2‐Halogeno‐1,3,2‐diselenaphospholanes with an Annelated Dicarba‐closo‐dodecaborane(12) Unit: Synthesis, Molecular Structure and Reactivity

Abstract

Exchange reactions of 2,2‐dimethyl‐4,5‐[1,2‐dicarba‐closo‐dodecaborano(12)]‐1,3‐diselena‐2‐silacyclopentane with phosphorus trihalides PX3 (X = Cl, Br, I) led to the corresponding phospholanes in high yield. The solid‐state structure of the iodide was determined by X‐ray crystallography. Treatment of the bromide with nBu3SnH afforded the parent phosphane. The reaction of the iodide with LiAlH4 in [D8]toluene proceeded very slowly and mainly gave the deuterated phosphane. All products were characterised in solution by multinuclear magnetic resonance methods (1H, 13C, 31P and 77Se NMR). Molecular gas‐phase geometries were optimised at the B3LYP/6‐311+G(d,p) level of theory, and NMR parameters were calculated.

Novel 1,3-dichalcogeno-2-phospholanes with an annelated 1,2-dicarba-closo-dodecaborane(12) Unit

“…The best synthetic strategy starts from the silanes 6 (Scheme 4) (Wrackmeyer, 2012;Wrackmeyer, , 1929Wrackmeyer, -1948, although the di-lithium salts 3 (E = S, Se) can also be used (Wrackmeyer, 2007;Wrackmeyer, 2014, Dalton Trans.). However, the reactions of the silanes 6 with phosphorus halides afford the products in higher purity and much better yield.…”

“…The phosphorus halides 11 are more stable than their oxygen analogues 7, since the disproportionation products analogous to 8 play a minor role for X = Cl and even less so for X = Br, I. Therefore, the halides can be used to generate the parent compound 13 (R = H) as well as the fluoride 14 (X = F, for E = S) (Scheme 5), at least in reaction solutions in order to measure the most relevant NMR data (Wrackmeyer, 2012;Wrackmeyer, 2014, Dalton Trans.). Figure 3 shows the results of some NMR spectroscopic measurements for 13 (E = S) as an instructive example (Wrackmeyer, 2014, Dalton Trans.).…”

“…Figure 3 shows the results of some NMR spectroscopic measurements for 13 (E = S) as an instructive example (Wrackmeyer, 2014, Dalton Trans.). The NMR data for the corresponding 13 (E = Se) contain even more information, since the 77 Se NMR parameters are also accessible (Wrackmeyer, 2012). Of particular interest is the spin-spin coupling between 1 H(B-3) and 1 H(P) (Fig.…”

Boron, aluminium, gallium, indium and thallium

“…91 The XE{1,2-Se 2 C 2 B 10 H 10 } (E = B or P, X = halide) clusters were synthesised and demonstrated to undergo alkyne insertion into the B-Se bonds of the borolane moiety. 92,93 Metallaboranes, metallaheteroboranes and exo-metallaheteroboranes A number of new transition metal centred boron molecular wheels have been observed, including [MrB 9 ] À (M = Rh or Ir, compounds VII and VIII) and [M 0 rB 10 ] À (M 0 = Nb or Ta), the first deca-coordinated 2D structures. 94 Photoelectron spectroscopy suggested that the former have stable neutral forms, MrB 9 .…”

Reactions of 1,3,2‐Diselenaphospholanes with Lewis Acids: Borane and (Pentamethylcyclopentadienyl)rhodium and ‐iridium Dichloride

“…Our interest in such compounds with an annelated 1,2‐dicarba‐ closo ‐dodecaborane(12) unit prompted us to explore the behavior of 1,3,2‐diselenaphospholanes 1 7 and 2 6,7 towards Lewis acids such as BH 3 (as adduct with THF or SMe 2 ), Br 2 BH–SMe 2 , and [Cp*MCl 2 ] 2 (M = Rh, Ir). Phospholanes 1 and 2 were selected because 1 stays mainly as a monomer in solution and 2 does not show any tendency at all for dimerization, and both 1 and 2 possess analogous solution‐state structures as far as the five‐membered rings are concerned 7,8. Furthermore, selenium may compete with phosphorus for the Lewis acid, in particular if the basicity of phosphorus is reduced.…”