TY - JOUR

T1 - 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

AU - Varshavsky, Yuri S.

AU - Galding, Margarita R.

AU - Cherkasova, Tatiana G.

AU - Podkorytov, Ivan S.

AU - Nikol'Skii, Alexey B.

AU - Trzeciak, Anna M.

AU - Olejnik, Zofia

AU - Lis, Tadeusz

AU - Ziólkowski, Józef J.

N1 - Funding Information: The authors from St. Petersburg State University are grateful to the Education Ministry of Russian Federation for financial support (grant 98-8-4.1-14). A.M.T. and J.J.Z. thank the State Committee for Research (KBN) for financial support; project PBZ-KBN 15/09/T09/99/01d. Free β-ketoamines and their copper(II) complexes, Cu(β-ketim) 2 , were kindly furnished by K.I. Pashkevich and V.I. Filjakova (the Institute of Organic Synthesis of the Ural branch of the Russian Academy of Science, Ekaterinburg), whose contribution is gratefully acknowledged.

PY - 2001/5/26

Y1 - 2001/5/26

N2 - 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).

AB - 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).

KW - β-Ketoiminato complexes

KW - Rhodium(I) complexes

KW - Substitution reaction

KW - X-ray

UR - http://www.scopus.com/inward/record.url?scp=0041402713&partnerID=8YFLogxK

U2 - 10.1016/S0022-328X(01)00805-1

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

M3 - Article

AN - SCOPUS:0041402713

VL - 628

SP - 195

EP - 210

JO - Journal of Organometallic Chemistry

JF - Journal of Organometallic Chemistry

SN - 0022-328X

IS - 2

ER -