A μ-carbido diruthenium(iv) phthalocyanine complex was prepared for the first time from the free-base octabutoxyphthalocyanine by direct metalation with Ru(CO). The first examples of the catalytic activity of Ru(iv) binuclear phthalocyanines were demonstrated by the cyclopropanation of aromatic olefins and carbene insertion into the N-H bonds of aromatic or aliphatic amines with turnover numbers of 680-1000 and 580-1000, respectively.

Series of substituted μ-carbido diruthenium(IV) bisphthalocyaninates [Pc*Ru] 2 (μ-C) [where Pc* = tetra-tert-butyl-, octa-n-butoxy-, tetra-15-crown-5-and hexa-n-butoxy-mono-(15-crown-5)-substituted ligands] were synthesized using two alternative approaches -(i) direct metalation of phthalocyanines with Ru 3 (CO) 12 in refluxing o-dichlorobenzene where [Pc*Ru] 2 (μ-C) are formed as by-products together with monomeric complexes [Pc*Ru](CO) and (ii) dimerization of [Pc*Ru]-(CO) by dichlorocarbene generated in situ from chloroform and [a] 1924 Scheme 3. Synthesis of μ-carbido complexes starting from [Pc*Ru](CO) and dichlorocarbene, generated in situ from CHCl 3 and a base (KOH or NMe 4 OH).

Coordination-induced spin crossover (CISCO) in nickel(II) porphyrinates is an intriguing phenomenon that is interesting from both fundamental and practical standpoints. However, in most cases, realization of this effect requires extensive synthetic protocols or extreme concentrations of extra-ligands. Herein we show that CISCO effect can be prompted for the commonly available nickel(II) tetraphenylporphyrinate, NiTPP, upon deposition of this complex at the air/water interface together with a ruthenium(II) phthalocyaninate, CRPcRu(pyz)2, bearing two axial pyrazine ligands. The latter was used as a molecular guiderail to align Ni···Ru···Ni metal centers for pyrazine coordination upon lateral compression of the system, which helps bring the two macrocycles closer together and forces the formation of Ni–pyz bonds. The fact of Ni(II) porphyrinate switching from low- to high-spin state upon acquiring additional ligands can be conveniently observed in situ via reflection-absorption UV-vis spectroscopy. The reversible nature of this interaction allows for dissociation of Ni–pyz bonds, and thus, change of nickel cation spin state, upon expansion of the monolayer.

A ruthenium phthalocyanine catalyzes the cyclopropanation of olefins (15 substr.) and single carbene insertion into N–H bonds of aromatic, heteroaromatic and aliphatic amines (20 substr.) with high selectivity and under practical reaction conditions.