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2. Nonlinear Optical Properties of Porphyrins

Author

Senge, M. O., primary, Fazekas, M., additional, Notaras, E. G. A., additional, Blau, W. J., additional, Zawadzka, M., additional, Locos, O. B., additional, and Ni Mhuircheartaigh, E. M., additional

Published
2007
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5. Mixed-Metal Cluster Chemistry. 23. Synthesis and Crystallographic and Electrochemical Studies of Alkyne-Coordinated Group 6−Iridium Clusters Linked by Heterocyclic Groups

Author

Notaras, E. G. A., Lucas, N. T., Humphrey, M. G., Willis, A. C., and Rae, A. D.

Abstract

Reaction between the tetrahedral cluster compound Mo2Ir2(CO)10(η5-C5H4Me)2 (1) and 2-iodo-5-(oct-1‘-ynyl)thiophene afforded the pseudooctahedral cluster Mo2Ir2{μ4-η2-Me(CH2)5C2-5-C4H2S-2-I}(CO)8(η5-C5H4Me)2 (17) by formal insertion of the alkyne C&tbd1;C group into the Mo−Mo bond. Similar reactions of 1 or W2Ir2(CO)10(η5-C5H4Me)2 (2) with heterocyclic di- or triynes afforded the related mono-, di-, or tricluster compounds [M2Ir2(CO)8(η5-C5H4Me)2]2{μ8-η4-Me(CH2)5C2-2-C4H2E-5-C2(CH2)5Me} [E = S, M = Mo (20), W (21); E = Se, M = Mo (30), W (31)], [M2Ir2(CO)8(η5-C5H4Me)2]2{μ8-η4-Me(CH2)5C2-2-C4H2S-5-(E)-CH&dbd;CH-2-C4H2S-5-C2(CH2)5Me} [M = Mo (22), W (24)], M2Ir2{μ4-η2-Me(CH2)5C2-2-C4H2S-5-(E)-CH&dbd;CH-2-C4H2S-5-C&tbd1;C(CH2)5Me}(CO)8(η5-C5H4Me)2 [M = Mo (23), W (25)], [M2Ir2(CO)8(η5-C5H4Me)2]3{μ12-η6-Me(CH2)5C2-2-C4H2S-5-C2-2-C4H2S-5-C2(CH2)5Me} [M = Mo (26), W (28)], and [M2Ir2(CO)8(η5-C5H4Me)2]2{μ8-η4-Me(CH2)5C2-2-C4H2S-5-C2-2-C4H2S-5-C&tbd1;C(CH2)5Me} [M = Mo (27), W (29)]. Compounds 27 and 29 correspond to the 1,2-dicluster adducts of the linear triyne Me(CH2)5C&tbd1;C-5-C4H2S-2-C&tbd1;C-2-C4H2S-5-C&tbd1;C(CH2)5Me. No 1,3-dicluster isomer was isolated from direct reaction, but the molybdenum-containing 1,3-dicluster isomer was prepared by exploiting organic reaction chemistry on precoordinated functionalized alkyne ligands. Thus, Sonogashira coupling of 17 with trimethylsilylacetylene and subsequent desilylation gave Mo2Ir2{μ4-η2-Me(CH2)5C2-5-C4H2S-2-C&tbd1;CR}(CO)8(η5-C5H4Me)2 [R = SiMe3 (18), H (19)]. Sonogashira coupling of 17 and 19 gave the 1,3-isomer [Mo2Ir2(CO)8(η5-C5H4Me)2]2{μ8-η4-Me(CH2)5C2-2-C4H2S-5-C&tbd1;C-2-C4H2S-5-C2(CH2)5Me} (32), as well as the homocoupling product [Mo2Ir2(CO)8(η5-C5H4Me)2]2{μ8-η4-Me(CH2)5C2-2-C4H2S-5-C&tbd1;CC&tbd1;C-2-C4H2S-5-C2(CH2)5Me} (33). The identities of 21, 29, and 31 were confirmed by single-crystal X-ray diffraction studies. Cyclic voltammetric scans for these complexes all show a reversible/quasi-reversible oxidation followed by an irreversible oxidation process. Dicluster compounds linked by one heterocycle, and tricluster compounds, show two reduction processes, whereas dicluster compounds with longer bridges reveal only one reduction process.

Published
2003

6. Mixed-Metal Cluster Chemistry. 22. Synthesis and Crystallographic, Electrochemical, and Theoretical Studies of Alkyne-Coordinated Group 6−Iridium Clusters Linked by Phenyleneethynylene Groups

Author

Lucas, N. T., Notaras, E. G. A., Petrie, S., Stranger, R., and Humphrey, M. G.

Abstract

Reaction between the tetrahedral cluster compound Mo2Ir2(CO)10(η5-C5H4Me)2 (1) and 1-iodo-4-(oct-1‘-ynyl)benzene afforded the pseudooctahedral cluster Mo2Ir2{μ4-η2-Me(CH2)5C2-4-C6H4I}(CO)8(η5-C5H4Me)2 (7). Similar reactions of 1 and W2Ir2(CO)10(η5-C5H4Me)2 (2) with di- and triynes afforded the related mono-, di-, and tricluster compounds [M2Ir2(CO)8(η5-C5H4Me)2]3{μ12-η6-Me(CH2)5C2-4-C6H4C2C6H4-4-C2(CH2)5Me} (M = Mo (12), W (14)), [W2Ir2(CO)8(η5-C5H4Me)2]2{μ8-η4-Me(CH2)5C2-4-C6H4C2C6H4-4-C&tbd1;C(CH2)5Me} (13), Mo2Ir2{μ4-η2-Me(CH2)5C2C6H3-3,5-[C&tbd1;C(CH2)5Me]2}(CO)8(η5-C5H4Me)2 (15), and [Mo2Ir2(CO)8(η5-C5H4Me)2]2{μ8-η4-[Me(CH2)5C2]2-1,3-C6H3-5-C&tbd1;C(CH2)5Me} (16). Compound 13 corresponds to the 1,2-dicluster adduct of the linear triyne Me(CH2)5C&tbd1;C-4-C6H4C&tbd1;C-4-C6H4C&tbd1;C(CH2)5Me. No 1,3-dicluster isomer was isolated from direct reaction, but the related molybdenum-containing 1,3-dicluster isomer was prepared by exploiting organic reaction chemistry on precoordinated functionalized alkyne ligands. Thus, Sonogashira coupling of 7 with Me3SiC&tbd1;CH and subsequent desilylation afforded Mo2Ir2{μ4-η2-Me(CH2)5C2-4-C6H4C&tbd1;CR}(CO)8(η5-C5H4Me)2 (R = SiMe3 (8), H (9)). Sonogashira coupling of 7 and 9 gave the 1,3-isomer [Mo2Ir2(CO)8(η5-C5H4Me)2]2{μ8-η4-Me(CH2)5C2-4-C6H4C&tbd1;CC6H4-4-C2(CH2)5Me} (18), as well as the homocoupling product [Mo2Ir2(CO)8(η5-C5H4Me)2]2{μ8-η4-Me(CH2)5C2-4-C6H4C&tbd1;CC&tbd1;CC6H4-4-C2(CH2)5Me} (19); the identity of the latter was confirmed by a single-crystal X-ray diffraction study. Cyclic voltammetric scans for 12−14, 18, and 19 all show a reversible/quasi-reversible oxidation followed by an irreversible oxidation process. Compounds 18 and 19 (in which clusters are linked by long unsaturated bridges) exhibit one irreversible reduction process, whereas 12−14 (in which n cluster cores are linked by a phenylene unit) show n irreversible reduction processes. Density functional calculations indicate that oxidation and reduction both proceed with retention of the pseudooctahedral core geometry but that loss of a carbonyl ligand concomitant with two-electron reduction is energetically accessible, suggesting that this accounts for the irreversibility of the reduction step.

Published
2003

7. Mixed-Metal Cluster Chemistry. 21. Synthesis and Crystallographic and Electrochemical Studies of Alkyne-Coordinated Group 6−Iridium Clusters Linked by Phenylenevinylene Groups

Author

Lucas, N. T., Notaras, E. G. A., Cifuentes, M. P., and Humphrey, M. G.

Abstract

The pseudooctahedral monocluster compounds M2Ir2(μ4-η2-R1C2R2)(μ-CO)4(CO)4(η5-C5H4Me)2 (M = Mo, R2 = Ph, R1 = H (12), Ph (13), Me (14); M = W, R2 = Ph, R1 = Me (15); M = Mo, R1 = n-hexyl, R2 = C6H4-4-CHO (16), C6H4-4-CH2P(O)(OEt)2 (17)) have been prepared from reactions between the tetrahedral cluster compounds M2Ir2(CO)10(η5-C5H4Me)2 and the alkynes R1C2R2. Similar reactions between tetrahedral cluster precursors and di- or triynes have afforded the related compounds [M2Ir2(μ-CO)4(CO)4(η5-C5H4R)2]2(μ8-η4-R1C2BC2R1) (R = H, R1 = H, B = 4-C6H4-(E)-CH&dbd;CH-4-C6H4, M = Mo (18); R = Me, R1 = n-hexyl, B = 4-C6H4, M = Mo (19), W (20); R = Me, R1 = n-hexyl, B = 4-C6H4-(E)-CH&dbd;CH-4-C6H4, M = Mo (22), W (23); R = Me, R1 = n-hexyl, B = 4-C6H4-(E)-CH&dbd;CH-4-C6H4-(E)-CH&dbd;CH-4-C6H4, M = Mo (24); R = Me, R1 = H, B = (CH2)2, M = W (27)), [Mo2Ir2(μ-CO)4(CO)4(η5-C5H4Me)2]3{μ12-η6-1,3,5-C6H3[(E)-CH&dbd;CHC6H4-4‘-C2(CH2)5Me]3} (25), and W2Ir2(μ4-η2-R1C2R2)(μ-CO)4(CO)4(η5-C5H4Me)2 (R1 = n-hexyl, R2 = 4-C6H4C&tbd1;C(CH2)5Me (21); R1 = H, R2 = (CH2)2C&tbd1;CH (26)). Compounds 18−20 and 22−25 contain two or three cluster units linked by unsaturated bridges, while 27 contains two cluster units linked by a saturated bridge. Compound 22 was prepared in lower yield by coupling 16 and 17 under Emmons−Horner conditions. Structural studies of examples of mono- (15), di- (22), and tricluster (25) compounds have been undertaken. Cyclic voltammetric scans for 12−15, 19, 20, 22−24, 27 and the related cluster W2Ir2(μ4-η2-PhC2Ph)(μ-CO)4(CO)4(η5-C5H4Me)2 (4) have been collected. All compounds show a reversible/partially reversible oxidation, followed by an irreversible oxidation process; potentials for the former increase on replacement of tungsten by molybdenum and alkyne substituent variation Me < H < Ph. UV−vis−near-IR spectroelectrochemical studies of the first oxidation process for 12, 15, and 20 show similar spectral progressions for these mono- and dicluster compounds. The reductive cyclic voltammetric scans for 4, 12−15, 22−24, and 27 all show one irreversible reduction process; compounds 19 and 20, distinguished by possessing the shortest unsaturated bridge, show two reduction processes.

Published
2003

9. Experimentally induced active and quiet sleep engage non-overlapping transcriptional programs in Drosophila .

Author

Anthoney N, Tainton-Heap L, Luong H, Notaras E, Kewin AB, Zhao Q, Perry T, Batterham P, Shaw PJ, and van Swinderen B

Subjects
Animals, Sleep genetics, Sleep, REM, Brain, Mammals, Drosophila, Drosophila melanogaster genetics
Abstract

Sleep in mammals can be broadly classified into two different physiological categories: rapid eye movement (REM) sleep and slow-wave sleep (SWS), and accordingly REM and SWS are thought to achieve a different set of functions. The fruit fly Drosophila melanogaster is increasingly being used as a model to understand sleep functions, although it remains unclear if the fly brain also engages in different kinds of sleep as well. Here, we compare two commonly used approaches for studying sleep experimentally in Drosophila : optogenetic activation of sleep-promoting neurons and provision of a sleep-promoting drug, gaboxadol. We find that these different sleep-induction methods have similar effects on increasing sleep duration, but divergent effects on brain activity. Transcriptomic analysis reveals that drug-induced deep sleep ('quiet' sleep) mostly downregulates metabolism genes, whereas optogenetic 'active' sleep upregulates a wide range of genes relevant to normal waking functions. This suggests that optogenetics and pharmacological induction of sleep in Drosophila promote different features of sleep, which engage different sets of genes to achieve their respective functions., Competing Interests: NA, LT, HL, EN, AK, QZ, TP, PB, PS, Bv No competing interests declared, (© 2023, Anthoney et al.)

Published
2023
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10. Esophageal dysmotility in brothers with an FG-like syndrome.

Author

Smith RL, Edwards MJ, Notaras E, and O'Loughlin EV

Subjects
Child, Child, Preschool, Constipation, Crying, Humans, Infant, Infant, Newborn, Male, Manometry, Nuclear Family, Syndrome, Abnormalities, Multiple diagnosis, Esophageal Motility Disorders diagnosis, Sex Chromosome Aberrations diagnosis, X Chromosome
Abstract

We present 4 brothers with developmental delay, minor anomalies, and symptoms due to gastrointestinal dysmotility. There was some resemblance with FG syndrome, although none of the brothers had sufficient findings to make this diagnosis. The index case presented with at age 1 month with screaming episodes, mild gastro-esophageal reflux (GER), and severe constipation. Esophageal manometry studies were consistent with the diagnosis of "nutcracker esophagus." Symptomatic and manometric improvement followed treatment with oral calcium channel blockers. Two older and less severely affected brothers had similar manometric findings but did not require treatment. A fourth brother with symptoms in infancy now has normal esophageal manometry findings. These boys in all likelihood have an X-linked syndrome with manifestations of FG syndrome, in which treatment with calcium channel blockers, produces clinical and manometric improvement. The FG syndrome is an X-linked syndrome of multiple congenital anomalies/mental retardation with facultative manifestations of gastrointestinal dysmotility, including gastro-esophageal reflux, severe feeding difficulties, and constipation. Esophageal dysmotility, in particular "nutcracker esophagus," should be suspected in infants with the FG syndrome and screaming attacks., (Copyright 2000 Wiley-Liss, Inc.)

Published
2000

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