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Photolysis of THF solutions of 10-vertex [N(PPh3)2][6,6,6-(CO)3-closo-6,1-FeCB8H9] (1) in the presence of PEt3 results in [N(PPh3)2][6-CO-6,6-(PEt3)2-closo-6,1-FeCB8H9] (2), which readily oxidizes in air to form the neutral and paramagnetic, 17-electron Fe(III) species [6-CO-6,6-(PEt3)2-closo-6,1-FeCB8H9] (3). Substitution of one PEt3 ligand by cyanide occurs on addition of [NBun4][CN] and Me3NO to 3 in CH2Cl2, giving [NBun4][6-CO-6-CN-6-PEt3-closo-6,1-FeCB8H9] (4). When [IrCl(CO)(PPh3)2] and Tl[PF6] (1:1) are added to CH2Cl2 solutions of 4, the neutral, paramagnetic complex [6-{(μ-CN)Ir(CO)(PPh3)2}-6-CO-6-PEt3-closo-6,1-FeCB8H9] (5) is obtained. Results of X-ray diffraction studies carried out on 3 and 5 are presented herein.

Addition of Me3NO to CH2Cl2 solutions of [1-OH-2,2,2-(CO)3-closo-2,1,10-FeC2B7H8] (1a) affords [2,2-(CO)2-1,2-μ-{OCH2NMe2}-closo-2,1,10-FeC2B7H8] (2), which contains a five-membered FeNCOC unit. The same reaction in MeCN as solvent gives [2,2-(CO)2-1,2-μ-{OC(R)NH}-closo-2,1,10-FeC2B7H8] (3a, R = Me). Analogous derivatives [R = CH═C(H)Me (3c), p-C6H4NO2 (3d), p-C6H4Br (3f), p-C6H4C(H)O (3g), p-C6H4C≡CH (3h), p-C5H4N (3i), or NH2 (3j)] are obtained from treatment of CH2Cl2 solutions of 1a with other cyano-containing substrates and Me3NO. The μ-imidate species 3 undergo a variety of subsequent reactions. Thus, oxidative coupling of compound 3h in CH2Cl2, in the presence of CuCl−TMEDA (TMEDA = Me2NCH2CH2NMe2), affords dimeric [2,2-(CO)2-closo-2,1,10-FeC2B7H8-1,2-μ-{OC(NFeH)-p-C6H4-C≡C}]2 (4), which reacts with [Co2(CO)8] in CH2Cl2 to give the tetracluster species [2,2-(CO)2-closo-2,1,10-FeC2B7H8-1,2-μ-{OC(NFeH)-p-C6H4-{(μ-η2:η2-C≡C)Co2(CO)6}}]2 (5). Conversely, 3f forms a bis(cluster) species, [2,2′-dppb-{2-C...

Reaction between [NBun4][closo-1-CB7H8] and [Mn2(CO)10] in THF (THF = tetrahydrofuran) at reflux temperatures, or at room temperature with ultraviolet irradiation, followed by addition of [N(PPh3)2]Cl, affords the manganese−dicarbollide salt [N(PPh3)2][1-OH-2,2,2-(CO)3-closo-2,1,10-MnC2B7H8] (1). Addition of NOBF4 to 1 gives the neutral species [1-OH-2,2-(CO)2-2-NO-closo-2,1,10-MnC2B7H8] (2), which readily undergoes CO substitution with PEt3 in the presence of Me3NO to yield [1-OH-2-CO-2-NO-2-PEt3-closo-2,1,10-MnC2B7H8] (3). Protonation of 1 in the presence of dialkyl sulfides SR2 affords the neutral complexes [1-SR2-2,2,2-(CO)3-closo-2,1,10-MnC2B7H8] [R = Me (4); SR2 = S(CH2)4 (5); R = {CH2CH═CH2} (6)]; the synthesis of 5 is accompanied by formation of a boron-substituted relative, [1-OH-6-{S(CH2)4}-2,2,2-(CO)3-closo-2,1,10-MnC2B7H7] (7). Addition of Me3NO to 6 in CH2Cl2 produces the anions [1-(SCH2CH═CH2)-2,2,2-(CO)3-closo-2,1,10-MnC2B7H8]− and [1,2-σ:η2-(SCH2CH═CH2)-2,2-(CO)2-closo-2,1,10-MnC2B7H8]−, i...

Reaction of [Pt3(CNR)6] with arachno-4-R′-4-CB8H13 in THF (tetrahydrofuran) gives the platinamonocarborane species [9,9-(CNR)2-6-R′-arachno-9,6-PtCB8H11] (R = But, R′ = H (1); R = Xyl (C6H3Me2-2,6), R′ = H (2); R = But, R′ = Ph (3)). The related compound [9,9-(PMe2Ph)2-arachno-9,6-PtCB8H12] (5) can be synthesized by treating arachno-4-CB8H14 with [PtMe2(PMe2Ph)2] in CH2Cl2. Compounds 1–3 and 5 are all formed in high yields (>80%), enabling reactivity studies to be carried out. A single isocyanide ligand in 1 can be easily exchanged for a phosphine, as is the case with [9-CNBut-9-PPh3-arachno-9,6-PtCB8H12] (6), or, by using bidentate dppe (Ph2PCH2CH2PPh2), both isocyanide groups are replaced, giving [9,9-dppe-arachno-9,6-PtCB8H12] (7). Treatment with [NEt4][CN] allows the isocyanides in 1 to be replaced by cyanide ligands, giving the dianionic complex [NEt4]2[9,9-(CN)2-arachno-9,6-PtCB8H12] (8) or the monoanionic species [NEt4][9-CNBut-9-CN-arachno-9,6-PtCB8H12] (9) depending on the stoichiometry of the re...

Reaction of [NBun4][closo-1-CB7H8] with [Fe2(CO)9] in refluxing THF (tetrahydrofuran) gives the neutral ferradicarborane [2,2,2-(CO)3-1-OH-closo-2,1,10-FeC2B7H8] (3), which, upon treatment with PEt...

The cyano-iridium-diiron complex [N(PPh3)2][8,10-{Ir(μ-PPh2)(CN)(Ph)(PPh3)}-8-(μ-H)-6,6,6,10,10-(CO)5-closo-6,10,1-Fe2CB7H7] (3) has been synthesized by reaction of a THF solution of [8,10-{Ir(μ-PPh2)(Ph)(CO)(PPh3)}-8-(μ-H)-6,6,6,10,10-(CO)5-closo-6,10,1-Fe2CB7H7] (2) with [NEt4]CN in the presence of Me3NO, followed by metathesis with [N(PPh3)2]Cl. Compound 3 in CH2Cl2 with [CuCl(PPh3)]4 or [AuCl(PPh3)], in the presence of TlPF6, yields [8,10-{Ir(μ-PPh2)(Ph){(CN)M(PPh3)n}(PPh3)}-8-(μ-H)-6,6,6,10,10-(CO)5-closo-6,10,1-Fe2CB7H7] (M = Cu, n = 2 (4) or M = Au, n = 1 (5), respectively). The structures of 4 and 5 have been established by X-ray diffraction experiments.

Reaction between [PPh4][closo-4-CB 8 H 9 ] and [Ru 3 (CO) 12 ] in refluxing toluene affords the unprecedented hexaruthenium metallacarborane salt [PPh4][2,3,7-{Ru(CO) 3 }-2,6,11-{Ru(CO)3}-7,11,12-{Ru(CO)3}-3,6,12-(μ-H)3-2,2,7,7,11,11-(CO) 6 -closo-2,7,11,1-Ru 3 CB 8 H 6 ] (1a), which contains a planar Ru 6 'raft' supported by a {CB 8 } monocarborane cluster. Addition of [CuCl(PPh 3 )] 4 and TI[PF 6 ] to a CH 2 Cl 2 solution of 1a results in simple cation replacement, forming the analogous [Cu(PPh 3 ) 3 ] + salt (1b). The phenyl-substituted monocarborane [NEt4][6-Ph-nido-6-CB 9 H 11 ] reacts with [Ru 3 (CO) 12 ] in refluxing 1,2-dimethoxyethane to afford the pentaruthenium cluster species [N(PPh 3 ) 2 ]-[2,3,7-{Ru(CO)3}-3,4,8-{Ru(CO)3}-7,8-(μ-H)2-1-Ph-2,2,3,3,4,4-(CO)6-hypercloso-2,3,4,1-Ru 3 CB 8 H 6 ] (2), after addition of [N(PPh 3 )2]Cl. Treatment of 2 with [CuCl(PPh 3 )] 4 and TI[PF 6 ] in CH 2 Cl 2 forms the zwitterionic complex [10,12-{exo-Cu(PPh3)2}-2,3,7-{Ru(CO)3}-3,4,8-{Ru(CO)3}-7,8,10,12-(μ-H)4-1-Ph-2,2,3,3,4,4-(CO)6-hyperctoso-2,3,4,1-Ru 3 -CB 8 H 4 ] (3). Substitution of CO by PPh 3 with concomitant cation replacement occurs on introduction of [Aucl(PPh 3 )], Tl[PF 6 ], and PPh 3 to a CH 2 Cl 2 solution of 2, forming [Au(PPh3)2][2,3,7-{Ru(CO)2PPh3}-3,4,8-{Ru(CO)2PPh3}-7,8-(μ-H)2-1-Ph-2,2,3,3,4,4-(CO)6-hyperc/oso-2,3,4,1-Ru 3 CB 8 H 6 ] (4). Crystallographic studies confirmed the cluster architectures in 1b, 2, and 3.

Reaction of [Co(CO) 3 (NO)] with [2-NMe 3 - closo -2-CB 10 H 10 ] in refluxing CH 2 Cl 2 affords the mono- and di-cobalt complexes [1-NMe 3 -2-CO-2-NO- closo -2,1-CoCB 10 H 10 ] ( 3 ) and [2,7-{Co(CO)(NO)}-7-(μ-H)-1-NMe 3 -2-CO-2-NO- closo -2,1-CoCB 10 H 9 ] ( 4 ), respectively, of which 4 contains formally both Co(I) and Co(–I) centers. Compound 4 reacts with CO to give 3 , or with donor ligands L in the presence of Me 3 NO to afford simple substituted species, [1-NMe 3 -2-L-2-NO- closo -2,1-CoCB 10 H 10 ] (compounds 5 ; L = PEt 3 , PPh 3 , CNBu t ).

The docosahedral metallacarboranes 4,4-(PMe(2)Ph)2-4,1,6-closo-PtC(2)B(10)H(12), 4,4-(PMe(2)Ph)2-4,1,10-closo-PtC(2)B(10)H(12), and [N(PPh(3))2][4,4-cod-4,1,10-closo-RhC(2)B(10)H(12)] were prepared by reduction/metalation of either 1,2-closo-C(2)B(10)H(12) or 1,12-closo-C(2)B(10)H(12). All three species were fully characterized, with a particular point of interest of the latter being the conformation of the {ML2} fragment relative to the carborane ligand face. Comparison with conformations previously established for six other ML(2)C(2)B(10) species of varying heteroatom patterns (4,1,2-MC(2)B(10), 4,1,6-MC(2)B(10), 4,1,10-MC(2)B(10), and 4,1,12-MC(2)B(10)) reveals clear preferences. In all cases a qualitative understanding of these was afforded by simple MO arguments applied to the model heteroarene complexes [(PH3)2PtC(2)B(4)H(6)]2- and [(PH3)2PtCB(5)H(6)]3-. Moreover, DFT calculations on [(PH3)2PtC(2)B(4)H(6)]2- in its various isomeric forms approximately reproduced the observed conformations in the 4,1,2-, 4,1,6-, and 4,1,10-MC(2)B(10) species, although analogous calculations on [(PH3)2PtCB(5)H(6)]3- did not reproduce the conformation observed in the 4,1,12-MC(2)B(10) metallacarborane. DFT calculations on (PH3)2PtC(2)B(10)H(12) yielded good agreement with experimental conformations in all four isomeric cases. Apparent discrepancies between observed and computed Pt-C distances were probed by further refinement of the 4,1,2- model to 1,2-(CH2)3-4,4-(PMe3)2-4,1,2-closo-PtC(2)B(10)H(10). This still has a more distorted structure than measured experimentally for 1,2-(CH2)3-4,4-(PMe(2)Ph)2-4,1,2-closo-PtC(2)B(10)H(10), but the structural differences lie on a very shallow potential energy surface. For the model compound a henicosahedral transition state was located 8.3 kcal mol(-1) above the ground-state structure, consistent with the fluxionality of 1,2-(CH2)3-4,4-(PMe(2)Ph)2-4,1,2-closo-PtC(2)B(10)H(10) in solution.

Treatment of [N(PPh 3 ) 2 ][NEt 4 ][1,1,1-(CO) 3 -2-Ph-closo-1,2-MCB 9 H 9 ] (M = Mn (la), Re (1b)) with sources of the cations {M'(CO) 2 } + (M' = Ir, Rh) affords the bimetallic species [N(PPh 3 ) 2 ][1,3,6-(M-(CO)3}-3,6-(μ-H)2-1,1-(CO)2-2-Ph-closo-1,2-M'CB 9 H 7 ] (M = Re, M' = Ir (2a), Rh (2b); M = Mn, M' = Ir (2c), Rh (2d)). In these, the {M(CO) 3 } fragment, formerly a cluster vertex, has assumed an exopolyhedral role, while the {M'(CO) 2 } units now occupy a site within the cluster. Compounds 2 convert to [N(PPh3)2][l,3-{M(CO)4}-3-(μ-H)-l,l-(CO)2-2-Ph-closo-1,2-M'CB 9 H 8 ] (M = Re, M' = Ir (3a), Rh (3b); M = Mn, M' = Ir (3c), Rh (3d)) by deliberate CO addition or by CO scavenging. Reaction of 2b with PEt 3 gives [N(PPh 3 ) 2 ][1,3-{Re(CO)3(PEt3)}-3-(μ-H)-1,1-(CO)2-2-Ph-closo-1,2-RhCB 9 H 8 ] (4), which has a mirror-symmetric structure, whereas 2a with NH 2 C 6 H 4 Me-1,4 affords [N(PPh3)2][l,3-{Re(CO)3-(NH2C6H4Me-1,4)}-3-(μ-H)-1,1-(CO)2-2-Ph-closo-1,2-IrCB 9 H 8 ] (5), which is asymmetric. The structures of 2b, 3b, and 5 have been confirmed by X-ray diffraction studies.

Treatment of [N(PPh3)2][1,3,6-{Re(CO)3}-3,6-(μ-H)2-1,1-(CO)2-2-Ph-closo-1,2-IrCB9H7] (2a) with {Cu(PPh3)}+ gives two types of polymetallic species: [1,4,7-{Cu(PPh3)}-1,5,6-{Re(CO)3}-4,5,6,7-(μ-H)4-1,1-(CO)2-2-Ph-closo-1,2-IrCB9H5] (4a), containing a V-shaped Re−Ir−Cu trimetallic unit, and [1,3,6-{Cu2(PPh3)2}-3,6-(μ-H)2-1,1-(CO)2-2-Ph-closo-1,2-IrCB9H7] (5a), containing an IrCu2 triangle. In contrast, [N(PPh3)2][1,3,6-{Re(CO)3}-3,6-(μ-H)2-1,1-(CO)2-2-Ph-closo-1,2-RhCB9H7] (2b) with the same copper cation essentially affords only the corresponding RhCu2 species 5b. Reaction of 2a with {Au(PPh3)}+ yields up to three types of polymetallic species, namely, [1,6-{Au2(PPh3)2}-6-(μ-H)-1,1-(CO)2-2-Ph-closo-1,2-IrCB9H8] (7a), which contains an IrAu2 triangle and is thus related to compounds 5, [1,3,6-{Au2(PPh3)2Re(CO)3}-6-(μ-H)-1,1-(CO)2-2-Ph-closo-1,2-IrCB9H7] (8a), in which there is an {Au2IrRe} “butterfly” arrangement of metal atoms that is supported by the carborane, and the tetrametallic [1,3-{Au3(PPh3)3}-1,1...

Reaction of [Mn(NCMe)3(CO)3][PF6] with Li3[7-NHBut-nido-7-CB10H10] in THF (THF = tetrahydrofuran) affords the twelve-vertex manganacarborane dianion [1-NHBut-2,2,2-(CO)3-closo-2,1-MnCB10H10]2−, isolated as the bis-[N(PPh3)2]+ salt (5a). This species reacts with {Pt(dppe)}2+ (dppe = Ph2PCH2CH2PPh2) to afford the bimetallic complex [1-NH2But-2,3-{Pt(dppe)}-2,2,2-(CO)3-closo-2,1-MnCB10H9] (7) which has an Mn–Pt bond. In contrast, with {Cu(PPh3)}+ the anion of 5a yields a CuMnCu trimetallic compound [1-{NH(But)Cu(PPh3)}-2,3,7-{Cu(PPh3)}-3,7-(μ-H)2-2,2,2-(CO)3-closo-2,1-MnCB10H8] (8) in which one of the Cu centers is bonded to Mn, whilst the other is attached to the pendant NHBut group. Upon treatment with Ag+, compound 5a is oxidized giving the very unusual Mn(III)-carbonyl complex [1,2-μ-NHBut-2,2,2-(CO)3-closo-2,1-MnCB10H10] (9a) in which the carborane ligand formally acts as an eight-electron donor to manganese. The novel structural features of compounds 7, 8, and 9a have been confirmed by X-ray diffraction studies.

Treatment of [closo-1-CB7H8]- with [Co2(CO)8] in THF at room temperature affords the 10-vertex dicobalt−monocarbollide anion [6,10-(μ-CO)-6,6,10,10-(CO)4-closo-6,10,1-Co2CB7H8]-, isolated as the [N(PPh3)2]+ salt (6). The analogous 12-vertex species [N(PPh3)2][2,3-(μ-CO)-2,2,3,3-(CO)4-closo-2,3,1-Co2CB9H10] (7) is obtained similarly from [arachno-6-CB9H14]- and [Co2(CO)8] heated to 50 °C. Both 6 and 7 contain a cobalt−cobalt bond that is bridged by one CO ligand. In contrast, the same cobalt reagent with [closo-4-CB8H9]- at room temperature gives the tricobalt species [6,7,10-{Co2(μ-CO)(CO)5}-7-(μ-H)-6,6-(CO)2-closo-6,1-CoCB8H7]-, similarly isolated as its [N(PPh3)2]+ salt (8a). The latter contains a V-shaped tricobalt unit, part of a {Co3B} butterfly that is edge-fused to a {CoCB8} cluster. Compounds 6 and 7 with CF3SO3Me in CH2Cl2−THF (1:1) give the zwitterionic, B-substituted complexes [6,10-(μ-CO)-6,6,10,10-(CO)4-8-{O(CH2)4}-closo-6,10,1-Co2CB7H7] (9) and [2,3-(μ-CO)-2,2,3,3-(CO)4-12-{O(CH2)4}-closo-2,...

Protonation of the 11-vertex bis-molybdenum−monocarbollide salt [NEt4]3[1,3,6-{Mo(CO)3}-3,6-(μ-H)2-1,1,1-(CO)3-2-Ph-closo-1,2-MoCB9H7] (1) with H[BF4]·OEt2 in the presence of CO and [NEt4]I results...

Treatment of the 11-vertex carborane anion [closo-2-CB(10)H(11)](-) with Ni(0) reagents in tetrahydrofuran (THF) affords-via oxidative insertion reactions-12-vertex Ni(II) complexes, isolated as the salts [N(PPh(3))(2)][2,2-L(2)-closo-2,1-NiCB(10)H(11)] (L = CO (1a), CNBu(t) (1b), and CNXyl (1c; Xyl = C(6)H(3)Me(2)-2,6); L(2) = cod (1d; cod = 1,2:5,6-eta-cyclo-octa-1,5-diene)). One CO ligand in 1a is readily replaced by donors L' in the presence of Me(3)NO to give the species [N(PPh(3))(2)][2-CO-2-L'-closo-2,1-NiCB(10)H(11)] (L' = PEt(3) (1e), PPh(3) (1f), CNBu(t) (1g), and CNXyl (1h)). The anionic complexes themselves readily react with hydride abstracting reagents in the presence of donor ligands to yield zwitterionic complexes in which boron vertexes bear substituents that are bound through C, N, or O atoms. Thus, for example, 1c with H(+) and CNXyl gives [2,2,7-(CNXyl)(3)-closo-2,1-NiCB(10)H(10)] (2b), while 1f with Me(+) in the presence of OEt(2) affords [2-CO-2,11-{mu-PPh(2)(C(6)H(4)-o)}-7-OEt(2)-closo-2,1-NiCB(10)H(9)] (4), in which an additional cycloboronation of one phosphine phenyl ring has occurred. In contrast, 1f with Me(+) in the presence of NCMe gives a mixture of the isomers [2-CO-2-PPh(3)-7-{(X)-N(Me)=C(H)Me}-closo-2,1-NiCB(10)H(10)] (X identical with E (5c) and Z (5d)). X-ray diffraction analyses of compounds 1a, 2b, 4, and 5c confirmed their important structural features.

The reagent [NBun4][closo-1-CB7H8] reacts with [Fe3(CO)12] in THF at reflux temperatures to give the anion [7,7,7-(CO)3-closo-7,1-FeCB7H8]-, isolated as the [N(PPh3)2]+ salt (1a). Further heating with excess [Fe3(CO)12] inserts a second {Fe(CO)3} fragment to yield [6,6,6, 10,10,10-(CO)6-closo-6,10,1-Fe2CB7H8]-, also isolated as its [N(PPh3)2]+ salt (2). Compounds 1a and 2 react with [CuCl(PPh3)]4 and Tl[PF6] to yield the bi- and trimetallic complexes [6,7,9-{Cu(PPh3)}-6,9-(μ-H)2-7,7,7-(CO)3-closo-7,1-FeCB7H6] (4) and [7,10-{Cu(PPh3)}-7-(μ-H)-6,6,6,10,10,10-(CO)6-closo-6,10,1-Fe2CB7H7] (5), respectively. Compound 2 with Ag[PF6] and PPh3 fails to give the analogous Ag−Fe2CB7 species, but instead under oxidative conditions one {Fe(CO)3} moiety is removed from the anion of 2 and the anion of 1a is isolated as the [Ag(PPh3)3]+ salt (1b). The bimetallic species [6,7,9-{Ag(PPh3)}-6,9-(μ-H)2-7,7,7-(CO)3-closo-7,1-FeCB7H6] (6) is also obtained. Treatment of 2 with CF3SO3H in donor solvents L yields the zwitterioni...

In toluene at reflux temperatures [Ru3(CO)12] and 7-SMe2-nido-7-CB10H12 give the charge-compensated cluster complex [1-SMe2-2,2-(CO)2-7,11-(μ-H)2-2,7,11-Ru2(CO)6-closo-2,1-RuCB10H8] (1) . Treatment of 1 with dppm in THF affords [1-SMe2-2,2-(CO)2-7,11-(μ-H)2-2,7,11-Ru2(μ -dppm)(CO)4-closo-2,1-RuCB10H8] (2) [dppm = bis(diphenylphosphino)methane; THF = tetrahydrofuran]. The latter complex on heating in THF with [ $${\hbox{NBu}^{n}}_{4}$$ ]F yields the salt [ $${\hbox{NBu}^{n}}_{4}$$ ][1-SMe-2,2-(CO)2-7,11-(μ-H)2-2,7,11-Ru2(μ -dppm)(CO)4-closo-2,1-RuCB10H8] (3). Reaction of 3 with [AuCl(PPh3)] and Tl[PF6] gives the neutral zwitterionic complex [1-S(Me)Au (PPh3)-2,2-(CO)2-7,11-(μ-H)2-2,7,11-Ru2(μ-dppm)(CO)4-closo-2,1-RuCB10H8] (4). The structures of 1, 3 and 4 were determined by single-crystal X-ray diffraction studies.

Reaction of Na2[nido-7,9-C2B10H12] with either [ReBr(CO)3(THF)2] or [Mn(NCMe)3(CO)3][PF6] in THF (THF = tetrahydrofuran), followed by introduction of [N(PPh3)2]Cl, affords the 13-vertex monoanionic...

Reduction of closo-1,2-C2B10H12, with sodium naphthalide in THF (THF = tetrahydrofuran), followed by addition of [Rh2(μ-Cl)2(cod)2] (cod = 1,2:5,6-η-cyclooctadiene) and [N(PPh3)2]Cl, affords the mo...

Treatment of Na2[7,8-R2-nido-7,8-C2B9H9] (R = H, Me) with the reagent [Mn(NCMe)3(CO)3][PF6] affords the anions [3,3,3-(CO)3-1,2-R2-closo-3,1,2-MnC2B9H9]-, typically isolated as Cs+ or [N(PPh3)2]+ s...

Treatment of [NEt4][6-Ph-nido-6-CB9H11] in tetrahydrofuran (THF) with BunLi (2 equiv) followed by [ReBr(THF)2(CO)3] gives the title rhenacarborane dianion isolated, by addition of [N(PPh3)2]Cl, as a mixed salt [N(PPh3)2][NEt4][1,1,1-(CO)3-2-Ph-closo-1,2-ReCB9H9], whose structure was confirmed by X-ray diffraction. The closo 11-vertex dianion reacts readily with several cationic transition metal−ligand fragments, affording products with novel structures in which the electrophilic metal groups are attached exo-polyhedrally to the {closo-1,2-ReCB9} cage system by rhenium−metal bonds supported by three-center two-electron B−H⇀M linkages. Species prepared include [1,3-{M(dppe)}-3-μ-H-1,1,1-(CO)3-2-Ph-closo-1,2-ReCB9H8] (M = Ni, Pd, or Pt; dppe = Ph2PCH2CH2PPh2), [N(PPh3)2][1,3,6-{M(CO)3}-3,6-(μ-H)2-1,1,1-(CO)3-2-Ph-closo-1,2-ReCB9H7] (M = Mn or Re), and [1,6-{M(PPh3)}-1,7-{M(PPh3)}-6,7-(μ-H)2-1,1,1-(CO)3-2-Ph-closo-1,2-ReCB9H7] (M = Cu or Au). Of these, the structures of the platinum−rhenium and dicopper−rheni...

The carborane anion [closo-2-CB10H11]− undergoes a polyhedral expansion reaction with [Co(CO)3(NO)] in tetrahydrofuran (THF) to afford [2-CO-2-NO-closo-2,1-CoCB10H11]−, isolated as the [N(PPh3)2]+ salt 1a. An X-ray diffraction study confirmed that the NO group is linearly bonded to cobalt. The CO ligand in 1a is readily replaced by PPh3 in the presence of Me3NO, or by PEt3 or CNBut directly, to give the species [N(PPh3)2][2-L-2-NO-closo-2,1-CoCB10H11] [L=PPh3 (1b), PEt3 (1c), CNBut (1d)]. Reactions of these anionic complexes with electrophilic reagents are exemplified by treatment of 1c with CF3SO3Me in CH2Cl2–THF to give the neutral, zwitterionic B-THF species [2-NO-2-PEt3-7-O(CH2)4-closo-2,1-CoCB10H10] (3a), and by the reaction of 1b with [CuCl(PPh3)]4 and Tl[PF6] in THF to give bimetallic [2,7,11-{Cu(PPh3)}-7,11-(μ-H)2-2-NO-2-PPh3-closo-2,1-CoCB10H9] (4b). X-ray diffraction analysis of crystals of 4b confirmed the presence of a CoCu bond.

The room-temperature reaction of Li2[7-NMe3-nido-7-CB10H10] with [Mo(CO)4{NH(CH2)5}2] in THF (THF = tetrahydrofuran), followed by oxidation with CF3SO3Me or CH2CHCH2Br, gives the anion [2,3-µ-{N(CH2)5}-2,2,2-(CO)3-closo-2,1-MoCB10H10]−, isolated as the [N(PPh3)2]+ salt 3a. This salt may similarly be isolated following the direct reaction of 7-NMe3-nido-7-CB10H12 with [Mo(CO)4{NH(CH2)5}2] in refluxing THF. An X-ray diffraction study confirmed the absence of the C–NMe3 group in the anion and formation of an intramolecular piperidinyl bridge between molybdenum and boron. The related compound [N(PPh3)2][1-NH2-2,3-µ-{N(CH2)5}-2,2,2-(CO)3-closo-2,1-MoCB10H9] 4 is obtained from Li[7-NH2-nido-7-CB10H12] with [Mo(CO)4{NH(CH2)5}2] in refluxing THF. Treatment of 3a or 4 with {M(PPh3)}+ (M = Cu, Ag) yields heterobimetallic complexes containing direct Mo–M bonds, of which [2,7,11-{Cu(PPh3)}-7,11-(µ-H)2-2,3-µ-{N(CH2)5}-2,2,2-(CO)3-closo-2,1-MoCB10H8] has been studied by X-ray diffraction analysis. In THF solution, 4 is oxidized by iodine or N-chlorosuccinimide affording the MoIV species [1,2-µ-NH2-2,3-µ-{N(CH2)5}-2,2-(CO)2-2-X-closo-2,1-MoCB10H9] (X = I, Cl, respectively). An X-ray diffraction study of the iodo derivative showed that it contained two intramolecular amino bridges between cage vertices and molybdenum. Treatment of these species with PEt3 in refluxing THF leads to displacement of a carbonyl ligand rather than an amino bridge.

The complex [N(PPh3)2][1,2-μ-{NHC(Me)O}-2,2,2-(CO)3-closo-2,1-MoCB10H10] (1) is obtained by deprotonating 7-NH2C(O)Me-nido-7-CB10H12 with NaH in THF, adding NCMe and [Mo(CO)6], and refluxing the mixture, with a final addition of [N(PPh3)2]Cl. Compound 1 undergoes cage-substitution reactions with O(CH2)4 or Me2S in the presence of CF3SO3Me and H2SO4, respectively, to yield charge-compensated complexes [1,2-μ-{NHC(Me)O}-2,2,2-(CO)3-7-L-closo-2,1-MoCB10H9] (L = O(CH2)4 (2), SMe2 (3)), and with [Me2NCH2]Cl and TlPF6 to afford [1,2-μ-{NHC(Me)O}-2,2,2-(CO)3-7-NMe3-closo-2,1-MoCB10H9] (4).

The carborane 7-NHCMe2-nido-7-CB10H12 reacts with [RhCl(PPh3)3] in toluene at reflux temperatures to give the charge-compensated 16-electron Rh(III) complex [1-NHCMe2-2-Cl-2-PPh3-closo-2,1-RhCB10H10] (1) in good yield. The structure of this product was established by X-ray diffraction (XRD). Upon methanolysis 1 affords [1-NH3-2-Cl-2-PPh3-closo-2,1-RhCB10H10] (2), also a 16-electron charge-compensated Rh(III) complex. Some reactions of 2 were investigated. At room temperature, in the presence of Na2CO3, it reacts with acetic, methacrylic, and crotonic anhydrides to give the complexes [1,2-μ-{NHC(R)O}-2-PPh3-closo-2,1-RhCB10H10] [R=Me (3), CMeCH2 (4a), and (E)-CHCHMe (4b)], respectively. Benzoyl bromide with 2 and Na2CO3 yields [1,2-μ-{NHC(Ph)O}-2-PPh3-closo-2,1-RhCB10H10] (5). An XRD study of 4a established that the acyl group is coordinated to the rhodium through the oxygen. In the crystal molecules lie pair-wise linked by a BH⇀Rh bridge so that in one molecule the rhodium atom has a 16-electron valence shell and in the other an 18-electron configuration. However, in solution NMR studies reveal that only monomeric molecules occur. With CNBut in the presence of Na2CO3, compound 2 affords [1-NH2-2,2-(CNBut)2-2-PPh3-closo-2,1-RhCB10H10] (7), the structure of which was determined by XRD. The NMR parameters of the new compounds are reported and discussed.

The Mo0 molybdenacarbaborane trianion [1-NH2-2,2,2-(CO)3-closo-2,1-MoCB10H10]3− is formed in situ from the reaction between [7-NH2-nido-7-CB10H10]3− and [Mo(CO)4{NH(CH2)5}2] in THF solution (THF = tetrahydrofuran). In the absence of nitriles, oxidation of this trianion by CH2CHCH2Br gives the MoII complex [1,2-μ-NH2-2,2,2-(CO)3-closo-2,1-MoCB10H10]−, isolated as its [N(PPh3)2]+ salt. However, in the presence of nitriles NCR, the same oxidation ultimately affords the species [N(PPh3)2][1,2-μ-{NHC(R)NH}-2,2,2-(CO)3-closo-2,1-MoCB10H10] in which amidine groups form a bridge between the carbon atom of the cage and the molybdenum, as a consequence of coupling of the nitrile with the cage-bound NH2 group. The acetamidine product [N(PPh3)2][1,2-μ-{NHC(Me)NH}-2,2,2-(CO)3-closo-2,1-MoCB10H10] is also formed by reaction of [7-NH2-nido-7-CB10H12]− with [Mo(CO)6] in refluxing NCMe, and its structure was confirmed by an X-ray diffraction study. Further oxidation of this species by I2 in the presence of CNBut gives the MoIV derivatives [1,2-μ-{NHC(Me)NH}-2,2-(CNBut)2-2-L-2-I-closo-2,1-MoCB10H10] (L = CO, CNBut), of which the tris(isocyanide) complex has been studied by X-ray diffraction.

Treatment of [N(PPh3)2][Fe(CO)2(L)(η5-7-CB10H11)] (L = SMe2, PPh3) in SMe2 or O(CH2)4 with H2SO4 yields the neutral charge-compensated complexes [Fe(CO)2(L)(η5-9-L‘-7-CB10H10)] (L = SMe2, L‘ = SMe2 (2), O(CH2)4 (3); L = PPh3, L‘ = SMe2 (4), O(CH2)4 (5)). An X-ray crystallographic study of 2 established that one of the exopolyhedral SMe2 groups is bonded to a boron in a β-site with respect to the carbon in the ring coordinated to the iron atom. In contrast with these results, the salts [N(PPh3)2][Fe(CO)2(L)(η5-7-CB10H11)] (L = CO, PPh3, CNBut) treated with NCMe and CF3SO3Me afford complexes [Fe(CO)2(L)(η5-9-{(E)-N(Me)C(H)Me}-7-CB10H10)] (L = CO (8), PPh3 (9), CNBut (10)). An X-ray diffraction study on 8 established that the iminium group was attached to a β-B atom of the CB4 iron-bonded ring. Compound 8 is readily hydrolyzed in the presence of a base catalyst affording [Fe(CO)3(η5-9-NH2Me-7-CB10H10)] (12), and with [Na][BH3CN] yields [Fe(CO)3(η5-9-{NH(Me)Et}-7-CB10H10)] (13), the structure of which was det...

In CH2Cl2 solutions, the MoII salt [N(PPh3)2][2,2,2,2-(CO)4-closo-2,1-MoCB10H11] 1 is oxidized by iodine (1 equiv.) in the presence of CNBut (4 equiv.) affording the MoIV complex [2,2,2,2-(CNBut)4-2-I-closo-2,1-MoCB10H11], the structure of which was established by X-ray diffraction. In contrast, under similar conditions the corresponding tungsten salt yields a mixture of [2,2,2-(CNBut)3-2-CO-2-I-closo-2,1-WCB10H11] and [2,2-(CNBut)2-2,2-(CO)2-2-I-closo-2,1-WCB10H11]. Treatment of 1 with iodine in tetrahydrofuran yields the MoII species [N(PPh3)2][2,2,2-(CO)3-2-I-7-{O(CH2)4}-closo-2,1-MoCB10H10], the structure of which was also confirmed by X-ray diffraction. The latter with iodine and S(CH2)4 gives [2,2,2-(CO)3-2-I-3-{S(CH2)4}-11-{O(CH2)4}-closo-2,1-MoCB10H9]. Using CH2Cl2 as solvent, 1 reacts with thioethers L [L = S(CH2)4, cyclo-1,4-S2(CH2)4, cyclo-1,4,7-S3(CH2)6, cyclo-1,4,7,10-S4(CH2)8] and iodine to form [2,2,2-(CO)3-2,3-μ-I-n-L-closo-2,1-MoCB10H9] (isomers, n = 7 and 11) and [2,2,2-(CO)3-2-I-3,11-L2-closo-2,1-MoCB10H9] [except L = cyclo-1,4,7,10-S4(CH2)8]. The molecular structures of [2,2,2-(CO)3-2,3-μ-I-7-{cyclo-1,4,7-S3(CH2)6}-closo-2,1-MoCB10H9] and [2,2,2-(CO)3-2-I-3,11-{cyclo-1,4-S2(CH2)4}2-closo-2,1-MoCB10H9] were determined by X-ray diffraction, confirming both to have doubly B-substituted cages and the former to contain a novel iodide bridge between molybdenum and a cage-boron atom.

Reactions of the salts [N(PPh3)2][2,2,2-(CO)3-2-PPh3-closo-2,1-MCB10H11] (M = Mo or W) with CF3SO3Me or H2SO4 in the presence of donor molecules L afford zwitterionic molecules [2,2,2-(CO)3-2-PPh3-7-L-closo-2,1-MCB10H10] [L = OEt2, O(CH2)4, cyclo-1,4-O(CH2)4O, SMe2, S(CH2)4, cyclo-1,4,7-S3(CH2)6, NCBut or CNC6H3Me2-2,6]. The exopolyhedral group L is attached to a β-boron atom in the CBBBB ring coordinated to the metal, a feature confirmed by an X-ray crystallographic study of [2,2,2-(CO)3-2-PPh3-7-(CNC6H3Me2-2,6)-closo-2,1-MoCB10H10]. The molecules [2,2,2-(CO)3-2-PPh3-7-L-closo-2,1-WCB10H10] [L = OEt2 or O(CH2)4] in THF (tetrahydrofuran) react with Me3NO, with addition of [PPh4]Br, to give the salts [PPh4][2,2,2-(CO)3-2-PPh3-7-R-closo-2,1-WCB10H10] [R = OEt or O(CH2)3CHO]. These products on treatment with CF3SO3Me in CH2Cl2 give the zwitterionic molecules [2,2,2-(CO)3-2-PPh3-7-{O(Me)R}-closo-2,1-WCB10H10] (R = Et or Bun). Single crystal X-ray diffraction studies established the structures of [PPh4][2,2,2-(CO)3-2-PPh3-7-OEt-closo-2,1-WCB10H10] and [2,2,2-(CO)3-2-PPh3-7-{O(Me)Bun}-closo-2,1-WCB10H10]. In NCMe the reagents [N(PPh3)2][2,2,2-(CO)3-2-PPh3-closo-2,1-MCB10H11] react with CF3SO3Me to yield [2,2,2-(CO)3-2-PPh3-7-{N(Me)C(H)Me}-closo-2,1-MCB10H10] (M = Mo or W), compounds in which an imine substituent is bonded to the cage system, a feature confirmed by an X-ray diffraction study of the tungsten species. Similarly, the compounds [N(PPh3)2][2,2,2-(CO)3-2-PPh3-closo-2,1-MCB10H11] react with CNBut and CF3SO3Me to give a mixture of isomers of [2,2,2-(CO)3-2-PPh3-7-{N(But)C(H)Me}-closo-2,1-MCB10H10] (M = Mo or W) with E and Z configurations for the BN(But)C(H)Me group.

Reaction of nine-vertex [closo-1-CB8H9]− with sources of “{M(PEt3)2}+” (M = Rh or Pt) leads to double-cluster metallacarboranes of general formulation [M(PEt3)CB8H9]2, whose gross molecular structu...

In bromobenzene at reflux temperatures the compounds [Os 3 (CO) 12 ] and [N(PPh 3 ) 2 ][ nido -7-CB 10 H 13 ] yield a mixture of the anionic tri- and mono-osmium complexes [Os 3 (CO) 8 (η 5 -7-CB 10 H 11 )] − and [Os(CO) 3 (η 5 -7-CB 10 H 11 )] − , respectively, characterized as their [N(PPh 3 ) 2 ] + salts ( 2b , 3c ). Protonation of 2b with HBF 4 ·Et 2 O in thf (tetrahydrofuran) yields the hydrido cluster complex [Os 3 (μ-H)(CO) 8 (η 5 -7-CB 10 H 11 )] ( 4b ), whilst treatment of 2b in the same solvent with CuCl and PPh 3 in the presence of TlPF 6 affords the bimetallic complex [Os 3 (μ-H)(CO) 8 {η 5 -10-Cu(PPh 3 )-7-CB 10 H 10 }] ( 5b ). In contrast, the compounds [NHMe 3 ][ nido -7-CB 10 H 13 ] and [Os 3 (CO) 12 ] in refluxing bromobenzene give the novel zwitterionic complex [Os(CO) 3 {η 5 -5-(NMe 3 )-7-CB 10 H 10 }] ( 6 ). The structure of 6 was determined by X-ray crystallography, revealing an Os(CO) 3 moiety η 5 -ligated by the carborane cluster in which, unusually, the NMe 3 ligand is bonded to a boron atom on the upper B 5 belt.

The syntheses of the complexes [Y][RuX(L)(PPh3)(η5-7,8-C2B9H11)] (X = Cl, Y = K(18-crown-6), L = CO (1), PPh3 (2); X = I, Y = NEt4, L = CO (3)) are reported, and the structure of 3 has been established by an X-ray diffraction study. The anion adopts the “piano stool” structure with the ruthenium atom η5-coordinated on one side by a nido-7,8-C2B9H11 group and on the other by the CO, PPh3, and I ligands. Treatment of 1 with TlPF6 in THF (tetrahydrofuran) affords solutions of the labile species [Ru(THF)(CO)(PPh3)(η5-7,8-C2B9H11)] (5), which readily react with a 3-fold excess of the monosubstituted alkynes RC⋮CH (R = Ph, But, SiMe3). The product from PhC⋮CH is [Ru(CO)(PPh3)(η2: η5-9-(E)-C(H)C(H)Ph-7,8-C2B9H10)] (8), the structure of which was determined by X-ray crystallography. The metal atom is η5-coordinated by the open face of the nido-7,8-C2B9 cage and also η2-coordinated by the CC bond of the E-C(H)C(H)Ph group, the latter being attached to a boron atom in an α-site with respect to the carbons of the ri...

The [NEt4]+ (1a), [NHMe3]+ (1b), and [N(PPh3)2]+ (1c) salts of the monoanion [Fe(CO)3(η5-7-CB10H11)]- have been prepared via the reaction between [Fe3(CO)12] and [NHMe3][nido-7-CB10H13] in THF (tetrahydrofuran). The complexes [N(PPh3)2][Fe(CO)2(L)(η5-7-CB10H11)] (L = PPh3 (2), CNBut (3)) were obtained by treating 1c in THF with PPh3 and CNBut, respectively, in the presence of Me3NO. The compound [N(PPh3)2][Mo(CO)4(η5-7-CB10H11)] (4) has been synthesized from [Na]3[nido-7-CB10H11] and [Mo(CO)3(NCMe)3] in the presence of CO and with addition of HBF4·Et2O and [N(PPh3)2]Cl. An X-ray diffraction study established that in the anion of 4 the Mo atom is coordinated on one side by the four CO molecules and on the other by a nido-7-CB10H11 carborane in a η5 manner. In reactions with PPh3 and CNBut, the salt 4 gives the species [N(PPh3)2][Mo(CO)3(L)(η5-7-CB10H11)] (L = PPh3 (5a), CNBut (6)). Salts of the anions [Fe(CO)3(η5-7-CB10H11)]- and [Mo(CO)3(PPh3)(η5-7-CB10H11)]- react with donor molecules (THF, OEt2, SMe2) i...

Treatment of Cs[3,3,3-(CO)3-closo-3,1,2-ReC2B9H11] 1 with [Pt(NCMe)2{Ph2P(CH2)2PPh2}][BF4]2 yielded [3,3,3-(CO)3-3,8-(Pt{Ph2P(CH2)2PPh2})-8-(μ-H)-closo-3,1,2-ReC2B9H10][BF4] 2b as the sole product. The cation of salt 2b is a bimetallic species with a Re–Pt bond bridged by a nido-7,8-C2B9H11 ligand pentahapto coordinated to the rhenium and with the β-B–H bond in the ligating CCBBB ring of the carbaborane cage forming a 3-centre 2-electron B–H⇀Pt bond. Deprotonation of 2b with strong bases gives an isomeric mixture of the complexes [3,3,3-(CO)3-3,n-(Pt{Ph2P(CH2)2PPh2})-closo-3,1,2-ReC2B9H10] 3a (n = 4), 3b (n = 8). The isomers are readily separated and the proportion of 3a to 3b formed is solvent- as well as base-dependent. In THF solutions of 2b afford a 1∶3∶1 equilibrium mixture of 2b, 3a, and 3b. Refluxing THF solutions of 1 with [Pt(H)(THF)(PEt3)2][BF4] for several days yields a separable mixture of the isomers [3,3,3-(CO)3-3,n-{Pt(PEt3)2}-closo-3,1,2-ReC2B9H10] 4a (n = 4), 4b (n = 8). The same reactants, when stirred together in CH2Cl2 at ambient temperatures, give 4a and [3,3,3-(CO)3-3,8-{Pt(H)(PEt3)}-8-(μ-H)-closo-3,1,2-ReC2B9H10] 5. Complex 4a, not 5, is the precursor to 4b, the interconversion occurring at elevated temperatures in solution by an intramolecular exchange of B–Pt σ bonds between α-B and β-B vertices in the coordinating CCBBB face of the cage. Treatment of 1 with [Pt(Me)(THF)(PMe2Ph)2][BF4] at room temperature initially gives [3,3,3-(CO)3-3,4-{Pt(PMe2Ph)2}-closo-3,1,2-ReC2B9H10] 6a. However, 6a isomerizes in CH2Cl2 solutions at ambient temperatures to give a 1∶1 mixture of 6a and [3,3,3-(CO)3-3,8-{Pt(PMe2Ph)2}-closo-3,1,2-ReC2B9H10] 6b. The NMR data (1H, 13C, 11B and 31P) for the new complexes are discussed.

Reactions between cationic metal–ligand fragments and salts of the anionic complexes [2,2,2-(CO)3-2-PPh3-closo-2,1-MoCB10H11]− and [2,2-(CO)2-2-L-closo-2,1-FeCB10H11]− (L = CO or PPh3) have afforded a range of zwitterionic compounds in which an electrophilic [ML′n]+ group is attached to the cage system in an exopolyhedral manner by one, two, or three agostic B–H⇀ML′n bonds. The bimetal compounds isolated do not have direct metal–metal bonds, a feature confirmed by X-ray diffraction for [2,2,2-(CO)3-2-PPh3-7,8,12-(μ-H)3-7,8,12-{Cu(PPh3)}-closo-2,1-MoCB10H8], [2,2,2-(CO)3-2-PPh3-7,12-(μ-H)2-7,12-{Ag(PPh3)}-closo-2,1-MoCB10H9], [2,2,2-(CO)3-2-PPh3-7,8,12-(μ-H)3-7,8,12-{RuCl(PPh3)2}-closo-2,1-MoCB10H8] and [2,2,2-(CO)3-2-PPh3-12-(μ-H)-12-{Fe(CO)2(η-C5Me5)}-closo-2,1-MoCB10H10]. The penultimate compound displays in solution complicated dynamic behaviour, in part due to the presence of a number of diastereomeric pairs of enantiomers. Low temperature 31P-{1H} NMR data have helped elucidate these processes for the isomers observed for this complex. The NMR data (1H, 13C, 11B, and 31P) for the new compounds are discussed.

Early studies on organo-transition metal complexes with fluorocarbon ligands are reviewed in a historical context in relation to the renaissance of organometallic chemistry which followed the discovery of ferrocene.

The rhenacarborane salt Cs[Re(CO)3(η5-7,8-C2B9H11)] (1) has been synthesized in excellent yield using a new procedure. Treatment of CH2Cl2 solutions of 1 with [RuCl2(PPh3)3] yields the exo-closo co...

Treatment of THF solutions of [Ru(CO)2(THF)(η5-7,8-C2B9H11)] (2) with K[M(CO)2(η5-C5H5)] followed by addition of 18-crown-6 affords the salts [K(18-crown-6)][MRu(μ-CO)2(CO)2(η5-C5H5)(η5-7,8-C2B9H11)] (3a, M=Fe; 3b, M=Ru). The structure of 3a was established by X-ray diffraction. In the anion of 3a the Fe–Ru bond is symmetrically spanned by two CO groups, and each metal center carries a CO ligand terminally bound in a linear manner. The carbaborane and cyclopentadienyl ligands have a cis disposition with respect to each other. The potassium ion of the [K(18-crown-6)]+ moiety is ligated by an oxygen atom of one of the μ-CO groups. The reaction of 2 with [Rh2(μ-CO)2(η5-C5Me5)2] in THF yields a chromatographically separable mixture of the di- and tri-metal species [RuRh(μ-H)(μ-σ,η5-7,8-C2B9H10)(CO)3(η5-C5Me5)] (4) and [RuRh2(μ-CO)3(μ3-CO)(η5-C5Me5)2(η5-7,8-C2B9H11)] (5). An X-ray diffraction study of 5 revealed a molecular structure based on a triangular array of metal atoms with the Ru atom and the Rh atoms pentahapto coordinated by 7,8-C2B9H11 and C5Me5 ligands, respectively. The metal triangle is symmetrically capped by a CO group. The Rh–Rh bond is symmetrically bridged by a CO ligand, while the two Ru–Rh bonds are each asymmetrically bridged by a CO molecule. The NMR (1H-, 13C{1H}-, and 11B{1H}-) data for the new compounds are reported and discussed in relation to their structures.

Addition of the reagent [Ru(CO)2(thf)(η5-7,8-C2B9H11)] (thf = tetrahydrofuran) to the compounds [M(⋮CC6H4Me-4)(CO)2{κ3-HB(pz)3}] (M = Mo or W, HB(pz)3 = hydrotris(pyrazol-1-yl)borato) in CH2Cl2 affords, respectively, the bimetal species [MRu(μ-CC6H4Me-4)(CO)4(η5-7,8-C2B9H11){κ3-HB(pz)3}] (M = Mo (4a), M = W (4b)). These complexes are readily cleaved by donor molecules, including thf, but they are stable in CH2Cl2 or toluene. X-ray diffraction studies established the molecular structures of 4b and the related species [WRu(μ-CC6H4Me-4)(CO)4(η5-7,8-C2B9H11)(η5-C5H5)] (2b). In both molecules very long Ru−W bonds (ca. 3 A) are asymmetrically bridged by the tolylmethylidyne groups (μ-C−W av 1.92 A, μ-C−Ru av 2.21 A). The complexes 4 react with sulfur or selenium in CH2Cl2 to give the compounds [MRu(μ-1κCα,1:2κE-ECC6H4Me-4)(CO)4(η5-7,8-C2B9H11){κ3-HB(pz)3}] (M = Mo, E = S (6a), Se (6c); M = W, E = S (6b), Se (6d)). The structure of 6b was established by X-ray diffraction. The molecule possesses an unusual struct...

Περίληψη: The alkyne complex [Ru(CO) 2 (MeC,CPh)(η 5 -7,8-C 2 B 9 H 11 ] (3c) has been prepared and its structure determined by X-ray crystallography. The ruthenium is co-ordinated on one side by the nido-7,8-C 2 B 9 H 11 fragment in a pentahapto manner, and on the other by the two CO molecules and the alkyne [Ru–C av. =2.305, C–C=1.228(3) Å. Treatment of 3c with PEt 3 and Ph 2 PCH 2 PPh 2 in CH 2 Cl 2 affords the ylid complexes [Ru{C(Me)C(Ph)PEt 3 }(CO) 2 (η 5 -7,8-C 2 B 9 H 11 )] (4b) and [Ru{C(Me)C(Ph)P(Ph) 2 CH 2 PPh 2 }(CO) 2 (η 5 -7,8-C 2 B 9 H 11 )] (4c), respectively. The structure of 4b was established by an X-ray diffraction study which revealed that the PEt 3 molecule was attached to the carbon atom of the CPh group. In contrast, reactions between 3c and the donor molecules AsPh 3 , SbPh 3 and Ph 2 P(S)CH 2 P(S)Ph 2 resulted in displacement of the alkyne and formation of the complexes [Ru(CO) 2 (L)(η 5 -7,8-C 2 B 9 H 11 )] (5a, L=AsPh 3 ; 5b, L=SbPh 3 ; 5c, L=Ph 2 P(S)CH 2 P(S)Ph 2 ). Treatment of 4c with the Ru(CO) 2 (η 5 -7,8-C 2 B 9 H 11 ) fragment yielded the diruthenium complex [Ru 2 (μ-Ph 2 PCH 2 PPh 2 )(CO) 4 (η 5 -7,8-C 2 B 9 H 11 ) 2 ] (6). The structure, based on the linking of two Ru(CO) 2 (η 5 -7,8-C 2 B 9 H 11 ) groups by the ligand Ph 2 PCH 2 PPh 2 , was determined by X-ray crystallography. NMR data for the new complexes are reported. Παρουσιάστηκε στο: Journal of organometallic chemistry

Reactions between Tl[closo-1,2-Me2-3,1,2-TlC2B9H9] and [RuBr(CO)3(η3-C3H5)] in tetrahydrofuran (THF) affords mixtures of the compounds [Ru(CO)3(η5-7,8-Me2-7,8-C2B9H9)] (1b) and Tl[Ru2(μ-Tl)(CO)4(η5-7,8-Me2-7,8-C2B9H9)2] (2a) in a ratio 2:3. Treatment of the mixtures with [NEt4]I followed by I2 produces [NEt4][RuI(CO)2(η5-7,8-Me2-7,8-C2B9H9)] (3b) as the only product. Complex 2a, isolated as the [NEt4]+ salt 2b, was the subject of a single-crystal X-ray diffraction analysis. The compound crystallises in the orthorhombic space group Pbcn [a=23.164(2), b=13.780(2), c=11.560(6) A]. The structure of the anion consists of two Ru(CO)2(η5-7,8-Me2-7,8-C2B9H9) fragments linked together via a thallium atom, with the complex carrying an overall uninegative charge. The synthon [Ru(THF)(CO)2(η5-7,8-Me2-7,8-C2B9H9)] (4b) is readily generated from 3b by the addition of AgBF4 in THF. The same procedure in MeCN produces the complex [Ru(NCMe)(CO)2(η5-7,8-Me2-7,8-C2B9H9)] (4c). The removal of THF from 4b in vacuo gave the 16-electron complex [Ru(CO)2(η5-7,8-Me2-7,8-C2B9H9)] and a polymeric material postulated to be [Ru(CO)2(η5-7,8-Me2-7,8-C2B9H9)]n. Reaction of solutions of 4b in CH2Cl2 with 2-electron donor ligands yields the complexes [Ru(L)(CO)2(η5-7,8-Me2-7,8-C2B9H9)] (4d, L=PPh3; 4e, L=CNBut; 4f, L=NC5H5). Addition of alkenes and alkynes to CH2Cl2 solutions of 4b did not give stable η2-adducts, but the species [Ru(CO)2(η5-7,8-Me2-7,8-C2B9H9)] was observed in these reactions. The complex [Ru(CO)2(η2,η5-7,8-Me2-10-C(H)C(H)SiMe3-7,8-C2B9H9)] (5a) was isolated from the reaction between 4b and Me3SiCCH. The IR and NMR spectra of the new compounds are reported.

Protonation of [Na][Pt(PMe2Ph)2(η5-7-CB10H11)] 1b with HCl in diethyl ether afforded a mixture of the complexes [PtX(PMe2Ph)2(η5-7-CB10H11)] (X = H 2b or Cl 3) and [Pt2{µ-σ,η5∶σ′,η5′-8,9′-(7-CB10H10)2}(PMe2Ph)4] 4. Single-crystal X-ray diffraction studies established the structures of 3 and 4. In the former the platinum atom is co-ordinated on one side by the open CBBBB face of the nido-7-CB10H11 cage and on the other by a chlorine atom and two PMe2Ph molecules. In the molecule 4 two nido-icosahedral CB10 cage frameworks, each η5-co-ordinated by their open CBBBB faces to a platinum atom, are joined by a B–B connectivity and by two relatively long Pt–B connectivities. The B–B link is formed between a boron atom in a β site in one CBBBB ring and a boron in an α site in the other CBBBB ring. Each boron involved in this connectivity also forms a B–Pt linkage to the platinum atom in the adjacent closo-2,1-PtCB10 sub-cluster. Thus the two metal atoms and the two borons form a ‘butterfly’ arrangement with the platinums at the wing-tips. Treatment of [Na][Pt(PEt3)2(η5-7-CB10H11)] with HCl in diethyl ether gave [PtH(PEt3)2(η5-7-CB10H11)] 2a as expected, but a complex mixture of other products was also formed. Addition of [NEt4]I to this mixture allowed isolation of a species [Pt2(PEt3)4{η5∶η5′-9,9′-I(H)(7-CB10H10)2}] 5. This unusual formulation is based principally on the results of an X-ray diffraction study which revealed that two icosahedral closo-2,1-PtCB10 sub-clusters were bridged by an iodine atom.

The reaction between Na[Pt(PEt3)2(η5-7-CB10H11)] 1 and PhSeCl in thf (tetrahydrofuran) afforded a mixture containing the isomeric species [Pt(SePh)(PEt3)(η5-n-SePh-7-CB10H10)] (n = 8 2a or 9 2b) and the compound [Pt(SePh)(PEt3){η5-8-O(CH2)4Cl-7-CB10H10}] 3. The molecular structures of complexes 2a and 3 were established by X-ray crystallography. Both molecules have Pt(SePh)(PEt3) groups with the platinum atoms pentahapto co-ordinated by nido-7-CB10 cage frameworks. In 2a the cage substituted SePh group is attached to the boron atom in the α site with respect to the carbon in the CBBBB ring ligating the platinum and this is true also of the O(CH2)4Cl substituent in 3. The isomers 2 are also formed when PhSeSePh is used instead of PhSeCl. Treatment of the salt 1 with PhTeI in thf yielded a mixture of [Pt(PEt3)2{η5-9-Te(Ph)CH2Cl-7-CB10H10}] 4 and [Pt2(TePh)(µ-TePh)2(PEt3)2(η5-2-CB10H11)] 5. Single-crystal X-ray diffraction studies were employed to establish the formulations and molecular structures of both molecules. Compound 4 is a charge-compensated platinacarbaborane with a Pt(PEt3)2 group and with the nido-7-CB10 framework carrying a Te(Ph)CH2Cl moiety at the boron vertex situated in the β site with respect to the carbon in the CBBBB ring ligating the platinum. Complex 5 is a diplatinum species in which Pt(TePh)(PEt3) and Pt(PEt3)(η5-2-CB10H11) units are bridged by two TePh groups. The X-ray study revealed that in forming compound 5 from the reagent 1 the nido-7-CB10H11 cage system has undergone an unusual polytopal rearrangement to a nido-2-CB10H11 framework.

Insertion of {M(CO)4} fragments (M = Fe, Ru, Mn, Re) into the eight-vertex monocarborane anion [closo-1-CB7H8]− affords ten-vertex metal–dicarbollide complexes.

The salt [Na][Pt(PEt3)2(η5-7-CB10H11)] (1a) has been prepared. Protonation affords the hydrido complex [PtH(PEt3)2(η5-7-CB10H11)] (2) while reactions with [AuCl(PPh3)], [CuCl(PPh3)]4, and [HgClPh] yield the dimetal compounds [PtM(PEt3)2(PPh3)(η5-7-CB10H11)] (3a, M = Au; 3b, M = Cu) and [PtHgPh(PEt3)2(η5-7-CB10H11)] (3c), respectively. The salt [N(PPh3)2][Pt(CO)(PPh3)(η5-7-CB10H11)] (4) has also been obtained. Single-crystal X-ray diffraction studies have been made on 2 and 3a−c. Complexes 2, 3a, and 3c have similar molecular structures with H, Au(PPh3), and HgPh groups, respectively, σ-bonded to the Pt of the Pt(PEt3)2(η5-7-CB10H11) group. In 3b, however, the copper atom of the Cu(PPh3) moiety is attached to the Pt(PEt3)2(η5-7-CB10H11) fragment both by a Pt−Cu σ-bond and by two exopolyhedral B−H⇀Cu donor bonds from BH groups in the open face of the nido-7-CB10H11 cage ligating the platinum. The structure of the salt 4 has also been determined by X-ray diffraction.

The complex [Ru(THF)(CO)2(η5-7,8-C2B9H11)] (1a, THF = tetrahydrofuran) reacts with the alkylidyne reagents [M(⋮CC6H4Me-4)(CO)2(η5-C5H5)] (M = Mo or W) to give the compounds [MRu(μ-CC6H4Me-4)(CO)4(η5-7,8-C2B9H11)(η5-C5H5)] (M = W (2a), Mo (2b)), which readily isomerize to the species [MRu(CO)4{σ,η5-9-CH(C6H4Me-4)-7,8-C2B9H10}(η5-C5H5)] (M = W (3a), Mo (3b)). The structure of 3b was established by X-ray diffraction. The Mo(CO)2(η5-C5H5) fragment is attached to the closo-RuC2B9 framework by a Mo−Ru bond and a three-center two-electron B−H⇀Mo linkage involving a boron atom in an α site in the CCBBB ring ligating the ruthenium. The CH(C6H4Me-4) moiety bridges between the Ru(CO)2 group and the B atom located in the other α site in the CCBBB ring. The oxo complex [WRuO{μ-σ,η5-9-CH(C6H4Me-4)-7,8-C2B9H10}(CO)2(η5-C5H5)] (4a) is a side product in the formation of 3a, and it also was characterized by X-ray diffraction. Treatment of the species 3 with PMe3 affords the zwitterionic compounds [MRu(CO)4{η5-9-CH(PMe3)(C6...

The compounds [Ru3(CO)12] and nido-7,8-Me2-7,8-C2B9H11 react in CH2Cl2 to yield a mixture of [Ru(CO)3(η5-7,8-Me2-7,8-C2B9H9)] (1b) and [Ru3(CO)8(η5-7,8-Me2-7,8-C2B9H9)] (2) in a ratio of ca. 1:2. The tri- and dinuclear ruthenium complexes [Ru3(μ-H)(μ-σ:η5-7,8-Me2-7,8-C2B9H8)(CO)7(PR3)] (PR3 = PPh3 (3), PCy3 (6)), [Ru3(μ-H)(μ-σ:η5-7,8-Me2-7,8-C2B9H8)(CO)6(PR3)2] (PR3 = PPh3 (4), PMe2Ph (5)), [Ru2(CO)4(PMe3)2(η5-7,8-Me2-7,8-C2B9H9)] (7), and [Ru3(μ-dppm)(CO)6(η5-7,8-Me2-7,8-C2B9H9)] (8) have been prepared by treating 2 with tertiary phosphines. A single-crystal X-ray diffraction study on 5 revealed the structure as one in which a triangular array of ruthenium atoms is bridged by a nido-7,8-Me2-7,8-C2B9H8 group. The latter is pentahapto coordinated to one Ru atom, which carries two CO ligands, and is linked to the other metal atoms by a Ru−B and a B−H⇀Ru bond, respectively. These two ruthenium atoms are each coordinated by two CO groups and one PMe2Ph group. Treatment of 2 with Me2NCH2NMe2 in CH2Cl2 affords ...

The rhodium sandwich complexes [Rh(η6-arene)(η5-7-NHBut-7-CB10H10)] (arene = C6H5Me (2b), C6H3Me3-1,3,5 (3), MeC6H4C6H4Me-4,4‘ (4), [22](1,4)-C16H16 (5)) have been prepared from reactions between 1:1 mol mixtures of the arenes and [RhCl(PPh3)(η5-7-NH2But-7-CB10H10)] (1a) in CH2Cl2 in the presence of AgBF4. The crystal structures of 3 and 5 have been determined by X-ray diffraction confirming that in these species the rhodium is pentahapto coordinated on one side by the formally three-electron-donor 7-NHBut-7-CB10H10 and on the other in the hexahapto manner by a mesitylene molecule and one C6H4 ring of the cyclophane, respectively. The reaction between 4 and [Mo(CO)3(NCMe)3] in THF gave the dirhodium complex [Rh2(CO)2(η5-7-NH2But-7-CB10H10)2] (6), the structure of which has been established by X-ray diffraction. In the molecule two Rh(CO)(η5-7-NH2But-7-CB10H10) fragments are held together by a Rh−Rh bond which is spanned by two B−H⇀Rh two-electron three-center bonds employing in each CBBBB ring ligating a ...

The charge-compensated monocarbon carboranes nido-7-NR3-7-CB10H12 react with [Ru3(CO)12] in toluene at reflux temperatures to give the triruthenium complexes [Ru3(CO)8(η5-7-NR3-7-CB10H10)] [NR3 = NMe3 (1a), NH2But (1b), and NMe2But (1c)]. The molecular structure of 1a has been established by X-ray crystallography. The metal atoms form an essentially isosceles triangle. One Ru atom carries two terminal CO groups and the nido-7-NMe3-7-CB10H10 cage, coordinated in a pentahapto manner. The two boron atoms in the β-sites with respect to the carbon in the CBBBB ring form exopolyhedral three-center, two-electron B−H⇀Ru bonds to the other two Ru atoms. These metal atoms also carry three essentially terminally attached CO ligands. Treatment of 1a with PPh3 in toluene gave, after column chromatography of the mixture, [Ru3(μ-H)(μ3-σ: η5-7-NMe3-7-CB10H9)(CO)7(PPh3)] (2), whereas reaction with CNBut affords [Ru3(CO)7(CNBut)(η5-7-NMe3-7-CB10H10)] (3). The structure of 2 has been established by X-ray crystallography. Th...

Treatment of [Ru(CO)3(η5-7,8-C2B9H11)] (1) with Me3NO in THF (tetrahydrofuran) affords [Ru(CO)2(NMe3)(η5-7,8-C2B9H11)] (3b), while the salt [NEt4][RuI(CO)2(η5-7,8-C2B9H11)] (2) reacts with NCMe in the presence of AgBF4 to give [Ru(CO)2(NCMe)(η5-7,8-C2B9H11)] (3c). Related complexes [Ru(CO)2(L)(η5-7,8-C2B9H11)] (L = CNBut (3d), PPh3 (3e)) are obtained by displacement of THF from [Ru(CO)2(THF)(η5-7,8-C2B9H11)] (3a) with CNBut and PPh3, respectively. Alkenes and 3a afford the complexes [Ru(CO)2(alkene)(η5-7,8-C2B9H11)] (alkene = C2H4 (4a), MeCHCH2 (4b), Me3SiCHCH2 (4c), and C7H10 (norbornene) (4d)), whereas alkynes RC⋮CR (R = Me, Ph) give the species [Ru(CO)2(RC⋮CR)(η5-7,8-C2B9H11)] (R = Me (5a), Ph (5b)). The reaction of complex 5a with K[BH(CHMeEt)3], in Et2O solution, followed by addition of 18-crown-6, gives the salt [K(18-crown-6)][Ru{C(Me)C(H)Me}(CO)2(η5-7,8-C2B9H11)] (6), while PPh3 in CH2Cl2 affords the ylide complex [Ru{C(Me)C(Me)PPh3}(CO)2(η5-7,8-C2B9H11)] (7). Reactions between 3a and the alkynes ...