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PubMed · 11670050

Apically Linked Small Metallacarborane Clusters. Directed Synthesis and Structural Characterization of 7,7'-[CpCo(2,3-Et(2)C(2)B(4)H(3)](2) and [CpCo(2,3-Et(2)C(2)B(4)H(3)-7)](2)X Complexes (X = MeCH, HC=CH, C&tbd1;C)(,)(1).

Michael A. Curtis·Thomas Müller·Volker Beez·Hans Pritzkow·Walter Siebert·Russell N. Grimes
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Abstract

A series of novel bis(cobaltacarboranyl) (CoC(2)B(4))(2)X dicluster complexes whose B(7) (apex) atoms are linked by organic moieties involving sp-, sp(2)-, or sp(3)-hybridized carbon, or by a direct B(7)-B(7') bond, has been prepared by extension of the recently described "recapitation" method (Curtis, M. A.; et al. Inorg. Chem. 1996, 35, 6703) that entails treatment of 6-vertex nido-CoC(2)B(3) dianions with monoboron reagents. Reactions of Li(2)[nido-CpCo(Et(2)C(2)B(3)H(3))] in toluene with MeCH(BCl(2))(2) and with cis-(BCl(2))C(2)H(2) gave, respectively, [CpCo(2,3-Et(2)C(2)B(4)H(3)-7-)](2)MeCH (5) and cis-[CpCo(2,3-Et(2)C(2)B(4)H(3)-7-)](2)C(2)H(2) (6a) following chromatographic separation. Ultraviolet irradiation of 6a induced partial conversion to the trans isomer 6b, affording a 46:54 trans/cis equilibrium mixture in 84 h. Reactions of the same cobaltacarborane dianion with bis(catecholboryl)acetylene and with bis(catecholdiboryl) gave [CpCo(2,3-Et(2)C(2)B(4)H(3)-7-)](2)C(2) (7) and [CpCo(2,3-Et(2)C(2)B(4)H(3)-7-)](2) (8), respectively. The new complexes were isolated as air-stable, crystalline orange solids and were characterized from their (1)H, (11)B, and (13)C NMR, IR, UV-visible, and mass spectra, supported by X-ray crystallographic studies of 5, 6a, 7, and 8. Crystal data for 5: space group P2(1)ca (orthorhombic); a = 14.220(10) Å, b = 15.690(10) Å, c = 16.860(10) Å, Z = 4; R = 0.041 for 7485 independent reflections. Crystal data for 6a: space group C2/c (monoclinic); a = 12.849(6) Å, b = 11.435(6) Å, c = 25.619(13) Å, beta = 96.230(10) degrees; Z = 4; R = 0.036 for 5440 independent reflections. Crystal data for 7: space group P2(1)/n (monoclinic); a = 17.298(12) Å, b = 13.932(10) Å, c = 30.82(2) Å, beta = 96.34(5) degrees; Z = 8; R = 0.070 for 9632 independent reflections. Crystal data for 8: space group P&onemacr; (triclinic); a = 9.150(10) Å, b = 10.270(10) Å, c = 10.340(10) Å, alpha = 84.52(5) degrees, beta = 78.05(5) degrees, gamma = 68.6(5) degrees; Z = 1; R = 0.056 for 5154 independent reflections.

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Michael A. Curtis, Thomas Müller, Volker Beez, Hans Pritzkow, Walter Siebert, Russell N. Grimes. 1997-08-13. Apically Linked Small Metallacarborane Clusters. Directed Synthesis and Structural Characterization of 7,7'-[CpCo(2,3-Et(2)C(2)B(4)H(3)](2) and [CpCo(2,3-Et(2)C(2)B(4)H(3)-7)](2)X Complexes (X = MeCH, HC=CH, C&tbd1;C)(,)(1).. https://doi.org/10.1021/ic970221e

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BACKGROUND: Frailty is a major risk factor for influenza-related complications and can influence vaccine effectiveness. We aimed to assess the relative vaccine effectiveness (rVE) of high-dose (HD-IIV) versus standard-dose inactivated influenza vaccine (SD-IIV) in older adults aged 65 years or older according to frailty risk. METHODS: This study was a prespecified analysis of DANFLU-2, an open-label, individually randomised trial, conducted in Denmark during three consecutive influenza seasons (2022-23, 2023-24, and 2024-25). Adults aged 65 years or older were randomised (1:1) to the HD-IIV or SD-IIV group. The primary endpoint was hospitalisation for influenza or pneumonia. Frailty was defined according to the validated Hospital Frailty Risk Score (HFRS) based on ICD-10 codes within 10 years before randomisation. Participants were stratified into three HFRS categories, namely low (<5 points), intermediate (5-15 points), and high (>15 points) frailty risk. The rVE of HD-IIV versus SD-IIV against the primary endpoint was assessed across prespecified HFRS categories and treating HFRS as a continuous variable. Pearson's chi-square test was used to compare safety events across frailty risk groups and randomisation groups. FINDINGS: Among 332&#x2009;438 randomised participants (mean age 73&#xb7;7 years [SD 5&#xb7;8]; 161&#x2009;538 [48&#xb7;6%] were female), 276&#x2009;173 (83&#xb7;1%) had low frailty risk, 52&#x2009;395 (15&#xb7;8%) had intermediate frailty risk, and 3861 (1&#xb7;2%) had high frailty risk. The primary endpoint of hospitalisation for influenza or pneumonia occurred in 1424 (0&#xb7;5%) of 276&#x2009;173 participants with low frailty risk, 761 (1&#xb7;5%) of 52&#x2009;395 with intermediate frailty risk, and 163 (4&#xb7;2%) of 3861 with high frailty risk (relative risk [RR] for intermediate vs low frailty risk 2&#xb7;8 [95% CI 2&#xb7;6-3&#xb7;1]; RR for high vs low frailty risk 8&#xb7;2 [7&#xb7;0-9&#xb7;6]). HFRS as a continuous variable significantly modified the effect of HD-IIV versus SD-IIV against the primary endpoint with higher rVE estimates with increasing HFRS (pinteraction=0&#xb7;020). The rVE was 0&#xb7;2% (95% CI -10&#xb7;8 to 10&#xb7;2) among those with low frailty risk, 13&#xb7;1% (-0&#xb7;4 to 24&#xb7;8) among those with intermediate frailty risk, and 19&#xb7;9% (-10&#xb7;3 to 42&#xb7;1) among those with high frailty risk. No significant interaction was observed when HFRS was assessed according to the prespecified categorical frailty groups (pinteraction=0&#xb7;17). The proportion of participants with at least one serious adverse event increased across frailty risk groups (13&#x2009;366 [4&#xb7;8%] of 275&#x2009;795 for low frailty risk, 5475 [10&#xb7;5%] of 52&#x2009;315 for intermediate frailty risk, and 777 [20&#xb7;2%] of 3850 for high frailty risk; p<0&#xb7;0001), with similar proportions of serious adverse events in the HD-IIV and SD-IIV groups for each frailty risk group. INTERPRETATION: Among adults aged 65 years or older in Denmark, frailty risk might modify the effects of HD-IIV versus SD-IIV against hospitalisation for influenza or pneumonia, with higher rVE estimates with increasing frailty risk. These findings might support considering high-dose influenza vaccines for frail older adults. However, effect modification was not evident when frailty was assessed using prespecified categorical subgroups, and subgroup-specific estimates were imprecise, with 95% CIs crossing the null. These results should be considered exploratory, warranting further investigation. FUNDING: The DANFLU-2 trial was funded by Sanofi.

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