Paramagnetic One-Dimensional Chains Comprised of Trinuclear Pt–Cu–Pt and Paddlewheel Dirhodium Complexes with Metal–Metal Bonds

Abstract

One-dimensional (1-D) chain complexes constructed by metal-metal bonds containing three types of metal species-platinum, rhodium, and copper-have been rationally synthesized and characterized by single-crystal X-ray analyses and physical measurements. The paddlewheel or lantern type complex, [Rh2(O2CCH3)4] (i.e., [Rh2]), has a vacant σ* orbital which accepts the electrons from the filled dz(2) orbital of cis-[Pt(piam)2(NH3)2]·2H2O (1, i.e. [Pt], where piam = pivalamidate) to afford a tetranuclear complex, [{Rh2(O2CCH3)4}{Pt(piam)2(NH3)2}2]·2H2O (2). Compound 2 forms a linear alignment as [Pt]-[Rh2]-[Pt] with unbridged Rh-Pt bonds, where the oxygen atoms of the piam ligands in the [Pt] are noncoordinated, showing the capability of binding another metal ion. Simply mixing [Rh2] and the heterometallic trinuclear complex [Pt2Cu(piam)4(NH3)4](PF6)2 (3, i.e. [Pt-Cu-Pt]) in a ratio of 1:1 in MeOH, EtOH, or Me2CO affords [{Rh2(O2CCH3)4}{Pt2Cu(piam)4(NH3)4}]n(PF6)2n (4), [{Rh2(O2CCH3)4}{Pt2Cu(piam)4(NH3)4}]n(PF6)2n (5), or [{Rh2(O2CCH3)4}{Pt2Cu(piam)4(NH3)4}]n(PF6)2n·6nMe2CO (6), respectively. Compounds 4-6 form infinite chains with the repetition of -{[Rh2]-[Pt-Cu-Pt]}n-, which to our knowledge, are the first examples of heterometallic 1-D chains comprised of three types of metal species with direct metal-metal bonds. The CF3CO2(-), ClO4(-), and water molecules influence the crystal packing to form an octanuclear complex of [{Rh2(O2CCH3)4}{Pt2Cu(piam)4(NH3)4}2](CF3CO2)2(ClO4)2·2H2O (7) with [Pt-Cu-Pt]-[Rh2]-[Pt-Cu-Pt] alignment. Considering the crystal structures and X-ray photoelectron spectra (XPS) measurements in 4-7, the oxidation states of the metal atoms are -{[Rh2(II,II)]-[Pt(II)-Cu(II)-Pt(II)]}n- or [Pt(II)-Cu(II)-Pt(II)]-[Rh2(II,II)]-[Pt(II)-Cu(II)-Pt(II)], which are unchanged from those in the starting compounds. Electron paramagnetic resonance spectra of 4-7 show axially symmetric spectra with g∥ > g⊥, indicating that the HOMO (SOMO) is a Cu d(x(2)-y(2)) orbital. In 7, the hyperfine coupling in the spectrum indicates that the unpaired spin on Cu is perturbed by the Pt atoms.

Linear One-Dimensional Coordination Polymers Constructed by Dirhodium Paddlewheel and Tetracyanido-Metallate Building Blocks

“…An interesting approach to obtain this kind of heterometallic one-dimensional polymers is the use of platinum complexes to form {[Rh 2 ]-[Pt 2 ]-[Pt 2 ]} n chains, in which the different dimetallic units show direct Rh-Pt metal-metal bonds [26][27][28][29]. Paramagnetic [Rh 2 ]-[Pt-Cu-Pt] chains can be synthesized, also inserting a copper complex [30,31]. In addition, several heterometallic one-dimensional polymers using dicyanidoaurate, [Au(CN) 2 ] − [32], or dicyanidoargentate, [Ag(CN) 2 ] − [33], as bridging axial ligands have been reported by our research group.…”

Control of Metal Arrays Based on Heterometallics Masquerading in Heterochiral Aggregations of Chiral Clothespin‐Shaped Complexes

“…All the experimentalr esults obtained from the 1 HNMR spectroscopy,H PLC, and EPMA analyses of various multicomponent gels clearly indicated that the incorporation of 1a and 1b units into the gel fibers proceeded in as trict heterochiral manner without any homo or heterometallic influence on the molecular alignment, and that the component ratios in gels were not altered by the application of ultrasound irradiation. Given that previous studies concerning metal arrangements and aggregations have employed metal core-based control utilizing metal-ligand [1][2][3][4] and metal-metal [5] interactions, we can be reasonably certain that the presentr esults represent an unprecedented example of the arrangement of metals in which the shape of the organic shell/ligand is the sole controlling factor and different metals are masqueraded based on this shell-controlled aggregation.B yu tilizing the principle of the present heterochiral aggregation,w ec an tune the metal array fabrication to an extraordinarily high level of regularity such that one side of the chiral units is fixed to as ingle metallic 12 ]cyclohexane (a,c,e ,g, i) or cyclohexane (b, d, f, h, j) at 298 K. Gelationc onditions: a, b) (+ +)-1a (2.0 10 À4 m)/(À)-1b (2.0 10 À4 m)(1:1) without sonication; c, d) (+ +)-1a (1.33 10 À4 m)/(À)-1a (1.33 10 À4 m)/(+ +)-1b (1.3310 À4 m)( 1:1:1) just after pre-sonication (44 kHz, 0.31 Wcm À2 ,s ine wave, 5s); e, f) (+ +)-1a (1.6 10 À4 m)/(À)-1a (1.6 10 À4 m)/ (+ +)-1b (8.0 10 À5 m)( 2:2:1) just after pre-sonication( 44 kHz, 0.31 Wcm À2 , sine wave, 5s); g, h) (+ +)-1a (1.33 10 À4 m)/(+ +)-1b (1.33 10 À4 m)/(À)-1b (1.33 10 À4 m)(1:1:1) without sonication;i ,j)(+ +)-1a (8.0 10 À5 m)/(+ +)-1b (1.6 10 À4 m)/(À)-1b (1.6 10 À4 m)( 1:2:2) without sonication. Red circles: (+ +)-1a;red squares;(À)-1a;blue circles:(+ +)-1b;blue squares:( À)-1b.D ata were acquiredb yu sing 1 HNMR spectroscopy (a, b) and HPLC (c-j) analyses.…”

“…An important alternative strategyf or the creation of metal arrays involves utilizing metallophilic interactionsb etween various p-acidica nd basic transition metals to afford both discrete and infinite linear arrangementmodes. [5] Control over the supramolecular order of the aggregating units has been investigated as an alternative but promising approach to metal array fabrication. [6] The heterolytic arrangement of small molecules in aggregationf ibers is af ascinating aspect of supramolecular chemistry, [7] although precise control over the molecular order remains challenging.…”

Heteronuclear Dirhodium-Gold Anionic Complexes: Polymeric Chains and Discrete Units

“…Several approaches can be found in the literature to obtain heterometallic one-dimensional polymers where different metal complexes connect the dirhodium units [ 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 ]. The valuable physicochemical properties of some of them, like paramagnetism [ 42 , 47 ], modulation of their electronic structures [ 43 ], or luminescence [ 49 ], turn this kind of polymers into very promising materials. However, the number of heterometallic coordination polymers based on rhodium(II) carboxylates is still scarce.…”