A series of heterocyclic metal carbene complexes were prepared by the deoxygenation reaction of M(CO) 6 (M ) Cr, Mo, W) with RNH(CH 2 ) n NdPPh 3 (R ) H, Et, Ph; n ) 2, 3, 4) to form the corresponding isocyanide complex, which subsequently underwent intramolecular cyclization to give (CO) 5 MdCN(R)(CH 2 ) n NH in good yields. None of the carbene complex reacted further with amine-phosphinimine RNH(CH 2 ) n NdPPh 3 to give the bis(carbene) complex. Deprotonation of the N-H of the carbene complex followed by the reaction of alkyl iodides provided the N-alkylated product. In the case of N-allyl-substituted complexes (CO) 5 MdCNR(CH 2 ) 2 N(CH 2 CHdCH 2 ) (M ) Cr, Mo, W), the carbon-carbon double bond underwent intramolecular ligand displacement of carbonyl ligand to yield the corresponding π-coordinated complex. Unlike the group VI metal carbonyl complexes, treatment of ReBr(CO) 5 with 2 molar equiv of Ph 3 PdN(CH 2 ) 2 NH 2 provided a bis(carbene) complex fac-(CO) 3 BrRe(dCNHCH 2 CH 2 NH) 2 . All complexes are characterized by both spectral and elemental analyses. Complexes (CO) 5 ModCNHCH 2 CH 2 CH 2 NH (18) and fac-(CO) 3 BrRe-(dCNHCH 2 CH 2 NH) 2 (42) were further characterized by X-ray single-crystal analysis.
The incorporation of a phosphinimino moiety into phosphine ligands to form a new bidentate Ph3P=N(CH&PPh2 (1) is reported. Compound 1 can act as a a-N and a-P donor ligand or react with metal carbonyls to form isocyanide complexes. Complexes of (COkM-(1-PJV) [M = Mo (2), W (3)l were prepared from the reaction of Et4N[M(C0)5Brl with 1 in refluxing THF solution, whereas the isocyanide complexes of (C0)5MCN(CH2)3PPh2 [M = Cr (4), Mo (5), W (6)] are obtained from the reaction of M(CO)6 with 1 at 25 "C. The deoxygenation nature is also shown in the reaction of CpFe(C0)21, CpRu(C0)21, Re(CO)sBr, and R e ~( C 0 ) ~o with 1 to form the corresponding isocyanide complexes [CpFe(CO){ CN(CHd3-PPhz-CQ}]I (71, C~RU(CO)I{CN(CHZ)~PP~Z-C) (lo), BrRe(CO),-,{ CN(CH2)3PPhz-C}, [n = 1 (12), 2 (14)], and R ~~( C O ) S { C N ( C H ~) ~P P ~~-C }(15), respectively. The free phosphine of 10 underwent exchange with one triphenylphosphine ligand in CpRu(PPh3)sCl to yield the binuclear species [CpRu(PPhs)Cl{ P(Ph2)(CH2)3NC}Ru(CO)CpI](l l), whereas intramolecular ligand substitution occurred in both 12 and 15 to give Br(CO)3Re{CN(CH2)3PPhz-C9) (13) and {pCN(CH2)3PPhz)Rez(CO)8 (16). Reaction of (COD)PdC12 with 1 produced the complex (1-PJV)PdC12 (18), in which 1 acts as a a-N, a-P bidentate ligand. X-ray crystal structural analysis of [CpFe(CO){ CN(CH2)3PPh2-C,P}]PF6 (7a) and 18 confirmed the formulation of both complexes. The C z N bond distance [1.20(3) A] of 7a is greater than those in the related iron-isocyanide complexes; the angle C-N-C [ 141( 2)"] deviates from MOO, indicating that the resonance contribution of Fe=C=N-is more important than that of Fe-CEN-. These observations are consistent with spectral data, the smaller infrared stretching wavenumber (2089 cm-l), and the greater shift (13C NMR 6 183.7 ppm) of the isocyanide moiety of 7.
Only alkyne and carbene ligands surround the tungsten atom in complexes 1 and 2. Complex 1, which has been characterized by X‐ray crystallography, catalyzes the polymerization of diphenylacetylene (see below). L PhC CPh.
tive Bindung fiihren wir deshalb auf die kurzen Li-N-Abstande im Festkorper zuruck, die offensichtlich auch in Losung erhalten bleiben. Bemerkenswerterweise korrelieren die Betrage der Kopplungen mit den Li-N-Abstanden, und die aus der Rontgenstrukturanalyse erhaltenen Abstande liegen in einem Bereich, der eher fur Li-N-Bindungen in Lithi~mamiden['~] als fur koordinative Bindungen von Aminliganden (212 -230 pm [151) typisch ist. Eine Korrelation zwischen dem Abstand der koppelnden Kerne und dem Betrag der skalaren Wechselwirkung wurde auch bei einer 15N,'07,'09Ag-Koppl~ng in zweizahnigen Silber(1)-Komplexen mit Amin/Imin-Liganden f e s t g e ~t e l l t . [ ~~, ~~I Als mogliche Erklarung fur diese ungewohnliche Spin-Spin-Wechselwirkung bietet sich der Through-space-Mechanismus an, der fur lYF,l9Fund 'H,'H-Wechselwirkungen bei sterischer Kompression gut bekannt ist.['*] Dynamische Prozesse konnten dafur verantwortlich sein, dal3 bei TMEDA-Liganden bisher keine 6Li,15N-Kopplung festgestellt wurde.[20]
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