A Square‐Planar Ruthenium(II) Complex with a Low‐Spin Configuration

Abstract

Ground‐about: The ruthenium(II) complex [RuCl{N(CH2CH2PtBu2)2}] (B) is obtained in high yield by the reaction of [RuCl2{HN(CH2CH2PtBu2)2}] (A) with KOtBu. Complex B exhibits an unusual electronic low‐spin (S=0) ground‐state configuration. Comparison with Caulton's [RuCl{N(SiMe2CH2PtBu2)2}] (ground state: S=1) shows that the ground‐state spin multiplicity in these complexes is controlled by the N→Ru π‐donor strength.

Square‐Planar Iridium(II) and Iridium(III) Amido Complexes Stabilized by a PNP Pincer Ligand

“…[9,10] However, the stronger N!M p donation in the related dialkylamido complex [RuCl(L 1 )] (R = tBu) results in a low-spin ground state. [11] These examples demonstrate the importance to rationalize the parameters that control the electronic structure and therefore the reactivity of such radical complexes and coordinatively strongly unsaturated complexes of the platinum metals. Regarding the PNP pincer ligands used in our group (Scheme 1), the dehydrogenation of one of the chelate backbone ethylene bridges to ligand L 3 allows the donor properties to be fine-tuned.…”

“…Therefore, the unusual electronic low-spin configuration of 2 is attributed to strong N!Ir p donation as in the case of [RuCl(L 1 )] (R = tBu). [11] While the p-donor properties of the L 1 ligand should be weakened by dehydrogenation to L 4 , this effect is counterbalanced by the cationic charge and the change from a 4d to a 5d metal, which should strengthen M À N bonding. [24] In conclusion, simple oxidative ligand functionalization of the PNP chelate ligand framework allows for the versatile isolation of unusual square-planar d 7 und d 6 iridium complexes.…”

Quadratisch‐planare Iridium(II)‐ und Iridium(III)‐Amidokomplexe mit einem PNP‐Pinzettenliganden

“…[9,10] Die stärkere N!M-p-Donierung beim verwandten Dialkylamidokomplex [RuCl(L 1 )] (R = tBu) führt dagegen zum Low-Spin-Grundzustand. [11] Diese [Ir(H)Cl(C 8 H 13 )(HL 1 )] (3; R = tBu) [13] wird in situ mit Benzochinon (2.5 ¾quiv.) zum türkisfarbenen 1 in Ausbeuten an isoliertem Produkt von bis zu 60 % oxidiert (Schema 2).…”

“…Die ungewçhnliche elektronische Low-Spin-Konfiguration von 2 ist somit wie bei [RuCl(L 1 )] (R = tBu) auf starke N!Ir-p-Donierung zurück-zuführen. [11] Während diese durch Oxidation des L 1 -zum L 4 -Liganden abgeschwächt werden sollte, ist zu erwarten, dass die kationische Ladung und der Wechsel zum 5d-Metall die M-N-Bindung stärken. [24] Zusammenfassend gelingt durch einfache oxidative Ligandmodifikation des PNP-Chelatliganden die Isolierung quadratisch-planarer d 7 [7,25] Somit erçffnet der …”

Iron, ruthenium and osmium

“…80 Photolysis of the chlorates [Ru(porphyrin)(OClO 2 ) 2 ] generates the trans-dioxoruthenium(VI) species [RuO 2 (porphyrin)] (porphyrin e.g. 80 Photolysis of the chlorates [Ru(porphyrin)(OClO 2 ) 2 ] generates the trans-dioxoruthenium(VI) species [RuO 2 (porphyrin)] (porphyrin e.g.…”