%0 Journal Article %1 Bell.1992 %A Bell, Sharon E. %A Field, John S. %A Haines, Raymond J. %A Moscherosch, Michael %A Matheis, Walter %A Kaim, Wolfgang. %D 1992 %J Inorganic Chemistry %K TCNE TCNE;ESR TCNQ complex complex;ruthenium electrochem redox ruthenium %N 15 %P 3269--3276 %R 10.1021/ic00041a020 %T Novel and stable metal-metal-bonded diruthenium(I) complexes containing TCNX0/.bul.- in both the inner and the outer coordination sphere (TCNX = TCNE, TCNQ). A combined EPR/ENDOR-, UV/visible/near-IR-, and IR-spectroscopic and electrochemical investigation %V 31 %X Reaction of diphosphazane-bridged Ru2(m-CO)(CO)4m-(RO)2PN(Et)P(OR)22 (R = Me, CHMe2) with the electron acceptors TCNX (X = Q, E) affords Ru2(CO)5μ-(RO)2PN(Et)P(OR)22(η1-TCNX)(TCNX) contg. a TCNX radical anion in both the inner and outer coordination sphere of the cation. The contribution of the coordinated TCNX.bul.- to the EPR/ENDOR and UV/visible/near-IR spectra of these salts is partly obscured by that of the external, completely dissocd. D2h-sym. TCNX.bul.-, but the IR vibrational spectra and the cyclic voltammograms show the presence of both coordinated and noncoordinated species. Four distinct and reversible redn. waves appear in PhCN; 2 correspond to the TCNX0/- and TCNX-/2- couples of the external TCNX, while the other pair, shifted by $\sim$0.3 V to more pos. potentials because of rather weak Ru $\rightarrow$ TCNX p back-donation, are readily assigned to the corresponding redox couples of the coordinated TCNX. The external TCNQ.bul.- of the TCNQ salts is readily exchanged for diamagnetic BPh4- to give Ru2(CO)5μ-(RO)2PN(Et)P(OR)22(η1-TCNQ)(BPh4) enabling UV/visible/near-IR, IR, and EPR spectra of the coordinated TCNQ.bul.- to be recorded in CH2Cl2 without interference from the external TCNQ.bul.-; the IR and EPR data confirm the low symmetry of the h1- bound TCNQ.bul.-. With the aid of HMO/McLachlan perturbation calcns. and ENDOR measurements the 1st reproducible EPR spectra of a coordinated TCNQ.bul.- are reported; the 1H and 14N hyperfine coupling consts. used to simulate the EPR spectra fit the pattern calcd. for a TCNQ.bul.- bonded in the h1-mode to 1 metal center. Replacement of the external TCNE.bul.- in the TCNE salts by a diamagnetic anion could not be achieved, but since the external TCNE.bul.- is more easily oxidized than bound TCNE.bul.-, selective oxidn. of the former in situ to diamagnetic neutral TCNE could be accomplished, allowing EPR spectra of the coordinated TCNE.bul.- to be recorded in CH2Cl2 without interference from external TCNE.bul.-. Reproductions of the resolved EPR spectra showed that, like TCNQ.bul.-, TCNE.bul.- is bonded in the h1-mode to 1 metal center. In situ oxidn. of Ru2(CO)5μ-(RO)2PN(Et)P(OR)22(η1-TCNX)+ affords the completely oxidized dications contg. a neutral coordinated TCNX ligand. on SciFinder(R)

@article{Bell.1992, abstract = {Reaction of diphosphazane-bridged Ru2(\textgreek{m}-CO)(CO)4[\textgreek{m}-(RO)2PN(Et)P(OR)2]2 (R = Me, CHMe2) with the electron acceptors TCNX (X = Q, E) affords {Ru2(CO)5[μ-(RO)2PN(Et)P(OR)2]2(η1-TCNX)}(TCNX) contg. a TCNX radical anion in both the inner and outer coordination sphere of the cation. The contribution of the coordinated TCNX.bul.- to the EPR/ENDOR and UV/visible/near-IR spectra of these salts is partly obscured by that of the external, completely dissocd. D2h-sym. TCNX.bul.-, but the IR vibrational spectra and the cyclic voltammograms show the presence of both coordinated and noncoordinated species. Four distinct and reversible redn. waves appear in PhCN; 2 correspond to the TCNX0/- and TCNX-/2- couples of the external TCNX, while the other pair, shifted by $\sim$0.3 V to more pos. potentials because of rather weak Ru $\rightarrow$ TCNX \textgreek{p} back-donation, are readily assigned to the corresponding redox couples of the coordinated TCNX. The external TCNQ.bul.- of the TCNQ salts is readily exchanged for diamagnetic BPh4- to give {Ru2(CO)5[μ-(RO)2PN(Et)P(OR)2]2(η1-TCNQ)}(BPh4) enabling UV/visible/near-IR, IR, and EPR spectra of the coordinated TCNQ.bul.- to be recorded in CH2Cl2 without interference from the external TCNQ.bul.-; the IR and EPR data confirm the low symmetry of the \textgreek{h}1- bound TCNQ.bul.-. With the aid of HMO/McLachlan perturbation calcns. and ENDOR measurements the 1st reproducible EPR spectra of a coordinated TCNQ.bul.- are reported; the 1H and 14N hyperfine coupling consts. used to simulate the EPR spectra fit the pattern calcd. for a TCNQ.bul.- bonded in the \textgreek{h}1-mode to 1 metal center. Replacement of the external TCNE.bul.- in the TCNE salts by a diamagnetic anion could not be achieved, but since the external TCNE.bul.- is more easily oxidized than bound TCNE.bul.-, selective oxidn. of the former in situ to diamagnetic neutral TCNE could be accomplished, allowing EPR spectra of the coordinated TCNE.bul.- to be recorded in CH2Cl2 without interference from external TCNE.bul.-. Reproductions of the resolved EPR spectra showed that, like TCNQ.bul.-, TCNE.bul.- is bonded in the \textgreek{h}1-mode to 1 metal center. In situ oxidn. of {Ru2(CO)5[μ-(RO)2PN(Et)P(OR)2]2(η1-TCNX)}+ affords the completely oxidized dications contg. a neutral coordinated TCNX ligand. [on SciFinder(R)]}, added-at = {2022-06-15T11:26:56.000+0200}, author = {Bell, Sharon E. and Field, John S. and Haines, Raymond J. and Moscherosch, Michael and Matheis, Walter and Kaim, Wolfgang.}, biburl = {https://puma.ub.uni-stuttgart.de/bibtex/26840eae1b713311f9d58308f619a2d4e/huebleriac}, doi = {10.1021/ic00041a020}, interhash = {6a1f39fefc997ccd34c05fb2abd772fb}, intrahash = {6840eae1b713311f9d58308f619a2d4e}, issn = {0020-1669}, journal = {Inorganic Chemistry}, keywords = {TCNE TCNE;ESR TCNQ complex complex;ruthenium electrochem redox ruthenium}, number = 15, pages = {3269--3276}, timestamp = {2022-06-15T09:26:56.000+0200}, title = {Novel and stable metal-metal-bonded diruthenium(I) complexes containing TCNX0/.bul.- in both the inner and the outer coordination sphere (TCNX = TCNE, TCNQ). A combined EPR/ENDOR-, UV/visible/near-IR-, and IR-spectroscopic and electrochemical investigation}, volume = 31, year = 1992 }