Synthesis and Molecular Structure of the First Neutral Transition‐Metal Complex Containing a Linear MCCCCCR₂ chain

Abstract

Abstract:The reaction of [IrH,Cl(PiPr,),]

Closing the Gap between MC3 and MC5 Metallacumulenes: The Chemistry of the First Structurally Characterized Transition-Metal Complex with MdCdCdCdCR2 as the Molecular Unit

“…The bond length IrÀC1 is 1.816(6) ä and thus somewhat shorter than the Ir À C bond lengths in the related complexes trans-[IrCl( C C CPh 2 )(PiPr 3 ) 2 ] (1.862(7) ä) [13] and trans-[IrCl(CCCCCPh 2 )(PiPr 3 ) 2 ] (1.834(5) ä). [6] The lengths of the two internal carbon ± carbon double bonds are almost identical (1.283(8) and 1.275(8) ä), whereas the terminal bond C3ÀC4 is slightly longer (1.339(8) ä). The IrÀCl and IrÀP distances are very similar to those of the corresponding IrC 3 and IrC 5 complexes and thus consistent with the related binding properties of the : CCCPh 2 , : CCCCPh 2 and : CCCCCPh 2 units.…”

The First Structurally Characterized Metal Complex with the Molecular Unit M=C=C=C=CR2

“…The bond length IrÀC1 is 1.816(1) and thus somewhat shorter than the IrÀC bond lengths in trans-[IrF(CCCPh 2 )-(PiPr 3 ) 2 ] (1.853(19) ) [12] and trans-[IrCl( C C C C CPh 2 )-(PiPr 3 ) 2 ] (1.834 (5) ). [3] The lengths of the two internal CÀC double bonds are almost identical (1.283(8) and 1.275 (8) ), whereas the terminal bond C3ÀC4 is slightly longer (1.339 (8) ).…”

“…In 1994, Dixneuf and co-workers reported the synthesis of the first cationic complex with RuCCCCCPh 2 as the building block, [2] and a few months later we described the isolation of the first neutral compound with IrCCCCCPh 2 as the core unit. [3] In the meantime, the field of metallahexapentaenes [L x MC-( C) 4 RR'] has further been developed, mainly due to the work by Fischer et al [4] Earlier attempts to prepare metallapentatetraenes, that is compounds with n 3 in the above-mentioned formula, date back to Lomprey and Selegue [5] and somewhat later to Bruce and co-workers. [6] The latter group, by using [(h 5 -C 5 H 5 )Ru(PPh 3 ) 2 (thf)]PF 6 and buta-1,3-diyne as the starting materials, generated in situ a cationic complex containing the fragment Ru C C C CH 2 and supported the existence of this species by trapping reactions with nucleophiles such as NHPh 2 , PPh 3 , H 2 O, and imines.…”

Der Dihydridoiridium(III)-Komplex [IrH2Cl(PiPr3)2] als Molekülbaustein für unsymmetrische Rhodium-Iridiumund Iridium-Iridium-Zweikernverbindungen

“…Die Schmelzpunkte liegen mit 147°C (11) bzw. 166°C (12) ziemlich hoch, was in Anbetracht der zu vermutenden geringen Stabilita È t der Cycloocten-Metall-Bindungen erstaunlich ist. Von den NMR-spektroskopischen Daten ist die Resonanz der Ir±H-Protonen von 11 bei d = ±27.85 erwa È hnenswert, die nur eine 31 P-1 H-, jedoch keine 103 Rh-1 H-Kopplung zeigt und damit eine Bru È ckenposition der Hydridoliganden ausschlieût.…”