A series of Cu(I) mixed-ligand complexes containing dmp (2,9-dimethyl-1,10-phenanthroline) and one of simple diphosphine ligands (Ph2P(CH2)nPPh2) were prepared. Among the complexes, [Cu(dppp)(dmp)]PF6 (n=3) and [Cu2(dppb)2(dmp)2](PF6)2 (n=4) were characterized by X-ray structure analyses. The dppp complex has been characterized as a mononuclear complex, while [Cu2(dppb)2(dmp)2]2+ exists as a dinuclear complex in which two dppb ligands bridge between the two Cu(I) atoms. Although the distorted tetrahedral structures around the central metals of the two complexes are similar, the P-Cu-P angles are different between the two complexes. All of the series of complexes show photoluminescence in solution, and the intensity of the luminescence increases with n (n=2-4). The non-radiative rate constants of the complexes decrease markedly with n although radiative rate constants of the complexes are similar.

Photoluminescent coordination nanosheets (CONASHs) comprising three-way terpyridine (tpy) ligands and zinc(II) ions are created by allowing the two constitutive components to react with each other at a liquid/liquid interface. Taking advantage of bottom-up CONASHs, or flexibility in organic ligand design and coordination modes, we demonstrate the diversity of the tpy-zinc(II) CONASH in structures and photofunctions. A combination of 1,3,5-tris[4-(4'-2,2':6',2″-terpyridyl)phenyl]benzene (1) and Zn(BF) affords a cationic CONASH featuring the bis(tpy)Zn complex motif (1-Zn), while substitution of the zinc source with ZnSO realizes a charge-neutral CONASH with the [Zn(μ-OSO)(tpy)] motif [1-Zn(SO)]. The difference stems from the use of noncoordinating (BF) or coordinating and bridging (SO) anions. The change in the coordination mode alters the luminescence (480 nm blue in 1-Zn; 552 nm yellow in 1-Zn(SO)). The photophysical property also differs in that 1-Zn(SO) shows solvatoluminochromism, whereas 1-Zn does not. Photoluminescence is also modulated by the tpy ligand structure. 2-Zn contains triarylamine-centered terpyridine ligand 2 and features the bis(tpy)Zn motif; its emission is substantially red-shifted (590 nm orange) compared with that of 1-Zn. CONASHs 1-Zn and 2-Zn possess cationic nanosheet frameworks with counteranions (BF), and thereby feature anion exchange capacities. Indeed, anionic xanthene dyes were taken up by these nanosheets, which undergo quasi-quantitative exciton migration from the host CONASH. This series of studies shows tpy-zinc(II) CONASHs as promising potential photofunctional nanomaterials.

The Ag(I) complex with o-bis(diphenylphosphino)benzene shows reversible interconversion between blue-emitting (1b) and green-emitting (1g) materials on grinding and heating; comparison of the structure of 1b with another green-emitting crystals (2) having the same formula suggests the chromism results from intermolecular interactions between adjacent phenylene rings.

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Eight new crystalline α-pyrrolidinonate-bridged homo- and mixed-valence cis-diammineplatinum dimers and tetramers, HT-[Pt(2.0+)2(NH3)4(μ-C4H6NO)2](ClO4)2 (2), HH-[Pt(2.25+)2(NH3)4(μ-C4H6NO)2]2(ClO4)5 (4), HH-[Pt(2.25+)2(NH3)4(μ-C4H6NO)2]2(PF6)3(NO3)2 (5), {HH-[Pt(2.25+)2(NH3)4(μ-C4H6NO)2]2}{HH-[Pt(2.5+)2(NH3)4(μ-C4H6NO)2(NO3)]2}(PF6)2(NO3)7·6H2O (7), HH-[Pt(2.5+)4(NH3)8(μ-C4H6NO)4(Cl)](ClO4)3Cl2 (9), HH-[Pt(3.0+)2(NH3)4(μ-C4H6NO)2(Cl)2](NO3)2 (11), HH-[Pt(3.0+)2(NH3)4(μ-C4H6NO)2(Cl)(NO3)](NO3)2·H2O (12), and HT-[(H2O)(H3N)2Pt(3.0+)(μ-C4H6NO)2Pt(3.0+)(NH3)(μ-OH)]2(NO3)6·4H2O (14), have been isolated and characterized by X-ray diffraction, where HH and HT correspond to the head-to-head and head-to-tail isomers, respectively. The first spontaneous resolution has been observed for the chiral HT-Pt(2.0+)2 molecules (2). 7 has turned out to be the first 1:1 “stoichiometric” mixture of blue and tan (Pt(2.25+)4 and Pt(2.5+)4). The structural evidence supporting the axial coordination behaviors of the Pt(2.5+)4 tetramer has been obtained (7 and 9). A very unique quasi-one-dimensional halide-bridged system having a chain definition of [Pt(2.5+)4−Cl···]∞ has been characterized (9). The HT-Pt(3.0+)2 dimer has been found to release an NH3 group in aqueous media to form a dimer of dimers linked by μ-OH bridges (14). Relationships between the structural parameters and the average Pt oxidation state have been examined in detail to better understand the structure-transformation properties of the platinum-blue family. Remarkable structural differences observed between the pentacyclic α-pyrrolidinonate and the hexacyclic α-pyridonate systems are rationally interpreted in terms of differences in both the N−C−O bite angle and the Pt−N−C angle around the bridging geometry. In addition, spectrophotometric studies reveal that an outer-sphere electron-transfer process between two Pt(2.25+)4 molecules takes place to afford a Pt(2.0+)4 and a Pt(2.5+)4 molecule. General consideration for the solution properties of this family is also described. The synthesis of an α-pyridonate Pt(2.5+)4 complex is also reported.

A series of tetragold(I) complexes supported by tetraphosphine ligands, meso- and rac-bis[(diphenylphosphinomethyl)phenylphosphino]methane (meso- and rac-dpmppm) were synthesized and characterized to show that the tetranuclear Au(I) alignment varies depending on syn- and anti-arrangements of the two dpmppm ligands with respect to the metal chain. The structures of syn-[Au4 (meso-dpmppm)2X]X'3 (X = Cl; X' = Cl (4 a), PF6 (4 b), BF4 (4 c)) and syn-[Au4 (meso-dpmppm)2]X4 (X = PF6 (4 d), BF4 (4 e), TfO (4 f); TfO = triflate) involved a bent tetragold(I) core with a counter anion X incorporated into the bent pocket. Complexes anti-[Au4 (meso-dpmppm)2]X4 (X = PF6 (5 d), BF4 (5 e), TfO (5 f)) contain a linearly ordered Au4 string and complexes syn-[Au4 (rac-dpmppm)2X2]X'2 (X = Cl, X' = Cl (6 a), PF6 (6 b), BF4 (6 c)) and syn-[Au4 (rac-dpmppm)2]X4 (X = PF6 (6 d), BF4 (6 e), TfO (6 f)) consist of a zigzag tetragold(I) chain supported by the two syn-arranged rac-dpmppm ligands. Complexes 4 d-f, 5 d-f, and 6 d-f with non-coordinative large anions are strongly luminescent in the solid state (λmax = 475-515 nm, Φ = 0.67-0.85) and in acetonitrile (λmax = 491-520 nm, Φ = 0.33-0.97); the emission was assigned to phosphorescence from (3) [dσ*σ*σ* pσσσ] excited state of the Au4 centers on the basis of DFT calculations as well as the long lifetime (a few μs). The emission energy is predominantly determined by the HOMO and LUMO characters of the Au4 centers, which depend on the bent (4), linear (5), and zigzag (6) alignments. The strong emissions in acetonitrile were quenched by chloride anions through simultaneous dynamic and static quenching processes, in which static binding of chloride ions to the Au4 excited species should be the most effective. The present study demonstrates that the structures of linear tetranuclear gold(I) chains can be modified by utilizing the stereoisomeric tetraphosphines, meso- and rac-dpmppm, which may lead to fine tuning of the strongly luminescent properties intrinsic to the Au(I) 4 cluster centers.

With the aim of developing new 1D platinum chain solids having infinite Pt-Pt bonds, several carboxylate-bridged cis-diammineplatinum dimers have been prepared and structurally characterized. For a dimer doubly bridged with acetates, five different salts [Pt 2 (NH 3 ) 4 (µ-CH 3 CO 2 ) 2 ]X 2 ‚nH 2 O (X 2 , n ) (ClO 4 ) 2 , 2, 1; (NO 3 ) 2 , 1, 2; (BF 4 ) 2 , 4, 3; (PF 6 ) 2 , 2, 4; (SiF 6 ), 4, 5) have been prepared. The crystal structure of 5 has revealed that an infinite dimer chain [Pt 2 (NH 3 ) 4 (µ-CH 3 CO 2 ) 2 ] n 2n+ can be given as a result of hydrogen bond formation between the ammines and the oxygen atoms of acetates, demonstrating our prediction that the N 2 O 2 coordination sphere may serve as a hydrogen-bonding moiety to assist formation of an infinite dimer chain. An asymmetric dimer bridged by both acetate and hydroxide ligands, [Pt 2 (NH 3 ) 4 (µ-CH 3 CO 2 )(µ-OH)](SiF 6 ) (6), has also been isolated as a byproduct of 5, and a similar 1D framework, [Pt 2 (NH 3 ) 4 (µ-CH 3 CO 2 )(µ-OH)] n 2n+ , has been characterized by X-ray diffraction. In addition, some glycolate-bridged analogues of similar frameworks have been synthesized and characterized: [Pt 2 (NH 3 ) 4 (µ-CH 2 (OH)CO 2 ) 2 ](SiF 6 )‚4H 2 O (7), [Pt 2 (NH 3 ) 4 (µ-CH 2 -(OH)CO 2 ) 2 ](ClO 4 ) 2 ‚H 2 O (8), and [Pt 2 (NH 3 ) 4 (µ-CH 2 (OH)CO 2 )(µ-OH)](NO 3

Redox behavior of [UO2(gha)DMSO](-)/UO2(gha)DMSO couple (gha = glyoxal bis(2-hydroxanil)ate, DMSO = dimethyl sulfoxide) in DMSO solution was investigated by cyclic voltammetry and UV-vis-NIR spectroelectrochemical technique, as well as density functional theory (DFT) calculations. [UO2(gha)DMSO](-) was found to be formed via one-electron reduction of UO2(gha)DMSO without any successive reactions. The observed absorption spectrum of [UO2(gha)DMSO](-), however, has clearly different characteristics from those of uranyl(V) complexes reported so far. Detailed analysis of molecular orbitals and spin density of the redox couple showed that the gha(2-) ligand in UO2(gha)DMSO is reduced to gha(•3-) to give [UO2(gha)DMSO](-) and the formal oxidation state of U remains unchanged from +6. In contrast, the additional DFT calculations confirmed that the redox reaction certainly occurs at the U center in other uranyl(V/VI) redox couples we found previously. The noninnocence of the Schiff base ligand in the [UO2(gha)DMSO](-)/UO2(gha)DMSO redox couple is due to the lower energy level of LUMO in this ligand relative to those of U 5f orbitals. This is the first example of the noninnocent ligand system in the coordination chemistry of uranyl(VI).