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Bis(catecholato-κ2O,O′)bis­­(di­methyl sulfoxide-κO)titanium(IV)

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aDepartment of Chemistry, University of Connecticut, Storrs, CT 06269-3060, USA, and bDepartment of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN, 47907-2084, USA
*Correspondence e-mail: c.bruckner@uconn.edu

Edited by J. Reibenspies, Texas A & M University, USA (Received 23 February 2022; accepted 8 March 2022; online 15 March 2022)

Bis(benzene-1,2-diolato-κ2O,O′)bis­(dimethyl sulfoxide-κO)titanium(IV), [Ti(C6H4O2)2(C2H6OS)2], crystallizes with two crystallographically independent mol­ecules in the space group P21/c emulating ortho­rhom­bic Pbca symmetry (β = 90.0445 (9)°]. The two mol­ecules are related by pseudo-glide symmetry, broken by modulation of each one catecholate and dimethyl sulfoxide (DMSO) ligand. Twinning by pseudomerohedry was observed [twin ratio 0.5499 (7):0.4401 (7)]. Complex 3 was obtained by heating of diprotonated titanium tris-catecholate precursor 2H in DMSO, by formal displacement of a catechol mol­ecule by two DMSO mol­ecules. Complex 3 is just the second heteroleptic, mono-nuclear, neutral bis-catecholate complex with TiO6 metal coordination, the only other one being its bis-DMF analogue 6. The two mol­ecules of 3 exhibit a distorted octa­hedral geometry. The geometry and distortions from ideal symmetry of 3 are discussed and compared to 6 and to cationic tris-catecholate titanium complexes.

1. Chemical context

The dianion of catechol (1,2-di­hydroxy­benzene, CatH, 1) is a bidentate, dianionic and non-innocent O,O-chelating agent with a particularly high affinity for HSAB hard-metal ions, i.e., ions of high oxidation states or high charge-to-metal-ion-radius ratios (Pierpont & Lange, 1994[Pierpont, C. G. & Lange, C. W. (1994). Prog. Inorg. Chem. 41, 331-442.]; Kaim & Schwederski, 2010[Kaim, W. & Schwederski, B. (2010). Coord. Chem. Rev. 254, 1580-1588.]). Titanium(IV) is one such metal ion and long known to form stable, pseudo­octa­hedral tris­catecholate complexes, such as 2Et3NH, by reaction of catechol with Ti4+ sources under basic conditions (Fig. 1[link]) (Borgias et al., 1984[Borgias, B. A., Cooper, S. R., Koh, Y. B. & Raymond, K. N. (1984). Inorg. Chem. 23, 1009-1016.]).

[Figure 1]
Figure 1
Formation of titanium(IV) catecholate complexes, including the title compound 3.

Titanium catecholate complexes have found various uses: Titanium tris­catecholate complexes of the alkaline earth metals were utilized as mol­ecular precursors to a number of MIITiO6-type perovskites (Ali & Milne, 1987[Ali, N. J. & Milne, S. J. (1987). British Ceram. Trans. J. 86, 113-117.]; Marteel-Parrish et al., 2008[Marteel-Parrish, A., DeCarlo, S., Harlan, D., Martin, J. & Sheridan, H. (2008). Green Chem. Lett. Rev. 1, 197-203.]). Titanium catecholates have been exploited as catalysts in acetyl­ene hydrogenation (Bazhenova et al., 2016[Bazhenova, T. A., Kovaleva, N. V., Shilov, G. V., Petrova, G. N. & Kuznetsov, D. A. (2016). Eur. J. Inorg. Chem. pp. 5215-5221.]) while three-dimensional titanium catecholate frameworks of high proton conductivity (Nguyen et al., 2015[Nguyen, N. T. T., Furukawa, H., Gándara, F., Trickett, C. A., Jeong, H. M., Cordova, K. E. & Yaghi, O. M. (2015). J. Am. Chem. Soc. 137, 15394-15397.]) and titanium catecholate-based MOFs have been described (Cao et al., 2020[Cao, J., Ma, W., Lyu, K., Zhuang, L., Cong, H. & Deng, H. (2020). Chem. Sci. 11, 3978-3985.]). Metal catecholates have been suggested as adsorbents for toxic gases (Bobbitt & Snurr, 2018[Bobbitt, N. S. & Snurr, R. Q. (2018). Ind. Eng. Chem. Res. 57, 17488-17495.]). Titanium tris­catecholates were also used to self-assemble a potential bimodal contrast agent (Dehaen et al., 2012[Dehaen, G., Eliseeva, S. V., Kimpe, K., Laurent, S., Vander Elst, L., Muller, R. N., Dehaen, W., Binnemans, K. & Parac-Vogt, T. N. (2012). Chem. Eur. J. 18, 293-302.]). A number of heteroleptic mono- and multi-nuclear titanium complexes do contain titanium catechol units (Sakata et al., 2010[Sakata, Y., Hiraoka, S. & Shionoya, M. (2010). Chem. Eur. J. 16, 3318-3325.]; Bazhenova et al., 2016[Bazhenova, T. A., Kovaleva, N. V., Shilov, G. V., Petrova, G. N. & Kuznetsov, D. A. (2016). Eur. J. Inorg. Chem. pp. 5215-5221.]; Sonström et al., 2019[Sonström, A., Schneider, D., Maichle-Mössmer, C. & Anwander, R. (2019). Eur. J. Inorg. Chem. pp.682-692.]; Passadis et al., 2020[Passadis, S. S., Papanikolaou, M. G., Elliott, A., Tsiafoulis, C. G., Tsipis, A. C., Keramidas, A. D., Miras, H. N. & Kabanos, T. A. (2020). Inorg. Chem. 59, 18345-18357.]) (for further examples, see Database survey below). Most prominently, titanium tris-catecholates have been used as versatile building blocks in a range of supra­molecular, oligonuclear homo- and hetero-metal-ligand cluster assemblies (Brückner et al., 1998[Brückner, C., Powers, R. E. & Raymond, K. N. (1998). Angew. Chem. Int. Ed. 37, 1837-1839.]; Caulder et al., 2001[Caulder, D. L., Brückner, C., Powers, R. E., König, S., Parac, T. N., Leary, J. A. & Raymond, K. N. (2001). J. Am. Chem. Soc. 123, 8923-8938.]; Albrecht et al., 2008[Albrecht, M., Burk, S. & Weis, P. (2008). Synthesis, pp. 2963-2967.], 2019[Albrecht, M., Chen, X. & Van Craen, D. (2019). Chem. Eur. J. 25, 4265-4273.]).

Reaction of TiCl4 under anhydrous conditions in toluene generates a brick-colored amorphous powder of the diproton­ated titanium tris-catecholate complex 2H (Davies & Dutremez, 1990[Davies, J. A. & Dutremez, S. (1990). J. Am. Ceram. Soc. 73, 1429-1430.]). We found that this compound dissolves sufficiently enough in ambient-temperature DMSO-d6 to record a simple 1H NMR spectrum, showing only two multiplets of equal integration (at 6.84 and 6.75 ppm), corres­ponding to the ortho- and meta-hydrogens on three near-identical catecholate moieties (the counter-cations – protons – are believed to be dynamically associated with the trigonal faces of the pseudo-octa­hedral coordination sphere formed by the six catecholate oxygens) (Fig. 2[link]A). Upon heating 2H in DMSO (or DMSO-d6), its solubility increases drastically. When followed by 1H NMR spectroscopy, the formation of a new species with two catecholate signals (m at 6.42 and 6.12 ppm, in 2:2 intensity) and 1 equivalent of free catechol (m at 6.73 and 6.60, br s at 8.1 ppm, all 1:1:1) can be observed (Fig. 2[link]B). Upon cooling, dark red–orange crystals of the title compound 3 formed. Isolated and analyzed by NMR spectroscopy, they exhibit only the signals for the new species formed (Fig. 2[link]C) and the signals for two slightly high-field-shifted DMSO mol­ecules (not shown).

[Figure 2]
Figure 2
1H NMR spectra (400 MHz, DMSO-d6) of (A) complex 2H dissolved at ambient temperature; (B) of complex 2H at ∼373 K, showing the presence of complex 3 and free catechol 1; (C) of isolated crystals of 3 precipitated from DMSO at ambient temperature (* indicates the presence of residual 1).

The material was also analyzed by single crystal X-ray diffraction (Fig. 3[link]). Evidently, one protonated catecholate ligand (i.e., catechol 1) of the starting tris­catcholate complex 2H was exchanged for two DMSO mol­ecules, coordinating through their oxygen atoms in adjacent positions, thus forming a neutral, heteroleptic, mononuclear octa­hedral complex. Details of the structural arrangement will be discussed in the Structural commentary section below.

[Scheme 1]
[Figure 3]
Figure 3
The two crystallographically independent mol­ecules of 3. View along the a axis. Mol­ecules A and B are related by pseudo-glide operations (see discussion for details).

The UV–vis spectrum of the orange solution of 3 is overall similar to that of the starting material 2H; both spectra are dominated in the visible range by broad, little-structured catecholate ligand-to-metal charge-transfer bands (for 3, lmax = 441 nm; half-height width > 150 nm; Fig. 4[link]). In comparison to the spectrum of 2H, all bands for 3 are bathochromically shifted.

[Figure 4]
Figure 4
Normalized UV–vis spectrum of title compound 3 (DMSO) in comparison to that of the starting tris­catecholate 1 (H2O).

2. Structural commentary

The title complex 3, having solution C2 symmetry, crystallizes as a racemic mixture with two crystallographically independent mol­ecules in the monoclinic space group P21/c (Fig. 3[link]). For both mol­ecules, the solution C2 symmetry is broken in the solid state, and the Ti atoms are each bonded to two chelating catecholate and two monodentate O-coordinated di­methyl­sulfoxide ligands. The Ti—OCat bond distances range from 1.9113 (19) to 1.9564 (18) Å in mol­ecule A, and 1.9108 (18) to 1.9545 (18) in mol­ecule B [average 1.93 (3) Å]. A notable structural trans-effect is observed as the longer distances are observed for the oxygen atoms opposite another catechol oxygen donor atom [1.9346 (18) to 1.9564 (18) Å] while the shorter distances [1.9108 (18) to 1.9284 (19) Å] are found trans to the weaker electron-donating ODMSO atoms.

The Ti—OCat bond distances in the cationic tris­catecholate complex 2Et3NH are on average longer [1.97 (3) vs 1.93 (3) Å in 3], ranging from 1.941 (1) to 2.014 (1) Å with differences between long and short Ti—O bonds caused by distortion from strong hydrogen bonds to the Et3NH+ counter-cations (reflected in a 0.05 Å lengthening of the associated Ti—O bonds) (Borgias et al., 1984[Borgias, B. A., Cooper, S. R., Koh, Y. B. & Raymond, K. N. (1984). Inorg. Chem. 23, 1009-1016.]). The four Ti—ODMSO bond distances in 3 are at 2.0214 (19) to 2.0416 (18) Å significantly longer than the Ti—OCat bond lengths, as would be expected for neutral and uncharged DMSO ligands.

The bond lengths in 3 also compare well with those of the [bis­catecholate-bis-DMF]titanium complex 6, the DMF analogue to the title compound (Bazhenova et al., 2016[Bazhenova, T. A., Kovaleva, N. V., Shilov, G. V., Petrova, G. N. & Kuznetsov, D. A. (2016). Eur. J. Inorg. Chem. pp. 5215-5221.]) and the only other reported heteroleptic mono-nuclear and uncharged bis-catecholate titanium complex with MO6 metal coordination (see Database survey). The Ti—Ocat bond lengths in 6 are 1.9003 (12) and 1.9181 (12) Å for the oxygen atoms trans to the DMF mol­ecules, 1.9408 (11) and 1.9483 (11) Å when trans to another Ocat atom, and 2.0396 (12) and 2.0736 (12) Å for the Ti—ODMF bond lengths. They thus closely mirror those found in 3.

The small bite angles of the chelating catecholate anions induce substantial distortions from idealized octa­hedral symmetry. The catecholate O—Ti—O angles in 3 are 80.73 (7) and 81.00 (8)° in mol­ecule A and 80.85 (8) and 80.24 (8)° in mol­ecule B, which are essentially indistinguishable from those in 2Et3NH [80.1 (1) to 80.6 (1)°] and 6 [O3 80.68 (5) and O2 80.97 (5)°]. The other cis angles in 3 cover a wide range from as small as 82.35 (7)° (for the ODMSO—Ti—ODMSO angle in mol­ecule A) to as large as 105.30 (8)° (for one of the Ocat—Ti—ODMSO angles in mol­ecule B). The latter rather obtuse large angle is unique in being nearly 4° wider than the next largest angle [its equivalent in mol­ecule A is 101.66 (8)°]. The angles in 2Et3NH do not exceed 101.3°. The equivalent angles in the DMF analogue 6 are more evenly distributed than in either mol­ecule of 3, ranging from 82.53 (5) to 97.77 (5)°.

This more pronounced deviation from ideal octa­hedral symmetry for mol­ecule B of 3 is also confirmed by a more holistic analysis, using a normalized root-mean-square deviation algorithm to calculate the distortion from octa­hedral symmetry as implemented in the program SHAPE (Pinsky & Avnir, 1998[Pinsky, M. & Avnir, D. (1998). Inorg. Chem. 37, 5575-5582.]; Alvarez et al., 2002[Alvarez, S., Avnir, D., Llunell, M. & Pinsky, M. (2002). New J. Chem. 26, 996-1009.]; Casanova et al., 2004[Casanova, D., Cirera, J., Llunell, M., Alemany, P., Avnir, D. & Alvarez, S. (2004). J. Am. Chem. Soc. 126, 1755-1763.]). The calculated continuous shape measures (CShM's) relative to ideal reference octa­hedral symmetry are 1.434 for 2Et3NH, 1.513 for 6, 1.491 for less distorted mol­ecule A of 3, and 1.854 for mol­ecule B (Table 1[link]). Shape measures may be between 0 and 100 where zero represents a perfect fit for the selected shape, and CShM values of less than 1.0 are usually inter­preted as only minor distortions from the reference shape. Values between 1 and 3 indicate substantial distortions, but the reference shape still provides a good stereochemical description (Cirera et al., 2005[Cirera, J., Ruiz, E. & Alvarez, S. (2005). Organometallics, 24, 1556-1562.]). For the four cases analyzed here, the CShM's for the next best fit, trigonal prismatic, are all around 10 (Table 1[link]). The geometries of 3, 6 and 2Et3NH are thus best described as distorted octa­hedral, being far removed from fitting any other polygon.

Table 1
Continuous shape measures (CShM's) relative to ideal reference octa­hedral symmetry for 2Et3NH, 3 and 6

Structure Hexagon Penta­gonal pyramid Octa­hedron Trigonal prism Johnson penta­gonal pyramid J2
2Et3NH 33.773 23.482 1.434 9.808 27.215
3A 32.792 22.191 1.491 10.655 26.183
3B 32.830 21.007 1.854 10.159 24.952
6 33.664 22.467 1.513 10.069 26.511

The two independent mol­ecules in compound 3 are related to each other by crystallographic pseudosymmetry. Complex 3 crystallized in a pseudo-ortho­rhom­bic setting with a refined β angle of 90.0445 (9)°, and emulates space group Pbca with additional b- and a-glide operations along the a- and c-axis directions. Exact translational symmetry is broken by modulation of one of the catecholate and one of the DMSO ligands, as discussed below. The metric pseudosymmetry allows for the possibility of twinning. Indeed, the crystal investigated was found to be pseudo-merohedrically twinned by symmetry elements of the emulated ortho­rhom­bic symmetry. Application of the twin transformation matrix 1 0 0, 0 −1 0, 0 0 −1 yielded close to equal twin components with a refined twin ratio of 0.5499 (7) to 0.4401 (7).

A root-mean-square overlay of the two mol­ecules yields an r.m.s. deviation of 0.459 Å, indicating substantial variation between the geometries of mol­ecules A and B (Fig. 5[link]). A similar overlay based on only the titanium and oxygen atoms gives a much smaller value of only 0.056 Å, indicating that the main differences between the two complexes is rooted in the ligands, even though there are small and noticeable differences for the TiO6 cores as well (with mol­ecule B deviating more from ideal octa­hedral symmetry than mol­ecule A, as discussed above). The main distinction between the two mol­ecules is, however, associated with substantial twists and torsions of the catecholate and DMSO ligands. The r.m.s. overlay reveals a close match of one of the catecholate ligands and one of the DMSO ligands. The other catecholate and DMSO ligands, on the other hand, do show substantial variation between the two mol­ecules. The catecholate of C7–C12 undergoes a twist-motion by a slight rotation around the Ocat—Ocat axis. In mol­ecule A (blue in the overlay), the catecholate ligand is close to coplanar with the titanium atom, while in mol­ecule B (red in the overlay) the catecholate and the TiO(Cat)2 plane are clearly angled against each other. The deviations of the Ti atoms from the mean catecholate planes are 0.049 (2) and 0.349 (2) Å for mol­ecules A and B, respectively. The angle between the mean catecholate and Ti(OCat)2 planes is 1.97 (9)° for complex A, but a much larger value of 13.6 (8)° for complex B.

[Figure 5]
Figure 5
Root-mean-square overlays of the two independent mol­ecules of 3, after inversion of mol­ecule B (red: mol­ecule A; blue: mol­ecule B). Left: fit based on all non-H atoms (r.m.s. deviation 0.459 Å). Right: fit based on Ti and O atoms only (r.m.s. deviation 0.056 Å).

The other main difference between the two mol­ecules is a rotation of about 14° for one of the two DMSO ligands around the Ti—O bond, which can be expressed via the torsion angle O5—Ti1—O6—S2 (S2 is the sulfur atom of the rotated DMSO ligand, O5 the oxygen atom of the other invariant DMSO ligand). These torsion angles are 165.13 (16)° for mol­ecule A, and 151.10 (14)° for mol­ecule B. The largest overall motion is observed for the DMSO methyl groups of C15 [1.774 (3) Å in the r.m.s. overlay based on the titanium and oxygen atoms].

The differences in mol­ecular geometry between mol­ecules A and B and the modulation by pseudo-ortho­rhom­bic symmetry are closely related, showing mol­ecules A and B as they are related to each other by a pseudo b-glide perpendicular to (100) (Fig. 6[link]). In addition to the variations in mol­ecular geometry seen in the mol­ecule overlay, a very slight rotation of the entire complex is also observed.

[Figure 6]
Figure 6
View of 3 down the c axis, showing the modulation by pseudo-Pbca symmetry. Mol­ecules color coded by symmetry equivalence (red: mol­ecule A, blue mol­ecule B). Atom labels included for Ti, DMSO S and O atoms, and for C atoms with the largest modulation. 50% probability ellipsoids.

3. Supra­molecular features

The most prominent directional inter­actions in complex 3 are medium strength C—H⋯O inter­actions, involving the DMSO methyl groups as hydrogen-bond donors, and catecholate and DMSO oxygen atoms as the respective acceptors. Hydrogen bonds with C⋯O distances below 3.50 Å are given in Table 2[link]. Some of these H⋯O distances are unusually short for C—H⋯O inter­actions, with H⋯O distances as short as 2.27 and 2.34 Å, approaching distances usually only observed for classical hydrogen bonds involving acidic hydrogens. This might indicate stronger than usual inter­actions with a possibly larger influence on the packing and mol­ecular arrangement in the solid state than usually observed for C—H⋯O inter­actions.

Table 2
Hydrogen-bond geometry (Å, °)

D—H⋯A D—H H⋯A DA D—H⋯A
C11A—H11A⋯O2Bi 0.95 2.62 3.491 (3) 153
C13A—H13C⋯O5Aii 0.98 2.54 3.428 (3) 151
C14A—H14B⋯O1Aii 0.98 2.66 3.378 (3) 130
C14A—H14B⋯O5Aii 0.98 2.55 3.447 (3) 152
C14A—H14C⋯O4Biii 0.98 2.27 3.193 (3) 156
C13B—H13E⋯O5Bi 0.98 2.60 3.495 (4) 151
C14B—H14E⋯O4Ai 0.98 2.55 3.438 (3) 151
C14B—H14F⋯O1Bi 0.98 2.56 3.336 (3) 136
C15B—H15D⋯O3Aiv 0.98 2.34 3.307 (3) 171
C16B—H16D⋯O1Aiv 0.98 2.59 3.186 (3) 119
C16B—H16E⋯O4Ai 0.98 2.45 3.427 (3) 173
Symmetry codes: (i) [-x+1, -y+1, -z+1]; (ii) [-x, -y+2, -z+1]; (iii) [-x, -y+1, -z+1]; (iv) [x, y-1, z].

When plotting the C—H⋯O hydrogen bonds (Fig. 7[link]), it becomes evident that the inter­actions are different for the two mol­ecules, despite their close relationship by a pseudo-glide operation. Inter­actions involving the less modulated fragments of 3A and 3B exhibit similar hydrogen-bonding environments. C13 and C14 of the less-modulated DMSO mol­ecule exhibit the same type of hydrogen bonds to O1, O4 and O5 in neighboring mol­ecules (see Table 2[link] for symmetry operators and numerical values). The exact bond lengths for C14 vary slightly, a bond to O5 is broken and one to O4 significantly elongated for mol­ecule B, but the overall hydrogen-bonding pattern for this DMSO fragment is very similar for both mol­ecules A and B. This is not the case for the other significantly modulated DMSO mol­ecule. For 3B, three significant C—H⋯O inter­actions are observed, towards O1A, O3A and O4A of neighboring entities. None of these are found for 3A. All hydrogen-to-oxygen distances are beyond what could be still regarded as attractive and stabilizing. Methyl carbon atom C16A is at a distance of 3.128 Å from O1B, close enough for a C—H⋯O hydrogen bond to be suspected, but its hydrogen atoms are rotated such that the H⋯O distances are > 2.8 Å, and the C—H⋯O angles are unfavorable at 97.9 and 99.5° (H-atom positions were clearly resolved in difference-density maps and were allowed to rotate to fit the experimental electron density). The shortest distance involving the H atoms of C16A is instead towards C1B of a neighboring catecholate ring (2.734 Å, shown as a green dashed line in Fig. 7[link]), and C15A does not exhibit any H⋯X contacts < 2.8 Å. This clear difference between the hydrogen-bonding inter­actions of C15 and C16 in the two mol­ecules is clearly related to the modulation that breaks the exact Pbca glide symmetry in the structure of 3. It is not clear whether the ability to form stronger inter­actions is the cause for the modulation, or whether the modulation causes the differences in inter­molecular inter­actions and the modulation itself is caused by other less-directional forces such as dispersive inter­actions. Most likely the concerted effects of both modulation and inter­molecular inter­actions reinforcing and stabilizing each other lead to the observed packing of the mol­ecules.

[Figure 7]
Figure 7
Directional inter­actions in 3, viewed down the c axis. Red: mol­ecule A, blue: mol­ecule B. Lighter colored mol­ecules are generated by crystal symmetry. Dark-blue dashed lines: C—H⋯O bonds with H⋯O distance < 2.5 Å; light-blue dashed lines: C—H⋯O bonds with H⋯O distance between 2.5 and 2.62 A; green dashed lines C—H⋯π contacts. 50% probability ellipsoids.

4. Database survey

A database survey of titanium catecholate complexes reveals a plethora of homoleptic tris­catecholates but only a few in monometallic assemblies. A search of the Cambridge Structural Database (CSD, Version 5.42, accessed Feb 2021; Groom et al., 2016[Groom, C. R., Bruno, I. J., Lightfoot, M. P. & Ward, S. C. (2016). Acta Cryst. B72, 171-179.]) yields, in addition to 2Et3NH (Borgias et al., 1984[Borgias, B. A., Cooper, S. R., Koh, Y. B. & Raymond, K. N. (1984). Inorg. Chem. 23, 1009-1016.]), eleven other monocationic homoleptic tris­catecholate titanium complexes with only one metal center: SUKNUK (Kwamen et al., 2020[Kwamen, A. C. N., Schlottmann, M., Van Craen, D., Isaak, E., Baums, J., Shen, L., Massomi, A., Räuber, C., Joseph, B. P., Raabe, G., Göb, C., Oppel, I. M., Puttreddy, R., Ward, J. S., Rissanen, K., Fröhlich, R. & Albrecht, M. (2020). Chem. Eur. J. 26, 1396-1405.]), SUKQAT (Kwamen et al., 2020[Kwamen, A. C. N., Schlottmann, M., Van Craen, D., Isaak, E., Baums, J., Shen, L., Massomi, A., Räuber, C., Joseph, B. P., Raabe, G., Göb, C., Oppel, I. M., Puttreddy, R., Ward, J. S., Rissanen, K., Fröhlich, R. & Albrecht, M. (2020). Chem. Eur. J. 26, 1396-1405.]), GOJMIC (Tinoco et al., 2008[Tinoco, A. D., Eames, E. V., Incarvito, C. D. & Valentine, A. M. (2008). Inorg. Chem. 47, 8380-8390.]), LEXQUD (Dong et al., 2018[Dong, G.-L., Wang, L., Fang, W.-H. & Zhang, L. (2018). Inorg. Chem. Commun. 93, 61-64.]), LEXRAK (Dong et al., 2018[Dong, G.-L., Wang, L., Fang, W.-H. & Zhang, L. (2018). Inorg. Chem. Commun. 93, 61-64.]), MAGLAK (Van Craen et al., 2016[Van Craen, D., Albrecht, M., Raabe, G., Pan, F. & Rissanen, K. (2016). Chem. Eur. J. 22, 3255-3258.]), VEPJUW (Davis et al., 2006[Davis, A. V., Firman, T. K., Hay, B. P. & Raymond, K. N. (2006). J. Am. Chem. Soc. 128, 9484-9496.]), VEPKAD (Davis et al., 2006[Davis, A. V., Firman, T. K., Hay, B. P. & Raymond, K. N. (2006). J. Am. Chem. Soc. 128, 9484-9496.]), VILXIX (Hahn et al., 1991[Hahn, F. E., Rupprecht, S. & Moock, K. H. (1991). J. Chem. Soc. Chem. Commun. pp. 224-225.]), XIKLOV (Chen et al., 2018[Chen, X., Gerger, T. M., Räuber, C., Raabe, G., Göb, C., Oppel, I. M. & Albrecht, M. (2018). Angew. Chem. Int. Ed. 57, 11817-11820.]), and YUPNEF (Johnson et al., 2020[Johnson, S. H., Jackson, C. E. & Zadrozny, J. M. (2020). Inorg. Chem. 59, 7479-7486.]).

The conversion of tris­catecholate complexes to heteroleptic complexes has been observed previously, as the hydroxide-induced displacement of a catecholate ligand from 2Et3NH to form the bis-(μ-oxo-bridged) bis­catecholate 4 exemplifies (Borgias et al., 1984[Borgias, B. A., Cooper, S. R., Koh, Y. B. & Raymond, K. N. (1984). Inorg. Chem. 23, 1009-1016.]). Direct syntheses are also known (Sakata et al., 2010[Sakata, Y., Hiraoka, S. & Shionoya, M. (2010). Chem. Eur. J. 16, 3318-3325.]). For example, treatment of titanium methoxide with a methano­lic solution of catechol 1 under ambient conditions resulted in the formation of a dinuclear heteroleptic complex 5 with a mixture of catechol/catecholate and methanol/methano­late ligands (Bazhenova et al., 2016[Bazhenova, T. A., Kovaleva, N. V., Shilov, G. V., Petrova, G. N. & Kuznetsov, D. A. (2016). Eur. J. Inorg. Chem. pp. 5215-5221.]). Notably both examples of these heteroleptic complexes are multinuclear. Complex 5 dissolved in DMF, however, and exchanges all methanol/methano­lates for DMF and rearranges to form the mononuclear [bis­catecholate-bis-DMF]titanium complex 6, the DMF analogue of the title compound (CCDC 1489371; Bazhenova et al., 2016[Bazhenova, T. A., Kovaleva, N. V., Shilov, G. V., Petrova, G. N. & Kuznetsov, D. A. (2016). Eur. J. Inorg. Chem. pp. 5215-5221.]). Neutral and monometallic complexes of this kind are exceedingly rare. A search of the CSD yielded complex 6 as the only other heteroleptic mono-nuclear, neutral bis-catecholate complex with TiO6 metal coordination; complex 3 is only the second such complex.

5. Synthesis and crystallization

Triscatcholate 2H (500 mg, 1.34 × 10 −3 mol), prepared as described in the literature (Davies & Dutremez, 1990[Davies, J. A. & Dutremez, S. (1990). J. Am. Ceram. Soc. 73, 1429-1430.]), was dissolved at ∼173 K, in the minimal amount of DMSO (∼15 ml). The deep, dark-orange solution was allowed to cool slowly (in the water bath) to ambient temperature. The crystal mass that formed was broken up, placed on a porcelain frit, washed with minimal amount of cool DMSO (m.p. 292 K!), then cold diethyl ether, and dried under suction. The red–orange matted plates of 3 (320 mg, 0.76 × 10 −3 mol, 57% yield) were analytically pure. By NMR spectroscopy (cf. Fig. 3[link]B), the reaction is qu­anti­tative; nonetheless, no attempt was made to increase the yield by recovery of more product from the filtrate. C16H20O6S2Ti (MW = 420.32 g mol−1); 1H NMR (400 MHz, DMSO-d6): δ 6.45 (m, 2H, 4,5-CH), 6.13 (m, 2H, 3,6-CH), 2.31 (s, 3H, CH3) ppm; UV–vis (DMSO): λmax (ɛ/M−1 cm−1) = 280 (9000), 343 (2000), 441 (2500).

6. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 3[link]. The structure exhibits pseudo-ortho­rhom­bic symmetry (Pbca) and is twinned by a 180° rotation around the a- or c-axis. Application of the transformation matrix 1 0 0, 0 − 1 0, 0 0 − 1 yielded a twin ratio of 0.5399 (7):0.4401 (7). The pseudo-ortho­rhom­bic symmetry is broken by modulation of one of the catecholate rings by up to 1.4 Å, and one of the DMSO ligands by over 1.7 Å.

Table 3
Experimental details

Crystal data
Chemical formula [Ti(C6H4O2)2(C2H6OS)2]
Mr 420.34
Crystal system, space group Monoclinic, P21/c
Temperature (K) 100
a, b, c (Å) 12.4531 (3), 14.7287 (3), 20.3676 (5)
β (°) 90.0445 (9)
V3) 3735.78 (15)
Z 8
Radiation type Mo Kα
μ (mm−1) 0.71
Crystal size (mm) 0.35 × 0.23 × 0.09
 
Data collection
Diffractometer Nonius Kappa CCD
Absorption correction Multi-scan (SCALEPACK; Otwinowski & Minor, 1997[Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307-326. New York: Academic Press.])
Tmin, Tmax 0.668, 0.939
No. of measured, independent and observed [I > 2σ(I)] reflections 39962, 8552, 7393
Rint 0.047
(sin θ/λ)max−1) 0.666
 
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.036, 0.073, 1.04
No. of reflections 8552
No. of parameters 461
H-atom treatment H-atom parameters constrained
Δρmax, Δρmin (e Å−3) 0.41, −0.45
Computer programs: COLLECT (Nonius, 1998[Nonius (1998). COLLECT. Nonius BV, Delft, The Netherlands.]), HKL-3000 (Otwinowski & Minor, 1997[Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307-326. New York: Academic Press.]), SHELXS97 (Sheldrick, 2008[Sheldrick, G. M. (2008). Acta Cryst. A64, 112-122.]), SHELXL2018/3 (Sheldrick, 2015[Sheldrick, G. M. (2015). Acta Cryst. C71, 3-8.]), ShelXle (Hübschle et al., 2011[Hübschle, C. B., Sheldrick, G. M. & Dittrich, B. (2011). J. Appl. Cryst. 44, 1281-1284.]), Mercury (Macrae et al., 2020[Macrae, C. F., Sovago, I., Cottrell, S. J., Galek, P. T. A., McCabe, P., Pidcock, E., Platings, M., Shields, G. P., Stevens, J. S., Towler, M. & Wood, P. A. (2020). J. Appl. Cryst. 53, 226-235.]), and publCIF (Westrip, 2010[Westrip, S. P. (2010). J. Appl. Cryst. 43, 920-925.]).

C—H bond distances were constrained to 0.95 Å for aromatic C—H and to 0.98 Å for aliphatic CH3 moieties, respectively. Uiso(H) values were set to a multiple of Ueq(C) with 1.5 for CH3 and 1.2 for C—H units. Reflections [\overline{1}]12, 112 and 013 were affected by the beam stop and were omitted from the refinement.

Supporting information


Computing details top

Data collection: COLLECT (Nonius, 1998); cell refinement: HKL-3000 (Otwinowski & Minor, 1997); data reduction: HKL-3000 (Otwinowski & Minor, 1997); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL2018/3 (Sheldrick, 2015), ShelXle (Hübschle et al., 2011); molecular graphics: Mercury (Macrae et al., 2020); software used to prepare material for publication: publCIF (Westrip, 2010).

Bis(benzene-1,2-diolato-κ2O,O')bis(dimethyl sulfoxide-κO)titanium(IV) top
Crystal data top
[Ti(C6H4O2)2(C2H6OS)2]F(000) = 1744
Mr = 420.34Dx = 1.495 Mg m3
Monoclinic, P21/cMo Kα radiation, λ = 0.71073 Å
a = 12.4531 (3) ÅCell parameters from 39962 reflections
b = 14.7287 (3) Åθ = 1.4–28.3°
c = 20.3676 (5) ŵ = 0.71 mm1
β = 90.0445 (9)°T = 100 K
V = 3735.78 (15) Å3Plate, orange
Z = 80.35 × 0.23 × 0.09 mm
Data collection top
Nonius Kappa CCD
diffractometer
8552 independent reflections
Radiation source: fine focus X-ray tube7393 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.047
ω and φ scansθmax = 28.3°, θmin = 1.4°
Absorption correction: multi-scan
(SCALEPACK; Otwinowski & Minor, 1997)
h = 1614
Tmin = 0.668, Tmax = 0.939k = 1918
39962 measured reflectionsl = 2527
Refinement top
Refinement on F2Secondary atom site location: difference Fourier map
Least-squares matrix: fullHydrogen site location: inferred from neighbouring sites
R[F2 > 2σ(F2)] = 0.036H-atom parameters constrained
wR(F2) = 0.073 w = 1/[σ2(Fo2) + (0.0246P)2 + 2.3086P]
where P = (Fo2 + 2Fc2)/3
S = 1.04(Δ/σ)max = 0.001
8552 reflectionsΔρmax = 0.41 e Å3
461 parametersΔρmin = 0.45 e Å3
0 restraintsExtinction correction: SHELXL2018/3 (Sheldrick 2015), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
Primary atom site location: structure-invariant direct methodsExtinction coefficient: 0.00192 (16)
Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Refinement. The structure exhibits pseudo-orthorhombic symmetry (Pbca) and is twinned by a 180 degree rotation around the a or c-axis. Application of the twin matrix 1 0 0, 0 -1 0, 0 0 -1 yielded a twin ratio of 0.5399 (7) to 0.4401 (7). The pseudo-orthorhombic symmetry is broken by modulation of the phenylene rings by up to 1.4 Angstrom.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/Ueq
Ti1A0.23792 (4)0.86347 (3)0.47159 (2)0.01639 (11)
S1A0.01041 (6)0.90084 (4)0.40944 (3)0.01861 (14)
S2A0.17900 (6)0.65300 (4)0.43411 (4)0.02237 (15)
O1A0.29396 (14)0.97324 (11)0.50941 (9)0.0181 (4)
O2A0.23951 (14)0.82784 (11)0.56301 (8)0.0186 (4)
O3A0.24928 (15)0.89650 (11)0.37882 (9)0.0199 (4)
O4A0.36941 (15)0.80282 (12)0.45119 (9)0.0196 (4)
O5A0.09197 (14)0.92578 (12)0.46412 (9)0.0193 (4)
O6A0.14803 (15)0.75007 (12)0.45420 (9)0.0220 (4)
C1A0.3082 (2)0.97271 (16)0.57562 (13)0.0171 (5)
C2A0.3488 (2)1.04342 (17)0.61292 (13)0.0208 (5)
H2A0.3680911.0992810.5928230.025*
C3A0.3608 (2)1.03143 (19)0.68025 (14)0.0278 (6)
H3A0.3884671.0796140.7062680.033*
C4A0.3331 (3)0.9502 (2)0.70978 (15)0.0293 (7)
H4A0.3421270.9431140.7558210.035*
C5A0.2919 (2)0.87832 (18)0.67256 (14)0.0246 (6)
H5A0.2730060.8225310.6929090.030*
C6A0.2790 (2)0.89005 (17)0.60499 (13)0.0169 (5)
C7A0.3287 (2)0.85289 (16)0.34636 (13)0.0186 (5)
C8A0.3427 (2)0.85377 (18)0.27873 (13)0.0249 (6)
H8A0.2963150.8878240.2510480.030*
C9A0.4274 (2)0.80286 (19)0.25277 (14)0.0270 (6)
H9A0.4378370.8014840.2065880.032*
C10A0.4962 (2)0.75445 (18)0.29301 (14)0.0269 (6)
H10A0.5538160.7213260.2740720.032*
C11A0.4823 (2)0.75350 (17)0.36086 (14)0.0230 (6)
H11A0.5303300.7212730.3885970.028*
C12A0.3960 (2)0.80109 (17)0.38657 (13)0.0179 (5)
C13A0.0307 (2)1.00875 (18)0.37881 (14)0.0231 (6)
H13A0.0942761.0012300.3509830.035*
H13B0.0276601.0354340.3529350.035*
H13C0.0479551.0489110.4156780.035*
C14A0.1055 (2)0.86991 (17)0.45376 (14)0.0219 (6)
H14A0.1654630.8610170.4232320.033*
H14B0.1235870.9181740.4849750.033*
H14C0.0919250.8133510.4777090.033*
C15A0.1571 (3)0.6507 (2)0.34776 (16)0.0470 (10)
H15A0.1647350.5882850.3316800.070*
H15B0.2098480.6897150.3259750.070*
H15C0.0844930.6726880.3380690.070*
C16A0.0645 (2)0.58991 (18)0.45798 (15)0.0267 (6)
H16A0.0696750.5281440.4403850.040*
H16B0.0003130.6192700.4407750.040*
H16C0.0606920.5874060.5060080.040*
Ti1B0.26978 (4)0.36710 (3)0.47110 (2)0.01648 (10)
S1B0.48538 (6)0.41289 (4)0.39989 (3)0.01951 (14)
S2B0.32921 (5)0.15962 (4)0.44898 (3)0.01756 (14)
O1B0.22436 (15)0.46008 (11)0.53031 (9)0.0204 (4)
O2B0.28384 (14)0.30116 (11)0.55326 (9)0.0195 (4)
O3B0.22962 (15)0.41888 (11)0.38620 (9)0.0190 (4)
O4B0.13334 (14)0.30782 (12)0.45810 (9)0.0193 (4)
O5B0.41145 (15)0.43189 (12)0.45889 (9)0.0213 (4)
O6B0.35320 (15)0.26045 (11)0.43304 (9)0.0197 (4)
C1B0.2044 (2)0.43151 (18)0.59244 (13)0.0190 (5)
C2B0.1564 (2)0.48346 (19)0.64125 (14)0.0252 (6)
H2B0.1371990.5449490.6334820.030*
C3B0.1374 (3)0.4429 (2)0.70182 (15)0.0318 (7)
H3B0.1052390.4773130.7360010.038*
C4B0.1645 (2)0.3529 (2)0.71306 (14)0.0306 (7)
H4B0.1484610.3259890.7542840.037*
C5B0.2149 (2)0.30157 (19)0.66489 (13)0.0264 (6)
H5B0.2351550.2404460.6731910.032*
C6B0.2353 (2)0.34154 (17)0.60413 (13)0.0201 (5)
C7B0.1430 (2)0.38045 (16)0.35732 (13)0.0189 (6)
C8B0.1074 (2)0.39564 (18)0.29362 (14)0.0248 (6)
H8B0.1450050.4358480.2653150.030*
C9B0.0150 (3)0.35044 (19)0.27199 (14)0.0295 (6)
H9B0.0097380.3600430.2284060.035*
C10B0.0408 (2)0.29247 (18)0.31242 (14)0.0256 (6)
H10B0.1037310.2632720.2966790.031*
C11B0.0054 (2)0.27610 (17)0.37675 (13)0.0221 (6)
H11B0.0439140.2364150.4049580.027*
C12B0.0873 (2)0.31931 (17)0.39817 (13)0.0176 (5)
C13B0.5285 (3)0.52345 (18)0.37659 (15)0.0271 (7)
H13D0.5841700.5185130.3427800.041*
H13E0.5577990.5550090.4149970.041*
H13F0.4673740.5577250.3591590.041*
C14B0.6051 (2)0.37109 (19)0.43729 (16)0.0274 (7)
H14D0.6597870.3611180.4035030.041*
H14E0.5896890.3136470.4596690.041*
H14F0.6314840.4155380.4692580.041*
C15B0.2614 (2)0.12076 (17)0.37805 (14)0.0271 (6)
H15D0.2502410.0550540.3812480.041*
H15E0.3047020.1343220.3390950.041*
H15F0.1918090.1513790.3744970.041*
C16B0.4557 (2)0.10696 (18)0.43641 (15)0.0243 (6)
H16D0.4474540.0408890.4390050.036*
H16E0.5061560.1273500.4702770.036*
H16F0.4833040.1235670.3929940.036*
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Ti1A0.0163 (3)0.0142 (2)0.0187 (2)0.00011 (18)0.0001 (2)0.00122 (16)
S1A0.0179 (3)0.0183 (3)0.0196 (3)0.0017 (2)0.0006 (3)0.0031 (2)
S2A0.0197 (4)0.0154 (3)0.0319 (4)0.0009 (2)0.0018 (3)0.0002 (3)
O1A0.0205 (10)0.0161 (9)0.0175 (9)0.0006 (7)0.0004 (7)0.0008 (7)
O2A0.0190 (10)0.0166 (8)0.0203 (9)0.0029 (7)0.0006 (8)0.0004 (7)
O3A0.0197 (10)0.0204 (9)0.0197 (9)0.0040 (7)0.0002 (8)0.0006 (7)
O4A0.0210 (10)0.0191 (9)0.0188 (9)0.0022 (7)0.0007 (8)0.0000 (7)
O5A0.0159 (10)0.0202 (9)0.0218 (10)0.0022 (7)0.0018 (8)0.0061 (8)
O6A0.0213 (10)0.0171 (9)0.0276 (10)0.0012 (7)0.0001 (8)0.0050 (7)
C1A0.0117 (13)0.0177 (12)0.0219 (13)0.0041 (9)0.0000 (10)0.0002 (10)
C2A0.0173 (14)0.0182 (12)0.0271 (14)0.0019 (10)0.0020 (11)0.0010 (10)
C3A0.0283 (16)0.0273 (14)0.0278 (15)0.0022 (11)0.0078 (13)0.0059 (12)
C4A0.0307 (18)0.0382 (17)0.0190 (14)0.0020 (13)0.0057 (12)0.0028 (12)
C5A0.0209 (15)0.0271 (14)0.0258 (15)0.0015 (11)0.0005 (12)0.0052 (11)
C6A0.0117 (13)0.0180 (12)0.0210 (13)0.0007 (10)0.0013 (10)0.0019 (10)
C7A0.0184 (15)0.0159 (12)0.0216 (13)0.0028 (10)0.0029 (11)0.0005 (10)
C8A0.0292 (17)0.0238 (14)0.0217 (14)0.0046 (11)0.0008 (12)0.0023 (11)
C9A0.0316 (17)0.0285 (15)0.0209 (15)0.0051 (12)0.0087 (12)0.0040 (11)
C10A0.0252 (15)0.0231 (13)0.0323 (16)0.0037 (12)0.0075 (13)0.0041 (12)
C11A0.0191 (15)0.0178 (13)0.0322 (15)0.0003 (11)0.0035 (12)0.0019 (11)
C12A0.0177 (14)0.0158 (12)0.0203 (14)0.0032 (10)0.0017 (11)0.0010 (10)
C13A0.0253 (16)0.0236 (14)0.0205 (15)0.0002 (11)0.0004 (12)0.0046 (11)
C14A0.0199 (14)0.0179 (13)0.0280 (15)0.0000 (10)0.0008 (12)0.0013 (11)
C15A0.076 (3)0.0343 (18)0.0308 (18)0.0207 (17)0.0158 (18)0.0095 (14)
C16A0.0244 (15)0.0186 (13)0.0372 (17)0.0038 (11)0.0053 (13)0.0019 (12)
Ti1B0.0168 (2)0.0141 (2)0.0185 (2)0.00012 (18)0.0016 (2)0.00020 (17)
S1B0.0187 (3)0.0180 (3)0.0219 (3)0.0023 (3)0.0019 (3)0.0018 (2)
S2B0.0156 (3)0.0140 (3)0.0231 (3)0.0003 (2)0.0016 (3)0.0003 (2)
O1B0.0216 (10)0.0173 (8)0.0224 (10)0.0025 (7)0.0018 (8)0.0000 (7)
O2B0.0204 (10)0.0179 (9)0.0202 (10)0.0010 (7)0.0002 (8)0.0007 (7)
O3B0.0204 (10)0.0174 (8)0.0193 (9)0.0031 (7)0.0009 (8)0.0014 (7)
O4B0.0191 (10)0.0207 (9)0.0180 (9)0.0003 (7)0.0006 (8)0.0037 (7)
O5B0.0206 (10)0.0208 (10)0.0226 (10)0.0010 (7)0.0055 (9)0.0047 (8)
O6B0.0205 (10)0.0131 (8)0.0256 (10)0.0024 (7)0.0059 (8)0.0012 (7)
C1B0.0168 (14)0.0219 (13)0.0182 (13)0.0019 (10)0.0028 (10)0.0037 (10)
C2B0.0211 (15)0.0256 (14)0.0289 (15)0.0000 (11)0.0003 (12)0.0067 (11)
C3B0.0296 (18)0.0444 (18)0.0215 (15)0.0053 (14)0.0052 (13)0.0102 (13)
C4B0.0297 (17)0.0444 (18)0.0176 (14)0.0072 (13)0.0008 (12)0.0036 (12)
C5B0.0285 (16)0.0293 (15)0.0213 (14)0.0049 (11)0.0020 (12)0.0026 (11)
C6B0.0149 (13)0.0254 (13)0.0201 (13)0.0024 (10)0.0019 (11)0.0056 (11)
C7B0.0215 (15)0.0143 (12)0.0210 (13)0.0007 (10)0.0011 (11)0.0016 (10)
C8B0.0335 (17)0.0217 (14)0.0190 (14)0.0026 (11)0.0032 (12)0.0034 (11)
C9B0.0386 (18)0.0305 (15)0.0195 (14)0.0009 (13)0.0054 (13)0.0029 (11)
C10B0.0247 (16)0.0260 (14)0.0260 (15)0.0037 (11)0.0055 (12)0.0025 (11)
C11B0.0211 (15)0.0200 (13)0.0252 (14)0.0020 (10)0.0023 (12)0.0002 (10)
C12B0.0197 (14)0.0164 (12)0.0166 (13)0.0030 (10)0.0014 (11)0.0005 (10)
C13B0.0288 (17)0.0234 (14)0.0290 (16)0.0050 (12)0.0016 (13)0.0069 (12)
C14B0.0231 (16)0.0247 (15)0.0344 (17)0.0028 (11)0.0018 (13)0.0019 (13)
C15B0.0273 (16)0.0194 (13)0.0347 (16)0.0006 (11)0.0076 (13)0.0025 (11)
C16B0.0190 (15)0.0219 (13)0.0320 (16)0.0024 (10)0.0016 (12)0.0026 (11)
Geometric parameters (Å, º) top
Ti1A—O4A1.9113 (19)Ti1B—O1B1.9108 (18)
Ti1A—O1A1.9220 (17)Ti1B—O4B1.9284 (19)
Ti1A—O2A1.9346 (18)Ti1B—O2B1.9427 (18)
Ti1A—O3A1.9564 (18)Ti1B—O3B1.9545 (18)
Ti1A—O6A2.0414 (18)Ti1B—O5B2.0214 (19)
Ti1A—O5A2.0416 (18)Ti1B—O6B2.0367 (17)
S1A—O5A1.5509 (19)S1B—O5B1.5400 (19)
S1A—C14A1.763 (3)S1B—C13B1.779 (3)
S1A—C13A1.782 (3)S1B—C14B1.783 (3)
S2A—O6A1.5364 (19)S2B—O6B1.5494 (18)
S2A—C16A1.771 (3)S2B—C15B1.768 (3)
S2A—C15A1.780 (3)S2B—C16B1.774 (3)
O1A—C1A1.360 (3)O1B—C1B1.357 (3)
O2A—C6A1.346 (3)O2B—C6B1.339 (3)
O3A—C7A1.352 (3)O3B—C7B1.353 (3)
O4A—C12A1.358 (3)O4B—C12B1.359 (3)
C1A—C2A1.384 (4)C1B—C2B1.390 (4)
C1A—C6A1.404 (3)C1B—C6B1.400 (4)
C2A—C3A1.391 (4)C2B—C3B1.392 (4)
C2A—H2A0.9500C2B—H2B0.9500
C3A—C4A1.383 (4)C3B—C4B1.387 (4)
C3A—H3A0.9500C3B—H3B0.9500
C4A—C5A1.399 (4)C4B—C5B1.389 (4)
C4A—H4A0.9500C4B—H4B0.9500
C5A—C6A1.396 (4)C5B—C6B1.394 (4)
C5A—H5A0.9500C5B—H5B0.9500
C7A—C8A1.389 (4)C7B—C8B1.389 (4)
C7A—C12A1.398 (4)C7B—C12B1.409 (4)
C8A—C9A1.398 (4)C8B—C9B1.401 (4)
C8A—H8A0.9500C8B—H8B0.9500
C9A—C10A1.383 (4)C9B—C10B1.375 (4)
C9A—H9A0.9500C9B—H9B0.9500
C10A—C11A1.393 (4)C10B—C11B1.403 (4)
C10A—H10A0.9500C10B—H10B0.9500
C11A—C12A1.385 (4)C11B—C12B1.388 (4)
C11A—H11A0.9500C11B—H11B0.9500
C13A—H13A0.9800C13B—H13D0.9800
C13A—H13B0.9800C13B—H13E0.9800
C13A—H13C0.9800C13B—H13F0.9800
C14A—H14A0.9800C14B—H14D0.9800
C14A—H14B0.9800C14B—H14E0.9800
C14A—H14C0.9800C14B—H14F0.9800
C15A—H15A0.9800C15B—H15D0.9800
C15A—H15B0.9800C15B—H15E0.9800
C15A—H15C0.9800C15B—H15F0.9800
C16A—H16A0.9800C16B—H16D0.9800
C16A—H16B0.9800C16B—H16E0.9800
C16A—H16C0.9800C16B—H16F0.9800
O4A—Ti1A—O1A99.75 (8)O1B—Ti1B—O4B98.62 (8)
O4A—Ti1A—O2A94.27 (8)O1B—Ti1B—O2B80.85 (8)
O1A—Ti1A—O2A80.73 (7)O4B—Ti1B—O2B88.32 (8)
O4A—Ti1A—O3A81.00 (8)O1B—Ti1B—O3B101.72 (8)
O1A—Ti1A—O3A98.71 (8)O4B—Ti1B—O3B80.24 (8)
O2A—Ti1A—O3A175.09 (8)O2B—Ti1B—O3B168.52 (8)
O4A—Ti1A—O6A92.85 (8)O1B—Ti1B—O5B89.89 (8)
O1A—Ti1A—O6A163.08 (8)O4B—Ti1B—O5B165.00 (8)
O2A—Ti1A—O6A87.15 (7)O2B—Ti1B—O5B105.30 (8)
O3A—Ti1A—O6A94.35 (8)O3B—Ti1B—O5B85.97 (8)
O4A—Ti1A—O5A163.07 (8)O1B—Ti1B—O6B160.77 (8)
O1A—Ti1A—O5A88.55 (7)O4B—Ti1B—O6B92.76 (8)
O2A—Ti1A—O5A101.66 (8)O2B—Ti1B—O6B84.07 (7)
O3A—Ti1A—O5A83.18 (8)O3B—Ti1B—O6B95.42 (8)
O6A—Ti1A—O5A82.35 (7)O5B—Ti1B—O6B82.64 (7)
O5A—S1A—C14A103.27 (12)O5B—S1B—C13B102.87 (13)
O5A—S1A—C13A103.16 (12)O5B—S1B—C14B103.27 (13)
C14A—S1A—C13A100.06 (13)C13B—S1B—C14B100.22 (14)
O6A—S2A—C16A102.29 (12)O6B—S2B—C15B103.36 (12)
O6A—S2A—C15A104.06 (14)O6B—S2B—C16B102.56 (12)
C16A—S2A—C15A97.94 (16)C15B—S2B—C16B99.43 (14)
C1A—O1A—Ti1A116.08 (15)C1B—O1B—Ti1B114.90 (15)
C6A—O2A—Ti1A115.48 (15)C6B—O2B—Ti1B113.83 (15)
C7A—O3A—Ti1A114.05 (15)C7B—O3B—Ti1B115.14 (15)
C12A—O4A—Ti1A115.43 (16)C12B—O4B—Ti1B115.97 (16)
S1A—O5A—Ti1A121.98 (10)S1B—O5B—Ti1B122.18 (11)
S2A—O6A—Ti1A132.05 (11)S2B—O6B—Ti1B124.13 (11)
O1A—C1A—C2A125.9 (2)O1B—C1B—C2B125.1 (2)
O1A—C1A—C6A113.2 (2)O1B—C1B—C6B113.7 (2)
C2A—C1A—C6A120.8 (2)C2B—C1B—C6B121.2 (2)
C1A—C2A—C3A119.0 (2)C1B—C2B—C3B118.1 (3)
C1A—C2A—H2A120.5C1B—C2B—H2B120.9
C3A—C2A—H2A120.5C3B—C2B—H2B120.9
C4A—C3A—C2A120.8 (3)C4B—C3B—C2B121.0 (3)
C4A—C3A—H3A119.6C4B—C3B—H3B119.5
C2A—C3A—H3A119.6C2B—C3B—H3B119.5
C3A—C4A—C5A120.7 (3)C3B—C4B—C5B120.9 (3)
C3A—C4A—H4A119.7C3B—C4B—H4B119.5
C5A—C4A—H4A119.7C5B—C4B—H4B119.5
C6A—C5A—C4A118.8 (3)C4B—C5B—C6B118.7 (3)
C6A—C5A—H5A120.6C4B—C5B—H5B120.7
C4A—C5A—H5A120.6C6B—C5B—H5B120.7
O2A—C6A—C5A125.7 (2)O2B—C6B—C5B125.6 (2)
O2A—C6A—C1A114.5 (2)O2B—C6B—C1B114.4 (2)
C5A—C6A—C1A119.9 (2)C5B—C6B—C1B120.0 (2)
O3A—C7A—C8A125.0 (2)O3B—C7B—C8B126.3 (2)
O3A—C7A—C12A114.3 (2)O3B—C7B—C12B113.8 (2)
C8A—C7A—C12A120.7 (3)C8B—C7B—C12B119.9 (2)
C7A—C8A—C9A117.7 (3)C7B—C8B—C9B118.6 (2)
C7A—C8A—H8A121.1C7B—C8B—H8B120.7
C9A—C8A—H8A121.1C9B—C8B—H8B120.7
C10A—C9A—C8A121.3 (3)C10B—C9B—C8B121.5 (3)
C10A—C9A—H9A119.3C10B—C9B—H9B119.3
C8A—C9A—H9A119.3C8B—C9B—H9B119.3
C9A—C10A—C11A121.0 (3)C9B—C10B—C11B120.5 (3)
C9A—C10A—H10A119.5C9B—C10B—H10B119.7
C11A—C10A—H10A119.5C11B—C10B—H10B119.7
C12A—C11A—C10A117.8 (3)C12B—C11B—C10B118.4 (2)
C12A—C11A—H11A121.1C12B—C11B—H11B120.8
C10A—C11A—H11A121.1C10B—C11B—H11B120.8
O4A—C12A—C11A124.5 (2)O4B—C12B—C11B125.1 (2)
O4A—C12A—C7A114.3 (2)O4B—C12B—C7B113.8 (2)
C11A—C12A—C7A121.3 (3)C11B—C12B—C7B121.1 (2)
S1A—C13A—H13A109.5S1B—C13B—H13D109.5
S1A—C13A—H13B109.5S1B—C13B—H13E109.5
H13A—C13A—H13B109.5H13D—C13B—H13E109.5
S1A—C13A—H13C109.5S1B—C13B—H13F109.5
H13A—C13A—H13C109.5H13D—C13B—H13F109.5
H13B—C13A—H13C109.5H13E—C13B—H13F109.5
S1A—C14A—H14A109.5S1B—C14B—H14D109.5
S1A—C14A—H14B109.5S1B—C14B—H14E109.5
H14A—C14A—H14B109.5H14D—C14B—H14E109.5
S1A—C14A—H14C109.5S1B—C14B—H14F109.5
H14A—C14A—H14C109.5H14D—C14B—H14F109.5
H14B—C14A—H14C109.5H14E—C14B—H14F109.5
S2A—C15A—H15A109.5S2B—C15B—H15D109.5
S2A—C15A—H15B109.5S2B—C15B—H15E109.5
H15A—C15A—H15B109.5H15D—C15B—H15E109.5
S2A—C15A—H15C109.5S2B—C15B—H15F109.5
H15A—C15A—H15C109.5H15D—C15B—H15F109.5
H15B—C15A—H15C109.5H15E—C15B—H15F109.5
S2A—C16A—H16A109.5S2B—C16B—H16D109.5
S2A—C16A—H16B109.5S2B—C16B—H16E109.5
H16A—C16A—H16B109.5H16D—C16B—H16E109.5
S2A—C16A—H16C109.5S2B—C16B—H16F109.5
H16A—C16A—H16C109.5H16D—C16B—H16F109.5
H16B—C16A—H16C109.5H16E—C16B—H16F109.5
C14A—S1A—O5A—Ti1A123.30 (13)C13B—S1B—O5B—Ti1B137.68 (14)
C13A—S1A—O5A—Ti1A132.84 (14)C14B—S1B—O5B—Ti1B118.38 (14)
C16A—S2A—O6A—Ti1A159.79 (16)C15B—S2B—O6B—Ti1B103.47 (15)
C15A—S2A—O6A—Ti1A98.66 (19)C16B—S2B—O6B—Ti1B153.50 (14)
Ti1A—O1A—C1A—C2A179.0 (2)Ti1B—O1B—C1B—C2B170.4 (2)
Ti1A—O1A—C1A—C6A0.2 (3)Ti1B—O1B—C1B—C6B8.6 (3)
O1A—C1A—C2A—C3A178.5 (3)O1B—C1B—C2B—C3B177.3 (3)
C6A—C1A—C2A—C3A0.3 (4)C6B—C1B—C2B—C3B1.6 (4)
C1A—C2A—C3A—C4A0.1 (4)C1B—C2B—C3B—C4B0.6 (4)
C2A—C3A—C4A—C5A0.2 (5)C2B—C3B—C4B—C5B2.2 (5)
C3A—C4A—C5A—C6A0.1 (4)C3B—C4B—C5B—C6B1.7 (4)
Ti1A—O2A—C6A—C5A177.4 (2)Ti1B—O2B—C6B—C5B166.9 (2)
Ti1A—O2A—C6A—C1A2.8 (3)Ti1B—O2B—C6B—C1B13.3 (3)
C4A—C5A—C6A—O2A179.2 (3)C4B—C5B—C6B—O2B179.4 (3)
C4A—C5A—C6A—C1A0.5 (4)C4B—C5B—C6B—C1B0.4 (4)
O1A—C1A—C6A—O2A1.9 (3)O1B—C1B—C6B—O2B3.2 (3)
C2A—C1A—C6A—O2A179.2 (2)C2B—C1B—C6B—O2B177.7 (2)
O1A—C1A—C6A—C5A178.3 (2)O1B—C1B—C6B—C5B176.9 (2)
C2A—C1A—C6A—C5A0.6 (4)C2B—C1B—C6B—C5B2.1 (4)
Ti1A—O3A—C7A—C8A169.6 (2)Ti1B—O3B—C7B—C8B170.3 (2)
Ti1A—O3A—C7A—C12A7.5 (3)Ti1B—O3B—C7B—C12B9.2 (3)
O3A—C7A—C8A—C9A178.2 (2)O3B—C7B—C8B—C9B179.3 (3)
C12A—C7A—C8A—C9A1.3 (4)C12B—C7B—C8B—C9B1.2 (4)
C7A—C8A—C9A—C10A1.1 (4)C7B—C8B—C9B—C10B0.4 (4)
C8A—C9A—C10A—C11A1.1 (4)C8B—C9B—C10B—C11B0.8 (4)
C9A—C10A—C11A—C12A1.3 (4)C9B—C10B—C11B—C12B0.4 (4)
Ti1A—O4A—C12A—C11A173.6 (2)Ti1B—O4B—C12B—C11B173.9 (2)
Ti1A—O4A—C12A—C7A6.8 (3)Ti1B—O4B—C12B—C7B5.8 (3)
C10A—C11A—C12A—O4A176.7 (2)C10B—C11B—C12B—O4B177.6 (2)
C10A—C11A—C12A—C7A3.7 (4)C10B—C11B—C12B—C7B2.0 (4)
O3A—C7A—C12A—O4A0.6 (3)O3B—C7B—C12B—O4B2.3 (3)
C8A—C7A—C12A—O4A176.6 (2)C8B—C7B—C12B—O4B177.2 (2)
O3A—C7A—C12A—C11A179.0 (2)O3B—C7B—C12B—C11B178.0 (2)
C8A—C7A—C12A—C11A3.8 (4)C8B—C7B—C12B—C11B2.4 (4)
Hydrogen-bond geometry (Å, º) top
D—H···AD—HH···AD···AD—H···A
C11A—H11A···O2Bi0.952.623.491 (3)153
C13A—H13C···O5Aii0.982.543.428 (3)151
C14A—H14B···O1Aii0.982.663.378 (3)130
C14A—H14B···O5Aii0.982.553.447 (3)152
C14A—H14C···O4Biii0.982.273.193 (3)156
C13B—H13E···O5Bi0.982.603.495 (4)151
C14B—H14E···O4Ai0.982.553.438 (3)151
C14B—H14F···O1Bi0.982.563.336 (3)136
C15B—H15D···O3Aiv0.982.343.307 (3)171
C16B—H16D···O1Aiv0.982.593.186 (3)119
C16B—H16E···O4Ai0.982.453.427 (3)173
Symmetry codes: (i) x+1, y+1, z+1; (ii) x, y+2, z+1; (iii) x, y+1, z+1; (iv) x, y1, z.
Continuous shape measures (CShM's) relative to ideal reference octahedral symmetry for 2Et3NH, 3 and 6 top
StructureHexagonPentagonal pyramidOctahedronTrigonal prismJohnson pentagonal pyramid J2
2Et3NH33.77323.4821.4349.80827.215
3A32.79222.1911.49110.65526.183
3B32.83021.0071.85410.15924.952
633.66422.4671.51310.06926.511
 

Funding information

Funding for this research was provided by the National Science Foundation (grant No. CHE-1625543 to M. Zeller; grants No. CHE-1465133 and CHE-1800361 to C. Brückner).

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ISSN: 2056-9890
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