Secondary Cl Research Articles

Heavy-Metal π Complexes. 13. Trichloro(1,2,3-trimethylbenzene)bismuth(III)

The title compound, [BiCl3(1,2,3-Me3C6H3)], contains quasi-dimeric units of arene-coordinated BiCl3 fragments that are further associated via additional Bi—Cl contacts to form coordination-polymeric layers. The resulting coordination number of Bi is 3 + 3 + 1 (primary + secondary Cl contacts + arene). The Bi—arene bonding is characterized by Bi—C distances in the range 3.168 (7)–3.751 (8) Å.

Tieftemperatur-Kristallstruktur von Dichlormonoxid, Cl2O

Abstract The crystal structure of dichlorine oxide is reported. Cl2O crystallizes in the tetragonal space group I41/amd with a = 772.46(5) pm, c = 926.06(7) pm, and Z = 8 at 90 K. Basically a molecular structure (d(O–Cl) = 170.92(4) pm) with weak secondary Cl–O interactions (d(O … Cl) = 279.86(4) pm) results in a distorted tetrahedral coordination of the oxygen atom. Cl2O is isostructural to the high-pressure modification of water, ice VIII.

Ancillary follicle and secondary corpora lutea formation following exogenous gonadotropin treatment in the domestic cat and effect of passive transfer of gonadotropin-neutralizing antisera

A combination regimen of equine chorionic gonadotropin (eCG) and human chorionic gonadotropin (hCG) was used to stimulate ovarian follicular development in domestic cats. The rate of elimination of eCG from circulation was estimated, and, following follicular aspiration, the formation of ancillary follicles and secondary CL was characterized. The effect of gonadotropin-neutralizing antisera on the development of secondary ovarian structures, CL function and humoral immune responses also was evaluated. After intramuscular injection, initial serum eCG concentrations were variable, with the elimination half-life estimated at 39 to 55 h and eCG persisting in circulation for several days. Following follicular aspiration, queens formed CL equal to the number of aspirated follicles and exhibited a rapid increase in progesterone concentration but developed high numbers of ancillary follicles by 5 d post aspiration. By 15 d post aspiration, all ancillary follicles had luteinized to form secondary CL. Treatment with neutralizing antisera at the time of follicular aspiration slowed (P < 0.05) CL formation but did not decrease (P > 0.05) the number of ancillary follicles or secondary CL. Progesterone concentrations did not differ (P > 0.05) from control queens while secondary humoral immune responses to eCG were qualitatively similar between groups. In summary, eCG was eliminated slowly from cats following intramuscular injection and this persistence in circulation may have contributed to the development of ancillary follicles and secondary CL. However, the administration of neutralizing antisera at the time of follicular aspiration was ineffective in preventing the formation of these secondary ovarian structures.

Odor-induced currents in Xenopus olfactory receptor cells measured with perforated-patch recording.

1. Odor-evoked currents were recorded in Xenopus laevis olfactory receptor neurons (ORNs) by the use of conventional, as well as nystatin and gramicidin-perforated, whole cell recording. The odor-evoked current ran down quickly in conventional, but not in perforated, whole cell recording. All three types of recording gave similar values for the amplitude, latency, time-to-peak, recovery time, and reversal potential of the odor-evoked current. 2. A secondary Cl current comprised a significant part of the odor-evoked current (55-65%). ECl measured by gramicidin perforation, which does not alter [Cl-]i, was -2.3 +/- 5.0 (SE) mV, indicating that these neurons maintain a high [Cl-]i and that the secondary Cl current plays an excitatory role in olfactory transduction.

Characterization of boron-doped diamond films using (CH 4-CO 2) gas mixtures with B(OCH 3) 3 as a dopant source by MPCVD

Boron-doped diamond films were fabricated on p-type and n-type Si(100) substrates by microwave plasma chemical vapour deposition. Tri-methylborate vapour was introduced to the CH 4-CO 2 gas mixtures as a dopant source. Secondary ion mass spectroscopy (SIMS), Raman and CL spectroscopy, and scanning electron microscopy analysis were performed on the films. The depth profile of SIMS showed that boron was uniformly doped into the diamond film, even at a depth of 6 μ. Boron was found to have a significant effect on both the morphology and the cathodoluminescence of the deposited films. The surface morphology changed from well-defined facets to ball-like features with increasing gas phase dopant concentration. To obtain doped diamond films of good quality, it is necessary to lower the carbon concentration by decreasing the flow rate of CH 4 during the depostion process. The cathodoluminescence of diamond films was investigated in the range 1.8–4.0 eV. The emission peak intensity of CL spectra at 2.3–2.4 eV was found to increase with increasing dopant concentration in the gas phase. The luminescence is explained by donor-acceptor pair recombination, where the acceptor is substitutional boron. This result indicates that boron atoms can be successfully doped into substitutional sites of the diamond structure.

Relationship of progesterone to early pregnancy loss in mares

Exogenous progestins are often given to pregnant mares but many questions remain unanswered as to the relationship between concentrations of progesterone and embryo survival. Thus, embryos were collected 7 days after ovulation and transferred into either ovarian-intact recipients (I,n=15) or ovariectomized recipients which were given 100 mg progesterone (L,n=15) or 1,500 mg progesterone (H,n=15) daily. Concentrations of progesterone were determined in all mares from days 0 to 13. Recipients were examined for pregnancy with ultrasonography during days 11 through 25. Between days 28 and 100, twelve ovarian-intact, pregnant recipients were monitored for follicular and luteal changes and bled for determination of progesterone concentrations for 4 days at 2-week intervals. Twelve ovariectomized pregnant recipients were taken off injectable progesterone days 25-30 and pregnancy maintained to day 100 with an oral progestin, altrenogest. Concentrations of progesterone in these mares were determined every 3 days. Progesterone treatment had no effect on maintenance of pregnancy to day 100 or size of embryonic vesicle (P>0.05). Levels of progesterone during days 1 to 13 were 1.3 to 3.0 ng/ml, >25 ng/ml and 7 to 9 ng/ml for groups L, H and I, respectively. Concentrations of endogenous progesterone in ovariectomized pregnant mares became >1 ng/ml by day 91 of gestation indicating placental progesterone secretion. Increased concentrations of progesterone from days 60 to 100, seen in ovarian-intact, pregnant mares, were primarily due to secretions from corpora lutea. There was, in fact, a correlation between the number of 2°CL and progesterone level (r2=0.74). Initial formation of secondary CL's (2°CL) occurred from 28 to 51 days, with peak formation of 2°CL on days 55 to 70 of gestation.

Epithelial Secretion Driven by Anions Other Than Chloride

Exocrine glands commonly secrete salt using Na+-K+-2Cl- cotransporters to drive secondary active Cl- transport;this process is blocked by furosemide. However, secretion in some glands depends on furosemide-insensitive mechanisms. Some use a Na+-H+ exchanger to transport HCO3-;others may transport HCO3- and HPO24-.

Chlorine initiated photooxidation studies of hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs): Results for HCFC‐22 (CHClF2); HFC‐41 (CH3F); HCFC‐124 (CClFHCF3); HFC‐125 (CF3CHF2); HFC‐134a (CF3CH2F); HCFC‐142b (CClF2CH3); and HFC‐152a (CHF2CH3)

AbstractData on the tropospheric degradation of proposed substitutes for ozone depleting CFCs were obtained by conducting photochemical oxidation studies of HCFCs and HFCs using long path Fourier transform infrared spectroscopy. The hydrogen abstraction reactions were initiated using Cl radicals rather than OH radicals because of the rather unreactive nature of the compounds. The experimental product yields at T = 25 ± 3°C and 700 Torr of dry air were: CHClF2 (1.11 ± 0.06 C(O)F2); CClFHCF3 (1.00 ± 0.04 CF3C(O)F); CF3CHF2 (1.09 ± 0.05 C(O)F2); CClF2CH3 (0.98 ± 0.03 C(O)F2); CHF2CH3 (1.00 ± 0.05 C(O)F2); CF3CH2F (0.16 ± 0.03 CF3CF(O), and 0.83 ± 0.22 HFC(O)), where all standard deviations are 2σ. For each compound, the critical step in determining the oxidation products was the decomposition of a halogenated alkoxy radical. For HCFC‐22 and HCFC‐124, the major alkoxy radical decomposition route was Cl elimination. The HFC‐125 product data were consistent with CC cleavage of a two carbon alkoxy radical as the major decomposition route whereas both CC cleavage and H abstraction by O2 were significant contributors to the decomposition of the HFC‐134a alkoxy radical. Secondary Cl reactions in the HCFC‐142b and HFC‐152a experiments prevented an unambiguous determination of the decomposition modes; the data are consistent with both CC bond scission and Cl reactions with halogenated aldehydes producing the oxidation product C(O)F2. With the exception of the HFC‐134a and HFC‐125 data, the proposed mechanisms can account for the major oxidation products. For HFC‐134a and HFC‐125, a number of product bands could not be identified. The bands are likely due to products from reactions involving the CF3O2 radical. © John Wiley &amp; Sons, Inc.

Coverage dependent structural changes during chlorine adsorption on Ag{110}

The adsorption of Cl2 on Ag{110} at room temperature has been studied using angle-resolved static mode secondary ion mass spectrometry (SIMS), Auger spectroscopy, and LEED. The system has been examined over a coverage range from near zero to the p(2×1) overlayer structure observed by LEED. This structure could be produced by exposing the Ag{110} crystal to 2.5 L of Cl2. The Cl LMM Auger spectra exhibited a distinct change in shape at about 1.0 L exposure which is attributed to a change in the electronic structure of the Ag–Cl bond. In addition, the SIMS Cl− secondary ion yield deviated at this exposure from the expected exponential dependence on work function predicted by theory. An analysis of the secondary Cl− ion kinetic energy distributions, and the polar and azimuthal angle distributions also suggests that the Cl atom is highly charged in the limit of zero coverage with an extended Ag–Cl bond length over that of bulk AgCl. As the coverage approaches the 1.0 L Cl2 exposure point, however, there is significant weakening of surface dipoles due to adlayer interactions. This depolarization appears to be sufficient to allow significant contraction of the Ag–Cl bond length, such that the Cl atom may actually fall into the valley of the {110} surface. A submonolayer Cs overlayer appears to stabilize the negatively charged Cl adatoms, inhibiting the changes observed on the undoped Ag{110} surface. It is suggested that adlayer interactions which influence the formation of ordered overlayer structures mask important electronic and structural features of adsorbates which may only be observed in the single atom limit.

ChemInform Abstract: THE STRUCTURE OF PENTACHLOROCYCLOPENTADIENYLPHENYLMERCURY(II) IN THE SOLID STATE AND IN SOLUTION: THE EFFECT OF X‐RAY ABSORPTION AND CRYSTAL DECAY ON MOLECULAR GEOMETRY PARAMETERS

AbstractDie Titelverbindung kristallisiert inder RG P212121 mit Z=4.

The structure of pentachlorocyclopentadienylphenylmercury(II) in the solid state and in solution; the effect of X-ray absorption and crystal decay on molecular geometry parameters

The structure of pentachlorocyclopentadienylphenylmercury(II), Hg(C5Cl5)Ph, has been determined by single-crystal X-ray diffraction. The cyclopentadienyl ring is σ bonded, and the ring and the vinylic chlorine atoms are essentially coplanar. The structure provides no evidence for secondary Cl→Hg bonding. The 13C n.m.r. spectrum shows that, in solution, the cyclopentadienyl ring is fluxional; the sequence of mobilities is Hg(C5H5)2 > Hg(C5H5)Cl ∼ Hg(C5Cl5)Ph > Hg(C5Me5)2.

Vibrational analysis of 2,3-dichlorobutanes

Using intensity changes from liquid to solid for meso- and racemic-2,3-dichlorobutanes, and preliminary normal mode calculations based on a force field for secondary chlorides, we have been able to identify the bands associated with the trans and gauche conformers of these molecules and thereby to refine a force field for secondary Cl atoms on vicinal C atoms. This has permitted assignment of the S HCl, as well as S HH and S HH′, CCl stretch modes in such molecules.