Structural and Photophysical Characterization of All Five Constitutional Isomers of the Octaethyl-ß,ß'-dioxo-bacterio- and -isobacteriochlorin Series.

It is well-known that treatment of ß-octaethylporphyrin with H2 O2 /conc. H2 SO4 converts it to a ß-oxochlorin as well as all five constitutional isomers of the corresponding ß,ß'-dioxo-derivatives: two bacteriochlorin-type isomers (ß-oxo groups at opposite pyrrolic building blocks) and three isobacteriochlorin-type isomers (ß-oxo-groups at adjacent pyrrolic building blocks). By virtue of the presence of the strongly electronically coupled ß-oxo auxochromes, none of the chromophores are archetypical chlorins, bacteriochlorins, or isobacteriochlorins. Here the authors present, inter alia, the single crystal X-ray structures of all free-base diketone isomers and a comparative description of their UV-vis absorption spectra in neutral and acidic solutions, and fluorescence emission and singlet oxygen photosensitization properties, Magnetic Circular Dichroism (MCD) spectra, and singlet excited state lifetimes. DFT computations uncover underlying tautomeric equilibria and electronic interactions controlling their electronic properties, adding to the understanding of porphyrinoids carrying ß-oxo functionalities. This comparative study lays the basis for their further study and utilization.

Crystal structure of chlorido-[1-(4-nitro-phen-yl)thio-urea-κS]bis-(tri-phenyl-phosphane-κP)silver(I).

In the title compound, [AgCl(C7H7N3O2S)(C18H15P)2], the AgI ion is in a distorted tetra-hedral coordination environment formed by P atoms from two tri-phenyl-phosphane ligands, one terminal S atom from the 1-(4-nitro-phen-yl)thio-urea ligand and a chloride ion. In the crystal, bifurcated (N-H)2⋯Cl hydrogen bonds [with graph-set motif R21(6)] connect complex mol-ecules, forming zigzag chains along [001]. These chains are linked via weak C-H⋯O hydrogen bonds, forming a two-dimensional network parallel to (100). An intra-molecular N-H⋯Cl hydrogen bond forming an S(6) ring is also observed.

Quasi-1D chains of dinickel lantern complexes and their magnetic properties.

Four new quasi-1D Ni2-lantern chain complexes of the form [Ni2(SOCR)4(L)]∞ (R = Ph, L = DABCO (1); R = Ph, L = pyz (2); R = CH3, L = DABCO (3); R = CH3, L = pyz (4)) were prepared from the reaction of [Ni2(SOCR)4(EtOH)], R = CH3 or Ph, with the N,N'-donor bridging ligands pyrazine (pyz) or 1,4-diazabicyclo[2.2.2]octane (DABCO). Reaction of [Ni2(tba)4(EtOH)], (tba = thiobenzoate) with the mono-N donor ligand quinuclidine (quin) gave the discrete Ni2-lantern complex [Ni2(tba)4(quin)] (5), whereas reaction with pyridine led to fragmentation of the lantern and formation of the known [Ni(tba)2(py)2] (6). Single-crystal X-ray diffraction reveals 2-4 to be 1D chain complexes comprising DABCO or pyz ligands which bridge the Ni2-lantern units. Complex 5 forms dimers through two equivalent NiS interactions. The Ni-Ni distances within the Ni2-lanterns are 2.5316(18)-2.595(2) Å for the 1D chain complexes 2-4, and 2.5746(4) Å in the dimeric complex 5, respectively. Comparing the solid state magnetism of 5 to precursor [Ni2(tba)4(EtOH)] demonstrates a change in coupling upon change of capping ligand. Meanwhile, chains 1-4 exhibit magnetic properties consistent with an S = 1 system, due to a mixed valent system where the two Ni centers differ in spin state, while 5 possesses two S = 1 Ni(ii) centers. DFT calculations confirm low-spin S = 0 {NiS4} and high-spin S = 1 {NiO4} centers in each lantern. Fits to the magnetic susceptibility data of the chains suggest a weak antiferromagnetic mean field interaction is present that is largely 1-D in nature, though neither pyrazine nor DABCO promote significant magnetic interaction between neighboring Ni2-lanterns.

Crystal structure of chlorido-[1-(4-nitro-phen-yl)thio-urea-κS]bis-(tri-phenyl-phosphane-κP)copper(I).

The mononuclear mixed-ligand title complex, [CuCl(C7H7N3O2S)(C18H15P)2], displays a distorted tetra-hedral coordination sphere around the CuI atom, with two P atoms from two tri-phenyl-phosphane mol-ecules, one terminal S atom from a 1-(4-nitro-phen-yl)thio-urea mol-ecule and a chloride ion as ligands. An intra-molecular N-H⋯Cl hydrogen bond stabilizes the mol-ecular conformation [graph-set motif R22(6)]. In the crystal, further N-H⋯Cl hydrogen bonds connect individual mol-ecules into zigzag chains parallel to [001]. The chains are linked by weak C-H⋯O hydrogen-bonding inter-actions into a three-dimensional network.

The Nature of the Bridging Anion Controls the Single-Molecule Magnetic Properties of DyX4M 12-Metallacrown-4 Complexes.

A family of DyX4M(12-MCMnIII(N)shi-4) compounds were synthesized and magnetically characterized (X = salicylate, acetate, benzoate, trimethylacetate, M = NaI or KI). The bridging ligands were systematically varied while keeping the remainder of the MC-geometry constant. The type of monovalent cation, necessary for charge balance, was also altered. The dc magnetization and susceptibility of all compounds were similar across the series. Regardless of the identity of the countercation, the Dy(Hsal)4M 12-MC-4 compounds were the only compounds to show frequency-dependent ac magnetic susceptibility, a hallmark of single-molecule magnetism. This indicates that the nature of the bridging ligand in the 12-MCMnIII(N)shi-4 compounds strongly affects the out-of-phase magnetic properties. The SMM behavior appears to correlate with the pKa of the bridging ligand.

Crystal structure of bis-[(acetato-κO)(imidazolidine-2-thione-κS)bis-(tri-phenyl-phosphane-κP)silver(I)] di-µ-imidazol-idine-2-thione-κ(4) S:S-bis-[(imidazol-id-ine-2-thione-κS)bis-(tri-phenyl-phosphane-κP)silver(I)] di-acetate aceto-nitrile disolvate tetra-hydrate.

In the title compound, [Ag2(C3H6N2S)4(C18H15P)2](C2H3O2)2·[Ag(C2H3O2)(C3H6N2S)(C18H15P)2]2·2C2H3N·4H2O, the Ag(I) ion in the mononuclear neutral complex exhibits a distorted tetra-hedral environment with coordination by two P atoms from tri-phenyl-phosphane (PPh3) ligands, one S atom of an imidazolidine-2-thione (etu) ligand and one O atom of an acetate anion. The binuclear cationic complex comprises two inversion-related [Ag(C3H6N2S)2(C18H15P)] units with Ag(I) ions bridged by two S atoms from etu ligands forming a four-membered Ag-S-Ag-S ring. Each Ag(I) ion is coordinated by a P atom of a PPh3 ligand, two S atoms of bridging etu ligands and the terminal S atom of an etu ligand in a distorted tetra-hedral environment. In the crystal, the mononuclear complex is linked to lattice water mol-ecules through O-H⋯O and N-H⋯O hydrogen bonds, forming a chain along [100]. In addition, the binuclear complex mol-ecules are connected to acetate anions and lattice water mol-ecules via O-H⋯O, N-H⋯O and O-H⋯S hydrogen bonds, also along [100].

Chromene-Annulated Bacteriochlorins.

Syntheses and optical properties of mono- and bis-chromene-annulated bacteriochlorins are described. Known monochromene-annulated meso-(pentafluorophenyl)chlorin is susceptible to a regioselective OsO4-mediated dihydroxylation, generating two monochromene-annulated trihydroxybacteriochlorin stereoisomers: either the newly introduced vic-cis-diol functionality is on the same side as the vic-cis-diol moiety the chromene-annulation was based on or on the opposite side. Treatment of the two isomers with heat or base generates different sets of bis-chromene-annulated bacteriochlorin stereo- and regioisomers. Detailed 1D and 2D (1)H and (19)F NMR spectroscopic investigations allowed the characterization of the isomers that formed. The regioselectivity of the second annulation reaction was rationalized computationally on steric grounds. The bacteriochlorin-type optical spectra of the mono- and bis-chromene-annulated bacteriochlorins are modulated as a result of the annulation, with each isomer possessing a unique spectrum, attributed to the effects the regiochemically distinct annulations have on the conformation of the chromophore. The formation of a bis-chromene-annulated chlorin from the bacteriochlorins is also described, including its X-ray crystal structure, revealing some details of the metrics of the chromene-annulated moiety. The vic-diol functionality of monochromene-annulated trihydroxybacteriochlorins is also susceptible to oxidation and ring-expansion reactions, generating chromene-annulated pyrrole-modified chlorins incorporating oxazolone and morpholine moieties. The work expands the body of work on the synthesis and optical fine-tuning of meso-aryl-substituted bacteriochlorins.

Crystal structure of [3-amino-2-(phenyl-diazenyl)-pyridine]chlorido-(η(6)-p-cymene)-ruthenium(II) chloride.

The title compound, [RuCl(C10H14)(C11H10N4)]Cl is an Ru(II) complex in which an η (6) -p-cymene ligand, two N atoms of 3-amino-2-(phenyl-azo)pyridine and one Cl ion form a piano-stool coordination environment around the metal ion. In the crystal structure, N-H⋯Cl hydrogen bonds play an important role in the formation of the supramolecular zigzag chain along the a-axis direction. Disorder is observed for the isopropyl group with site-occupancy factors refined to 0.78 (5) and 0.22 (5).

Crystal structure of tris-[µ2-bis-(di-phenyl-phosphan-yl)methane-κ(2) P:P']di-µ3-iodido-tris-ilver(I) iodide-N-phenyl-thio-urea (1/1).

The title complex, [Ag3I2(C25H22P2)3]I·C7H8N2S, comprises a trinuclear [Ag3I2(C25H22P2)3](+) unit, an I(-) anion and one N,N'-phenyl-thio-urea mol-ecule (ptu). Two µ3-bridging I(-) anions are linked by three Ag(I) ions, leading to the formation of a dicapped triangular motif with Ag⋯Ag separations in the range 3.0823 (5)-3.2999 (5) Å. Each Ag(I) atom exhibits a distorted tetra-hedral geometry, with coordination to two I atoms and two P atoms from bis-(di-phenyl-phosphan-yl)methane ligands. In the crystal, the I(-) anion is linked to the ptu mol-ecule through two N-H⋯I hydrogen bonds [graph-set motif R 2 (1)(6)]. These N-H⋯I hydrogen bonds, in addition to weak C-H⋯S and C-H⋯I hydrogen bonds, form zigzag chains along [010]. Two of the phenyl rings of two dppm ligands are disordered over two sets of sites with refined occupancies of 0.557 (16) and 0.443 (16).

Crystal structure of bis-[µ-1,2-bis-(di-phenyl-phosphan-yl)ethane-κ(2) P:P']bis[(N,N'-di-ethyl-thio-urea-κS)iodidocopper(I)].

The binuclear title complex, [Cu2I2(C26H24P2)2(C5H12N2S)2], lies about an inversion centre. The Cu(I) atom displays a distorted tetra-hedral coordination geometry defined by one S atom of an N,N'-di-ethyl-thio-urea ligand, two P atoms derived from two bridging 1,2-bis-(di-phenyl-phosphan-yl)ethane (dppe) ligands and one iodide ion. The dppe ligand bridges two symmetry-related Cu(I) ions, forming a 10-membered Cu2P4C4 ring. An intra-molecular N-H⋯I hydrogen bond is noted. In the crystal, N-H⋯I hydrogen bonds link complex mol-ecules into layers parallel to (-101).

Indachlorins: nonplanar indanone-annulated chlorin analogues with panchromatic absorption spectra between 300 and 900†nm.

Indaphyrins, pyrrole-modified porphyrins containing a cleaved pyrrole ß,ß'-bond and two annulated indanone moieties, possess unusually broadened and redshifted UV/Vis spectra because of their π-expanded chromophores. The parent free base indaphyrin has been crystallographically characterized, highlighting its strongly ruffled conformation incorporating a helimeric twist. It was shown to be susceptible to regiospecific derivatizations at the opposite side of the ring-cleaved pyrrole (dihydroxylation, followed by functional group transformations of the resulting diol functionality), generating indaphyrin-based chlorin analogues, indachlorins, that incorporate a dihydroxypyrroline, pyrrolindione, oxazolone, or a morpholine moiety. Structural modifications resulted in further broadening and hyper- and bathochromic shifts of the optical spectra, some of which possess a nearly panchromatic absorption between 300 to well above 900 nm. The extents to which these modifications affect their solid-state conformations were analyzed.

Crystal structure of tris-[µ2-bis-(di-phenyl-phosphan-yl)methane-κ(2) P:P']di-µ3-bromido-tris-ilver(I) bromide-N,N'-phenyl-thio-urea (1/1).

The title complex, [Ag3Br2(C25H22P2)3]Br·C7H8N2S, comprises a trinuclear [Ag3Br2(C25H22P2)3](+) unit, a Br(-) anion and one N,N'-di-methyl-thio-urea mol-ecule (ptu). Three Ag(I) ions are linked via two µ3-bridging Br atoms, leading to a distorted triangular bipyramid with an Ag⋯Ag separation range of 3.1046 (6)-3.3556 (6) Å. The triangular Ag3 arrangement is stabilized by six P atoms from three chelating bis-(di-phenyl-phosphan-yl)methane (dppm) ligands. The Ag(I) ion presents a distorted tetra-hedral coordination geometry. In the crystal, the bromide anion is connected to the ptu mol-ecule through N-H⋯Br hydrogen bonds [graph-set motif R 2 (1)(6)]. Each bromide/ptu aggregate links the complex ion via C-H⋯S and C-H⋯Br hydrogen bonds, leading to the formation of a three-dimensional network. Two phenyl rings from two dppm ligands were modelled as disordered over two sites.

Crystal structure of bis-[µ-bis-(di-phenyl-phosphan-yl)methane-κ(2) P:P']-µ-chlorido-chlorido-1κCl-(1-phenyl-thio-urea-2κS)disilver aceto-nitrile hemisolvate.

In the dinuclear title complex, [Ag2Cl2(C7H8N2S)(C25H22P2)2]·0.5CH3CN, each Ag(I) ion displays a distorted tetra-hedral coordination geometry with two P atoms from two bis-(di-phenyl-phosphan-yl)methane (dppm) ligands, one bridging chloride ion, one terminal chloride ion and one terminal S atom from the N,N'-phenyl-thio-urea (ptu) ligand. The dppm ligands and the bridging chloride ion force the two Ag atoms into close proximity, with a short Ag⋯Ag separation of 3.2064 (2) Å. In the crystal, complex mol-ecules are linked by N-H⋯Cl hydrogen bonds forming a dimer. The dimers are linked via weak C- H⋯Cl hydrogen bonds forming a two-dimensional supra-molecular architecture in the yz plane. In addition, an intra-molecular N-H⋯Cl hydrogen bond is observed.

Crystal structure of [1,3-bis-(di-phenyl-phosphan-yl)propane-κ(2) P,P'](N,N'-di-methyl-thio-urea-κS)(thio-cyanato-κN)copper(I).

The asymmetric unit of the title compound, [Cu(NCS)(C3H8N2S)(C27H26P2)], contains two independent mononuclear complex mol-ecules. In each, the Cu(I) ion exhibits a distorted tetra-hedral geometry by coordination with two P atoms from one 1,3-bis(diphenylphosphino)propane (dppm) ligand, one terminal S atom of one N,N'-di-methyl-thio-urea (dmtu) ligand and one terminal N atom of the thio-cyanato ligand. The dppp ligand is involved in a bidentate coordination mode with the Cu(I) ion, forming a six-membered CuP2C3 ring. In both mol-ecules, the coordination of the dmtu ligand is further stabilized by an intra-molecular N-H⋯N hydrogen bond with an S(6) graph-set motif. In the crystal, mol-ecules are linked by N-H⋯S hydrogen bonds forming a zigzag chain along the a-axis direction. In one independent mol-ecule, one of the phenyl rings of the dppp ligand is disordered over two sites with refined occupancies 0.639 (11):0.361 (11) and this corresponds with a mutual disorder of the dmtu ligand in the other independent mol-ecule giving the same ratio of refined occupancies. The structure was refined as a two-component inversion twin.