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Fine‐Tuning of Metallaborane Geometries: Chemistry of Iridaboranes Derived from the Reaction of [(Cp*Ir) 2 H x Cl 4− x ] ( x =0‐2; Cp*= η 5 ‐C 5 Me 5 ) with LiBH 4
Author(s) -
Lei Xinjian,
Shang Maoyu,
Fehlner Thomas P.
Publication year - 2000
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/1521-3765(20000717)6:14<2653::aid-chem2653>3.0.co;2-h
Subject(s) - chemistry , computational chemistry
From reaction of [(Cp*Ir) 2 H x Cl 4− x ] ( x =1, 0) and LiBH 4 , arachno ‐[{Cp*IrH 2 }B 3 H 7 ]( 1 ) is produced in moderate yield concurrently with [Cp*IrH 4 ]. In contrast, reaction of [(Cp*Ir) 2 H 2 Cl 2 ] with LiBH 4 results in arachno ‐[{Cp*IrH} 2 ( μ ‐H)B 2 H 5 ] ( 3 ) in high yield at room temperature but a mixture of 1 and [{Cp*IrH} 2 ( μ ‐H)BH 4 ] ( 2 ) at 0 °C. BH 3 ⋅THF converts 1 to arachno ‐[{Cp*IrH}B 4 H 9 ] ( 4 ) and 2 to 3 with 1 as a minor product. Further, reaction of 3 with excess of BH 3 ⋅THF results in formation of nido ‐[{Cp*Ir} 2 ( μ ‐H)B 4 H 7 ] ( 6 ) formed by loss of H 2 from the intermediate arachno ‐[{Cp*IrH} 2 B 4 H 8 ] ( 5 ). Reaction of 1 with [Co 2 (CO) 8 ] permits the isolation of two metallaboranes, arachno ‐[{Cp*Ir(CO)}B 3 H 7 ] ( 7 ) and nido ‐[1‐{Cp*Ir}‐2, 3‐Co 2 (CO) 4 ( μ ‐CO)B 3 H 7 ] ( 8 ). Treatment of 4 with [Co 2 (CO) 8 ] gives only one single mixed‐metal metallaborane nido ‐[1‐{Cp*Ir}‐2‐Co(CO) 3 B 4 H 7 ( 9 ) in high yield. Finally, pyrolysis of 8 results in loss of hydrogen and formation of pileo ‐[1‐{Cp*Ir}‐2, 3‐Co 2 (CO) 5 B 3 H 5 ] ( 10 ) with a BH‐capped square‐pyramidal structure. With kinetic control rational synthesis of a variety metallaboranes has been achieved by varying the number of chlorides in the monocyclopentadienylmetal halide dimer, reaction temperature, types of monoborane, and metal fragment sources.