Polyhedral Rearrangements in the Complexes of Rhodium and Iridium

Article pubs.acs.org/Organometallics

Polyhedral Rearrangements in the Complexes of Rhodium and Iridium with Isomeric Carborane Anions [7,8-Me2‑X-SMe2‑7,8-nidoC2B9H8]− (X = 9 and 10) Mikhail M. Vinogradov,* Yulia V. Nelyubina, Alexander A. Pavlov, Valentin V. Novikov, Nikita V. Shvydkiy, and Alexander R. Kudinov† A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 28 ul. Vavilova, Moscow 119991 GSP-1, Russian Federation S Supporting Information *

ABSTRACT: Polyhedral rearrangement of iridacarborane 1,2Me2-3,3-(cod)-4-SMe2-3,1,2-closo-IrC2B9H8 (1) proceeds in a solution at RT and affords a product of 1,2 → 1,7 isomerization 1,8-Me2-2,2-(cod)-7-SMe2-2,1,8-closo-IrC2B9H8 (2). Rhodium derivative 1,2-Me2-3,3-(cod)-4-SMe2-3,1,2closo-RhC2B9H8 (3) is significantly more stable toward heating than iridium complex 1 and isomerizes at 110 °C by 1,2 → 1,2 and 1,2 → 1,7 reaction schemes with 1,2 → 1,2 being the predominant route forming 1,2-Me2-4,4-(cod)-8-SMe2-4,1,2closo-RhC2B9H8 (4) and 1,8-Me2-2,2-(cod)-7-SMe2-2,1,8-closoRhC2B9H8 (5). Complexes 4 and 5 were characterized by 11B{1H}−11B{1H} COSY NMR spectrometry. A mechanism of 1,2 → 1,2 isomerization of 3 to 4 was proposed on the basis of DFT calculations. Reaction of the thallium salt Tl[7,8-Me2-9-SMe2-7,8nido-C2B9H8] (CarbTl) with [Cp*RuCl]4 in THF furnishes new ruthenacarborane 1,2-Me2-3-(Cp*)-4-SMe2-3,1,2-closoRuC2B9H8 (6). Heating of 6 at 80 and 144 °C leads to the partial and complete decomposition, respectively. Interaction of CarbTl with [Cp*IrCl2]2 in the presence of TlPF6 provides two new Ir(III) complexes [1,2-Me2-3-(Cp*)-4-SMe2-3,1,2-closoIrC2B9H8]PF6 (7PF6) and 1,2-Me2-3-(Cp*)-4-SMe-3,1,2-closo-IrC2B9H8 (8) both stable upon heating in boiling tetrachloroethane (146 °C). A new 10-substituted charge-compensated carborane [7,8-Me2-10-SMe2-7,8-nido-C2B9H9] (9) was synthesized via an interaction of dicarbollide dianion [7,8-Me2-7,8-nido-C2B9H9]2− with dimethyl sulfide and acetaldehyde in acidic media. Thallium salt of 9 Tl[7,8-Me2-10-SMe2-7,8-nido-C2B9H8] (10) reacts with [(cod)IrCl]2 furnishing positional isomer of 1 with a symmetrical emplacement of SMe2 substituent complex 1,2-Me2-3,3-(cod)-8-SMe2-3,1,2-closo-IrC2B9H8 (11). Iridacarborane 11 requires elevated temperatures to undergo cage isomerization and converts upon heating at 110 °C to two new compounds 1,8Me2-2,2-(cod)-11-SMe2-2,1,8-closo-IrC2B9H8 (12) and 1,2-Me2-4,4-(cod)-9-SMe2-4,1,2-closo-IrC2B9H8 (13) as a result of 1,2 → 1,7 and 1,2 → 1,2 rearrangements respectively with 13 being the minor product. The structures of 2, 6, 7PF6, 8, 10, 12, and 13 were determined by single-crystal X-ray diffraction.

■

INTRODUCTION

The remarkable feature of the o-carborane (1,2-closoC2B10H12) is polyhedral rearrangement reaction which has been of the interest for many years since the first report of ortho- to meta-carborane transformation.8 There were proposed few mechanisms of framework rearrangements: via cubeoctahedron (DSD mechanism)9 or a nido-intermediates10 and triangle face rotation (TFR)11 process. The experimental investigations into the mechanisms of carborane rearrangement are complicated due to the harsh reaction conditions (450 °C) when the reaction occurs. In particular, o-carborane isomerizes with a scrambling not only carbon but also boron atoms.12 This fact indicates that reaction may proceed with more than one mechanism. However, coordination of metals to carboranes appears to lower the rearrangement barrier and thereby allows

Icosahedral carboranes are an interesting class of exceptionally stable boron-rich clusters that can be linked with threedimensional (3D) aromatic character of such compounds.1 Unique chemical and physical properties of carborane species, such as rigidity and high stability to air and moisture, allowed to incorporate of these molecules into a variety of materials, such as biologically active molecules,2 ceramics and polymers,3 lightemitting materials,4 and electricity sources,5 and to access a set of properties not normally available in carbon chemistry. Carboranes are useful building blocks for ligand and catalyst design in organometallic chemistry.6 Polyhedral boron clusters can exhibit both π- and σ-interaction with transition metals providing a combination of high steric hindrance and unique electronic effects with their C−M, B−M, or B−H···M coordination to a metal center.7 © XXXX American Chemical Society

Received: November 16, 2016

A

DOI: 10.1021/acs.organomet.6b00858 Organometallics XXXX, XXX, XXX−XXX

Article

Organometallics investigating cage isomerizations at RT or even at lower temperatures.13 Although numerous metallacarborane rearrangements were reported, this information has a fragmentary character that makes its systematization unavailable due to the different organometallic fragments and carborane ligands used. Herein we report the synthesis of new relative complexes of chargecompensated carborane anions [7,8-Me2-X-SMe2-nido-7,8C2B9H8]− (X = 9 and 10) with a common organometallic fragments and their thermo-induced isomerization reactions.

■

RESULTS AND DISCUSSION Previously we have shown that reaction of closo-type iridium(I) and rhodium(I) cyclooctadiene complexes 1,2-Me2-3,3-(cod)4-SMe2-3,1,2-closo-MC2B9H8 (M = Ir (1); M = Rh (3)) with hydrohalogens provides electron poor iridium(III) and rhodium(III) halides with pseudocloso-configuration 1,2-Me23,3-(X)2-4-SMe2-3,1,2-pseudocloso-MC2B9H8.14 The iridium(I) ethene derivative 1,2-Me2-3,3-(ethene)2-4-SMe2-3,1,2-closoMC2B9H8 isomerizes at RT within a few hours by a 1,2 → 1,7 carbon atoms isomerization scheme.16 Since cyclooctadiene complexes 1 and 3 could be isolated at RT, it was interesting to study their thermal isomerization reactions in controlled conditions. Iridacarborane 1 appears to be more stable at RT than its derivative with the ethene ligand. In the 11B{1H} NMR spectrum, a solution of complex 1 in CDCl3 exhibits signals of the only isomerization product, 2, after 8 days at RT (Scheme 1, isolated yields). The same reaction occurs in 1,2-dichloro-

Figure 1. Structure of complex 2. Ellipsoids are shown at the 30% probability level. Hydrogen atoms are not depicted for clarity. Selected bond lengths (Å): Ir2−C1 2.290(9), Ir2−B6 2.222(10), Ir2−B11 2.210(9), Ir2−B7 2.164(10), Ir2−B3 2.177(10), Ir2−C16 2.191(9), Ir2−C17 2.164(9), Ir2−C20 2.139(8), Ir2−C21 2.113(8), C1−C13 1.538(12), C8−C14 1.524(12), S1−B7 1.934(10), S1−C15A 1.781(9), S1−C15 1.811(9), C16−C17 1.393(13), C20−C21 1.412(12).

Scheme 1

IrC2B9H8. In the product of the cage rearrangement reaction, 2, the distance from the iridium atom to the pentagonal face defined by C(1), B(3), B(7), B(11), and B(6) atoms is less (1.600 Å) than that in parent complex 1 (1.647 Å), indicating stronger bonding of the iridium atom with carborane ligand in 2 compared with that in 1. The 11B{1H} NMR spectrum of 2 reveals nine resonances of approximately equal intensity between −3.9 and −20.6 ppm, with the one at −3.9 ppm remaining a singlet on retention of the proton coupling and thus being assigned to B7. The average 11 B chemical shift for 2, = −11.8 ppm ( = −10.5 ppm for 1), is indicative of a closo-MC2B9 metallacarborane.18 11B{1H}−11B{1H} COSY experiment data and resonances assignment for complex 2 (Figure 2) were in accord with the structure established by X-ray study. The 1H{11B} spectrum displays six resonances corresponding to the BH vertices with relative intensities 1:1:1:2:2:1 from high to low frequency. We were able to assign δ(1H) resonances for BH vertices by using a 1H−11B{1H} HETCOR NMR experiment (Figure S8). The most downfield resonance (δ = 4.18 ppm) among BH hydrogen atoms corresponds to the B(9)H hydrogen occupying the antipodal position to the iridium atom in icosahedral metallacarborane 2. The isomerization of rhodacarborane 1,2-Me2-3,3-(cod)-4SMe2-3,1,2-closo-RhC2B9H8 (3) requires significantly higher temperatures than those for iridium derivative 1. This fact is in accordance with the lower activation energy of metallacarborane isomerization for late transition metal complexes compared to that of their earlier period analogues. Stone et al. were the first to represent this trend for the relative molybda-

ethane solution at 60 °C, but it requires 3 h of heating on the thermostatic bath (Δt = ±0.5 °C) to be complete. The energy barrier of the isomerization of ethene complex 1,2-Me2-3,3(ethene)2-4-SMe2-3,1,2-closo-MC2B9H8, lower than of cyclooctadiene analog 1, could be associated with a higher conformational lability of ethene in comparison with that of 1,5-cyclooctadiene ligand which should decrease transition state energy in the case of the complex with ethene. Single-crystal X-ray diffraction study confirms 2,1,8-closoMC2B9H8 configuration of the metallacarborane cage in 2. Since compound 1 was actually a racemic mixture, complex 2 was isolated as a racemate. Interestingly, according to X-ray diffraction, racemate 2 crystallizes in centrosymmetric space group P21/c, and it contains both enantiomers in the unit cell. R-isomer of 2 is shown on Figure 1 (assigned as a clockwise numbering of the cage atoms when viewing from the side of the atom C1, cage atoms numbering priority was taken from the previous study).17 The S-isomer had similar structural properties, with the main difference in the olefinic bonds lengths in cyclooctadiene ligand. The average CC bond length was 1.403 Å for R-isomer, 1.440 Å for S-isomer, and 1.403 Å for ethene derivative 1,8-Me2-2,2-(ethene)2-7-SMe2-(R)-2,1,8-closoB


Article

Organometallics

conditions. Since we have shown that compound 4 does not convert to 5 on thermolysis, it is clear that 1,2 → 1,2 and 1,2 → 1,7 isomerizations are separate routs. Rhodacarborane 4 decomposes in a CH2Cl2 solution in air within a few hours, whereas its isomers 3 and 5 are stable under the same conditions. This fact reveals that the chemical behavior of isomeric metallacarboranes heavily depends on the position of cage carbon atoms. Structures of complexes 4 and 5 were determined according to their 11B{1H}−11B{1H} COSY NMR spectra (Figures S12 and S18). According to 1H−11B{1H} HETCOR and 1H with CW decoupling on 11B nuclei NMR experiments data for complex 4 (Figures S13 and S14) the most downfield signal (δ = 2.70 ppm) of BH hydrogen atoms corresponds to the B(9)H hydrogen antipodal to the rhodium atom. Compounds 4 and 5 reveal seven and nine resonances in 11B{1H} NMR spectra, respectively, with = −12.5 ppm for 4 and = −11.5 ppm for 5, indicative of closo-MC2B9 metallacarboranes. Since complexes 2 and 5 differ only in a metal atom of the metallacarborane cage, it is possible to estimate the impact of iridium and rhodium atoms on the chemical shifts δ(11B). 11 1 B{ H} NMR spectra and boron assignment for complexes 2 and 5 are represented on Figure 3. The most significant effect Figure 2. 11B{1H}−11B{1H} COSY NMR spectrum and resonances assignment for complex 2.

and tungstacarboranes19 and later Welch et al. for pallada- and platinacarboranes.13a Iron tricarbollide complex 1-Cp-1,2,3,4FeC3B8H11 requires heating to undergo polyhedral rearrangement, while its ruthenium analogue could not be isolated due to the fast isomerization at RT.20 Heating of complex 3 in o-xylene at 110 °C for 4 h resulted in a color change from yellow to dark-green. During the following workup, the green color of the solution disappeared indicating instability if the green byproduct. Nevertheless, two yellow complexes 1,2-Me2-4,4(cod)-8-SMe2-4,1,2-closo-RhC2B9H8 (4) and 1,8-Me2-2,2(cod)-7-SMe2-2,1,8-closo-RhC2B9H8 (5) were chromatographically isolated from reaction mixture with 42 and 11% yields, respectively (Scheme 2). Thus, the rearrangement reaction of 3

Figure 3. 11B{1H} NMR spectra and boron assignment for complexes 2 and 5.

appears in B9 resonances difference (Δδ = 3.3 ppm) antipodal to the metal atom and it is known in the literature as the antipodal effect (AE).23 The second significant effect apparent from Figure 3 is the resonances difference (Δδ = 2.3 ppm) between Me2S−B(7) boron atoms. The relativistic PBE/L2 calculations (including ZPE corrections) reveal that complexes 4 and 5 are more stable than the initial rhodacarborane, 3, by 6.7 and 10.3 kcal/mol, respectively. This result does not contradict a previous computational study of the relative thermodynamic stability of the isomeric cobaltacarboranes CpCoC2B9H11 that was shown to decrease in the 2,1,8-isomer > 4,1,2-isomer > 3,1,2isomer order.24 Thus, according to the computational data, isomerization of 3 should be attributed to the kinetically controlled reaction. Although 1,2 → 1,7 isomerization of metallacarboranes was shown most likely to proceed via the single triangle face rotation (TFR) mechanism,10b the mechanism of 1,2 → 1,2 rearrangements is still debatable. A 1,2 → 1,2 isomerization process of nikelacarboranes was rationalized by a single 120° rotation of the MB2 face.21e This approach could be applied for the explanation of rhodacarborane 3 isomerization to 4 but not for symmetrical iridacarborane 11 transformation to 13 (see below). We offer a mechanism of 3 to 4 rearrangement via the “boat” intermediate (Figure 4; animations for this transformation compiled from IRC procedures are available as Movies S1 and S2).

Scheme 2

proceeds via 1,2 → 1,2 and 1,2 → 1,7 schemes with a 1,2 → 1,2 scheme being the dominant route. The most examples of metallacarborane 1,2 → 1,2 isomerizations were presented for d10 metal complexes with electron-rich metal center.21 The only exception is cobaltocarborane 3-Cp-3,1,2-closo-CoC2B9H11 which 1,2 → 1,2 isomerization affords in low yields complex 4-Cp-4,1,2-closo-CoC2B9H11 via gas-phase thermolysis22 or oneelectron reduction followed by reflux in DME with subsequent aerobic oxidation.17 According to the 11B NMR spectrum, heating of complex 4 at 120 °C for 2 h in o-xylene does not lead to the formation of 5 or 3, indicating that 4 is not an intermediate in the isomerization of complex 3 to 5 and that isomerization of 3 to 4 is an irreversible process under these C


Article

Organometallics Scheme 4

Figure 4. Energy profile for the plausible mechanism of 3 to 4 isomerization. The values in parentheses correspond to relative ZPEcorrected energies in kcal/mol.

According to the calculated data, the rearrangement occurs via the intermediate (IM) and two transition states (TS1 and TS2). Interestingly, the first rate limiting step (TS1: ΔH⧧ = 29.2 kcal/mol) starts with a breaking of the C−C connectivity in metallacarborane cage in despite of the retained adjacency of Ccage atoms in product 4. The proposed mechanism of 3 → IM transformation can be described as a DSD rearrangement (Scheme 3) with a cleavage of two bonds (C2−C3 and B7− B8) and formation of two another (M−B7 and C3−B12). The intermediate formed (IM) has a boat conformation of the upper C2B4 belt and η6-coordination of the rhodium atom. A few examples of similar complexes with η6-coordination of a metal atom are known in the literature, moreover, they were shown to be intermediates in cage rearrangements of icosahedral molybdacarboranes.25 The second step of the reaction (IM → 4) has a significantly lower barrier (TS2: ΔH⧧ = 17.3 kcal/mol) and could be most easily rationalized by a single 90° rotation of the B7−C3 edge of the intermediate IM (Scheme 3). The first rate limiting step of 1,2 → 1,2 isomerization reaction of 3 has the activation energy barrier comparable with energy barriers (29.1−29.6 kcal/mol) calculated previously for the one step 1,2 → 1,7 rearrangements of the complexes 3,3,3-(CO)3-3,1,2-closo-MC2B9H11 (M = Re and Tc).10b Interaction of the thallium salt Tl[7,8-Me2-9-SMe2-7,8-nidoC2B9H8] with [Cp*RuCl]4 in THF furnishes new ruthenacarborane 1,2-Me2-3-(Cp*)-4-SMe2-3,1,2-closo-RuC2B9H8 (6) (Scheme 4). The 11B{1H} NMR spectrum of 6 displays seven resonances in the ratio 2:1:1:1:1:2:1 from high to low frequency and = −12.8 ppm, indicative of a closoMC2B9 metallacarborane. The heating of complex 6 at 80 °C for 2 h leads only to the partial decomposition of the initial

compound with no signs of isomerization products; heating in boiling o-xylene (146 °C) results in the complete decomposition of 6 within an hour. Previously, it was shown that the monophenyl substituted analogue of 6 ruthenacarborane 1-Ph3-(Cp*)-7-SMe2-3,1,2-closo-RuC2B9H9 isomerizes via 1,2 → 1,7 scheme even at RT giving 3-(Cp*)-4-SMe2-11-Ph-3,1,2-closoRuC2B9H9.26 This fact reveals the tendency of metal complexes with monophenyl-substituted carborane anion [7-Ph-9-SMe27,8-nido-C2B9H9]− to the easier isomerization in comparison to metal complexes with dimethyl-substituted carborane [7,8-Me29-SMe2-7,8-nido-C2B9H8]−. Moreover, the direction of metallacarboranes rearrangement reactions depends on the Ccage atom substituents: Complexes 1 and 3 isomerize with a migration of a Ccage atom close to the SMe2 moiety, whereas isomerization of 1-Ph-3-(Cp*)-7-SMe2-3,1,2-closo-RuC2B9H9 (with a Ph and SMe2 cage substituents separated by a {CH} unit) proceeds with a migration of the further Ccage bearing bulky Ph group. The structure of 6 was determined by a single-crystal X-ray diffraction study (Figure 5) which confirmed a closo-3,1,2RuC2B9H9 cage architecture with a C−C bond value being 1.674 Å. The distance from ruthenium atom to the mean plane defined by C(1), C(2), B(4), B(7), and B(8) atoms is 1.589 Å, comparable with the same distance in 3-(Cp*)-4-SMe2-3,1,2closo-RuC2B9H10 (1.608 Å).26 The plane defined by the metalbonded atoms of the Cp* ligand is not coplanar, and it is inclined by 7.4° to the metal-bonded C2B3 face due to the intramolecular crowding. It is well-known that the reduction of 1,2-closo-C2B10H12 results in C1−C2 bond breaking is fully consistent with the LUMO of o-carborane being antibonding between the Ccage

Scheme 3

D


Article

Organometallics

state on the ability of metallacarboranes to thermoinduced polyhedral isomerizations. A new 10-substituted charge-compensated carborane [7,8Me2-10-SMe2-7,8-nido-C2B9H9] (9) was synthesized by a known procedure30 comprising interaction of dicarbollide dianion [7,8-Me2-7,8-nido-C2B9H9]2− with dimethyl sulfide and acetaldehyde in the acidic media (Scheme 5). The 1H Scheme 5

Figure 5. Structure of complex 6. Ellipsoids are shown at the 30% probability level. Hydrogen atoms are not depicted for clarity. Selected bond lengths (Å): Ru3−C1 2.164(2), Ru3−C2 2.169(3), Ru3−B7 2.181(3), Ru3−B8 2.215(3), Ru3−B4 2.166(3), Ru3−C16 2.251(2), Ru3−C17 2.231(2), Ru3−C18 2.194(3), Ru3−C19 2.206(3), Ru3− C20 2.240(2), C1−C2 1.674(3), C1−C13 1.517(3), C2−C14 1.518(3), C16−C17 1.427(4), C17−C18 1.440(4), C18−C19 1.422(4), C19−C20 1.431(3), C20−C16 1.429(3), S1−B4 1.916(3), S1−C15 1.802(3), S1−C15A 1.810(3).

atoms.27 In contrast, reduction of metallacarboranes results in significant decrease of cage isomerization barrier.17,28 This result is expected if the first step in metallacarboranes rearrangements is a cage C−C bond cleavage which facilitates increasing of the electron density upon reduction. Following these reflections, it would be logical to suggest that metallacarboranes with the metal atom in the high oxidation state will have reduced ability to undergo the cage rearrangements due to acceptor properties of the metal atom. In order to verify this hypothesis, we have studied the thermal stability of the previously synthesized Ir(III) complex [1,2-Me2-3-(Cp)-4SMe2-3,1,2-closo-IrC2B9H8]PF6.29 This compound was recovered unchanged after its reflux in tetrachloroethane (146 °C) for 2 h. Its derivative with more electron-donating and sterically crowded pentamethylcyclopentadienyl ligand iridacarborane [1,2-Me2-3-(Cp*)-4-SMe2-3,1,2-closo-IrC2B9H8]NO3 (7NO3) was prepared by an interaction of the dimeric iridium chloride [Cp*IrCl2]2 with thallium salt Tl[7,8-Me2-9-SMe2-7,8-nidoC2B9H8] in the presence of TlNO3 (Scheme 4). Along with the cation complex 7NO3, a neutral iridacarborane 1,2-Me2-3(Cp*)-4-SMe-3,1,2-closo-IrC2B9H8 (8) was also isolated. Both compounds were studied crystallographically (Figures S41 and S42). Heating of 7NO3 under reflux in tetrachloroethane for 1 h affords neutral complex 8. Previously, we described the nucleophilic demethylation of SMe2 substituent in cationic metallacarboranes by halide anions.17 We assume that formation of complex 8 is a result of 7+ cation demethylation by a nitrate anion. Since salt 7NO3 decomposes fast upon heating, its analogue with nonnucleophilic anion 7PF6 was synthesized by a simple replacement of TlNO3 with TlPF6 (Scheme 4). Cationic complex 7PF6 and neutral derivative 8 were stable under reflux in the boiling tetrachloroethane for 2 h. Such a chemical behavior of 7PF6 is in contrast with that of complex 1 which isomerizes even at room temperature, displaying a significant influence of a metal center oxidation

NMR spectra of 9 shows two singlets assigned to the SMe2 and CcageMe groups, thus indicating a Cs molecular symmetry. The 11 1 B{ H} NMR spectra of 9 is in accordance with it exhibiting 1:2:2:2:1:1 pattern. Thallium salt 10 was prepared by reaction of 9 with a mixture of TlNO3 and KOH. If the diffusion of reagents is slow enough, then X-ray quality crystals of 10 could be obtained. The solid-state structure of 10 was established by a single-crystal X-ray diffraction study (Figure 6). Compound 10 has a distorted closo-3,1,2-TlC2B9 geometry. The thallium atom is located above the C2B3 pentagonal face with the Tl−B distance (avg 2.852 Å) being shorter than the Tl−Ccage (avg

Figure 6. Structure of complex 10. Ellipsoids are shown at the 30% probability level. Hydrogen atoms are not depicted for clarity. Selected bond lengths (Å): Tl3−B4 2.894(5), Tl3−B7 2.852(5), Tl3−B8 2.815(5), C1−C2 1.578(6), C1−B4 1.634(7), B4−B8 1.730(7), B7− B8 1.747(8), C2−B7 1.609(8), C1−C3 1.522(6), S1−B8 1.882(6), S1−C5 1.779(5). E


Article

Organometallics 3.043 Å). In contrast, sodium salt Na[9-SMe2-nido-7,8C2B9H11] crystallizes with the formation of centrosymmetric dimers linked by sodium cations with exonido Na···H−B coordination.31 Crystallographic data only for three thallium salts with dicarbollide anions are known to date: [Ph3PMe][3,1,2-TlC2B9H11],32 [PPN][3,1,2-TlC2B9H11],33 and Tl[1,2Me2-3,1,2-TlC2B9H11].34 In all the reported cases, thallium atom in closo-TlC2B9 cage has an exocloso type bonding Tl···H− B with other CarbTl molecule forming dimers ([PPN][3,1,2TlC2B9H11]) or polymers ([Ph3PMe][3,1,2-TlC2B9H11] and Tl[1,2-Me2-3,1,2-TlC2B9H11]). 10Tl packs in the solid state were found to form polymeric chains. Reaction of thallium salt 10 with [(cod)IrCl]2 in THF affords a new iridacarborane 1,2-Me2-3,3-(cod)-8-SMe2-3,1,2closo-IrC2B9H8 (11) with almost quantitative yield (Scheme 5). Complex 11 exhibits two singlets in 1H NMR spectrum corresponding to the SMe2 and CcageMe substituents and a 1:2:1:1:2:2 pattern in 11B{1H} NMR spectrum suggesting Cs molecular symmetry as in initial carborane 10. In comparison with its positional isomer 1, rearrangement in the metallacarborane cage for compound 11 proceeds at higher temperatures, and it furnishes two new complexes 1,8-Me22,2-(cod)-11-SMe2-2,1,8-closo-IrC2B9H8 (12) and 1,2-Me2-4,4(cod)-9-SMe2-4,1,2-closo-IrC2B9H8 (13) as a result of 1,2 → 1,7 and 1,2 → 1,2 isomerizations, respectively (Scheme 6). The

Figure 7. Structure of complex 12. Ellipsoids are shown at the 30% probability level. Hydrogen atoms are not depicted for clarity. Selected bond lengths (Å): Ir2−C1 2.283(3), Ir2−B3 2.175(3), Ir2−B7 2.197(3), Ir2−B11 2.192(3), Ir2−B6 2.180(3), Ir2−C16 2.149(3), Ir2−C17 2.144(3), Ir2−C20, 2.181(3), Ir2−C21 2.179(3), C1−C13 1.532(4), C8−C14 1.518(4), S1−B11 1.902(3), S1−C15 1.800(3), S1−C15A 1.794(3), C16−C17 1.432(4), C20−C21 1.421(4).

Scheme 6

integral intensities of olefinic (CH) protons in the 1H NMR spectrum (δ = 4.5−3.5 ppm) of the reaction mixture after heating of 11 in o-xylene at 110 °C reveal the reaction to be complete after 3 h with a formation of 12 and 13 in the molar ratio 7:1. The rate of the reaction was not affected significantly by the nature of a solvent. In our control experiment, complex 11 was heated in dichloroethane or acetonitrile at 80 °C. Conversion after 3 h was 61 and 68%, respectively (with almost the same distribution of isomers), revealing slightly higher reaction rate in the more polar acetonitrile. We were able to separate 12 and 13 by the chromatography on SiO2 in the eluent system ethyl acetate/petroleum ether (1:6; minor 13 was eluted first). The separation of 12 and 13 in the eluent system methylene chloride/petroleum ether (1:3) was complicated due to the opposite order of elution of 12 and 13 (13 was eluted second). X-ray diffraction study of 12 (Figure 7) and 13 (Figure 8) reveals 2,1,8-closo-MC2B9H8 configuration of the metallacarborane cage for 12 and 4,1,2-closo-MC2B9H8 configuration for 13. Distances from the iridium atom to the pentagonal face of the carborane ligand for 12 (1.598 Å) and 13 (1.597 Å) are comparable with that for complex 2 (1.600 Å). The cage C−C bond in 13 where iridium atom bounds to the CB4 pentagonal face (1.674 Å) is shorter than that in complex 1 having Ir−C2B3 bonding (1.716 Å).14 Isomers 12 and 13 were characterized by a combination of 1 H and 11B NMR spectroscopies. The 11B{1H} NMR spectrum

Figure 8. Structure of complex 13. Ellipsoids are shown at the 30% probability level. Hydrogen atoms are not depicted for clarity. Selected bond lengths (Å): Ir4−C1 2.252(6), Ir4−B3 2.198(6), Ir4−B5 2.170(7), Ir4−B8 2.215(7), Ir4−B9 2.188(7), Ir4−C16 2.144(6), Ir4−C17 2.129(6), Ir4−C20 2.168(6), Ir4−C21 2.158(6), C1−C2 1.674(9), C1−C13 1.512(8), C16−C17 1.432(9), C20−C21 1.413(9), S1−B9 1.907(7), S1− C15A 1.791(8).

of 12 consists of five resonances between −4.2 and −21.7 ppm and = −10.6 ppm with integrals in the ratio 1:4:1:2:1 from high to low frequency, while 11B NMR spectrum of 13 reveals nine resonances of the approximately equal intensity between 1.6 and −22.6 ppm and = −11.9 ppm. 11 1 B{ H}−11B{1H} COSY experiment data and resonances assignment for complex 13 (Figure S40) were in accordance with X-ray diffraction study. F


Article

Organometallics

a Bruker Avance-400 spectrometer operating at 400.13 and 128.38 MHz, respectively. The purity of compounds was confirmed by the combination of elemental analysis and NMR spectra. 1,8-Me2-2,2-(cod)-7-SMe2-2,1,8-closo-IrC2B9H8 (2). A solution of 1,2-Me2-3,3-(cod)-4-SMe2-3,1,2-IrC2B9H8 (50 mg) in 3 mL of 1,2dichloroethane was heated at 60 °C for 3 h. The solvent was removed in vacuo, and the residue was chromatographed on SiO2 with the mixture CH2Cl2−petroleum ether (1:2) as eluent. After removal of the solvent in vacuo the residue was crystallized from diethyl ether− petroleum ether. Yield of the product as colorless crystals was 46 mg (92%). 1H{11B} (acetone-d6, δ) 4.20 (br t, 2H, CH−cod, 3JHH = 8 Hz), 4.18 (s, 1H, B(9)H), 3.73 (td, 2H, CH−cod, 3JHH = 8 Hz, 3JHH = 4 Hz), 2.95 (s, 3H, SMe), 2.71 (s, 3H, SMe), 2.58 (s, 1H, B(6)H), 2.58−2.48 (m, 1H, CH2−cod), 2.52 (s, 1H, B(4)H), 2.48−2.29 (m, 5H, CH2−cod), 2.23−2.13 (m, 2H, CH2−cod), 2.12 (s, 2H, B(3,12)H), 1.86 (s, 3H, Me−carb), 1.83 (s, 2H, B(5,10)H), 1.72 (s, 3H, Me−carb), 1.48 (s, 1H, B(11)H). 11B{1H} NMR (acetone-d6, δ) −3.9 (s, 1B, B(7)), −5.3 (d, 1B, B(6)), −7.7 (d, 1B, B(9)), −8.6 (d, 1B, B(3)), −10.6 (d, 1B, B(11)), −14.0 (d, 1B, B(12)), −17.4 (d, 1B, B(5)), −18.2 (d, 1B, B(4)), −20.6 (d, 1B, B(10)). Anal. Calcd for C14H32B9IrS: C, 32.21; H, 6.18; B, 18.64%. Found: C, 32.14; H, 6.19; B, 18.68%. 1,2-Me2-4,4-(cod)-8-SMe2-4,1,2-closo-RhC2B9H8 (4) and 1,8Me2-2,2-(cod)-7-SMe2-2,1,8-closo-RhC2B9H8 (5). A solution of 1,2Me2-3,3-(cod)-4-SMe2-3,1,2-RhC2B9H8 (171 mg) in o-xylene (10 mL) was heated at 110 °C for 4 h. After that time, the color of the solution was changed from yellow to dark green. The solvent was removed in vacuo, and the residue was chromatographed on SiO2 with a mixture ethyl acetate−petroleum ether (1:3) as eluent. Two mobile yellow bands were subsequently collected as solids after removal of the solvent in vacuo and crystallization from diethyl ether−petroleum ether. Compound 4. Yield 72 mg (42%). Rf = 0.27. The sample of crystalline 4 decomposed within a few month upon storage on air. 1 H{11B} (acetone-d6, δ) 4.30−4.24 (m, 2H, CH−cod), 4.15−4.09 (m, 2H, CH−cod), 2.70 (s, 1H, B(11)H), 2.54−2.30 (m, 8H, CH2−cod), 2.52 (s, 3H, SMe), 2.46 (s, 3H, SMe), 2.02 (s, 1H, B(10)H), 1.87 (s, 3H, Me−carb), 1.85 (s, 1H, B(3 or 9)H), 1.77 (s, 1H, B(5)H), 1.69 (s, 1H, B(3 or 9)H), 1.50 (s, 1H, B(6 or 7)H), 1.49 (s, 3H, Me−carb), 1.30 (s, 1H, B(12)H). 11B{1H} NMR (acetone-d6, δ) −3.2 (1B, B(5)), −5.2 (1B, B(8)SMe2), −8.7 (2B, B(3,9)), −11.7 (1B, B(7)), −12.3 (1B, B(11)), −19.5 (2B, B(10,6)), −23.3 (1B, B(12)). Anal. Calcd for C14H32B9RhS: C, 38.86; H, 7.45; B, 22.49%. Found: C, 38.75; H, 7.47; B, 22.37%. Compound 5. Yield 19 mg (11%). Rf = 0.10. 1H (acetone-d6, δ) 4.62−4.50 (m, 2H, CH−cod), 4.34−4.25 (m, 2H, CH−cod), 3.08 (s, 3H, SMe), 2.76 (s, 3H, SMe), 2.55−2.37 (m, 6H, CH2−cod), 2.30− 2.20 (m, 2H, CH2−cod), 1.87 (s, 3H, Me−carb), 1.65 (s, 3H, Me− carb). 11B{1H} NMR (acetone-d6, δ) −1.6 (1B, B(7)SMe2), −4.7 (1B, B(6)), −9.3 (1B, B(11)), −9.8 (1B, B(3)), −11.0 (1B, B(9)), −13.1 (1B, B(12)), −16.1 (1B, B(5)), −17.5 (1B, B(4)), −20.8 (1B, B(10)). Anal. Calcd for C14H32B9RhS: C, 38.86; H, 7.45; B, 22.49%. Found: C, 38.78; H, 7.49; B, 22.41%. 1,2-Me2-3-(Cp*)-4-SMe2-3,1,2-closo-RuC2B9H8 (6). A suspension of [Cp*RuCl]4 (35 mg, 32 μmol) and Tl[9-SMe2-7,8-Me2-7,8C2B9H8] (58 mg, 135 μmol) was stirred in THF (3 mL) for 3 h at RT. The solution was filtered through a thin layer of Al2O3 and washed with CH2Cl2. The solvent was reduced in vacuo to the volume ∼0.3 mL, and crystallization of product was initiated by addition of methanol. The beige crystalline powder was separated from the mother liquor, and washed with cold methanol and dried; yield was 40 mg (68%). 1H (CDCl3, δ) 2.58 (s, 3H, SMe), 2.40 (s, 3H, SMe), 1.99 (s, 3H, Me−carb), 1.87 (s, 3H, Me−carb), 1.84 (s, 15H, Cp*). 11 1 B{ H} NMR (CDCl3, δ) −2.9 (2B, BSMe2), −4.9 (1B), −8.6 (1B), −15.1 (1B), −19.5 (1B), −20.0 (2B), −21.7 (1B). Anal. Calcd for C16H35B9RuS: C, 41.97; H, 7.70; B, 21.25%. Found: C, 42.87; H, 7.73; B, 20.68%. [1,2-Me2-3-(Cp*)-4-SMe2-3,1,2-closo-IrC2B9H8]NO3 (7NO3), 7PF6, and 1,2-Me2-3-(Cp*)-4-SMe-3,1,2-closo-IrC2B9H8 (8). A mixture of [Cp*IrCl2]2 (35 mg, 44 μmol), Tl[9-SMe2-7,8-Me2-7,8-

Since complexes 1 and 11 differ only in a position of SMe2 substituent, it is obvious that differences in the chemical behavior of these complexes are determined by the electronic effect of the SMe2 moiety. The crystallographic data for relative complexes 3,3-(cod)-X-SMe2-3,1,2-RhC2B9H10 (X = 4 and 8) clearly exhibit the influence of SMe2 group on the structural parameters. The cage C−C bond in 3,3-(cod)-4-SMe2-3,1,2RhC2B9H10 (1.628(4) Å, analog of 1)35 is significantly longer than that in complex 3,3-(cod)-8-SMe2 -3,1,2-RhC 2B9H10 (1.559(7) Å, analog of 11)36 with symmetrical emplacement of SMe2 substituent revealing stronger bonding of Ccage atoms in the latter complex. We assume the same trend in the case of iridium complexes 1 and 11. The weaker cage C−C bonding in 1 if compared to 11 should facilitate lengthening of the C1···C2 distance on the first step of isomerization reaction and makes the rearrangement possible at lower temperatures. Stone et al. have suggested that the dissociation of cyclooctadiene ligand from 3-cod-3,1,2-PdC2B9H11 may facilitate an 1,2 → 1,2 isomerization.21g The isomerization of 11 occurs at a higher temperature when compared with that of complex 1, and the same process with decomplexation might have sense in case of 11. Dissociation of the cod ligand from 11 leads to the species with electron-deficient configuration of the metal atom that could be stabilized by the cage C−C bond lengthening giving iridacarborane with pseudocloso configuration of the cage similar to that of known halide complexes 1,2Me2-3,3-(X)2-4-SMe2-3,1,2-pseudocloso-MC2B9H8 (M = Rh and Ir; X = Cl, Br, and I).14 Subsequent attack of free cod on iridium atom resumes the rearrangement process providing more thermodynamically stable isomer 13 with closoarchitecture.

■

CONCLUSIONS Polyhedral rearrangement of iridacarborane 1 proceeds at RT and affords a product of 1,2 → 1,7 isomerization, 2. The simple modification of compound 1 by a replacement of iridium to rhodium atom or displacement of SMe2 substituent in initial complex 1 results in the significant change of the chemical behavior of new compounds. It is expressed in elevated isomerization temperatures. Furthermore, rhodacarborane 3 and iridacarborane 11 isomerize by both 1,2 → 1,7 and 1,2 → 1,2 schemes, with 1,2 → 1,2 being the major route for 3 and the minor for 11. The iridium(III) analogues of complex 1 are stable upon heating to 146 °C, revealing a significant role of a metal center oxidation state in the ability of metallacarboranes to thermoinduced polyhedral isomerization. Ruthenium derivative 6 with dimethyl substituted carborane ligand [7,8-Me29-SMe2-7,8-nido-C2B9H8]− does not undergo cage isomerization, while its analogue with monophenyl substituted ligand [7-Ph-9-SMe2-7,8-nido-C2B9H8]− isomerizes even at RT, indicating that metallacarboranes based on [7-Ph-9-SMe2-7,8nido-C2B9H8]− tend to the easier isomerization.

■

EXPERIMENTAL SECTION

General Considerations. All reactions were carried out under argon atmosphere using standard Schlenk techniques with subsequent workup in air. All solvents were purified and degassed by standard procedures. Starting materials [Cp*RuCl]4,37 [Cp*IrCl2]2,38 [(cod)IrCl]2,39 1,2-Me2-3,3-(cod)-4-SMe2-3,1,2-closo-RhC2B9H8,14 1,2-Me23,3-(cod)-4-SMe2-3,1,2-closo-IrC2B9H8,14,15 Tl[9-SMe2-7,8-Me2-7,8nido-C2B9H8],14 [1,2-Me2-3-(Cp)-4-SMe2-3,1,2-closo-IrC2B9H8]PF6,29 and 1,2-Me2-1,2-closo-C2B10H1040 were prepared as described in the literature. 1H and 11B{1H} NMR spectra (δ in ppm) were recorded on G


Article

Organometallics

was heated at 110 °C for 3 h. The solvent was removed in vacuo, and the residue was chromatographed on SiO2 with a mixture ethyl acetate−petroleum ether (1:6) as eluent. Two mobile colorless bands were subsequently collected as solids after removal of the solvent in vacuo and crystallization from diethyl ether−petroleum ether. Compound 12. Yield 103 mg (82%). Rf = 0.27. 1H (acetone-d6, δ) 4.21 (br t, 2H, CH−cod, 3JHH = 8 Hz), 3.61 (td, 2H, CH−cod, 3JHH = 8 Hz, 3JHH = 4 Hz), 2.81−2.73 (m, 2H, CH2−cod), 2.78 (s, 3H, SMe), 2.55 (s, 3H, SMe), 2.51−2.41 (m, 2H, CH2−cod), 2.32−2.23 (m, 2H, CH2−cod), 2.02−1.93 (m, 2H, CH2−cod), 1.90 (s, 3H, Me−carb), 1.55 (s, 3H, Me−carb). 11B{1H} NMR (acetone-d6, δ) −4.2 (1B, BSMe2), −8.5 (4B), −16.3 (1B), −19.1 (2B), −21.7 (1B). Anal. Calcd for C14H32B9IrS: C, 32.21; H, 6.18; B, 18.64%. Found: C, 32.09; H, 6.24; B, 18.63%. Compound 13. Yield 7 mg (6%). Rf = 0.34. 1H (acetone-d6, δ) 3.99 (br t, 2H, CH−cod, 3JHH = 8 Hz), 3.69 (td, 2H, CH−cod, 3JHH = 8 Hz, 3 JHH = 4 Hz), 2.68−2.60 (m, 2H, CH2−cod), 2.61 (s, 3H, SMe), 2.46−2.25 (m, 4H, CH2−cod), 2.38 (s, 3H, SMe), 2.19 (s, 3H, Me− carb), 2.02 (s, 3H, Me−carb), 2.10−1.97 (m, 2H, CH2−cod). 11B{1H} NMR (acetone-d6, δ) 1.6 (1B, B(9)SMe2), −6.2 (1B, B(3)), −8.3 (1B, B(11)), −9.8 (1B, B(5)), −11.2 (1B, B(8)), −15.1 (1B, B(12)), −16.5 (1B, B(6)), −18.9 (1B, B(7)), −22.6 (1B, B(10)). Anal. Calcd for C14H32B9IrS: C, 32.21; H, 6.18%. Found: C, 32.14; H, 6.21%. X-ray Crystallography. Crystals of the complexes were grown by a slow diffusion in a two-layer system: CH2Cl2−petroleum ether (for 2, 6, 8, and 12) or CH2Cl2−diethyl ether (for 7). Crystals of thallium salt 10 were grown by a method described above in the synthetic part. Compound 13 was crystallized by a gas-phase diffusion of the petroleum ether in a benzene solution of 13. Main crystallographic data and details of structure refinement are listed in Tables S1−S3. Single-crystal X-ray diffraction experiments were carried out with a APEX2 2DUO diffractometer, using graphite monochromated Mo Kα radiation (λ = 0.71073 Å). The structures were solved by the direct method and refined by the full-matrix least-squares against F2 in the anisotropic approximation (for non-hydrogen atoms). Positions of hydrogen atoms in the carborane fragment were found from difference Fourier maps; the positions of others were calculated. All hydrogen atoms were refined in the isotropic approximation in the riding model. All calculations were performed using the SHELXTL software.41 Computational Details. Geometry optimizations were performed without constraints using PBE exchange-correlation functional,42 the scalar-relativistic Hamiltonian,43 atomic basis sets of generally contracted Gaussian functions,44 and a density-fitting technique45 as implemented in Priroda 6 code.46 The all-electron triple-ζ basis set L2 augmented by two polarization functions was used.47 Frequency calculations were performed to confirm the nature of the stationary points to yield one imaginary frequency for the transition states and none for the minima. The nature of all transition states was investigated by the analysis of vectors associated with the imaginary frequency and by the calculations of the Intrinsic Reaction Coordinate (IRC).48 The ChemCraft program49 was used for molecular modeling and visualization.

C2B9H8] (40 mg, 93 μmol), and TlNO3 (33 mg, 124 μmol) was stirred in 1,2-dichloroethane (2 mL) for 3 h at RT. The solution was decantated from TlCl precipitate, the solvent was reduced in vacuo to a volume of ∼1.5, and 10 mL of diethyl ether was added. Beige crystals of 7NO3 were separated from the mother liquor, and the product was recrystallized from acetone−diethyl ether, yield was 24 mg (45%). 1H (CDCl3, δ) 2.73 (s, 6H, SMe2), 2.37 (s, 3H, Me−carb), 2.19 (s, 3H, Me−carb), 2.11 (s, 15H, Cp*). 11B{1H} NMR (CDCl3, δ) 0.1 (1B), −2.0 (1B), −4.6 (2B, BSMe2), −10.8 (1B), −15.1 (2B), −16.8 (2B). Anal. Calcd for C16H35B9IrNO3S: C, 31.45; H, 5.77; B, 15.92%. Found: C, 30.95; H, 5.37; B, 15.51%. A solvent from the mother liquor was removed in vacuo, and the residue was chromatographed on SiO2 with the mixture CH2Cl2− petroleum ether (1:2) as eluent. After removal of the solvent in vacuo, the residue was crystallized from methanol; yield of 8 was 19 mg (40%). 1H (CDCl3, δ) 2.21 (s, 3H, Me−carb), 2.18 (s, 3H, Me−carb), 2.01 (s, 15H, Cp*), 1.63 (s, 3H, SMe). 11B{1H} NMR (CDCl3, δ) 3.0 (1B, BSMe), −0.8 (1B), −1.4 (1B), −6.2 (1B), −12.1 (1B), −13.4 (1B), −16.4 (2B), −19.0 (1B). Anal. Calcd for C15H32B9IrS: C, 33.74; H, 6.04; B, 18.22%. Found: C, 33.44; H, 6.14; B, 18.50%. 7PF6 was prepared analogously to 7NO3 using TlPF6 instead of TlNO3. Yield was 41%. Anal. Calcd for C16H35B9IrPF6S: C, 27.69; H, 5.08; B, 14.02%. Found: C, 26.96; H, 4.91; B, 13.63%. 10-SMe2-7,8-Me2-7,8-nido-C2B9H9 (9). A mixture of 1,2-Me2-1,2C2B10H10 (650 mg, 3.77 mmol) and KOH (650 mg, 11.6 mmol) was refluxed in ethanol (10 mL) for 7 h. Ethanol was removed in vacuo, and white crystalline material was dissolved in water (10 mL). Then, toluene (10 mL) containing Me2S (1.1 mL, 0.92 g, 14.9 mmol) and concentrated HCl (5 mL) were added successively to the water solution. After the addition of CH3C(O)H (0.8 mL, 0.63 g, 14.4 mmol), the reaction mixture was shaken for 1 min in the closed flask, and it was left to stir for 4 h at RT. Organic layer was separated, washed with water, and dried with Na2SO4. The solvent was removed in vacuo, and the residue was crystallized from methanol at −6 °C. The crystalline product was filtered off, washed with cold methanol, and dried; yield was 350 mg. The mother liquor was evaporated, and the residue was chromatographed on SiO2 with a mixture CH2Cl2− petroleum ether (1:1) as eluent (Rf = 0.48). The solvent was removed in vacuo and the product crystallized from Et2O−petroleum ether; yield was 90 mg. Overall yield was 440 mg (52%). 1H (CDCl3, δ) 2.55 (s, 6H, SMe2), 1.49 (s, 6H, Me−carb), −0.50/−1.35 (m, 1H). 11 1 B{ H} NMR (CDCl3, δ) −9.4 (1B), −10.3 (2B), −16.7 (2B), −17.7 (2B), −27.0 (1B, BSMe2), −36.3 (1B). Anal. Calcd for C6H21B9S: C, 32.37; H, 9.51; B, 43.71%. Found: C, 31.41; H, 9.18; B, 43.94%. Tl[10-SMe2-7,8-Me2-7,8-nido-C2B9H8] (10). A solution of 10SMe2-7,8-Me2-7,8-C2B9H9 (264 mg, 1.19 mmol) in DMSO (6.5 mL) was added to a solution of KOH (400 mg, 7.14 mmol) in water (6.5 mL), and the mixture was stirred for 0.5 h (solution A). Then, a solution (solution B) of TlNO3 (350 mg, 1.32 mmol) in water (6.5 mL) was added to solution A dropwise. After stirring for 0.5 h, a yellow solid was filtered off, washed with water, EtOH, and CH2Cl2, and dried in vacuo. Yield was 478 mg (95%). Crystals of 10 suitable for X-ray diffraction study were grown by a slow diffusion of solution A (0.5 mL) and solution B (0.25 mL diluted up to 2 mL with water) in the NMR tube. Anal. Calcd for C6H20B9STl: C, 16.92; H, 4.73; B, 22.84%. Found: C, 16.89; H, 4.79; B, 22.87%. 1,2-Me2-3,3-(cod)-8-SMe2-3,1,2-closo-IrC2B9H8 (11). A mixture of [(cod)IrCl]2 (70 mg, 0.104 mmol) and Tl[10-SMe2-7,8-Me2-7,8C2B9H8] (93 mg, 0.218 mmol) was stirred in THF (5 mL) for 3 h. The precipitate of TlCl was filtered off, and the filtrate was evaporated in vacuo. The yellow residue was reprecipitated by methanol from THF. Yield was 102 mg (94%). 1 H (CDCl3, δ) 3.86−3.79 (m, 4H, CH−cod), 2.47 (s, 6H, SMe2), 2.29 (s, 6H, Me−carb), 2.28−2.10 (m, 8H, CH2−cod). 11B{1H} NMR (CDCl3, δ) −0.3 (1B, BSMe2), −10.6 (2B), −11.8 (1B), −14.1 (1B), −14.8 (2B), −18.0 (2B). Anal. Calcd for C14H32B9IrS: C, 32.21; H, 6.18; B, 18.64%. Found: C, 31.84; H, 6.19; B, 18.63%. 1,8-Me2-2,2-(cod)-11-SMe2-2,1,8-closo-IrC2B9H8 (12) and 1,2Me2-4,4-(cod)-9-SMe2-4,1,2-closo-IrC2B9H8 (13). A solution of 1,2Me2-3,3-(cod)-4-SMe2-3,1,2-IrC2B9H8 (126 mg) in o-xylene (5 mL)

■

ASSOCIATED CONTENT

S Supporting Information *

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.organomet.6b00858. NMR spectra, XRD data, and computational chemistry data (PDF) Movie S1: DSD process transforming 3 to IM (AVI) Movie S2: Edge rotation transforming IM to 4 (AVI) Crystallographic information file for compound 2 (CIF) Crystallographic information file for compound 6 (CIF) Crystallographic information file for compound 7NO3 (CIF) Crystallographic information file for compound 8 (CIF) Crystallographic information file for compound 10 (CIF) H


Article

Organometallics

■

Crystallographic information file for compound 12 (CIF) Crystallographic information file for compound 13 (CIF) checkCIF/PLATON report for compound 10 (PDF) checkCIF/PLATON report for compound 12 (PDF)

(10) (a) Johnson, B. F. G. J. Chem. Soc., Chem. Commun. 1986, 27− 30. (b) Sugden, I. J.; Plant, D. F.; Bell, R. G. Chem. Commun. 2013, 49, 975−977. (11) (a) Kaesz, H. D.; Bau, R.; Beall, H. A.; Lipscomb, W. N. J. Am. Chem. Soc. 1967, 89, 4218−4220. (b) Wu, S.-h.; Jones, M. J. Am. Chem. Soc. 1989, 111, 5373−5384. (c) Gimarc, B. M.; Warren, D. S.; Ott, J. J.; Brown, C. Inorg. Chem. 1991, 30, 1598−1605. (12) Edvenson, G. M.; Gaines, D. F. Inorg. Chem. 1990, 29, 1210− 1216. (13) (a) Kyd, G. O.; Yellowlees, L. J.; Welch, A. J. J. Chem. Soc., Dalton Trans. 1994, 3129−3134. (b) Tutusaus, O.; Viñas, C.; Kivekäs, R.; Sillanpäa,̈ R.; Teixidor, F. Chem. Commun. 2003, 2458−2459. (c) Vinogradov, M. M.; Zakharova, M. V.; Timofeev, S. V.; Loginov, D. A.; Sivaev, I. B.; Nelyubina, Y. V.; Starikova, Z. A.; Bregadze, V. I.; Kudinov, A. R. Inorg. Chem. Commun. 2015, 51, 80−82. (d) Safronov, A. V.; Dolgushin, F. M.; Petrovskii, P. V.; Chizhevsky, I. T. Organometallics 2005, 24, 2964−2970. (14) Vinogradov, M. M.; Starikova, Z. A.; Loginov, D. A.; Kudinov, A. R. J. Organomet. Chem. 2013, 738, 59−65. (15) 1H (acetone-d6, δ) 3.98−3.92 (m, 2H, CH−cod), 3.75−3.70 (m, 2H, CH−cod), 2.91 (s, 3H, SMe), 2.58 (s, 3H, SMe), 2.53−2.35 (m, 6H, CH2−cod), 2.31 (s, 3H, Me−carb), 2.17−2.11 (m, 2H, CH2− cod), 1.62 (s, 3H, Me−carb). 11B{1H} NMR (acetone-d6, δ) −1.9 (1B), −6.1 (1B, BSMe2), −7.1 (1B), −7.9 (1B), −12.3 (1B), −13.8 (2B), −15.2 (1B), −16.0 (1B). (16) Vinogradov, M. M.; Nelyubina, Y. V.; Ikonnikov, N. S.; Strelkova, T. V.; Kudinov, A. R. J. Organomet. Chem. 2016, 805, 54− 58. (17) Man, W. Y.; Rosair, G. M.; Welch, A. J. Dalton Trans. 2015, 44, 15417−15419. (18) Thomas, R. Ll.; Welch, A. J. J. Chem. Soc., Dalton Trans. 1997, 631−636. (19) Li, S.; Stone, F. G. A. Polyhedron 1993, 12, 1689−1696. (20) Perekalin, D. S.; Trifonova, E. A.; Glukhov, I. V.; Holub, J.; Kudinov, A. R. Collect. Czech. Chem. Commun. 2010, 75, 1139−1148. (21) (a) Churchill, M. R.; Gold, K. J. Am. Chem. Soc. 1970, 92, 1180− 1187. (b) Paxson, T. E.; Kaloustian, M. K.; Tom, G. M.; Wiersema, R. J.; Hawthorne, M. F. J. Am. Chem. Soc. 1972, 94, 4882−4888. (c) Carr, N.; Mullica, D. F.; Sappenfield, E. L.; Stone, F. G. A. Inorg. Chem. 1994, 33, 1666−1673. (d) Garrioch, R. M.; Kuballa, P.; Low, K. S.; Rosair, G. M.; Welch, A. J. J. Organomet. Chem. 1999, 575, 57−62. (e) Robertson, S.; Ellis, D.; Rosair, G. M.; Welch, A. J. Appl. Organomet. Chem. 2003, 17, 518−524. (f) Robertson, S.; Garrioch, R. M.; Ellis, D.; McGrath, T. D.; Hodson, B. E.; Rosair, G. M.; Welch, A. J. Inorg. Chim. Acta 2005, 358, 1485−1493. (g) Fallis, K.; Mullica, D. F.; Sappenfield, E. L.; Stone, F. G. A. Inorg. Chem. 1994, 33, 4927− 4933. (h) Mandal, D.; Man, W. Y.; Rosair, G. M.; Welch, A. J. Dalton Trans. 2016, 45, 15013−15025. (22) Kaloustian, M. K.; Wiersema, R. J.; Hawthorne, M. F. J. Am. Chem. Soc. 1972, 94, 6679−6686. (23) (a) Siedle, A. R.; Bodner, G. M.; Garber, A. R.; Beer, D. C.; Todd, L. J. Inorg. Chem. 1974, 13, 2321−2324. (b) Planas, J. G.; Viñas, C.; Teixidor, F.; Light, M. E.; Hursthouse, M. B.; Ogilvie, H. R. Eur. J. Inorg. Chem. 2005, 2005, 4193−4205. (24) Perekalin, D. S.; Kudinov, A. R. Russ. Chem. Bull. 2005, 54, 1603. (25) (a) Dunn, S.; Weller, A. S. Chem. Commun. 1998, 1065−1067. (b) McIntosh, R. D.; Ellis, D.; Giles, B. T.; Macgregor, S. A.; Rosair, G. M.; Welch, A. J. Inorg. Chim. Acta 2006, 359, 3745−3753. (26) Rosair, G. M.; Welch, A. J.; Weller, A. S. Organometallics 1998, 17, 3227−3235. (27) McKay, D.; Macgregor, S. A.; Welch, A. J. Chem. Sci. 2015, 6, 3117−3128. (28) Hanusa, T. P.; Todd, L. J. Polyhedron 1985, 4, 2063−2066. (29) Vinogradov, M. M.; Nelyubina, Y. V.; Loginov, D. A.; Kudinov, A. R. J. Organomet. Chem. 2015, 798, 257−262. (30) (a) Plesek, J.; Jelínek, T.; Mares, F.; Hermánek, S. Collect. Czech. Chem. Commun. 1993, 58, 1534−1547. (b) Tutusaus, O.; Teixidor, F.; Núñez, R.; Viñas, C.; Sillanpäa,̈ R.; Kivekäs, R. J. Organomet. Chem. 2002, 657, 247−255.

AUTHOR INFORMATION

Corresponding Author

*E-mail: [email protected]. Fax: +7 499 135 5085. ORCID

Mikhail M. Vinogradov: 0000-0001-6159-6977 Notes

The authors declare no competing financial interest. † A.R.K.: Deceased October 22, 2016.

■

ACKNOWLEDGMENTS This work was supported by the Russian Foundation for Basic Research (grant # 16-33-00166). Yu.V.N. gratefully acknowledges financial support from the Foundation of the President of the Russian Federation (MK-6224.2016.3). NMR measurements were supported by the grant of the President of Russian Federation (projects MK-2179.2017.3 and MK-6320.2016.3).

■

REFERENCES

(1) (a) Grimes, R. N. Carboranes, 2nd ed.; Academic: London, 2011. (b) Poater, J.; Solà, M.; Viñas, C.; Teixidor, F. Angew. Chem., Int. Ed. 2014, 53, 12191−12195. (2) (a) Hawthorne, M. F. Comments Inorg. Chem. 2010, 31, 153−163. (b) Leśnikowski, Z. J. J. Med. Chem. 2016, 59, 7738−7758. (3) (a) Henderson, L. J.; Keller, T. M. Macromolecules 1994, 27, 1660−1661. (b) Brown, D. A.; Colquhoun, H. M.; Daniels, A. J.; MacBride, J. A. H.; Stephenson, I. R.; Wade, K. J. Mater. Chem. 1992, 2, 793−804. (4) Dash, B. P.; Satapathy, R.; Gaillard, E. R.; Maguire, J. A.; Hosmane, N. S. J. Am. Chem. Soc. 2010, 132, 6578−6587. (5) Spokoyny, A. M.; Li, T. C.; Farha, O. K.; Machan, C. W.; She, C.; Stern, C. L.; Marks, T. J.; Hupp, J. T.; Mirkin, C. A. Angew. Chem., Int. Ed. 2010, 49, 5339−5343. (6) (a) El-Zaria, M. E.; Arii, H.; Nakamura, H. Inorg. Chem. 2011, 50, 4149−4161. (b) Lavallo, V.; Wright, J. H.; Tham, F. S.; Quinlivan, S. Angew. Chem., Int. Ed. 2013, 52, 3172−3176. (c) Tsang, M. Y.; Viñas, C.; Teixidor, F.; Planas, J. G.; Conde, N.; SanMartin, R.; Herrero, M. T.; Domínguez, E.; Lledós, A.; Vidossich, P.; Choquesillo-Lazarte, D. Inorg. Chem. 2014, 53, 9284−9295. (d) Yinghuai, Z.; Hosmane, N. S. J. Organomet. Chem. 2013, 747, 25−29. (e) Tutusaus, O.; Viñas, C.; Núñez, R.; Teixidor, F.; Demonceau, A.; Delfosse, S.; Noels, A. F.; Mata, I.; Molins, E. J. Am. Chem. Soc. 2003, 125, 11830−11831. (7) (a) Popescu, A. R.; Teixidor, F.; Viñas, C. Coord. Chem. Rev. 2014, 269, 54−84. (b) Yao, Z.-J.; Jin, G.-X. Coord. Chem. Rev. 2013, 257, 2522−2535. (c) Gleeson, B.; Carroll, P. J.; Sneddon, L. G. J. Am. Chem. Soc. 2013, 135, 12407−12413. (d) El-Hellani, A.; Kefalidis, C. E.; Tham, F. S.; Maron, L.; Lavallo, V. Organometallics 2013, 32, 6887−6890. (e) Spokoyny, A. M.; Reuter, M. G.; Stern, C. L.; Ratner, M. A.; Seideman, T.; Mirkin, C. A. J. Am. Chem. Soc. 2009, 131, 9482− 9483. (f) Himmelspach, A.; Finze, M.; Raub, S. Angew. Chem., Int. Ed. 2011, 50, 2628−2631. (g) Eleazer, B. J.; Smith, M. D.; Popov, A. A.; Peryshkov, D. V. J. Am. Chem. Soc. 2016, 138, 10531−10538. (h) Eleazer, B. J.; Smith, M. D.; Peryshkov, D. V. Organometallics 2016, 35, 106−112. (i) Kudinov, A. R.; Perekalin, D. S.; Rynin, S. S.; Lyssenko, K. A.; Grintselev-Knyazev, G. V.; Petrovskii, P. V. Angew. Chem., Int. Ed. 2002, 41, 4112−4114. (j) Robertson, A. P. M.; Beattie, N. A.; Scott, G.; Man, W. Y.; Jones, J. J.; Macgregor, S. A.; Rosair, G. M.; Welch, A. J. Angew. Chem., Int. Ed. 2016, 55, 8706−8710. (8) Grafstein, D.; Dvorak, J. Inorg. Chem. 1963, 2, 1128−1133. (9) (a) Lipscomb, W. N. Science 1966, 153, 373−378. (b) Johnson, B. F. G.; Roberts, Y. V.; Parisini, E. Inorg. Chim. Acta 1993, 211, 17− 21. (c) Gimarc, B. M.; Zhao, M. Inorg. Chem. 1996, 35, 825−834. I


Article

Organometallics (31) Lyssenko, K. A.; Golovanov, D. G.; Meshcheryakov, V. I.; Kudinov, A. R.; Antipin, M. Yu. Russ. Chem. Bull. 2005, 54, 933−941. (32) Colquhoun, H. M.; Greenhough, T. J.; Wallbridge, M. G. H. Acta Crystallogr., Sect. B: Struct. Crystallogr. Cryst. Chem. 1978, 34, 2373−2376. (33) Manning, M. J.; Knobler, C. B.; Hawthorne, M. F.; Do, Y. Inorg. Chem. 1991, 30, 3589−3591. (34) Jutzi, P.; Wegener, D.; Hursthouse, M. B. Chem. Ber. 1991, 124, 295−299. (35) Kyd, G. O.; Yellowlees, L. J.; Welch, A. J. J. Chem. Soc., Dalton Trans. 1994, 3129−3134. (36) Núñez, R.; Tutusaus, O.; Teixidor, F.; Viñas, C.; Sillanpäa,̈ R.; Kivekäs, R. Organometallics 2004, 23, 2273−2280. (37) Fagan, P. J.; Ward, M. D.; Calabrese, J. C. J. Am. Chem. Soc. 1989, 111, 1698−1719. (38) White, C.; Yates, A.; Maitlis, P. M.; Heinekey, D. M. Inorg. Synth. 1992, 29, 228−234. (39) Crabtree, R. H.; Quirk, J. M.; Felkin, H.; Fillebeen-Khan, T. Synth. React. Inorg. Met.-Org. Chem. 1982, 12, 407−413. (40) Long, J. A.; Marder, T. B.; Behnken, P. E.; Hawthorne, M. F. J. Am. Chem. Soc. 1984, 106, 2979−2989. (41) Sheldrick, G. M. Acta Crystallogr., Sect. A: Found. Crystallogr. 2008, 64, 112−122. (42) Perdew, J. P.; Burke, K.; Ernzerhof, M. Phys. Rev. Lett. 1996, 77, 3865−3868. (43) Dyall, K. G. J. Chem. Phys. 1994, 100, 2118−2127. (44) Laikov, D. N. Chem. Phys. Lett. 2005, 416, 116−120. (45) Laikov, D. N. Chem. Phys. Lett. 1997, 281, 151−156. (46) Laikov, D. N.; Ustynyuk, Yu. A. Russ. Chem. Bull. 2005, 54, 820−826. (47) Misochko, E. Ya.; Akimov, A. V.; Belov, V. A.; Tyurin, D. A.; Laikov, D. N. J. Chem. Phys. 2007, 127, 084301. (48) Gonzalez, C.; Schlegel, H. B. J. Chem. Phys. 1991, 95, 5853− 5860. (49) Zhurko, G. A. ChemCraft 1.6, 2008. http://www.chemcraftprog. com.

J


Polyhedral Rearrangements in the Complexes of Rhodium and Iridium

Recommend Documents