%0 Journal Article %1 Kaim.1987g %A Kaim, Wolfgang %A Kohlmann, Stephan. %D 1987 %J Inorganic Chemistry %K Group MO VIB azobipyridine bipyrimidine bischelant carbonyl;Group carbonyl;MO carbonyl;electronic carbonyl;energy electrochem electrochem;bipyrimidine electrochem;electrochem electrochem;pyridyltetrazine level pyridylpyrazine pyridyltetrazine;pyridylpyrazine transition %N 1 %P 68--77 %R 10.1021/ic00248a016 %T Four bridging bis chelate ligands with very low lying p* orbitals. MO perturbation calculations, electrochemistry, and spectroscopy of mononuclear and binuclear group 6 metal tetracarbonyl complexes %V 26 %X Coordination characteristics of the 4 bridging, p-delocalized bis chelate ligands 2,2'-bipyrimidine (bpym), 2,5-bis(2-pyridyl)pyrazine (bppz), 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine (bptz), and azo-2,2'-bipyridine (abpy) were evaluated with use of p MO perturbation calcns. and were studied exptl. by example of mononuclear and binuclear complexes with the fragments M(CO)4 (M = Cr, Mo, W). The substantial stabilization of the p* (LUMO) levels in the order bpym, bppz, bptz, abpy strongly facilitates redn. of the complexes and causes shifts of the intense metal-to-ligand charge-transfer (LMCT) absorption bands out into the near-IR region. Despite a notable activation barrier for the formation of binuclear abpy complexes with 6-coordinate metals, (abpy)Mo(CO)42 was prepd. and it exhibits most remarkable spectral properties such as an intense yet rather narrow and solvent-insensitive MLCT absorption band at 11,000 cm-1, another detectable absorption max. \textgreater30,000 cm-1, a redn. potential close to that of the ref. electrode, SCE, and closely spaced yet well-resolved CO stretching frequencies in the IR spectrum. All these spectral results can be correlated to p MO calcn. data, which strongly suggest the use of bptz and abpy for studies concerned with ligand-mediated electronic interactions between metal centers. A particular asset of binuclear abpy complexes is the unusually short metal-metal distance caused by their coordination-induced S-frame conformation. on SciFinder(R)

@article{Kaim.1987g, abstract = {Coordination characteristics of the 4 bridging, \textgreek{p}-delocalized bis chelate ligands 2,2'-bipyrimidine (bpym), 2,5-bis(2-pyridyl)pyrazine (bppz), 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine (bptz), and azo-2,2'-bipyridine (abpy) were evaluated with use of \textgreek{p} MO perturbation calcns. and were studied exptl. by example of mononuclear and binuclear complexes with the fragments M(CO)4 (M = Cr, Mo, W). The substantial stabilization of the \textgreek{p}* (LUMO) levels in the order bpym, bppz, bptz, abpy strongly facilitates redn. of the complexes and causes shifts of the intense metal-to-ligand charge-transfer (LMCT) absorption bands out into the near-IR region. Despite a notable activation barrier for the formation of binuclear abpy complexes with 6-coordinate metals, (abpy)[Mo(CO)4]2 was prepd. and it exhibits most remarkable spectral properties such as an intense yet rather narrow and solvent-insensitive MLCT absorption band at 11,000 cm-1, another detectable absorption max. {\textgreater}30,000 cm-1, a redn. potential close to that of the ref. electrode, SCE, and closely spaced yet well-resolved CO stretching frequencies in the IR spectrum. All these spectral results can be correlated to \textgreek{p} MO calcn. data, which strongly suggest the use of bptz and abpy for studies concerned with ligand-mediated electronic interactions between metal centers. A particular asset of binuclear abpy complexes is the unusually short metal-metal distance caused by their coordination-induced S-frame conformation. [on SciFinder(R)]}, added-at = {2022-06-15T11:26:56.000+0200}, author = {Kaim, Wolfgang and Kohlmann, Stephan.}, biburl = {https://puma.ub.uni-stuttgart.de/bibtex/232ee25b910134ec22e13a1b299291934/huebleriac}, doi = {10.1021/ic00248a016}, interhash = {6939cad18951d07991ceb8002a8240c6}, intrahash = {32ee25b910134ec22e13a1b299291934}, issn = {0020-1669}, journal = {Inorganic Chemistry}, keywords = {Group MO VIB azobipyridine bipyrimidine bischelant carbonyl;Group carbonyl;MO carbonyl;electronic carbonyl;energy electrochem electrochem;bipyrimidine electrochem;electrochem electrochem;pyridyltetrazine level pyridylpyrazine pyridyltetrazine;pyridylpyrazine transition}, number = 1, pages = {68--77}, timestamp = {2022-06-15T09:26:56.000+0200}, title = {Four bridging bis chelate ligands with very low lying \textgreek{p}* orbitals. MO perturbation calculations, electrochemistry, and spectroscopy of mononuclear and binuclear group 6 metal tetracarbonyl complexes}, volume = 26, year = 1987 }