Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270107038711/hj3050sup1.cif | |
Structure factor file (CIF format) https://doi.org/10.1107/S0108270107038711/hj3050Isup2.hkl |
CCDC reference: 665481
Hot ethanol solutions of Cu(NO3)2·3H2O and 1,3-bis(diphenylphosphino) propane dioxide were mixed. Slow evaporation of the resulting solution led to the formation of blue–green [pale blue in CIF] crystals.
All H atoms were located from a difference map but were ultimately refined in idealized positions (aromatic C—H = 0.95 Å and methylene C—H = 0.99 Å), constrained to ride on their parent atoms. The H atoms of each functional group were assigned a common refined isotropic displacement parameter; final H-atom displacement parameters were 0.026 (2) Å2 (aromatic H) and 0.022 (4) Å2 (methylene H).
Data collection: COLLECT (Hooft, 1998); cell refinement: DENZO (Otwinowski & Minor, 1997) and COLLECT; data reduction: DENZO and COLLECT; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SNOOPI (Davies, 1983); software used to prepare material for publication: WinGX (Farrugia, 1999) and enCIFer (Allen et al., 2004).
[Cu(NO3)2(C27H26O2P2)] | F(000) = 1300 |
Mr = 631.98 | Dx = 1.451 Mg m−3 |
Orthorhombic, Pbcn | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2n 2ab | Cell parameters from 3747 reflections |
a = 7.9585 (1) Å | θ = 2.9–27.5° |
b = 16.8134 (4) Å | µ = 0.92 mm−1 |
c = 21.6220 (5) Å | T = 120 K |
V = 2893.23 (10) Å3 | Blade, pale blue |
Z = 4 | 0.32 × 0.04 × 0.01 mm |
Bruker–Nonius KappaCCD diffractometer | 3315 independent reflections |
Radiation source: Bruker-Nonius FR591 rotating anode | 2783 reflections with I > 2σ(I) |
10cm confocal mirrors monochromator | Rint = 0.069 |
Detector resolution: 9.091 pixels mm-1 | θmax = 27.5°, θmin = 3.0° |
ϕ and ω scans | h = −10→9 |
Absorption correction: multi-scan (SADABS; Sheldrick, 2003) | k = −21→20 |
Tmin = 0.758, Tmax = 0.991 | l = −28→27 |
25739 measured reflections |
Refinement on F2 | Primary atom site location: heavy-atom method |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.038 | Only H-atom displacement parameters refined |
wR(F2) = 0.082 | w = 1/[σ2(Fo2) + (0.0074P)2 + 4.6738P] where P = (Fo2 + 2Fc2)/3 |
S = 1.05 | (Δ/σ)max = 0.001 |
3315 reflections | Δρmax = 0.45 e Å−3 |
184 parameters | Δρmin = −0.53 e Å−3 |
0 restraints |
[Cu(NO3)2(C27H26O2P2)] | V = 2893.23 (10) Å3 |
Mr = 631.98 | Z = 4 |
Orthorhombic, Pbcn | Mo Kα radiation |
a = 7.9585 (1) Å | µ = 0.92 mm−1 |
b = 16.8134 (4) Å | T = 120 K |
c = 21.6220 (5) Å | 0.32 × 0.04 × 0.01 mm |
Bruker–Nonius KappaCCD diffractometer | 3315 independent reflections |
Absorption correction: multi-scan (SADABS; Sheldrick, 2003) | 2783 reflections with I > 2σ(I) |
Tmin = 0.758, Tmax = 0.991 | Rint = 0.069 |
25739 measured reflections |
R[F2 > 2σ(F2)] = 0.038 | 0 restraints |
wR(F2) = 0.082 | Only H-atom displacement parameters refined |
S = 1.05 | Δρmax = 0.45 e Å−3 |
3315 reflections | Δρmin = −0.53 e Å−3 |
184 parameters |
Experimental. SADABS was used to perform the Absorption correction Parameter refinement on 18376 reflections reduced R(int) from 0.1474 to 0.0584 Ratio of minimum to maximum apparent transmission: 0.76506 The given Tmin and Tmax were generated using the SHELX SIZE command |
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes. |
x | y | z | Uiso*/Ueq | Occ. (<1) | |
Cu1 | 0.5 | 0.29645 (2) | 0.25 | 0.01272 (10) | |
N1 | 0.4265 (2) | 0.38394 (11) | 0.15499 (9) | 0.0178 (4) | |
O1 | 0.33275 (19) | 0.21916 (9) | 0.22756 (7) | 0.0156 (3) | |
O2 | 0.5502 (2) | 0.33970 (10) | 0.14447 (8) | 0.0207 (4) | |
O3 | 0.3617 (2) | 0.38098 (9) | 0.20990 (7) | 0.0183 (3) | |
O4 | 0.3672 (2) | 0.42924 (10) | 0.11622 (8) | 0.0232 (4) | |
P1 | 0.29254 (7) | 0.14981 (3) | 0.18585 (3) | 0.01212 (13) | |
C1 | 0.4729 (3) | 0.09367 (13) | 0.16184 (10) | 0.0146 (5) | |
C2 | 0.6001 (3) | 0.13583 (14) | 0.13181 (10) | 0.0187 (5) | |
H2 | 0.5918 | 0.1919 | 0.1274 | 0.026 (2)* | |
C3 | 0.7387 (3) | 0.09591 (15) | 0.10843 (11) | 0.0224 (5) | |
H3 | 0.825 | 0.1244 | 0.0878 | 0.026 (2)* | |
C4 | 0.7505 (3) | 0.01396 (16) | 0.11541 (12) | 0.0253 (6) | |
H4 | 0.8446 | −0.0136 | 0.0989 | 0.026 (2)* | |
C5 | 0.6263 (3) | −0.02787 (15) | 0.14621 (12) | 0.0242 (5) | |
H5 | 0.6368 | −0.0837 | 0.1516 | 0.026 (2)* | |
C6 | 0.4856 (3) | 0.01174 (14) | 0.16930 (11) | 0.0191 (5) | |
H6 | 0.3993 | −0.017 | 0.1899 | 0.026 (2)* | |
C7 | 0.1942 (3) | 0.18336 (13) | 0.11563 (10) | 0.0150 (5) | |
C8 | 0.1854 (3) | 0.13287 (15) | 0.06447 (11) | 0.0193 (5) | |
H8 | 0.2364 | 0.0818 | 0.066 | 0.026 (2)* | |
C9 | 0.1021 (3) | 0.15735 (16) | 0.01119 (11) | 0.0241 (5) | |
H9 | 0.0959 | 0.123 | −0.0236 | 0.026 (2)* | |
C10 | 0.0282 (3) | 0.23186 (16) | 0.00889 (11) | 0.0253 (6) | |
H10 | −0.0296 | 0.2483 | −0.0274 | 0.026 (2)* | |
C11 | 0.0383 (3) | 0.28245 (16) | 0.05930 (12) | 0.0265 (6) | |
H11 | −0.0113 | 0.3338 | 0.0573 | 0.026 (2)* | |
C12 | 0.1206 (3) | 0.25846 (14) | 0.11267 (11) | 0.0202 (5) | |
H12 | 0.1268 | 0.2932 | 0.1472 | 0.026 (2)* | |
C13 | 0.1429 (3) | 0.08595 (13) | 0.22329 (10) | 0.0144 (4) | |
H13A | 0.0972 | 0.0473 | 0.1931 | 0.022 (4)* | |
H13B | 0.1987 | 0.0559 | 0.2569 | 0.022 (4)* | |
C14 | 0 | 0.13635 (18) | 0.25 | 0.0137 (6) | |
H14A | −0.0455 | 0.171 | 0.217 | 0.022 (4)* | 0.5 |
H14B | 0.0455 | 0.171 | 0.283 | 0.022 (4)* | 0.5 |
U11 | U22 | U33 | U12 | U13 | U23 | |
Cu1 | 0.01308 (19) | 0.01177 (18) | 0.01331 (19) | 0 | −0.00060 (15) | 0 |
N1 | 0.0201 (10) | 0.0144 (9) | 0.0187 (10) | −0.0017 (8) | −0.0014 (8) | 0.0002 (8) |
O1 | 0.0142 (8) | 0.0145 (8) | 0.0182 (8) | −0.0016 (6) | −0.0002 (6) | −0.0029 (6) |
O2 | 0.0215 (8) | 0.0195 (8) | 0.0211 (9) | 0.0059 (7) | 0.0035 (7) | 0.0005 (7) |
O3 | 0.0213 (8) | 0.0183 (8) | 0.0153 (8) | 0.0024 (7) | 0.0021 (6) | 0.0014 (6) |
O4 | 0.0273 (9) | 0.0210 (9) | 0.0211 (9) | 0.0023 (7) | −0.0037 (7) | 0.0080 (7) |
P1 | 0.0106 (3) | 0.0129 (3) | 0.0129 (3) | 0.0003 (2) | 0.0000 (2) | −0.0004 (2) |
C1 | 0.0121 (11) | 0.0181 (11) | 0.0135 (11) | 0.0028 (9) | −0.0014 (8) | −0.0010 (9) |
C2 | 0.0191 (12) | 0.0202 (12) | 0.0167 (12) | 0.0022 (10) | 0.0010 (9) | 0.0030 (9) |
C3 | 0.0153 (11) | 0.0320 (14) | 0.0199 (12) | 0.0005 (10) | 0.0041 (9) | 0.0007 (11) |
C4 | 0.0165 (11) | 0.0347 (15) | 0.0248 (13) | 0.0105 (11) | −0.0005 (10) | −0.0086 (11) |
C5 | 0.0223 (12) | 0.0181 (12) | 0.0322 (14) | 0.0053 (10) | −0.0045 (11) | −0.0085 (10) |
C6 | 0.0174 (11) | 0.0174 (11) | 0.0224 (12) | 0.0009 (10) | −0.0004 (9) | −0.0023 (9) |
C7 | 0.0113 (10) | 0.0191 (11) | 0.0146 (11) | −0.0003 (9) | 0.0008 (8) | 0.0028 (9) |
C8 | 0.0161 (11) | 0.0235 (12) | 0.0181 (11) | 0.0023 (10) | 0.0011 (9) | −0.0019 (10) |
C9 | 0.0230 (13) | 0.0335 (14) | 0.0159 (12) | −0.0019 (11) | −0.0003 (10) | −0.0037 (10) |
C10 | 0.0241 (13) | 0.0363 (15) | 0.0155 (12) | 0.0028 (11) | −0.0041 (10) | 0.0074 (10) |
C11 | 0.0294 (14) | 0.0253 (13) | 0.0248 (13) | 0.0063 (11) | −0.0046 (11) | 0.0054 (11) |
C12 | 0.0216 (12) | 0.0203 (12) | 0.0187 (12) | 0.0008 (10) | −0.0009 (9) | −0.0007 (10) |
C13 | 0.0141 (10) | 0.0153 (11) | 0.0139 (11) | 0.0001 (9) | 0.0007 (8) | 0.0002 (9) |
C14 | 0.0123 (14) | 0.0135 (14) | 0.0154 (15) | 0 | 0.0008 (12) | 0 |
Cu1—O1 | 1.9224 (15) | C4—H4 | 0.9500 |
Cu1—O1i | 1.9224 (15) | C5—C6 | 1.395 (3) |
Cu1—O2i | 2.4279 (16) | C5—H5 | 0.9500 |
Cu1—O2 | 2.4279 (16) | C6—H6 | 0.9500 |
Cu1—O3i | 1.9960 (16) | C7—C8 | 1.396 (3) |
Cu1—O3 | 1.9960 (16) | C7—C12 | 1.394 (3) |
Cu1—N1 | 2.5935 (19) | C8—C9 | 1.392 (3) |
Cu1—P1 | 3.2754 (6) | C8—H8 | 0.9500 |
N1—O2 | 1.254 (2) | C9—C10 | 1.385 (4) |
N1—O3 | 1.296 (2) | C9—H9 | 0.9500 |
N1—O4 | 1.227 (2) | C10—C11 | 1.385 (4) |
P1—O1 | 1.5084 (16) | C10—H10 | 0.9500 |
P1—C1 | 1.795 (2) | C11—C12 | 1.387 (3) |
P1—C7 | 1.799 (2) | C11—H11 | 0.9500 |
P1—C13 | 1.796 (2) | C12—H12 | 0.9500 |
C1—C2 | 1.396 (3) | C13—C14 | 1.532 (3) |
C1—C6 | 1.391 (3) | C13—H13A | 0.9900 |
C2—C3 | 1.386 (3) | C13—H13B | 0.9900 |
C2—H2 | 0.9500 | C14—C13ii | 1.532 (3) |
C3—C4 | 1.389 (4) | C14—H14A | 0.9900 |
C3—H3 | 0.9500 | C14—H14B | 0.9900 |
C4—C5 | 1.384 (4) | ||
O1—Cu1—O1i | 94.95 (9) | C2—C3—H3 | 120.2 |
O1—Cu1—O2 | 94.54 (6) | C4—C3—H3 | 120.2 |
O1—Cu1—O2i | 109.01 (6) | C3—C4—C5 | 120.5 (2) |
O1i—Cu1—O2 | 109.01 (6) | C3—C4—H4 | 119.7 |
O1i—Cu1—O2i | 94.54 (6) | C5—C4—H4 | 119.7 |
O1—Cu1—O3 | 89.41 (6) | C4—C5—C6 | 120.2 (2) |
O1—Cu1—O3i | 166.62 (6) | C4—C5—H5 | 119.9 |
O1i—Cu1—O3 | 166.62 (6) | C6—C5—H5 | 119.9 |
O1i—Cu1—O3i | 89.41 (6) | C1—C6—C5 | 119.3 (2) |
O2—Cu1—O2i | 145.14 (8) | C1—C6—H6 | 120.3 |
O2—Cu1—O3 | 57.94 (6) | C5—C6—H6 | 120.3 |
O2—Cu1—O3i | 95.98 (6) | C8—C7—C12 | 119.6 (2) |
O2i—Cu1—O3 | 95.98 (6) | C7—C8—C9 | 120.0 (2) |
O2i—Cu1—O3i | 57.94 (6) | C7—C8—H8 | 120.0 |
O3—Cu1—O3i | 89.19 (9) | C9—C8—H8 | 120.0 |
O1—Cu1—N1 | 91.57 (6) | C8—C9—C10 | 120.0 (2) |
O1i—Cu1—N1 | 137.68 (6) | C8—C9—H9 | 120.0 |
N1i—Cu1—N1 | 110.89 (8) | C10—C9—H9 | 120.0 |
O2—N1—O3 | 117.12 (18) | C9—C10—C11 | 120.2 (2) |
O2—N1—O4 | 123.10 (19) | C9—C10—H10 | 119.9 |
O3—N1—O4 | 119.77 (19) | C11—C10—H10 | 119.9 |
P1—O1—Cu1 | 145.11 (10) | C10—C11—C12 | 120.2 (2) |
N1—O2—Cu1 | 83.00 (12) | C10—C11—H11 | 119.9 |
N1—O3—Cu1 | 101.87 (12) | C12—C11—H11 | 119.9 |
O1—P1—C1 | 114.19 (9) | C7—C12—C11 | 120.0 (2) |
O1—P1—C7 | 110.77 (10) | C7—C12—H12 | 120.0 |
O1—P1—C13 | 109.47 (10) | C11—C12—H12 | 120.0 |
C1—P1—C7 | 105.59 (10) | C14—C13—P1 | 109.36 (15) |
C1—P1—C13 | 110.25 (10) | C14—C13—H13A | 109.8 |
C7—P1—C13 | 106.23 (10) | C14—C13—H13B | 109.8 |
P1—C1—C2 | 116.58 (17) | P1—C13—H13A | 109.8 |
P1—C1—C6 | 123.06 (17) | P1—C13—H13B | 109.8 |
P1—C7—C8 | 119.99 (17) | H13A—C13—H13B | 108.2 |
P1—C7—C12 | 120.38 (17) | C13—C14—H14A | 109.0 |
C2—C1—C6 | 120.3 (2) | C13ii—C14—H14A | 109.0 |
C1—C2—C3 | 120.0 (2) | C13—C14—H14B | 109.0 |
C1—C2—H2 | 120.0 | C13ii—C14—H14B | 109.0 |
C3—C2—H2 | 120.0 | H14A—C14—H14B | 107.8 |
C2—C3—C4 | 119.6 (2) | C13—C14—C13ii | 112.8 (2) |
Symmetry codes: (i) −x+1, y, −z+1/2; (ii) −x, y, −z+1/2. |
Experimental details
Crystal data | |
Chemical formula | [Cu(NO3)2(C27H26O2P2)] |
Mr | 631.98 |
Crystal system, space group | Orthorhombic, Pbcn |
Temperature (K) | 120 |
a, b, c (Å) | 7.9585 (1), 16.8134 (4), 21.6220 (5) |
V (Å3) | 2893.23 (10) |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 0.92 |
Crystal size (mm) | 0.32 × 0.04 × 0.01 |
Data collection | |
Diffractometer | Bruker–Nonius KappaCCD diffractometer |
Absorption correction | Multi-scan (SADABS; Sheldrick, 2003) |
Tmin, Tmax | 0.758, 0.991 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 25739, 3315, 2783 |
Rint | 0.069 |
(sin θ/λ)max (Å−1) | 0.650 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.038, 0.082, 1.05 |
No. of reflections | 3315 |
No. of parameters | 184 |
H-atom treatment | Only H-atom displacement parameters refined |
Δρmax, Δρmin (e Å−3) | 0.45, −0.53 |
Computer programs: COLLECT (Hooft, 1998), DENZO (Otwinowski & Minor, 1997) and COLLECT, DENZO and COLLECT, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), SNOOPI (Davies, 1983), WinGX (Farrugia, 1999) and enCIFer (Allen et al., 2004).
Cu1—O1 | 1.9224 (15) | N1—O3 | 1.296 (2) |
Cu1—O2 | 2.4279 (16) | N1—O4 | 1.227 (2) |
Cu1—O3 | 1.9960 (16) | P1—O1 | 1.5084 (16) |
Cu1—N1 | 2.5935 (19) | P1—C13 | 1.796 (2) |
Cu1—P1 | 3.2754 (6) | C13—C14 | 1.532 (3) |
N1—O2 | 1.254 (2) | ||
O1—Cu1—O1i | 94.95 (9) | O2—Cu1—O3 | 57.94 (6) |
O1—Cu1—O2 | 94.54 (6) | O2—Cu1—O3i | 95.98 (6) |
O1—Cu1—O2i | 109.01 (6) | O3—Cu1—O3i | 89.19 (9) |
O1—Cu1—O3 | 89.41 (6) | O1—Cu1—N1 | 91.57 (6) |
O1i—Cu1—O3 | 166.62 (6) | O1i—Cu1—N1 | 137.68 (6) |
O2—Cu1—O2i | 145.14 (8) | N1i—Cu1—N1 | 110.89 (8) |
Symmetry code: (i) −x+1, y, −z+1/2. |
Bis(diphenylphosphino)alkane dioxides are capable of coordinating to transition metal ions via monodentate, bidentate chelating or bridging bonding modes. There are examples of 1,1-bis(diphenylphosphino)methane dioxide (dppmO2) acting as both a chelating ligand (Arnáiz et al., 2002) and a bridging ligand (Ding et al., 2000); there are similar examples of 1,2-bis(diphenylphosphino)ethane dioxide (dppeO2) chelating (Povey et al., 1991) and bridging between metal centres (Harding et al., 2007; Yang et al., 2000). Although there are many structural examples of κ2P,P' complexes of 1,3-bis(diphenylphosphino)propane (dppp) with transition metals (Davies et al., 2005; Smith et al., 2003; Morgan et al., 2002), and reports of the catalytic efficacy of 1,3–bis(diphenylphosphino)propane dioxide (dpppO2) (Ogawa et al., 2004), there are few examples of dpppO2 complexes of transition metals. One such complex, MoO2Cl2(dpppO2) (Oh & Mo, 1995), consists of discrete mononuclear units containing a chelating dpppO2 ligand. We report here the structure of a further transition metal complex of dpppO2, the title compound, [Cu(dpppO2)(NO3)2]n, (I) (Fig. 1), prepared as an extension of our work with the bisphosphine dioxide complexes of the lanthanide elements.
The structure of (I) consists of polymeric chains formed by dpppO2 ligands bridging between metal centres. The metal complex is centrosymmetric with the Cu atom sitting on a twofold rotation axis. The coordination geometry about copper is a distorted octahedron with four short [Cu—O(P) = 1.922 (2) Å; Cu–O(N) = 1.996 (2) Å] and two long Cu—O bonds [Cu—O(N) = 2.428 (2) Å]. The distortion from octahedral geometry is attributed to Jahn–Teller distortion, weak intramolecular C—H···O interactions and the small bite angle of the bidentate nitrate ligands [O—Cu—O = 57.94 (6)°]. The geometry may also be described as distorted tetrahedral by considering the nitrate ligands to be bound through a single coordination site. The N···Cu···N angle [110.89 (8)°] supports this description, but the other bond or interatom angles deviate significantly from those of the ideal polyhedron (Table 1).
The PO groups are bound to Cu in a cis conformation. This contrasts with the trans configuration observed in Cu(Ph3PO)2(NO3)2 (Ferrari et al., 1986), but is consistent with the geometry of Ni(Cy3PO)2(NO3)2 (Kennedy et al., 1997). The Cu—O(P) and P—O bond distances are typical for coordinated phosphine oxides, viz. 1.923 (2) and 1.508 (2) Å compared with 1.941 (4) and 1.509 (5) Å in Cu(Ph3PO)2(NO3)2 (Ferrari et al., 1986), and 1.967 (4) and 1.498 (5) Å in [Cu(Ph2PO)2C2H4)Br2]n (Yang et al., 2000). The P—O, P—C and C—C bond lengths in (I) do not differ significantly from those of the chelating dpppO2 ligand in MoO2Cl2(dpppO2) (Oh & Mo, 1995) [1.496 (6)–1.499 (6) Å, 1.80 (1)–1.84 (1) Å and 1.54 (1)–1.56 (1) Å].
The nitrate ligands are bidentate and bound asymmetrically, with Cu—O(N) distances of 1.996 (2) and 2.428 (2) Å, respectively, and this is reflected in the N—O bond lengths [1.296 (2) and 1.254 (2) Å]. The difference between the Cu—O bond lengths [0.432 (3) Å] is similar to that observed in (2-methylpyrazine)copper(II) [0.467 (5) Å; Amaral et al., 2001] and intermediate to that of Cu(Ph3PO)2(NO3)2 [0.232 (8) Å; Ferrari et al., 1986] and[Cu(C5H3N2O2)(NO3)(H2O)]n [0.621 (6) Å; Zheng et al., 2005]. Nitrate groups on adjacent Cu atoms of the polymer are on the same side of the chain (Fig. 2). This contrasts with the dppeO2 complex of CuBr2 (Yang et al., 2000), in which the anionic ligands display an alternating arrangement. The differences in these arrangements are accommodated by the additional C atom in the aliphatic chain of the bridging diphosphonate molecule of (I) and the conformation of the aliphatic chains. In the dppeO2 ligand, the C—C bond exhibits an anti conformation, with the P═O bonds oriented in an antiparallel arrangement. Both C—C bonds of the aliphatic chain of the dpppO2 ligand in (I) also show an anti conformation, but in this case the P═O bonds are arranged to produce an O═P···P═O dihedral angle of 77.7 (1)°. In the complex MoO2Cl2(dpppO2) (Oh & Mo, 1995), both C—C bonds adopt a gauche conformation to accommodate chelation. The free dpppO2 ligand has been reported to crystallize as a hydrate (Calcagno et al., 2000) in which the dpppO2 molecule does not exhibit the twofold rotational symmetry observed in (I). In the structure of the hydrate, the alkyl chain of the hydrogen-bonded dpppO2 molecule consists of one anti C—C bond and one gauche C—C bond, shifting the orientation of the P═O bonds towards the more favourable antiparallel alignment.
Although there are no classical hydrogen bonds in the structure of (I), there are a number of intramolecular and intermolecular short contacts, indicating weak C—H···O and C—H···π interactions, which may stabilize ligand conformation and regulate crystal packing. In the structure of (I), two intramolecular C–H···π interactions serve to stabilize the parallel alignment of ligands within the polymer chain. These consist of methylene–phenyl and phenyl–phenyl (edge-to-face) C—H···π interactions with H···π(centroid) distances of 2.71 and 2.73 Å, respectively. In the first of these interactions, methylene atom C13 acts as a donor, via atom H13B, to the C1–C6 ring at (1 − x, y, 1/2 − z), and in the second interaction, phenyl atom C3 acts as a donor, via atom H3, to the C7–C12 ring at (1 + x, y, z). The observed H···π(centroid) distances are appreciably shorter than those reported for similar interactions in a series of free and solvated alkyl bis(diphenylphosphine oxides) (2.95–3.65 Å; Calcagno et al., 2000).
Intramolecular C—H···O interactions between phenyl CH groups and coordinated O atoms influence the asymmetry of the bidentate nitrate ligands, in that the C—H···O interaction corresponds to the O atom with the longer Cu—O bond. Phenyl atom C2 acts as a hydrogen-bond donor, via atom H2, to atom O2 within the same asymmetric unit. The C···O distance, 3.462 (3) Å, is shorter and the C—H···O angle, 165°, is smaller than the ranges reported for structures of alkyl bis(diphenylphosphine oxides) (3.52–3.60 Å and 169–175°; Calcagno et al., 2000). Further C–H···O interactions exist between polymer chains; two phenyl C–H···O interactions [C4—H4···O4(- x + 3/2, y − 1/2, z): 3.360 (3) Å and 148°; C9—H9···O2(x − 1/2, −y + 1/2, −z): 3.391 (3) Å and 129°] and one methylene C—H···O interaction [C13—H13A···O4(−x + 1/2, y − 1/2, z): 3.508 (3) Å and 152°] provide a link between the nitrate groups of one polymeric chain and two further chains. The C···O distances and C—H···O angles in (I) all fall within accepted ranges for this type of interaction (3.0–4.0 Å and 90–180°; Desiraju, 1991).