Decaborane Grignard Reagents

Unusual Closure of the Ten-Vertex Nido Cage via Alkylation: Regiospecific Synthesis of 3-Alkyl Derivatives of closo-1,2-C2B8H10

“…In view of the fact that that the alkylation of the [ nido -B 10 H 13 ] − anion takes place mostly at the apex B6 site, − it was reasoable to examine the comparable B-alkylation of the isoelectronic [ nido -5,6-R 1 2 C 2 B 8 H 9 ] − anions ( 2 – ). As illustrated in Scheme , reactions between the 2a – anion (Na + salt, generated in situ by treatment of the neutral nido -5,6-C 2 B 8 H 12 ( 2a ) carborane with excess NaH) and selected alkyl halides (RX) (where RX = MeI, EtBr, n -PrBr, i -PrBr, n -BuBr, and PhCH 2 Br) in boiling thetrahydrofuran (THF) result in the isolation of a series of B-substituted closo -1,2-C 2 B 8 H 9 -3-R ( 4a – 4f ) derivatives (see eq and Scheme ).…”

“…While the long-known alkylation of the [ nido -B 10 H 13 ] − anion takes place mostly at the apex B6 site, − a comparable B-alkylation of the isoelectronic [ nido -5,6-R 1 2 C 2 B 8 H 9 ] − anions ( 2 – ) with primary alkyl halides proceeds most likely at the equivalent apex B9-position, too. However, the anticipated 9-R substituted nido intermediates 3 tend to spontaneously loose dihydrogen, affording regioselectively 3-alkyl substituted closo- 1,2-dicarbadecaboranes 4 (for structural work in the area of type- 1 carboranes, see refs and ), even under relatively mild conditions employed in this work (refluxing THF).…”

Preparation and Properties of Sodium Decaboranate(12,2-)1

“…The only previous report of a Bi0Hi22species is that of the solvated Grignard reagent, Bj.0Hi2-(MgX)2-(C2H5)20, which was characterized by analysis. 5 Analytical results on sodium decaboranate(12,2-) and its molecular weight obtained by freezing-point depression in liquid ammonia support the formula Na2Bi0Hi2. Anal.…”

Natural convection boundary layers adjacent to pyrolyzing surfaces

“…The transient solutions were checked in several ways. For the case of pure thermal convection, transient temperature and velocity profiles were compared with HeUums [21] and the expected conduction-type solution for the early profiles [22]. Combined thermal and concentration buoyancy induced transient solutions were compared with those of Callahan and Marner [17].…”