Search

Radiation dosimeters that measure ionizing radiations over a broad range and allow for direct readout are desirable. Here, the authors present a dual-mode photochromic thorium-based metal-organic nanocluster that enables direct visible colorimetric dosimetry of UV, β-ray, and γ-ray radiation.

Versatile graphdiyne (GDY) substrate has been modified by numerous transition metals and resulting composites showed excellent photo/electro-catalytic performance. However, GDY materials modified by actinides that are stockpiled waste product due to large-scale use in nuclear industry, are particularly scarce and remains great challenge. To deeply understand the structural properties, GDY complexating actinyl (AnmO2)n+ (An = U, Np, Pu; m = VI, V) species with its atomistic pore was investigated by relativistic density functional theory (DFT). The GDY pore was found suitable to hold actinyl species, by forming organometallic AnC dative bonds. This chemical coupling interaction was further confirmed by quantum theory of atoms-in-molecule and electronic structure calculations. The GDY-uranyl(V), for instance, shows a π(UC) bonding HOMO, which is anticipated to improve electron transfer between ligand and metal. Orbital structures and compositions of complexes suggest their implication towards catalysis, which were further corroborated by calculations on redox potentials of GDY-actinyl complexes. Hence, our results show the potential applications of GDY complexating actinyl species towards novel catalytic surfaces. Keywords: Graphdiyne-actinyl, Electronic structures and bonding, Redox properties, Relativistic DFT calculations

Transition metal oxides (TMOs) and actinide ones (AnOs) have been widely applied in catalytic reactions due to their excellent physicochemical properties. However, the reaction pathway and mechanism, especially involving TM–An heterometallic centers, remain underexplored. In this respect, relativistic density functional theory (DFT) was used to examine uranium-doped zinc, copper, and nickel oxides for their catalytic activity toward the conversion of furfural to furfuryl alcohol. A comparison was made with their undoped TMOs. It was found that the three TMOs were capable of catalyzing the reaction, where the free energies of adsorption, hydrogenation, and desorption fell between −33.93 and 45.00 kJ/mol. The uranium doping extremely strengthened the adsorption of CuO-U and NiO-U toward furfural, making hydrogenation or desorption much harder. Intriguingly, ZnO-U showed the best catalytic performance among all six catalyst candidates, as its three reaction energies were very small (−10.54–8.12 kJ/mol). The reaction process and mechanism were further addressed in terms of the geometrical, bonding, charge, and electronic properties.

Well-crystallized and hexagonal wurtzite ZnO was synthesized with nanocellulose using a facile hydrothermal method. Many highly active (001) facets were retained in the obtained ZnO nanocrystals, presumably due to interaction between the polar facet of ZnO and the nanocellulose. Given its effective surface area, the synthesized ZnO exhibited good photocatalytic activity of degrading methylene blue. Its degradation efficiency reached 94.4% within 30 min (UV irradiation power of 6 W), which was 34% higher than that of Degussa TiO2 P25. The ZnO photocatalyst also exhibited excellent reusability, confirmed by no obvious abatement after its being re-used for 8 cycles. These ZnO nanomaterials were synthesized using renewable nanocellulose derived from cotton. This environmentally friendly and cost-effective approach is anticipated to be applied in the future synthesis of small-sized ZnO photocatalysts.

The exceptional ability of the Ru(sub 2)-(DMBA)(sub 4) unit in mediating electron mobility between ferrocenium and ferrocene reporter groups by voltammetric and spectroelectrochemical studies of the trans-(FcC (sub 2n))Ru(sub 2)(Y-DMBA)(sub 4) (C(sub 2m) Fc) series is demonstrated. The results obtained of charge transfer across carbon-rich bridges provide the validation of the proposal to realize molecular wires based on Ru(sub 2)-alkynyl oligomers.

Electronic structures and spectroscopic properties of a series of nitrido-osmium (VI) complex ions with acetylide ligands, [OsN(C=CR)4]- (R==H, (1), CH3 (2), and Ph (3)) were investigated theoretically. The structures of the complexes were fully optimized at the B3LYP and CIS level for the ground states and excited states, respectively. The calculated bond lengths of Os=N (1.639 Å in 1, 1.642 Å in 2, and 1.643 Å in 3) and Os–C (2.040 Å in 1, 2.043 Å in 2, and 2.042 Å in 3) in ground state agree well with the experimental results. The bond length of Os=N bond is lengthened by ca. 0.13 Å in the A 3B2 excited state compared to the 1A1 ground state, which is consistent with the lower vibration frequency of ν(Os–N) (∼780 cm-1) in the excited state than that (∼1175 cm-1) in the ground state. Among the calculated dipole-allowed absorptions at λ>250 nm, the intense absorption at 261 nm for 1, 266 nm for 2, and 300 nm for 3 were attributed to the 1[π(C=C)]→1[π*(N=Os)+π*(C=C)], 1[π(C=C)]→1[π*(N=Os)+π*(C=C)], and 1[π(C=CPh)]→1[π*(N=Os)+π*(C=CPh)], respectively. The lowest energy absorption at λmax=393 nm for 1, 400 nm for 2, and 400 nm for 3 were assigned as 1[dxy(Os)+π(C=C)]→1[π*(N=Os)+π*(C=C)], 1[dxy(Os)+π(C=C)]→1[π*(N=Os)+π*(C=C)], and 1[dxy(Os)+π(C=CPh)]→1[π*(N=Os)+π*(C=CPh)], respectively. The calculated phosphorescence emission at λmax=581 nm for 1, 588 nm for 2, and 609 nm for 3 were originated from 3[(π*(N=Os)+π*(C=C))1(dxy(Os)+π(C=C))1], 3[(π*(N=Os)+π*(C=C))1(dxy(Os)+π(C=C))1], and 3[(π*(N=Os)+π*(C=CPh))1(dxy(Os)+π(C=CPh))1] excited state, respectively. [ABSTRACT FROM AUTHOR]

The ground- and excited-state structures were fully optimized for a series of neutral binuclear Au(I) thiolates, [Au[sub 2](dpm)(SCH[sub 2]S)] (1) (dpm=bis(diphosphino)methane), trans-[Au[sub 2](PH[sub 2]CH[sub 2]S)[sub 2]] (2), and trans-[Au[sub 2](SHCH[sub 2]S)[sub 2]] (3), by using the MP2 and CIS methods, respectively. The calculated Au[sup I]–Au[sup I] distances of about 3.0 Å in the ground state of the complexes are indicative of aurophilic attraction between the two Au(I) atoms, while in their excited states the separations are greatly shortened (about 2.7–2.9 Å). The promotion of Au d electron or S p electron into the bonding s[sub σ] and/or p[sub σ] lowest unoccupied molecular orbital of Au[sup I]–Au[sup I] results in such reinforcement of aurophilicity in the excited state. In the CIS calculations of the three Au(I) thiolates, we obtained the lowest-energy phosphorescent emission in the solid state for each of the complexes. The 462 nm emission of 1 was assigned as Au→S charge transfer (MLCT) transition. But for 3, the charge transfer localized on the Au centers, [sup 3]A[sub u](s[sub σ])→[sup 1]A[sub u](d[sub σ[sup *]]) (metal-centered charge transfer, MCCT), plays a main role in the 413 nm emission. Both the MCCT and MLCT transitions are important in the 323 nm emission of 2. The results indicated that Au[sup I]–Au[sup I] aurophilicity clearly influences luminescent properties of these complexes. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

A series of ruthenium(II) complexes, [[Ru([H.sub.m]tcterpy)[(NCS).sub.3]].sup.n-] (m = 0, 1, 2, and 3; n = 4, 3, 2, and 1), are examined to explore their electronic structures and spectroscopic properties. The results have provided a direct insight into the origins of the transitions and their possible role in dye-sensitized solar cell injection dynamics, as well as the design of new and more efficient solar cells sensitizers.

The MP2 method is used to explore the structures of trans-[[M.sub.2][(CN).sub.4](P[H.sub.2]C[H.sub.2]P[H.sub.2]).sub.2]], trans-[[P[t.sub.2][X.sub.4](P[H.sub.2]C[H.sub.2]-P[H.sub.2).sub.2]] and trans-[[M[(CN).sub.2][(P[H.sub.3].sub.2]] in the ground state. It is predicted that Pt produces the lowest-energy d-p emission while Pd, Ni, Cl, and Br favor the d-d emissions.

The structures of [Pt2[(pop).sub.4)].sup.4-], [Pt2[(pcp).sub 4].sup.4-],and related species [Pt2[(pop).sub.4)X2].sup.4-] and [Pt2[(pop).sub.4)].sup.2-] in the ground states (pop = P2O5[H2.sup.2-] and pcp =P2O4C[H4.sup.2-]), and X = I, Br, and CL) were optimized employing the second-order Moller-Plesset perturbation method. The calculated aqueous absorption spectra at the time-dependent density functional theory (TD-DFT) level are found to agree with experimental observations.

Electronic structures and spectroscopic properties of [Pt(trpy)C triple bond CR](super +), CH2OH, and C6H5 are studied by ab initio and DFT methods. The calculations indicate that, for [Pt(trpy)C triple bond CR](super +), CH2OH, and C6H5, the variation of the substituents on the acetylide ligand slightly changes their structures in ground and excited states but leads to a sizable difference in the electronic structures.

The research conducted to investigate the electronic structures and spectroscopic properties of the binuclear head-to-tail [Au2(PH2CH2SH2](super 2+) complex, by ab initio calculations, is discussed.

Abstract Background We aimed to investigate the functions and underlying mechanism of lncRNA SNHG1 in bone differentiation and angiogenesis in the development of osteoporosis. Methods The differential gene or proteins expressions were measured by qPCR or western blot assays, respectively. The targeted relationships among molecular were confirmed through luciferase reporter, RIP and ChIP assays, respectively. Alkaline phosphatase (ALP), alizarin red S (ARS) and TRAP staining were performed to measure the osteoblast/osteoclast differentiation of BMSCs. The viability, migration and angiogenesis in BM-EPCs were validated by CCK-8, clone formation, transwell and tube formation assays, respectively. Western blot and immunofluorescence detected the cytosolic/nuclear localization of β-catenin. Ovariectomized (OVX) mice were established to confirm the findings in vitro. Results SNHG1 was enhanced and miR-181c-5p was decreased in serum and femoral tissue from OVX mice. SNHG1 directly inhibited miR-181c-5p to activate Wnt3a/β-catenin signaling by upregulating SFRP1. In addition, knockdown of SNHG1 promoted the osteogenic differentiation of BMSCs by increasing miR-181c-5p. In contrast, SNHG1 overexpression advanced the osteoclast differentiation of BMSCs and inhibited the angiogenesis of BM-EPCs, whereas these effects were all reversed by miR-181c-5p overexpression. In vivo experiments indicated that SNHG1 silencing alleviated osteoporosis through stimulating osteoblastogenesis and inhibiting osteoclastogenesis by modulating miR-181c-5p. Importantly, SNHG1 could be induced by SP1 in BMSCs. Conclusions Collectively, SP1-induced SNHG1 modulated SFRP1/Wnt/β-catenin signaling pathway via sponging miR-181c-5p, thereby inhibiting osteoblast differentiation and angiogenesis while promoting osteoclast formation. Further, SNHG1 silence might provide a potential treatment for osteoporosis. Graphic abstract

Dimeric complexes (RuIIPz)2 have been investigated using density functional theory (DFT), where Pz is a porphyrazine ligand that features a 16-atom, 18-π-electron cyclic polyene aromatic skeleton. Structural optimizations in various configurations and spin states indicate that (RuPz)2 favours a Pz-Pz staggered conformer over an eclipsed one; the paramagnetic triplet state with the staggered configuration is found as the global ground state. This agrees with experimental magnetic results of (RuOEPor)2 (OEPor=octaethylporphyrin) and (RuPc)2 (Pc=phthalocyanine). The Ru-Ru bond length was optimized to be 2.38Å, close to the experimental bond length of 2.40-2.41Å. The Ru2 doubly bonded nature has been evidenced by the Ru-Ru stretching vibrational frequency of 202cm-1, bond energy of 30.7 kcal mol-1, and electronic arrangement of σ²π4(nonbonding-δ)4(π*)². Further confirmation was obtained from high-level wave function theory calculations (complete active space self-consistent field and n-electron valence state second-order perturbation theory). Associated with the solvation of the explicit pyridine accounting for the first coordination sphere and the implicit continuum model for the long-range interaction, the electronic spectra of tetrapyrrolic ruthenium complex were calculated at the time-dependent DFT level. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to evaluate the clinical results of T-plate fixation and anterior sternoclavicular ligament repair in proximal clavicle fractures. Methods: Between August 2013 and August 2016, a total 12 patients (10 men and 2 women; mean age: 44.1 ± 9.1 years (range, 25–59 years)) with unstable proximal clavicle fractures (Throckmorton, type D) were treated with T-type plate fixation, bridging the sternoclavicular joint, and anterior sternoclavicular ligament repair. Average operative time, associated injuries, postoperative complications, postoperative fracture healing time and follow-up time were recorded. The outcomes were evaluated with radiographic assessment, visual analog scale (VAS) pain score and Rockwood SCJ scoring system. All the patients were evaluated on postoperative 3rd, 6th, and 12th months. Results: The average surgery time was 78.0 ± 8.47 minutes while fracture healing time was 4.51 ± 0.95 months. According to Rockwood SCJ scoring system, 9 cases (75%) were in excellent, 2 cases (16.7%) in good and 1 case (8.3%) in fair condition at 12 months follow-up. The average Rockwood SCJ score was 7.7 ± 0.75 preoperatively, 12.7 ± 0.86 by 3 months, 13.0 ± 0.73 by 6 months and 13.3 ± 0.49 by 12 months. The VAS pain score was 7.9 ± 1.15 (preoperative score), 3.4 ± 1.52 (3 months follow-up), 3.0 ± 1.32 (6 months follow-up) and 2.1 ± 1.07 (12 months follow-up). The VAS and Rockwood SCJ scores were significantly improved postoperatively (p

Abstract Background Steroids such as glucocorticoid have been widely used for their excellent anti-inflammatory, anti-immune, and anti-shock properties. However, the long-term use in high doses has been found to cause necrosis of femoral head and other serious adverse reactions. Thus, it is of great importance to safely use these medications on patients without inducing bone necrosis. Methods In this preclinical study, we examined the effects of erythropoietin (EPO) to attenuate the induction of steroid-induced femoral bone necrosis using rats to build up the in-vivo models. Rats were randomly divided into three groups: negative control group (group A), disease group (group B), and EPO group (group C). 20 mg/kg methylprednisolone was administrated into group B and group C for 6 weeks with two intramuscular injections per week per rat. Group C was further given daily intraperitoneal injections of rHuEPO during this period. Group A received only injection of saline at the same schedule. 12 weeks after the initial drug administration, the rats’ femoral tissues were harvested for HE staining, immunohistochemistry studies for PECAM-1(also CD31) expression and Western Blotting for VEGF expression. Results Histology studies showed that compared with the disease group, EPO group had significant improvement and bone morphology being much closer to the negative control group. Immunohistochemical studies revealed that EPO group had statistically much more expression of PECAM-1 than the other groups did. Western Blot demonstrated that the EPO group had significantly higher VEGF expression than the disease group. Conclusion Results suggested that simultaneous injection of EPO could partially prevent steroid-induced ANFH.

Iridium(III) complexes with N-heterocyclic (NHC) ligands including fac-Ir(pmb)3 (1), mer-Ir(pmb)3 (2), (pmb)2Ir(acac) (3), mer-Ir(pypi)3 (4), and fac-Ir(pypi)3 (5) [pmb = 1-phenyl-3H-benzimidazolin-2-ylidene, acac = acetoylacetonate, pypi = 1-phenyl-5H-benzimidazolin-2-ylidene; fac = facial, mer = meridional] were investigated theoretically. The geometry structures of 1–5 in the ground and excited state were optimized with restricted and unrestricted DFT (density functional theory) methods, respectively (LANL2DZ for Ir atom and 6-31G for other atoms). The HOMOs (highest occupied molecular orbitals) of 1–3 are composed of d(Ir) and π(phenyl), while those of 4 and 5 are contributed by d(Ir) and π(carbene). The LUMOs (lowest unoccupied molecular orbitals) of 1, 2, 4, and 5 are localized on carbene, but that of 3 is localized on acac. The calculated lowest-lying absorptions with TD-DFT method based on Perdew-Burke-Erzenrhof (PBE) functional of 1 (310 nm), 2 (332 nm), and 3 (347 nm) have MLcarbeneCT/ILphenyl→carbeneCT (MLCT = metal-to-ligand charge transfer; ILCT = intraligand charge transfer) transition characters, whereas those of 4 (385 nm) and 5 (389 nm) are assigned to MLcarbeneCT/ILcarbene→carbeneCT transitions. The phosphorescences calculated by TD-DFT method with PBE0 functional of 1 (386 nm) and 2 (388 nm) originate from 3MLcarbeneCT/3ILphenyl→carbeneCT excited states, but those of 4 (575 nm) and 5 (578 nm) come from 3MLcarbeneCT/3ILcarbene→carbeneCT excited states. The calculated results showed that the carbene and phenyl groups act as two independent chromophores in transition processes. Compared with 1 and 2, the absorptions of 4 and 5 are red-shifted by increasing the effective π-conjugation groups near the Ccarbene atom. We predicated that (pmb)2Ir(acac) is nonemissive, because the LUMO of 3 is contributed by the nonemissive acac ligand. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2010 [ABSTRACT FROM AUTHOR]

To understand their photocatalytic activity and application in luminescent materials, a series of gold and rhodium phosphine complexes (mononuclear [Au[supI](PH[sub3])[sub2]][sup+] (1) and [Rh[supI](CNH)[sub2](PH[sub3])[sub2]][sup+] (2); homobinuclear [Au[supI][sub2](PH[sub2]CH[sub2]PH[sub2])[sub2]][sup2+] (6), and [Au[supII]Rh[supII](CNH)[sub2](PH[sub2]NHPH[sub2])[sub2]][sup2+] (7); and oxidized derivatives [A[supII]Rh[supII](CNH)[sub2](PH[sub2]CH[sub2]PH[sub2])[sub2]][sup4+] (8), [Au[supII]Rh[supII](CNH)[sub2](PH[sub2]NHPH[sub2])[sub2]Cl[sub3]][sup+] (9), and [Au[supII]Rh[supII](CNH)[sub2](PH[sub2]NHPH[sub2])[sub2]][sup4+] (10)) were investigated using ab initio methods and density functional theory. With the use of the MP2 method, the M-M' distances in 3-7 were estimated to be in the range of 2.76-3.02 Å, implying the existence of weak metal-metal interaction. This is further evident in the stretching frequencies and bond orders of M-M'. The two-electron oxidation from 5-7 to their respective partners 8-10 was shown to mainly occur in the gold-rhodium centers. Experimental absorption spectra were well reproduced by our time-dependent density functional theory calculations. The metal-metal interaction results in a large shift of d[subz[sup2]] → p[subz] transition absorptions in binuclear complexes relative to mononuclear analogues and concomitantly produces a low-lying excited state that is responsible for increasing visible-light photocatalytic activities. Upon excitation, the metal-centered transition and the metal-to-metal charge transfer strengthen the metal-metal interaction in triplet excited states for 3-6, while the promotion of electrons into the σ*(d[subz[sup2]]) orbital weakens the interaction in 9. [ABSTRACT FROM AUTHOR]

Electronic structures, absorptions and emissions of a series of (ppy)2Ir(acac) derivatives (ppy = 2- phenylpyridine; acac = acetoylacetonate) with fluoro substituent on ppy ligands were investigated theoretically. The ground and excited states geometries were fully optimized at B3LYP/LANL2DZ and CIS/LANL2DZ level, respectively. The HOMO is composed of d(Ir) and π(C∧N), while the LUMO is localized on C∧N ligand. The absorptions and emissions in CH2Cl2 media were calculated under the TD–DFT level with PCM model. The lowest-lying absorption of these complexes is dominantly attributed to metal-to-ligand and intraligand charge transfer (MLCT/ILCT) transitions and the emission of them originates from 3MLCT/3ILCT excited states. The absorption and emission of these complexes are blue-shifted by increasing the number of fluoro on phenyl, but the spectra are red-shifted by adding fluoro on pyridyl. While a single fluoro of different substituted site on phenyl results in different extent blue-shift to the spectra. [ABSTRACT FROM AUTHOR]

A comprehensive calculations were carried out to get a deep insight into the ground- and excited-state electronic structures and the spectroscopic properties for a series of [Pt(4-X–trpy)C≡CC6H4R]+ complexes (trpy = 2,2′,6′,2″-terpyridine; X = H, R = NO2 (1), Cl (2), C6H5 (3) and CH3 (4); R = Cl, X =CH3 (5) and C6H5 (6)). MP2 (second-order Møller–Plesset perturbation) and CIS (single-excitation configuration interaction) methods were employed to optimize the structures of 1–6 in the ground and excited states, respectively. The investigation showed that substituted phenylacetylide and trpy ligands only give rise to a small variation in geometrical structures but lead to a sizable difference in the electronic structures for 1–6 in the ground and excited states. The introduction of electron-rich groups into the phenylacetylide and/or terpyridyl ligands produces two different low-lying absorptions for 1 and 2–6, i.e., Pt(5d) → π∗(trpy) metal-to-ligand charge transfer (MLCT) mixed with π →π∗≡(CCPh) intraligand charge transfer (ILCT) for 1 and Pt(5d)/π(C≡CPh) → π∗(trpy) charge transfer (MLCT and LLCT) for 2–6. Remarkable electronic resonance on the whole Pt–CCPh–NO2 moiety for 1 may be responsible for the difference. Solvatochromism calculation revealed that only LLCT/MLCT transitions showed the solvent dependence, consistent with the experimental observations. [Copyright &y& Elsevier]

The binuclear gold phosphorus ylide complexes [Au I2(CH 2PH 2CH 2) 2] ( 1), [Au II2X 2(CH 2PH 2CH 2) 2] (X = Cl ( 2a), Br ( 2b), I ( 2c)), [Au III2X 4(CH 2PH 2CH 2) 2] (X = Cl ( 3a), Br ( 3b)), and [Au IAu IIIX 2(CH 2PH 2CH 2) 2] (X = Cl ( 4a), Br ( 4b)) were explored using density functional theory and ab initio methods. The use of methods, basis sets, and substituent effects confirmed our calculations. The analyses on their electronic structures reveal that two- and four-electron oxidation from 1to 2− 4mainly occurs at the gold centers, resulting in their different coordination geometry features and metal−metal interactions as well as spectroscopic properties. Bond-order and frequency calculations provided the evidence for the weak Au−Au bonding interaction in 1, 3, and 4and an approximate Au−Au single bond in 2. Unrestricted MP2 calculations showed that the triplet excited-state structures of 1, 2a, and 3aare minimum points on the potential energy surface. Upon excitation, the Au−Au distances of 1and 3ashorten while that of 2aincreases. This is closely correlated with the promotion of electrons into the bonding or antibonding orbitals of the gold centers. [ABSTRACT FROM AUTHOR]

The structures of trans-M2(CN)4(PH2CH2PH2)2(M Pt (1), Pd (2), and Ni (3)), trans-Pt2X4(PH2CH2PH2)2(X Cl (4) and Br (5)), and trans-M(CN)2(PH3)2(M Pt (6), Pd (7), and Ni (8)) in the ground state were optimized using the MP2 method. Frequency calculations reveal that the weak metal−metal interaction is essentially attractive for 1, 2, 4, and 5but not for 3. The TD-DFT calculations associated with the polarized continuum model (PCM) were performed to predict absorption spectra in CH2Cl2solution. Experimental spectra are well reproduced by our results. With respect to analogous mononuclear d8complexes (6−8), a large red shift of the absorption wavelength was calculated for the binuclear d8complexes (1−3). Relative to 1with unsaturated CN-donors, introduction of saturated halogen donors into 4and 5changes their electronic structures, especially the HOMO and LUMO. The TD-DFT and subsequent unrestricted MP2 calculations predict that 1produces the lowest-energy d → p emission while 2−5favor the d → d emissions, agreeing with experimental observations. [ABSTRACT FROM AUTHOR]

The structures of [Pt2(pop)4]4-, [Pt2(pcp)4]4-, and related species [Pt2(pop)4X2]4- and [Pt2(pop)4]2- in the ground states (pop = P2O5H22-, pcp = P2O4CH42- and X = I, Br, and Cl) were optimized using the second-order Møller-Plesset perturbation (MP2) method. It is shown that the Pt-Pt distances decrease in going from [Pt2(pop)4]4- to [Pt2(pop)4X2]4- to [Pt2(pop)4]2-. This is supported by the analyses of their electronic structures. The calculated aqueous absorption spectra at the time-dependent density functional theory (TD-DFT) level agree with experimental observations. The unrestricted MP2 method was employed to optimize the structures of (Pt2(pop)4]4- and [Pt2(pcp)4]4 in the lowest-energy triplet excited states. The Pt-Pt contraction trend is well reproduced in these calculations. For [Pt2(pop)4]4-, the Pt-Pt distance decreases from 2.905 Å in the ground state to 2.747 Å in the excited state, which is comparable to experimental values of 2.91-2.92 Å and 2.64-2.71 Å, respectively. On the basis of the excited-state structures of such complexes, TD-DFT predicts the solution emissions at 480 and 496 nm, which is closer to the experimental values of 512 and 510 nm emissions, respectively. [ABSTRACT FROM AUTHOR]

Based on their MP2 optimized structures in the ground states, we obtained solution absorption spectra for trans-[PtII(C≡CR)2(PH3)2] (R = H (1) and Ph (2)) and trans-[PtII(C≡CH)2(PH2CH2PH2)]2 (3) under the time-dependent density functional theory calculations. These absorptions agree with experimental observations. The unrestricted MP2 optimization performed for 3 in the lowest-energy triplet excited state shows that upon excitation the PtPt distance shortens about 0.347 Å with respect to the 3.188 Å one in the ground state. The UMP2 calculations estimated that its 3[σ*(dz2)σ(pz)] excited state produces the 531 nm emission, corresponding to the 580 nm one of trans-[PtII(C≡CPh)2(PPh2CH2PPh2)]2 in the solid state at 298 K. [Copyright &y& Elsevier]