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31P-NMR and X-ray studies of new rhodium(I) β-ketoiminato complexes Rh(R1C(O)CHC(NH)R2)(CO)(PZ3) where PZ3=PPh3, PCy3, P(OPh)3 or P(NC4H4)3.

Autorzy

Y. S. Varshavsky

M. R. Galding

T. G. Cherkasova

I. S. Podkorytov

A. B. Nikol’skii

Anna M. Trzeciak

Zofia Olejnik

Tadeusz Lis

Józef J. Ziółkowski

Rok wydania

2001

Czasopismo

Journal of Organometallic Chemistry

Numer woluminu

628

Strony

195-210

DOI

10.1016/S0022-328X(01)00805-1

Kolekcja

Naukowa

Język

Angielski

Typ publikacji

Artykuł

Streszczenie

The substitution of the CO ligand in rhodium(I) β-ketoiminato complexes Rh(R1{O,N}R2)(CO)2 ({O,N}=R1C(O)CHC(NH)R2; R1, R2=CF3, Me, CMe3 in several combinations) by phosphorus ligands PZ3 (PZ3=PCy3, PPh3, P(OPh)3, P(NC4H4)3) leads to Rh(R1{O,N}R2)(CO)(PZ3) complexes characterised by 31P{1H}-NMR and X-ray methods. The stronger σ-donor PZ3 ligands (PZ3=PCy3, PPh3) substitute almost exclusively the CO group trans to N, forming P-trans-to-N isomers. The complexes Rh(CF3{O,N}Me)(CO)(PCy3) (II), Rh(CF3{O,N}CMe3)(CO)(PCy3) (III), Rh(CF3{O,N}Me)(CO)(PPh3) (IV) and Rh(CF3{O,N}CMe)(CO)(PPh3) (V) are of a square-planar geometry with a slight tetrahedral distortion around the rhodium atom in II, III and V. The RhP(PCy3) bonds are slightly longer than the RhP(PPh3) bonds. The reaction of stoichiometric amounts of the less basic P(OPh)3 or P(NC4H4)3 ligands leads to the formation of both isomers of the Rh(R1{O,N}R2)(CO)(P(OPh)3) or Rh(R1{O,N}R2)(CO)(P(NC4H4)3) complex in comparable yields. The RhP(P(OPh)3) distance (2.195(2) Å) in the isomer of Rh(CF3{O,N}CMe3)(CO)(P(OPh)3) with P(OPh)3 coordinated trans to N (VI) is ca. 0.04 Å longer than in the isomer of that complex with P(OPh)3 coordinated trans to O (VII). The CO substitution in Rh(R1{O,N}R2)(CO)2 by PZ3 ligands (PPh3, PCy3, P(OPh)3) causes the shortening of the RhC(CO) bond by ca. 0.04 Å compared to Rh(CF3{O,N}Me)(CO)2 (I), making difficult the coordination of another PZ3 ligand, especially one with stronger σ-donor properties. The more π-acceptor P(OPh)3 ligands form bis-phosphito complexes and Rh(CF3{O,N}CMe3){P(OPh)3}2 (VIII) exhibits inequivalence of the two P(OPh)3 ligands in solution (31P-NMR) as well as in solid form (X-ray).The substitution of the CO ligand in rhodium(I) β-ketoiminato complexes Rh(R1C(O)CHC(NH)R2)(CO)2 (R1, R2=CF3, Me, CMe3) by phosphorus ligands PZ3 (PZ3=PPh3, PCy3, P(OPh)3, P(NC4H4)3) leads to Rh(R1C(O)CHC(NH)R2)(CO)(PZ3) complexes of square-planar geometry. The formation of P-trans-to-N isomers is observed for stronger σ-donor, PZ3 ligands (PZ3=PPh3, PCy3) and comparable yields of P-trans-to-N and P-trans-to-O isomers are observed when less basic PZ3, ligands are used (PZ3=P(OPh)3, P(NC4H4)3). The structures of the Rh(R1C(O)CHC(NH)R2)(CO)(PZ3) complexes were confirmed in solution (31P-NMR) and in solid form (X-ray).

Słowa kluczowe

Rhodium(I) complexes, β-Ketoiminato complexes, X-ray, Substitution reaction

Adres publiczny

https://doi.org/10.1016/S0022-328X(01)00805-1

Strona internetowa wydawcy

http://www.elsevier.com

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