Mercury(II) halide complex of cis-[(tBuNH)(Se)P(μ-NtBu)2P(Se)(NHtBu)]

Selby-Karney, T.; Sampath, K.; Arumugam, K.; Chandrasekaran, C.P.

doi:10.1107/S205698902400937X

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Volume 80| Part 11| November 2024| Pages 1142-1145

https://doi.org/10.1107/S205698902400937X

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Mercury(II) halide complex of cis-[(^tBuNH)(Se)P(μ-N^tBu)₂P(Se)(NH^tBu)]

Troy Selby-Karney,^a Kalpana Sampath,^b Kuppuswamy Arumugam ^b ^* and Chandru P. Chandrasekaran ^a ^*

^aDepartment of Chemistry and Biochemistry, Lamar University, 4400 MLK Blvd., Beaumont, Texas, 77710, USA, and ^bDepartment of Chemistry, Wright State University, 3640 Colonel Glenn Hwy., Dayton, OH 45435, USA
^*Correspondence e-mail: kuppuswamy.arumugam@wright.edu, chandru@lamar.edu

Edited by S. P. Kelley, University of Missouri-Columbia, USA (Received 23 July 2024; accepted 23 September 2024; online 8 October 2024)

The mercury(II) halide complex [1,3-di-tert-butyl-2,4-bis(tert-butylamino)-1,3,2λ⁵,4λ⁵-diazadiphosphetidine-2,4-diselone-κ²Se,Se′]diiodidomercury(II) N,N-dimethylformamide monosolvate, [HgI₂(C₁₆H₃₈N₄P₂Se₂)]·C₃H₇NO or (1)HgI₂, 2, containing cis-[(^tBuNH)(Se)P(μ-N^tBu)₂P(Se)(NH^tBu)] (1) was synthesized and structurally characterized. The crystal structure of 2 confirms the chelation of chalcogen donors to HgI₂ with a natural bite angle of 112.95 (2)°. The coordination geometry around mercury is distorted tetrahedral as indicated by the τ₄ geometry index parameter (τ₄ = 0.90). In the mercury complex, the exocyclic tert-butylamido substituents are arranged in an (endo, endo) fashion, whereas in the free ligand (1), the exocyclic substituents are arranged in an (exo, endo) pattern. Compound 2 displays non-classical N—H⋯O hydrogen-bonding interactions with the solvent N,N-dimethylformamide. These interactions may introduce geometrical distortion and deviation from an ideal geometry. An isostructural HgBr₂ analogue containing cis-[(^tBuNH)(S)P(μ-N^tBu)₂P(S)(NH^tBu)] was also synthesized and structurally characterized, CIF data for the compound being presented as supporting information.

Keywords: crystal structure; cyclodiphosphazanes; mercury(II) halide; tert-butylamido.

CCDC reference: 2386028

1. Chemical context

Stable four-membered rings containing phosphorus and nitrogen with the general formula, [(R)P(μ-N^tBu)₂P(R)] (R = alkyl or aryl), are commonly referred to as cyclodiphosphazanes. They have been used as building blocks to construct interesting macrocycles and polymers (Balakrishna, 2016 ). These macrocycles are formed by taking advantage of the cis orientation of the substituents and the lone pair available on the phosphorus atom (Balakrishna, 2016; Bashall et al., 2002 ). The bis(amido)cyclodiphosphazane and its P^V analogue have been used as a versatile framework to stabilize main-group elements and transition metals (Stahl, 2000 ; Briand et al., 2002 ). The bis(amido)cyclodiphosph(V)azane, cis-{[(R)NH](E)P(μ-N^tBu)₂P(E)[NH(R)]} [E = O, S, Se, N(R); R = alkyl or aryl] and its di-anionic derivatives exhibit three unique coordination modes as shown in Fig. 1. These ligands are capable of bonding to metals and non-metals via (N,N), (E,E) or (N,E) chelation modes. The (N,E) chelation mode is the most frequently observed because of the rigidity and planarity of the four-membered P₂N₂ ring. More importantly, the (N,N) and (E,E) chelation modes demand large bite angles, and large-size metal ions are well suited for these coordination modes. In 2001, Chivers et al. (2001 ) reported (S,S) chelation of cis-[(^tBuN)(S)P(μ-N^tBu)₂P(S)(N^tBu)] to the Pt^II center with a bite angle of 99.57 (13)°. Recently, we have reported (Se,Se) chelation of cis-[(^tBuNH)(Se)P(μ-N^tBu)₂P(Se)(NH^tBu)] by a Pd^II complex with a bite angle of 110.54 (1)° (Bonnette et al., 2018 ). It is evident from these examples that the (E,E) coordination mode prefers large metal cations. Mercury ions have been well documented to have an affinity towards sulfur and selenium atoms, and accounting for its larger size, we set out to explore the coordination chemistry of bis(amido)cyclodiphosph(V)azane ligands with mercury(II) halide. Herein, we report the synthesis and solid-state structure of an HgI₂ coordination complex with cis-[(^tBuNH)(Se)P(μ-N^tBu)₂P(Se)(NH^tBu)] (1), and the results are presented below. An isostructural HgBr₂ analogue was also synthesized and structurally characterized. The CIF data for the compound are presented as supporting information.

Figure 1
Possible coordination modes of bis(amido)cyclodiphosph(V)azanes.

2. Structural commentary

Compound 2 crystallizes in the monoclinic crystal system in space group P2₁/n. The molecular structure of 2 is illustrated in Fig. 2. The crystal structure confirms the chelation of 1 through selenium donors to stabilize the HgI₂ moiety, with an Se1—Hg1—Se2 natural bite angle of 112.95 (2)°. The coordination geometry around the mercury atom is distorted tetrahedral, as indicated by the parameter τ₄ = 0.90. The geometry index τ₄ was developed by Okuniewski and co-workers to distinguish various four-coordinate geometries (Okuniewski et al., 2015 ; Yang et al., 2007 ) with τ₄ = 0 for a square-planar geometry, 0.24 for seesaw, and 1 for a tetrahedral geometry. The Hg—Se [Hg1—Se1 = 2.7508 (5) Å; Hg1–Se2 = 2.7835 (6) Å], and Hg—I [Hg1—I1 = 2.7290 (4) Å; Hg1–I2 = 2.7409 (4) Å] bond distances are within the typical ranges reported for the HgI₂ complexes with selenium ligands (Palmer & Parkin, 2015 ). In complex 2, the P1—Se1 and P2—Se2 bonds [2.1260 (13) and 2.1302 (12) Å, respectively] are slightly elongated compared to the P—Se bond [2.078 (1) Å] in the uncoordinated ligand 1. The four-membered P₂N₂ ring in complex 2 is slightly puckered, as indicated by the angle subtended by the planes N1/P1/N2 and N1/P2/N2 [8.7 (3)°]. The corresponding dihedral angle for the uncoordinated ligand is 3.73 (2)° (Hill et al., 1994 ).

Figure 2
Displacement ellipsoid plot for 2 (50% probability level). The DMF solvent molecule and all the hydrogen atoms are omitted for clarity, except for those at N3 and N4.

3. Supramolecular features

In the crystal of 2, the N—H functional groups present in bis(tert-butylamido)cyclodiphosph(V)azane and oxygen from the DMF solvent molecule are involved in N—H⋯O hydrogen-bonding interactions (Fig. 3, Table 1). Three different conformational isomers are feasible for the cis-bis(amido)cyclodiphosph(V)azane with respect to the relative orientations of the exocyclic nitrogen substituents (Fig. 4). In 2, the exocyclic substituents are arranged in a (endo, endo) fashion, whereas in ligand 1 they are arranged in an (exo, endo) orientation (Hill et al., 1994; Chivers et al., 2002 ). The conformational change in the coordination sphere of 2 may result from the formation of intermolecular interactions. A similar conformational change influenced by hydrogen-bonding interactions has been previously reported (Chandrasekaran et al., 2011 ).

Table 1
Hydrogen-bond geometry (Å, °)

D—H⋯A	D—H	H⋯A	D⋯A	D—H⋯A
N3—H3⋯O1	0.82 (6)	2.18 (6)	2.986 (6)	165 (4)
N4—H4⋯O1	0.79 (5)	2.27 (5)	3.051 (5)	169 (6)

Figure 3
Hydrogen-bonding interactions (Table 1

) between the complex and the DMF solvent molecule in the crystal.

Figure 4
Possible conformational isomers for cis-bis(amido)cyclodiphosph(V)azanes.

4. Database survey

A search of the Cambridge Structural Database (CSD Data, March 2024; Groom et al., 2016 ) gave the following hits for cis-{[(R)_nCN](Se)P[(R)_nN]₂P(Se)[NC(R)_n]}: dichlorido[1,3-di-tert-butyl-2,4-bis(tert-butylamino)-1,3,2,4-diazadiphosphetidine-2,4-diselone-Se,Se']palladium(II)} (Bonnette et al., 2018; CCDC No. 1549758), bis[μ-(2,4-bis(tert-butylamido)-1,3-bis(tert-butyl)-2,4-diseleno-2,4-diphosphetidine)]hexakis(tetrahydrofuran)tetrapotassium, (Chivers et al., 2001; CCDC No. 142628), bis-N,N′,1,3-tetra-tert-butyl-1,3,2,4-diazadiphosphetidine-2,4-diamine 2,4-bis(selenide)]silver(I) trifluoromethanesulfonate (Knight & Woollins, 2016 ; CCDC No. 1042705) and [1,3-di-tert-butyl-2,4-bis(tert-butylamino)-1,3,2,4-diazadiphosphetidine-2,4-diselone]bis(triphenylphosphine)palladium bis(tetrafluoroborate) dichloromethane solvate (Plajer et al., 2020 ; CCDC No. 1890520). The P=Se and P—N bond distances for 2 are in agreement with those in the above compounds.

5. Synthesis and crystallization

Synthesis of cis-[HgI₂(1)] (2):

A dichloromethane (10 mL) solution of cis-[(^tBuHN)(Se)P(μ-^tBuN)₂P(Se)(NH^tBu)] (1) (100 mg, 0.197 mmol) was added dropwise over an acetonitrile (5 mL) solution of HgI₂ (88 mg; 0.197 mmol) under an N₂ atmosphere at ambient temperature. The resulting reaction mixture was stirred for 4 h at 295 K. The solution was then concentrated to nearly 5 mL and stored at 248 K for a day to afford an analytically pure white microcrystalline product. Yield: 91% (172 mg). X-ray quality crystals are obtained by slow evaporation from a DMF solution at room temperature, m.p. 465–467 K. ¹H NMR (400 MHz, DMSO-d₆): 1.44 (s, 18H, ^tBu), 1.58 (s, 18H, ^tBu), 2.58 (br s, 2H, NH). IR (cm⁻¹): 3200 (br w), 2975 (w), 1462 (w), 1388 (w), 1366 (m), 1222 (w), 1183 (m), 1030 (vs), 899 (s), 851 (w), 731 (m), 678 (m). Absorption spectrum [DMSO; λ_max, nm (ɛ_M, M⁻¹ cm⁻¹)]: 270 (13947). Analysis calculated for C₁₆H₃₈N₄P₂Se₂HgI₂: C, 20.00; H, 3.99; N, 5.83. Found: C, 20.26; H, 4.47; N, 5.98.

6. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 2. Methyl (CH₃) hydrogen atoms were treated as a rotating group and added using the riding-model approximation to the carbon atom to which they are attached [C—H = 0.98 Å with U_iso(H) = 1.5U_eq(CH₃).

Table 2
Experimental details

Crystal data
Chemical formula	[HgI₂(C₁₆H₃₈N₄P₂Se₂)]·C₃H₇NO
M_r	1033.85
Crystal system, space group	Monoclinic, P2₁/n
Temperature (K)	300
a, b, c (Å)	9.1747 (8), 17.3698 (13), 20.841 (2)
β (°)	101.049 (3)
V (Å³)	3259.7 (5)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	8.97
Crystal size (mm)	0.53 × 0.28 × 0.26

Data collection
Diffractometer	Bruker SMART X2S
Absorption correction	Multi-scan (SADABS; Krause et al., 2015
T_min, T_max	0.309, 0.746
No. of measured, independent and observed [I > 2σ(I)] reflections	45600, 9576, 6956
R_int	0.077
(sin θ/λ)_max (Å⁻¹)	0.725

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.040, 0.089, 1.00
No. of reflections	9576
No. of parameters	310
H-atom treatment	H atoms treated by a mixture of independent and constrained refinement
Δρ_max, Δρ_min (e Å⁻³)	1.91, −1.92
Computer programs: APEX2 and SAINT (Bruker, 2016 ), SHELXT2018/2 (Sheldrick, 2015a ), SHELXL2019/1 (Sheldrick, 2015b ), Mercury (Macrae et al., 2020 ) and OLEX2 (Dolomanov et al., 2009 ).

7. Data for isostructural HgBr₂ complex

Synthesis and spectroscopic data for an isostructural HgBr₂ with cis-[(^tBuHN)(S)P(μ-^tBuN)₂P(S)(NH^tBu)] are presented below. Spectroscopic analysis and single-crystal structure determination strongly support these are isostructural complexes. For more information regarding solid-state structure determination, please refer to CCDC: 2380829. The CIF data for this compound is available in the supporting information

A dichloromethane (10 mL) solution of cis-[(^tBuHN)(S)P(μ-^tBuN)₂P(S)(NH^tBu)] (1) (100 mg, 0.24 mmol) was added dropwise over an acetonitrile (5 mL) solution of HgBr₂ (87.4 mg; 0.24 mmol) under an N₂ atmosphere at ambient temperature. The resulting reaction mixture was stirred for 4 h at 295 K. The solution was then concentrated to nearly 5 mL and stored at 248 K for a day to afford an analytically pure white microcrystalline product. Yield: 83% (156 mg). X-ray quality crystals were obtained by slow evaporation from DMF solution at room temperature, m.p. 483–485 K. ¹H NMR (400 MHz, DMSO-d₆): 1.45 (s, 18H, ^tBu), 1.59 (s, 18H, ^tBu), 2.54 (br s, 2H, NH). IR (cm⁻¹): 3194 (br m; N-H), 2977 (w), 1471 (w), 1391 (w), 1369 (m), 1225 (w), 1185 (s), 1046 (vs), 907 (m), 852 (m), 745 (s), 705 (m). Absorption spectrum [DMSO; λ_max, nm (ɛ_M, M⁻¹ cm⁻¹)]: 282 (17054). Analysis calculated for C₁₆H₃₈N₄P₂S₂HgBr₂: C, 24.86; H, 4.95; N, 7.25; S, 8.30. Found: C, 25.03; H, 5.08; N, 7.75; S, 8.22.

Supporting information

CCDC reference: 2386028

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S205698902400937X/ev2009sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S205698902400937X/ev2009Isup2.hkl

CIF Data for isomorphous HgBr2 complex. DOI: https://doi.org/10.1107/S205698902400937X/ev2009sup3.txt

checkCIF report

Computing details top

[1,3-Di-tert-butyl-2,4-bis(tert-butylamino)-1,3,2λ⁵,4λ⁵-diazadiphosphetidine-2,4-diselone-κ²Se,Se']diiodidomercury(II) N,N-dimethylformamide monosolvate top

Crystal data top

[HgI₂(C₁₆H₃₈N₄P₂Se₂)]·C₃H₇NO	F(000) = 1944
M_r = 1033.85	D_x = 2.107 Mg m⁻³
Monoclinic, P2₁/n	Mo Kα radiation, λ = 0.71073 Å
a = 9.1747 (8) Å	Cell parameters from 8829 reflections
b = 17.3698 (13) Å	θ = 2.3–26.8°
c = 20.841 (2) Å	µ = 8.97 mm⁻¹
β = 101.049 (3)°	T = 300 K
V = 3259.7 (5) Å³	Prism, colorless
Z = 4	0.53 × 0.28 × 0.26 mm

Data collection top

Bruker SMART X2S diffractometer	6956 reflections with I > 2σ(I)
ω scans	R_int = 0.077
Absorption correction: multi-scan (SADABS; Krause et al., 2015)	θ_max = 31.0°, θ_min = 2.6°
T_min = 0.309, T_max = 0.746	h = −12→13
45600 measured reflections	k = −24→19
9576 independent reflections	l = −28→29

Refinement top

Refinement on F²	Hydrogen site location: mixed
Least-squares matrix: full	H atoms treated by a mixture of independent and constrained refinement
R[F² > 2σ(F²)] = 0.040	w = 1/[σ²(F_o²) + (0.0325P)²] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.089	(Δ/σ)_max = 0.004
S = 1.00	Δρ_max = 1.91 e Å⁻³
9576 reflections	Δρ_min = −1.91 e Å⁻³
310 parameters	Extinction correction: SHELXL2019/1 (Sheldrick, 2015b), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.00052 (5)

Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Hg1	0.70533 (2)	0.77295 (2)	0.58150 (2)	0.02178 (6)
I1	0.60217 (4)	0.91950 (2)	0.55729 (2)	0.02891 (9)
I2	0.90720 (4)	0.72186 (2)	0.50978 (2)	0.02938 (9)
Se1	0.49422 (5)	0.65923 (3)	0.55275 (2)	0.01821 (11)
Se2	0.81087 (5)	0.79005 (3)	0.71512 (2)	0.01874 (11)
P1	0.51042 (12)	0.62623 (6)	0.65210 (6)	0.0119 (2)
P2	0.67826 (12)	0.69810 (6)	0.73987 (6)	0.0120 (2)
N2	0.6846 (4)	0.61881 (19)	0.69491 (18)	0.0131 (8)
N1	0.4974 (4)	0.6991 (2)	0.70322 (19)	0.0127 (7)
O1	0.4763 (4)	0.5489 (2)	0.80940 (19)	0.0317 (9)
N3	0.4072 (4)	0.5541 (2)	0.6635 (2)	0.0164 (8)
H3	0.413 (5)	0.547 (3)	0.703 (3)	0.020*
N4	0.7002 (4)	0.6801 (2)	0.81733 (19)	0.0158 (8)
H4	0.649 (5)	0.644 (3)	0.820 (3)	0.019*
N5	0.3773 (5)	0.4941 (2)	0.8902 (2)	0.0274 (10)
C5	0.8046 (5)	0.5593 (3)	0.6959 (3)	0.0193 (10)
C6	0.7986 (5)	0.5287 (3)	0.6268 (3)	0.0243 (11)
H6A	0.704074	0.504766	0.611382	0.036*
H6B	0.876292	0.491634	0.627173	0.036*
H6C	0.811614	0.570583	0.598316	0.036*
C11	0.4061 (6)	0.4524 (3)	0.5785 (3)	0.0333 (14)
H11A	0.450455	0.488033	0.552709	0.050*
H11B	0.343410	0.417284	0.550175	0.050*
H11C	0.482767	0.424099	0.606659	0.050*
C9	0.3141 (5)	0.4963 (2)	0.6196 (2)	0.0181 (10)
C1	0.3696 (5)	0.7508 (3)	0.7113 (2)	0.0163 (9)
C10	0.1830 (6)	0.5362 (3)	0.5759 (3)	0.0323 (13)
H10A	0.124250	0.562406	0.602559	0.048*
H10B	0.122930	0.498552	0.549292	0.048*
H10C	0.219481	0.572836	0.548227	0.048*
C13	0.7805 (5)	0.7175 (3)	0.8783 (2)	0.0187 (10)
C4	0.4225 (5)	0.8335 (3)	0.7189 (3)	0.0261 (12)
H4A	0.493585	0.838807	0.758917	0.039*
H4B	0.339431	0.866754	0.719846	0.039*
H4C	0.468055	0.847230	0.682688	0.039*
C7	0.9542 (5)	0.5971 (3)	0.7207 (3)	0.0355 (14)
H7A	0.969762	0.637485	0.691327	0.053*
H7B	1.031512	0.559332	0.723061	0.053*
H7C	0.955868	0.618207	0.763393	0.053*
C15	0.9469 (5)	0.7146 (3)	0.8823 (3)	0.0311 (13)
H15A	0.978069	0.662043	0.880656	0.047*
H15B	0.995907	0.737546	0.922644	0.047*
H15C	0.972166	0.742541	0.846240	0.047*
C8	0.7780 (7)	0.4949 (3)	0.7420 (3)	0.0422 (16)
H8A	0.783163	0.515386	0.785149	0.063*
H8B	0.852543	0.455882	0.743044	0.063*
H8C	0.681607	0.472865	0.726814	0.063*
C3	0.2467 (5)	0.7432 (3)	0.6512 (3)	0.0314 (13)
H3A	0.282388	0.760832	0.613343	0.047*
H3B	0.163030	0.773861	0.656945	0.047*
H3C	0.217140	0.690297	0.645353	0.047*
C12	0.2550 (6)	0.4405 (3)	0.6658 (3)	0.0279 (12)
H12A	0.336981	0.416839	0.694597	0.042*
H12B	0.195746	0.401487	0.640602	0.042*
H12C	0.195348	0.468331	0.691109	0.042*
C16	0.7383 (6)	0.6705 (3)	0.9345 (2)	0.0261 (11)
H16A	0.632584	0.671853	0.931349	0.039*
H16B	0.785992	0.692134	0.975582	0.039*
H16C	0.770054	0.618135	0.931728	0.039*
C19	0.3824 (7)	0.4343 (3)	0.9396 (3)	0.0422 (16)
H19A	0.291802	0.405187	0.930901	0.063*
H19B	0.393780	0.457611	0.982021	0.063*
H19C	0.464897	0.400734	0.938354	0.063*
C14	0.7257 (6)	0.8005 (3)	0.8827 (3)	0.0302 (12)
H14A	0.748134	0.829921	0.846829	0.045*
H14B	0.774377	0.823051	0.923183	0.045*
H14C	0.620304	0.800291	0.880742	0.045*
C17	0.4744 (6)	0.4989 (3)	0.8515 (3)	0.0310 (13)
H17	0.548158	0.461504	0.856240	0.037*
C2	0.3118 (6)	0.7242 (3)	0.7719 (3)	0.0269 (12)
H2A	0.281575	0.671275	0.766623	0.040*
H2B	0.228388	0.755317	0.777098	0.040*
H2C	0.389085	0.729280	0.809801	0.040*
C18	0.2577 (8)	0.5492 (4)	0.8855 (4)	0.072 (3)
H18A	0.164600	0.523685	0.870597	0.108*
H18B	0.270631	0.588982	0.855095	0.108*
H18C	0.258555	0.571560	0.927697	0.108*

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Hg1	0.02744 (11)	0.02015 (11)	0.01887 (11)	−0.00093 (7)	0.00728 (8)	0.00364 (8)
I1	0.0387 (2)	0.02087 (18)	0.0257 (2)	0.00404 (14)	0.00268 (15)	0.00612 (14)
I2	0.02607 (17)	0.0364 (2)	0.0285 (2)	−0.00545 (14)	0.01224 (15)	−0.00543 (16)
Se1	0.0244 (2)	0.0215 (2)	0.0084 (2)	−0.00507 (19)	0.00213 (18)	0.00068 (19)
Se2	0.0234 (2)	0.0186 (2)	0.0138 (2)	−0.00661 (18)	0.00253 (19)	0.00001 (19)
P1	0.0155 (5)	0.0115 (5)	0.0088 (6)	−0.0001 (4)	0.0026 (4)	−0.0007 (4)
P2	0.0137 (5)	0.0134 (6)	0.0084 (6)	0.0007 (4)	0.0011 (4)	−0.0003 (5)
N2	0.0138 (17)	0.0145 (19)	0.0106 (19)	0.0040 (14)	0.0015 (15)	−0.0008 (15)
N1	0.0149 (17)	0.0106 (17)	0.012 (2)	0.0012 (14)	0.0005 (15)	−0.0037 (15)
O1	0.040 (2)	0.033 (2)	0.025 (2)	−0.0009 (17)	0.0146 (18)	0.0076 (17)
N3	0.025 (2)	0.016 (2)	0.009 (2)	−0.0055 (16)	0.0064 (17)	−0.0010 (16)
N4	0.023 (2)	0.019 (2)	0.0047 (19)	−0.0072 (16)	0.0006 (15)	0.0008 (16)
N5	0.039 (3)	0.026 (2)	0.018 (2)	−0.0017 (19)	0.008 (2)	0.0066 (19)
C5	0.020 (2)	0.016 (2)	0.023 (3)	0.0082 (18)	0.006 (2)	−0.001 (2)
C6	0.019 (2)	0.025 (3)	0.031 (3)	0.003 (2)	0.010 (2)	−0.013 (2)
C11	0.036 (3)	0.027 (3)	0.041 (4)	−0.010 (2)	0.018 (3)	−0.014 (3)
C9	0.021 (2)	0.014 (2)	0.021 (3)	−0.0110 (18)	0.010 (2)	−0.006 (2)
C1	0.017 (2)	0.015 (2)	0.018 (3)	0.0061 (18)	0.0039 (19)	−0.0005 (19)
C10	0.029 (3)	0.038 (3)	0.029 (3)	−0.013 (2)	0.000 (2)	−0.006 (3)
C13	0.024 (2)	0.028 (3)	0.004 (2)	−0.001 (2)	0.0003 (18)	−0.0053 (19)
C4	0.026 (3)	0.016 (2)	0.039 (4)	0.005 (2)	0.012 (2)	−0.001 (2)
C7	0.023 (3)	0.044 (3)	0.037 (4)	0.007 (2)	−0.001 (2)	−0.017 (3)
C15	0.028 (3)	0.050 (3)	0.015 (3)	−0.003 (2)	0.002 (2)	−0.001 (2)
C8	0.052 (4)	0.031 (3)	0.049 (4)	0.028 (3)	0.023 (3)	0.023 (3)
C3	0.023 (3)	0.036 (3)	0.032 (3)	0.013 (2)	−0.003 (2)	−0.010 (3)
C12	0.037 (3)	0.019 (3)	0.032 (3)	−0.008 (2)	0.017 (3)	0.002 (2)
C16	0.037 (3)	0.031 (3)	0.010 (3)	−0.001 (2)	0.005 (2)	0.003 (2)
C19	0.068 (4)	0.036 (3)	0.022 (3)	−0.008 (3)	0.007 (3)	0.012 (3)
C14	0.043 (3)	0.029 (3)	0.017 (3)	0.000 (2)	0.001 (2)	−0.004 (2)
C17	0.027 (3)	0.034 (3)	0.032 (3)	0.007 (2)	0.007 (2)	0.006 (3)
C2	0.028 (3)	0.029 (3)	0.027 (3)	0.009 (2)	0.013 (2)	0.005 (2)
C18	0.077 (5)	0.085 (6)	0.069 (6)	0.043 (4)	0.050 (5)	0.041 (5)

Geometric parameters (Å, º) top

Hg1—I1	2.7290 (4)	C10—H10B	0.9600
Hg1—I2	2.7409 (4)	C10—H10C	0.9600
Hg1—Se1	2.7508 (5)	C13—C15	1.514 (6)
Hg1—Se2	2.7835 (6)	C13—C16	1.536 (7)
Se1—P1	2.1260 (13)	C13—C14	1.535 (7)
Se2—P2	2.1302 (12)	C4—H4A	0.9600
P1—P2	2.4893 (16)	C4—H4B	0.9600
P1—N2	1.679 (4)	C4—H4C	0.9600
P1—N1	1.674 (4)	C7—H7A	0.9600
P1—N3	1.615 (4)	C7—H7B	0.9600
P2—N2	1.673 (4)	C7—H7C	0.9600
P2—N1	1.689 (4)	C15—H15A	0.9600
P2—N4	1.619 (4)	C15—H15B	0.9600
N2—C5	1.507 (5)	C15—H15C	0.9600
N1—C1	1.511 (5)	C8—H8A	0.9600
O1—C17	1.237 (6)	C8—H8B	0.9600
N3—H3	0.83 (5)	C8—H8C	0.9600
N3—C9	1.508 (6)	C3—H3A	0.9600
N4—H4	0.79 (5)	C3—H3B	0.9600
N4—C13	1.491 (6)	C3—H3C	0.9600
N5—C19	1.457 (6)	C12—H12A	0.9600
N5—C17	1.314 (7)	C12—H12B	0.9600
N5—C18	1.444 (7)	C12—H12C	0.9600
C5—C6	1.526 (7)	C16—H16A	0.9600
C5—C7	1.520 (7)	C16—H16B	0.9600
C5—C8	1.525 (7)	C16—H16C	0.9600
C6—H6A	0.9600	C19—H19A	0.9600
C6—H6B	0.9600	C19—H19B	0.9600
C6—H6C	0.9600	C19—H19C	0.9600
C11—H11A	0.9600	C14—H14A	0.9600
C11—H11B	0.9600	C14—H14B	0.9600
C11—H11C	0.9600	C14—H14C	0.9600
C11—C9	1.519 (6)	C17—H17	0.9300
C9—C10	1.530 (7)	C2—H2A	0.9600
C9—C12	1.536 (6)	C2—H2B	0.9600
C1—C4	1.515 (6)	C2—H2C	0.9600
C1—C3	1.522 (7)	C18—H18A	0.9600
C1—C2	1.531 (7)	C18—H18B	0.9600
C10—H10A	0.9600	C18—H18C	0.9600

I1—Hg1—I2	116.603 (13)	H10A—C10—H10C	109.5
I1—Hg1—Se1	115.134 (15)	H10B—C10—H10C	109.5
I1—Hg1—Se2	97.310 (14)	N4—C13—C15	111.2 (4)
I2—Hg1—Se1	99.784 (14)	N4—C13—C16	105.3 (4)
I2—Hg1—Se2	115.997 (16)	N4—C13—C14	110.2 (4)
Se1—Hg1—Se2	112.950 (15)	C15—C13—C16	109.9 (4)
P1—Se1—Hg1	93.82 (3)	C15—C13—C14	111.4 (4)
P2—Se2—Hg1	93.27 (4)	C14—C13—C16	108.7 (4)
Se1—P1—P2	119.89 (6)	C1—C4—H4A	109.5
N2—P1—Se1	114.83 (14)	C1—C4—H4B	109.5
N2—P1—P2	41.95 (12)	C1—C4—H4C	109.5
N1—P1—Se1	114.57 (14)	H4A—C4—H4B	109.5
N1—P1—P2	42.48 (12)	H4A—C4—H4C	109.5
N1—P1—N2	84.07 (18)	H4B—C4—H4C	109.5
N3—P1—Se1	114.75 (16)	C5—C7—H7A	109.5
N3—P1—P2	125.36 (16)	C5—C7—H7B	109.5
N3—P1—N2	112.8 (2)	C5—C7—H7C	109.5
N3—P1—N1	112.2 (2)	H7A—C7—H7B	109.5
Se2—P2—P1	119.98 (6)	H7A—C7—H7C	109.5
N2—P2—Se2	113.51 (14)	H7B—C7—H7C	109.5
N2—P2—P1	42.15 (12)	C13—C15—H15A	109.5
N2—P2—N1	83.79 (17)	C13—C15—H15B	109.5
N1—P2—Se2	116.10 (14)	C13—C15—H15C	109.5
N1—P2—P1	42.01 (12)	H15A—C15—H15B	109.5
N4—P2—Se2	114.77 (15)	H15A—C15—H15C	109.5
N4—P2—P1	125.25 (15)	H15B—C15—H15C	109.5
N4—P2—N2	112.8 (2)	C5—C8—H8A	109.5
N4—P2—N1	112.1 (2)	C5—C8—H8B	109.5
P2—N2—P1	95.90 (17)	C5—C8—H8C	109.5
C5—N2—P1	132.7 (3)	H8A—C8—H8B	109.5
C5—N2—P2	131.3 (3)	H8A—C8—H8C	109.5
P1—N1—P2	95.51 (18)	H8B—C8—H8C	109.5
C1—N1—P1	132.2 (3)	C1—C3—H3A	109.5
C1—N1—P2	132.2 (3)	C1—C3—H3B	109.5
P1—N3—H3	110 (3)	C1—C3—H3C	109.5
C9—N3—P1	135.0 (3)	H3A—C3—H3B	109.5
C9—N3—H3	115 (3)	H3A—C3—H3C	109.5
P2—N4—H4	105 (4)	H3B—C3—H3C	109.5
C13—N4—P2	135.5 (3)	C9—C12—H12A	109.5
C13—N4—H4	119 (4)	C9—C12—H12B	109.5
C17—N5—C19	123.0 (5)	C9—C12—H12C	109.5
C17—N5—C18	120.8 (5)	H12A—C12—H12B	109.5
C18—N5—C19	116.2 (5)	H12A—C12—H12C	109.5
N2—C5—C6	109.4 (4)	H12B—C12—H12C	109.5
N2—C5—C7	108.6 (4)	C13—C16—H16A	109.5
N2—C5—C8	107.9 (4)	C13—C16—H16B	109.5
C7—C5—C6	109.8 (4)	C13—C16—H16C	109.5
C7—C5—C8	110.2 (5)	H16A—C16—H16B	109.5
C8—C5—C6	111.0 (4)	H16A—C16—H16C	109.5
C5—C6—H6A	109.5	H16B—C16—H16C	109.5
C5—C6—H6B	109.5	N5—C19—H19A	109.5
C5—C6—H6C	109.5	N5—C19—H19B	109.5
H6A—C6—H6B	109.5	N5—C19—H19C	109.5
H6A—C6—H6C	109.5	H19A—C19—H19B	109.5
H6B—C6—H6C	109.5	H19A—C19—H19C	109.5
H11A—C11—H11B	109.5	H19B—C19—H19C	109.5
H11A—C11—H11C	109.5	C13—C14—H14A	109.5
H11B—C11—H11C	109.5	C13—C14—H14B	109.5
C9—C11—H11A	109.5	C13—C14—H14C	109.5
C9—C11—H11B	109.5	H14A—C14—H14B	109.5
C9—C11—H11C	109.5	H14A—C14—H14C	109.5
N3—C9—C11	111.4 (4)	H14B—C14—H14C	109.5
N3—C9—C10	110.4 (4)	O1—C17—N5	125.7 (5)
N3—C9—C12	105.5 (4)	O1—C17—H17	117.2
C11—C9—C10	110.5 (5)	N5—C17—H17	117.2
C11—C9—C12	109.8 (4)	C1—C2—H2A	109.5
C10—C9—C12	109.2 (4)	C1—C2—H2B	109.5
N1—C1—C4	109.5 (4)	C1—C2—H2C	109.5
N1—C1—C3	109.0 (4)	H2A—C2—H2B	109.5
N1—C1—C2	108.1 (4)	H2A—C2—H2C	109.5
C4—C1—C3	109.9 (4)	H2B—C2—H2C	109.5
C4—C1—C2	110.8 (4)	N5—C18—H18A	109.5
C3—C1—C2	109.5 (4)	N5—C18—H18B	109.5
C9—C10—H10A	109.5	N5—C18—H18C	109.5
C9—C10—H10B	109.5	H18A—C18—H18B	109.5
C9—C10—H10C	109.5	H18A—C18—H18C	109.5
H10A—C10—H10B	109.5	H18B—C18—H18C	109.5

Se1—P1—N2—P2	107.86 (15)	P2—N1—C1—C4	40.6 (6)
Se1—P1—N2—C5	−75.0 (4)	P2—N1—C1—C3	160.8 (4)
Se1—P1—N1—P2	−108.19 (15)	P2—N1—C1—C2	−80.2 (5)
Se1—P1—N1—C1	69.0 (4)	P2—N4—C13—C15	−66.1 (6)
Se1—P1—N3—C9	9.6 (5)	P2—N4—C13—C16	175.0 (4)
Se2—P2—N2—P1	−109.36 (14)	P2—N4—C13—C14	58.0 (6)
Se2—P2—N2—C5	73.5 (4)	N2—P1—N1—P2	6.44 (18)
Se2—P2—N1—P1	106.70 (14)	N2—P1—N1—C1	−176.4 (4)
Se2—P2—N1—C1	−70.4 (4)	N2—P1—N3—C9	−124.4 (4)
Se2—P2—N4—C13	7.9 (5)	N2—P2—N1—P1	−6.47 (19)
P1—P2—N2—C5	−177.2 (5)	N2—P2—N1—C1	176.4 (4)
P1—P2—N1—C1	−177.1 (5)	N2—P2—N4—C13	140.0 (4)
P1—P2—N4—C13	−173.4 (4)	N1—P1—N2—P2	−6.51 (19)
P1—N2—C5—C6	36.4 (6)	N1—P1—N2—C5	170.6 (4)
P1—N2—C5—C7	156.1 (4)	N1—P1—N3—C9	142.7 (4)
P1—N2—C5—C8	−84.5 (5)	N1—P2—N2—P1	6.45 (19)
P1—N1—C1—C4	−135.6 (4)	N1—P2—N2—C5	−170.7 (4)
P1—N1—C1—C3	−15.3 (6)	N1—P2—N4—C13	−127.4 (4)
P1—N1—C1—C2	103.6 (5)	N3—P1—N2—P2	−118.1 (2)
P1—N3—C9—C11	57.2 (6)	N3—P1—N2—C5	59.0 (5)
P1—N3—C9—C10	−65.9 (6)	N3—P1—N1—P2	118.7 (2)
P1—N3—C9—C12	176.3 (4)	N3—P1—N1—C1	−64.2 (5)
P2—P1—N2—C5	177.1 (5)	N4—P2—N2—P1	117.9 (2)
P2—P1—N1—C1	177.1 (5)	N4—P2—N2—C5	−59.3 (4)
P2—P1—N3—C9	−170.7 (4)	N4—P2—N1—P1	−118.6 (2)
P2—N2—C5—C6	−147.5 (4)	N4—P2—N1—C1	64.2 (5)
P2—N2—C5—C7	−27.7 (6)	C19—N5—C17—O1	−179.1 (6)
P2—N2—C5—C8	91.7 (5)	C18—N5—C17—O1	0.9 (10)

Hydrogen-bond geometry (Å, º) top

D—H···A	D—H	H···A	D···A	D—H···A
N3—H3···O1	0.82 (6)	2.18 (6)	2.986 (6)	165 (4)
N4—H4···O1	0.79 (5)	2.27 (5)	3.051 (5)	169 (6)

Acknowledgements

The authors would like to acknowledge support by funds from the Chemistry Department, Wright State University, College of Science and Mathematics. The authors would also like to acknowledge Dr Grossie, Wright State University, for help with low-temperature data X-ray diffraction collection.

Funding information

This work is funded in part by the Welch Foundation (V-0004; Chandrasekaran). Funding for this research was provided by: National Institutes of Health, National Cancer Institute (grant No. CA232765 to Kuppuswamy Arumugam); American Chemical Society Petroleum Research Fund (grant No. 59893UR7 to Kuppuswamy Arumugam).

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