195Pt and 15N NMR data in square planar Platinum(II) complexes of the type [Pt(NH3)aXb]n (Xb = combination of halides): "NMR effective molecular radius" of coordinated ammonia

2020 ◽  
Author(s):  
Michele Benedetti ◽  
Federica De Castro ◽  
Paride Papadia ◽  
Daniela Antonucci ◽  
Francesco Paolo Fanizzi
Keyword(s):  
15N Nmr ◽  
Nmr Data ◽  
Square Planar ◽  
Molecular Radius

Anwendung der 15N-NMR-Spektroskopie zur Charakterisierung reaktiver, koordinativ ungesättigter Zinn-, Bleiund Phosphor-Stickstoff-Verbindungen / Application of 15N-NMR Spectroscopy to the Characterization of Reactive, Coordinatively Unsaturated Tin-, Lead- and Phosphorus-Nitrogen Compounds

1987 ◽  
Vol 42 (12) ◽  
pp. 1515-1519 ◽  
Author(s):  
Carin Stader ◽  
Bernd Wrackmeyer
Keyword(s):  
Nmr Spectra ◽  
Pulse Sequence ◽  
Coupling Constants ◽  
Spin Coupling ◽  
15N Nmr ◽  
Nmr Data ◽  
15N Nmr Spectroscopy ◽  
Spin Coupling Constants ◽  
Spin Spin Coupling

AbstractThe basic INEPT pulse sequence proved most useful for recording 15N NMR spectra at natural abundance of bis(amino)stannvlenes (1). -plumbylenes (2) and of imino-amino-λ2-phosphanes (3), where the nitrogen atoms carry bulky substituents like Me3Si-, t-Bu-, 2.4.4-trimethyl-2- pentyl-groups (t-Oct-groups) or are part of the 2.2.6.6-tetramethylpiperidinyl group. The sensitiv­ity of this technique is proved by the observation of 117/119Sn or 207Pb satellites owing to spin-spin coupling constants 1J(117/119Sn15N) and 1J(117/119Pb15N), respectively. NMR data of bis[bis(trimethylsilyl)methyl]tin (4) are reported in order to corroborate the arguments for the interpretation of the δ(15N) and 1J(119Sn15N) data. The 15N NMR data of the λ2-phosphanes (3) indicate a bonding situation similar to that in triazenes.

1H, 13C and 15N NMR data for indolo[2,3-b ]quinolines, a novel potent anticancer drug family

2013 ◽  
Vol 51 (9) ◽  
pp. 569-573 ◽  
Author(s):  
E. Bednarek ◽  
J. Sitkowski ◽  
W. Bocian ◽  
W. Łuniewski ◽  
M. Kobylińska ◽  
...  
Keyword(s):  
Anticancer Drug ◽  
15N Nmr ◽  
Nmr Data

Structure elucidation of the dye Acid Red 131: complete 1H, 13C and 15N NMR data assignment

2011 ◽  
Vol 49 (8) ◽  
pp. 523-528 ◽  
Author(s):  
Elisabetta Schievano ◽  
Ileana Menegazzo ◽  
Ester Marotta ◽  
Stefano Mammi
Keyword(s):  
Structure Elucidation ◽  
15N Nmr ◽  
Nmr Data

13C- und 15N-NMR-spektroskopische Untersuchungen einiger Pentacarbonylchrom-Aminophosphan-Komplexe/13C and 15N NMR Spectroscopic Study of Some Pentacarbonylchromium-Aminophosphane Complexes

1989 ◽  
Vol 44 (1) ◽  
pp. 55-62 ◽  
Author(s):  
Bernd Wrackmeyer ◽  
Klaus Schamei ◽  
Max Herberhold
Keyword(s):  
Binuclear Complex ◽  
Nmr Spectra ◽  
15N Nmr ◽  
Amino Groups ◽  
Nmr Parameters ◽  
Nmr Data ◽  
Regular Change ◽  
Nuclear Shielding ◽  
The Relationship ◽  
C Nmr

13C and 15N NMR data are reported for the free aminophosphanes ʹBu3-nP(NH2)n (n = 1 (1), 2 (2)), for the corresponding pentacarbonylchromium complexes (OC)5Cr-P(ʹBu)3-n(NH2)n (n = 1 (3), n = 2 (4), n = 3 (5)), and for other (OC)5Cr-aminophosphane complexes such as (OC)5Cr-P(NMe2)3, (6 ) and a binuclear complex (7) in which the sulfurdiimide derivative ʹBu(NH2)P-NSN-P(NH2)ʹBu serves as the phosphane ligand. Various techniques (e.g. INEPT and reverse two-dimensional (2D) 1H {15N}-experiments) have been used for recarding the 15N NMR spectra at natural abundance. In contrast to suggestions in the literature, the relationship between the 13C NMR parameters for the axial and equatorial CO groups and the σ-donor/π-acceptor properties of the phosphane ligand is not straightforward. The 15N resonances of the (OC)5Cr complexes 3, 4, 6 are shifted to higher frequencies with respect to those of the free ligands, and there is a regular decrease in 15N nuclear shielding in the series of 3, 4, 5. The |1J(31P15N)| values vary between 17 and 65 Hz, the smaller values being observed for the (OC)5Cr complexes. The lack of a regular change in the magnitude of 1J(31P15N) in the series 3, 4, 5 indicates that this parameter is influenced by the nature of both the Cr-P and the P-N bonds as a function of the number of amino groups.

scholarly journals Synthesis, Characterization, and Reaction Studies of Pd(II) Tripeptide Complexes

Molecules ◽  
2021 ◽  
Vol 26 (17) ◽  
pp. 5169
Author(s):  
Lindsey J. Monger ◽  
Dmitrii Razinkov ◽  
Ragnar Bjornsson ◽  
Sigridur G. Suman
Keyword(s):  
Ligand Exchange ◽  
Coordination Mode ◽  
Planar Geometry ◽  
Exchange Reactions ◽  
Aqueous Synthesis ◽  
Ph Values ◽  
Nmr Data ◽  
Square Planar ◽  
Acidic Conditions ◽  
Hydrolysis Of

The aqueous synthesis of Pd(II) complexes with alkylated tripeptides led to the hydrolysis of the peptides at low pH values and mixtures of complexed peptides were formed. A non-aqueous synthetic route allowed the formation and isolation of single products and their characterization. Pd(II) complexes with α-Asp(OR)AlaGly(OR), β-Asp(OR)AlaGly(OR), and TrpAlaGly(OR) (R = H or alkyl) as tri and tetradentate chelates were characterized. The tridentate coordination mode was accompanied by a fourth monodentate ligand that was shown to participate in both ligand exchange reactions and a direct removal to form the tetradentate coordination mode. The tetradentate coordination revealed a rare a hemi labile carbonyl goup coordination mode to Pd(II). Reactivity with small molecules such as ethylene, acids, formate, and episulfide was investigated. Under acidic conditions and in the presence of ethylene; acetaldehyde was formed. The Pd(II) is a soft Lewis acid and thiophilic and the complexes abstract sulfur from episulfide at apparent modest catalytic rates. The complexes adopt a square planar geometry according to a spectroscopic analysis and DFT calculations that were employed to evaluate the most energetically favorable coordination geometry and compared with the observed infrared and NMR data.

Sulphur–nitrogen anions: 14N and 15N NMR investigations of the deprotonation of cyclic sulphur imides and sulphur–ammonia solutions

1992 ◽  
Vol 70 (3) ◽  
pp. 710-718 ◽  
Author(s):  
T. Chivers ◽  
K. J. Schmidt
Keyword(s):  
Nmr Spectroscopy ◽  
Sodium Azide ◽  
Liquid Ammonia ◽  
Molar Ratio ◽  
15N Nmr ◽  
Molar Ratios ◽  
Nmr Data ◽  
Nmr Characterization

The following systems have been investigated by 14N and (or)15N NMR spectroscopy: (a) the deprotonation of S7NH by n-BuLi, (b) solutions of S8, S7NH, 1,3- and 1,4-S6(NH)2, and K2SN2 in liquid ammonia, (c) the reaction of sodium azide with sulphur in hexamethylphosphoramide (HMPA), (d) the reactions of S7NH and S4(NH)4 with potassium amide in liquid ammonia in various molar ratios, and (e) the reaction of (NSCl)3 with potassium amide (1:6 molar ratio) in liquid ammonia. These investigations have provided an NMR characterization of the thermally unstable S7N− (δ15N ca. −324 ppm) and S2N2H− ions (δ14N + 7 and −149 ppm, 1J(14N−1H) 36 Hz, 1J(15N−H) 55 Hz, 2J(15N-15N) 2.2 Hz) in liquid ammonia, demonstrated the existence of S7N−, in addition to SSNSS−, as the major nitrogen-containing ingredient of sulphur–ammonia solutions (SAS), and confirmed the formation of the SSNSS−, but not S7N−, from the reaction of sodium azide and sulphur in HMPA. Consistent with previous chemical investigations, the NMR data show that the S7N− and S2N2H− ions are thermally unstable with respect to the formation of SSNSS− and S3N3−, respectively, in solution. Solutions of S4(NH)4/4KNH2 or (NSCl)3/6KNH2 show the same two 14N or 15N NMR resonances at ca. +97 and −108 ppm as a solution of NSN2− in liquid ammonia. Keywords: sulphur–nitrogen anions, nitrogen NMR, liquid ammonia.

scholarly journals High-resolution NMR studies of structure and dynamics of human ERp27 indicate extensive interdomain flexibility

2013 ◽  
Vol 450 (2) ◽  
pp. 321-332 ◽  
Author(s):  
Nader T. Amin ◽  
A. Katrine Wallis ◽  
Stephen A. Wells ◽  
Michelle L. Rowe ◽  
Richard A. Williamson ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
High Resolution ◽  
Nmr Relaxation ◽  
Full Length ◽  
15N Nmr ◽  
Nmr Studies ◽  
Average Order ◽  
X Ray ◽  
Nmr Data ◽  
High Resolution Nmr

ERp27 (endoplasmic reticulum protein 27.7 kDa) is a homologue of PDI (protein disulfide-isomerase) localized to the endoplasmic reticulum. ERp27 is predicted to consist of two thioredoxin-fold domains homologous with the non-catalytic b and b′ domains of PDI. The structure in solution of the N-terminal b-like domain of ERp27 was solved using high-resolution NMR data. The structure confirms that it has the thioredoxin fold and that ERp27 is a member of the PDI family. 15N-NMR relaxation data were obtained and ModelFree analysis highlighted limited exchange contributions and slow internal motions, and indicated that the domain has an average order parameter S2 of 0.79. Comparison of the single-domain structure determined in the present study with the equivalent domain within full-length ERp27, determined independently by X-ray diffraction, indicated very close agreement. The domain interface inferred from NMR data in solution was much more extensive than that observed in the X-ray structure, suggesting that the domains flex independently and that crystallization selects one specific interdomain orientation. This led us to apply a new rapid method to simulate the flexibility of the full-length protein, establishing that the domains show considerable freedom to flex (tilt and twist) about the interdomain linker, consistent with the NMR data.

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