Thioureido Cymantrene Derivatives: Synthesis and Photochromic

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Thioureido Cymantrene Derivatives: Synthesis and Photochromic Properties Elena S. Kelbysheva,*,† Lyudmila N. Telegina,† Tatyana V. Strelkova,† Mariam G. Ezernitskaya,† Aleksander F. Smol’yakov,†,‡ Yurii A. Borisov,† Boris V. Lokshin,† Elizaveta A. Konstantinova,§ Oleg I. Gromov,∥ Alexander I. Kokorin,⊥ and Nikolay M. Loim†

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A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 28 Vavilov street, GSP-1, Moscow 119991, Russian Federation ‡ Plekhanov Russian University of Economics, Stremyanny per. 36, Moscow 117997, Russian Federation § National Research Center “Kurchatov Institute”, Akademika Kurchatova 1, Moscow 123182, Russian Federation ∥ Chemistry Department, M. V. Lomonosov Moscow State University, Leninskie Gory 1-2, Moscow 119991, Russian Federation ⊥ N. N. Semenov Institute of Chemical Physics RAS, Kosygin st. 4, Moscow 119991, Russian Federation S Supporting Information *

ABSTRACT: Photolysis of thioureido derivatives of cymantrene in solution and solvent-free affords stable six-membered dicarbonyl chelates due to coordination of sulfur of the CS group to manganese. The process is accompanied by a color change and the appearance of new bands at 400 and 500 nm in the UV−vis spectra. In the presence of carbon monoxide, these chelates enter the reverse thermal reaction to give the parent tricarbonyl complexes thus forming photochromic systems. In the air, dicarbonyl chelates are oxidized to form stable dicarbonyl Mn-based radicals, which were isolated, and their structure was proved by electron paramagnetic resonance spectra and density functional theory calculations. The irradiation of these dark violet radicals, in turn, also results in formation of stable photochromic systems. Dicarbonyl olefin chelates were synthesized; upon photolysis of these compounds, stable intramolecular photochromic systems with high quantum yield were obtained. The reverse thermal reaction occurs via dissociative isomerization of the substituent.

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INTRODUCTION Photolysis of cymantrenes (cyclopentadienylmanganese tricarbonyl) attracts attention in view of application in catalysis,1 as a method for controlled dosing of CO for therapeutic goals2 and creation of photochromic systems.3,4 Photochemical CO loss by cymantrene and its derivatives comprises a fundamental method for the synthesis of mono- and binuclear carbonyl complexes of cyclopentadienylmanganese.5−9 It is known that CO loss upon photolysis of substituted cymantrenes results in stabilization of 16e intermediate due to coordination of a donor fragment of a substituent to manganese accompanied by a color change. Upon reverse thermal reaction with CO, photochromic systems with high quantum yield are formed. (Scheme 1).3,4 An increase in a number of functional donor fragments in a substituent expands the possibility for the formation of various chelates and linkage isomerization during irradiation or thermal reactions. In particular, we found that photolysis of bifunctional carbamates and amides of N-allyl-1-cymantrenylalkylamines results in reversible photochromic pairs including six-membered dicarbonyl chelates with a Mn−OC (amide) bond.3b Burkey4 and co-workers found that photolysis of thioamide of 3cymantrenyl-2-pyridylpropionic acid gives a stable related chelate with a Mn−SC (thioamide) bond. In continuation of studies of photochemical reactions of cymantrene derivatives, © XXXX American Chemical Society

Scheme 1. General Background of the Research

in this work, the photolysis of derivatives of N-(1-cymantrenylalkyl)-N′-phenylthioureas was studied.

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RESULTS AND DISCUSSION Cymantrene derivatives containing a thiourea fragment were prepared according to the standard method10 (Scheme 2). Compounds 4−6 were synthesized by the reaction of the Received: March 13, 2019

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DOI: 10.1021/acs.organomet.9b00165 Organometallics XXXX, XXX, XXX−XXX

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Organometallics

from full energies corrected for zero-point vibrational energy. Calculations with account for diffuse functions (6-311+G*) gave the same picture, but the energy difference increased to 12.48 kcal/mol. The introduction of a π-donating allyl group into the thiourea fragment (compounds 5 and 6) expands opportunities for chelation, because it is known that photolysis of cymantrenyl derivatives having an allyl fragment in a substituent results in stable dicarbonyl chelates due to coordination of Mn to CHCH2 group.3b,12 Starting complexes 4−6 have two (MCO) stretches in the IR spectra (symmetric and degenerate). Upon irradiation, these bands gradually disappear, and instead two new bands of approximately equal intensity appear (Table 1). These bands can be assigned to MCO stretches of the Mn(CO)2 fragment (symmetric and asymmetric) in chelates 7−9, where Mn is coordinated to the S atom of the thiourea substituent. This assignment is based on the supposition that the N-coordination is excluded, because ν(NH) at 3368 cm−1 does not change on going from tricarbonyl to dicarbonyl complexes. It is known that olefin-coordinated chelates have the ν(MCO) bands at 1927 and 1910 cm−1;3b,12 these bands are not observed in our case. The band at 1863 cm−1 is present in the IR spectra of all three chelates 7−9; since 7 has no allyl group in the substituent, the band at 1863 cm−1 can be considered as an analytical frequency for S-coordinated dicarbonyl chelates. The coordination of Mn to the S atom is also confirmed by the DFT B3LYP/6-31G*11 calculations (Table 1 and Table S3 Supporting Information). In the absence of air and CO, solutions of chelate 7 is stable for several days. In the presence of CO, chelates 7−9 enter the reverse thermal reaction to give the corresponding tricarbonyl complexes 4−6 (Scheme 3, τ1/2 see Table 1). The IR monitoring of these reactions reveals the isosbestic point indicating the lack of side products (Figure 3). The cycle can be repeated several times. Thus, complexes 4−6 and chelates 7−9 form in solution a reversible intermolecular photochromic system, but a response time is large. The kinetic studies of the thermal transformations of the dicarbonyl chelates 7−9 to the corresponding tricarbonyl complexes 4−6 in the presence of CO in benzene at 24 °C reveal the first-order kinetics with a quality of fit no less than 0.998 (Table 1). Thus, thermal reactions with CO for Scoordinated dicarbonyl chelates follow the dissociative mechanism. The kinetic parameters (reaction rate constant and halfconversion time) for the reactions of chelates 7−9 (Table 1) indicate that the reverse thermal reaction rate depends on the presence of the allyl substituent at the N atom. The estimation of the quantum yield for the phototransformation of 6 in benzene relative to φ 0.8 for the photolysis of [(1-η2-allyloxy-2-pyryd-2ylethyl)-η5-cyclopentadienyl](dicarbonyl)manganese (S)12 gives a value of 0.96. Although complexes 7−9 are stable in the absence of carbon monoxide, the attempt to isolate these complexes gave products 10−12 (Scheme 3) obtained after column chromatography as dark violet powders. The 1H NMR spectrum of 10−12 in deuterobenzene appeared substantially broadened and shifted to a low field up to 10 ppm compared to the spectrum of the parent dicarbonyls 7−9. This spectral picture can be associated with paramagnetic nature of 10−12. The radical nature of these compounds was proved by the electron paramagnetic resonance (EPR) spectra. Typical EPR spectra of compound 12 in deuterated toluene at 77 and 298 K are shown in Figure 4. Mn2+ complexes with

Scheme 2. Synthesis of Compounds 4−6

corresponding cymantrenylamines 1−3 with phenylisothiocyanate. The molecular structure of N-(1-cymantrenylethyl)-N′phenylthiourea (4) was established by an X-ray analysis (Figure S31, Table S2 Supporting Information). Photolysis was performed by irradiation of a solution with a whole spectrum or monochromatic light (λ 365 nm) of a Hg lamp. A solution was placed either into an NMR ampule or IR cell. In the latter case, CO eliminated retained in solution and was able to enter the reverse reaction. Irradiation of solutions studied in benzene, tetrahydrofuran (THF), and CH3CN results in a color change from light yellow to red-orange. The structure of the photolysis products was established from 1H NMR and IR spectra and confirmed by density functional theory (DFT) calculations. The photolysis of compounds 4−6 leads to the changes in the 1 H NMR, IR, and UV−vis spectra. After the photolysis in benzene and THF, two new bands at 400 and 500 nm appear in the UV−vis spectra (Figure 1, Table 1) in accordance with the color change.

Figure 1. UV−Vis spectra of complex 6, chelate 9, and radical 12 in THF.

Photochemical transformations of tricarbonyls 4−6 were monitored by 1H NMR spectroscopy. For example, the photolysis of 5 in deuterobenzene performed in an NMR ampule to 40−50% conversion gives in the 1H NMR spectrum two signal sets: for complex 8 (Scheme 3) and for complex 5 (Figure 2). On going from tricarbonyl complexes to chelates, the signals from the 2,5(α)-protons of the Cp-ring for dicarbonyl chelate are low-field shifted, whereas the signals from the 3,4(β)protons are high-field shifted. In compound 4, there are two donor atoms in the side substituent capable of coordinating to Mn, nitrogen, and sulfur. The formation of 7 (Scheme 3) rather than 7a (Figure S34 Supporting Information) is confirmed by the IR spectra, where the ν(SH) at 2600 cm−1 is absent, and by the DFT B3LYP/631G* calculations.11 The calculations of isomeric dicarbonyl chelates 7 and 7a in the gas phase showed that 7 is by 5.47 kcal/ mol more stable than 7a (Table 1). This value was obtained B

DOI: 10.1021/acs.organomet.9b00165 Organometallics XXXX, XXX, XXX−XXX

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Table 1. Experimental Data on the IR and UV−Vis Spectra of Compounds 4−12, 16, 17, and 19−21 in Benzene, Calculated Energies of Compounds 4−12, 16, and 17, and Kinetic Data of Compounds 7−9, 16, 17, and 20 compound

IR, cm−1

λ, nm (ε)

EG, a.u.

4 7 7a 10 5 8 8a 11 16 6 9 9a 12 17 19 20 21

2019, 1938 1927, 1863

323 (1766) 403 (958), 508 (877)

2005, 1936 2022, 1937 1927, 1862

503 (2272), 629 (867) 334(1177) 390 (1082), 495 (479)

2002, 1934 1967, 1905 2020, 1935 1938, 1856

502 (607), 605 (107) 329 (3586) 332 (1594) 432 (1002), 504 (839)

2005, 1939 1971, 1910 2023, 1938 1927, 1862 2005, 1936

503 (1024), 629 (391) 334 (2613) 332 (1263) 371 (898), 495 (387) 509 (946), 639 (251)

−2540.953 681 −2427.601 680 −2427.591 677 −2427.013 718 −2618.313 312 −2504.958 187 −2504.942 990 −2504.367 703 −2504.959 319 −2657.592 041 −2544.241 569 −2544.228 122 −2543.651 203 −2544.245 021

τ1/2, min

kobs × 104, sec−1

697

0.17 ± 0.003

48

1.94 ± 0.018

248

0.52 ± 0.006

64

1.81 ± 0.025

533

0.22 ± 0.002

205

0.56 ± 0.003

Scheme 3. Combined Scheme of All the Transformations Studied

Figure 3. IR monitoring in the ν(CO) region of the reverse thermal reaction of 9 to 6 in THF. Figure 2. 1H NMR spectra of solution 5 in deuterobenzene: (A) before irradiation, (B) after irradiation (50% conversion of 5 to 8). C

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monomeric radical complexes of 16e dicarbonylcyclopentadienylmanganese containing the thienyl radical (13)13a allows us to conclude that 12 is a radical complex with the intramolecular Mn−S bond. The ν(CO) frequencies in the IR spectra of solutions and in the solid state are close indicating the monomeric structure in the solid state. The UV−vis spectrum for 12 is presented in Figure 1. Cyclic voltammetry data for radical 12 are in good agreement with those for type 13 radicals.13a Thus, one-electron reduction of 12 in CH3CN is quasi-reversible with ΔEc/a = 106 mV and ia/ ic= 1.02 at −496 mV (Figure 5), while its irreversible one-

Figure 4. Experimental (a, c) and calculated (b, d) EPR spectra at 298 (a) and 77 (c) K of compound 12 dissolved in deuterated toluene in the dark conditions.

organic ligands are paramagnetic existing in 3d5 electron configuration with the electron spin S in a low-spin state equal to 1/2 and the nuclear spin I equal to 5/2, which gives six-line spectrum in solutions. One can see that a spectrum at room temperature can be easily calculated (open circles) with a perfect agreement with the experimental line (Figure 4, spectra a and b). Parameters of the best coincidence are listed in Table 2. Note Figure 5. Cyclic voltammogram in 0.1 M solution of tetraethylammonium tetrafluoroborate in acetonitrile in the presence of 7.8 × 10−3 M of 12. Scan rate 100 mV/s.

Table 2. Spin-Hamiltonian Parameters of Compound 12a parameter

experimental

calculated

giso aiso gzz gxx gyy Azz Axx Ayy

2.034 0.005 14 2.062

2.041 0.005 19 2.064 2.064 1.996 0.010 84 0.001 78 0.002 95

0.011 17

electron oxidation is observed at +812 mV (Figure S33, Supporting Information). One-electron transfer for both reduction and oxidation was calculated by the Randles−Sevcik equation for reversible and irreversible processes in organometallic compounds with a diffusion coefficient of 4.7 × 10−6 cm2/s.15 The formation of 12 according to Scheme 3 suggests the hydrogen loss from the intermediate dicarbonyl complex 9. The structure of the radical chelate 12 was also confirmed by the mass spectra of complexes 6 and 12. In the mass spectra, the intense peaks were observed corresponding to the ions formed after full CO loss. [M-3CO]+ for 6 and [M-2CO]+ for 12 (Figures S29 and S30, Supporting Information). However, in the case of 6, the mass of this ion is equal to 338 D; for 12 it is equal to 337 D. Besides, the fragment ions in the mass spectra of 6 and 12 with masses less than 300 D differ substantially indicating different structures of ions 338 and 337 D. In the IR spectrum of 6 in the solid state, the ν(NH) band16 at 3246 cm−1 is observed, while it is absent in the spectrum of 12, which is also in accord with the suggested structure of compound 12. Unfortunately, we failed to obtain a crystal sample of 12 for Xray analysis. Crystallization under various conditions gave either powders or transparent films on a glass surface. For this reason, we performed DFT B3LYP/6-31G* calculation11 of geometric and energetic parameters for complexes 10 and 12 (Table 1 and Figures S34 and S36). The results show that the radicals 10 and 12 with the Mn−S bond have the deepest local minima. The DFT calculations of the spin density (σ(Mn)) for 12 (Table S4) gave the value 0.683 (79%) for gas phase, indicating that this compound is mainly a Mn-based radical. Complexes 10−12 are stable for several months in the solid state, in benzene, THF, and acetonitrile solutions in the darkness and in the presence of ascorbic acid or hydroquinone.

a and ⟨A⟩ values are given in inverse centimeters.

a

that positions of all hyperfine splitting (hfs) lines are equidistant with high precision at both temperatures. Different amplitudes as well as line widths with alternative broadening indicate that rather bulky complex 12 is rotating in the toluene solution at 298 K anisotropically and not very fast. The EPR spectrum of 12 at 77 K (Figure 4c) demonstrates a three-axes anisotropy of tensors ⟨g⟩ and ⟨A⟩, which was confirmed by theoretical spectra simulation (Figure 4d) reflecting their reasonably good agreement. EPR parameters are given in Table 2. Several complexes of Mn(II) with cyclopentadienyl ring and CO molecules but of simpler structure were investigated by EPR.13 Experimentally measured g|| and A||, analogues of gzz and Azz, were estimated in the ranges of 2.057−2.080 and 0.0091−0.0102 cm−1, correspondingly, which are similar to ours from Table 2. Estimations of g2,3 made as g⊥ in ref 13a are not correct, and A2,3 values were not evaluated. In the IR spectrum of 12, the MCO frequencies (2005 and 1936 cm−1, Table 1) are much higher than those for the corresponding dicarbonyl chelates, which can be associated with an electron-withdrawing effect from the Mn(CO)2 fragment.14 Thus, the similarity of the preparation procedure and the parameters of the IR and EPR spectra of 12 and stable D

DOI: 10.1021/acs.organomet.9b00165 Organometallics XXXX, XXX, XXX−XXX

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Organometallics The photolysis of 12 in benzene and THF solutions under inert atmosphere results in a color change from dark violet to orange. The IR spectra in the ν(MCO) region show the formation of 9 (Table 1). In the UV−vis spectra, new bands at 400 and 500 nm appear instead of the bands at 520 and 650 nm for complex 12 (Table 1 and see Supporting Information). Repeated oxidation of 9 gives again dicarbonyl complex 12. Thus, the low-spin compound 12 and the corresponding chelate 9 form in solution an intermolecular photochromic system. Dicarbonyl chelates 7 and 8 in the presence of oxygen behave similarly (Scheme 3). Unfortunately, under these conditions, the olefin chelate was not formed. We managed to prepare dicarbonyl chelates 16 and 17 by the reaction of isolated chelates 14 and 15 with phenyl isocyanate. The coordination type is established from the X-ray structure of 17 (Figure S32, Supporting Information) and DFT calculations. Bond distances and angles between the manganese and carbon atoms and the geometry of the molecule coincide with those for olefin chelates described earlier.3b,12 It also follows from the 1H and 13C NMR and IR spectra of the olefin chelate 17. While the 1H NMR spectrum of tricarbonyl complex 5 contains four two-proton signals from the protons in the αand β-positions of the Cp-ring and the methylene groups of CpCH2 and NCH2 fragments, in the spectra of 16, there are four one-proton signals from the protons of the Cp-ring and two doublets (AB-system) from the prochiral protons of the CH2 groups. On going from tricarbonyl complexes to dicarbonyl chelates, the following changes were observed in the 13C NMR spectra: the number of signals from the carbon nuclei of the Cpring is increased, and besides, two signals from the CO ligands are observed for chelates 16 and 17, whereas the spectra of complexes 5 and 6 have one signal. In the IR spectra in the ν(CO) region two stretches are observed at 1971 and 1910 cm−1 (Table 1), which coincide with those observed for this type of olefin chelates.12 Photolysis of the olefin-coordinated dicarbonyl chelates 16 and 17 in benzene and THF results in a color change from light yellow to red-orange (λmax 400 and 500 nm) (Table 1). The 1H NMR and IR spectra fully coincide with those of the Scoordinated chelates 8 and 9. The reverse thermal reaction in the absence of CO was monitored by IR spectroscopy (Figure 6). It is seen from Figure 6 and Supporting Information (S7, S8) that S-coordinated chelates 8 and 9 give again olefin chelates 16 and 17 due to the linkage isomerization with τ1/2 248 and 533 min, respectively (Table 1).

Thus, the isomeric chelates 16 and 17 (λmax 340 nm) and 8 and 9 (λmax 400 and 500 nm) are the components of the reversible intramolecular photochromic pairs (Scheme 3). The estimation of the quantum yield for the photoisomerization of 17 to 9 relative to φ 0.8 obtained for the photolysis of S12 gives a value of ∼0.74. It is known that the introduction of organic and organometallic fragments into dendrite molecules is a method for obtaining materials with new properties.3b To perform photoinduced ligand exchange solvent-free, we prepared compound 19 according to Scheme 4. Photolysis of compound 19 containing in a substituent dendrite groups of the zeroth generation in benzene, THF, and cyclohexane leads to a color change from light yellow to redorange (λmax400 and 500 nm, Table 1). The 1H NMR and IR spectra (Table 1, Supporting Information) of the photolysis product are similar to those of 7−9 confirming the formation of the S-coordinated chelate 20. The similarity of spectral properties of the dendrite chelate 20 to those of 7−9 means that the presence of a bulky fragment at the N atom of the thiourea fragment does practically not influence the ability of compound 19 to give upon photolysis dicarbonyl six-membered chelate 20 in accordance with the general Scheme 4. In the absence of carbon monoxide, chelate 20 is stable in solution under argon at room temperature for no less than 12 h. However, as in the case of 7−9, the attempts to isolate the photolysis products failed. In the presence of carbon monoxide, chelate 20 enters the reverse thermal reaction to give the tricarbonyl complex 19. The presence of the isosbestic point in the IR spectra indicates the lack of side products. The irradiation-reverse thermal reaction cycle can be repeated no less than five times without decomposition. Thus, as in the case of 4−6, the dendrite derivative 19 and the corresponding chelate 20 form in solution a reversible intermolecular photochromic system (kinetics data are in Table 1). In the air this photochromic system is also unstable: dicarbonyl chelate is oxidized to the radical 21; its spectral characteristics (Supporting Information) fully coincide with those of the above-described radical complexes 10−12. Compound 19 is oily and can therefore give a transparent layer between KBr windows. This fact allowed us to perform the photolysis solvent-free. The IR spectra in the ν(CO) region before and after the photolysis of 19 in a thin layer are presented in Figure 7. As is seen from Figure 7, after irradiation a band at 1856 cm−1, corresponding to the S-coordinated chelate 20, appears; that is, photochromic pairs can be obtained in solution and solvent-free.

Figure 6. IR monitoring in the ν(CO) region of the thermal linkage isomerization of 9 to 17 in THF for 240 min.

CONCLUSION It was found that photolysis of tricarbonyl cymantrene derivatives containing a thiourea fragment in a substituent 4− 6 and 19 afford dicarbonyl chelates 7−9 and 20 stabilized by the coordination of the CS group to the manganese atom. The process is accompanied by color change and the appearance of new bands at 400 and 500 nm in the UV−vis spectra. In the presence of carbon monoxide, these chelates enter the thermal dark reaction to give the parent tricarbonyl complexes, thus forming photochromic systems. Thermal transformations of chelates 7−9 and 20 to the corresponding tricarbonyl complexes are described by the first-order kinetics with the quality of fit no less than 0.998, which is in accord with the dissociative mechanism of the reverse thermal transformation. The formation of stable Mn-based radicals 10−12 and 21 due to

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DOI: 10.1021/acs.organomet.9b00165 Organometallics XXXX, XXX, XXX−XXX

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Organometallics Scheme 4. Synthesis of Compound 19 and Its Transformations

added phenylisothiocyanate (1.8 mL, 14.6 mmol). The reaction mixture was brought to room temperature and stirred for 3 h, and then solvent was removed under vacuum. The residue was crystallized from hexane−EtOAc (1:1). The yield of 4 was 3.1 g (67%); mp 133−134 °C. 1 H NMR (acetone-d6, 400 MHz): δ 1.53 (d, J = 6.9 Hz, 3H, CH3), 4.87 (m, 1H, H-Cp), 4.98 (m, 1H, H-Cp), 5.19 (m, 1H, H-Cp), 5.30 (m, 1H, H-Cp), 5.35 (m, 1H, CH), 7.19 (s, 1H, NHCH), 7.23 (t, J = 7.4 Hz, 1H, H−C6H5), 7.41 (t, J = 7.5 Hz, 2H, H−C6H5), 7.48 (d, J = 8.6 Hz, 2H, H−C6H5), 8.98 (s, 1H, NHC6H5). 1H NMR (benzene-d6, 400 MHz): δ 0.94 (d, J = 6.4 Hz, 3H, CH3), 3.71 (m, 1H, H-Cp), 3.78 (m, 1H, HCp), 3.95 (m, 1H, H-Cp), 4.28 (m, 1H, H-Cp), 5.71 (m, 1H, NHCH), 5.74 (m, 1H, CH), 6.83 (d, J = 7.4 Hz, 2H, H−C6H5), 6.86 (t, J = 7.5 Hz, 1H, H−C6H5), 7.01 (t, J = 7.7 Hz, 2H, H−C6H5), 7.82 (s, 1H, NHC6H5). 1H NMR (acetonitrile-d3, 400 MHz): δ 1.41 (d, J = 6.9 Hz, 3H, CH3), 4.74 (m, 1H, H-Cp), 4.83 (m, 1H, H-Cp), 5.02 (m, 1H, HCp), 5.07 (m, 1H, H-Cp), 5.55 (m, 1H, CH), 6.48 (d, J = 8.0 Hz, 1H, NHCH), 7.28 (t, J = 7.4 Hz, 1H, H−C6H5), 7.33 (d, J = 7.4 Hz, 2H, H− C6H5), 7.42 (t, J = 7.4 Hz, 2H, H−C6H5), 8.22 (s, 1H, NHC6H5). 13C NMR (acetone-d6, 100 MHz): δ 19.48 (1C, CH3), 47.23 (1C, CH), 80.45 (2C, Cp), 82.65 (1C, Cp), 83.65 (2C, Cp), 124.14 (1C, C6H5), 124.17 (2C, C6H5), 125.26 (1C, C6H5), 129.02 (2C, C6H5), 181.23 (1C, CS), 223.19 (3C, CO). IR (KBr, cm−1): 3388 (νNH), 3280 (νNH), 2020 (νCO), 1931 (νCO). IR (benzene, cm−1): 2019 (νCO), 1938 (νCO). IR (THF, cm−1): 2020 (νCO), 1936 (νCO). IR (acetonitrile, cm−1): 2020 (νCO), 1933 (νCO). UV−Vis (benzene) λ, nm (ε, cm−1 M−1) = 323 (1766). UV−Vis (THF) λ, nm (ε, cm−1 M−1) = 324(1654). Anal. Calcd for C17H15MnN2O3S: C, 53.41; H, 3.95; N, 7.33; Mn, 14.37; S, 8.39. Found: C, 53.24; H, 3.94; N, 7.20; Mn, 14.30; S, 8.55%. N-(Cymantrenylmethyl)-N′-phenyl-N-(2-propen-1-yl)-thiourea 5. To a solution of allylcymantrenylmethylamine 23b (0.5 g, 1.8 mmol) in CH2Cl2 (10 mL) was added phenylisothiocyanate (0.25 mL, 2.1 mmol). The reaction mixture was brought to room temperature and stirred for 5 h, and then solvent was removed under vacuum. The residue was crystallized from hexane−EtOAc (2:1). The yield of 5 was 0.5 g (71%); mp 85−86 °C. 1H NMR (acetone-d6, 400 MHz): δ 4.53 (m, 2H, CH2), 4.84 (s, 2H, CH2), 4.91 (m, 2H, H-Cp), 5.26−5.32 (m, 2H, CH2), 5.35 (m, 2H, H-Cp), 5.94 (m, 1H, CH), 7.14 (t, J = 7.3 Hz, 1H, H−C6H5), 7.29 (t, J = 8.3 Hz, 2H, H−C6H5), 7.35 (d, J = 7.6 Hz, 2H, H−C6H5), 8.41 (s, 1H, NHC6H5). 1H NMR (benzene-d6, 400 MHz): δ 3.50 (m, 2H, CH2), 3.84 (m, 2H, H-Cp), 4.43 (s, 2H, CH2), 4.53 (m, 2H, H-Cp), 4.76−4.81 (m, 2H, CH2), 5.17 (m, 1H, CH), 6.83 (br.s, 1H, NHC6H5), 7.14 (t, J = 7.4 Hz, 1H, H−C6H5), 7.13 (t, J = 8.1 Hz, 2H, H−C6H5), 7.37 (d, J = 7.6 Hz, 2H, H−C6H5). IR (benzene, cm−1): 2022 (νCO), 1937 (νCO). IR (THF, cm−1): 2021 (νCO), 1936 (νCO). UV−Vis (benzene) λ, nm (ε, cm−1 M−1) = 334 (1177). Anal. Calcd for C19H17MnN2O3S: C, 55.88; H, 4.20; N, 6.86; Mn, 13.4. Found: C, 56.13; H, 4.44; N, 6.78; Mn, 13.3%. N-(1-Cymantrenylethyl)-N′-phenyl-N-(2-propen-1-yl)-thiourea 6. To a solution of allylcymantrenylethylamine 33b (0.6 g, 2.1 mmol) in CH2Cl2 (50 mL) was added phenyl isothiocyanate (0.3 mL,

Figure 7. IR monitoring in the ν(CO) region of photolysis of 19 as a capillary layer. (A) 19 and (B) 4 min after the irradiation of 19 (50% conversion); (C) after interaction with air.

oxidation of chelates 7−9 and 20 was for the first time proved. Complexes 10−12 and 21 and chelates 7−9 and 20 form in solution stable photochromic systems. Dicarbonyl olefin chelates 16 and 17 were isolated; the photolysis of these complexes results in the formation of stable photochromic pairs due to linkage isomerization via the dissociative mechanism. Photolysis of compound 19 containing dendrite fragments in the substituent results in intermolecular photochromic systems both in solution and solvent-free. The introduction of bulky fragments in the substituent does not affect chelate formation and the properties of photochromic systems.

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EXPERIMENTAL SECTION

1

H and 13C NMR spectra were measured on a Bruker Avance 400 (400.13 and 100.61 MHz, respectively) spectrometer. Chemical shifts δ were referenced to tetramethylsilane (TMS) in parts per million using residual solvent protons as an internal standard. If necessary, the signals in 1H NMR spectra were assigned using two-dimensional (2D) COSY, NOESY, and JMODCHO experiments. IR spectra were recorded on a Tensor 37 (Bruker) IR Fourier spectrometer and Nicolet Magna 750IR with a resolution of 2 cm−1 in CaF2 cells. UV−Vis spectra were recorded on a Specord M-40 spectrophotometer. Electron impact (EI) mass spectra were recorded on Kratos MS 890 and Finnigan POLARIS Q spectrometers at 70 eV, with the temperature of the ionization chamber being 250 °C. Silica gel 60 (Merck) was used for column chromatography. THF, hexane, and benzene were purified by conventional methods and distilled from sodium benzophenone ketyl under an argon atmosphere. The photochemical reactions were performed using a Hereaus TQ 150 Hg immersion lamp. N-(1-Cymantrenylethyl)-N′-phenylthiourea 4. To a solution of 1-cymantrenylethylamine 117 (3 g, 12.2 mmol) in CH2Cl2 (50 mL) was F

DOI: 10.1021/acs.organomet.9b00165 Organometallics XXXX, XXX, XXX−XXX

Article

Organometallics

26.05 (2C, C10H21), 29.18 (2C, C10H21), 29.34 (2C, C10H21), 29.36 (4C, C10H21), 29.59 (4C, C10H21), 31.91 (2C, C10H21), 48.57 (1C, CH), 52.72 (1C, NCH2), 68.26 (2C, OCH2), 79.03 (1C, Cp), 83.14 (1C, Cp), 83.90 (1C, Cp), 84.48 (1C, Cp), 100.80 (1C, C6H3), 104.11 (1C, Cp), 104.43 (2C, C6H3), 125.84 (2C, C6H3), 126.11 (1C, C6H3), 128.60 (2C, C6H5), 137.45 (1C, C6H5), 139.45 (1C, C6H5), 161.25 (2C, C6H5), 183.09 (1C, CS), 224.42 (3C, CO). IR (benzene, cm−1): 3370 (νNH), 2023 (νCO), 1938 (νCO). IR (cyclohexane, cm−1): 3371 (νNH), 2027 (νCO), 1944 (νCO). IR (capillary layer, cm−1): 3365 (νNH), 2021 (νCO), 1933 (νCO). UV−Vis (benzene) λ, nm (ε, cm−1 M−1) = 332 (1263). UV−Vis (cyclohexane) λ, nm (ε, cm−1 M−1) = 329 (1487). Anal. Calcd for C44H61MnN2O5S: C, 67.32; H, 7.83; N, 3.57; S, 4.09;Mn, 7.0. Found: C, 67.35; H, 7.52; N, 3.53; S, 3.96; Mn, 6.9%. The General Procedure for Spectral Studies of Photochemical Reactions of Tricarbonyl Complexes 4−6 and 19, Dicarbonyl Chelates, and Their Izomerization. Solutions of tricarbonyl compounds in a required solvent (benzene, THF, acetonitrile, or cyclohexane) (C = 2−4 mM) were placed in an argon atmosphere into an IR or UV cell, and the samples were irradiated with Hg lamp (steady radiation of the lamp was achieved 2 min before irradiation), and the spectra were registered every 1−2 min. Then irradiation of the sample was repeated up to full conversion of tricarbonyl complexes or 50% izomerisation of dicarbonyl chelates. To prepare samples for NMR monitoring, solutions of compounds (c = 10−15 mM) were filtered into an NMR ampule, bubbled with argon, and irradiated with the Hg lamp at 8−10 °C during 4 min up to 30− 50% conversion. The distance between the lamp and the sample was 5 cm in all cases. The width of irradiation window was 2 cm in the case of IR cell, 1 cm in the case of UV cell, and 5 mm in the case of NMR ampule. Monitoring of all thermal reactions of irradiated samples was performed by similar manner for 72 h at least. [N-(1-η5-Cyclopentadyenylethyl)-N′-phenyl-κS-thiourea](dicarbonyl)manganese 7. 1H NMR (benzene-d6, 400 MHz): δ 0.89 (d, J = 6.4 Hz, 3H, CH3), 3.17 (m, 1H, H-Cp), 3.89 (m, 1H, H-Cp), 3.89 (m, 1H, CH), 4.32 (m, 1H, H-Cp), 4.49 (m, 1H, H-Cp), 5.54 (m, 1H, NHCH), 6.43 (d, J = 7.2 Hz, 2H, H−C6H5), 6.77 (m, 1H, H− C6H5), 6.88 (t, J = 7.6 Hz, 2H, H−C6H5), 7.67 (s, 1H, NHC6H5). 1H NMR (acetonitrile-d3, 400 MHz): δ 1.40 (d, J = 6.5 Hz, 3H, CH3), 4.36 (m, 1H, H-Cp), 4.43 (m, 1H, H-Cp), 4.59 (m, 1H, CH), 4.66 (m, 1H, H-Cp), 4.83 (m, 1H, H-Cp), 5.43 (d, J = 8.0 Hz, 1H, NHCH), 7.28 (m, 1H, H−C6H5), 7.33 (m, 2H, H−C6H5), 7.42 (m, 2H, H−C6H5), 8.16 (s, 1H, NHC6H5). IR (benzene, cm−1): 1927 (νCO), 1863 (νCO). IR (THF, cm−1): 1920 (νCO), 1853 (νCO). IR (acetonitrile, cm−1): 1917 (νCO), 1846 (νCO). UV−Vis (benzene) λ, nm (ε, cm−1 M−1) = 403 (958); 508 (877). UV−Vis (THF) λ, nm (ε, cm−1 M−1) = 394 (642); 494 (584). [N-(η5-Cyclopentadyenylmethyl)-N′-phenyl-N-(2-propen-1yl)-κS-thiourea](dicarbonyl)manganese 8. 1H NMR (benzene-d6, 400 MHz): δ 3.06 (m, J = 5.7 Hz, 2H, CH2), 3.12 (s, 2H, CH2), 3.94 (m, 2H, H-Cp), 4.31 (m, 2H, H-Cp), 4.48−4.71 (m, 2H, J = 17.0, 10.3 Hz, CH2=), 4.98 (m, 1H, CH = ), 6.60 (br.s, 1H, NHC6H5), 6.76 (d, J = 8.3 Hz, 2H, H−C6H5), 6.82 (t, J = 7.9 Hz, 1H, H−C6H5), 6.99 (t, J = 7.6 Hz, 2H, H−C6H5). IR (benzene, cm−1): 3368 (νNH), 1927 (νCO), 1862 (νCO). IR (THF, cm−1): 1921 (νCO), 1855 (νCO). UV−Vis (benzene) λ, nm (ε, cm−1 M−1) = 390 (1082); 495 (479). UV−Vis (THF) λ, nm (ε, cm−1 M−1) = 418 (1242); 502 (994). [N-(1-η5-Cyclopentadyenylethyl)-N′-phenyl-N-(2-propen-1yl)-κS-thiourea](dicarbonyl)manganese 9. 1H NMR (benzene-d6, 400 MHz): δ 1.03 (d, J = 6.7 Hz, 3H, CH3), 3.03 (m, 1H, CH2), 3.28 (m, 1H, CH2), 3.73 (m, 1H, CH), 4.22 (m, 1H, H-Cp), 4.25 (m, 1H, HCp), 4.46 (m, 1H, H-Cp), 4.53−4.80 (m, 2H, CH2), 4.73 (m, 1H, HCp), 5.01 (m, 1H, CH), 6.54 (br.s, 1H, NHC6H5), 6.65 (d, J = 7.7 Hz, 2H, H−C6H5), 6.80 (t, J = 7.7 Hz, 1H, H−C6H5), 6.94 (t, J = 7.8 Hz, 2H, H−C6H5). IR (benzene, cm−1): 1938 (νCO), 1856 (νCO). IR (THF, cm−1): 3223 (νNH), 1923 (νCO), 1857 (νCO). IR (acetonitrile, cm−1): 1916 (νCO), 1846 (νCO). UV−Vis (benzene) λ, nm (ε, cm−1 M−1) = 432 (1002); 504 (839). UV−Vis (THF) λ, nm (ε, cm−1 M−1) = 435 (1114); 503 (1142). [N-(3,5-Bis(decyloxyl)benzyl)-N-(1-η5-cyclopentadyenylethyl)-N′-phenyl-κS-thiourea](dicarbonyl)manganese 20. 1H

2.5 mmol). The reaction mixture was brought to room temperature and stirred for 5 h, and then the solvent was removed under vacuum. The residue was crystallized from hexane−CH2Cl2 (2:1). The yield of 6 was 3.1 g (67%); mp 115−116 °C. 1H NMR (acetone-d6, 400 MHz): δ 1.53 (d, J = 7.1 Hz, 3H, CH3), 4.30 (m, 2H, CH2), 4.86 (m, 1H, H-Cp), 5.04 (m, 1H, H-Cp), 5.25−5.37 (m, 2H, CH2), 5.28 (m, 1H, H-Cp), 5.37 (m, 1H, H-Cp), 5.85 (m, 1H, CH), 6.92 (m, 1H, CH), 7.16 (t, J = 7.3 Hz, 1H, H−C6H5), 7.31 (t, J = 7.4 Hz, 2H, H−C6H5), 7.35 (d, J = 7.6 Hz, 2H, H−C6H5), 8.20 (s, 1H, NHC6H5). 1H NMR (benzene-d6, 400 MHz): δ 0.98 (d, J = 7.1 Hz, 3H, CH3), 3.24 (m, 2H, CH2), 3.75 (m, 1H, H-Cp), 3.94 (m, 1H, H-Cp), 4.09 (m, 1H, H-Cp), 4.71−4.82 (m, 2H, CH2), 4.83 (m, 1H, H-Cp), 5.12 (m, 1H, CH), 6.96(m, 1H, CH),6.99 (t, J = 7.3 Hz, 1H, H−C6H5), 7.10 (t, J = 7.6 Hz, 2H, H− C6H5), 7.12 (s, 1H, NHC6H5), 7.50 (d, J = 7.6 Hz, 2H, H−C6H5). 13C NMR (acetone-d6, 100 MHz): δ 15.66 (1C, CH3), 46.08 (1C, CH), 52.16 (1C, CH2), 79.53 (1C, Cp), 84.19 (1C, Cp), 84.44 (1C, Cp), 84.82 (1C, Cp), 105.03 (1C, Cp), 116.66 (1C, CH2), 125.03 (1C, C6H5), 125.87 (2C, C6H5), 127.97 (2C, C6H5), 133.90 (1C, CH), 140.72 (1C, C6H5), 182.06 (1C, CS), 225.22 (3C, CO). IR (KBr, cm−1): 3246 (νNH), 2020 (νCO), 1931 (νCO). IR (benzene, cm−1): 2020 (νCO), 1935 (νCO). IR (THF, cm−1): 2019 (νCO), 1934 (νCO). IR (acetonitrile, cm−1): 2020 (νCO), 1932 (νCO). UV−Vis (benzene) λ, nm (ε, cm−1 M−1) = 332 (1594). UV−Vis (THF) λ, nm (ε, cm−1 M−1) = 332 (2082). Mass spectrometry (MS) (EI): m/z (related intensity, %): 338 (80) [M − 3CO]+. Anal. Calcd for C20H19MnN2O3S: C, 56.87; H, 4.53; N, 6.63; Mn, 13.01; S, 7.59. Found: C, 56.74; H, 4.56; N, 6.73; Mn, 13.20; S, 7.66%. 3,5-Bis(decyloxyl)benzyl-(1-cymantrenylethyl)amine 18. 3,5Decyloxybenzyl bromide (1.9 g, 3.8 mmol) was added to amine 1 (0.9 g, 3.8 mmol), and the mixture was grated thoroughly. After the reaction mixture had solidified, it was rubbed thoroughly with a glass rod and kept at room temperature for 12 h. Then, 1 N NaOH was added, and the product was extracted with AcOEt. The organic layer was separated, washed with 1 N NaOH and brine, and dried with MgSO4. The solvent was removed under vacuum, and 18 (yellow oil) was isolated by column chromatography (hexane/AcOEt, 10:1). The yield of 18 was 1.2 g (48%). 1H NMR (CDCl3, 400 MHz): δ 0.96 (t, J = 6.9 Hz, 6H, CH3), 1.35 (m, 24H, CH2), 1.42 (d, J = 6.6 Hz, 3H, CH3), 1.51 (m, 4H, CH2), 1.82 (m, 4H, CH2), 3.57 (m, 1H, CH), 3.82 (m, 2H, NCH2), 3.99 (t, J = 6.4 Hz, 4H, OCH2), 4.70 (m, 2H, H-Cp), 4.88 (m, 1H, H-Cp), 4.93 (m, 1H, H-Cp), 6.42 (m, 1H, H−C6H3), 6.54 (m, 2H, H−C6H3). 13C NMR (CDCl3): δ 14.15 (2C, C10H21), 22.71 (1C, CH3), 26.08 (2C, C10H21), 29.31 (2C, C10H21), 29.36 (2C, C10H21), 29.43 (4C, C10H21), 29.61 (4C, C10H21), 31.93 (2C, C10H21), 49.88 (1C, CH), 51.45 (1C, NCH2), 68.00 (2C, OCH2), 80.92 (1C, Cp), 80.99 (1C, Cp), 82.34 (1C, Cp), 83.20 (1C, Cp),99.96 (1C, Cp), 102.83 (1C, C6H3), 106.32 (2C, C6H3), 142.15 (1C, C6H3), 160.45 (2C, C6H3), 225.06 (3C, CO). Anal. Calcd for C37H54MnNO5: C, 68.59; H, 8.40; N, 2.16; Mn, 8.5. Found: C, 68.49; H, 8.49; N, 2.02; Mn, 8.5%. N-(3,5-Bis(decyloxyl)benzyl)-N-(1-cymantrenylethyl)-N′phenylthiourea 19. To a solution of 18 (0.6 g, 0.9 mmol) in CH2Cl2 (10 mL) was added phenylisothiocyanate (0.16 mL, 1.2 mmol). The reaction mixture was brought to room temperature and stirred for 5 h. The solvent was removed under vacuum, and 19 (yellow oil) was isolated by column chromatography (hexane/AcOEt, 4:1). The yield of 19 was 0.5 g (71%). 1H NMR (CDCl3, 400 MHz): δ 0.96 (t, J = 6.8 Hz, 6H, CH3), 1.34 (m, 24H, CH2), 1.49 (m, 4H, CH2), 1.56 (d, J = 7.0 Hz, 3H, CH3), 1.83 (m, 4H, CH2), 3.96 (t, J = 6.4 Hz, 4H, OCH2), 4.62 (s, 2H, NCH2), 4.63 (m, 1H, H-Cp), 4.81 (m, 1H, H-Cp), 4.97 (m, 1H, HCp), 5.35 (m, 1H, H-Cp), 6.39 (m, 2H, H−C6H3) 6.44 (m, 1H, H− C6H3), 6.96 (m, 1H, CH), 7.20 (s, 1H, NHC6H5), 7.23 (m, 3H, H− C6H5), 7.35 (m, 2H, H−C6H5). 1H NMR (benzene-d6, 400 MHz): δ 0.92 (t, J = 6.9 Hz, 6H, CH3), 1.14 (d, J = 7.0 Hz, 3H, CH3), 1.27 (m, 24H, CH2), 1.36 (m, 4H, CH2), 1.66 (m, 4H, CH2), 3.70 (t, J = 6.4 Hz, 4H, OCH2), 3.76 (m, 1H, H-Cp), 4.03 (m, 1H, H-Cp), 4.07 (s, 2H, NCH2), 4.13 (m, 1H, H-Cp), 5.03 (m, 1H, H-Cp), 6.39 (d, J = 1.6 Hz, 2H, H−C6H3), 6.61 (t, J = 1.6 Hz, 1H, H−C6H3), 6.88 (t, J = 7.4 Hz, 1H, H−C6H5), 7.05 (t, J = 7.4 Hz, 2H, H−C6H5), 7.15 (br.s, 1H, NHC6H5), 7.17 (m, 1H, CH), 7.35 (d, J = 7.6 Hz, 2H, H−C6H5). 13C NMR (CDCl3, 100 MHz): δ 14.14 (2C, C10H21), 22.70 (1C, CH3), G

DOI: 10.1021/acs.organomet.9b00165 Organometallics XXXX, XXX, XXX−XXX

Article

Organometallics

1967 (νCO), 1905 (νCO). IR (THF, cm−1): 3298 (νNH), 1965 (νCO), 1902 (νCO). UV−Vis (benzene) λ, nm (ε, cm−1 M−1) = 329 (3586). UV−Vis (THF) λ, nm (ε, cm−1 M−1) = 321 (1661). Anal. Calcd for C18H17MnN2O2S: C, 56.84; H, 4.51; N, 7.37; Mn, 14.4. Found: C, 56.91; H, 4.58; N, 7.27; Mn, 14.3%. [N-(1-η5-Cyclopentadyenylethyl)-N′-phenyl-N-(η2-2-propen1-yl)-thiourea](dicarbonyl)manganese 17. To a solution of chelate 15 (0.26 g, 1.0 mmol) in CH2Cl2 (3 mL) was added phenyl isothiocyanate (0.12 mL, 1.0 mmol). The reaction mixture was brought to room temperature and stirred for 5 h, and then the solvent was removed under vacuum. The residue was crystallized from hexane− CH2Cl2 (2:1). The yield of 17 was 0.3 g (76%); mp 78 °C. 1H NMR (benzene-d6, 400 MHz, 330 K): δ 0.93 (d, J = 6.9 Hz,3H, CH3), 1.51 (dd, J1 = 15.8, J2 = 4.6 Hz, 1H, CH), 1.73 (d, J = 7.9 Hz, 1H, CH2), 2.04 (d, J = 10.7 Hz, 1H, CH2), 2.87 (m, 1H, H-Cp), 3.02 (m, 1H, CH2), 3.71 (m, 1H, H-Cp), 4.28 (m, 1H, CH2), 4.45 (m, 1H, H-Cp), 5.20 (m, 1H, H-Cp), 6.34 (m, 1H, CH), 7.00 (s, 1H, NHC6H5), 7.09 (m, 1H, H−C6H5), 7.30 (m, 2H, H−C6H5), 7.50 (m, 2H, H−C6H5). 13 C NMR (benzene-d6, 100 MHz): δ 16.82 (1C, CH3), 37.38 (1C, CH2), 48.35 (1C, CH), 52.62 (1C, CH2), 70.70 (1C, CH), 84.08 (1C, Cp), 87.47 (1C, Cp), 88.34 (2C, Cp), 105.60 (1C, Cp), 125.56 (1C, C6H5), 126.02 (2C, C6H5), 128.74 (2C, C6H5), 140.76 (1C, C6H5), 182.12 (1C, CS), 232.14 (1C, CO), 234.43 (1C, CO). 13C NMR (acetone-d6, 100 MHz): δ 16.96 (1C, CH3), 37.28 (1C, CH2), 48.21 (1C, CH), 54.09 (1C, CH2), 70.78 (1C, CH), 84.87 (1C, Cp), 88.52 (2C, Cp), 88.67 (1C, Cp), 106.13 (1C, Cp), 124.86 (1C, C6H5), 126.51 (2C, C6H5), 127.90 (2C, C6H5), 141.27 (1C,C6H5), 180.95 (1C, CS), 232.79 (1C, CO), 234.71 (1C, CO). IR (benzene, cm−1): 1971 (νCO), 1910 (νCO). IR (THF, cm−1): 3309 (νNH), 1968 (νCO), 1907 (νCO). UV−Vis (benzene) λ, nm (ε, cm−1 M−1) = 334 (2613). UV−Vis (THF) λ, nm (ε, cm−1 M−1) = 331 (645). Anal. Calcd for C19H19MnN2O2S: C, 57.87; H, 4.84; N, 7.10; Mn, 13.9. Found: C, 58.02; H, 4.99; N, 6.90; Mn, 13.8%. Radical from [N-(1-η5-Cyclopentadyenylethyl)-N′-phenylκS-thiourea](dicarbonyl)manganese 10. After the general irradiation procedure, the reaction mixture was bubbled with air for 1 h. The solvent was removed by rotary evaporation at low temperature; the residue was separated by silica gel column chromatography with benzene as an eluent and crystallized from benzene−EtOAc (2:1). 0.507 g (1.3 mmol) of 4 gave violet residue of 10 of 0.3 g (64%); mp 98 °C. IR (KBr, cm−1): 3390 (νNH), 2000 (νCO), 1928 (νCO). IR (benzene, cm−1): 2005 (νCO), 1936 (νCO). IR (THF, cm−1): 2004 (νCO), 1933 (νCO). IR (acetonitrile, cm−1): 2004 (νCO), 1936 (νCO). UV−Vis (benzene) λ, nm (ε, cm−1 M−1) = 503 (2272); 629 (867). UV−Vis (THF) λ, nm (ε, cm−1 M−1) = 492 (917); 616 (122). Anal. Calcd for C16H14MnN2O2S: C, 54.39; H, 3.99; N, 7.93; S, 9.07; Mn, 15.5. Found: C, 54.42; H, 4.01; N, 7.88; S, 8.99; Mn, 15.3%. Radical from [N-(η5-Cyclopentadyenylmethyl)-N′-phenyl-N(2-propen-1-yl)-κS-thiourea](dicarbonyl)manganese 11. After the general irradiation procedure, 0.51 g (1.2 mmol) of 5 gave violet residue of 11 of 0.36 g (76%); mp 83 °C. IR (benzene, cm−1): 2002 (νCO), 1934 (νCO). IR (THF, cm−1): 2004 (νCO), 1933 (νCO). UV−Vis (benzene) λ, nm (ε, cm−1 M−1) = 502 (607), 605 (107). UV−Vis (THF) λ, nm (ε, cm−1 M−1) = 496 (1078); 590 (509). Anal. Calcd for C18H16MnN2O2S: C, 56.99; H, 4.25; N, 7.38; S, 8.45; Mn, 14.5. Found: C, 56.91; H, 4.11; N, 7.34; S, 8.31; Mn, 14.3%. Radical from [N-(1-η5-Cyclopentadyenylethyl)-N′-phenyl-N(2-propen-1-yl)-κS-thiourea](dicarbonyl)manganese 12. After the general irradiation procedure, 0.33 g (0.8 mmol) of 6 gave violet residue of 12 of 0.13 g (42%); mp 62 °C. IR (KBr, cm−1): 2001 (νCO), 1930 (νCO). IR (benzene, cm−1): 2005 (νCO), 1939 (νCO). IR (THF, cm−1): 2003 (νCO), 1934 (νCO). IR (acetonitrile, cm−1): 2002 (νCO), 1932 (νCO). UV−Vis (benzene) λ, nm (ε, cm−1 M−1) = 503 (1024); 629 (391). UV−Vis (THF) λ, nm (ε, cm−1 M−1) = 502 (1521); 662 (476). MS (EI): m/z (related intensity,%): 337 (80) [M-2CO]+. Anal. Calcd for C19H18MnN2O2S: C, 57.87; H, 4.86; N, 7.10; S, 8.13; Mn, 14.0. Found: C, 58.08; H, 4.72; N, 7.07; S, 8.21; Mn, 13.9%. Radical from [N-(3,5-Bis(decyloxyl)benzyl)-N-(1-η5-cyclopentadyenylethyl)-N′-phenyl)-κS-thiourea](dicarbonyl)manganese 21. IR (benzene, cm−1): 2005 (νCO), 1936 (νCO). IR

NMR (benzene-d6, 400 MHz): δ 0.92 (m, 6H, CH3), 1.08 (d, J = 6.8 Hz, 3H, CH3), 1.27 (m, 24H, CH2), 1.43 (m, 4H, CH2), 1.73 (m, 4H, CH2), 3.31 (d, J = 14.9 Hz, 1H, CH2), 3.73 (m, 1H, H-Cp), 3.83 (t, J = 6.6 Hz, 4H, OCH2), 3.88 (m, 1H, CH), 3.97 (m, 1H, H-Cp), 4.15 (m, 1H, H-Cp), 4.33 (d, J = 14.9 Hz, 1H, CH2), 4.44 (m, 1H, H-Cp), 6.36 (m, 1H, H−C6H3), 6.64 (m, 2H, H−C6H3), 6.66 (br.s, 1H, NHC6H5), 6.82 (t, J = 7.8 Hz, 1H, H−C6H5), 6.96 (t, J = 7.8 Hz, 2H, H−C6H5), 7.18 (d, 2H, H−C6H5). IR (benzene, cm−1): 3368 (νNH), 1927 (νCO), 1862 (νCO). IR (cyclohexane, cm−1): 3220 (νNH), 1938 (νCO), 1877 (νCO). IR (capillary layer, cm−1): 3200 (νNH), 1927 (νCO), 1856 (νCO). UV−Vis (benzene) λ, nm (ε, cm−1 M−1) = 371 (898); 495 (387). UV− Vis (cyclohexane) λ, nm (ε, cm−1 M−1) = 362 (548); 500 (252). General Procedure for Obtaining Dicarbonyl Chelates. A solution of a tricarbonyl compound in THF (250 mL) was irradiated for 30−40 min with a Hg lamp under argon in an immersion-well photochemical reactor at 7−10 °C. The reactions were monitored by IR spectra of probes of the reaction solution. The solvent was removed by rotary evaporation at low temperature; the residue was separated by silica gel column chromatography with benzene as an eluent and crystallized from benzene. [N-(η 2 -2-Propen-1-yl)-N-(η 5 -cyclopentadyenylmethyl)amine](dicarbonyl)manganese 14. After the general irradiation procedure, N-allylcymantrenylmethylamine 2 (0.61 g, 2.2 mmol) gave yellow oil of 14 0.34 g (63%). 1H NMR (CDCl3, 400 MHz): δ 0.84 (br. s, 1H, NH), 1.87 (br.d, 1H, CH2), 2.25 (m, 2H, CH2), 2.52 (m, 1H, CH2), 2.78 (br.d, 1H, CH2), 3.04 (m, 1H, CH), 3.63 (br.d, 1H, CH2), 4.17 (m, 1H, H-Cp), 4.21 (m, 1H, H-Cp), 4.95 (m, 1H, H-Cp), 5.29 (m, 1H, H-Cp). IR (THF, cm−1): 1958 (νCO), 1895 (νCO). Anal. Calcd for C11H12MnNO2: C, 53.90; H, 4.90; N, 5.72; Mn, 22.42. Found: C, 54.07; H, 5.02; N, 5.63; Mn, 22.30%. [N-(2-Propen-1-yl)-N-(1-η5-cyclopentadyenylethyl)amine](dicarbonyl)manganese 15. After the general irradiation procedure, N-allylcymantrenylethylamine 3 (0.4 g, 1.5 mmol) gave yellow oil of 15 0.26 g (67%). 1H NMR (benzene-d6, 400 MHz): δ 0.45 (br. s, 1H, NH), 0.89 (d, J = 6.4 Hz, 3H, CH3), 1.96 (d, J = 8.4 Hz, 1H, CH2), 2.30 (m, 1H, CH), 2.49 (d, J = 12.3 Hz, 1H, CH2), 2.55 (d, J = 12.7 Hz, 1H, CH2), 3.00 (m, 1H, CH), 3.40 (d, J = 15.2 Hz, 1H, CH2), 3.78 (m, 1H, H-Cp), 3.85 (m, 1H, H-Cp), 4.50 (m, 1H, H-Cp), 4.87 (m, 1H, H-Cp). 13C NMR (benzene-d6, 100 MHz): δ 29.93 (1C, CH3), 48.41 (1C, CH2), 51.87 (1C, CH), 60.91 (1C, CH2), 69.40 (1C, CH), 85.31 (1C, Cp), 85.84 (1C, Cp), 86.22 (2C, Cp), 99.08 (1C, Cp), 233.86 (1C, CO), 235.99 (1C, CO). IR (THF, cm−1): 3309 (νNH), 1957 (νCO), 1895 (νCO). Anal. Calcd for C12H14MnNO2: C, 55.61; H, 5.44; N, 5.40; Mn, 21.20. Found: C, 55.72; H, 5.57; N, 5.23; Mn, 21.25%. [N-(η5-Cyclopentadyenylmethyl)-N′-phenyl-N-(η2-2-propen1-yl)-thiourea](dicarbonyl)manganese 16. To a solution of chelate 14 (0.20 g, 0.8 mmol) in CH2Cl2 (3 mL) was added phenyl isothiocyanate (0.11 mL, 0.8 mmol). The reaction mixture was brought to room temperature and stirred for 5 h, and then solvent was removed under vacuum. The residue was crystallized from hexane−CH2Cl2 (2:1). The yieldof 16 was 0.28 g (90%); mp 149−150 °C. 1H NMR (acetone-d6, 400 MHz): δ 1.90 (d, J = 8.5 Hz, 1H, CH2), 2.49 (d, J = 12.1 Hz, 1H, CH2=), 3.01 (m, 1H, CH = ), 3.79 (d, J = 14.2 Hz, 1H, CH2), 4.03 (dd, J1 = 17.1, J2 = 2.5 Hz, 1H, CH2), 4.35 (m, 1H, H-Cp), 4.53 (m, 1H, H-Cp), 4.68 (dd, J1 = 17.2 Hz, J2 = 3.8 Hz, 1H, CH2), 5.42 (m, 2H, H-Cp), 5.59 (d, J = 14.2 Hz, 1H, CH2), 7.15 (m, 1H, H− C6H5), 7.30 (m, 2H, H−C6H5), 7.38 (m, 2H, H−C6H5), 8.68 (br.s, 1H, NHC6H5). 1H NMR (benzene-d6, 400 MHz): δ 1.59 (d, J = 8.6 Hz, 1H, CH2=), 2.03 (d, J = 12.4 Hz, 1H, CH2=), 2.32 (m, 1H, CH), 2.56 (d, J = 14.3 Hz, 1H, CH2), 2.80 (dd, J1 = 17.3 Hz, J2 = 2.0 Hz, 1H, CH2), 3.51 (dd, J1 = 17.2 Hz, J2 = 3.2 Hz, 1H, CH2), 3.55 (m, 1H, H-Cp), 3.99 (m, 1H, H-Cp), 4.35 (m, 1H, H-Cp), 4.62 (m, 1H, H-Cp), 5.78 (d, J = 14.3 Hz, 1H, CH2), 6.99 (m, 1H, H−C6H5), 7.30 (m, 2H, H−C6H5), 7.38 (m, 2H, H−C6H5), 8.68 (br.s, 1H, NHC6H5). 13C NMR (benzene-d6, 100 MHz): δ 30.46 (1C, CH2), 47.76 (1C, CH2), 48.57 (1C, CH2), 69.95 (1C, CH), 86.99 (2C, Cp), 87.24 (1C, Cp), 87.97 (1C, Cp), 94.92 (1C, Cp), 125.57 (1C, C6H5), 125.69 (2C, C6H5), 128.55 (2C, C6H5), 140.14 (1C, C6H5), 181.71 (1C, CS), 229.55 (1C, CO), 229.85 (1C, CO). IR (benzene, cm−1): 3396 (νNH), H

DOI: 10.1021/acs.organomet.9b00165 Organometallics XXXX, XXX, XXX−XXX

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Organometallics (cyclohexane, cm−1): 2002 (νCO), 1938 (νCO). IR (capillary layer, cm−1): 2006 (νCO), 1934 (νCO). UV−Vis (benzene) λ, nm (ε, cm−1 M−1) = 509 (946); 639 (251). UV−Vis (cyclohexane) λ, nm (ε, cm−1 M−1) = 507 (1026); 651 (383). Estimation of Quantum Yield for Obtaining 9 from 6. A 2.0 mL portion of a 1.60 × 10−3 M solution of 6 in benzene (ε370 376) was added to 1.75 mL of a 1.63 × 10−3 M solution of [(1-η2-allyloxy-2pyrid-2-ylethyl)-η5-cyclopentadienyl](dicarbonyl)manganese S in benzene (ε370 421), and the mixture was saturated with argon. Aliquots of the solution prepared with the total absorption 0.70 at 370 nm with that of 0.35 for each component were transferred into an IR cell (KBr, 0.21 mm, 3 × 1.5 cm2) and irradiated with the 365 nm band of a Hg lamp by application of UVS-6 + BS-7 filters (made in Russia) from a distance of 5 cm. The concentration decrease for both complexes was determined from the absorbance of the IR band 2020 cm−1 for thiourea 6 and 1901 cm−1 for S, which do not overlap with ν(CO) bands of the products. At 12−13% conversion of 6 to the corresponding chelate 9 (ε370 436), 8− 9% isomerization of S to the pyridine chelate (ε370 1068) occurred. These data together with φ 0.8 for photoisomerization of S allowed us to obtain a quantum yield of 0.96 for photolysis of 6. Estimation of Quantum Yield for Obtaining 9 from 17. A 1.33 mL portion of a 1.36 × 10−3 M solution of 17 in benzene (ε370 527) was added to 1.0 mL of a 1.63 × 10−3 M solution of S in benzene (ε370 337), and the mixture was saturated with argon. Aliquots of the solution prepared with the total absorption 0.76 at 370 nm with that of 0.38 for each component were transferred into an IR cell (KBr, 0.21 mm, 3 × 1.5 cm2) and irradiated with the 365 nm band of a Hg lamp by application of UVS-6 + BS-7 filters (made in Russia) from a distance of 5 cm. The concentration decrease for both complexes was determined from the absorbance of the IR band 1912 cm−1 for 17 and 1901 cm−1 for S, which do not overlap with ν(CO) bands of the products. At 7−8% conversion of 17 to the corresponding chelate 9, 10−11% isomerization of S to the pyridine chelate occurred. These data together with φ 0.8 for photoisomerization of S allowed us to obtain a quantum yield of 0.74 for photolysis of 17. EPR Measurements. The EPR spectra were recorded with a Bruker ELEXSYS-E500 EPR spectrometer (frequency of 9.5 GHz, X-band) at 298 and 77 K. Deuterated toluene C7D8 was used as a solvent glassing in a frozen state for narrowing the EPR lines. Concentration of 12 in solutions was constant and equal to 5.0 mmol/dm3 to avoid line broadening due to electron spin exchange and magnetic dipole−dipole coupling.18 A modulation frequency of 100 kHz and a microwave power of 0.2 mW were used. EPR spectra at 77 K were recorded in a finger Dewar, and the sample was centered directly in the spectrometer cavity for measurements and illumination. As the light source, a tungsten halogen lamp (50 W, Δλ = 350−900 nm) was used with illumination intensity of ca. 20 mW·cm−2. Determining the g-factor values, gzz, giso, and hfs constants Azz and aiso of compound 12 from experimental EPR spectra was performed by a standard procedure.19 Simulation of the EPR spectra was performed by the iterativegradient method with varying spin-Hamiltonian parameters characterizing a line width of the individual resonance line using a program package “ESRcom4”.20 Main axes of the Zeeman, g-, and hfs A-tensors were assumed as coincide, and the line width B-tensor was chosen as isotropic. Electrochemistry. Electrochemical measurements were performed in a standard glass three-electrode unit using a IPC-PRO potentiostat (Russia) linked to personal computer (PC). Working electrode is a 0.03 cm2 glassy carbon disc; counter-electrode is a larger platinum plate. The measurements were performed in acetonitrile containing 0.1 M tetraethylammonium tetrafluoroborate relative to the saturated calomel electrode; potential sweep rate 100 mV/s. X-ray Diffraction Study. Single-crystal X-ray diffraction experiments were performed with a Bruker SMART APEX II diffractometer (graphite monochromated Mo Kα radiation, λ = 0.71073 Å, ω-scan technique). The APEX II software21 was used for collecting frames of data, indexing reflections, determination of lattice constants, integration of intensities of reflections, scaling, and absorption correction. All calculations (space group and structure determination, refinements, graphics, and structure reporting) were made using the SHELXL201422

and OLEX223 program packages. Experimental details and crystal parameters are listed in Table S2. The structures were solved by direct methods and refined by the full-matrix least-squares technique against F2 with the anisotropic thermal parameters for all non-hydrogen atoms. Positions of hydrogen atoms were calculated, and all were included in the refinement by the riding model with Uiso(H) = 1.5Ueq(X) for methyl groups and water molecules, and Uiso(H) = 1.2Ueq(X) for other atoms. Crystallographic data for complexes 4 and 17 are presented in Table S2 Supporting Information. DFT Calculation. All calculations with full geometry optimization and normal vibrational mode calculations were performed by the DFTB3LYP/6-31G* and DFT B3LYP/6-311+G* method using a Gaussian-09 program package11 under the operational system Linux. DFT B3LYP/6-31G* and DFT B3LYP/6-311+G* is a combination of the Hartree−Fock method and density functional theory with the use of gradient-corrected functional functional series Becke with three (B3) parameters24,25 and correlation function of a number of Lee-Yang (LYP).26 For every molecule the geometrical position of the atoms was optimized using analytical methods. Normal mode calculations with the use of second derivatives confirm that stationary points obtained from geometry optimization are energetic minima.

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ASSOCIATED CONTENT

S Supporting Information *

The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acs.organomet.9b00165. Additional DFT calculation, cyclicvoltammogram, MS spectra, X-ray data (PDF) Accession Codes

CCDC 1872785−1872786 contain the supplementary crystallographic data for this paper. These data can be obtained free of charge via www.ccdc.cam.ac.uk/data_request/cif, or by emailing [email protected], or by contacting The Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: +44 1223 336033.

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AUTHOR INFORMATION

Corresponding Author

*E-mail: [email protected]. ORCID

Oleg I. Gromov: 0000-0002-4119-8602 Notes

The authors declare no competing financial interest. CCDC 1872785 contains the supplementary crystallographic data for compound 4. CCDC 1872786 contains the supplementary crystallographic data for compound 17.

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ACKNOWLEDGMENTS The authors acknowledge the Russian Science Foundation under Grant No. 17-73-30036 for financial support. REFERENCES

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DOI: 10.1021/acs.organomet.9b00165 Organometallics XXXX, XXX, XXX−XXX