Synthesen, spektroskopische Eigenschaften und Kristallstrukturen zweikerniger homo- und heteroleptischer μ-Carbido-Komplexe von Eisen(IV) mit Phthalocyaninat- und Tetraphenylporphyrinat-Liganden

Abstract

μ‐Carbidophthalocyaninato(2–)eisen(IV)tetraphenylporphyrinato(2–)eisen(IV) (2) wird neben μ‐Carbido‐bis(tetraphenylporphyrinato(2–)eisen(IV)) (1) durch die Reaktion von Phthalocyaninato(2–)ferrat(I) mit Dichlorcarbentetraphenylporphyrinato(2–)eisen(II) dargestellt. 1 und 2 lösen sich wie μ‐Carbido‐bis(phthalocyaninato(2–)eisen(IV)) (3) in Tetrahydrofuran, aber nur 2 und 3 bilden Solvens‐Addukte 2 a und 3 a, in denen thf trans‐ständig zum verbrückenden C‐Atom an jedes der Eisen‐Atome koordiniert. Aus thf kristallisieren die Solvate 1 · thf, 2 a · thf und 3 a · thf, deren Kristallstukturen bestimmt werden: 1 · thf, orthorhombisch, Fddd, a = 21,966(3) Å, b = 22,300(1) Å, c = 31,220(3) Å, Z = 8; 2 a · thf, orthorhombisch, P22121, a = 14,487(3) Å, b = 20,753(5) Å, c = 25,803(7) Å, Z = 4; 3 a · thf, orthorhombisch, P212121, a = 12,642(1) Å, b = 22,361(7) Å, c = 23,629(3) Å, Z = 4. In den drei Doppeldecker‐Komplexen sind beide „Tetrapyrrol”︁‐Liganden jeweils über eine lineare Fe–C–Fe‐Brücke in gestaffelter (1 · thf, 3 a · thf) oder ekliptischer Konformation (2 a · thf) gebunden. Der (Fe–C)‐Abstand schwankt zwischen 1,71 und 1,64 Å (Mittelwert: 1,68 Å). In 2 a · thf und 3 a · thf befinden sich die Eisen‐Atome fast im Zentrum (Ct) der (Np)4‐Ebenen (d(Fe–Ct) ∼ 0,1 Å), in 1 · thf sind sie dagegen um 0,27 Å in Richtung des Brücken‐C‐Atoms verschoben. Die makrozyklischen Liganden sind in 1 · thf sehr stark, sonst leicht gewellt. Die elektronischen Absorptionsspektren und Schwingungsspektren werden diskutiert.

Carbide complexes as π-acceptor ligands

“…However, counterexamples for carbide-containing homometallic, symmetric M-C-M bridges, e.g. M ¼ Nb, 44 Re, 45 Fe, [46][47][48][49][50] and Ru, 51 exist. The only previously reported system belonging to the present class, which has been structurally characterized, namely Grubbs' trans-[(Cy 3 P) 2 Cl 2 RuC-PdCl 2 (SMe 2 )], 16 provides a good basis for comparison with 5 as it contains RuC linearly coordinated to Pd(II).…”

Carbones and Carbon Atom as Ligands in Transition Metal Complexes

“…[Fe(TPP)] 2 C was obtained from Fe III (TPP)Cl in the presence of iron powder by reacting with CI 4 (TPP = 5, 10, 15, 20-tetraphenylporphyrin; according to Fe II the complex is diamagnetic [128]. The complex was also obtained upon reacting Fe(TPP) with Me 3 SiCCl 3 [129]; see also [130]. An X-ray analysis was performed in [131] and later in [130].…”

“…The complex was also obtained upon reacting Fe(TPP) with Me 3 SiCCl 3 [129]; see also [130]. An X-ray analysis was performed in [131] and later in [130]. The Mössbauer spectrum is published in [132].…”

“…[(thf)Fe(pc)] 2 C forms on dissolving [Fe(pc)] in THF. The asymmetric µ-carbido complex [(thf)(TPP)Fe=C=Fe(pc)(thf)] stems from the reaction of [FeCCl 2 (TPP)] with [Fe(pc)]-; both compounds were characterized by X-ray analyses [130].…”

Chromium carbides and cyclopropenylidenes

“…[27][28][29][30][31] In addition to those two types of dinuclear carbido complexes, dimetallacumulene structures of dinuclear -carbides have been reported generally with late-transition metals. [32][33][34][35][36][37][38] Recently, Hill and co-workers have reported a bent dimetallacumulene, which has rather a dimetallocarbene character, called dirhoda-heterocyclic carbene. 39 The dimetallocarbene species 39,40 can bind various Lewis acids to form trinuclear  3 -carbides, which have been investigated by Takemoto and Matsuzaka.…”