title: Germanium hydride derivatives of transition metal carbonyls

authors: Christie, Judy A.

abstract: Compounds of the type Fe(CO)₄(GeR₃)₂ containing two different methylgermyl substituents have been prepared and characterised. The preparation was via the exchange reaction

Fe(CO)₄(GeR₃)₂ + [Mn(CO)₅]⁻ → [Fe(CO)₄(GeR₃)]⁻ + Mn(CO)₅(GeR₃)

[Fe(CO)₄(GeR₃)]⁻ + GeXR’₃ → Fe(CO)₄(GeR₃)(GeR’₃)


The compounds characterised were Fe(CO)₄(GeMeH₂) (GeH₃) Fe(CO)₄(GeMe₂H) (GeH₃), Fe(CO)₄ (GeMe₂H) (GeMeH₂), Fe(CO)₄(GeMe₃) (GeH₃) Fe(CO)₄(GeMe₃)(GeMeH₂) and Fe(CO)₄(GeMe₃)(GeMe₂H). Of these, the species Fe(CO)₄(GeMeH₂) (GeH₃) were characterised fully by infrared, proton nmr and mass spectroscopic studies.


The self-reaction 

2Fe(CO)₄(GeR₃)₂ → [Fe(CO)₄(GeR₂)]₂ + 2GeR₄

has also been examined in some detail. The methylgermane was eliminated in preference to GeH₄ and species of the type [Fe(CO)₄(GeH₃)]₂-GeR₂ were also identified in two cases. 

Halogenation of Fe(CO)₄(GeMeH₃) (GeH₃) and Fe(CO)₄(GeMe₂H) (GeH3) was followed by ¹H nmr studies. CCℓ₄ results in the substitution of Ge-H, while HCℓ cleaves Fe-Ge bonds. 

While Fe(CO)₄(GeMe₂H) (GeMeH₂), Fe(CO)₄(GeMe₃) (GeMeH₂) and Fe(CO)₄(GeMe₃) (GeMe₂H) have been prepared, spectroscopic identification of these species is rather tenuous as these samples were found always to be contaminated with either the symmetrically substituted species Fe(CO)₄(GeR₃)₂ and/or products from the self-reaction. 

Mn(CO)₅(GeR₃) species obtained in the above syntheses react with Co₂(CO)₈ to yield the species [Co₃ (CO)₉][Mn(CO)₅]Ge, [Co₂(CO)₇[Mn(CO)₅]GeMe and possibly [Co(CO)₄][Mn(CO)₅]GeMe₂. 

These species were characterised by their infrared and mass spectroscopic properties.

text: Germanium hydride derivatives of transition metal carbonyls Compounds of the type Fe(CO)₄(GeR₃)₂ containing two different methylgermyl substituents have been prepared and characterised. The preparation was via the exchange reaction

Fe(CO)₄(GeR₃)₂ + [Mn(CO)₅]⁻ → [Fe(CO)₄(GeR₃)]⁻ + Mn(CO)₅(GeR₃)

[Fe(CO)₄(GeR₃)]⁻ + GeXR’₃ → Fe(CO)₄(GeR₃)(GeR’₃)


The compounds characterised were Fe(CO)₄(GeMeH₂) (GeH₃) Fe(CO)₄(GeMe₂H) (GeH₃), Fe(CO)₄ (GeMe₂H) (GeMeH₂), Fe(CO)₄(GeMe₃) (GeH₃) Fe(CO)₄(GeMe₃)(GeMeH₂) and Fe(CO)₄(GeMe₃)(GeMe₂H). Of these, the species Fe(CO)₄(GeMeH₂) (GeH₃) were characterised fully by infrared, proton nmr and mass spectroscopic studies.


The self-reaction 

2Fe(CO)₄(GeR₃)₂ → [Fe(CO)₄(GeR₂)]₂ + 2GeR₄

has also been examined in some detail. The methylgermane was eliminated in preference to GeH₄ and species of the type [Fe(CO)₄(GeH₃)]₂-GeR₂ were also identified in two cases. 

Halogenation of Fe(CO)₄(GeMeH₃) (GeH₃) and Fe(CO)₄(GeMe₂H) (GeH3) was followed by ¹H nmr studies. CCℓ₄ results in the substitution of Ge-H, while HCℓ cleaves Fe-Ge bonds. 

While Fe(CO)₄(GeMe₂H) (GeMeH₂), Fe(CO)₄(GeMe₃) (GeMeH₂) and Fe(CO)₄(GeMe₃) (GeMe₂H) have been prepared, spectroscopic identification of these species is rather tenuous as these samples were found always to be contaminated with either the symmetrically substituted species Fe(CO)₄(GeR₃)₂ and/or products from the self-reaction. 

Mn(CO)₅(GeR₃) species obtained in the above syntheses react with Co₂(CO)₈ to yield the species [Co₃ (CO)₉][Mn(CO)₅]Ge, [Co₂(CO)₇[Mn(CO)₅]GeMe and possibly [Co(CO)₄][Mn(CO)₅]GeMe₂. 

These species were characterised by their infrared and mass spectroscopic properties.

year: 1981

title: Spatially varying drag within a wave-exposed mangrove forest and on the adjacent tidal flat

authors: Mullarney, Julia C.

subjects: Mekong Delta

abstract: Mangroves have been shown to protect shorelines against damage from the combined hydrodynamic forces of waves and tides, owing to the presence of roots (pneumatophores) and tree trunks that enhance vegetative drag. However, field measurements within these environments are limited. We present field observations of flows from the seaward coast of Cù Lao Dung Island (Sóc Trăng Province) in the Mekong Delta, Vietnam. Measurements were made in two different seasons along a transect that crosses from mudflats to mangrove forest. Flows are also explored using an idealised numerical model. Both the data and model capture the flow transitions from mudflat across the fringing region to the forest interior. We observe a rotation of the obliquely incident flows toward an orientation nearly perpendicular to the vegetated/unvegetated boundary. The momentum balances governing the large-scale flow are assessed and indicate the relative importance of friction, winds and depth-averaged pressure forces. In the forest, drag coefficients were 10-30 times greater than values usually observed for bottom friction, with particularly effective friction in the regions of dense pneumatophores at the fringe and when water depths were lower than the height of the pneumatophores. Pressure gradient balances suggest that the drag induced by bottom friction from pneumatophores was dominant relative to drag from the larger, but sparser, tree trunks.

text: Spatially varying drag within a wave-exposed mangrove forest and on the adjacent tidal flat Mangroves have been shown to protect shorelines against damage from the combined hydrodynamic forces of waves and tides, owing to the presence of roots (pneumatophores) and tree trunks that enhance vegetative drag. However, field measurements within these environments are limited. We present field observations of flows from the seaward coast of Cù Lao Dung Island (Sóc Trăng Province) in the Mekong Delta, Vietnam. Measurements were made in two different seasons along a transect that crosses from mudflats to mangrove forest. Flows are also explored using an idealised numerical model. Both the data and model capture the flow transitions from mudflat across the fringing region to the forest interior. We observe a rotation of the obliquely incident flows toward an orientation nearly perpendicular to the vegetated/unvegetated boundary. The momentum balances governing the large-scale flow are assessed and indicate the relative importance of friction, winds and depth-averaged pressure forces. In the forest, drag coefficients were 10-30 times greater than values usually observed for bottom friction, with particularly effective friction in the regions of dense pneumatophores at the fringe and when water depths were lower than the height of the pneumatophores. Pressure gradient balances suggest that the drag induced by bottom friction from pneumatophores was dominant relative to drag from the larger, but sparser, tree trunks.

year: 2017

title: E hoki mai nei ki te ūkaipō | Return to your place of nourishment [Te Kōputu a te Whanga a Toi | Whakatāne Art Gallery]

authors: Apiata, Hāwea

subjects: toi Māori

abstract: E Hoki Mai Nei ki te Ūkaipō | Return to Your Place of Nourishment brings together works by four wāhine Māori artists, Aimee Ratana, Aisha Roberts, Hollie Tawhiao and Maraea Timutimu, which explore narratives of pakanga
(conflict) through toi (art). In this show, the four artists weave together their unique practices and stories to present a cohesive yet diverse examination of conflicts, with a particular focus on the artists’ own whānau, hapū, and iwi narratives.
Curated by Hāwea Apiata.

text: E hoki mai nei ki te ūkaipō | Return to your place of nourishment [Te Kōputu a te Whanga a Toi | Whakatāne Art Gallery] E Hoki Mai Nei ki te Ūkaipō | Return to Your Place of Nourishment brings together works by four wāhine Māori artists, Aimee Ratana, Aisha Roberts, Hollie Tawhiao and Maraea Timutimu, which explore narratives of pakanga
(conflict) through toi (art). In this show, the four artists weave together their unique practices and stories to present a cohesive yet diverse examination of conflicts, with a particular focus on the artists’ own whānau, hapū, and iwi narratives.
Curated by Hāwea Apiata.

year: 2025-04-17