Structure of the copper tripodal Schiff base complex {tris[4-(2-thienyl)-3-aza-κN-3-butenyl]amine-κN}copper(I) tetrafluoroborate

The copper Schiff base complex {tris[4-(2-thienyl)-3- aza-~N-3-butenyl]amine-~N} copper(I) tetrafluoroborate, [Cu{N(CTHgNS)3 }]+.BF4- (I), crystallizes with the cation residing in a general position and two disordered tetrafluoroborate anions residing on twofold axes. The cation has approximate threefold symmetry and the copper(I) geometry is distorted trigonal pyramidal with coordination from the apical tertiary amine N atom and the three azomethine N atoms but not from the S atoms of the three thiophene moieties. The principal bond lengths are Cu-- Napical 2.300 (5) ,~ and mean Cu--Nequatorial 1.994 (4) A,, with a mean Cu-..S contact of 3.270 (2) A

Three-dimensional dynamical and chemical modelling of the upper atmosphere

Progress in coding a 3-D upper atmospheric model and in modeling the ozone perturbation resulting from the shuttle booster exhaust is reported. A time-dependent version of a 2-D model was studied and the sulfur cycle in the stratosphere was investigated. The role of meteorology in influencing stratospheric composition measurements was also studied

Improvements in the perturbation simulations of the global reference atmospheric model

The Global Reference Atmospheric Model (GRAM) program includes the capability for simulating pseudo-random perturbations in density, temperature, pressure, or wind components along a simulated reentry trajectory or other path through the atmosphere. Some concerns were expressed by GRAM users, however, that the mean-square perturbation gradients may be too large for small values of the vertical separation Delta z. The present GRAM perturbation simulations, based on a one-step autoregressive model, yield a power spectrum versus wavenumber k which is proportional to k sup -2 at high wavenumbers. This feature also produces mean-square perturbation differences which are directly proportional to Delta z, and mean-square perturbation gradients which are inversely proportional to Delta z. Thus, root-mean-square gradients, (Delta f/Delta z) sub rms, increase with decreasing Delta a as Delta z sup -1/2. A simple modification to GRAM is suggested which overcomes this problem, i.e., which produce root-mean-square gradient that remain bound as Delta z approaches zero. Possible applications of more sophisticated simulation approaches, e.g., second order autoregressive models, or fractal model techniques, were also explored briefly but found to yield improvements which appear too small to justify their considerable added complexity for use in the GRAM programs

Improvements in the Global Reference Atmospheric Model and comparisons with a global 3-D numerical model

The status of the Global Reference Atmospheric Model (GRAM) and the Mars Global Reference Atmospheric Model (MARS-GRAM) is reviewed. The wavelike perturbations observed in the Viking 1 and 2 surface pressure data, in the Mariner 9 IR spectroscopy data, and in the Viking 1 and 2 lander entry profiles were studied and the results interpreted

Structure of 5-phenyldibenzophosphole

C~sH13P, Mr = 260.3, orthorhombic, Pbc2~ [alternative setting of Pca2~ (No.29)], a = 8.486 (2), b = 12.387 (3), c = 26.244 (5) A, V= 2759 (1) A 3, Z = 8, Dx=l.25gcm -3, a(MoKa)=0.71073A, i z= 1.8 cm-~, F(000) = 1088, T= 288 K, R = 0.050 for 1512 observed reflections. The structure contains two 5-phenyldibenzophosphole molecules per asymmetric unit and these have almost identical conformations in the crystal lattice [as defined by the torsion angles C(ll)--P(1A)--C(31)--C(32) 32.0(5) and C(41)-- P(2A)--C(61)~C(62) 34.1 (6)°]. The central fivemembered rings in both molecules have envelope conformations, with the P atom 0.136(15) and 0.104(15) A from the relevant four-C-atom plane; the dibenzophosphole moieties are both bowed slightly, with the aromatic rings bent in a direction away from the pendant phenyl ring bonded to the P atom [dihedral angles between the plane of the C atoms of the central ring and the aromatic rings are in the range 1.1 (4)-3.0 (4)°]. There is also a small rotation about the central C--C bond as shown by the relevant torsion angles which are in the range 0.2 (5)-3.3 (6) ° . Difference maps show that there is disorder in the crystal lattice in that each molecule is disordered over two sites [a major and a minor one in each case; occupancies 0.89 and 0.11 for molecule (1) and 0.95 and 0.05 for molecule (2)]. For the minor sites, only the P atoms could be detected. Main dimensions are: P--C(phenyl) 1.841(9), 1.846 (10) A, P--C(dibenzophosphole) 1.808 (9)- 1.838(10), mean 1.819 (9) A, phosphole ring C--P--C 88.9 (4) and 89.5 (4) °, exocyclic C--P--C 101.7 (4)-104.2 (4), mean 103.0 (4) °

Structural Studies of Steric Effects in Phosphine Complexes: Dimers of Bis-{dithiocyanato(1-phenyl-dibenzophosphole)mercury(II)} Associate with Significant Hg−N and Hg−S Interdimer Interactions

The title compound, [Hg(SCN)2(C6H5)P(C12H8)]2, exists as a dimer with two-fold crystallographic symmetry in the solid state with the Hg atoms linked by bridging N- and S-thiocyanato atoms. There are four primary bonds to each Hg atom, Hg−N, 2.771(4) A, Hg−P, 2.4084(11) Å and two Hg−S, 2.4565(10) Å and 2.6055(13) Å, result-ing in a distorted trigonal pyramidal geometry about the metal centre. The dimers associate about inversion centres to form infinite one-dimensional chains by weaker Hg⋅⋅⋅N 3.178(5) Å and Hg⋅⋅⋅S 3.6027(14) Å interactions, giving an overall distorted octahedral coordination geometry for each Hg atom. The Hg⋅⋅⋅P bond lies approximately orthogonal to the ⋅⋅Hg⋅⋅Hg⋅⋅ chain and the benzophosphole group forms a \u27sandwich5 preventing interactions between the Hg(SCN)2 moieties in neighbouring chains

Structural Studies of Steric Effects in Phosphine Complexes: Dimers of Bis-{dithiocyanato(1-phenyl-dibenzophosphole)mercury(II)} Associate with Significant Hg−N and Hg−S Interdimer Interactions

The title compound, [Hg(SCN)2(C6H5)P(C12H8)]2, exists as a dimer with two-fold crystallographic symmetry in the solid state with the Hg atoms linked by bridging N- and S-thiocyanato atoms. There are four primary bonds to each Hg atom, Hg−N, 2.771(4) A, Hg−P, 2.4084(11) Å and two Hg−S, 2.4565(10) Å and 2.6055(13) Å, result-ing in a distorted trigonal pyramidal geometry about the metal centre. The dimers associate about inversion centres to form infinite one-dimensional chains by weaker Hg⋅⋅⋅N 3.178(5) Å and Hg⋅⋅⋅S 3.6027(14) Å interactions, giving an overall distorted octahedral coordination geometry for each Hg atom. The Hg⋅⋅⋅P bond lies approximately orthogonal to the ⋅⋅Hg⋅⋅Hg⋅⋅ chain and the benzophosphole group forms a \u27sandwich5 preventing interactions between the Hg(SCN)2 moieties in neighbouring chains

Analysis of the feasibility of an experiment to measure carbon monoxide in the atmosphere

The feasibility of measuring atmospheric carbon monoxide from a remote platform using the correlation interferometry technique was considered. It has been determined that CO data can be obtained with an accuracy of 10 percent using this technique on the first overtone band of CO at 2.3 mu. That band has been found to be much more suitable than the stronger fundamental band at 4.6 mu. Calculations for both wavelengths are presented which illustrate the effects of atmospheric temperature profiles, inversion layers, ground temperature and emissivity, CO profile, reflectivity, and atmospheric pressure. The applicable radiative transfer theory on which these calculations are based is described together with the principles of the technique

The NASA/MSFC global reference atmospheric model: 1990 version (GRAM-90). Part 1: Technical/users manual

A technical description of the NASA/MSFC Global Reference Atmospheric Model 1990 version (GRAM-90) is presented with emphasis on the additions and new user's manual descriptions of the program operation aspects of the revised model. Some sample results for the new middle atmosphere section and comparisons with results from a three dimensional circulation model are provided. A programmer's manual with more details for those wishing to make their own GRAM program adaptations is also presented

The NASA/MSFC global reference atmospheric model: 1990 version (GRAM-90). Part 2: Program/data listings

A new (1990) version of the NASA/MSFC Global Reference Atmospheric Model (GRAM-90) was completed and the program and key data base listing are presented. GRAM-90 incorporate extensive new data, mostly collected under the Middle Atmosphere Program, to produce a completely revised middle atmosphere model (20 to 120 km). At altitudes greater than 120 km, GRAM-90 uses the NASA Marshall Engineering Thermosphere model. Complete listings of all program and major data bases are presented. Also, a test case is included