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Rhodium(I) Complexes of N ‐Aryl‐Substituted Mono‐ and Bis(amidinates) Derived from Their Alkali Metal Salts
Author(s) -
Moos Eric M. B.,
GonzálezGallardo Sandra,
Radius Michael,
Breher Frank
Publication year - 2018
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201800349
Subject(s) - chemistry , deprotonation , rhodium , alkali metal , medicinal chemistry , alkyne , carbonylation , synthon , aryl , metal , metalation , heteroatom , stereochemistry , catalysis , organic chemistry , carbon monoxide , ion , alkyl , ring (chemistry)
The synthesis and characterization of several rhodium(I) complexes of amidinate and linker‐bridged bis(amidinate) ligands are presented. The amidinate ligands for the mononuclear complexes CH 3 {C(NMes) 2 Rh(cod)} ( 1 ), CH 3 {C(NDipp) 2 Rh(cod)} ( 2 ), and HCC{C(NDipp) 2 Rh(cod)} ( 3 ) (cod = 1,5‐cyclooctadiene) were synthesized by reacting the corresponding organometallic precursor [Rh(cod)Cl] 2 with the alkali metal amidinates CH 3 {C(NR) 2 Li} L1Li (R = Mes = 2,4,6‐Me 3 C 6 H 2 ) and L2Li (R = Dipp = 2,6‐ i Pr 2 C 6 H 3 ). Analogously, the alkynyl‐functionalized sodium amidinate (HCC{C(NDipp) 2 Na} · 2DME, L3Na ) could be further deprotonated and reacted with carbodiimine to form the alkyne‐bridged bis(amidinate) CC{C(NDipp) 2 Na(thf)} 2 ( L4Na ), which serves as suitable starting material for the synthesis of CC{C(NDipp) 2 Rh(cod)} 2 ( 4 ). The bis(amidinate) ligands for the corresponding para ‐ ( 5 ) and meta ‐ ( 6 ) phenylene‐bridged complexes p ‐/ m ‐C 6 H 4 {C(NMes) 2 Rh(cod)} 2 were accessible through the reaction of phthalic acids with trimethylsilyl polyphosphate and mesitylamine and subsequent deprotonation of the obtained amidines. Tetramesityl oxalamidinate was used to synthesize the dinuclear complex {C(NMes) 2 Rh(cod)} 2 ( 7 ) and its carbonylation product {C(NMes) 2 Rh(CO) 2 } 2 ( 8 ). All compounds under study were fully characterized by various spectroscopic methods. In particular the alkali metal salt of the linker‐bridged bis(amidinate) L5Na forms a one‐dimensional coordination polymer in the solid state. Reaction of L5Na and L6Na with [Rh(cod)Cl] 2 leads to dinuclear complexes in which the metal–metal distance can be adjusted, enabling us to study their reactivity, including possible cooperative effects in catalysis.