Preparation and properties of 6-ethoxy-, 6-phenyl-, and 6-trimethylsiloxydecaborane(14)

Loffredo, Robert E.; Drullinger, Linda F.; Slater, Jane A.; Turner, Charles A.; Norman, A. D.

doi:10.1021/ic50156a052

Cited by 16 publications

(19 citation statements)

References 26 publications

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“…Instead, triplets at 3.97 and 2.73 ppm and multiplets at 1.82 and 1.71 ppm were present, suggesting the presence of a linear alkyl ether motif rather than an intact ethereal ring (Figure S20). This observation was further supported by 13 C and 143.20, 133.78, 128.25, 128.23, 22.8 ppm) and alkyl ether (70.33, 35.21, 30.49, and 36.56 ppm). In total, these data led us to conclude that the compound consisted of a B7-O bound, ring-opened THF molecule that resides between the electrophilic boron cluster and nucleophilic substrate (5).…”

Section: Resultssupporting

confidence: 57%

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Metal-Catalyzed and Metal-Free Nucleophilic Substitution of 7-I-B18H21

Anderson

Djurovich

Rubio

et al. 2022

Preprint

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In this work, two pathways of reactivity are investigated to generate site-specific substitutions at the B7 vertex of the luminescent boron cluster, anti-B18H22. First, a palladium-catalyzed cross-coupling reaction utilizing the precursor 7-I-B18H21 and a series of model nucleophiles was developed, ultimately producing several B-N and B-O substituted species. Interestingly, the B-I bond in this cluster can also be substituted in an uncatalyzed fashion, leading to the formation of various B-N, B-O, and B-S products. This work highlights intricate differences corresponding to these two reaction pathways and analyzes the role of solvents and additives on the product distributions. As a result of our synthetic studies, seven new B18-based clusters were synthesized, isolated, and characterized by mass spectrometry and Nuclear Magnetic Resonance (NMR) spectroscopy. The photoluminescent properties of two structurally similar ether and thioether products were further investigated, with both exhibiting blue fluorescence in solution at 298 K and long-lived green or yellow phosphorescence at 77 K. Overall, this work shows for the first time the ability to perform substitution of a boron-halogen bond with nucleophiles in a B18-based cluster, resulting in the formation of photoluminescent molecules.

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Section: Resultssupporting

confidence: 57%

“…Structural formulations of these products were confirmed by ESI(-)MS and 1 H{ 11 B}, 11 B{ 1 H}, 11 B, 13 C, 19 F, HMQC NMR spectroscopy. Interestingly, neither the reactions in THF nor toluene led to significant formation of 4, potentially due to its weak nucleophilicity.…”

Section: Resultsmentioning

confidence: 82%

Metal-Catalyzed and Metal-Free Nucleophilic Substitution of 7-I-B18H21

Anderson

Djurovich

Rubio

et al. 2022

Preprint

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“…These have been obtained from the oxidation reactions of sodium decaborate ([Na þ ][B 10 H 13 À ]) using either I 2 in organic ethers, which gave low yields (<26%) of B 10 H 13 OR products of unconfirmed regiochemistry, 7 or stannic chloride in diethyl ether, which produced a mix of 5-and 6-C 2 H 5 O-B 10 H 13 (15:85; 5OR:6OR) in unreported yields. 8 In contrast, the reactions presented in the following sections have now been shown to provide general General Reaction Methods. Reactions were carried out in sealable 100 mL flasks, equipped with a stir bar, side arm, and Teflon stopcock (without a rubber O-ring), and were stirred after being sealed under N 2 at atmospheric pressure.…”

Section: ' Introductionmentioning

confidence: 99%

Syntheses and Surprising Regioselectivity of 5- and 6-Substituted Decaboranyl Ethers via the Nucleophilic Attack of Alcohols on 6- and 5-Halodecaboranes

2011

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The selective syntheses of new classes of decaboranyl ethers containing a range of functional groups substituted at the B5 or B6 positions were achieved through the reaction of alcohols with halodecaboranes. The surprising regioselectivity of the reaction, where the reaction of the 6-halodecaboranes (6-X-B(10)H(13)) with alcohols yielded the 5-substituted decaboranyl ethers (5-RO-B(10)H(13)) and the reaction with 5-halodecaboranes (5-X-B(10)H(13)) gave the 6-substituted decaboranyl ethers (6-RO-B(10)H(13)), was confirmed by NMR and X-ray crystallographic analyses. The crystallographic determinations also showed that the decaboranyl ethers had shortened B-O bonds and apparent sp(2) hybridization at oxygen indicating significant π-backbonding from oxygen to the cage boron. A possible substitution mechanism was computationally identified involving: (1) initial nucleophilic attack by the alcohol-oxygen at a site adjacent to the 5- or 6-halo-substituted boron, (2) movement of the terminal hydrogen at the point of attack to a bridging position, (3) formation of a 5-membered (B-O-H-Cl-B) cyclic transition state allowing the acidic methanolic-hydrogen to bond to the halogen, (4) release of HX, and finally (5) movement of a bridging hydrogen into the vacated terminal position. Deuterium labeling studies confirmed the movement of hydrogen from a bridging position of the halodecaborane into the halogen-vacated terminal position on the decaboranyl ether product. The relative reaction rates of the 6-X-B(10)H(13) compounds (X = F, Cl, Br, I) with alcohols were likewise found to be consistent with this mechanism.

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“…Removal of one vertex from a 12-vertex closo -heteroborane cluster also leads to 11-vertex nido -heteroboranes and -borates [ 2 , 4 , 5 ]. Experimentally known 11-vertex nido -heteroborane and -borate clusters include: group 14 heteroatoms, i.e., carbon [ 6 – 9 ], silicon [ 10 – 13 ], germanium [ 14 – 17 ] and tin [ 6 – 8 , 18 – 21 ]; group 15 heteroatoms, i.e., nitrogen, phosphorus [ 1 , 2 ], arsenic [ 5 , 22 – 32 ] and antimony [ 33 ]; group 16 heteroatoms, i.e., sulfur [ 34 ], selenium [ 35 – 41 ] and tellurium [ 35 – 37 , 42 , 53 ]. Williams’ qualitative rules predict isomers with low-coordinate heteroatoms and separated heteroatoms to be preferred [ 6 , 54 , 55 ].…”

Section: Introductionmentioning

confidence: 99%

Periodic trends and easy estimation of relative stabilities in 11-vertex nido-p-block-heteroboranes and -borates

Kiani

Hofmann

2005

J Mol Model

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Density functional theory computations were carried out for 11-vertex nido-p-block-hetero(carba)boranes and -borates containing silicon, germanium, tin, arsenic, antimony, sulfur, selenium and tellurium heteroatoms. A set of quantitative values called ''estimated energy penalties'' was derived by comparing the energies of two reference structures that differ with respect to one structural feature only. These energy penalties behave additively, i.e., they allow us to reproduce the DFT-computed relative stabilities of 11-vertex nidoheteroboranes in general with good accuracy and to predict the thermodynamic stabilities of unknown structures easily. Energy penalties for neighboring heteroatoms (HetHet and HetHet¢) decrease down the group and increase along the period (indirectly proportional to covalent radii). Energy penalties for a fiverather than four-coordinate heteroatom, [Het 5k (1) and Het 5k (2)], generally, increase down group 14 but decrease down group 16, while there are mixed trends for group 15 heteroatoms. The sum of HetHet¢ energy penalties results in different but easily predictable openface heteroatom positions in the thermodynamically most stable mixed heterocarbaboranes and -borates with more than two heteroatoms.

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Preparation and properties of 6-ethoxy-, 6-phenyl-, and 6-trimethylsiloxydecaborane(14)

Cited by 16 publications

References 26 publications

Metal-Catalyzed and Metal-Free Nucleophilic Substitution of 7-I-B18H21

Metal-Catalyzed and Metal-Free Nucleophilic Substitution of 7-I-B18H21

Syntheses and Surprising Regioselectivity of 5- and 6-Substituted Decaboranyl Ethers via the Nucleophilic Attack of Alcohols on 6- and 5-Halodecaboranes

Periodic trends and easy estimation of relative stabilities in 11-vertex nido-p-block-heteroboranes and -borates

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