Organolanthanoids. XVII. The Synthesis of Bis(diphenylphosphinocyclopentadienyl)ytterbium(II) and Derived Heterobimetallic Complexes [Yb(thf)n(C5H4PPh2)2Z] [Z=Ni(CO)2, Mo(CO)4 or PtMe2; n = 1 or 2; thf = Tetrahydrofuran]. The X-Ray Crystal-Structure of [Yb(thf)2(C5H4PPh2)2Ni(CO)2]

Abstract

Reaction of diphenylphosphinocyclopentadiene with Yb (C6F5)2 or with ytterbium metal and Hg(C6F5)2 in tetrahydrofuran ( thf ) gives, after workup with toluene, the phosphinoytter-bocene , [Yb (C5H4PPh2)2( thf )]. Treatment with thf or with N,N,N′,N′- tetramethylethane-1,2-diamine ( tmen ) yields [ Yb (C5H4PPh2)2L2] (L = thf or L2 = tmen ). Redox trans- metallation between ytterbium metal and Tl (C5H4PPh2) in l,2-dimethoxyethane ( dme ) gives thallium metal and [ Yb (C5H4PPh2)2(dme )]. The ytterbium-transition metal hetero-bimetallics [ Yb ( thf ) (C2H4PPh2)2Z]. nPhMe [Z = Ni(CO)2, Mo(CO)4 or PtMe2, n = 2/3 or 1] have been prepared by reaction of [ Yb ( thf )(C5H4PPh2)2] with Ni(CO)2(PPh3)2, Mo(CO)4( nbd ) ( nbd = norbornadiene ) or PtMe2(cod) (cod = cycloocta-1,5-diene) in toluene. Treatment of the heterobimetallics with tetrahydrofuran [Z = PtMe2 or Mo(CO)4] or a preparation in thf /toluene [Z = Ni(CO)2] yields [ Yb ( thf )2(C5H4PPh2)2PtMe2]. thf, [ Yb ( thf )2(C2H4PPh2)2Mo(CO)4]. thf and [ Yb ( thf )2 (C5H4PPh2)2Ni(CO)2]. The X-ray crystal structure of the last compound (triclinic, space group Pi, a 14.514(5), b 13.565(1), c 10.866(5) 93.11(2), β 104.65(3), γ 97.25(2)�, U 2045 � 3 , Z 2, 5141 data refined to R 0.031) reveals eight-coordinate ytterbium with a pseudo-tetrahedral arrangement of two thf ligands and the cyclopentadienyl ring centroids of two ή5 -diphenylphosphinocyclopentadienide ligands . The latter are also bonded through phosphorus to the Ni(CO)2 group, resulting in tetrahedral stereochemistry for nickel. Infrared spectroscopy suggests the presence of ytterbium- isocarbonyl bonding in solid [ Yb ( thf )(C2H4PPh2)2Z] [Z = Ni(CO)2 or Mo(CO)4].

[Yb(THF)3(C5H4PPh2)2W(CO)4]·0.5THF and 1[Yb(THF)(C5H4PPh2)2(μ-OC)W(CO)3]: Two New Heterobimetallic Complexes Containing YbII and W0

“…A similar 31 P resonance was observed for 1 in [D 8 ]THF and in C 6 D 6 (sparing solubility at room temperature) consistent with the similar IR spectra for the compound in THF and toluene. As expected for a P−W coordination, a major shift of the 31 P resonance to higher frequencies (δ = 9− 10 ppm) than the value for [Yb(THF) 2 (CpPPh 2 ) 2 ] (δ = −20.5 ppm4) is observed, although this change is not as marked as that seen upon coordination of the Yb(CpPPh 2 ) 2 ligand to Ni(CO) 2 , PtMe 2 , or Mo(CO) 4 (δ = 17−20 ppm) 4. Further evidence for P−W bonding comes from observation of W−P coupling (see Exp.…”

“…The infrared spectra of the product in Nujol and in THF show four ν(CO) absorptions consistent with a cis ‐W(CO) 4 moiety, with values quite similar to those (2010, 1900, 1880, 1845 cm −1 )4 for the proposed complex [Yb(THF) 2 (CpPPh 2 ) 2 Mo(CO) 4 ]·THF in Nujol. Although the complex is almost insoluble in toluene (see below) the spectrum of the light green solution shows ν(CO) absorptions similar to the values for the complex in THF, suggesting dissolution of some of the complex as unchanged 1 .…”

“…Reaction of [Yb(THF)(CpPPh 2 ) 2 ]4 with W(CO) 6 in THF initially at room temperature and then at elevated temperatures yielded [Yb(THF) 3 (CpPPh 2 ) 2 W(CO) 4 ]· 0.5THF ( 1 ) [Equation (1 )]. Single crystals were also obtained from the same solvent, and readily underwent decomposition when taken out of the mother liquor precluding opportunity for microanalysis. …”

“…The introduction of the diphenylphosphanylcyclopentadienyl ligand (CpPPh 2 ) into organolanthanoid chemistry with Yb(CpPPh 2 ) 2 3 enabled the preparation of the first lanthanoid‐d‐block bimetallic complex with the f‐block element in the donor part of the molecule. Subsequently, other divalent4−7 and trivalent8−14 (diphenylphosphanylcyclopentadienyl)lanthanoid complexes have been prepared, including a Sm III complex with four different ligands,15 and a limited number of further bimetallics 4,9,12. Crystallographically characterized derivatives are relatively scarce (see also the related [Yb(THF) 2 (C 4 Me 4 P) 2 Ru(H) 2 (PPh 3 ) 2 ]16).…”

“…Crystallographically characterized derivatives are relatively scarce (see also the related [Yb(THF) 2 (C 4 Me 4 P) 2 Ru(H) 2 (PPh 3 ) 2 ]16). [Yb(THF) 2 (CpPPh 2 ) 2 Mo(CO) 4 ]·THF and [Yb(THF)(CpPPh 2 ) 2 Mo(CO) 4 ]·PhMe were prepared with carbonyls of Group 6 transition metals, and the latter was proposed to contain an iso ‐carbonyl−Yb linkage, although no crystal structures were determined 4. By preparing the tungsten carbonyl analogs, we have succeeded in crystallizing the key complexes [Yb(THF) 3 (CpPPh 2 ) 2 W(CO) 4 ]· 0.5THF ( 1 ) and [Yb(THF)(CpPPh 2 ) 2 (μ‐OC)W(CO) 3 ] ( 2 ) whose structures illuminate the nature of the Yb(CpPPh 2 ) 2 /Group 6 tetracarbonyl bimetallics.…”