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The cis-dichloro-meso-hexaethylporphodimethene−zirconium(IV) complex has been functionalized to the corresponding dialkyl derivatives [R = Me, PhCH2, Ph], 3−5, displaying a variety of migratory pathways. In the case of benzyl derivative 4, the spontaneous migration of the first benzyl to the ligand, 6, is followed by the second one, photochemically induced, thus forming a Zr−porphyrinogen complex, 7. The methyl derivative undergoes thermally induced methane elimination with the metalation of the meso ethyl chains, 8. Migration of both methyl groups has been observed in the reaction of 3 with Bu^tNC, with the preliminary formation of η²-imine, rearranging to the corresponding enamine, 9.

The (meso-octaethylporphyrinogenato)zirconium(IV) species [(Et8N4)Zr(thf)] (1) binds the acetophenone potassium enolate [PhCOCH2K] (2) in its ion-pair form, [(η⁵:η¹:η¹:η¹-Et8N4)Zr{PhC(CH2)O}K(thf)3] (3), and thus drives the aldol condensation reaction with acetophenone. The resulting aldolate, which occurs in a metallacyclic form due to the solvation of potassium by a phenyl ring, remains η¹ (O)-bonded to zirconium, [(η⁵:η¹:η¹:η¹-Et8N4)Zr{PhC(CH2)OC(O)C(Me)Ph}K]n (4).

The reaction of a Ti&sbd;Me species with carbon monoxide occurred with the complete cleavage of the C&sbd;O bond and formation of the Ti&dbd;O unit, while the [Me&sbd;C] fragment homologated a pyrrole to a 4-methylpyridine ring within the meso-octaethyl tris(pyrrole)−mono(pyridine) macrocycle.

[(Calix[4]OMe)TaCl2] (2), formed from [calix[4](OMe)2] (1) and TaCl5 via a demethylation reaction, undergoes exhaustive alkylation to [(calix[4]OMe)TaR2] (3−5), which give photochemically or thermally induced concerted dealkylation at the metal and at the methoxy group, to give [calix[4]TaR] (6−8). Double migration of alkyl groups has been observed in the reaction of 3−5 with CO and Bu^tNC to form the corresponding η²-ketones [(calix[4]OMe)Ta(η²-COR2)] (9−11) and η²-imines [(calix[4]OMe)Ta{η²-N(Bu^t)CR2}] (12−14).

A reactive coordinatively unsaturated iron(II) bonded to a quasi-planar O4 environment in [calix[4](OMe)2(O)2Fe] (2) has been obtained from the reaction of the free ligand 1 with Fe2Mes4 (Mes = 1,3,5-Me3C6H2). The reaction of 2, which adds a variety of monodentate ligands, [calix[4](OMe)2(O)2FeL] (L = thf, 3; Bu^tNC, 4), with Ph2CN2 led to the first high-spin iron(II) carbene bonded to an oxo matrix, [calix[4](OMe)2(O)2Fe&dbd;CPh2] (5).

The doubly homologated meso-octaethylporphyrinogen 1, containing two pyridine and two pyrrole rings in cis arrangements, allowed the synthesis of highly reactive vanadium(III) organometallics, via the intermediacy of 2, [Et8(m-MeC5H2N)(C5H3N)(C4H2N)2Li2(THF)2], and 3, [Et8(m-MeC5H2N)(C5H3N)(C4H2N)2V−Cl]. This latter complex has been converted to the corresponding [V−Me] derivative 4, [Et8(m-MeC5H2N)(C5H3N)(C4H2N)2V−Me], which undergoes a facile carbonylation to 5, Et6(m-MeC5H2N)(C5H3N)(C4H2N)2V−OC(CEt2)(Me)]. The intermediate η²-acyl derivative thus found displayed an unusual carbenoid reactivity inserting into a C−C bond.

Elemental sulfur reacts with the Co(II) Schiff‐base complexes (I) in coordinating solvents to afford binuclear, diamagnetic Co(III) complexes (IV), (V) and (VII) containing a tetrasulfido bridging ligand.

The reaction of sodium guaiacolate (II) with the V(III)‐chloride (I) leads to the air‐sensible, binuclear V(III) complexes (III) and (IV) depending on the stoichiometric ratio.