Rajendra Singh Dhayal

Indian Institute of Technology Madras, Chennai, State of Tamil Nadu, India

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Publications (12)35.79 Total impact

  • [show abstract] [hide abstract]
    ABSTRACT: An unprecedented air-stable, nanospheric polyhydrido copper cluster [Cu20(H)11(S2P(OiPr)2)9] (1H), which is the first example of elongated triangular orthobicupola copper atom array of C3h symmetry, was synthesized and characterized. Its composition is primarily determined by ESI mass spectrometry, and fully characterized by NMR (1H, 2H and 31P), and single crystal X-ray diffraction. The structure of complex 1H can be expressed by a trigonal-bipyramidal unit of [Cu2H5]3- anchored within an elongated triangular orthobicupola polyhedron of eighteen copper atoms, which is further stabilized by eighteen sulphur atoms from nine dithiophosphate ligands and six capping hydrides. The positions of eleven hydrides revealed from the low temperature X-ray diffraction was supported by a density functional theory (DFT) investigation on a simplified model [Cu20H11(S2PH2)9] of C3h symmetry. 1H is capable of releasing H2 gas under irradiation of sunlight, mild thermal condition (at 65 oC), or in the presence of acids at RT.
    Journal of the American Chemical Society 03/2013; · 10.68 Impact Factor
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    ABSTRACT: Two luminescent, undecanuclear silver complexes [Ag(11)(μ(9)-I)(μ(3)-I)(3){E(2)P(O(i)Pr)(2)}(6)](PF(6)) [E = S (yellow), 1; Se (orange), 2], containing the first μ(9)-iodine inscribed at the center of a pentacapped trigonal-prismatic silver skeleton, were reported.
    Inorganic Chemistry 06/2012; 51(14):7439-41. · 4.59 Impact Factor
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    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.
    Polyhedron 04/2011; 30(6):1048–1054. · 1.81 Impact Factor
  • Rajendra Singh Dhayal, V. Ramkumar, Sundargopal Ghosh
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    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-(tBu)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-(tBu)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.
    Polyhedron 01/2011; 30(12):2062-2066. · 1.81 Impact Factor
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    ABSTRACT: Reaction of [Cp*MoCl(4)], 1 (Cp* = eta(5)-C(5)Me(5)), with [LiBH(4).thf] in toluene at -70 degrees C, followed by pyrolysis with excess dichalcogenides RE-ER (R = Ph, CH(2)Ph, 2,6-((t)Bu)(2)-C(6)H(2)OH, (CH(3))(3)C = (t)Bu); E = S, Se) yielded a new class of hybrid clusters, 3-8: (3, [(Cp*Mo)(2)(mu-eta(1)-SPh)(2)(mu(3)-S)(H(2)BSPh)]; 4, [(Cp*Mo)(2)B(5)H(8)(SPh)]; 5, [(Cp*Mo)(2)B(5)H(8)(SePh)]; 6, [(Cp*Mo)(2)B(2)S(2)H(2)(mu-eta(1)-S)]; 7, [(Cp*Mo)(2)B(2)H(5)(BSR)(2)(mu-eta(1)-SR)], (R = 2,6-((t)Bu)(2)-C(6)H(2)OH); and 8, [(Cp*Mo)(2)B(2)H(5)(BSePh)(2)(mu-eta(1)-SePh)]. Compounds 3-8 have been isolated in modest yields as green or brown crystalline solids. In parallel with 3-8, [(Cp*Mo)(2)B(5)H(9)] was isolated as a major product in all cases. The isolation and structural characterization of compounds 3 and 6-8 provided the first direct evidence of the existence of [(Cp*Mo)(2)B(4)H(8)], 2, an intermediate in the formation of [(Cp*Mo)(2)B(5)H(9)]. These new compounds have been characterized in solution by mass spectrometry, (1)H, (11)B, (13)C NMR, and IR spectroscopy, and elemental analysis. The structural types were unequivocally established by X-ray crystallographic analysis of compounds 3-8.
    Inorganic Chemistry 09/2010; 49(17):7741-7. · 4.59 Impact Factor
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    ABSTRACT: The reaction of the [(eta(5)-C(5)Me(5))MoCl(4)] complex with [LiBH(4).THF] in toluene at -70 degrees C, followed by pyrolysis at 110 degrees C, afforded dark brown [(eta(5)-C(5)Me(5)Mo)(3)MoB(9)H(18)], 2, in parallel with the known [(eta(5)-C(5)Me(5)Mo)(2)B(5)H(9)], 1. Compound 2 has been characterized in solution by (1)H, (11)B, and (13)C NMR spectroscopy and elemental analysis, and the structural types were unequivocally established by crystallographic studies. The title compound represents a novel class of vertex-fused clusters in which a Mo atom has been fused in a perpendicular fashion between two molybdaborane clusters. Electronic structure calculations employing density functional theory yield geometries in agreement with the structure determinations, and on grounds of density functional theory calculations, we have analyzed the bonding patterns in the structure.
    Inorganic Chemistry 02/2010; 49(3):900-4. · 4.59 Impact Factor
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    ABSTRACT: The reaction of [(η5-C5Me5)MoCl4] with [LiBH4·THF] in toluene at -70°, followed by pyrolysis at 110°, afforded dark brown [(η5-C5Me5Mo)3MoB9H18], 2, in parallel with the known [(η5-C5Me5Mo)2B5H9], 1. Compd. 2 was characterized in soln. by 1H, 11B, and 13C NMR spectroscopy and elemental anal., and the structural types were unequivocally established by crystallog. studies. The title compd. represents a novel class of vertex-fused clusters in which a Mo atom was fused in a perpendicular fashion between two molybdaborane clusters. Electronic structure calcns. employing d. functional theory yield geometries in agreement with the structure detns., and on grounds of d. functional theory calcns., the authors analyzed the bonding patterns in the structure. [on SciFinder(R)]
    Inorganic Chemistry (Washington, DC, United States). 01/2010; 49:900-904.
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    ABSTRACT: Pyrolysis of (eta(5)-C(5)Me(5)WH(3))B(4)H(8), 1, in the presence of excess BHCl(2) x SMe(2) in toluene at 100 degrees C led to the isolation of (eta(5)-C(5)Me(5)W)(2)B(5)H(9), 2, and B-Cl inserted (eta(5)-C(5)Me(5)W)(2)B(5)H(8)Cl, 3, and (eta(5)-C(5)Me(5)W)(2)B(5)H(7)Cl(2), 4-7 (four isomers). All the chlorinated tungstaboranes were isolated as red and air and moisture sensitive solids. These new compounds have been characterized in solution by (1)H, (11)B, (13)C NMR, and the structural types were unequivocally established by crystallographic analysis of compounds 3, 4, and 7. Density functional theory (DFT) calculations were carried out on the model molecules of 3-7 to elucidate the actual electronic structures of these chlorinated species. On grounds of DFT calculations we demonstrated the role of transition metals, bridging hydrogens, and the effect of electrophilic substitution of hydrogens at B-H vertices of metallaborane structures.
    Inorganic Chemistry 07/2009; 48(14):6509-16. · 4.59 Impact Factor
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    ABSTRACT: Reaction of (η5-C5Me5)MoCl4 with a 10-fold excess of LiBH4 followed by thermolysis with excess BH3·THF in toluene led to the formation of two oxamolybdaborane clusters, (η5-C5Me5Mo)2B5(μ3-OEt)H6R (2, R = H; 3, R = n-BuO). Clusters 2 and 3 have been characterized by 1H, 11B, and 13C NMR spectra and X-ray crystal structure determinations. 2 and 3 are notable examples of oxametallaborane compounds where oxygen is contiguously bound to both the cluster metal (molybdenum) and the boron atom.
    03/2009;
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    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.
    Journal of Organometallic Chemistry 01/2009; 694(2):237–243. · 2.00 Impact Factor
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    ABSTRACT: Pyrolysis of (η5-C5Me5WH3)B4H8, 1, in the presence of excess BHCl2·SMe2 in toluene at 100° gave (η5-C5Me5W)2B5H9, 2, and B-Cl inserted (η5-C5Me5W)2B5H8Cl, 3, and (η5-C5Me5W)2B5H7Cl2, 4-7 (four isomers). All the chlorinated tungstaboranes were isolated as red and air and moisture sensitive solids. These new compds. were characterized in soln. by 1H, 11B, 13C NMR, and the structural types were unequivocally established by crystallog. anal. of compds. 3, 4, and 7. D. functional theory (DFT) calcns. were carried out on the model mols. of 3-7 to elucidate the actual electronic structures of these chlorinated species. On grounds of DFT calcns. the authors demonstrated the role of transition metals, bridging hydrogens, and the effect of electrophilic substitution of hydrogens at B-H vertexes of metallaborane structures. [on SciFinder(R)]
    Inorganic Chemistry (Washington, DC, United States). 01/2009; 48:6509-6516.
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    ABSTRACT: AbstractReaction of [(η5-C5Me5Mo)2B5H9], 1 with 5-fold excess of n-BuLi at −70°C followed by excess of RI (R=n-Bu or Ph) at room temperature yielded B-R inserted metallaboranes [(η5-C5Me5Mo)2B5H8R] (2: R=n-Bu, 5: R=Ph), [(η5-C5Me5Mo)2B5H7R2] (3, 4: R=n-Bu; 6, 7: R=Ph). Isolated yields of mono-alkyl/arylated species are better than di-alkyl/arylated ones. All the new cluster compounds have been characterized by IR, 1H, 11B, 13C NMR and mass spectroscopy as simple substitution derivatives of [(η5-C5Me5Mo)2B5H9] and the structural types of one of these species, 2 was established by X-ray crystallographic analysis. Graphical AbstractReaction of [(η5-C5Me5Mo)2B5H9], with 5-fold excess of n-BuLi at −70°C followed by excess of RI (R=n-Bu or Ph) at room temperature yielded B-R inserted metallaboranes [(η5-C5Me5Mo)2B5H9-nRn] (When R=n-Bu, n=2, 1; R=Ph, n=2, 1).
    Journal of Cluster Science 20(3):565-572. · 1.11 Impact Factor