The tert-butylaminomethyl(mesityl)phosphinic acid ester and formation of its zinc dichloride complex: syntheses and characterization

Michael Lutter; Lukas M. Stratmann; Klaus Jurkschat

doi:10.1515/mgmc-2018-0014

Artikel Open Access

The tert-butylaminomethyl(mesityl)phosphinic acid ester and formation of its zinc dichloride complex: syntheses and characterization

Michael Lutter , Lukas M. Stratmann und Klaus Jurkschat

Veröffentlicht/Copyright: 22. Mai 2018

Veröffentlicht von

Veröffentlichen auch Sie bei De Gruyter Brill

Manuskript einreichen Informationen für Autor*innen Erkunden Sie dieses Fachgebiet

Aus der Zeitschrift Main Group Metal Chemistry Band 41 Heft 3-4

Abstract

The syntheses and structures of tert-butylaminomethyl(mesityl)phosphinic acid ethyl ester 2 and its zinc dichloride complex 3 are reported. In the solid state, both compounds are dimeric via hydrogen bridges. In the complex 3, the phosphinic acid ester 2 coordinates the zinc dichloride diastereoselectively.

Keywords: chelate ligand; diastereoselectivity; phosphinic acid ester; phosphorus; zinc

Introduction

Diorganophosphinic acids R₂PO₂H (R=alkyl, aryl) are a fundamental class of phosphorus compounds. Together with their esters R₂PO₂R′ and the corresponding anions R₂PO₂⁻ they are rather popular phosphorus-based ligands in both main group and transition metal chemistry. The structural diversity of their metal complexes with a total number of more than 500 solid state structures has recently been reviewed (Carson et al., 2017). To the best of our knowledge, unsymmetrically substituted alkyl(aryl)phosphinic acids and their corresponding derivatives (Korpiun et al., 1968; Onyido et al., 2005) as well as functionally substituted compounds have also received increased interest (Maier, 1992; Kaboudin et al., 2006; Demkowicz et al., 2016). Metal complexes with ligands containing phosphinic acid moieties have been reported as well (Lukeš et al., 2001; Cao et al., 2011; Ševčík et al., 2014). Herein, we present an organoaminomethyl(aryl)phosphinic acid ester and demonstrate its behavior as a chelate ligand towards zinc dichloride.

Results and discussion

The tert-butylaminomethyl(mesityl)phosphinic acid ethyl ester tert-Bu(H)NCH₂(2,4,6-Me₃C₆H₂)P(O)OEt, 2, was obtained as its racemate through the amination reaction of compound 1 with an excess of tert-butylamine according to Equation 1.

(1)

The reaction was performed under elevated pressure at 65°C in a teflon-sealed tube. In the course of the reaction, the precipitated white solid was identified by means of the melting point as tert-butylammonium iodide (220°C, lit. 218–220°C (Herrschaft and Hartl, 1989). After a reaction time of 96 h, the conversion was complete and the reaction mixture was purified by performing acid base extraction. Compound 2 was obtained as a white solid material with a melting point of 67°C. A ³¹P{¹H} NMR spectrum of its solution in CDCl₃ showed a singlet resonance at δ 44.6 ppm that was low field shifted as compared with the signal of compound 1 [δ 38.0 ppm, CDCl₃ (Lutter and Jurkschat, 2018)]. A ¹H NMR spectrum revealed the characteristic singlet resonance of the tert-butyl protons at δ 0.89 ppm. An electrospray ionization (ESI) mass spectrum showed three mass clusters which were assigned to [2 2+Na]⁺ (m/z=617.3), [2+Na]⁺ (m/z=320.1) and [2+H]⁺ (m/z=298.1). From its solution in acetone, colorless block-shaped crystals of compound 2 were obtained; the compound crystallized in the monoclinic space group P2₁/n with four molecules in the asymmetric unit (Figure 1). Hydrogen bond distances and angles are given in the Figure caption. Crystallographic data are given in Table 1.

Figure 1:

The displacement ellipsoid (30% probability level) plot and the numbering scheme of the dimeric structure of compound 2 in the crystal.

C-H hydrogen atoms are omitted. Hydrogen bond distance [Å] and angle [°]: N(1)-H(1)···O(1A) 3.001(3), 170(3). Symmetry code: (A) 1-x, 1-y, 1-z.

Table 1:

Crystallographic data for compounds 2 and 3.

	2	3
Empirical formula	C₁₆H₂₈NO₂P	C₁₆H₂₈Cl₂NO₂PZn
Formula mass [g·mol⁻¹]	297.36	433.63
T [K]	173(2)	173(2)
λ [Å]	0.71073	1.54178
Crystal system	Monoclinic	Monoclinic
Space group	P2₁/n	P2₁/c
a [Å]	10.6794 (12)	11.9168 (10)
b [Å]	11.9199 (13)	17.6511(14)
c [Å]	14.0925 (16)	19.9614 (18)
α [°]	90	90
β [°]	105.742 (12)	102.971 (9)
γ [°]	90	90
V [Å³]	1726.7 (3)	4091.6 (6)
Z	4	8
ρ_calcd.[g·cm⁻³]	1.144	1.408
μ [mm⁻¹]	0.161	4.866
F(000)	648	1808
Crystal size [mm]	0.220·0.160·0.130	0.160·0.120·0.030
θ range [°]	2.617–27.499	3.381–68.981
Index ranges	−13≤h≤13	−14≤h≤13
	−15≤k≤15	−20≤k≤21
	−17≤l≤18	−19≤l≤24
No. of reflections collected	14583	29972
No. of independent reflections/R_int	3888/0.0769	7611/0.0637
Completeness of θ_max [%]	99.9	100.0
Data/Restrains/parameters	3888/1/192	7611/2/437
GoF(F²)	0.927	1.551
R₁(F) [I>2σ(I)]	0.0614	0.0635
wR₂(F²) (all data)	0.1615	0.1953
Largest difference peak/hole [eÅ⁻³]	0.253/−0.362	1.561/−1.090

There exists a hydrogen bond (N1-H1···O1 3.001(3) Å, 170(3)°) between the PO and NH functional groups connecting two molecules. In the graph set analysis according to Etter and Bernstein (Bernstein et al., 1990, 1995a,b; Etter, 1990, 1991; Etter et al., 1990; Bernstein, 1991) the unitary elemental graph set is N1=R22(10), which is a ten-membered ring motif. In order to investigate the properties of compound 2 as a chelating ligand, the latter was reacted with zinc chloride in acetone according to Equation 2.

(2)

After the slow evaporation of the solvent, some colorless plate-shaped crystals of compound 3 were obtained. The washed (iso-hexane) and dried crystalline material of compound 3 was used for the acquisition of all analytical data.

A ³¹P{¹H} NMR spectrum (CDCl₃) showed one broad singlet resonance at δ 54.2 ppm (ν_1/2=78.6 Hz), which is low field shifted (9.6 ppm) as compared with the signal of compound 2. The line width of the signal likely indicates the kinetic lability of the complex 3 in solution and an equilibrium 2+ZnCl₂⇌3, which is on the onset of becoming slow on the NMR time scale. Alternatively, an epimerization induced by the rupture of either the P=O→Zn or N→Zn coordination could also account for the broadening of the ³¹P NMR resonance. However, this was not investigated in further detail. A ¹H NMR spectrum showed an ABX pattern for the PCH₂N methylene protons at δ 3.13/3.39 ppm (J_AB=14.8 Hz, J_AX=9.5 Hz, J_BX=6.4 Hz).

An ESI mass spectrum (positive mode) showed four mass peaks at m/z=320.17, 298.19, 213.10, and 185.07, which are assigned to the cationic species [2+Na]⁺, [2+H]⁺, [MesPH(O)(OEt)+H]⁺, and [MesP(OH)₂+H]⁺, respectively. The absence of the mass peak of the zinc complex 3 indicates that a positively charged zinc complex is not stable under the experimental ESI MS conditions employed.

From its solution in acetone, compound 3 precipitated as colorless plate-shaped crystals. The compound crystallized in the monoclinic space group P2₁/c with eight molecules in the asymmetric unit (Figure 2). The hydrogen bond distances and angles are given in the figure caption. Crystallographic data are given in Table 1.

Figure 2:

The displacement ellipsoid (30% probability level) plot and the numbering scheme of the dimeric structure of compound 3 in the crystal.

The C-H hydrogen atoms are omitted. Selected interatomic distances [Å]: Zn(1)-Cl(1) 2.2417(12), Zn(1)-Cl(2) 2.2035(13), Zn(1)-O(1) 2.002(3), Zn(1)-N(1) 2.113(3), Zn(2)-Cl(3) 2.2346(12), Zn(2)-Cl(4) 2.2033(13), Zn(2)-O(3) 2.017(3), Zn(2)-N(2) 2.105(3). Selected interatomic angles [°]: Cl(1)-Zn(1)-Cl(2) 116.95(5), Cl(1)-Zn(1)-N(1) 107.64(11), Cl(1)-Zn(1)-O(1) 107.50(10), Cl(2)-Zn(1)-N(1) 121.71(11), Cl(2)-Zn(1)-O(1) 111.14(10), N(1)-Zn(1)-O(1) 87.44(13), Cl(3)-Zn(2)-Cl(4) 116.18(5), Cl(3)-Zn(2)-N(2) 110.34(11), Cl(3)-Zn(2)-O(3) 110.42(10), Cl(4)-Zn(2)-N(2) 119.88(11), Cl(4)-Zn(2)-O(3) 108.44(11), N(2)-Zn(2)-O(3) 87.66(14). Hydrogen bond distances [Å] and angles [°]: N(1)-H(1)···Cl3 3.502(4), 173(6); N(2)-H(2)···Cl1 3.470(4), 171(5).

The Zn(1) and Zn(2) atoms are four-coordinated by Cl(1), Cl(2), O(1) and N(1), and Cl(3), Cl(4), O(3) and N(2), respectively, at distances of 2.2417(12), 2.2035(13), 2.002(3), and 2.113(3) Å, respectively, and 2.2346(12), 2.2033(13), 2.017(3) and 2.105(3) Å, respectively. The Cl(1) and Cl(3) atoms are involved in the hydrogen bonds (N1-H1···Cl3 3.502(4), N2-H2···Cl1 3.469(4) Å). Consequently, the Zn(1)-Cl(1) and Zn(2)-Cl(3) distances are slightly longer than the Zn(2)-Cl(2) and Zn(2)-Cl(4) distances. The zinc atom exhibits a distorted tetrahedral environment with angles ranging between 121.71(11)° (Cl2-Zn1-N1) and 87.44(13)° (N1-Zn1-O1).

The graph set analysis of compound 3 gives two finite patterns on the unitary elemental level (N₁=DD). The pattern on the binary elemental level is an eight-membered ring and can be described with N2(a, b)=R22(8). Considering this eight-membered ring, the Cl(2) and Cl(4) atoms are trans, as are the five-membered Zn(1)-N(1)-C(10)-P(1)-O(1) and Zn(2)-N(2)-C(60)-P(2)-O(2) chelate rings.

Conclusion

When coordinated with the zinc dichloride, the nitrogen atom of tert-butylaminomethyl(mesityl)phosphinic acid ethyl ester 2 is a stereogenic center, in addition to the one at the phosphorus atom. This means that two diastereomers are possible for the resulting zinc dichloride complex 3. However, apparently, the complexation proceeds diastereoselectively. Only one diastereomer was observed in the solid state. Although this has been established only for the single crystal actually measured, it is rather likely to hold also for the bulk material. The diastereomer with the tert-butyl substituents in cis-position should be less favored. This phenomenon needs to be evaluated by further experiments as well as DFT calculations. Nevertheless, the results demonstrate, to some extent, the high potential the title compound and related derivatives hold for such stereoselective reactions. In addition, the N-H function in both the ester 2 and the zinc dichloride complex 3 is involved in the hydrogen bridges and creates supramolecular structures.

Experimental

Crystallography

Intensity data for compound 2 were collected on an XcaliburS CCD diffractometer (Oxford Diffraction, Oxford, England) using Mo-Kα radiation at 173(1) K with an Oxford Cryostream. The intensity data for compound 3 were collected on an APEX-II CCD diffractometer (Bruker Corporation, Billerica, MA, USA) using Cu-Kα radiation at 100 K.

The structures were solved with direct methods using SHELXS-97 (compound 2) or SHELXS-2014/7 (compound 3) (Sheldrick, 2008, 2015) and refinements were carried out against F2 by using SHELXL-2014/7 (Sheldrick, 2008, 2015). The C-H hydrogen atoms were positioned with idealized geometry and refined using a riding model. All non-hydrogen atoms were refined using anisotropic displacement parameters. The NH protons of all compounds were located in the difference Fourier map and refined freely; the N-H distances were restrained to a fix value.

CCDC-1831583 (2) and CCDC-1831584 (3) contain the supplementary crystallographic data for this paper. This data can be obtained free of charge from The Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif. For the decimal rounding of numerical parameters and su values, the rules of IUCr have been employed (Clegg, 2003). All Figures were generated using ORTEP III (Farrugia, 1997; Farrugia, 2012) visualization software. The graph sets were calculated using cthe alculation routine of Mercury (Macrae et al., 2006, 2008).

General

Solvents, including NMR solvents, were purified by distillation from the appropriate drying agents under argon and stored over molecular sieves. The NMR spectra were recorded at room temperature on a Bruker AV DPX 300. NMR chemical shifts were given in ppm and were referenced to Me₄Si (¹H, ¹³C) (using residual solvent signal: CDCl₃¹H 7.27 ppm, ¹³C 77.0 ppm) and H₃PO₄ (85%, ³¹P). Elemental analyses were performed on a LECO-CHNS-932 analyzer (LECO Corporation, St. Joseph, MI, USA). The samples were weighted at air. The uncorrected melting points were measured on a Büchi M-560 (Büchi Labortechnik GmbH, Essen, Germany). The electrospray mass spectra were recorded with a Thermoquest-Finnigan instrument (Scientific Instrument Services, Ringoes, NJ, USA). The concentration was 0.1 mg/mL with a flow rate of 10 μL/min. The experimental isotopic pattern matched the theoretical ones. IR spectra (cm⁻¹) were measured on a Perkin Elmer Spectrum Two (ATR, PerkinElmer, Inc., Waltham, MA, USA). The synthesis of compound 1 has already been published. (Lutter and Jurkschat, 2018). The tert-butyl amine (98%) was purchased (abcr GmbH, Karlsruhe, Germany). The latter was dried (CaH₂) and distilled prior before use. The zinc chloride (97%) was purchased (abcr GmbH, Karlsruhe, Germany) and used without further purification.

N-(tert-butyl)aminomethyl(mesityl)phosphinic acid ethyl ester (2)

A stirring solution of iodomethylmesitylphosphinic acid ethylester (1) (3.520 g, 10.0 mmol) in freshly distilled tert-butyl amine (10.5 mL, 100.0 mmol) was heated (65°C) for 96 h under pressure. The resulting solid was filtered, washed with cold iso-hexane, dried and identified as tert-butylammoninium iodide by means of the melting point (220°C). The volatiles of the filtrate were removed under reduced pressure. The residue was dissolved in dichloromethane (10 mL), acidified with diluted hydrochloric acid (10 mL, 1 m), and extracted with water (3×10 mL). The combined aqueous phases were treated with a diluted sodium hydroxide solution (1 m) to pH >10 and extracted with dichloromethane (3×10 mL). After drying the combined organic phases over magnesium sulphate and performing filtration, the volatiles of the resulting solution were removed under reduced pressure. Compound 2 (1.930 g, 6.5 mmol, 65%) was obtained as a colorless block-shaped crystalline solid with a melting point of 67°C.

¹H NMR: (300.13 MHz, CDCl₃, 298 K, 16 scans): δ 6.76 (d, ⁴J(¹H-³¹P)=3.7 Hz, 2H, C_mH), 4.15–4.02 (complex pattern, 1H, CH₂CH₃), 3.89–3.76 (complex pattern, 1H, CH₂CH₃), 3.02-2.85 (complex pattern, 2H, PCH₂N), 2.51 (s, 6H, C_oCH₃), 2.14 (s, 3H, C_pCH₃), 1.20 (t, ³J(¹H-¹H)=7.1 Hz, 3H, CH₂CH₃), 0.89 (s, 9H, C(CH₃)₃). ¹³C{¹H} NMR: (75.48 MHz, CDCl₃, 298 K, 640 scans): δ 143.1 (d, ²J(¹³C-³¹P)=11.2 Hz, C_o), 141.2 (d, ⁴J(¹³C-³¹P)=2.8 Hz, C_p), 130.3 (d, ³J(¹³C-³¹P)=12.7 Hz, C_m), 123.6 (d, ¹J(¹³C-³¹P)=120.4 Hz, C_i), 60.0 (d, ²J(¹³C-³¹P)=6.5 Hz, CH₂CH₃), 50.3 (d, ³J(¹³C-³¹P)=14.6 Hz, C(CH₃)₃), 43.0 (d, ¹J(¹³C-³¹P)=110.1 Hz, PCH₂N), 28.1 (s, C(CH₃)₃), 22.9 (d, ³J(¹³C-³¹P)=2.3 Hz, ortho-C_oCH₃), 20.6 (d, ⁵J(¹³C-³¹P)=0.9 Hz, para-C_pCH₃), 16.1 (d, ³J(¹³C-³¹P)=6.4 Hz, CH₂CH₃). ³¹P{¹H} NMR: (121.50 MHz, CDCl₃, 298 K, 128 scans): δ=44.6 (s, ¹J(³¹P-¹³C)=120.3 Hz, ¹J(³¹P-¹³C)=110.1 Hz). Elemental analysis: calculated (found) for C₁₆H₂₈NO₂P 64.6 (64.8)% C, 9.5 (9.3)% H, 4.7 (4.7)% N. ESI MS: (acetonitrile, m/z, positive mode): 617.3 [2 2+Na]⁺, 320.1 [2+Na]⁺, 298.1 [2+H]⁺. IR: (cm⁻¹): ν_N-H 3288, ν_P=O 1212.

N-(tert-butyl)aminomethyl(mesityl)phosphinic acid ethyl ester zinc chloride complex (3)

To a solution of the secondary amine 2 (0.120 g, 0.4 mmol) in acetone (5 mL) zinc chloride (0.550 g, 0.4 mmol) was added. After the slow evaporation of the solvent, the complex 3 was obtained as a colorless plate-shaped crystalline solid (0.164 g, 0.38 mmol, 95%) with a melting point of 180°C (decomposition).

¹H NMR: (300.13 MHz, CDCl₃, 297 K, 16 scans): δ 6.97 (d, ⁴J(¹H-³¹P)=4.5 Hz, 2H, C_mH), 4.34–3.97 (complex pattern, 2H, CH₂CH₃), 3.39 (ABX pattern, ²J(¹H-¹H)=14.8 Hz, ²J(¹H-³¹P)=9.5 Hz, 1H, PCH₂N), 3.13 (ABX pattern, ²J(¹H-¹H)=14.8 Hz, ²J(¹H-³¹P)=6.4 Hz, 1H, PCH₂N), 2.59 (d, ⁴J(¹H-³¹P)=1.2 Hz, 6H, C_oCH₃), 2.32 (s, 3H, C_pCH₃), 1.38 (s, 9H, C(CH₃)₃), 1.36 (t, ³J(¹H-¹H)=7.1 Hz, 3H, CH₂CH₃). ¹³C{¹H} NMR: (75.47 MHz, CDCl₃, 297 K, 640 scans): δ 144.7 (d, ⁴J(¹³C-³¹P)=2.8 Hz, C_p), 144.1 (d, ²J(¹³C-³¹P)=12.7 Hz, C_o), 131.5 (d, ³J(¹³C-³¹P)=14.1 Hz, C_m), 118.5 (d, ¹J(¹³C-³¹P)=131.4 Hz, C_i), 63.6 (d, ²J(¹³C-³¹P)=6.7 Hz, CH₂CH₃), 56.5 (d, ³J(¹³C-³¹P)=9.9 Hz, C(CH₃)₃), 42.0 (d, ¹J(¹³C-³¹P)=102.2 Hz, PCH₂N), 27.9 (s, C(CH₃)₃), 23.3 (d, ³J(¹³C-³¹P)=3.0 Hz, CC_oH₃), 21.2 (d, ⁵J(¹³C-³¹P)=0.8 Hz, C_pCH₃), 16.1 (d, ³J(¹³C-³¹P)=6.7 Hz, CH₂CH₃). ³¹P{¹H} NMR: (121.50 MHz, CDCl₃, 297 K, 128 scans): δ=54.2 (s, ν_1/2=78.6 Hz). Elemental analysis: calculated (material from 1st synthesis found, material from 2nd synthesis found) for C₁₆H₂₈Cl₂NO₂PZn 44.3 (43.2, 43.5)% C, 6.5 (6.5, 6.5)% H, 3.2 (3.1, 3.1)% N. ESI MS: (material from 2nd synthesis, acetonitrile+water 1:1+0.1% trifluoro acetic acid, m/z, positive mode): 320.17 [2+Na]⁺, 298.19 [2+H]⁺, 213.10 [MesPH(O)(OEt)+H]⁺, 185.07 [MesP(OH)₂+H]⁺. ESI MS: (material from 2nd synthesis, acetonitrile, m/z, positive mode): 595.38 [2 2+H]⁺, 298.19 [2+H]⁺. IR: (cm⁻¹): ν_N-H 3197, ν_P=O 1150.

References

Bernstein, J. Polymorphism of L-glutamic acid: decoding the α-β phase relationship via graph-set analysis. Acta Cryst.1991, B47, 1004–1010.10.1107/S0108768191009345Suche in Google Scholar

Bernstein, J.; Etter, M. C.; MacDonald, J. C. Decoding hydrogen-bond patterns. The case of iminodiacetic acid. J. Chem. Soc., Perkin Trans. 21990, 5, 695.10.1039/p29900000695Suche in Google Scholar

Bernstein, J.; Davis, R. E.; Shimoni, L.; Chang, N.-L. Patterns in hydrogen bonding: functionality and graph set analysis in crystals. Angew. Chem. Int. Ed.1995a, 34, 1555–1573.10.1002/anie.199515551Suche in Google Scholar

Bernstein, J.; Shimoni, L.; Davis, R. E.; Chang, N.-L. Muster aus H-Brücken: ihre Funktionalität und ihre graphentheoretische Analyse in Kristallen. Angew. Chem.1995b, 107, 1689–1708.10.1002/ange.19951071505Suche in Google Scholar

Cao, Z.; Zhang, Y.; Song, P.; Cai, Y.; Guo, Q.; Fang, Z.; Peng, M. A novel zinc chelate complex containing both phosphorus and nitrogen for improving the flame retardancy of low density polyethylene. J. Anal. Appl. Pyrolysis2011, 92, 339–346.10.1016/j.jaap.2011.07.007Suche in Google Scholar

Carson, I.; Healy, M. R.; Doidge, E. D.; Love, J. B.; Morrison, C. A.; Tasker, P. A. Metal-binding motifs of alkyl and aryl phosphinates; versatile mono and polynucleating ligands. Coord. Chem. Rev.2017, 335, 150–171.10.1016/j.ccr.2016.11.018Suche in Google Scholar

Clegg, W. Some guidelines for publishing SHELXL-generated CIF results in Acta Crystallographica. decimal rounding. Acta Cryst.2003, E59, e2-e5.10.1107/S1600536802023279Suche in Google Scholar

Demkowicz, S.; Rachon, J.; Dasko, M.; Kozak, W. Selected organophosphorus compounds with biological activity. Applications in medicine. RSC Adv.2016, 6, 7101–7112.10.1039/C5RA25446ASuche in Google Scholar

Etter, M. C. Encoding and decoding hydrogen-bond patterns of organic compounds. Acc. Chem. Res.1990, 23, 120–126.10.1021/ar00172a005Suche in Google Scholar

Etter, M. C. Hydrogen bonds as design elements in organic chemistry. J. Phys. Chem.1991, 95, 4601–4610.10.1021/j100165a007Suche in Google Scholar

Etter, M. C.; MacDonald, J. C.; Bernstein, J. Graph-set analysis of hydrogen-bond patterns in organic crystals. Acta Cryst.1990, B46, 256–262.10.1107/S0108768189012929Suche in Google Scholar PubMed

Farrugia, L. J. ORTEP -3 for windows – a version of ORTEP-III with a graphical user interface (GUI). J. Appl. Cryst.1997, 30, 565.10.1107/S0021889897003117Suche in Google Scholar

Farrugia, L. J. WinGX and ORTEP for windows: an update. J. Appl. Cryst.2012, 45, 849–854.10.1107/S0021889812029111Suche in Google Scholar

Herrschaft, G.; Hartl, H. Das isomerenpaar tert-butylammoniumiodid und tetramethylammoniumiodid. Acta Cryst.1989, C45, 1021–1024.10.1107/S0108270189000065Suche in Google Scholar

Kaboudin, B.; Haghighat, H.; Yokomatsu, T. A novel method for the separation of bis(alpha-hydroxyalkyl)phosphinic acid diastereoisomers via formation of novel cyclic phosphinic acids. J. Org. Chem.2006, 71, 6604–6606.10.1021/jo060547hSuche in Google Scholar PubMed

Korpiun, O.; Lewis, R. A.; Chickos, J.; Mislow, K. Synthesis and absolute configuration of optically active phosphine oxides and phosphinates. J. Am. Chem. Soc.1968, 90, 4842–4846.10.1021/ja01020a017Suche in Google Scholar

Lukeš, I.; Kotek, J.; Vojtı́šek, P.; Hermann, P. Complexes of tetraazacycles bearing methylphosphinic/phosphonic acid pendant arms with copper(II), zinc(II) and lanthanides(III). A comparison with their acetic acid analogues. Coord. Chem. Rev.2001, 216–217, 287–312.10.1016/S0010-8545(01)00336-8Suche in Google Scholar

Lutter, M.; Jurkschat, K. Aryl(dimethylaminomethyl)phosphinic acid esters. syntheses, structures, and reactions with halogen hydrogen acids, tin halides and trimethyl halosilanes. Eur. J. Inorg. Chem.2018, manuscript accepted.10.1002/ejic.201800343Suche in Google Scholar

Macrae, C. F.; Edgington, P. R.; McCabe, P.; Pidcock, E.; Shields, G. P.; Taylor, R.; Towler, M.; van de Streek, J. Mercury: visualization and analysis of crystal structures. J. Appl. Cryst.2006, 39, 453–457.10.1107/S002188980600731XSuche in Google Scholar

Macrae, C. F.; Bruno, I. J.; Chisholm, J. A.; Edgington, P. R.; McCabe, P.; Pidcock, E.; Rodriguez-Monge, L.; Taylor, R.; van de Streek, J.; Wood, P. A. Mercury CSD 2.0 – new features for the visualization and investigation of crystal structures. J. Appl. Cryst.2008, 41, 466–470.10.1107/S0021889807067908Suche in Google Scholar

Maier, L. Organic phosphorus compounds 101. Preparation and physical properties of bis(aminoalkyl)phosphinic acids. Phosphorus, Sulfur Silicon Relat. Elem.1992, 66, 67–72.10.1080/10426509208038332Suche in Google Scholar

Onyido, I.; Albright, K.; Buncel, E. Catalysis of the ethanolysis of aryl methyl phenyl phosphinate esters by alkali metal ions: transition state structures for uncatalyzed and metal ion-catalyzed reactions. Org. Biomol. Chem.2005, 3, 1468–1475.10.1039/b501537eSuche in Google Scholar PubMed

Ševčík, R.; Vaněk, J.; Lubal, P.; Kotková, Z.; Kotek, J.; Hermann, P. Formation and dissociation kinetics of copper(II) complexes with tetraphosphorus acid DOTA analogs. Polyhedron2014, 67, 449–455.10.1016/j.poly.2013.09.024Suche in Google Scholar

Sheldrick, G. A short history of SHELX. Acta Cryst.2008, A64, 112–122.10.1107/S0108767307043930Suche in Google Scholar PubMed

Sheldrick, G. M. Crystal structure refinement with SHELXL. Acta Cryst.2015, C71, 3–8.10.1107/S2053229614024218Suche in Google Scholar

Received: 2018-03-24

Accepted: 2018-04-25

Published Online: 2018-05-22

Published in Print: 2018-08-28

This article is distributed under the terms of the Creative Commons Attribution Non-Commercial License, which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Artikel in diesem Heft

https://doi.org/10.1515/mgmc-2018-0014

Schlagwörter für diesen Artikel

chelate ligand; diastereoselectivity; phosphinic acid ester; phosphorus; zinc

Creative Commons

BY-NC-ND 3.0