Mixed-valence nickel(II)/platinum(IV) chain complexes. Electronic, infrared, Raman, and resonance Raman studies

Comparison of the electronic structures of chromate, halochromates, and chromyl halides by the X.alpha. method

“…Recently, the lower excited states of Cr042-, Cr03X-, and Cr02X2 with X = F and Cl have received renewed experimental interest with the observation of their previously elusive lowest lying spin-triplet states. [11][12][13][14][15][16][17] Prompted by these experimental results, the present theoretical study on this series of Cr(VI) complexes was undertaken to compare the electronic structure of the members of the series in a common calculational scheme. The Xa-scattered wave method, which has been reviewed by several authors,5•18-20 is employed.…”

Mixed-valence linear-chain complexes: X-ray structural characterization of a PdII/PdIVBr2 chain and of three mixed-metal chains, [NiPt(en)4Cl2]4+, [PdPt(pn)4Cl2]4+ and [NiPt(pn)4Cl2]4+, all as perchlorate salts

“…Complex (1) was prepared as described by Clark, Croud & Kurmoo (1983), complex (2) as described by Clark & Croud (1986), complex (3) as described by Clark & Croud (1985), and complex (4) as described by Clark et al (1988), in which papers the appropriate analyses are given.…”

“…(2) 1164 (2) 5833 (5) 5000 52 (1) O(i) 1611 (8) 4380 (20) 5000 110 (7) 0(2) 1574 (7) 7410 (20) 5000 101 (6) 0 (3) 752 (4) 5809 (12) 2828 (14) 73 ( (2) 416 (5) 2386 (14) 0 40 (3) C (1) 1451 (9) 689 (25) 910 (32) 43 ( oxidation states, p can be directly correlated with the magnitude of the band gap (Ee) and hence with the optical and electronic properties. However, if M" is changed, the mangitude of Ee in these anisotropic semiconductors changes and, in some cases, the optical properties as well (Clark et al, 1988;Clark & Croud, 1985, 1986, even though this has little effect on p. For example, for the complexes [M(en)2llM'(en)2Cl2l-(CIO4) 4, Ee varies from ca 1.5 eV [M = M'= Pd, via Raman-band excitation profiles (Clark et al, 1983)] to ca 2.2 eV [M=M' = Pt, via single-crystal polarized electronic spectra (Tanino & Kobayashi, 1983)], to ca 2.75 e V[M = Ni, M' = Pt, via electronic spectra obtained as Nujol mulls (Clark & Croud, 1986)], to ca 3.0 e V [M =Pd, M'= Pt via Raman-band excitation profiles (Clark & Croud, 1985)], yet the p and M H...M ~v distances of all these complexes are almost identical with one another. First, let us try to rationalize the effect of halide substitution in the pure palladium or platinum complexes.…”

“…Recent spectroscopic studies have pointed to the existence of analogous palladium mixed-valence complexes and also of mixed-metal complexes of the sort [M(LL) (Clark, Croud & Wills, 1988;Clark & Croud, 1985, 1986 (Beauchamp, Layek & Theophanides, 1982) whilst the structure of the corresponding bromide, our compound (1), was reported whilst our work was in progress (Martin, Keller & Muller, 1985). This paper is concerned with the characterization of three mixed-metal complexes, (3) and [Ni(pn)2][Pt(pn)2C12](CIO4) 4 (4).…”

Halogen-Bridged Mixed-Valence Linear-Chain Complexes: Molecular Orbital Model of Electron Localization

“…We will be concerned here with two families of compounds with en and tn as equatorial bidentate ligands, respectively. Metal-alternated mixed-valence complexes have also been reported in the literature, 5a,,− but they will not be studied here.…”