Organometallic–Inorganic Conjugated Unsymmetrical Schiff-Base Hybrids. Synthesis, Characterization, Electrochemistry and X-ray Crystal Structures of Functionalized Trinuclear Iron–Nickel–Ruthenium Dipolar Chromophores

Side‐Chain Metallopolymers Containing Second‐Order NLO‐Active Bimetallic NiII and PdII Schiff‐Base Complexes: Syntheses, Structures, Electrochemical and Computational Studies

“…The bond lengths between the metal center and neighboring donor atoms range from 1.837(6) and 1.873(4) Å in 3 , and from 1.953(5) and 2.027(4) Å in 4 (Table ). These values are unexceptional and are in agreement with those previously reported for nickel(II) and palladium(II) acyclic Schiff‐base complexes , , ,. [26a], Interatomic O–C, C–C and C–N bond lengths measured between single and double bond lengths, and bond angles close to 120° (Table ) of the chelating Schiff‐base ligand suggest substantial delocalization of the electron density throughout the entire π‐conjugated system.…”

“…This increased difficulty in oxidizing the Fe II center with respect to free ferrocene is due to the electron‐withdrawing nature of the side‐chain [M(N 2 O 2 )] Schiff‐base substituent. The Δ E 1/2 of 0.12 and 0.17 V found for 2 and 3 , respectively, corroborate what we observed previously with ferrocene‐containing diprotonated N 2 O 2 macrocycles and their four‐coordinate Ni II and Cu II derivatives, [26a] Interestingly, in the case of Pd II complex 4 , the much larger anodic shift of 0.24 V (Table and Figure S8 in the Supporting Information) clearly indicates that this second row transition‐metal ion greatly facilitates electronic communication between the donor and acceptor elements of the molecule. It is also likely that the Pd II center plays an electro‐attractive effect because of its higher electropositivity (see the Theor.…”

“…The more salient features of the solid‐state IR spectra of compounds 2 – 4 is the presence of a set of medium to strong intensity bands in the 1655–1555 cm –1 region, attributed to the ν (CO), ν (CC) and ν (CN) stretching vibrations of the organic Schiff‐base skeleton (Figures S1 and S2 in Supporting Information) . The disappearance of the weak ν (N–H) absorption (observed in the spectrum of 2 at 3256 cm –1 ) in the spectra of complexes 3 and 4 indicates that the acyclic [N 2 O 2 ] 2– ligand is bonded to the nickel(II) and palladium(II) ion, respectively, in its dianionic form.…”

Molecular and Solid State Structure of the Doubly-Substituted B-Diketone 3,3'-Bis(ferrocenylmethyl)pentane-2,4-Dione#

“…Both compounds 1 and 2, that are air and thermally stable, were previously obtained by Glidewel et al; 29 1 was isolated in 78% yield upon refluxing equimolar quantities of ferrocenylmethyl-trimethylammonium iodide and the monosodium salt of the acetylacetone in dry acetonitrile for 15 h, whereas crystals of 2 deposited when the oil 1 was kept for six months. In addition to the reported analytical and spectroscopic characterization of 2, 15 we provide here the full details of its crystalline structure determination. 34 Figure 1.…”

“…7,8 On the other hand, β-diketones are attractive building blocks for the construction of polydentate Schiff bases, and both the parent derivative 2,4-pentanedione (CH 3 COCH 2 COCH 3 ), [9][10][11][12] and its organometallic counterpart ferrocenoylacetone (FcCOCH 2 COCH 3 , 13 Fc = (h 5 -C 5 H 5 )Fe(h 5 -C 5 H 4 )) have been widely employed to prepare tridentate Schiff base complexes, also called half-units, upon mono-condensation with primary diamines. [14][15][16][17][18][19][20][21][22] In pursuit of our research work aimed at extending the scope of acyclic Schiff base metalloligands, [14][15][16][17] we decided to synthetize new β-diketones functionalized at the central carbon of the 1,3-dione system, using cerium(IV) ammonium nitrate (CAN), a versatile reagent in a variety of synthetic transformations through oxidation of organic molecules, [23][24][25] as catalyst in the carbon-carbon bond formation between ferrocenyl alcohol substrates and 1,3-diketones. 26 Accordingly, we were able to isolate and structurally characterize three new chiral ferrocene-containing diketones starting from 1-ferrocenyl ethanol.…”