(Eta5-pentamethylcyclopentadienyl)rhodium and -iridium complexes with weakly and strongly coordinating anions: isolation and first X-ray molecular structures of the tris(solvent) complexes [(C5Me5)M(acetone)2(H2O)][BF4]2 (M = Rh, Ir)

Several novel pentamethylcyclopentadienyl complexes of general formula [(C5Me5)IrL3][BF4]2 were prepared including the tris(solvent) precursors [(C5Me5)M(acetone)2(H2O)][BF4]2 (M = Rh, Ir) (1a,b). The X-ray molecular structures of 1a,b were determined at low temperature. Complexes 1a,b are isostructural, and both compounds crystallize in the monoclinic space group P2(1)/c with a = 10.157(3) A, b = 14.038(9) A, c = 16.335(2) A, beta = 99.73(2) degrees, and Z = 4 for 1a and with a = 10.107(9) A, b = 13.994(16) A, c = 15.996(34) A, beta = 99.61(12) degrees, and Z = 4 for 1b. The coordinated water molecule is hydrogen bonded to both BF4(-) anions. Reaction of 1a,b with pyridine (py) afforded the related tris(pyridine) complexes [(C5Me5)M(eta1-(N)-py)3][BF4]2 (M = Rh, Ir) (2a,b). Complex 2b was characterized by X-ray crystallography, monoclinic space group P2(1)/c with a = 8.665(3) A, b = 19.687(7) A, c = 18.408(5) A, beta = 94.17(3) degrees, and Z = 4. Moreover, we prepared the novel neutral compounds (C5Me5)M(eta2-NO3)(eta1-NO3) (M = Rh, Ir) (4a,b) where the anions are bonded to the metal center instead of a coordinating solvent as confirmed by X-ray study on the iridium complex 4b. The latter crystallizes in the orthorhombic space group Pcab with a = 13.032(4) A, b = 14.370(11) A, c = 14.839(18) A, and Z = 8.     

Highly Phosphorescent Crystals of Square‐Planar Platinum Complexes with Chiral Organometallic Linkers: Homochiral versus Heterochiral Arrangements,Induced Circular Dichroism,and TD‐DFT Calculations

A novel class of chiral luminescent square‐planar platinum complexes with a π‐bonded chiral thioquinonoid ligand is described. Remarkably the presence of this chiral organometallic ligand controls the aggregation of this square planar luminophor and imposes a homo‐ or hetero‐chiral arrangement at the supramolecular level, displaying non‐covalent Pt–Pt and π–π interactions. Interestingly these complexes are highly luminescent in the crystalline state and their photophysical properties can be traced to their aggregation in the solid state. A TD‐DFT calculation is obtained to rationalize this unique behavior.     

Supramolecular assemblies based on organometallic quinonoid linkers: a new class of coordination networks

Self-assembly of coordination frameworks exhibiting original architectures is an active area of research. Generally, such assemblies are constructed from organic spacers and transition metals of different geometrical structures. Herein, we report a novel class of supramolecular coordination assemblies with organometallic linkers based on metalated quinonoid and thioquinonoid complexes that serve as spacers. The organometallic ligands are stable and have the general formula [Cp*M(eta(4)-benzoquinone)] (o- and p-benzoquinone, Cp*=C(5)Me(5), M=Rh, Ir) and [Cp*Ir(eta(4)-thiobenzoquinone)] (o- and p-thiobenzoquinone). These units bind through both oxygen or sulfur atoms to metal ions of different coordination geometry, such as Cu(I), Ag(I), and Pt(II), to generate supramolecular coordination networks, with the metalated quinonoid or thioquinonoid linkers acting as backbones and the metal centers as nodes. This novel family of supramolecular assemblies exhibits short pi-pi and MM interactions. These results illustrate successfully the role of the organometallic linkers to produce an impressive range of novel supramolecular architectures that hold promise for the development of functional materials.     

cis-trans photoisomerization in [Ru(DIP)2(MeOH)2][OTf]2: synthesis, NMR, X-ray structure of the trans-isomer and photophysical properties

The first trans-ruthenium complex trans-[Ru(DIP)2(MeOH)2][OTf]2 (1b, where DIP = 4,7-diphenyl-1,10-phenanthroline) incorporating a pi-extended ligand was prepared via two methods: either photolysis of cis-[Ru(DIP)2(OTf)2] in MeOH-Et(2)O or via crystallization from MeOH-Et(2)O in direct sunlight. The X-ray molecular structure of is reported and confirmed the trans geometry of the title compound. The cis-trans isomerization process was monitored by 1H-NMR and showed that 1b reverts back to cis-[Ru(DIP)2(MeOH)2][OTf]2 (1a) in methanol-d4 after 15 h at 55 degrees C or several days at room temperature. The absorption spectra recorded in MeOH showed a bathochromic shift of the MLCT band of the trans-isomer 1b relative to that of the cis complex 1a. Interestingly at 77 K the emission spectrum of 1b is red shifted compared to the cis analog 1a. A rational explanation in terms of the energy of the excited states in the cis- and trans-isomers is proposed to explain this behavior.     

A new family of mono- and dicarboxylic ruthenium complexes [Ru(DIP)2(L2)]2+ (DIP = 4,7-diphenyl-1,10-phenanthroline): synthesis, solution behavior, and X-ray molecular structure of trans-[Ru(DIP)2(MeOH)2][OTf]2

A new family of ruthenium complexes of general formula [Ru(DIP)2(L2)]2+, where DIP = 4,7-diphenyl-1,10-phenanthroline, a bidentate ligand with an extended aromatic system, was prepared and fully characterized. When L is a monodentate ligand, the following complexes were obtained: L = CF3SO3(-1) (2), CH3CN (3), and MeOH (4). When L2 is a bidentate ligand, the compounds [Ru(DIP)2(Hcmbpy)][Cl]2 (5) and [Ru(DIP)2(H2dcbpy)][Cl]2 (6) were prepared (Hcmbpy = 4-carboxy-4'-methyl-2,2-bipyridine, H2dcbpy = 4,4'-dicarboxy-2,2'-bipyridine). Complex [Ru(DIP)2(MeOH)2][OTf]2 (4) displayed a trans configuration of the DIP ligands, which is rare for octahedral complexes featuring DIP bidentate ligands. DFT calculations carried out on 4 showed that the cis isomer is more stable by 12.2 kcal/mol relative to the trans species. The solution behaviors of monocarboxylic complex [Ru(DIP)2(Hcmbpy)][Cl]2 (5) and dicarboxylic complex [Ru(DIP)2(H2dcbpy)][Cl]2 (6) were investigated by 1H NMR spectroscopy. VT-NMR, concentration dependence, and reaction with NaOD allowed us to suggest that aggregation of the cationic species in solution, especially for 6, originates mainly from hydrogen bonding interactions.     

Crucial role of the counteranion on the templation of metallomacrocycles and a 3D network: synthesis,characterization, and structural analysis

Two novel supramolecular architectures, [[Ag(2)L(1)(2)][X](2)] with X = CF(3)SO(3)(-) (2a) or X = NO(3)(-) (2b) and [[AgL(1)(2)][X]](n) with X = BF(4)(-) (3), were constructed by self-assembly and obtained in quantitative yields, using AgX as a building block and L(1) as the bridging ligand (L(1) = 1,3-bis(benzimidazol-1-ylmethyl)benzene). The X-ray molecular structures of 2a and 3 are reported. Complex 2a was identified as a metallomacrocycle in which one ligating triflate anion is coordinated to each of the two unsaturated Ag(I) ions. 2a crystallizes in monoclinic unit cell P2(1)/n with a = 9.728(6) A, b = 17.303(4) A, c = 13.268(3) A, beta = 92.52(4) degrees, V = 2231(2) A(3), and Z = 2. Remarkably, the X-ray structure of 2a shows a layered network structure consisting of infinite metallomacrocycles held together through pi-pi interactions between benzimidazole rings. In dramatic contrast, the product 3 prepared from AgBF(4) and L(1) lacks metal-counterion bonding, leading to a supramolecular 3D network with the following three outstanding features: (i) in one dimension, metallomacrocycles containing two Ag centers and two bridging ligands form infinite, double-stranded chains; (ii) neighboring chains are arranged by two distinct pi-pi interactions, one between substituted benzene rings and the other between benzimidazole rings, leading to a 3D structure; (iii) cavities within the 3D network contain BF(4)(-) counteranions. 3 crystallizes in monoclinic unit cell C2/c with a = 25.33(3) A, b = 11.655(6) A, c = 18.466(8) A, beta = 123.00(8) degrees, V = 4572(8) A(3), and Z = 4. Interestingly, electrospray mass spectroscopy suggests in either case that the identified elemental subunit [AgL(1)(2)](+) is the key building block which self-assembles and subsequent anion templation provides either the macrocycles 2a, b or the inorganic polymer 3. Remarkably, in dichloromethane solvent ligand-to-metal stoichiometries of 2:1 in 3 and 1:1 in 2a, b are obtained even with excess ligand, showing the power of metal-anion interactions in determining the overall supramolecular structure. Anion metathesis, showing supramolecular structural rearrangements from 2a to 2b and more spectacularly from 3 to 2b, smoothly occurred. The crucial effect and the nature of coordinating counteranions (BF(4)(-), CF(3)SO(3)(-), NO(3)(-)) on the supermolecule design are presented and discussed.