Wolfgang Petz

Carbodiphosphoranes and Related Ligands

The theoretical and experimental research on carbodiphosphoranes C(PR3)2 and related compounds CL2, both as free molecules and as ligands in transition metal complexes, is reviewed. Carbodiphosphoranes are examples of divalent carbon(0) compounds CL2 which have peculiar donor properties that are due to the fact that the central carbon atom has two lone electron pairs. The bonding situation is best described in terms of L→C←L donor acceptor interactions which distinguishes CL2 compounds (carbones) from divalent carbon(II) compounds (carbenes) through the number of lone electron pairs. The structures and stabilities of transition metal complexes with ligands CL2 can be understood and predictions can be made considering the double donor ability of the carbone compounds.

Carbamoylkomplexe aus C(NMe2)4 und übergangsmetallcarbonylen

Abstract C(NMe 2 ) 4 reacts with Fe(CO) 5 and Ni(CO) 4 to form carbamoyl complexes of the general formula [M(CO) x CONMe 2 ] − [C(NMe 2 )3] + (M = Fe, Ni; x = 4, 3). The structure of the salt-like compounds is deduced from IR and NMR spectroscopic data.

Mono- und dicarbenkomplexe durch reaktion von pentacarbonyleisen mit einigen dialkylamiden des zwei- und vierwertigen zinns

Abstract The dialkylamides of tin react with ironpentacarbonyl to form carbene complexes. With Me 2 Sn(NMe 2 ) 2 and Sn(NMe 2 ) 4 yellow dicarbene complexes are formed by addition of two SnN bonds to adjacent carbonyl groups. The two carbenoid systems on the central atom are parts of a chelate ligand connected by an OSnO bridge. Using [Sn(NMe 2 ) 2 ] 2 , a red monomeric compound (CO) 3 Fe(CONMe 2 ) 2 Sn containing the same cyclic structural unit can be isolated. The free activation enthalpy of rotation about the C(carbene)N bond in the tin (IV) dicarbene complexes was found to be 16.5 kcal mol -1 .

Carbonyl insertion into zirconium–nitrogen bonds; synthesis and X-ray structure of a carbene complex composed of [Zr(NMe2)4]2 and three Fe(CO)5 units containing Fe→Zr donor–acceptor interactions

Abstract The reaction of [Zr(NMe 2 ) 4 ] 2 with Fe(CO) 5 leads to the multicarbene complex ( 1 ) containing two zirconium and three iron atoms. The crystal structure revealed that 1 results from the insertion of five CO groups into ZrN bonds generating chelating biscarbene ligands at two iron atoms and one terminal carbene ligand at the third iron atom. Thus, a planar and a boat-configured ring are formed ( A and B ) with relatively short FeZr distances of 284 and 282 pm, respectively, indicating early–late transition-metal interactions.

Neuartige Dicarbenstannylen-Komplexe und Stickstoff-Zinn-Ylid-Komplexe durch verwendung von [Sn(NMe2)2]2 als komplexligand

Abstract The reaction of [Sn(NMe 2 ) 2 ] 2 with photochemically generated M(CO) 5 · THF complexes yields the dimeric nitrogen-tin ylide complexes [(CO) 5 MSn(NMe 2 ) 2 ] 2 (M = Cr, Mo, W). With pentacarbonyliron by addition of the two SnN bonds to neighbouring carbonyl groups dicarbene-stannylene complexes are formed. The structures of these compounds are deduced from IR and 1 H NMR spectra.

Darstellung, Kristallstruktur und quantenchemische Berechnung von [C(NMe2)3]2[(CO)4FeInCl3]

Die Titelverbindung (1) wurde in Form farbloser Kristalle bei der Umsetzung von InCl3 mit [C(NMe2)3][(CO)4FeC(O)NMe2] in THF erhalten. Die Kristallstruktur (monoklin, C2/c) zeigt das Vorliegen getrennter Ionen mit einem fehlgeordneten und einem nicht fehlgeordneten Kation. Im Dianion bilden die CO-Gruppen des trigonal-bipyramidal koordinierten Eisenatoms und die Chloratome des tetraedrisch koordinierten Indiumatoms eine gestaffelte Konformation mit einer relativ kurzen Fe–In-Bindungslange von 252 pm. Quantenchemische DFT-Rechnungen von [CO)4FeInCl3]2– zeigen, dass die Fe–In-Bindung einen stark ionischen Charakter aufweist und dass das Anion als ein Addukt von [Fe(CO)4]2– an InCl3 aufgefasst werden sollte. Preparation, Structure, and Quantum Chemical Calculation of [C(NMe2)3]2[(CO)4FeInCl3] The title compound (1) has been obtained as colorless crystals by reacting InCl3 with [C(NMe2)3][(CO)4FeC(O)NMe2] in THF solution. The crystal structure determination (monoclinic, C2/c) shows the presence of separate ions with one disordered and one non disordered cation. In the dianion the CO groups of the trigonal bipyramidal coordinated iron atom and the Cl atoms of the tetrahedral coordinated indium atom form a staggered conformation with a relatively short In–Fe bond distance of 252 pm. Quantum Chemical DFT calculations of [CO)4FeInCl3]2– show that the Fe–In bond has a strong ionic character and that it should be considered as an adduct of [Fe(CO)4]2– and InCl3.

On the reaction of Fe(CO)5 with Ti(NMe2)4: Synthesis of (CO)4FeC(NMe2)OTi(NMe2){OC(NMe2)}2, Fe(CO)3

Ti(NMe2)4 reacts with Fe(CO)5 in pentane or toluene by insertion of coordinated CO groups into TiN bonds. Whereas with a 1:1 mole ratio of the reactants 1 is formed quantitatively, use of longer reaction times and an excess of Fe(CO)5 gives the metallocyclic carbene complex 2. The compounds have been chartcterized by 1H, 13C NMR, IR, and Mossbauer spectroscopy.

Thiocarbonylkomplexe des eisens : II. Darstellung und eigenschaften von[(CO)4FeC(S)NMe2]− und (CO)4FeC(SMe)NMe2☆

Abstract (CO) 4 FeCS reacts with the ortho amide of the carbon acid C(NMe 2 ) 4 to yield the anionic thiocarbamoyl complex I, which with “magic methyl” can be converted into the neutral carbene complex. The spectroscopic properties (IR, NMR and mass spectra) of the new complexes are discussed.

Thiocarbonyl complexes of iron: IV. Concerning the reaction of (CO)4FeCS with mercury chloride in various solvents☆

Abstract Mercury chloride, suspended in n-pentane, reacts with the iron carbonyl complexes (CO) 4 FeCS and Fe(CO) 5 at room temperature to yield adducts of the composition (CO) 4 FeCS · 3HgCl 2 ( 1a ) and (CO) 5 Fe · 3HgCl 2 ( 1b ), respectively. The IR spectra reveal that both carbonyl compounds contain an iron—mercury donor bond. In ethanol as the solvent, the thiocarbonyl complex incorporates a solvent molecule, to yield the bright yellow thioalkoxycarbonyl complex cis -(CO) 4 Fe(HgCl)(C(S)OC 2 H 5 ) ( 2 ), whereas Fe(CO) 5 undergoes an oxidative addition to form the well known cis -(CO) 4 Fe(HgCl) 2 ( 4 ) under the same reaction conditions. The mass spectrum of 2 exhibits the molecular ion as well as that of a dimer with the composition Fe 2 (CO) 5 [C(S)OC 2 H 5 ] 2 ( 6 ), which is probably formed during the process by the thermal decomposition of 12 . Attempts to isolate 6 by pyrolysis of 2 gave a red-brown oil which could not be purified. From Mossbauer spectroscopic studies a carbenoid formula for 2 can be excluded. In aqueous solution the reaction of (CO) 4 FeCS with mercury chloride results in the formation of the yellow insoluble HgFe(CO) 3 CS ( 3 ). A polymer structure similar to that of HgFe(CO) 4 is proposed for 3 .

Thiocarbonyl complexes of iron V. New thiocarbonyl complexes derived by substitution from Fe(CO)4CS

Abstract Reaction of Fe(CO) 4 CS ( 1 ) with PR 3 (PR 3 = PPh 3 , PPh 2 Me) in the presence of ONMe 3 gives the substituted derivatives Fe(CO) 3 (CS)PR 3 ( 2 ) and Fe(CO) 2 (CS)(PR 3 ) 2 ( 3 ) in moderate yields. The compounds have been characterized by inrared, 13 C, and 31 P NMR spectroscopy. At least two isomers of 2 were identified by IR spectroscopy, the CS ligand is probably in the equatorial position of the trigonal-bipyramidal environment of the iron atom in one of these isomers and in the axial position in the other.