scholarly journals Robin Jon Hawes Clark. 16 February 1935—6 December 2018

2020 ◽  
Vol 68 ◽  
pp. 103-129
Author(s):  
Alwyn G. Davies ◽  
Paul F. McMillan
Keyword(s):  
Raman Spectroscopy ◽  
Inorganic Compounds ◽  
Resonance Raman Spectroscopy ◽  
Linear Chain ◽  
Mixed Valence ◽  
Far Infrared ◽  
Vanadium Complexes ◽  
Coordination Numbers ◽  
Metal Metal ◽  
High Coordination

Robin Clark was a distinguished physical/inorganic chemist who made major discoveries in the coordination chemistry of the early transition metals, especially of titanium and vanadium complexes with high coordination numbers (notably seven and eight) and of the structures and physical properties of mixed valence, linear chain and metal–metal bonded compounds. He applied far-infrared spectroscopy to study metal–ligand vibrations systematically and established the technique for structure elucidation of transition metal and main group compounds. He also developed Raman and resonance Raman spectroscopy applied to inorganic compounds and highly coloured solids including mineral samples. That work led to his seminal applications of microbeam Raman spectroscopy for the identification of pigments and other constituents of artworks and historical artefacts, thereby developing a basis for testing their provenance and the identification of forgeries.

Electronic and Resonance Raman Spectra of the Linear Chain Mixed Valence Compound Pt(NH3)2(SCN)2I

1980 ◽  
Vol 35 (10) ◽  
pp. 1272-1273 ◽  
Author(s):  
Robin J. H. Clark ◽  
Mohamedally Kurmoo ◽  
K. D. Buse ◽  
H. J. Keller
Keyword(s):  
Raman Spectroscopy ◽  
Raman Spectra ◽  
Resonance Raman Spectroscopy ◽  
Linear Chain ◽  
Mixed Valence ◽  
Resonance Raman ◽  
Mixed Valence Compound ◽  
Resonance Raman Spectra

Abstract The partially oxidized cis-Pt(NH3)2(SCN)2I has been studied by resonance Raman spectroscopy. A progression in the symmetric I-PtIV-I vibration (v1 = 120.1 cm-1), reaching as far as 8 v1, has been observed. The compound Pt(NH3)2(SCN)2I could be identified as a mixed valence solid with neutral, linear PtII···I-PtIV chains.

Linear Chain Bis(α,β-dionedioximato)metal Compounds of the Nickel Triad: Solid State Design by Molecular Engineering

1977 ◽  
Vol 32 (5) ◽  
pp. 516-527 ◽  
Author(s):  
H. Endres ◽  
H. J. Keller ◽  
R. Lehmann ◽  
A. Poveda ◽  
H. H. Rupp ◽  
...  
Keyword(s):  
Solid State ◽  
Linear Chain ◽  
Mixed Valence ◽  
Structural Data ◽  
Molecular Engineering ◽  
Complex Molecules ◽  
Metal Compounds ◽  
Metal Interactions ◽  
Wide Range ◽  
Metal Metal

Chemical and structural data of numerous bis(α,β-dionedioximato)metal(II) compounds are summarized. All of them crystallize in columns but principally two different kinds of molecular arrangements occur in the solids. In one phase the molecular planes are inclined to the direction of the linear metal chains with an angle different from 90°. This allows only indirect interactions between the metal ions via the ligand. (“M—L—M” stacking.) The other modification consists of molecules with their planes perpendicular to the M—M-chains. This form allows direct metal-metal contacts (“M—M” modification). Depending on a few molecular parameters a “M—L—M” or a “M—M” stacking is obtained upon crystallization. Since for those compounds which could be isolated in both modifications the M—L—M form has the higher density it is concluded that only stronger M—M interactions stabilize the less dense M—M forms.A wide range of metal-metal separations with a lower limit of 3.15 Å in mixed valence systems are found in different “M—M” compounds. In any case the intrachain metal-metal distances are reduced considerably upon oxidation of the bivalent complex molecules. The influence of “electronic” and “sterical” parameters of the complex molecules on the intermolecular metal interactions and on the type of columns in the solid state is discussed.

Far-infrared and resonance raman spectroscopy and isotopic substitution studies of halogen-bridged platinum chain solids

1993 ◽  
Vol 56 (2-3) ◽  
pp. 3456-3460 ◽  
Author(s):  
S.P. Love ◽  
L.A. Worl ◽  
R.J. Donohoe ◽  
S.C. Huckett ◽  
S.R. Johnson ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Resonance Raman Spectroscopy ◽  
Resonance Raman ◽  
Far Infrared ◽  
Isotopic Substitution ◽  
Platinum Chain

Vibrational studies of, and model for, halogen-bridged linear-chain mixed-valence complexes

1985 ◽  
Vol 314 (1528) ◽  
pp. 131-144 ◽  
Keyword(s):  
Resonance Raman Spectroscopy ◽  
Linear Chain ◽  
Mixed Valence ◽  
Force Constants ◽  
One Dimensional ◽  
Moderate Resolution ◽  
Vibrational Studies ◽  
The One ◽  
Expected Increase ◽  
Chain Interaction

A number of complexes of the type [M II (LL) 2 ] [Pt IV (LL) 2 Cl 2 ] [ClO 4 ] 4 , where M = Ni, Pd or Pt and LL = 1,2-diaminoethane (en) or 1,2-diaminopropane (pn), as well as the monomers [Pt IV (LL) 2 Cl 2 ] Cl 2 and [M II (LL) 2 ] Cl 2 have been studied using Fourier transform infrared (f.t.i.r.) and resonance Raman spectroscopy. Under conditions of low tem perature and moderate resolution ( ca . 0.5 cm -1 ) it has proved possible to observe chlorine isotopic splitting in bands due to both the symmetric and the antisymmetric stretching modes of the linear Pt IV Cl 2 units in the chains. On the basis that the one-dimensional electronic properties of these chains are likely to be related to the in-chain Pt IV -Cl stretching force constants, a simple vibrational model is presented, which is able to reproduce the observed splitting patterns to well within experimental error. A comparative study of the Pt IV -Cl stretching force constants for the series of en complexes shows the trend: trans -[Pt IV (en) 2 Cl 2 ] Cl 2 (monomer) > Pd II - Pt IV > Ni II - Pt IV > Pt II −Pt lV . This trend is in line with that of the M II …Pt IV intervalence band maxima, namely Pd II - Pt IV (25000 cm -1 ) > Ni II - Pt IV (22200 cm -1 ) > Pt II - Pt IV (20800 cm -1 ), indicating an increase in M II … Cl chain interaction (and an expected increase in conductance) along the series.

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