Russian Chemical Bulletin, International Edition, Vol. 62, No. 5, pp. 1262—1267, May, 20131262

Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 1262—1267, May, 2013.

1066�5285/13/6205�1262 © 2013 Springer Science+Business Media, Inc.

Photochemical arene exchange in the iron dicarbollide complex[(�9�SMe2�7,8�C2B9H10)Fe(�C6H6)]+

D. A. Loginov, M. M. Vinogradov, Z. A. Starikova, and A. R. Kudinov

A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences,28 ul. Vavilova, 119991 Moscow, Russian Federation.

Fax: +7 (499) 135 5085. E�mail: arkudinov@ineos.ac.ru

Visible light irradiation of the dicarbollide complex [(�9�SMe2�7,8�C2B9H10)Fe(�C6H6)]+

(2a) in the presence of the benzene derivatives in CH2Cl2/MeNO2 resulted in cations[(�9�SMe2�7,8�C2B9H10)Fe(�C6R6)]+ (2b—g; arene is anisole (b), toluene (c), m�xylene (d),mesitylene (e), durene (f), and hexamethylbenzene (g)) due to the arene exchange. The struc�tures of [2g]PF6 and related tricarbollide complex [(�1�ButNH�1,7,9�C3B8H10)Fe�(�C6H6)]PF6 (1) were confirmed by X�ray diffraction analysis. The nature of bonding incations 1, 2a, and [CpFe(�С6Н6)]+ was analyzed by an energy decomposition analysis.

Key words: arene complexes, iron, metallacarboranes, sandwich compounds.

Photochemical displacement of benzene in transitionmetal complexes is used for the synthesis of compounds ofdifferent types, for example, sandwich, triple�decked, andcluster. This reaction was studied in most detail for theiron cyclopentadienyl complexes [(�C5R5)Fe(�C6H6)]+

(see Refs 1—8). We have recently found the first examplesfor these transformations of the ferracarborane complex�es.9—12 For instance, the tricarbollide complex [(�1�But�NH�1,7,9�C3B8H10)Fe(�C6H6)]+ (1) exchanges benzenefor other arenes13 and the irradiation of the dicarbollidederivative [(�9�SMe2�7,8�C2B9H10)Fe(�C6H6)]+ (2a)in the presence of ButNC or P(OMe)3 results in the tris�(ligand) complexes [(�9�SMe2�7,8�C2B9H10)Fe(L)3]+

(see Refs 14 and 15). Continuing these investigations, inthe present work we studied the photochemical reactionof cation 2a with benzene derivatives.

Results and Discussion

We found that under visible light irradiation ina CH2Cl2 : MeNO2 (5 : 1) mixture cation 2a exchangesbenzene for other arenes similarly to tricarbollide complex1 (Scheme 1).** An addition of nitromethane is caused bythe low solubility of salt [2a]PF6 in pure dichloromethane.The benzene derivatives containing Me and ОМе groupswere successfully used as arenes in this reaction.

To estimate the rate of the process, we carried out thecompetitive reaction of benzene ligand exchange in cat�

ion 2a and its cyclopentadienyl analog [CpFe(�C6H6)]+

(3) for mesitylene. For complex 2a, the conversion was38% after irradiation for 15 min and it was 9% for [CpFe(�C6H6)]+. This indicates a higher reactivity of carboranederivative 2a.

Synthesized ferracarborane complexes [2b—g]PF6 areorange solids stable in air. In the 1Н NMR spectra, thesignals of the ring protons of the arene ligand exhibit anupfield shift relative to free arene (Table 1) similarly tocyclopentadienyl analogs [CpFe(�arene)]+. However, itshould be mentioned that a downfield shift is observed forrelated dicationic rhodium and iridium complexes [(�9�SMe2�7,8�C2B9H10)M(�arene)]2+.16 With an increase inthe number of methyl groups in the arene ligand in cations2a—g, the signals of the CH protons of the carborane cageexhibit an upfield shift. Interestingly, in xylene complex 2d

* Dedicated to blessed memory of P. V. Petrovskii who contrib�uted considerably to the development of organometallic chemistry.** All synthesized cationic complexes were isolated as salts withPF6

– anion (in schemes anions are omitted).

Scheme 1

2 Rn 2 Rnb OMe e 1,3,5�Me3c Me f 1,2,4,5�Me4d 1,3�Me2 g Me6

Arene exchange in ferracarborane complex Russ.Chem.Bull., Int.Ed., Vol. 62, No. 5, May, 2013 1263

the protons of the methyl groups appear as two individualsignals and the ring protons appear as four signals, whichis explained by C1 symmetry of the complex and retardedrotation of the arene ring because of the steric repulsion ofthe substituents.17 A similar pattern is observed for signalsof the methyl groups in durene complex 2f.

The structure of hexamethylbenzene complex [2g]PF6was solved by X�ray diffraction analysis (the molecularstructure of cation 2g is shown in Fig. 1, and selected bondlengths are given in Table 2). The angle between the С6and С2B3 rings is 7.2, which is likely a consequence of thesteric effect of the SMe2 group; the shortest distanceC(14)—S(1) (3.305 Å) is substantially less than the sum ofvan der Waals radii of the C and S atoms (3.94 Å). Thedistance from the iron atom to the plane of the areneligand Fe...C6 (1.623 Å) is significantly longer than that inthe cyclopentadienyl analog [CpFe(�C6Me6)]+ (1.547 Å),18

indicating a less strength of the Fe—C6Me6 bond in theferracarborane complex. The Fe...C2B3 distance in cation2g is very close to the corresponding distance in benzenederivative 2a (1.496 Å).15 It should be mentioned that theFe...C6 distance in the latter (1.586 Å) is considerablyshorter than that in the complex with hexamethylbenzenedue to the steric effect of six methyl groups.

For comparison we also determined the structure of(tricarbollide)benzene complex [1]PF6 (the molecularstructure of cation 1 is shown in Fig. 2, and selected bondlengths are given in Table 3). The pentagonal face of thecarborane ligand С2B3 is distorted and has an envelopeconformation with the deviation of the B(8) atom fromthe С(9A)B(10)B(11)C(7A) plane (the angle between the

С(7A)B(8)C(9A) and С(9A)B(10)B(11)C(7A) planes is7.6). It turned out that the Fe...C2B3 (1.483 Å) and Fe...C6(1.574 Å) distances in this complex is only insignificantlyshorter than that in cation 2a (Fe...C2B3 1.496 Å, Fe...C61.586 Å),15 indicating a close resemblance of the tri�carbollide [1�ButNH�1,7,9�C3B8H10]– and dicarbollide[9�SMe2�7,8�C2B9H10]– ligands.

The bond of the iron atom with benzene and carboraneligands in tricarbollide and dicarbollide complexes 1 and2а was studied by DFT calculations (BP86/TZ2P) basedon an energy decomposition analysis.19 The data obtainedby this method for complexes 1, 2а, and [CpFe(�С6Н6)]+

(3) using the [(L)Fe]+ + C6Н6 (Fe—С6Н6 bond) and[Fe(C6H6)]+ + [L]– (Fe—L bond) fragments are given inTable 4. It is seen from an analysis of the former interac�tion that the energy of the Fe—С6Н6 bond (Eint) indicarbollide complex 2а is only insignificantly lower(by 2 kcal mol–1) than that in tricarbollide analog 1. Theenergies of orbital interactions (Eorb) in complexes 2а

Table 1. 1Н NMR spectral parameters for cations 2а—g inacetone�d6

Cation

СH SMe2 C6HmRn* Me

2a15 4.58 (1 H), 2.78 (3 H), 6.92 (6 H) —5.42 (1 H) 2.95 (3 H)

2b 4.37 (1 H), 2.76 (3 H), 6.73 (5 H) 4.23 (3 H)5.22 (1 H) 2.92 (3 H)

2c 4.38 (1 H), 2.77 (3 H), 6.76 (5 H) 2.65 (3 H)5.25 (1 H) 2.93 (3 H)

2d 4.08 (1 H), 2.79 (3 H), 6.50 (1 H), 2.53 (3 H),5.06 (1 H) 2.93 (3 H) 6.53 (1 H), 2.65 (3 H)

6.73 (1 H),6.80 (1 H)

2e 3.96 (1 H), 2.81 (3 H), 6.43 (3 H) 2.59 (9 H)4.74 (1 H) 2.96 (3 H)

2f 3.92 (1 H), 2.82 (3 H), 6.37 (2 H) 2.49 (6 H),4.44 (1 H) 2.89 (3 H) 2.56 (6 H)

2g 3.41 (1 H), 2.75 (3 H), — 2.50 (18 H)4.48 (1 H) 2.81 (3 H)

* Proton of the benzene ring.

Fig. 1. Structure of cation 2g (thermal ellipsoids of 30% proba�bility). Hydrogen atoms are omitted.

B(1)

B(3)

B(2)

B(4)

B(5)

B(6)

B(10)

C(7)

C(12)

C(11)

C(1)

C(16)

C(6)

C(3)

C(5)C(15)

C(14)C(4)

C(13)

Fe(1)

B(11)

C(2)

C(8)

C(10)

S(1)

C(9)

B(9)

Table 2. Selected bond lengths (d) in cation 2g

Bond d/Å Bond d/Å

Fe(1)—C(1) 2.134(3) C(7)—C(8) 1.630(4)Fe(1)—C(2) 2.146(3) C(8)—B(9) 1.687(4)Fe(1)—C(3) 2.153(3) B(9)—B(10) 1.783(5)Fe(1)—C(4) 2.195(3) B(10)—B(11) 1.781(5)Fe(1)—C(5) 2.156(3) B(11)—C(7) 1.704(5)Fe(1)—C(6) 2.119(3) C(1)—C(2) 1.411(5)Fe(1)—C(7) 2.053(3) C(2)—C(3) 1.416(5)Fe(1)—C(8) 2.056(3) C(3)—C(4) 1.394(5)Fe(1)—B(9) 2.111(3) C(4)—C(5) 1.419(5)Fe(1)—B(10) 2.138(3) C(5)—C(6) 1.412(5)Fe(1)—B(11) 2.100(3) C(1)—C(6) 1.410(5)B(9)—S(1) 1.911(3)

Loginov et al.1264 Russ.Chem.Bull., Int.Ed., Vol. 62, No. 5, May, 2013

and 1 do not almost differ, and a slight increase in theenergy of electrostatic attraction (Eelstat) in 2а is exces�sively compensated by an increase in the Pauli repulsionenergy (EPauli). Interestingly, the Fe—С6Н6 bond in cat�ions 1 and 2а is substantially weaker (by 15—17 kcal mol–1)than that in cyclopentadienyl analog [CpFe(�С6Н6)]+ (3).The energy of the Fe—С6Н6 bond correlates with thechange in the distance from the iron atom to the plane ofthe benzene ligand: the stronger the bond, the shorter thedistance. The difference in dissociation energies (De) ofthe carborane and cyclopentadienyl complexes attains20—25 kcal mol–1 due to a higher preparation energy(Eprep) in the case of the carborane derivatives; this isconsistent with the higher reactivity of the carborane de�rivatives in the arene exchange reactions. It is seen froman analysis of the EelstatEorb ratio that the Fe—С6Н6bond in cations 1 and 2а is predominantly covalent(57—58%).

An analysis of the [Fe(C6H6)]+ + [L]– interactionshows that the Fe—L bond in dicarbollide complex 2a isa little stronger (by 5 kcal mol–1) than that in tricarbollideanalog 1, which is consistent with a lower strength of theFe—С6Н6 bond in cation 2а (trans�effect). Interestingly,

the Fe—L bond in complex [CpFe(�С6Н6)]+ (3) is thestrongest one in the series of studied complexes, which ismainly due to a considerable decrease in the Pauli repul�sion energy and a slight increase in the electrostatic at�traction energy. According to this, the Fe—Сp bond in thecyclopentadienyl complex is more ionic (58%) than theFe—Carb bond in carborane derivatives 1 and 2а (54%).

Fig. 2. Structure of cation 1 (thermal ellipsoids of 30% probabil�ity). Hydrogen atoms, except for the H(1) atom, are omitted.

C(10)

C(8)

C(9)

C(7)

N(1)H(1)

C(1A)

B(3)

B(2)

B(11)

B(4)

B(5)

C(9A)

B(6)

C(7A)

Fe(1)

C(4)

C(3)

C(5) C(6)

C(1)

C(2)

B(8)

Table 3. Selected bond lengths (d) in cation 1

Bond d/Å Bond d/Å

Fe(1)—C(1) 2.098(5) C(7A)—B(8) 1.705(9)Fe(1)—C(2) 2.115(6) B(8)—C(9A) 1.639(10)Fe(1)—C(3) 2.107(6) C(9A)—B(10) 1.698(11)Fe(1)—C(4) 2.104(5) B(10)—B(11) 1.811(11)Fe(1)—C(5) 2.113(6) B(11)—C(7A) 1.708(9)Fe(1)—C(6) 2.130(6) C(1)—C(2) 1.392(8)Fe(1)—C(7A) 2.065(6) C(2)—C(3) 1.403(8)Fe(1)—B(8) 2.041(8) C(3)—C(4) 1.423(8)Fe(1)—C(9A) 2.112(7) C(4)—C(5) 1.418(8)Fe(1)—B(10) 2.092(7) C(5)—C(6) 1.393(9)Fe(1)—B(11) 2.082(7) C(1)—C(6) 1.411(8)C(1A)—N(1) 1.472(9)

Table 4. Energy decomposition analysis for complexes 1, 2а, and 3 (using the [(L)Fe]+ + C6Н6 or [Fe(C6H6)]+ + [L]– fragments) atthe BP86/TZ2P//PBE/L2 levela

Fragment Complex Eint EPauli Eelstatb Eorb

b Eprep De Fe...C6H6/Å

[Fe(L)]+ + C6H6 2a –87.95 193.90 –119.91 (42.54%) –161.94 (57.46%) 12.17 –75.78 1.570c, 1.586d,15

1 –89.92 188.91 –115.71 (41.50%) –163.12 (58.50%) 10.12 –79.80 1.565c, 1.574d

3 –105.06 170.04 –107.73 (39.16%) –167.36 (60.84%) 4.88 –100.18 1.534c,1.543—1.574d,20

[Fe(C6H6)]+ + [L]– 2a –379.78 225.13 –327.29 (54.10%) –277.63 (45.90%) 12.86 –366.921 –374.85 216.69 –322.38 (54.50%) –269.15 (45.50%) 10.49 –364.363 –392.32 180.54 –330.52 (57.70%) –242.34 (42.30%) 1.31 –391.01

a The energy values are given in kcal mol–1.b The percentage contribution to the total binding interaction is given in parentheses.c DFT calculation.d X�ray diffraction data.

B(10)

Arene exchange in ferracarborane complex Russ.Chem.Bull., Int.Ed., Vol. 62, No. 5, May, 2013 1265

Thus, it is shown that cationic dicarbollide complex 2aexchanges the benzene ligand for other arenes under visi�ble light irradiation, and this complex is more reac�tive than cyclopentadienyl analog [CpFe(�C6H6)]+ (3).A close resemblance between binding of the tricarbollide[1�ButNH�1,7,9�C3B8H10]– and dicarbollide [9�SMe2�7,8�C2B9H10]– ligands with the iron atom was establishedby X�ray diffraction analysis and DFT calculations.

Experimental

The reactions were carried out under argon using anhydroussolvents prepared according to standard procedures. Proceduresassociated with isolation of products were carried out in air.Complexes [1]PF6 (see Ref. 13) and [2a]PF6 (see Ref. 15) weresynthesized using known procedures. Irradiation was conductedin a Schlenk tube with a diameter of 15 mm using a filamentlamp (power 100 W at 0 C). 1Н and 11В NMR spectra wererecorded on a Bruker Avance�400 instrument (400.13 MHz (1Н),128.38 MHz (11В)).

Arene exchange in complex [2a]PF6. Complex [2a]PF6(50 mg, 0.11 mmol) was dissolved in nitromethane (1 mL), andarene (0.2 mL of toluene, m�xylene, mesitylene, or anisole or250 mg of durene or hexamethylbenzene) and CH2Cl2 (5 mL)were added. The obtained solutions were irradiated for 3 h andevaporated to dryness in vacuo. The residue was reprecipitatedwith ether from CH2Cl2. Orange solids were obtained.

[(9�Dimethylsulfonio�7,8�dicarbollyl)(�methoxybenzene)�iron]hexafluorophosphate, [(�9�SMe2�7,8�C2B9H10)Fe(�C6H5OMe)]PF6 ([2b]PF6) (arene is anisole), the yield was21.5 mg (41%). Found (%): C, 26.29; H, 4.83; B, 19.89.C11H24B9F6FeOPS. Calculated (%): C, 26.29; H, 4.81; B, 19.36.11B{1H} NMR (acetone�d6), : –1.4 (1 B), –2.6 (1 B), –4.5(1 B), –7.4 (1 B), –8.1 (1 B), –11.7 (1 B), –19.4 (1 B), –21.3 (1 B),–24.7 (1 B).

[(9�Dimethylsulfonio�7,8�dicarbollyl)(�methylbenzene)iron]�hexafluorophosphate, [(�9�SMe2�7,8�C2B9H10)Fe(�C6H5Me)]PF6 ([2c]PF6) (arene is toluene), the yield was 22.5 mg(44%). Found (%): C, 26.96; H, 4.89; B, 20.78. C11H24B9F6FePS.Calculated (%): C, 27.16; H, 4.97; B, 20.00. 11B{1H} NMR (ac�etone�d6), : –0.7 (1 B), –2.2 (1 B), –4.1 (1 B), –7.3 (1 B), –8.2(1 B), –11.5 (1 B), –19.2 (1 B), –21.0 (1 B), –24.6 (1 B).

[(9�Dimethylsulfonio�7,8�dicarbollyl)(�1,3�dimethylbenz�ene)iron]hexafluorophosphate, [(�9�SMe2�7,8�C2B9H10)Fe�(�1,3�C6H4Me2)]PF6 ([2d]PF6) (arene is m�xylene), the yieldwas 34.5 mg (65%). Found (%): C, 28.61; H, 5.29; B, 19.89.C12H26B9F6FePS. Calculated (%): C, 28.80; H, 5.24; B, 19.44.11B{1H} NMR (acetone�d6), : –0.2 (1 B), –2.5 (1 B), –4.3(1 B), –7.4 (1 B), –8.0 (1 B), –11.5 (1 B), –19.2 (1 B), –20.9 (1 B),–24.6 (1 B).

[(9�Dimethylsulfonio�7,8�dicarbollyl)(�1,3,5�trimethylbenz�ene)iron]hexafluorophosphate, [(�9�SMe2�7,8�C2B9H10)Fe�(�1,3,5�C6H3Me3)]PF6 ([2e]PF6) (arene is mesitylene), theyield was 40 mg (74%). Found (%): C, 30.09; H, 5.48; B, 18.99.C13H28B9F6FePS. Calculated (%): C, 30.34; H, 5.48; B, 18.91.11B{1H} NMR (acetone�d6), 1.4 (1 B), –2.9 (1 B), –4.6 (1 B), –7.6(1 B), –9.2 (1 B), –11.6 (1 B), –19.0 (1 B), –20.6 (1 B), –25.0 (1 B).

[(9�Dimethylsulfonio�7,8�dicarbollyl)(�1,2,4,5�tetramethyl�benzene)iron]hexafluorophosphate, [(�9�SMe2�7,8�C2B9H10)�

Fe(�1,2,4,5�C6H2Me4)]PF6 ([2f]PF6) (arene is durene), theyield was 36.5 mg (65%). Found (%): C, 31.69; H, 5.71; B, 18.68.C14H30B9F6FePS. Calculated (%): C, 31.81; H, 5.72; B, 18.41.11B{1H} NMR (acetone�d6), : 0.9 (1 B), –3.5 (1 B), –4.4 (1 B),–6.8 (1 B), –7.3 (1 B), –11.4 (1 B), –19.1 (1 B), –21.3 (1 B),–24.6 (1 B).

[(9�Dimethylsulfonio�7,8�dicarbollyl)(�hexamethylbenz�ene)iron]hexafluorophosphate, [(�9�SMe2�7,8�C2B9H10)Fe�(�C6Me6)]PF6 ([2g]PF6) (arene is hexamethylbenzene), theyield was 36.5 mg (65%). Found (%): C, 34.29; H, 6.21; B, 18.10.C16H34B9F6FePS. Calculated (%): C, 34.53; H, 6.16; B, 17.48.11B{1H} NMR (acetone�d6), : 0.1 (1 B), –4.3 (1 B), –6.4(2 B), –7.7 (1 B), –11.7 (1 B), –19.4 (1 B), –21.3 (1 B), –25.1 (1 B).

Comparative study of arene exchange in complexes [2a]PF6and [CpFe(�C6H6)]PF6. A mixture of [2a]PF6 (31 mg,0.056 mmol) and [CpFe(�C6H6)]PF6 (19 mg, 0.056 mmol) wasdissolved in MeNO2 (0.5 mL), and mesitylene (0.2 mL) andCH2Cl2 (5 mL) were added. The obtained solution was irradiat�ed for 15 min, and the solvents were removed in vacuo. Theresidue was washed with petroleum ether and reprecipitated withether from CH2Cl2. According to the 1Н NMR spectrum, theconversion to the mesitylene complex for [2a]PF6 was 38%, andthat for [CpFe(�C6H6)]PF6 was 9%.

X�ray diffraction study of complexes [1]PF6 and [2g]PF6.Single crystals of [1]PF6 and [2g]PF6 were grown by slow diffu�sion in a bilayer system Et2O—solution of complex in CH2Cl2([1]PF6) or Me2CO ([2g]PF6). The parameters of the crystallo�graphic data and details of experiment and structure decodingand refinement are given in Table 5. The structures were solvedby a direct method, and all non�hydrogen atoms were localizedin difference electron density syntheses and refined for F2

hkl inthe anisotropic approximation. A single crystal of [2g]PF6 turnedout to be a twin, and the refinement was performed using theTWIN/BASF option (BASF = 0.55). The hydrogen atoms in thecarborane fragment were localized in difference electron densitysyntheses, and other hydrogen atoms were placed in geometri�cally calculated positions. All hydrogen atoms were refinedin the isotropic approximation in the riding model with U(H) == n•U(C), where U(C) is the equivalent temperature factor ofthe carbon atom to which the H atom is bound, n = 1.2 for СНgroup, and n = 1.5 for Ме groups. All calculations were per�formed using the SHELXTL program package.21 The atomiccoordinates, temperature factors, and full data on the geometricparameters were deposited with the Cambridge CrystallographicData Centre (CCDC 906382for [1]PF6 and CCDC 906383 for[2g]PF6).

DFT calculations. The geometry was optimized without sym�metry restrains using the Priroda 6 program,22 PBE function�al,23 scalar relativistic Hamiltonian,24 atomic basis sets of Gaus�sian functions,25 and density�fitting techniques.26 The full�elec�tron three�exponential basis set L2 with two polarization func�tions was used.27

An energy decomposition analysis was performed using theADF (2006.01) program28,29 by the Morokuma—Ziegler meth�od,30,31 according to which the interaction energy Eint can bedecomposed to three components

Eint = Eelstat + EPauli + Eorb.

Energy Eelstat is calculated at the fixed electron density dis�tribution with the geometry of the complex.

Loginov et al.1266 Russ.Chem.Bull., Int.Ed., Vol. 62, No. 5, May, 2013

Table 5. Crystallographic data and refinement parameters for compounds [1]PF6 and [2g]PF6

Parameter [1]PF6 [2g]PF6

Empirical formula C13H26B8F6FeNP C16H34B9F6FePSFW 483.65 556.60Crystal system Orthorhombic OrthorhombicSpace group P 212121 P 212121a/Å 7.3935(6) 9.0389(7)b/Å 13.9827(12) 15.9896(13)c/Å 20.1877(17) 16.9833(13)V/Å3 2087.0(3) 2454.6(3)Z 4 4dcalc/g cm–3 1.539 1.506Crystal sizes/mm 0.35×0.25×0.20 0.45×0.35×0.20Color, habitus of crysal Red, needle�like Red, needle�likeDiffractometer Bruker APEX II Bruker APEX IIRadiation Mo�K ( = 0.71073) Mo�K ( = 0.71073)/mm–1 0.852 0.816Absorption correction SADABS SADABSTemperature/K 100(2) 120(2)Scan mode 2max/deg 51.98 56.00Total number of reflections 19648 26853Number of independent reflections (Rint) 4033 (0.0602) 6490 (0.0478)R1 (for F for reflections I > 2(I)) 0.0633 (3499 reflections) 0.0438 (5234 reflections)wR2 (for F 2 for all reflections) 0.1269 0.1094Number of refined parameters 274 316Weight scheme w–1 = 2(Fo

2) + (aP)2 + bP, w–1 = 2(Fo2) + (aP)2 + bP,

where P = 1/3(Fo2 + 2Fc

2) where P = 1/3(Fo2 + 2Fc

2)a 0.0151 0.0651b 7.8500 0Goodness�of�fit 1.029 0.999F(000) 984 1144Residual electron density 0.946/–0.377 1.016/–0.349

/e Å–3, max/min

Dissociation energy De was calculated as follows:

De = –(Eint + Eprep),

where Eprep is the energy necessary for the transition of isolatedfragments from the equilibrium geometry and ground electronstate to the geometry and electron state inherent in them in theoptimized structure of the complex. The calculations were per�formed using the BP86 functional32,33 and the full�electronthree�exponential TZ2P basis set with two polarization func�tions (integration accuracy 6.0). Scalar relativistic effects weretaken into account by the zero�order regular approximation(ZORA).34 The ChemCraft program was used for molecularmodeling and visualization.35

References

1. T. P. Gill, K. R. Mann, Inorg. Chem., 1980, 19, 3007.2. T. P. Gill, K. R. Mann, Inorg. Chem., 1983, 22, 1986.3. A. R. Kudinov, M. I. Rybinskaya, Yu. T. Struchkov, A. I.

Yanovskii, P. V. Petrovskii, J. Organomet. Chem., 1987, 336, 187.4. O. J. Scherer, T. Brück, G. Wolmershäuser, Chem. Ber.,

1989, 122, 2049.

5. A. R. Kudinov, D. V. Muratov, M. I. Rybinskaya, P. V.Petrovskii, A. V. Mironov, T. V. Timofeeva, Yu. L. Slovo�khotov, Yu. T. Struchkov, J. Organomet. Chem., 1991, 414, 97.

6. A. R. Kudinov, D. A. Loginov, Z. A. Starikova, P. V. Petrov�skii, M. Corsini, P. Zanello, Eur. J. Inorg. Chem., 2002, 3018.

7. A. K. Diallo, J. Ruiz, D. Astruc, Org. Lett., 2009, 11, 2635.8. D. A. Loginov, I. D. Baravi, O. I. Artyushin, Z. A. Starikova,

P. V. Petrovskii, A. R. Kudinov, Russ. Chem. Bull. (Int. Ed.),2010, 59, 1312 [Izv. Akad. Nauk, Ser. Khim., 2010, 1282].

9. A. R. Kudinov, D. A. Loginov, Russ. Chem. Bull. (Int. Ed.),2009, 58, 600 [Izv. Akad. Nauk, Ser. Khim., 2009, 586].

10. D. A. Loginov, M. M. Vinogradov, Z. A. Starikova, P. V.Petrovskii, J. Holub, A. R. Kudinov, Collect. Czech. Chem.Commun., 2010, 75, 981.

11. M. M. Vinogradov, D. A. Loginov, Z. A. Starikova, P. V.Petrovskii, J. Holub, A. R. Kudinov, Russ. Chem. Bull.(Int. Ed.), 2010, 59, 2143 [Izv. Akad. Nauk, Ser. Khim.,2010, 2089].

12. B. Štibr, J. Organomet. Chem., 2012, 716, 1.13. D. A. Loginov, M. M. Vinogradov, Z. A. Starikova, P. V.

Petrovskii, J. Holub, A. R. Kudinov, Russ. Chem. Bull.(Int. Ed.), 2008, 57, 2294 [Izv. Akad. Nauk, Ser. Khim.,2008, 2250].

Arene exchange in ferracarborane complex Russ.Chem.Bull., Int.Ed., Vol. 62, No. 5, May, 2013 1267

14. D. A. Loginov, M. M. Vinogradov, L. S. Shul´pina, A. V.Vologzhanina, P. V. Petrovskii, A. R. Kudinov, Russ. Chem.Bull. (Int. Ed.), 2007, 56, 2118 [Izv. Akad. Nauk, Ser. Khim.,2007, 2064].

15. A. R. Kudinov, P. Zanello, R. H. Herber, D. A. Loginov,M. M. Vinogradov, A. V. Vologzhanina, Z. A. Starikova,M. Corsini, G. Giorgi, I. Nowik, Organometallics, 2010,29, 2260.

16. M. Corsini, S. Losi, E. Grigiotti, F. Rossi, P. Zanello, A. R.Kudinov, D. A. Loginov, M. M. Vinogradov, Z. A. Stari�kova, J. Solid State Electrochem., 2007, 11, 1643.

17. D. A. Loginov, D. V. Muratov, Z. A. Starikova, P. V. Petro�vskii, A. R. Kudinov, J. Organomet. Chem., 2006, 691, 3646.

18. R.�M. Lequan, M. Lequan, G. Jaouen, L. Ouahab, P. Ba�tail, J. Padiou, R. G. Sutherland, Chem. Commun., 1985, 116.

19. G. Frenking, N. Frohlich, Chem. Rev., 2000, 100, 717.20. P. Zanello, R. H. Herber, A. R. Kudinov, M. Corsini, F. F.

de Biani, I. Nowik, D. A. Loginov, M. M. Vinogradov, L. S.Shul´pina, I. A. Ivanov, A. V. Vologzhanina, J. Organomet.Chem., 2009, 694, 1161

21. SHELXTL v. 6.1, Bruker AXS Inc., Madison, Wisconsin,USA, 2005.

22. D. N. Laikov, Yu. A. Ustynyuk, Russ. Chem. Bull. (Int. Ed.),2005, 54, 820 [Izv. Akad. Nauk, Ser. Khim., 2005, 804].

Received October 18, 2012;in revised form February 11, 2013

23. J. P. Perdew, K. Burke, M. Ernzerhof, Phys. Rev. Lett., 1996,77, 3865.

24. K. G. Dyall, J. Chem. Phys., 1994, 100, 2118.25. D. N. Laikov, Chem. Phys. Lett., 2005, 416, 116.26. D. N. Laikov, Chem. Phys. Lett., 1997, 281, 151.27. E. Ya. Misochko, A. V. Akimov, V. A. Belov, D. A. Tyurin,

D. N. Laikov, J. Chem. Phys., 2007, 127, 84301.28. ADF 2006.01, SCM, Theoretical Chemistry, Vrije Univer�

siteit, Amsterdam, The Netherlands, http://www.scm.com.29. F. M. Bickelhaupt, E. J. Baerends, Rev. Comput. Chem., 2000,

15, 1.30. K. Morokuma, Chem. Phys., 1971, 55, 1236.31. T. Ziegler, A. Rauk, Theor. Chim. Acta, 1977, 46, 1.32. A. D. Becke, Phys. Rev. A, 1988, 38, 3098.33. J. P. Perdew, Phys. Rev. B, 1986, 33, 8822.34. E. van Lenthe, E. J. Baerends, J. G. Snijders, J. Chem. Phys.,

1993, 99, 4597.35. G. A. Zhurko, ChemCraft 1.6, http://www.chemcraftprog.com,

2008.