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Qian L, Ma KY, Zhou ZJ, Ma F. Design of a catalyst through Fe doping of the boron cage B 10H 14 for CO 2 hydrogenation and investigation of the catalytic character of iron hydride (Fe-H). Phys Chem Chem Phys 2017; 19:32723-32732. [PMID: 29199289 DOI: 10.1039/c7cp05953a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The innovative catalyst Fe@B10H14 is designed through Fe doping of the boron cage B10H14 and is employed to catalyze CO2 hydrogenation using a quantum mechanical method. First, the structure of the Fe@B10H14 complex is characterized through calculated 11B NMR chemical shifts and Raman spectra, and the interactions between Fe and the four H atoms of the opening in the cage are analyzed, which show that various iron hydride (Fe-H) characteristics exist. Subsequently, the potential of Fe@B10H14 as a catalyst for the hydrogenative reduction of CO2 in the gas phase is computationally evaluated. We find that an equivalent of Fe@B10H14 can consecutively reduce double CO2 to obtain the double product HCOOH through a two-step reduction, and Fe@B10H12 and Fe@B10H10 are successively obtained. The Fe presents single-atom character in the reduction of CO2, which is different from the common iron(ii) catalyzed CO2 reduction. The calculated total free energy barrier of the first CO2 reduction is only 8.79 kcal mol-1, and that of the second CO2 reduction is 25.71 kcal mol-1. Every reduction reaction undergoes two key transition states TSC-H and TSO-H. Moreover, the transition state of the C-H bond formation TSC-H is the rate-determining step, where the interaction between πC[double bond, length as m-dash]O* and the weak σFe-H bond plays an important role. Furthermore, the hydrogenations of Fe@B10H12 and Fe@B10H10 are investigated, which aim at determining the ability of Fe-H circulation in the Fe doped decaborane complex. We find that the hydrogenation of Fe@B10H10 undergoes a one-step H2-adsorbed transition state TSH-adsorb with an energy barrier of 6.42 kcal mol-1 from Fe@B10H12. Comparing with the hydrogenation of Fe@B10H10, it is slightly more difficult for the hydrogenation of Fe@B10H12, where the rate-determining step is the H2-cleaved transition state TS2H-H with an energy barrier of 17.38 kcal mol-1.
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Affiliation(s)
- Lei Qian
- School of Chemistry and Materials Science, Huaibei Normal University, Huaibei, 235000, China.
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2
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Synthesis and structural characterizations of ansa-vanadabis(tricarbadecaboranyl) sandwich complexes. J Organomet Chem 2015. [DOI: 10.1016/j.jorganchem.2015.04.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Berkeley ER, Perez-Gavilan A, Carroll PJ, Sneddon LG. Syntheses, Structural Characterizations, and Reactivity Studies of Half-Sandwich Cobalt, Rhodium, and Iridium Metallatricarbadecaboranyl Complexes. Organometallics 2015. [DOI: 10.1021/acs.organomet.5b00141] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Emily R. Berkeley
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
| | - Ariane Perez-Gavilan
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
| | - Patrick J. Carroll
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
| | - Larry G. Sneddon
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
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Ma F, Miao TF, Liu YT. Designing nonlinear optical molecule by incorporating the planar tetracoordinate unit NAl4- or CAl42- into decaborane B10H14. JOURNAL OF THEORETICAL & COMPUTATIONAL CHEMISTRY 2014. [DOI: 10.1142/s0219633614500424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Molecular Incorporation is an important approach of providing novel compounds with fascinating structures. In this paper, we theoretically described the incorporation of the central planar tetracoordinate molecules NAl 4- or CAl 42- into borane cluster B 10 H 14. By molecular orbital analysis, a novel four-fold Al – H bonding interaction was found, and it contributes to the molecular incorporation. In addition, we found that the counterion Li + is critical for the neutral incorporation species, due to its small atomic radii and little positive charge. To measure the nonlinear optical (NLO) response, the static first hyperpolarizabilities (β0) were evaluated at the second-order Møller–Plesset (MP2) level. The β0 values are 1708 a.u and 8682 a.u for [ B 10 H 14⋯ NAl 4]- and [ B 10 H 14⋯ CAl 4]2-, respectively, which indicates that the charge plays a significant role on deciding the value of β0. Moreover, it is different for the change of β0 value brought by counterion Li +. Li + decreases the β0 value of [ B 10 H 14⋯ CAl 4]2-, while it increases the β0 value of [ B 10 H 14⋯ NAl 4]-, therein, the sandwich-like B 10 H 14– Li – NAl 4( I ) exhibits considerable β0 value (31,253 a.u.). This reveals that it is possible to explore high-performance NLO materials based on suitable molecular incorporation. Besides, the present study is also expected to enrich the knowledge of the planar tetracoordinate carbon chemistry and boron chemistry.
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Affiliation(s)
- Fang Ma
- School of Chemistry and Materials Science, Huaibei Normal University, Huaibei 235000, P. R. China
| | - Ti-Fang Miao
- School of Chemistry and Materials Science, Huaibei Normal University, Huaibei 235000, P. R. China
| | - Ying-Tao Liu
- Department of Chemistry and Chemical Engineering, Ningxia University, Yinchuan 750012, P. R. China
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Gleeson B, Carroll PJ, Sneddon LG. Functionalized ferratricarbadecaboranyl complexes for potential anticancer applications. J Organomet Chem 2013. [DOI: 10.1016/j.jorganchem.2012.12.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Gleeson B, Carroll PJ, Sneddon LG. Syntheses and structural characterizations of inorganic ansa-metallocene analogues: ansa-ferratricarbadecaboranes. J Am Chem Soc 2013; 135:12407-13. [PMID: 23930745 DOI: 10.1021/ja405977q] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
New linked cyclopentadienyl-tricarbadecaboranyl and bis-tricarbadecaboranyl dianions have been used to form the first examples of ansa-metallatricarbadecaboranyl complexes. The hybrid cyclopentadienyl-tricarbadecaboranyl dianion, Li2(+)[6-C5H4-(CH2)2-nido-5,6,9-C3B7H9](2-) (1), was produced by an initial carbon-insertion reaction of a nitrile-substituted cyclopentadiene with the arachno-4,6-C2B7H12(-) anion, followed by deprotonation to the dianion with LiH. The linked-cage bis-tricarbadecaboranyl dianion, Li2(+)[6,6'-(CH2)2-nido-(5,6,9-C3B7H9)2](2-) (2), was produced by a similar carbon-insertion route involving the reaction of two equivalents of arachno-4,6-C2B7H12(-) with succinonitrile. The reaction of 1 with an equivalent of FeCl2 produced the hybrid complex, ansa-(2-(CH2)2)-(1-η(5)-C5H4-closo-1,2,3,4-C3B7H9)Fe (3), with a crystallographic determination confirming the formation of a sandwich structure where the ring and cage are linked by the ansa -CH2CH2- group with attachment to the cage at the C2 carbon. The reaction of 2 with FeCl2 produced three isomeric ansa-(CH2)2-ferrabistricarbadecaboranyl sandwich complexes, ansa-(CH2)2-(closo-C3B7H9)2Fe (4, 5 and 6). Crystallographic determinations showed that in 4, the two tricarbadecaboranyl ligands are linked by the ansa-CH2CH2- group at the C2 and C2' cage carbons, whereas in 5 and 6 they are linked at their C2 and C4' carbons, with the structures of 5 and 6 differing in the relative positions of the C4' carbons in the two cages of each complex. The structural determinations also showed that, depending upon the linking position of the ansa-tether, constraints in cage-orientation, such as observed in 4, produce unfavorable intercage steric interactions. However, the cage fragments in these complexes can readily undergo a cage-carbon migration that moves one -carbon and its tether linkage to the more favorable 4-position. This isomerization reduces the cage steric interactions and produces configurations, such as those found for 5 and 6, where the iron cage bonding is enhanced as a result of the binding effect of the tether.
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Affiliation(s)
- Brendan Gleeson
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, USA
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Voltammetry of half-sandwich manganese group complexes of η6-PhC3B7H9 and η5-C60Bn2PhH2, two ligands that are cyclopentadienyl mimicks. Inorganica Chim Acta 2010. [DOI: 10.1016/j.ica.2010.05.040] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Muhammad S, Xu H, Liao Y, Kan Y, Su Z. Quantum mechanical design and structure of the Li@B10H14 basket with a remarkably enhanced electro-optical response. J Am Chem Soc 2009; 131:11833-40. [PMID: 19642644 DOI: 10.1021/ja9032023] [Citation(s) in RCA: 222] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An innovative type of lithium decahydroborate (Li@B(10)H(14)) complex with a basketlike complexant of decaborane (B(10)H(14)) has been designed using quantum mechanical methods. As Li atom binds in a handle fashion to terminal electrophilic boron atoms of the decaborane basket, its NBO charge q (Li) is found to be 0.876, close to +1. This shows that the Li atom has been ionized to form a cation and an anion at the open end of B(10)H(14). The most fascinating feature of this Li doping is its loosely bound valence electron, which has been pulled into the cavity of the B(10)H(14) basket and become diffuse by the electron-deficient morphological features of the open end of the B(10)H(14) basket. Strikingly, the first hyperpolarizability (beta(0)) of Li@B(10)H(14) is about 340 times larger than that of B(10)H(14), computed to be 23,075 au (199 x 10(-30) esu) and 68 au, respectively. Besides this, the intercalation of the Li atom to the B(10)H(14) basket brings some distinctive changes in its Raman, (11)B NMR, and UV-vis spectra along with its other electronic properties that might be used by the experimentalists to identify this novel kind of Li@B(10)H(14) complex with a large electro-optical response. This study may evoke the possibility to explore a new thriving area, i.e., alkali metal-boranes for NLO application.
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Affiliation(s)
- Shabbir Muhammad
- Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun 130024, People's Republic of China
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Butterick R, Carroll PJ, Sneddon LG. General Method for the Selective Functionalization of Cyclopentadienyliron Tricarbadecaboranyl Complexes via Halogenation and Sonogashira Coupling Reactions. Organometallics 2008. [DOI: 10.1021/om8003898] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Robert Butterick
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323
| | - Patrick J. Carroll
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323
| | - Larry G. Sneddon
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323
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Nafady A, Butterick R, Calhorda MJ, Carroll PJ, Chong D, Geiger WE, Sneddon LG. Hyperelectronic Metal−Carborane Analogues of Cymantrene (MnCp(CO)3) Anions: Electronic and Structural Noninnocence of the Tricarbadecaboranyl Ligand. Organometallics 2007. [DOI: 10.1021/om700496v] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ayman Nafady
- Department of Chemistry, University of Vermont, Burlington Vermont 05405, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, and Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1749-016, Lisboa, Portugal
| | - Robert Butterick
- Department of Chemistry, University of Vermont, Burlington Vermont 05405, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, and Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1749-016, Lisboa, Portugal
| | - Maria José Calhorda
- Department of Chemistry, University of Vermont, Burlington Vermont 05405, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, and Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1749-016, Lisboa, Portugal
| | - Patrick J. Carroll
- Department of Chemistry, University of Vermont, Burlington Vermont 05405, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, and Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1749-016, Lisboa, Portugal
| | - Daesung Chong
- Department of Chemistry, University of Vermont, Burlington Vermont 05405, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, and Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1749-016, Lisboa, Portugal
| | - William E. Geiger
- Department of Chemistry, University of Vermont, Burlington Vermont 05405, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, and Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1749-016, Lisboa, Portugal
| | - Larry G. Sneddon
- Department of Chemistry, University of Vermont, Burlington Vermont 05405, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, and Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, 1749-016, Lisboa, Portugal
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Butterick R, Ramachandran BM, Carroll PJ, Sneddon LG. Chemistry of Mangana- and Rhenatricarbadecaboranyl Tricarbonyl Complexes: Evidence for an Associative Mechanism of Ligand Substitution Involving an η6−η4 Cage-Slippage Process Analagous to η5−η3-Cyclopentadienyl Ring-Slippage. J Am Chem Soc 2006; 128:8626-37. [PMID: 16802829 DOI: 10.1021/ja062201u] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The reaction of the tricarbadecaboranyl anion, 6-Ph-nido-5,6,9-C(3)B(7)H(9)(-), with M(CO)(5)Br [M = Mn, Re] or [(eta(6)-C(10)H(8))Mn(CO)(3)(+)]BF(4)(-) yielded the half-sandwich metallatricarbadecaboranyl analogues of (eta(5)-C(5)H(5))M(CO)(3) [M = Mn, Re]. For both 1,1,1-(CO)(3)-2-Ph-closo-1,2,3,4-MC(3)B(7)H(9) [M = Mn (2) and Re (3)], the metal is eta(6)-coordinated to the puckered six-membered open face of the tricarbadecaboranyl cage. Reactions of 2 and 3 with isocyanide at room temperature produced complexes 8-(CNBu(t))-8,8,8-(CO)(3)-9-Ph-nido-8,7,9,10-MC(3)B(7)H(9) [M = Mn (4), Re (5)], having the cage eta(4)-coordinated to the metal. Photolysis of 4 and 5 then resulted in the loss of CO and the formation of 1-(CNBu(t))-1,1-(CO)(2)-2-Ph-closo-1,2,3,4-MC(3)B(7)H(9) [M = Mn, Re (6)], where the cage is again eta(6)-coordinated to the metal. Reaction of 2 and 3 with 1 equiv of phosphine at room temperature produced the eta(6)-coordinated monosubstituted complexes 1,1-(CO)(2)-1-P(CH(3))(3)-2-Ph-closo-1,2,3,4-MC(3)B(7)H(9) [M = Mn (7), Re (9)] and 1,1-(CO)(2)-1-P(C(6)H(5))(3)-2-Ph-closo-1,2,3,4-MC(3)B(7)H(9) [M = Mn (8), Re (10)]. NMR studies of these reactions at -40 degrees C showed that substitution occurs by an associative mechanism involving the initial formation of intermediates having structures similar to those of the eta(4)-complexes 4 and 5. The observed eta(6)-eta(4) cage-slippage is analogous to the eta(5)-eta(3) ring-slippage that has been proposed to take place in related substitution reactions of cyclopentadienyl-metal complexes. Reaction of 9 with an additional equivalent of P(CH(3))(3) gave 8,8-(CO)(2)-8,8-(P(CH(3))(3))(2)-9-Ph-nido-8,7,9,10-ReC(3)B(7)H(9) (11), where the cage is eta(4)-coordinated to the metal. Photolysis of 11 resulted in the loss of CO and the formation of the disubstituted eta(6)-complex 1-CO-1,1-(P(CH(3))(3))(2)-2-Ph-closo-1,2,3,4-ReC(3)B(7)H(9) (12).
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Affiliation(s)
- Robert Butterick
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104-6323, USA
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Ramachandran BM, Wang Y, Kang SO, Carroll PJ, Sneddon LG. Syntheses and Structural Characterizations of Vanada- and Niobatricarbadecaboranyl Monohalide Complexes. Organometallics 2004. [DOI: 10.1021/om0498504] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Bhaskar M. Ramachandran
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, and Korea University, Seochang 208 Jochiwon, Choongnam, Korea 339-800
| | - Ying Wang
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, and Korea University, Seochang 208 Jochiwon, Choongnam, Korea 339-800
| | - Sang Ook Kang
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, and Korea University, Seochang 208 Jochiwon, Choongnam, Korea 339-800
| | - Patrick J. Carroll
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, and Korea University, Seochang 208 Jochiwon, Choongnam, Korea 339-800
| | - Larry G. Sneddon
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, and Korea University, Seochang 208 Jochiwon, Choongnam, Korea 339-800
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Ramachandran BM, Carroll PJ, Sneddon LG. Syntheses of Functionalized Ferratricarbadecaboranyl Complexes. Inorg Chem 2004; 43:3467-74. [PMID: 15154810 DOI: 10.1021/ic049827a] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The reactions of nitriles (RCN) with arachno-4,6-C(2)B(7)H(12)(-) provide a general route to functionalized tricarbadecaboranyl anions, 6-R-nido-5,6,9-C(3)B(7)H(9)(-), R = C(6)H(5) (2(-)), NC(CH(2))(4) (4(-)), (p-BrC(6)H(4))(Me(3)SiO)CH (6(-)), C(14)H(11) (8(-)), and H(3)BNMe(2)(CH(2))(2) (10(-)). Further reaction of these anions with (eta(5)-C(5)H(5))Fe(CO)(2)I yields the functionalized ferratricarbadecaboranyl complexes 1-(eta(5)-C(5)H(5))-2-C(6)H(5)-closo-1,2,3,4-FeC(3)B(7)H(9) (3), 1-(eta(5)-C(5)H(5))-2-NC(CH(2))(4)-closo-1,2,3,4-FeC(3)B(7)H(9) (5), 1-(eta(5)-C(5)H(5))-2-[(p-BrC(6)H(4))(Me(3)SiO)CH]-closo-1,2,3,4-FeC(3)B(7)H(9) (7), 1-(eta(5)-C(5)H(5))-2-C(14)H(11)-closo-1,2,3,4-FeC(3)B(7)H(9) (9), and 1-(eta(5)-C(5)H(5))-2-H(3)BNMe(2)(CH(2))(2)-closo-1,2,3,4-FeC(3)B(7)H(9) (11). Reaction of 11 with DABCO (triethylenediamine) resulted in removal of the BH(3) group coordinated to the nitrogen of the side chain, giving 1-(eta(5)-C(5)H(5))-2-NMe(2)(CH(2))(2)-closo-1,2,3,4-FeC(3)B(7)H(9) (12). Crystallographic studies of complexes 3, 5, 7, 9, and 11 confirmed that these complexes are ferrocene analogues in which a formal Fe(2+) ion is sandwiched between the cyclopentadienyl and tricarbadecaboranyl monoanionic ligands. The metals are eta(6)-coordinated to the puckered six-membered face of the tricarbadecaboranyl cage, with the exopolyhedral substituents bonded to the low-coordinate carbon adjacent to the iron.
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Hall IH, Durham RW, Tram M, Mueller S, Ramachandran BM, Sneddon LG. Cytotoxicity and mode of action of vanada- and niobatricarbadecaboranyl monohalide complexes in human HL-60 promyelocytic leukemia cells. J Inorg Biochem 2003; 93:125-31. [PMID: 12576274 DOI: 10.1016/s0162-0134(02)00565-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Vanada- and niobatricarbadecaboranyl monohalide complexes proved to be potent cytotoxic agents against murine and human leukemia and lymphoma growth as well as HeLa suspended uterine carcinoma. The vanada complex reduced the growth of KB nasopharynx, Hepe liver, HCT-8 ileum and 1-A9 ovary solid carcinomas. A mode of action study in human HL-60 promyelocytic leukemia cells showed that DNA and purine de novo syntheses were significantly inhibited with suppression of the regulatory enzymes activities of DNA polymerase alpha and PRPP-amido transferase. There was moderate inhibition of RNA synthesis and m-RNA polymerase activity. These complexes did not inhibit human topoisomerase I or II activity, although the niobium complex nicked the DNA. The complexes did activate caspases 3, 6 and 9 which are linked to apoptosis programmed cell death. These vanada- and niobatricarbadecaboranyl monohalide complexes appear to be more specific in their effects on leukemia cell metabolism than other sandwich complexes which have broad effects on multiple enzymes.
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Affiliation(s)
- Iris H Hall
- Division of Medicinal Chemistry and Natural Products, School of Pharmacy, University of North Carolina, Chapel Hill, NC 27599-7360, USA.
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Shedlow AM, Kadlecek DE, Clapper JC, Rathmill SE, Carroll PJ, Sneddon LG. Syntheses, crystallographic/computational characterizations, and reactions of the first 10-vertex arachno- and nido-phosphamonocarbaboranes. J Am Chem Soc 2003; 125:200-11. [PMID: 12515523 DOI: 10.1021/ja020944j] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A synthetic sequence involving the initial reaction of a substituted phosphorus dihalide (RPCl(2), R = CH(3), C(6)H(5)) with the arachno-CB(8)H(13)(-) (1-) monoanion followed by an in situ dehydrohalogenation reaction initiated by Proton Sponge, resulted in phosphorus cage insertion to yield the first 10-vertex arachno- and nido-phosphamonocarbaboranes, exo-6-R-arachno-6,7-PCB(8)H(12) (2a, 2b) and PSH(+)6-R-nido-6,9-PCB(8)H(9)(-) (PSH+3a-, PSH+3b-) (R = C(6)H(5) (a), CH(3) (b)). Alternatively, 2a and 2b were synthesized in high yield as the sole product of the reaction of the arachno-4-CB(8)H(12)(2-) (1(2-)) dianion with RPCl(2). Crystallographic determinations of PSH+3a- and PSH+3b- in conjunction with DFT/GIAO computational studies of the anions have confirmed the expected nido cage framework based on an octadecahedron missing the six-coordinate vertex. DFT/GIAO computational studies have also shown that while the gross cage geometries of the exo-6-R-arachno-6,7-PCB(8)H(12) compounds 2a and 2b resemble the known isoelectronic arachno-6,9-SCB(8)H(12), the phosphorus and carbon atoms are in thermodynamically unfavorable adjacent positions on the six-membered puckered face. They also each have an endo-hydrogen at the P6-position arising from proton transfer to the basic phosphorus during the cage-insertion reaction. Possible stepwise reaction pathways that can account for the formation of both the arachno and nido products are discussed. Deprotonation of 2a and 2b resulted in the formation of their corresponding conjugate monoanions, 6-R-arachno-6,7-PCB(8)H(11)(-) (2a-, 2b-), in which the proton that had been attached to the P6 atom was removed. Reactions of 2a- with O(2), S(8), BH(3).THF, or Br(2) further demonstrated the basicity of the P6-phosphorus yielding the new arachno-substituted compounds, endo-6-O-exo-6-(C(6)H(5))-arachno-6,7-PCB(8)H(11)(-) (4a-), endo-6-S-exo-6-(C(6)H(5))-arachno-6,7-PCB(8)H(11)(-) (5a-), endo-6-BH(3)-exo-6-(C(6)H(5))-arachno-6,7-PCB(8)H(11)(-) (6a-), and endo-6-Br-exo-6-(C(6)H(5))-arachno-6,7-PCB(8)H(11) (7a), respectively, in which the O, S, BH(3), and Br substituents are bound to the phosphorus at the endo position.
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Affiliation(s)
- Alexandra M Shedlow
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104-6323, USA
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Ramachandran BM, Trupia SM, Geiger WE, Carroll PJ, Sneddon LG. Synthetic, Structural, Chemical, and Electrochemical Studies of the Metallatricarbadecaboranyl Analogues of Ferrocene, Ruthenocene, and Osmocene and the Observation of a Reversible η6−η4 Tricarbadecaboranyl Coordination that Is Analogous to the η5−η3 Cyclopentadienyl Ring-Slippage Process. Organometallics 2002. [DOI: 10.1021/om020757u] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Bhaskar M. Ramachandran
- Departments of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, and University of Vermont, Burlington, Vermont 05405
| | - Sabrina M. Trupia
- Departments of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, and University of Vermont, Burlington, Vermont 05405
| | - William E. Geiger
- Departments of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, and University of Vermont, Burlington, Vermont 05405
| | - Patrick J. Carroll
- Departments of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, and University of Vermont, Burlington, Vermont 05405
| | - Larry G. Sneddon
- Departments of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, and University of Vermont, Burlington, Vermont 05405
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