Metallboranate und Boranatometallate. IX [1]; Äther‐Addukte von Tris(boranato)‐titan(III) und dimere Alkoxy‐bis(boranato)‐titan(III)‐Verbindungen

Abstract

Inhaltsübersicht. Die Umsetzung von TiCl4 mit LiBH4 in Äther liefert flüchtiges Ti(BH4)3 · O(C2H5)2, dessen Äther durch stärkere Basen (Tetrahydrofuran (THF), Dimethoxyäthan, o‐Dimethoxybenzol, Pyridin) verdrängt wird. Mit THF entsteht je nach Molverhältnis ein 1:1‐ oder ein 1:2‐Addukt. Pyridin gibt ein 1:2‐Addukt und entfernt außerdem BH3‐Gruppen aus Ti(BH4)3. Ti(BH4)3 · 2 THF erhält man am besten aus Ti(OiC3H7)4 und Diboran in THF. In Äther durchgeführt, bleibt die Reaktion auf der Stufe von Isopropyloxybis(boranato)titan(III) stehen. Nach demselben Verfahren wurden die Äthyloxy‐, butyloxy‐ und tert.‐butyloxy‐Verbindungen erhalten, die sich alle als dimer erwiesen. Versuche zur Darstellung von CH3OTi(BH4)2 werden beschrieben. Die NMR‐, IR‐ und UV‐Spektren der Verbindungen werden diskutiert. Metal Tetrahydroborates and Tetrahydroboratometallates. IX. Ether Adducts of Tris‐(tetrahydroborato)titanium(III) and Dimeric Alkoxy‐bis(tetrahydroborato)titanium(III) Compounds Abstract. The reaction of TiCl4 with LiBH4 in ether solution yields volatile Ti(BH4)3 · O(C2H5)2, the ether of which can be displaced by stronger bases (tetrahydrofurane (THF), dimethoxyethane, o‐dimethoxybenzene, pyridine). Depending on the molar ratio used 1:1‐ and 1:2 adducts of THF were formed. Pyridine yields a 1:2 adduct and removes BH3 groups from Ti(BH4)3. Ti(BH4)3 · 2 THF is best obtained from Ti(OiC3H7)4 and diborane in THF. This reaction carried out in ether solution, stops at the intermediate isopropyloxy‐bis(tetrahydroborato)titanium(III). The same procedure yields the ethyloxy‐, butyloxy‐ and the tert.‐butyloxy compound, all of them proved to be dimeric. Experiments for preparing CH3OTi(BH4)2 are described also. The n.m.r., i.r. and u.v. spectra of the compounds are discussed.

Transition metal tetrahydridoborates as models of methane activation: synthesis and structure of Ti(BH4)3(PMe3)2

“…1, 1986. 5), Ti-H(17) 1.73 (7), Ti-* -H(16) 2.25(7), Ti. -aH(15) 2.62 (7) Ti-B (2) 2.27( 1) , B (2)-H( 17) 0.95 (6), B (2)-H( 14) ,H ( 15) ,H ( 16) H (16).…”

“…aH(13) 2.40 (9). Torsion angles ("): Ti-H(13)-B(l)-H(ll), H (12) k 116(5), Ti-H( 17)-B(2)-H( 16) 28 (7), Ti-H( 17)-B(2)-H( 15) -94 ( 7), Ti-H( 17)-B (2)-H( 14) 15 1 (5).…”

“…H( 13) 1 .03 ( 7), B ( 1 )-H( 1 1 ) ,H ( 1 2) 1 . OO( 8) , H( 1 3)-B ( 1 )-H( 1 3 ' ) 0.96 (6), H(17)-B(2)-H( 16) 117( 6), H (17).…”

Metal Borohydrides beyond Groups I and II: A Review

“…The reaction in organic solvents (tetrahydrofuran or ether) between LiBH 4 and TiCl 4 ended in the formation of adducts such as Ti(BH 4 ) 3 ·2THF or Ti(BH 4 ) 3 ·2O(C 2 H 5 ) 2 [ 73 ]. In fact, several phosphines of titanium borohydrides (similarly produced to the latter compounds) are stable materials that can be used as a catalyst for polymerization and hydrogenation of olefins [ 21 , 74 ].…”

Solution-based routes to ammine metal borohydrides: formation of ammonia-borane

“…al., 24 and Nöth et al noted that dissolution of Ti(BH 4 ) 3 in pyridine afforded pyridine-borane. 25 However, this reaction pathway has not been recognised in recent work investigating AMBs as hydrogen storage media. 8 As can be seen in Figure 2a, the amount of AB formed with the s-and p-block metals correlates roughly with the Zhang electronegativity 19b with the exception of Zn, which shows the least tendency to produce the amine-borane adduct.…”