg, 0.1 mmol). Single platelike crystals of complex II · 3 formed upon cooling to room temperature. For II · 3: IR (cm-1): 1611 (w), 1580 (w), 1518 (s), 1421 (s), 1347 (s), 1004 (m), 821 (m). Anal. Calcd for C13H7Cl2F4Hg2NO2 (%): C, 20.62; H, 0.93; N, 1.85. Found (%): C, 20.78; H, 0.85; N, 1.52. The same adduct can be synthesized when 2 mL of 3 and slow cooling are used. Preparation of {[C6F4Hg2Cl2][meta-CH3C6H4NO2]}n (II · 4). Adduct II · 4 was prepared from meta-nitrotoluene (0.5 mL) and compound II (65 mg, 0.1 mmol). Single platelike crystals of complex II · 4 formed upon cooling to room temperature. For II · 4: IR (cm-1): 1616 (w), 1586 (w), 1523 (s), 1344 (s), 1314 (w), 1005 (m), 822 (m), 800 (w), 771 (w). Anal. Calcd for C13H7Cl2F4Hg2NO2 (%): C, 20.62; H, 0.93; N, 1.85. Found (%): C, 20.52; H, 1.12; N, 1.75. Preparation of {[C6F4Hg2Cl2]2[meta-CH3C6H4NO2]}n (2(II) · 4). Adduct 2(II) · 4 was prepared from meta-nitrotoluene (2 mL) and compound II (65 mg, 0.1 mmol). Needlelike single crystals of complex 2(II) · 4 formed after slow evaporation at room temperature for 3 days. For 2(II) · 4: IR (cm-1): 1614 (w), 1586 (w), 1524 (s), 1421 (s), 1344 (s), 1007 (m), 820 (w), 800 (w), 769 (vw). Anal. Calcd for C19H7Cl4F8Hg4NO2 (%): C, 16.57; H, 0.51; N, 1.02. Found (%): C, 16.91; H, 0.23; N, 1.24. Single Crystal X-ray Diffraction Analysis. Crystal data, details of data collection, and structure refinement parameters for complexes II · 1-II · 4 are presented in Table 1. The X-ray diffraction experiment was carried out with a Bruker SMART APEX II diffractometer with a CCD area detector (graphite monochromated Mo KR radiation, l ) 0.71073 Å, ω-scans with a 0.5° step in ω) at 100 K. The semiempirical method SADABS31 was applied for absorption correction of complexes II · 1 and 2(II) · 2. For other complexes, the numerical absorption correction has been used. Structures were solved by direct methods and refined by the full-matrix least-squares technique against F2 with anisotropic temperature parameters for all non-hydrogen atoms. All H atoms were geometrically placed and refined in the riding model approximation. Data reduction and further calculations were performed using the Bruker SAINT+32 and the SHELXTL NT33 program packages.

Yakovenko et al.

formula cryst syst space group a, Å b, Å c, Å β, deg V, Å3 Z F(000) Dcalcd, g/cm3 µ, mm-1 cryst size, mm3 no. of rfls collected (RC) no. of indep RC (IRC) final R indices [I > 2σ(I)] R for IRC goodness of fit largest diff peak and hole, eÅ-3

Crystal Growth & Design, Vol. 9, No. 1, 2009

Table 1. Crystal Data Collection and Structure Refinement Details

68


Crystal Growth & Design, Vol. 9, No. 1, 2009 69

Figure 1. Microscope photograph (a) of typical 1:1 complex (II · 4) plate crystals, synthesized by slow cooling of the solution of compound II in 0.5 mL of the nitrocompound and (b) of needlelike crystals of complex 2(II) · 4, synthesized by slow evaporation of the compound II solution in 2 mL of 4.

compounds (Figure 1a), with the general formula {[C6F4Hg2Cl2][ArNO2]}n (where Ar ) Ph(II · 1), p-MeC6H4(II · 2), o-Me-C6H4(II · 3), m-Me-C6H4(II · 4)) (Scheme 3). All four complexes have a 1:1 ratio of components and are characterized by the platelike crystal shape shown in Figure 1a. We decided to name such adducts “plate” complexes. We also repeated the co-crystallization of II with a larger volume of liquid nitrocompounds 1-4. The reaction with compound 4 led to the colorless needlelike crystals (Figure 1b) of {[C6F4Hg2Cl2]2[m-CH3C6H4NO2]}n (2(II) · 4). The adduct contains two molecules of Lewis acid per one molecule of nitroaromatic ligand. In the case of compounds 1-3, reactions attain the previously described platelike complexes. The IR spectra of complexes in Nujol display the νas(NO) and νs(NO) bands. In II · 1-II · 4, at least one of these bands is shifted to lower wavenumbers, relative to the corresponding bands in the spectrum of the noncoordinated nitrocompound. The comparison of coordinated and uncoordinated νas(NO) and νs(NO) bands is presented in the Supporting Information (Table 1S). A similar effect is found in the complex of III with nitrobenzene.34 Structure of “Plate” Complexes. In the reactions between II and nitrocompounds, two types of complexes were synthesized, which differ by the ratio of Lewis acid and ligand. The first type of 1:1 complexe is obtained for all four aromatic nitrocompounds 1-4. In all of these adducts, a structure with similar layers coplanar to the (001) plane (Figure 2), which combines molecules II and nitroaromatic molecules, is found. Geometrical parameters for molecule II in complexes, and its comparison with the previously studied structure9 of noncoordinated II, are presented in the Supporting Information. Molecules of II in the “plate” complexes are essentially planar (Supporting Information, Table 2S). The Hg-Cl distances for all “plate” complexes are in a range of 2.310(3)-2.317(2) Å. The C-C bonds in the benzene rings are close to the normal values. However, the distance of C(1)-C(2) is slightly longer than that of the other bonds. This can be explained by steric interactions of two Hg-Cl groups in the orto positions. Such

an effect is also found in the molecular structure of individual compound II, which has a geometry almost identical to the geometry of coordinated molecule II. In complexes II · 1-II · 4, the mercury atoms Hg(1) and Hg(2) have different types of coordination (Figure 3), which can be described as distorted trigonal and tetragonal bypyramids, respectively. We assume that covalently bonded chlorine and carbon atoms of the C6F4HgCl fragment occupy the “axial” positions, whereas the “equatorial” positions are occupied by nonbonded chorine and oxygen atoms. In the case of Hg(1), the “equatorial” plane contains two chlorine atoms and one oxygen atom, while the corresponding plane of Hg(2) includes three chlorine atoms and one oxygen atom (Figure 3b). The deviations of Hg atoms from the equatorial plane in complexes II · 1-II · 4 are small (0.19-0.30 and 0.00-0.15 Å for Hg(1) and Hg(2), respectively). The nonbonded distances Hg · · · X (X ) O and Cl) for the trigonal bipyramidal arrangement are smaller than those for the tetragonal bipyramidal one (see the Supporting Information). Molecules of II in crystals of complexes II · 1-II · 4 are linked with Cl · · · Hg interactions, which help to stabilize the layered structure. The Cl · · · Hg nonbonded distances are shorter than the sum of the van der Waals radii of Hg and Cl (rvdw(Cl) ) 1.58-1.78 Å,35 rvdw(Hg) ) 1.73-2.00 Å36) (Table 2). Table 2 and Figure 4 show that each chlorine atom of II participates in a different number of Cl · · · Hg intermolecular interactions. As shown in Figure 4, the chlorine atom Cl(1) forms three Cl · · · Hg bonds with two different molecules II (Cl(1) · · · Hg(1A) and Cl(1) · · · Hg (2A) first, and Cl(1) · · · Hg(2B) second). The second chlorine atom Cl(2) is coordinated to only two mercury atoms Hg(1C) and Hg(2C). The distances Cl(1) · · · Hg in all complexes II · 1-II · 4 are in the range of 3.173-3.289 Å, while the Cl(2) · · · Hg distances differ significantly. The average intermolecular distance Cl(2) · · · Hg(1C) (3.11 Å) is smaller than the average distance Cl(2) · · · Hg(2C) (3.51 Å) by 0.4 Å. Similar coordination of chlorine atoms was found in complexes II with acetone,7 propylene oxide,9 and benzaldehyde.9

70


Yakovenko et al. Table 2. Cl · · · Hg Short Contacts in “Plate” Complexes parameter [Å]† Cl(1) · · · Hg(1A) Cl(1) · · · Hg(2A)a Cl(1) · · · Hg(2B)b Cl(2) · · · Hg(1C)c Cl(2) · · · Hg(2C)c a

II · 1

II · 2

II · 3

II · 4

3.18 3.27 3.17 3.12 3.46

3.21 3.26 3.21 3.10 3.49

3.26 3.29 3.27 3.07 3.52

3.21 3.25 3.21 3.16 3.55

For II · 1: a -x + 1, y + 0.5, -z + 1; b x, y + 1, z; c -x, y - 0.5, -z; for II · 2: a -x + 1.5, y + 0.5, -z + 0.5; b x, y + 1, z; c -x + 0.5, y - 0.5, -z + 0.5; for II · 3: a -x - 0.5, y - 0.5, -z + 0.5; b x, y - 1, z; c -x + 0.5, y + 0.5, -z + 0.5; for II · 4: a -x + 2, y + 0.5, -z + 3; b x, y + 1, z; c -x + 1, y - 0.5, -z + 3. †

Figure 4. Coordination of chlorine atoms in “plate” complexes (for II · 1: A, -x + 1, y + 0.5, -z + 1; B, x, y + 1, z; C, -x, y - 0.5, -z; for II · 2: A, -x + 2, y + 0.5, -z + 3; B, x, y + 1, z; C, -x + 1, y 0.5, -z + 3; for II · 3: A, -x - 0.5, y - 0.5, -z + 0.5; B, x, y - 1, z; C, -x + 0.5, y + 0.5, -z + 0.5; for II · 4: A, -x + 1.5, y + 0.5, -z + 0.5; B, x, y + 1, z; C, -x + 0.5, y - 0.5, -z + 0.5).

Figure 2. Layers in crystal packing of typical chiral (a) II · 1 and centosymmetric (b) II · 2 1:1 complexes.

Figure 3. Coordination of atoms: (a) Hg(1) and (b) Hg(2) in complexes II · 1-II · 4.

Complexes II · 1 and II · 4 are isostructural to the complex with benzaldehyde,9 II · 2 and II · 3 have very similar structures and doubled parameters c, and therefore, the Cl · · · Hg interactions have a similar pattern. However, the Cl · · · Hg contacts are slightly longer (Cl(1) · · · Hg, 3.210-3.244 Å; Cl(2) · · · Hg(1), 3.247 Å; Cl(2) · · · Hg(2), 3.531 Å) than those for complexes with nitroaromatic components. In the case of acetone7 and propylene

oxide9 complexes, one of the chlorine atoms, Cl(1), has similar coordination. Another atom, Cl(2), is bonded to mercury atoms from two different molecules of II. The value of the coordination angle Hg · · · Cl(2) · · · Hg is close to 180°, while in complexes of II, with nitrocompounds and benzaldehyde, the value of the corresponding angle is completely different (64.52-68.23°) (Figure 4). Molecules of nitroaromatic compounds and II in II · 1-II · 4 are linked into chains by two N-O · · · Hg interactions (Figure 5). These interactions give additional stabilization of the layered structure in “plate” complexes. Usually, in complexes of II with neutral molecules, the oxygen (or nitrogen) atom of a ligand is coordinated with both mercury atoms of molecule II. Therefore, these complexes have a chelate structure. On the contrary, in our case, a chain pattern occurs. In complexes II · 1-II · 4, the Hg · · · O distances (Table 3) are shorter than the sum of the van der Waals radii of oxygen (1.54 Å)35 and mercury (1.73-2.00 Å)36 and are in the range 3.005(6)-3.149(6) Å (av ) 3.08 Å), which is slightly longer than average Hg · · · O distances (3.02 Å) previously found in a complex of III with nitrobenzene (1) {[(o-C6F4Hg)3](PhNO2)}34 (III · 1). Complexes II · 1 and III · 1 have the same ratio of nitrobenzene and LA molecules; however, adduct III · 1 has a pyramidal structure, where the molecule of nitrobenzene is coordinated only with one molecule of III, and the formation of a polydecker structure as in refs 37 and 38 was not found. Shorter Hg · · · O distances in complex III · 1 give a reason to believe that the Hg · · · O interaction in this complex is stronger than that in II · 1. Similar conclusions about LA-ligand interactions have been done when arene complexes of bis(pentaphenyl)mercury were compared with corresponding complexes of



Figure 5. Molecular chains built of Lewis acid (II) and Lewis bases (1-4) found in crystals of “plate” complexes II · 1 (a), II · 2 (b), II · 3 (c), and II · 4 (d) along the [-2 2 1] direction. Table 3. Hg · · · O Short Contacts in “Plate” Complexes parameters

II · 1

II · 2

II · 3

II · 4

Hg(1) · · · O(1) (Å) Hg(2) · · · O(2) (Å)

3.04(1) 3.11(1)

3.005(6) 3.149(6)

3.051(7) 3.091(7)

3.089(6) 3.115(6)

III and where a higher affinity of LA III for arenes was related to their high quenching efficiency.39 The geometrical parameters of ligands 1-4 in the complexes, in comparison with those previously found in structures of noncoordinated nitrocompounds,11,12 are presented in the Sup-

porting Information. Inclusion of nitroaromatic molecules into complexes with II do not alter structural characteristics of coordinated molecules 1-4; however, complex formation changes the relative orientation of the nitro group around the C(7)-N(1) bond. It is interesting that in complexes II · 1, II · 2, and II · 4 the dihedral angle between the planes of the nitro group and phenyl ring is approximately 20° (Supporting Information, Table 9S), while isolated molecules of nitrobenzene,11 mnitrotoluene,12 and p-nitrotoluene12 have essentially a planar structure. In complex II · 3, where the corresponding interplanar

72


Yakovenko et al. Table 4. Important Geometrical Parameters of Stacking Interactions in “Plate” Complexes† parameters

II · 1

II · 2

II · 3

II · 4

CRF · · · CRH (Å) CRF* · · · CRH (Å) ∠(PLF; PLH) (deg) ∠(PLF*; PLH) (deg) CRF · · · PLH (Å) CRF* · · · PLH (Å) shift CRF · · · CRH (Å) shift CRF* · · · CRH (Å)

3.58 3.79 6.27 6.27 3.44 3.48 0.99 1.50

3.54 3.71 5.26 5.26 3.43 3.44 0.87 1.39

3.57 3.72 9.63 9.63 3.53 3.44 0.54 1.41

3.67 3.96 3.72 3.72 3.34 3.41 1.52 2.01

† CRF, centroid of phenyl ring in II; CRH, centroid of phenyl ring in 1-4; PLF, mean plane via phenyl ring in II; PLH, mean plane via phenyl ring in 1-4; x + 1, y, z for complex II · 3; x, y - 1, z for complex II · 1; x, y + 1, z for complex II · 4; x - 1, y, z for complex II · 2.

Figure 6. (a) Stacking interactions in a column in a typical “plate” complex II · 1 (along the a-axis), and projections on the staking column in crystallographic plane a for (b) II · 1, (c) II · 2, (d) II · 3, and (e) II · 4.

angle is obviously defined by the intramolecular contact of NO2 and Me groups, it is larger than that in 1, 2, and 4 (34.5°) and is close to the angle in noncoordinated molecule 3 (31.8°).12 From Figure 5, it can be seen that molecules of II and ligands are linked not only by Hg · · · Cl and Hg · · · O interactions but also by π-π staking interactions of the tetrafluorinated aromatic

Figure 7. Notations for stacking interactions presented in Table 4.

ring of II and the nitrobenzene ring. It is worth mentioning that these pairs stack on each other and produce columns in which tetrafluorobenzene units and aromatic rings of the ligand are alternated (Figure 6a). A comprehensive description of the geometry parameters of π-π stacking is presented in Table 4 and Figure 7. The aromatic rings in π-π stacked columns are not exactly parallel (3.7-9.6°); therefore, we describe the distances between the mean planes of those rings as distances between the centroids of tetrafluorinated rings and the average plane of the nitroaromatic ring (CRF · · · PLH) (Figure 7). These distances inside the pairs and between the pairs are almost identical (Table 4). However, the shift of centroids in molecular pairs (CRF · · · CRH: 0.54-1.52 Å) is smaller than the same shift of centroids between the pairs (CRF* · · · CRH: 1.39-2.01 Å). It is interesting that the value of the shift, CRF · · · CRH, for complex II · 4 is large (1.52 Å) (Figure 6e) in comparison to all other “plate” complexes (0.54-0.99 Å) (Figure 6b-d). Similar staking interaction has been found earlier in a complex of II with benzaldehyde.9 The co-crystallization of II with aliphatic aldehydes and nitrocompounds does not produce stable adducts, and at the same time the aromatic compounds with similar functionalities easily form such complexes. It is understandable that in the case of aliphatic compounds the staking interaction is unfeasible; therefore, in aliphatic materials, we can observe only Hg · · · O interactions, while aromatic compounds can also demonstrate π-π staking interactions. Hence,



Figure 10. Molecular chains in the crystal structure of complex 2(II) · 4 along the a-axis.

Figure 8. Unit cells of typical chiral (a) (II · 1) and centosymmetric (b) (II · 2) “plate” complexes.

we can suppose that the energy of Hg · · · O interactions in the case of aliphatic aldehydes and nitrocompounds is not sufficient to produce stable adducts. Finally we can say that in all “plate” complexes we found three types of intermolecular interactions: Hg · · · Cl interactions between molecules of Lewis acid, Hg · · · O interactions between nitrogoroups of the ligand and mercury atoms of II, and π-π stacking interactions between tetrafluorobenzene units of II and aromatic rings of the ligand. In co-crystals, II · 1-II · 4 molecules of II and 1-4 are linked into layers along b by all types of interactions described above (Figure 2). It is seen that all polar interactions (Cl · · · Hg, and O · · · Hg) are concentrated inside the layer and nonpolar π-π (staking) interactions between the aromatic rings are located close to the layer surface. That makes interlayer interactions significantly weaker than intralayer ones. From this discussion, we can conclude that all of the “plate” complexes might be isostructural. However, it is found that complexes II · 1 and II · 4 crystallize in a chiral space group P21,

Figure 11. Coordination of atoms: (a) Hg(1A), (b) Hg(1B), Hg(2A), and Hg(2B) and in complex 2(II) · 4.

while complexes II · 2 and II · 3 have a centrosymmetric space group P21/n (Table 1). The main difference between centosymmetric and noncentrosymmetric “plate” complexes is the packing of the layers, which are parallel in chiral complexes and antiparallel in centrosymmetric complexes (Figures 2 and 8). As a consequence, centrosymmetric complexes have two layers per unit cell, while noncentrosymmetric complexes have just one, so its unit cell parameter c is two times smaller than that in centrosymmetric crystals. The presence of inversion symmetry in the crystals of “plate” complexes reflects the layer superposition. This allows us to speculate that for similar complexes we might expect the probability of an acentric structure equal to 50% (see, for instance, II · 1 and II · 4), which is significantly higher than the statistical probability to find an acentric structure in the Cambridge Structural Database. So, with this particular supramolecular organization, we were able to modify a centrosymmetric structure of individual materials11,12 into an

Figure 9. (a) Crystal morphology of a “plate” complex II · 4 and (b) a needlelike crystal of complex 2(II) · 4.

74


Yakovenko et al.

Figure 12. (a) Stacking interactions in a column in complex 2(II) · 4 along the [3 -2 1] direction, and (b) projection of column in the crystallographic (3 -2 1) plane.

Figure 13. Molecular crystal packing for complex 2(II) · 4.

acentric structure of molecular complexes. We found earlier a similar situation, where crystal acentricity was modified with layer superposition for polymorphs of organic nonlinear optical materials.40 Crystals of representative examples of complexes II · 1-II · 4 with a platelike shape are shown in Figure 1a. We evaluated the crystal morphology of one of these complexes II · 4 using the APEX II diffractometer and APEX 2 software41 (Figure 9a). Crystal II · 4 has two most developed crystalline faces with indices {001}, that shows that this face is coplanar to the (001) plane, that is, coplanar to molecular layers found in the crystals. Most probably, intralayer interactions are significantly stronger than interlayer interactions. Therefore, the most developed faces are parallel to the layer with the strongest intermolecular energy.42 We can speculate that the energy of intralayer interactions is so strong that a change of ligand does not affect the habit of “plate” complexes crystals. Crystal Structure of Complex 2(II) · 4. When the amount of compound 4 in the reaction with II was 4 times larger than that in previous reactions, we obtained colorless needlelike crystals (Figure 1b) of {[C6F4Hg2Cl2]2[m-CH3C6H4NO2]}n (2(II) · 4). This adduct contains two molecules of Lewis acid per one molecule of nitroaromatic ligand. The crystals of 2(II) · 4 were obtained by slow evaporation of the solvent, in contrast to the synthesis of “plate” complexes, where we used slow cooling as the crystallization condition.

Complex 2(II) · 4 contains chains, which are built with molecules of II and 4 in the ratio 2:1 (Figure 10). The molecular geometry of II in complex 2(II) · 4 does not differ from its geometry in the “plate” complexes and in the individual9 compound II (see Supporting Information Table 1S). There are two symmetrically independent molecules II (A and B) in complex 2(II) · 4 that include four independent mercury atoms (Hg(1A), Hg(2A), Hg(1B), and Hg(2B)), which have different intermolecular environments (Figure 11). Here, as before, we assume that covalently bonded chlorine and carbon atoms from the C6F4HgCl fragment occupy the “axial” positions. The “equatorial” plane of each mercury atom is occupied by a different number of chlorine and oxygen atoms that have contact with mercury, shorter than that in the case of standard nonbonded interactions. The coordination of atoms Hg(1A) and Hg(1B) can be described as a distorted tetragonal bypyramid with four nonbonded atoms in “equatorial” positions (Figure 11a,b). All positions around the Hg(1B) atom are taken by chlorine atoms, while the Hg(1A) atom is surrounded by one oxygen and three chlorine atoms. The Hg(2A) atom has a “seesaw” coordination (Figure 11c); the Hg(1B) atom has the coordination presented in Figure 11d, which is similar to a “seesaw” coordination but contains three chlorine atoms in the “equatorial” plane (see the Supporting Information). In the chains (Figure 10), neighboring molecules of II interact by Hg · · · Cl contacts, whose lengths are shorter than the sum of the van der Waals radii. Molecular chains in this complex are stabilized as in the “plate” complexes mostly by the Hg · · · Cl intermolecular interactions. A molecule of m-nitrotoluene is linked to only one Hg atom (Figures 10 and 11a), so this interaction does not produce additional stabilization of a chain fragment, while in “plate” complexes the NO2 group is a bridging group between two molecules of II and so additionally stabilizes the layered structure of these complexes. In 2(II) · 4, the Hg(1A) · · · O(1)


bond (2.95(1) Å) is significantly shorter than the sum of the van der Waals radii of Hg and O atoms. The geometrical parameters of m-nitrotoluene in complex 2(II) · 4 are presented in the Supporting Information (Table 9S). The distance N-O in fragment N(1)-O(1) · · · Hg(1) (1.229(18) Å) is somewhat larger than that for the noncoordinated N-O bond (N(1)-O(2), 1.207(19) Å). The dihedral angle between the planes of the nitro group and the phenyl ring in complex 2(II) · 4 (14.8°) is smaller than that in complex II · 4. We can speculate that such a value occurs in 2(II) · 4 because in this case only one oxygen atom is coordinated with the Hg center. In complex 2(II) · 4, the stacking interactions between tetrafluorobenzene units and aromatic rings of m-nitrotoluene which produce dimers, similar to what we observed in “plate” complexes, were found (Figure 12). The angle between the mean planes of these two rings is equal to 8.66°, and the distance between the centroid of the aromatic ring in II and the mean plane of the aromatic ring in 4 (CRF · · · PLH ) 3.42 Å) is slightly larger than that in “plate” complexes. The shift of the centroids is equal to 1.12 Å, which is larger than that for other “plate” complexes, except for complex II · 4. The dimers are stacked together forming tetramers, as presented in Figure 12. The distance between mean planes of the two m-nitrotoluene aromatic rings in the tetramer is 3.65 Å. The results of the morphology evaluation of crystal 2(II) · 4 are presented in Figure 9b. This crystal has two “long” faces {010} and {001} along the needle direction [100]. As we mentioned above, complex 2(II) · 4 contains chains that are extended along the crystallographic axis a or [100] direction. Inside these chains, molecules are connected with strong Hg · · · Cl interactions, while between chains slight stacking π-π interactions are observed (Figure 13). It should be noted that the experimental morphology of crystal 2(II) · 4 (needlelike shape along the [100] direction) corresponds to it internal structure (chains along the [100] direction). Conclusion Our attempts to obtain mixed crystals of II with nitrocompounds show that the reactions with aliphatic nitrocompounds do not yield any complexes, while aromatic nitrocompounds, such as nitrobenzene and nitrotoluenes, produce complexes with different ratios of components. Crystals of complexes II · 1-II · 4 with a ratio of II and the nitrocompound of 1:1 have a platelike shape that corresponds to a layered internal structure of these crystals. Two of four plate complexes have acentric structures, which might be an indication that supramolecular organization involves Hg nonbonded interactions. This observation will be helpful in producing acentric structures of polar molecules by incorporating them into similar mixed crystals. In the case of m-nitrotoluene, we obtained complex 2(II) · 4 with a ratio of components of 2:1. The needlelike morphology of 2(II) · 4 crystals corresponds to a chain structure of this material. It was shown that mercury atoms in complexes of II and nitrocompounds have a large variety of coordination types: from “seesaw” (two nonbonded atoms in the coordination sphere of Hg) to distorted tetragonal bipyramid (four nonbonded atoms in the coordination sphere of Hg). Therefore, new data obtained in this study can be used for future reevaluation of an old value of the van der Waals radii of mercury atoms.36 Acknowledgment. We gratefully acknowledge support from STC MDITR, NSF/DMR Grant 0120967, and New Mexico


NSF/EPSCoR Nanoscience Initiative, NSF/DMR Grant 0420863, and from Dr. Kurt W. Short for help with manuscript preparation. Supporting Information Available: X-ray crystallographic information files for structures of complexes II · 1-II · 4 and 2(II) · 4 (CIF); shifts of νas(NO) and νs(NO) vibration bands in IR spectra of complexes of II with nitro compounds (PDF); geometrical parameters of molecule II in complexes and compressing of those parameters with previously investigated structure of uncoordinated II (PDF); description of mercury atom coordination in II · 1-II · 4 and 2(II) · 4 (PDF); molecular geometrical parameters of compounds 1-4 in complexes with compound II and comparison with geometrical parameters of uncoordinated compounds 1-4 complexes (PDF). This material is available free of charge via the Internet at http://pubs.acs.org.

References (1) Shur, V. B.; Tikhonova, I. A. Russ. Chem. Bull. 2003, 52, 2539. (2) Taylor, T. J.; Burress, C. N.; Gabbaı¨, F. P. Organometallics 2007, 26 (22), 5252. (3) Wuest, J. D.; Zacharle, B. Organometallics 1985, 4, 410. (4) Beauchamp, A. L.; Oliver, M. J.; Wuest, J. D.; Zacharie, B. J. Am.Chem. Soc. 1986, 108, 73. (5) Beauchamp, A. L.; Oliver, M. J.; Wuest, J. D.; Zacharie, B. Organometallics 1987, 6, 153. (6) Tschinkl, M.; Schier, A.; Riede, J.; Gabbaı¨, F. P. Angew. Chem., Int. Ed. 1999, 38, 3547. (7) Tschinkl, M.; Bachman, R. E.; Gabbaı¨, F. P. Organometallics 2000, 19, 2633. (8) Tschinkl, M.; Schier, A.; Riede, J.; Gabbaı¨, F. P. Organometallics 1999, 18, 1747. (9) Beckwith, J. D.; Tschinkl, M.; Picot, A.; Tsunoda, M.; Bachman, R.; Gabbaı¨, F. P. Organometallics 2001, 20, 3169. (10) Gardinier, J. R.; Gabbaı¨, F. P. J. Chem. Soc., Dalton Trans. 2000, 2861. (11) Boese, R.; Blaser, D.; Nussbaumer, M.; Krygowski, T. M. Struct. Chem. 1992, 3, 363. (12) Yakovenko, A. A.; Antipin, M. Yu.; Timofeeva, T. V. Cryst. Growth Des. 2009, 9, 57. (13) Okada, S.; Matsuda, H.; Nakanishi, H.; Kato, M.; Muramatsu, R. Japan Patent Application, 61-192404, 1986. (14) Marder, S. R.; Perry, J. W.; Schaefer, W. P. Science 1989, 245, 626. (15) Marder, S. R.; Perry, J. W.; Yakymyshyn, C. P. Chem. Mater. 1994, 6, 1137. (16) Glavcheva, Z.; Umezawa, H.; Mineno, Y.; Odani, T.; Okada, S.; Ikeda, S.; Taniuchi, T.; Nakanishi, H. Jpn. J. Appl. Phys. 2005, 44, 5231. (17) Follonier, S.; Fierz, M.; Biaggio, I.; Meier, U.; Bosshard, Ch.; Gu¨nter, P. J. Opt. Soc. Am. B 2002, 19, 1990. (18) Ruiz, B.; Yang, Z.; Gramlich, V.; Jazbinsek, M.; Gu¨nter, P. J. Mater. Chem. 2006, 16, 2839. (19) Yang, Z.; Wo¨rle, M.; Mutter, L.; Jazbinsek, M.; Gu¨nter, P. Cryst. Growth Des. 2007, 7, 83. (20) Mutter, L.; Brunner, F. D. J.; Yang, Z.; Jazbinsek, M.; Gu¨nter, P. J. Opt. Soc. Am. B 2007, 24, 2556. (21) Koshima, H.; Hamada, M.; Yagi, I.; Uosaki, K. Cryst. Growth Des. 2001, 1, 467. (22) Etter, M. C. J. Phys. Chem. 1991, 95, 4601. (23) Etter, M. C.; Frankenbach, G. M. Chem. Mater. 1989, 1, 10. (24) Zyss, J.; Nicoud, J. F.; Coquillay, M. J. Chem. Phys. 1984, 81, 4160. (25) Nesterov, V. V.; Antipin, M. Yu.; Nesterov, V. N.; Penn, B. G.; Frazier, D. O.; Timofeeva, T. V. Cryst. Growth Des. 2004, 4, 521. (26) Timofeeva, T. V.; Kuhn, G. H.; Nesterov, V. V.; Nesterov, V. N.; Frazier, D. O.; Penn, B. G.; Antipin, M. Yu. Cryst. Growth Des. 2003, 3, 383. (27) Jagadish, B.; Carducci, M. D.; Bosshard, C.; Gunter, P.; Margolis, J. I.; Williams, L. J.; Mash, E. A. Cryst. Growth Des., 2003, 3, 811. (28) Konig, O.; Burgi, H. B.; Armbruster, T.; Hulliger, J.; Weber, T. J. Am. Chem. Soc. 1997, 119, 10632. (29) Zyss, J.; Ledoux-Rak, I.; Weiss, H.-C.; Blaser, D.; Boese, R.; Thallapally, P. K.; Thalladi, V. R.; Desiraju, G. R. Chem. Mater. 2003, 15, 3063. (30) Massey, A. G.; Al-Jabar, N. A. A.; Humphries, R. E.; Deacon, G. B. J. Organomet. Chem. 1986, 316, 25. (31) Sheldrick, G. M. SADABS, Absorption Correction Program, v. 2.01; Bruker AXS: Madison, WI, 1998. (32) SAINTPlus, Data Reduction and Correction Program, v. 6.01; Bruker AXS: Madison, WI, 1998.

76


(33) Sheldrick, G. M. SHELXTL, Structure Determination Software Suite, v. 5.10; Bruker AXS: Madison, WI, 1998. (34) Tikhonova, I. A.; Tugashov, K. I.; Dolgushin, F. M.; Yakovenko, A. A.; Petrovskii, P. V.; Furin, G. G.; Zaraisky, A. P.; Shur, V. B. J. Organomet. Chem. 2007, 692, 953. (35) Nyburg, S. C.; Faerman, C. H. Acta Crystallogr., Sect. B: Struct. Sci. 1985, 41, 274. (36) Canty, A. J.; Deacon, G. B. Inorg. Chim. Acta 1980, 45, L225. (37) Tsunoda, M.; Gabbaı¨, F. P. J. Am. Chem. Soc. 2003, 125, 10492. (38) Haneline, M. R.; Gabbaı¨, F. P. Inorg. Chem. 2005, 44, 6248.

Yakovenko et al. (39) Burress, C. N.; Bodine, M. I.; Elbjeirami, O.; Reibenspeis, J. H.; Omary, M. A.; Gabbaı¨, F. P. Inorg. Chem. 2007, 46, 1388. (40) Timofeeva, T. V.; Nesterov, V. N.; Dolgushin, F. M.; Zubavichus, Y. V.; Goystein, J. T.; Sammeth, D. M.; Clark, R. D.; Penn, B.; Antipin, M. Yu. Cryst. Eng. 2000, 3, 263. (41) APEX 2, Molecular Analysis Research Tool, v. 1.27; Bruker AXS: Madison, WI, 2005. (42) Berkovitch-Yellin, Z. J. Am. Chem. Soc. 1985, 107, 8239.

CG8006603

Preparation and Crystallography of 1, 2-Bis (chloromercurio

Recommend Documents