Synthesis and characterization of trans-dicyano(1,4,8,11-tetraazacyclotetradecane) chromium(III) perchlorate [1]

Kane-Maguire, Noel A. P.; Bennett, Jonathan; Miller, P. K.

doi:10.1016/s0020-1693(00)81476-0

Cited by 32 publications

(20 citation statements)

References 14 publications

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“…The complexes trans-[Cr( [ 14] aneN4) (NH3)2] (CF3-S03)3 and franr-[Cr( [14]aneN4)(CN)2](CF3S03) and their deuterated derivatives were prepared by procedures analogous to those published for the PF6 salts. [1][2][3] The UV-visible spectra and luminescence properties of both compounds matched the literature data closely. 14]aneN4)(H20)2]2+ by MV2+ were determined by laser flash photolysis.…”

Section: Methodssupporting

confidence: 78%

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Electron-transfer and energy-transfer quenching of excited-state chromium(III) cyclam complexes and redox reactions of the chromium(II) product

Bakač¹,

Espenson²

1993

J. Phys. Chem.

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The 2E excited states trans-[*Cr ([ 14]aneN4)(NH3)2I3+ and trans-[*Cr ([ 14]aneN4)(CN)2]+ oxidize methyl viologen radical cation, MV+, in D20 with rate constants k = 1.09 X lo9 M-' s-I and 3.10 X lo9 M-1 s-1, respectively, at 298 K and 0.050 M ionic strength. The initial chromium(I1) products rapidly aquate to yield trans-[Cr( [ 14]aneN4)(H20)2]2+, which reduces MV2+ back to MV+. This reaction is strongly catalyzed by coordinating anions C1-, B r , and SCN-. For X = C1 and Br, the final chromium product is truns-[Cr([l4]-aneN4)(H20)(X)l2+. The kinetics obey a mixed third-order rate law, kobs = k,[MV2+] [trans-Cr-([14]aneN4)(H20)22+][X-], with kcl = 4.65 X lo5 M-2 s-l a nd kgr = 5.22 X lo5 M-2 s-l at 298 K and 0.25 M ionic strength. The SCN--catalyzed reaction has a more complex rate law and yields trans-[Cr([ 14laneN4)-(NCS)2]+ as the chromium product implying trans-[Cr( [ 14]aneN,)(NCS)2] as the sole kinetically important form of chromium(I1). The quenching of trans-[*Cr([l4]aneN4)(CN)2]+ by Cr(H20)62+ (k = 5.23 X lo7 M-I s-l), V ( H Z O )~~+ (k = 2.08 X lo'), and VO(H20)s2+ (k = 4.54 X lo6) takes place by energy transfer.

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Section: Methodssupporting

confidence: 78%

“…The excitation wavelength was typically 423 nm and occassionally 460 nm. The concentrations of the ground-state chromium complexes were (3-14) X 10-4 M and those of the excited states [1][2][3][4][5][6] µ . The latter were calculated from the change in [MV+] in the kinetic experiments.…”

Section: Solutions Of Methyl Viologen (Mv2+mentioning

confidence: 97%

Electron-transfer and energy-transfer quenching of excited-state chromium(III) cyclam complexes and redox reactions of the chromium(II) product

Bakač¹,

Espenson²

1993

J. Phys. Chem.

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“…for formation and dissociation reactions of the analogous Fe-(CN)5L(3~',,~complexes. [1][2][3][4][5]14 The enthalpies of activation associated with M are similar for the two systems while the entropy values are slightly lower (5-10 cal K"1 mol"1) for the ruthenium complexes. The decreased entropies of activation are suggestive of a shift from a purely dissociative (D) mechanism toward an interchange (I¿) process for the ruthenium system, but such a shift is not clearly supported by the kinetic behavior.…”

Section: Resultsmentioning

confidence: 96%

Kinetics and mechanism of the ligand substitution reactions of pentacyano(ligand)ruthenate(II) complexes

Hoddenbagh¹,

Macartney²

1986

Inorg. Chem.

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X-ray Structure Determination.7 Details of data collection and structure solution are summarized in Table I. Atomic coordinates are listed in Table II, and Table III contains selected bond lengths and angles. A picture of the molecule showing the atomic labeling scheme is presented in Figure 1.1 exists in the solid state in dimeric units. Two dmpm ligand molecules8 serve as bridges between the Ni(CO)2 groups forming an eight-membered ring. This ring adopts a boat conformation, and the halves of the molecule are related by a pseudo-2-fold axis.The nonbonded Ni-Ni distance is 4.39 Á.The coordination geometry of the Ni and P atoms may be described as tetrahedral with P-Ni-P angles of 108. 5 (1) and 109.2 (1)°. The P-C-P angles of 119.1 (1) and 119.5 (2)°a re 10°l arger than the ideal tetrahedral angle. The -P bond lengths of 2.200 (1)-2.219 (1) Á are somewhat longer than those observed in (dmpe)(PPh3)Ni(C2H4)3 and (dmpe)Ni(C2Ph2)4 (2.155-2.179 Á). The average P-C (bridging) distance in 1 (1.842 (5) Á) is comparable to known values.3,4 Inspection of intermolecular distances showed no contacts smaller than 3.5 Á (nonhydrogen atoms).Acknowledgment. We thank Professor O. Stelzer, Wuppertal, for a sample of dmpm and Dr. R. Mynott of this institute for the carbon-13 NMR studies. Supplementary Material Available: Tables of atomic coordinates and thermal parameters and bond lengths and angles (2 pages). Ordering information is given on any current masthead page. According to policy instituted Jan 1, 1986, the tables of calculated and observed structure factors (17 pages) are being retained in the editorial office for a period of 1 year following the appearance of this work in print. Inquiries for copies of these materials should be directed to the Editor.(7) In addition to several locally written programs, the following programs were used: tracer by Lawton and Jacobson for cell reduction; datap by Coppens, Leiserowitz, and Rabinovich for data reduction; difabs by Walker and Stuart for empirical absorption correction; Sheldrick's shelx-76/84 for Fourier calculations and initial least-squares refinement; gfmls, a highly modified version of orfls, by Hirshfeld, Coppens, Leiserowitz, and Rabinovich for subsequent full-matrix least-squares refinement; Davis' dabsd for bond distance and angle calculations; Roberts and Sheldrick's xanadu for best plane and torsion angle calculations; Johnson's ortbp for the molecular drawings. See: International Tables for X-ray Crystallography; Kynoch: Birmingham, Eng-

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“…The compound is of interest because it displays unusual phosphorescence behaviour in solution. It has also been described as exhibiting unusual behaviour in its visible emission spectrum (Kane-Maguire, 1983). Luminescence of the chromium(Ill) complex is thought to arise from the lowest component of the 2Tlg (Oh) electronic state.…”

mentioning

confidence: 99%

Structures of chromium(III) cyclam complexes. 1. Structure of trans-dicyano(1,4,8,11-tetraazacyclotetradecane)chromium(III) perchlorate

Hemmings¹,

Lisgarten²,

Palmer³

et al. 1990

Acta Crystallogr C

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Synthesis and characterization of trans-dicyano(1,4,8,11-tetraazacyclotetradecane) chromium(III) perchlorate [1]

Cited by 32 publications

References 14 publications

Electron-transfer and energy-transfer quenching of excited-state chromium(III) cyclam complexes and redox reactions of the chromium(II) product

Electron-transfer and energy-transfer quenching of excited-state chromium(III) cyclam complexes and redox reactions of the chromium(II) product

Kinetics and mechanism of the ligand substitution reactions of pentacyano(ligand)ruthenate(II) complexes

Structures of chromium(III) cyclam complexes. 1. Structure of trans-dicyano(1,4,8,11-tetraazacyclotetradecane)chromium(III) perchlorate

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