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Synthesis, bonding and chemistry of mono‐ and bimetallic complexes supported by chelating thiolato ligands have been established. Treatment of [Cp*VCl2]3 (1) with [LiBH4 ⋅ THF] followed by the addition of ethane‐1,2‐dithiol led to the formation of an EPR active bimetallic vanadium thiolato complex [(Cp*V){μ‐(SCH2CH2S)‐κ2S,S′)2{V(SCH2CH2S‐SH)}] (2). In complex 2, two ethane‐1,2‐dithiolato ligands are symmetrically coordinated to two vanadium atoms through μ‐S atoms. Interestingly, when similar reactions were carried out with heavier group 5 metal precursors, such as [Cp*NbCl4] (3 a), it afforded monometallic thiolato complex [Cp*Nb(SCH2CH2S)(SCH2CH2S−CH2S)] (4 a). On the other hand, the Ta‐analogue [Cp*TaCl4] (3 b) yielded thiolato species [Cp*Ta(SCH2CH2S)(SCH2CH2S−CH2S)] (4 b) and [Cp*Ta(SCH2CH2S) (SCH2CH2S−S)] (5). In complexes 4 a and 4 b, one ethane‐1,2‐dithiolato and one trithiolato ligand are coordinated to Nb and Ta centers, respectively. Whereas, in complex 5, one ethane‐1,2‐dithiolato and one 2‐disulfanylethanethiolato is coordinated to the Ta center. Moreover, the photolytic reaction of 5 with [Mo(CO)5 ⋅ THF] yielded heterobimetallic thiolato complex [(Cp*Ta){μ‐(SCH2CH2S)‐κ2S,S′}{μ‐(SCH2CH2S−CH2(CH3)S)κ2S′′ : κ1S‐′′′′ : κ1S′′′′′}{Mo(CO)3}] (6). All the complexes have been characterized by multinuclear NMR spectroscopy and single crystal X‐ray diffraction studies. Further, computational analyses were performed to provide an insight into the bonding of these complexes. [ABSTRACT FROM AUTHOR]

In an effort to synthesize metallaheteroborane clusters of higher nuclearity, the reactivity of metallaheteroboranes, nido-[(Cp*M)2B6S2H4(CS3)] (Cp* = C5Me5) (1: M = Co; 2: M = Rh) with various metal carbonyls have been investigated. Photolysis of nido-1 and nido-2 with group 6 metal carbonyls, M'(CO)5.THF (M' = Mo or W) were performed that led to the formation of a series of adducts [(Cp*M)2B6S2H4(CS3){M'(CO)5}] (3: M = Co, M' = Mo; 4: M = Co, M' = W; 5: M = Rh, M' = Mo; 6: M = Rh, M' = W) instead of cluster expansion reactions. In these adducts, the S atom of C=S group of di(thioboralane)thione {B2CS3} moiety is coordinated to M'(CO)5 (M = Mo or W) in η1-fashion. On the other hand, thermolysis of nido-1 with Ru3(CO)12 yielded one fused metallaheteroborane cluster [{Ru(CO)3}3S{Ru(CO)}{Ru(CO)2}Co2B6SH4(CH2S2){Ru(CO)3}2S], 7. This 20-vertex-fused cluster is composed of two tetrahedral {Ru3S} and {Ru2B2}, a flat butterfly {Ru3S} and one octadecahedron {Co2RuB7S} core with one missing vertex, coordinated to {Ru2SCH2S2} through two boron and one ruthenium atom. On the other hand, the room temperature reaction of nido-2 with Co2(CO)8 produced one 19-vertex fused metallaheteroborane cluster [(Cp*Rh)2B6H4S4{Co(CO)}2{Co(CO)2}2(μ-CO)S{Co(CO)3}2], 8. Cluster 8 contains one nido-decaborane {Rh2B6S2}, one butterfly {Co2S2} and one bicapped square pyramidal {Co6S} unit that exhibits an intercluster fusion with two sulfur atoms in common. Clusters 3–6 have been characterized by multinuclear NMR and IR spectroscopy, mass spectrometry and structurally determined by XRD analyses. Furthermore, the DFT calculations have been carried out to gain insight into electronic, structural and bonding patterns of the synthesized clusters. [ABSTRACT FROM AUTHOR]

In an attempt to isolate boron-containing tri-niobium polychalcogenide species, we have carried out prolonged thermolysis reactions of [Cp*NbCl4] (Cp* = ɳ5-C5Me5) with four equivalents of Li[BH2E3] (E = Se or S). In the case of the heavier chalcogen (Se), the reaction led to the isolation of the tri-niobium cubane-like cluster [(NbCp*)3(μ3-Se)3(BH)(μ-Se)3] (1) and the homocubane-like cluster [(NbCp*)3(μ3-Se)3(μ-Se)3(BH)(μ-Se)] (2). Interestingly, the tri-niobium framework of 1 stabilizes a selenaborate {Se3BH}− ligand. A selenium atom is further introduced between boron and one of the selenium atoms of 1 to yield cluster 2. On the other hand, the reaction with the sulfur-containing borate adduct [LiBH2S3] afforded the trimetallic clusters [(NbCp*)3(μ-S)4{μ-S2(BH)}] (3) and [(NbCp*)3(μ-S)4{μ-S2(S)}] (4). Both clusters 3 and 4 have an Nb3S6 core, which further stabilizes {BH} and mono-sulfur units, respectively, through bi-chalcogen coordination. All of these species were characterized by 11B{1H}, 1H, and 13C{1H} NMR spectroscopy, mass spectrometry, infrared (IR) spectroscopy, and single-crystal X-ray crystallography. Moreover, theoretical investigations revealed that the triangular Nb3 framework is aromatic in nature and plays a vital role in the stabilization of the borate, borane, and chalcogen units. [ABSTRACT FROM AUTHOR]

A series of triborane and tetraborane analogues have been isolated and structurally characterized utilizing chalcogenatoborate ligands Li[BH3(EPh)] (E=S or Se). Thermolysis of [Cp*TaCl4] in the presence of Li[BH3(SPh)] afforded bimetallic tantallaheteroborane [(Cp*Ta)2(μ‐η3:η3‐B2H4S)(μ‐η2:η2‐SBH3)] (1) and hexasulfido trimetallic complex [(Cp*Ta)3(μ‐S)4(μ‐SPh)2] (2). Compound 1 is a fused ditantallaheteroborane, in which both di‐ and triborane analogues are stabilized by two tantalum atoms. In an attempt to synthesize the selenium analogues of 1 and 2, room‐temperature reaction of [Cp*TaCl4] with Li[BH3(SePh)] was carried out, which afforded bimetallic tantallaheteroborane [(Cp*Ta)2{μ‐η3:η3‐B3H6(SePh)}{μ‐SePh}2] (3), monometallic tantallaheteroboranes [Cp*Ta(SePh)2{B4H8‐n(SePh)n}] (4: n=0, 5: n=1), and trimetallic species [(Cp*Ta)3(μ‐Se)4{μ‐Se2(Se)}] (6). Compound 3 is the rarest example of triborane analogue {B3H6(SePh)} in the coordination sphere of two tantalum atoms. Whereas compounds 4 and 5 are examples of unsaturated metallaheteroboranes, in which the tetraborane analogues are stabilized in the coordination sphere of tantalum. One of the unique features of 3 and 5 is the presence of terminal B‐SePh. Compound 6 has similar Ta3Se6 trisbutterfly core as that of 2 with additional bridging selenide unit. All the compounds have been characterized by NMR spectroscopy, mass spectrometry, IR spectroscopy and single‐crystal X‐ray diffraction studies. [ABSTRACT FROM AUTHOR]

Thermolysis of [(Cp*Nb)2(B2H6)2], 1b (Cp* = η5-C5Me5), with 2-mercaptobenzothiazole, C6H4NSCSH (MBT), and 2-mercaptobenzoxazole, C6H4NOCSH (MBO), yielded hydrogen substituted compounds 2 and 3 with a general formula [(Cp*Nb)2(B2H6)(B2H5L)] (2: L = C6H4NSCS and 3: L = C6H4NOCS). A similar reaction of 1b with Ph2Se2 yielded the monosubstituted derivative [(Cp*Nb)2(B2H6){B2H5(PhSe)}], 4. All further efforts towards persubstitution of 1b under various drastic conditions were unfruitful. In parallel, in an effort to find a better synthetic route to the known Ta-aziridine complex [Cp*TaBH(C7H4NS2)CH2S2NC6H4], Cp*TaCl4 was treated with a 2-mercaptobenzothiazolyl-based borate ligand Na[H2B(C6H4NSCS)2]. Surprisingly, the reaction led to the formation of the half-sandwich trichloroaryltantalum(V) complex [Cp*TaCl3{κ2-N,S-C6H4NSCS}], 5, containing a heterocyclic thiol ligand. Using an alternative method complex 5 was isolated in good yield when Cp*TaCl4 was treated with the potassium salt of 2-mercaptobenzothiazole K[C6H4NSCS]. All the compounds were characterized by 1H, 11B{1H}, and 13C{1H} NMR spectroscopy, and their structures were unequivocally established by crystallographic analysis. [ABSTRACT FROM AUTHOR]

Triply-bridging bis-{hydrido(borylene)} and bis-borylene species of groups 6, 8 and 9 transition metals are reported. Mild thermolysis of [Fe2(CO)9] with an in situ produced intermediate, generated from the low-temperature reaction of [Cp*WCl4] (Cp*=η5 -C5Me5) and [LiBH4·THF] afforded triply-bridging bis-{hydrido(borylene)}, [(μ3- BH)2H2{Cp*W(CO)2}2{Fe(CO)2}] (1) and bis-borylene, [(μ3- BH)2{Cp*W(CO)2}2{Fe(CO)3}] (2). The chemical bonding analyses of 1 show that the B H interactions in bis-{hydrido (borylene)} species is stronger as compared to the M H ones. Frontier molecular orbital analysis shows a significantly larger energy gap between the HOMO-LUMO for 2 as compared to 1. In an attempt to synthesize the ruthenium analogue of 1, a similar reaction has been performed with [Ru3(CO)12]. Although we failed to get the bis-{hydrido(borylene)} species, the reaction afforded triply-bridging bis-borylene species [(μ3- BH)2{WCp*(CO)2}2{Ru(CO)3}] (2’), an analogue of 2. In search for the isolation of bridging bis-borylene species of Rh, we have treated [Co2(CO)8] with nido-[(RhCp*)2(B3H7)], which afforded triply-bridging bis-borylene species [(μ3- BH)2(RhCp*)2Co2(CO)4(μ-CO)] (3). All the compounds have been characterized by means of single-crystal X-ray diffraction study; ¹ H, 11B, 13C NMR spectroscopy; IR spectroscopy and mass spectromet [ABSTRACT FROM AUTHOR]

Synthesis of various metal-incorporated bis- and tris-homocubane analogues has been reported. Room temperature reactions of [Cp*MCl2]2 (Cp* = η5-C5Me5, M = Ir or Rh) with chalcogenated borohydride reagents, Li[BH2E3] (E = S or Se), yielded a series of bimetallic bis- and tris-homocubane derivatives (1–7). The bishomocubane analogues belong to the 1,3-bishomocubane family with the general formula [(Cp*M)2(μ-E)2(μ3-E)4(μ3-BH)2] (1: M = Ir, E = S; 2: M = Ir, E = Se; 5: M = Rh, E = S and 6: M = Rh, E = Se), and [(Cp*Ir)2(μ-S)2(μ3-S)4(μ-BH2)2], 3, can be described as an unusual bishomocubane having two (μ-BH2) units with a missing-bond. In addition to these bishomocubanes, two trishomocubane derivatives [(Cp*M)2(μ-E)3(μ3-E)4(μ3-BH)2] (4: M = Ir, E = S and 7: M = Rh, E = Se) were isolated from the above reactions. Trishomocubane 4 adopts a 1,2,4-trishomocubyl structure, whereas 7 is a D3-trishomocubyl analogue. In a similar fashion, thermolysis of [Cp*CoCl]2 with Li[BH2E3] (E = S or Se) led to the formation of Co-1,3-bishomocubane analogues, [(Cp*Co)2(μ-E)2(μ3-E)4(μ3-BH)2] (8: E = S and 9: E = Se). All the compounds were characterized by multinuclear NMR and IR spectroscopies and mass spectrometric analysis. The core geometries of 1–4 and 8 were unequivocally established by single-crystal X-ray diffraction studies. Density functional theory (DFT) computations further demonstrated that metals and chalcogen atoms play an important role in determining the thermodynamic stability of the bis- and tris-homocubane species. [ABSTRACT FROM AUTHOR]

Syntheses and structural elucidations of a series of chalcogen stabilized binuclear complexes of group 5 and 6 transition metals have been described. Room temperature reaction of [Cp*CrCl]2 (Cp* = η5-C5Me5) with Li[BH3(SePh)] afforded a Se inserted binuclear chromium complex, [(Cp*Cr)2(µ-Se2SePh)2], 1. In an attempt to make the analogous complexes with heavier group 6 metals, reactions of [Cp*MCl4] (M = Mo and W) with Li[BH3(SePh)] were carried out that yielded Se inserted binuclear complexes [(Cp*M)2(µ-Se)2(µ-SePh)2], 2 and 3 (2: M = Mo and 3: M = W) along with known [(Cp*M)2B5H9], 4a–b (4a: M = Mo and 4b: M = W). Similarly, the reactions of [Cp*NbCl4] with Li[BH3(EPh)] (E = S or Se) followed by thermolysis led to the formation of binuclear chalcogen complexes [(Cp*Nb)2(µ-E2)2], 5 and 6 (5: E = S and 6: E = Se) and known [(Cp*Nb)2(B2H6)2], 7. All these complexes have been characterized by 1H and 13C NMR spectroscopy and mass spectrometry. The structural integrity of complexes 1, 3, 5 and 6 was established by the X-ray diffraction studies. The DFT studies further exemplify the bonding interactions present in these complexes, especially the multiple bond character between the metals in 1–3. The syntheses and structural characterizations of three chalcogen-bridged bimetallic complexes of group 5 and 6 metals, such as [(Cp*Nb)2(µ-E2)2] (E = S and Se) (right), [(Cp*Cr)2(µ-Se2SePh)2] (centre) and [(Cp*M)2(µ-Se)2(µ-SePh)2], (M = Mo and W) (left) are reported. [ABSTRACT FROM AUTHOR]

In an effort to isolate the chalcogen-rich niobium analogue of [(Cp*Ta)3(μ-S)3(μ3-S)3BH], the room temperature reaction of [Cp*NbCl4] (Cp* = η5-C5Me5) with Li[BH2S3] was carried out. Although the objective of isolating the niobium analogue was not achieved, the reaction yielded a homocubane-type cluster [(Cp*Nb)3(μ-S)3(μ3-S)3(μ-S)BH], 1, and a hexa-sulfido cluster [(Cp*Nb)3(μ-S)6], 2. Cluster 1 is a notable example of a homocubane-type cluster in which one of the vertices of the homocubane is missing. Compound 1 may be considered as a hypo-electronic cluster with an electron count of 64 cve (cve = cluster valence electrons), whereas compound 2 shows the presence of two doubly bridging η1-S around each Nb–Nb bond. On the other hand, the room temperature reaction of [Cp*TaCl4] with selenaborate ligand, [LiBH2Se3], led to the formation of [(Cp*Ta)3(μ-Se)4{μ-Se2(Se2)}], 3. Compound 3 is one of the rarest examples having a Ta3Se6 core structure with a unique diselenide bridging fragment. The presence of a short Se–Se bond of this diselenide unit makes this molecule of further interest. All these compounds were characterized by 1H, 11B{1H} and 13C{1H} NMR spectroscopy, infrared spectroscopy, mass spectrometry, and single-crystal X-ray crystallography. Density functional theory (DFT) calculations were carried out to provide insight into the bonding and electronic structures of these chalcogen-rich trimetallic clusters. [ABSTRACT FROM AUTHOR]

The syntheses and structural characterization of hypo-electronic di-molybdenum triple-decker sandwich clusters are reported. Thermolysis of [Ru3(CO)12] with an in situ generated intermediate obtained from the reaction of [Cp*MoCl4] with [LiBH4·THF] yielded an electron deficient triple-decker sandwich complex, [(Cp*Mo)2{μ–η6:η6-B4H4Ru2(CO)6}], 1. In an effort to generate analogous triple-deckers containing group-16 elements, we isolated [(Cp*Mo)2{μ–η6:η6-B4H4ERu(CO)3}] (3: E = Te; 6: E = S; 7: E = Se). These clusters show a high metal coordination number and cross cluster Mo–Mo bond. The formal cluster electron count of these compounds is four or three skeletal electron pairs less than required for a canonical closo-structure of the same nuclearity. Therefore, these compounds represent a novel class of triple-decker sandwich complex with 22 or 24 valence-electrons (VE), wherein the “chair” like hexagonal middle ring is composed of B, Ru and chalcogen. One of the key differences among the synthesized triple-decker molecules is the puckering nature of the middle ring [B4RuE], which increases in the order S ＜ Se ＜ Ru(CO)3 ＜ Te. In addition, Fenske–Hall and quantum-chemical calculations with DFT methods at the BP86 level of theory have been used to analyze the bonding of these novel complexes. The studies not only explain the electron unsaturation of the molecules, but also reveal the reason for the significant puckering of the middle deck. All the compounds have been characterized by IR, 1H, 11B, and 13C NMR spectroscopy in solution and the solid state structures were established by crystallographic analysis. [ABSTRACT FROM AUTHOR]

Based on benzo[e]indolium and dimesitylborylbenzaldehyde a new ratiometric fluorescent chemodosimeter, C41H43BIN (3) has been synthesized and characterized by 1H, 13C NMR spectroscopy, mass spectrometry and single crystal X-ray crystallography. Probe 3 was found to be highly selective and sensitive toward cyanide (CN−) ions in aqueous medium even in the presence of other competing anions like F−, Cl−, Br−, I−, H2PO4−, HCO3− and AcO−. The detection limit was calculated to be 7.1 × 10−9 M, which is much lower than the maximum permissable concentration in drinking water (1.9 μM) set by the World Health Organization (WHO). In addition, the response time of the probe for CN− is less than 5 seconds. The mechanism is based on a nucleophilic addition reaction of cyanide ions at the polarized [＞C=N＜]+ bond of the benzoindolium group thereby blocking the pi-conjugation between the benzoindolium and triarylborane moiety. This was further confirmed by 1H NMR titration, ESI-MS studies and DFT calculations. [ABSTRACT FROM AUTHOR]

A combined experimental and quantum-chemical study of a series of homometallic metallaheteroboranes [(Cp*M)2E6B2H2] (M = Rh or RuH; E = S or Se; Cp* = η5-C5Me5), which are analogues of 1,3-bishomocubane, is reported. The thermolysis of nido-[(Cp*Rh)2B3H7] ( 1) in the presence of S or Se powder in toluene yielded bishomocubane clusters [(Cp*Rh)2(μ-E)2(μ3-E)4B2H2], ( 3: E = S; 4: E = Se). In a similar fashion, the treatment of nido-[(Cp*RuH)2B3H7] ( 2) with S or Se powder in p-xylene yielded [(Cp*Ru)2(μ-E)2(μ3-E)4B2H2] ( 5: E = S; 6: E = Se) and [(Cp*Ru)2(μ3-Se)(μ4-Se)B3H5] ( 7). One of the noteworthy features of 3- 6 is the presence of an electron-precise trichalcogenoborato ligand. All of the compounds have been characterized by mass spectrometry; IR spectroscopy; and 1H, 11B, and 13C NMR spectroscopy. The structures of 3, 4, 6, and 7 were established unequivocally by X-ray crystallographic analysis. Quantum-chemical calculations by DFT methods for 3, 4, and 6 showed reasonable agreement with the experimentally observed structural parameters. The large HOMO-LUMO gaps are consistent with the high stabilities of these complexes. [ABSTRACT FROM AUTHOR]

Thermolysis of an in situ generated intermediate [(Cp*Ta)2(BH3)2Cl2], 1 generated from the reaction of [Cp*TaCl4], (Cp* = η5-C5Me5) and [LiBH4·thf], in presence of [Ru3(CO)12] yielded pileo-[Cp*TaCl(μ-Cl)-B2H4Ru3(CO)8], 2 having two electrons fewer than seven pairs required for the observed square pyramidal geometry. Cluster 2 is the first example of an unsaturated cluster comprising early and late transition metals in a square pyramid core. This reaction also yielded [(Cp*Ta)2(B2H6)(B2H4Cl2)], 3 as a by-product. In addition, the reaction of [Cp*MoCl4] (Cp* = η5-C5Me5) with [LiBH4.thf] in presence of excess [MeI] at mild condition led to the isolation of periodinated dimolybdatetraborane [(Cp*Mo)2B4H3I5], 4 that hints a possible existence of [(Cp*Mo)2B4H8]. After the isolation of periodinated 4, we extended this chemistry towards the late transition metallaborane [(Cp*Rh)3B4H4], 5 using [PtBr2] as brominating source. Although all the attempts to isolate perbrominated rhodaborane failed, we have isolated partially brominated rhodaborane clusters [(Cp*Rh)3(BH)-(BBr)3], 6 and [(Cp*Rh)3(BH)3(BBr)], 7. All the compounds were characterized by IR and 1H, 11B and 13C NMR spectroscopy in solution, and the solid-state structures of 2, 4 and 6 were established by crystallographic analysis. [ABSTRACT FROM AUTHOR]

The reaction of metal carbonyl compounds with group 6 and 8 metallaboranes led us to report the synthesis and structural characterization of several novel mixed-metal chalcogenide tetrahedral clusters. Thermolysis of arachno-[(Cp*RuCO)2B2H6], 1, and [Os3(CO)12] in the presence of 2-methylthiophene yielded [Cp*Ru(CO)2(μ-H){Os3(CO)9}S], 3, and [Cp*Ru(μ-H){Os3(CO)11}], 4. In a similar fashion, the reaction of [(Cp*Mo)2B5H9], 2, with [Ru3(CO)12] and 2-methylthiophene yielded [Cp*Ru(CO)2(μ-H){Ru3(CO)9}S], 5, and conjuncto-[(Cp*Mo)2B5H8(μ-H){Ru3(CO)9}S], 6. Both compounds 3 and 5 can be described as 50-cve (cluster valence electron) mixed-metal chalcogenide clusters, in which a sulfur atom replaces one of the vertices of the tetrahedral core. Compounds 3 and 5 possess a [M3S] tetrahedral core, in which the sulfur is attached to an exo-metal fragment, unique in the [M3S] metal chalcogenide tetrahedral arrangements. All the compounds have been characterized by mass spectrometry, IR, and 1H, 11B and 13C NMR spectroscopy in solution, and the solid state structures were unequivocally established by crystallographic analysis of compounds 3, 5 and 6. [ABSTRACT FROM AUTHOR]

Chemistry and reactivity of dimolybdathiaborane, [(CpMo)BSH], 1, obtained from the reaction of 2-mercaptobenzothiazole, [CpMoCl] and [LiBH.thf], has been explored with dinuclear metal carbonyl [Fe(CO)]. As a result, reaction of 1 with [Fe(CO)] yielded heterometallathiaborane, [(CpMo)BHSFe(CO)], 2 in good yield. Both the new compounds have been characterized in solution by H, B and C NMR spectroscopy and the structural types were unequivocally established by X-ray crystallographic analysis of compound 2. Cluster 2 has a bicapped octahedral geometry with the {Fe(CO)} fragment occupying one of the high-connectivity cluster vertexes rather than a capping position. Interestingly, cluster 1 undergoes geometric changes (bicapped trigonal bipyramid → bicapped octahedron) on the addition of two-electron {Fe(CO)} fragment to 1. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Synthesis, isolation, and structural characterization of unique metal rich diamagnetic cobaltaborane clusters are reported. They were obtained from reactions of monoborane as well as modified borohydride reagents with cobalt sources. For example, the reaction of [Cp*CoCl]2 with [LiBH4·THF] and subsequent photolysis with excess [BH3·THF] (THF = tetrahydrofuran) at room temperature afforded the 11-vertex tricobaltaborane nido-[(Cp*Co)3B8H10] (1, Cp* = η5-C5Me5). The reaction of Li[BH2S3] with the dicobaltaoctaborane(12) [(Cp*Co)2B6H10] yielded the 10-vertex nido-2,4-[(Cp*Co)2B8H12] cluster (2), extending the library of dicobaltadecaborane(14) analogues. Although cluster 1 adopts a classical 11-vertex-nido-geometry with one cobalt center and four boron atoms forming the open pentagonal face, it disobeys the Polyhedral Skeletal Electron Pair Theory (PSEPT). Compound 2 adopts a perfectly symmetrical 10-vertex-nido framework with a plane of symmetry bisecting the basal boron plane resulting in two {CoB3} units bridged at the base by two boron atoms and possesses the expected electron count. Both compounds were characterized in solution by multinuclear NMR and IR spectroscopies and by mass spectrometry. Single-crystal X-ray diffraction analyses confirmed the structures of the compounds. Additionally, density functional theory (DFT) calculations were performed in order to study and interpret the nature of bonding and electronic structures of these complexes. [ABSTRACT FROM AUTHOR]

Building on our earlier results, the condensation of rhodium polychlorides with borane reagents (LiBH 4 ·thf, BH 3 ·thf, BHCl 2 ·SMe 2 etc.), we continue to explore the chemistry of the same system with metal carbonyl compounds. As a result, the reaction of [(Cp*Rh) 2 B 2 H 6 ], generated from fast metathesis of [Cp*RhCl 2 ] 2 and LiBH 4 , with heavier group 8 metal carbonyl compounds, yielded [(Cp*Rh) 2 B 4 H 4 Rh{Cp*RhB 3 H 8 }], 1 , [(Cp*Rh)B 3 H 7 {Ru(CO) 2 }(Cp*RhCO) 2 ], 2 [(Cp*Rh) 2 B 3 H 3 {Ru(CO) 3 } 2 ], 3 and [(Cp*Rh) 2 {Os 4 (CO) 12 }(B)H], 4 . Further, these reaction also generated two mixed-metal tetrahedral hydrido clusters [(Cp*Rh){Os(CO) 3 } 3 (μ-H) 4 ], 5 and [(Cp*Rh) 2 {Os(CO) 3 } 2 (μ-CO) (μ-H) 2 ], 6 as minor products. Compound 1 is an octahedra and a square pyramid fused cluster, whereas for 2 a square pyramid and a triangle are fused through a vertex. Both 1 and 2 follow Mingos's formalism for fused clusters. Cluster 4 is an interstitial boride composed of one boron, two rhodium and four osmium atoms. Based on its compositions, compound 4 is a rare example of heteronuclear borides. All the compounds have been characterized by IR, 1 H, 11 B, 13 C NMR spectroscopy in solution and the solid state structures were established by crystallographic analysis of 1 – 5 . [ABSTRACT FROM AUTHOR]

• A novel dioxadivanadaborane cluster consisting two μ 3 O units and two terminal persubstituted divanadaborane clusters have been synthesised. • The electronic properties of these complexes has been described. • The experimental results were complemented and rationalized by means of DFT studies. Thermolysis of an in situ generated intermediate which was formed by the reaction of [Cp*VCl 2 ] 3 (Cp* = η5-C 5 Me 5) and LiBH 4. THF with excess of BH 3. THF (THF = tetrahydrofuran) led to the formation of a novel dioxadivandaborane, [(Cp*V) 2 (OBH 3) 2 ], 2 along with divanadaborane [(Cp*V) 2 (B 2 H 6) 2 ], 1. In an attempt to functionalize the terminal B-H vertices by different aryl chalcogenides, 1 was thermolyzed with dinaphthyl diselenide, [Nap 2 Se 2 ] and dimesityl diselenide, [Mes 2 Se 2 ], leading to the formation of persubstituted divanadaboranes, [(Cp*V) 2 {B 2 H 4 (SeNap 2)} 2 ], 3 and [(Cp*V) 2 {B 2 H 4 (SeMes 2)} 2 ], 7. All these compounds were fully characterized with the help of mass spectrometry and 1H, 11B{1H} and 13C{1H} NMR spectroscopy and the dioxadivandaborane species 2 was additionally characterized by X-ray diffraction analysis. Density Functional Theory (DFT) calculations show geometries in agreement with the structural determinations. The reduction in the HOMO-LUMO gap due to the introduction of chalcogenide ligands in 2, 3 and 7 is in respectable agreement with their UV–Vis absorption spectra. [Display omitted] [ABSTRACT FROM AUTHOR]

Photolysis of [{(μ3-BH)(Cp*Ru)Fe(CO)3}2(μ-CO)] (1; Cp* = η5-C5Me5) in the presence of various alkynessuch as 1,2-diphenylethyne, 1-phenyl-1-propyne, 2-butyne, and 1-(diphenylphosphino)-2-phenylacetyleneled to the formation of four types of novel heterometallic metallacarboranes,[1,1,1-(CO)3-μ-2,3-(CO)-2,3-(Cp*)2-4,6-Ph2-closo-1,2,3,4,6-FeRu2C2BH] (2), [1,8-(Cp*)2-2,2,7,7-(CO)4-μ-2,8-(CO)-μ-7,8-(CO)-4-Me-5-Ph-pileo-1,2,7,4,5-RuFe2C2(BH)2] (3), [1,8-(Cp*)2-2,2,7,7-(CO)4-μ-2,8-(CO)-μ-7,8-(CO)-4,5-Me2-pileo-1,2,7,4,5-RuFe2C2(BH)2] (4), and [1,2-(Cp*)2-6,6,7,7-(CO)4-μ-2,7-(CO)-exo-μ-5,6-(PPh2)-μ3-1,2,6-(BH)-4-Ph-pileo-1,2,6,7,4,5-Ru2Fe2C2BH] (5). Cluster compound 2exhibits an octahedralstructure with adjacent carbon atoms consistent with its skeletalelectron pair (sep) count of 7. The cage geometry of 3and 4is based on a pentagonal bipyramid with one additional{Cp*Ru} vertex capping one of its faces. The solid-state X-ray diffractionresults of 5suggest that the core geometry is a cappedpentagonal bipyramid, with an Fe–C bridging PPh2group. All the cluster compounds 2–5have been characterized by IR and 1H, 11B,and 13C NMR spectroscopy, and the geometries of the structureswere unequivocally established by crystallographic analysis. [ABSTRACT FROM AUTHOR]

Abstract: Treatment of group 5 metal polychlorides such as, [CpnMCl4-x] (M = V: n, x = 2; M = Nb: n = 1, x = 0), or [Cp∗TaCl4] (Cp = η5–C5H5, Cp∗ = η5-C5Me5), with [LiBH4·THF] followed by thermolysis in the presence of diphenyl diselenide yielded metallaheteroborane clusters [{CpV(μ-SePh)}2(μ-Se)], 1 [(CpNb)2B4H9(μ-SePh)], 2 and [(Cp∗Ta)2B4H11(SePh)], 3 in modest yields. Compound 1 is an organovanadium selenolato cluster in which two (CpV) moieties bridged by (μ-Se) and two (μ-SePh) ligands. Compound 2 exhibits a bicapped tetrahedral core with one (μ-SePh) ligand. 3 is a tantalahexaborane cluster in which one of the terminal BH protons is substituted by SePh. Compounds 1–3 have been characterized by mass spectrometry, 1H, 11B, 13C NMR spectroscopy, and the geometric structures were unequivocally established by crystallographic analysis of 1–3. [Copyright &y& Elsevier]

Abstract: Chalcogen-stabilized dimolybdaboranes 3–5 (3: [(Cp∗Mo)2B4H5Se(Ph)], 4: [(Cp∗Mo)2B4H3Se2(SeCH2Ph)] and 5: [(Cp∗Mo)2B3H6(BSR)(μ-η1-SR)] (R=2,6-( t Bu)2-C6H2OH)) have been isolated from the mild pyrolysis of dichalcogenide ligands, RE-E‘R (R=Ph: E=S, E‘=Se; R=CH2Ph, [2,6-( t Bu)2-C6H2OH]: E=E‘=Se, S) and [(Cp∗Mo)2B4H8], 2, an intermediate generated from the reaction of [Cp∗MoCl4] (1) (Cp∗ =η5-C5Me5), with [LiBH4.thf]. The geometry of [(Cp∗Mo)2B4H5Se(Ph)] is similar to that of [(Cp∗Mo)2B5H9], in which one BH3 unit on the open face is replaced by a triple bridged selenium atom. All the compounds have been characterized in solution by 1H, 11B, 13C NMR and IR spectroscopy and elemental analysis. The structural types were unequivocally established by X-ray crystallographic analysis of compounds 3–5. [Copyright &y& Elsevier]

Abstract: Pyrolysis of an in-situ generated intermediate, produced in the reaction of [Cp∗MoCl4], 1, (Cp∗ =η5-C5Me5) with [LiBH4·THF], with an excess of difuryl ditelluride in toluene at 90°C yielded syn and anti isomers of [Cp∗Mo(O)(μ-Te)]2 (2, 3) and [Cp∗ 2Mo2O2(μ-O)(μ-Te)] (4, 5). In a similar fashion, dibenzyl diselenide yielded syn and anti isomers of [Cp∗Mo(O)(μ-Se)]2 (6, 7), along with the known nido-[(Cp∗Mo)2B4H8Se2]. Note that in parallel with 2–7, [(Cp∗Mo)2B5H9] was isolated as the major product in both cases. Compounds 2–7 have been isolated in modest yield as orange to brown crystalline solids. All the new compounds have been characterized in solution by mass, IR, 1H, 13C, 77Se and 125Te NMR spectroscopy, and the structural types were unequivocally established by crystallographic analysis of 2–4 and 7. [Copyright &y& Elsevier]

Abstract: Reaction of [(CpV)2(B2H6)2], 1 (Cp=η5-C5H5) with four equivalents of [Co2(CO)8] or [Co4(CO)12] in hexane at 70°C leads to the isolation of the tetranuclear carbonyl cluster, [(η6-C6H5OCo)Co3(CO)9], 2 in modest yield. The geometry of 2 is similar to that of [Co4(CO)12] where all the four Co atoms are arranged in a tetrahedral geometry. The apical cobalt atom in 2 is coordinated to C6H5O ring in a η6-fashion and the other three cobalt atoms are each coordinated to three carbonyl ligands. Compound 2 has been characterized in solution by IR, 1H, 13C NMR and mass spectrometry and the structural types were unequivocally established by crystallographic analysis. [ABSTRACT FROM AUTHOR]

A new structural analogue of nido -homobimetallahexaborane(10), nido -[3,6-{(OC) 3 Mn} 2 (B 4 H 8 ·THF)], 1 is synthesized (see picture). • Bimtellahexaborane(10) analogue, nido -[3,6-{(OC) 3 Mn} 2 (B 4 H 8 ·thf)], 1 is synthesised. • 1 is a novel homometallic M 2 B 4 cluster known without a M−M bond. • Theoretical calculation indicated the higher relative thermodynamic stability for 1. • Reaction of nido -[1,2-(Cp*Ru) 2 (µ -H)B 4 H 9 ] with borane led to cluster build-up. Cluster nido -[3,6-{(OC) 3 Mn} 2 (B 4 H 8 ·THF)], 1 , (THF = tetrahydrofuran), has been synthesized from the irradiation of [Mn 2 (CO) 10 ] with [BH 3 ·THF] at 255 nm along with [{(OC) 4 Mn}(η 6-B 2 H 6){Mn(CO) 3 } 2 (µ -H)], 2. Cluster 1 represents the new structural analogue of nido -homobimetallahexaborane(10) where the metal centers are arranged symmetrically in the non-adjacent basal positions of a pentagonal pyramid core. Theoretical calculation suggests that nido- 1 is thermodynamically more stable as compared to the other hypothetical possible isomer nido -[4,5-{(OC) 3 Mn} 2 (B 4 H 8 ·THF)], II. Further, the reactivity of another homobimetallahexborane(10), nido -[1,2-(Cp*Ru) 2 (µ -H)B 4 H 9 ], 3 has been explored with borane that led to cluster build-up reaction to yield bimetallaoctaborane(12) analogues, nido -[(Cp*Ru) 2 B 6 H 10 (OH) 2 ], 4 and nido -[(Cp*Ru) 2 B 6 H 11 (OH)], 5. All the clusters have been characterized by multinuclear NMR and IR spectroscopies as well as by mass spectrometric analysis. The structural types of 1 and 4 were unequivocally established by crystallographic analysis. [ABSTRACT FROM AUTHOR]

The syntheses and structural characterization of hypo-electronic di-molybdenum triple-decker sandwich clusters are reported. Thermolysis of [Ru3(CO)12] with an in situ generated intermediate obtained from the reaction of [Cp*MoCl4] with [LiBH4·THF] yielded an electron deficient triple-decker sandwich complex, [(Cp*Mo)2{μ–η6:η6-B4H4Ru2(CO)6}], 1. In an effort to generate analogous triple-deckers containing group-16 elements, we isolated [(Cp*Mo)2{μ–η6:η6-B4H4ERu(CO)3}] (3: E = Te; 6: E = S; 7: E = Se). These clusters show a high metal coordination number and cross cluster Mo–Mo bond. The formal cluster electron count of these compounds is four or three skeletal electron pairs less than required for a canonical closo-structure of the same nuclearity. Therefore, these compounds represent a novel class of triple-decker sandwich complex with 22 or 24 valence-electrons (VE), wherein the “chair” like hexagonal middle ring is composed of B, Ru and chalcogen. One of the key differences among the synthesized triple-decker molecules is the puckering nature of the middle ring [B4RuE], which increases in the order S ＜ Se ＜ Ru(CO)3 ＜ Te. In addition, Fenske–Hall and quantum-chemical calculations with DFT methods at the BP86 level of theory have been used to analyze the bonding of these novel complexes. The studies not only explain the electron unsaturation of the molecules, but also reveal the reason for the significant puckering of the middle deck. All the compounds have been characterized by IR, 1H, 11B, and 13C NMR spectroscopy in solution and the solid state structures were established by crystallographic analysis. [ABSTRACT FROM AUTHOR]

Thermolysis of an in situ generated intermediate [(Cp*Ta)2(BH3)2Cl2], 1 generated from the reaction of [Cp*TaCl4], (Cp* = η5-C5Me5) and [LiBH4·thf], in presence of [Ru3(CO)12] yielded pileo-[Cp*TaCl(μ-Cl)-B2H4Ru3(CO)8], 2 having two electrons fewer than seven pairs required for the observed square pyramidal geometry. Cluster 2 is the first example of an unsaturated cluster comprising early and late transition metals in a square pyramid core. This reaction also yielded [(Cp*Ta)2(B2H6)(B2H4Cl2)], 3 as a by-product. In addition, the reaction of [Cp*MoCl4] (Cp* = η5-C5Me5) with [LiBH4.thf] in presence of excess [MeI] at mild condition led to the isolation of periodinated dimolybdatetraborane [(Cp*Mo)2B4H3I5], 4 that hints a possible existence of [(Cp*Mo)2B4H8]. After the isolation of periodinated 4, we extended this chemistry towards the late transition metallaborane [(Cp*Rh)3B4H4], 5 using [PtBr2] as brominating source. Although all the attempts to isolate perbrominated rhodaborane failed, we have isolated partially brominated rhodaborane clusters [(Cp*Rh)3(BH)-(BBr)3], 6 and [(Cp*Rh)3(BH)3(BBr)], 7. All the compounds were characterized by IR and 1H, 11B and 13C NMR spectroscopy in solution, and the solid-state structures of 2, 4 and 6 were established by crystallographic analysis. [ABSTRACT FROM AUTHOR]

We have synthesized and structurally characterized two new borate complexes of early transition metals utilizing chalcogen based borate ligand Li[BH 3 (SPh)]. [Display omitted] • Two unique chalcogen stabilized borate complexes of Ta were isolated. • Complex 1 has two unique borate ligands, i.e., {BH 3 (SPh)} and {BH 3 (S)}. • Compound 2 has another unique borate ligand {BH 3 (C 6 H 4)S} and triborane analog. • The DFT calculations revealed the σ-donation of B-H bonds of borates to Ta atoms. In an attempt to isolate some electron precise early transition metal borate complexes, we have explored the reactions of [Cp*TaCl 4 ] (Cp* = η 5-C 5 Me 5) with chalcogen-based borate ligand Li[BH 3 (SPh)]. The room-temperature reaction yielded bimetallic borate complex [(Cp*Ta) 2 (μ -SPh){S(BH 3)}{SPh(BH 3)}] (1) that present two types of borate ligands, i.e., {BH 3 (SPh)} and {BH 3 (S)} ligands having unique coordination with the tantalum atoms. Interestingly, the {BH 3 (S)} ligand is coordinated to both the Ta centers in µ-η1:η2 fashion. On the other hand, thermolysis of [Cp*TaCl 4 ] in the presence of Li[BH 3 (SPh)] yielded a bimetallic borate species [(Cp*Ta) 2 (µ - η 3: η 3-B 2 H 4 S){ µ - η 2: η 2-S(C 6 H 4)BH 3 }] (2). Compound 2 contains a triborane analog and a borate ligand, which are coordinated to two Ta atoms. This can also be considered as a notable example of C H activated molecule, in which a B-C bond formation took place. Both the borate species have been characterized by mass spectrometry, IR spectroscopy, NMR spectroscopy, and single-crystal X-ray diffraction studies. The density functional theory (DFT) calculations further provided insights into the bonding and electronic structures of these bimetallic borate species. [ABSTRACT FROM AUTHOR]

Syntheses and structural characterization of supraicosahedral rhodaborane clusters are reported. Reaction of [(Cp*RhCl2)2], (Cp* = η5-C5Me5) with [LiBH4·thf] followed by thermolysis with excess of [BH3·thf] afforded 16-vertex closo-[(Cp*Rh)3B12H12Rh{Cp*RhB4H9}], 1, 15-vertex [(Cp*Rh)2B13H13], 2, 12-vertex [(Cp*Rh)2B10Hn(OH)m], (3a: n = 12, m = 0; 3b: n = 9, m = 1; 3c: n = 8, m = 2) and 10-vertex [(Cp*Rh)3B7H7], 4, and [(Cp*Rh)4B6H6], 5. Cluster 1 is the unprecedented 16-vertex cluster, consists of a sixteen-vertex {Rh4B12} with an exo-polyhedral {RhB4} moiety. Cluster 2 is the first example of a carbon free 15-vertex supraicosahedral metallaborane, exhibits icosihexahedron geometry (26 triangular faces) with three degree-six vertices. Clusters 3a-c have 12-vertex isocloso geometry, different from that of icosahedral one. Clusters 4 and 5 are attributed to the 10-vertex isocloso geometry based on 10-vertex bicapped square antiprism structure. In addition, quantum-chemical calculations with DFT methods at the BP86 level of theory have been used to provide further insight into the electronic structure and stability of the optimized structures which are in satisfactory agreement with the structure determinations. All the compounds have been characterized by IR, 1H, 11B, 13C NMR spectroscopy in solution, and the solid state structures were established by crystallographic analysis of compounds 1-5. [ABSTRACT FROM AUTHOR]

Density functional theory (DFT) has been used to probe the bonding and electronic properties of dimolybdaborane [(Cp*Mo)2B5H9], 1 (Cp* = n²-C5Me5), and several other hetero-dimolybdaborane clusters, such as [(Cp*Mo)²B5(μ3-OEt)H7] (2), [(Cp*Mo)2B5(μ3-OEt)(n-BuO)H6] (3), [(n²-C5H5W)2B4H4S2] (4), and [(Cp*Mo)2B4H4E2 (5-7, where, for 5, E = S, for 6, E = Se, and for 7, E = Te). The DFT results were also used to address some key points such as (i) the metal--metal bond length, (ii) the location and number of bridging and terminal hydrogen atoms, (in) the molecular orbital analysis, and (iv) the assignment of 11B and ¹H NMR chemical shifts. These studies further provide meticulous insight into similarities and differences between various dimetallaborane dusters 1--7. In addition, the crystal structures of 5 and 7 are reported, which come on top of the already existing literature of dimetallaboranes and support the theoretical findings. [ABSTRACT FROM AUTHOR]

Mild thermolysis of tantalaborane [(Cp*Ta)2BsH11], 1 (Cp* = π5-C5Me5) in presence of halogen sources affords the open cage clusters [(Cp*TaX)2B5H11], 2-4 (2: X = CI; 3: X = Br; and 4: X =I) in good yields. In contrast, the tetraborohydride cluster, [(Cp*Ta)2B4H9(μ-BH4)], 5, under the same reaction conditions forms the B--H substituted cluster [(Cp*Ta)2B4H8I(μ-BH4)], 6. All the new metallaboranes have been characterized by mass spectrometry, ¹H, 11B, 13C NMR spectroscopy, and elemental analysis, and the structural types were established by crystallographic analysis of clusters 3, 4, and 6. Density functional theory (DFT) calculations at the BP86/TZ2P ZORA level reveal geometries in agreement with the structure determinations, large gaps between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) in accord with their stabilities. B3LYP-computed 11B chemical shifts accurately reflect the experimentally measured shifts. Clusters 2--4 can be viewed as 7-sep 7-vertex oblatoarachno M2B5 clusters which can be generated from a 7-sep 9-vertex oblatocloso M2B7 cluster by removal of two equatorial boron atoms. Cluster 6 can be considered as an electron-deficient 6-sep 6-vertex oblatoarachno M2B4 cluster derived from an 8-vertex oblatocloso hexagonal bipyramidal duster, in which BH4_ anion is weakly bonded in a bidentate mode. [ABSTRACT FROM AUTHOR]

The reaction of [(Cp*Ta)2B4H9(μ-BH4)] (1; Cp* = η5-C5Me5) with [Fe2(CO)9] in hexane yielded [(Cp*Ta)2B5H7{Fe(CO)3}2] (2) and [(Cp*Ta)2B5H9{Fe(CO)3}4] (3) in moderate yield. Cluster 2 represents the first example of a bicapped pentagonal-bipyramidal metallaborane with a deformed equatorial plane, and 3 can be described as a fused cluster in which two pentagonal-bipyramidal units are fused through a common 3-vertex triangular face. Compounds 2 and 3 have been characterized by mass spectrometry and IR, 1H, 11B, and 13C NMR spectroscopy, and the geometric structures were unequivocally established by crystallographic analysis. [ABSTRACT FROM AUTHOR]

Abstract: Mono and doubly alkynyl substituted ferrocene complexes, [Fc(CH2OCH2Calic> n ], 2–3 (2: n =1; 3: n =2; Fc=ferrocene) have been synthesized from the room temperature reaction of mono and 1,1′-dihydroxymethyl ferrocene, Fc(CH2OH) n , 1a–b (1a: n =1; 1b: n =2) and propargyl bromide, in modest to good yields. These new ferrocene derivatives have been characterized by mass, IR, 1H, 13C NMR spectroscopy, and molecular structures of compound 2 and 3 were unequivocally established by single crystal X-ray diffraction study. The crystal structure analysis revealed that 2 and 3 consist of infinite 1D zig-zag hydrogen bonded chains and 2D microporous hydrogen bonded network of molecules, linked by intermolecular C–H···O hydrogen bonding. The molecular structures of both 2 and 3 are further stabilized by C–H···π interactions. [Copyright &y& Elsevier]

Vanadaborane, [(CpV)2(B2H6)2] (Cp = η5-C5H5), 1 reacts with elemental sulfur to afford the hexasulfide cluster [(CpV)2S4(μ-η1-S2)], 2 in high yield. Compound 2 is a notable example of an organovanadium sulfide cluster in which the [V2S4] atoms define a bicapped tetrahedron framework, with one μ-η1-S2 ligand bridged the two (CpV) moieties. The sulfur atom in [V2S4] core in 2 is a four-skeletal-electron donor isoelectronic with the BH3 unit; therefore, the replacement of boron hydride in 1 by four sulfur atoms necessitates the formation of a bicapped tetrahedron [V2S4] framework. Furthermore, this is the only reported example of a bimetallic hexasulfide cluster containing vanadium. Pyrolysis of 1 with bis-chalcogenide ligands such as Ph2S2 and Bz2Se2 (Bz = PhCH2), results in the formation of substituted vanadahexaboranes [(CpV)2B4H12-xLx], 3-5 (3: L = SPh: x = 3; 4: L = SPh, x = 2; 5: L = SeBz: x = 1) in modest yield. All these new compounds have been characterized by mass, 1H, 11B, 13C NMR spectroscopy, and elemental analysis, and the structural types were unequivocally established by crystallographic analysis of compounds 2-5. [ABSTRACT FROM AUTHOR]

Abstract: Reaction of (η5-C5Me5)MoCl4 with 6-fold excess of LiBH4·thf followed by pyrolysis with BHCl2·SMe2 in toluene at 90°C yielded known (η5-C5Me5Mo)2B5H9 (1) and B-Cl inserted (η5-C5Me5Mo)2B5H8Cl (2), (η5-C5Me5Mo)2B5H7Cl2 (3–5, three isomers) and (η5-C5Me5Mo)2B5H5Cl4 (6). In addition, reaction of (η5-C5Me5Mo)2B5H9 with 5-fold excess of n-BuLi followed by excess of MeI in THF yielded B-Me inserted metallaboranes (η5-C5Me5Mo)2B5H7(CH3)2 (7, 8 two isomers) and (η5-C5Me5Mo)2B5H6(CH3)3 (9, 10 two isomers). Isolated yields of 2–6 are poor but 7–10 are modest to good. Compounds 2–10 can be viewed as bicapped closo trigonal bipyramidal geometry. All the new compounds have been characterized in solution by IR, 1H, 11B, 13C NMR and mass spectroscopy as simple substitution derivatives of (η5-C5Me5Mo)2B5H9 and the structural types were unequivocally established by crystallographic analysis of compounds 2, 3, 5 and 6. [Copyright &y& Elsevier]

The reactions of the germylenes, [(Dipp)NCMeCHCORGeCl] (1a : R = Me, 1b : R = Ph) with [Ir 2 Cl 2 (μ -Cl) 2 (η 5-Cp*) 2 led to the formation of the adducts [(Dipp)NCMeCHCORGeClIrCl 2 Cp*] (3a : R = Me and 3b : R = Ph). On the other hand, [Rh 2 Cl 2 (μ -Cl) 2 (η 5-Cp*) 2 does not react with the germylenes (1a and 1b). When the reactions of 1a and 1b are carried out with [Cp*TaCl 4 , the reaction led to decomposition. The reaction of 1a or 1b with TaCl 5 yielded the transmetallated products [(Dipp)NCMeCHCORTaCl 4 (4a : R = Me, 4b : R = Ph) with the extrusion of GeCl 2. Our theoretical studies show that for, the insertion of TaCl 5 to 1a and the formation of 4a with concomitant elimination of GeCl 2 is energetically favourable. Extrusion of SnCl 2 is also observed when the corresponding stannylene, [(Dipp)NCMeCHCOMeSnCl] was reacted with TaCl 5. All these compounds have been characterized by 1H and 13C NMR spectroscopy, elemental analysis and the constitution of compounds 1b , 3b, and 4a were confirmed by single-crystal X-ray crystallography. Image 1 • This manuscript reports the first example of N,O-chelated germanium adduct with a transition metal. • We have reported the synthesis of transmetallated Ta-complex using ketiminate-germylene chlorides and stannylene chlorides. • The formation of transmetallated and adduct products were established by DFT analysis. [ABSTRACT FROM AUTHOR]