黑土稻田CH4与N2O排放及减排措施研究

通过对黑土稻田CH₄和N₂O排放的观测,发现水稻生长季CH₄和N₂O排放量低于全国其它地区稻田CH₄和N₂O排放之间存在互为消长关系(r=-0．513,P<0．05),但在同样施肥水平条件下,间歇灌溉与长期淹灌相比,CH₄排放明显减少而N₂O略有增加,其相对综合温室效应被大大减少且水稻产量未受影响。为此,间歇灌溉可作为减少稻田温室气体排放的水分管理措施。另外,通过对CH₄和N₂O排放的相关微生物过程探讨,揭示产甲烷菌数与CH4排放问呈显著性正相关(R²=0．82,P<0．05),硝化菌数和反硝化菌数与N2O排放有重要关系。     

黄河上游灌区稻田N2O排放特征

黄河上游灌区稻田高产区过量施肥现象十分突出,氮肥过量施用引起土壤氮素盈余,导致N₂O排放量增大,由此引起的温室效应引起广泛关注。采用静态箱-气相色谱法研究黄河上游灌区稻田不同施肥处理下N₂O排放特征。试验设置5个施肥处理,包括常规氮肥300 kg/hm²下单施尿素和有机肥配施2个处理,分别用N300和N300-OM代表;优化氮肥240 kg/hm²下单施尿素和有机肥配施2个处理,分别用N240和N240-OM代表;对照不施氮肥用N0代表。试验结果得出,灌区水稻生长季稻田土壤N₂O排放主要集中在水稻分蘖前及水稻生长的中后期,稻田氮肥施用、灌水及土壤温度的变化对N₂O排放通量影响较大,不同处理水稻各生育阶段N₂O累积排放量与稻田土壤耕层NO^-₃-N含量动态变化显著相关。稻田N₂O排放不是黄河上游灌区稻田氮素损失的主要途径,但灌区稻田N₂O排放的增温潜势较大;稻田氮肥过量施用会显著增加N₂O排放量,在相同氮素水平下,有机肥配施会显著增加稻田土壤N₂O的排放量(P＜0.01)。优化施氮能有效减少灌区稻田水稻生长季N₂O排放量。稻田不同处理的水稻整个生长季土壤N₂O排放总量为2.69-3.87 kg/hm²,肥料氮通过N₂O排放损失的百分率仅为0.43%-0.64%。在灌区习惯灌水和高氮肥300 kg/hm²时,N300-OM处理的稻田N₂O排放量达3.87 kg/hm²,在100 a时间尺度上的全球增温潜势(GWPs)为20.76×10⁷ kg CO₂/hm²;优化施氮240 kg/hm²水平下,N240和N240-OM处理的N₂O累计排放量较N300-OM处理,分别降低了1.18 kg/hm²和0.57 kg/hm²,在100 a尺度上每年由稻田N₂O排放引起的GWPs分别降低了6.33×10⁷ kg CO₂/hm²和3.06×10⁷ kg CO₂/hm²。     

双季稻田种植不同冬季作物对甲烷和氧化亚氮排放的影响

研究双季稻收获后填闲种植不同冬季作物在其生长季节内CH₄和N₂O的排放特征,对合理利用冬闲稻田,发展冬季作物生产及合理评价不同种植模式具有重要意义。采用静态箱-气相色谱法对冬季免耕直播黑麦草、紫云英、油菜以及翻耕移栽油菜和冬闲的双季稻田中甲烷(CH₄)和氧化亚氮(N₂O)排放进行了分析。结果表明:在冬季作物生长期,CH₄、N₂O平均排放通量和总排放量均表现为翻耕移栽油菜＞免耕直播黑麦草＞免耕直播油菜＞免耕直播紫云英＞冬闲。不同冬季作物稻田CH₄和N₂O总排放量与对照(冬闲)的差异均达到极显著水平(P<0.01);翻耕移栽油菜的双季稻田中CH₄和N₂O排放量最高,分别达2.989 g/m²和0.719 g/m²。翻耕移栽油菜稻田的CH₄和N₂O温室效应总和也最大,为2893.92 kg CO₂/hm²;免耕直播黑麦草和免耕直播油菜处理次之,而免耕直播紫云英处理最低。种植不同冬季作物促进了稻田生态系统CH₄和N₂O的排放。     

太湖流域农田稻季CH4通量特征及影响因子

开展太湖流域农田稻季CH₄排放研究,深入了解稻田CH₄排放规律,为稻田CH₄减排、制定合理稻田管理措施提供科学依据。以太湖流域稻麦轮作农田为研究区域,运用涡度相关法观测其稻季CH₄通量变化,分析其通量变化特征及影响因子。结果表明：太湖流域典型稻麦轮作区稻季为CH₄的源,CH₄排放总量为28.95 g/m²,稻季CH₄通量日变化表现为无规则型与单峰型两种模式;稻季CH₄排放整体集中在水稻生长前期（81.61%）及中期（16.16%）、后期排放相对较弱（2.23%）,返青期排放量较低（日均0.102 μmol m^-2 s^-1）,分蘖期较强（日均0.451 μmol m^-2 s^-1）,成熟期最低（日均0.006 μmol m^-2 s^-1）;模型所模拟的累计CH₄排放通量比累计测量CH₄通量低6.69%,较好地模拟了太湖流域稻田CH₄的排放,土壤温度、土壤水分、土壤电导率、摩擦风速可确认为太湖流域农田稻季CH₄排放的主要驱动因子。     

施硅对增温稻田CH4和N2O排放的影响

夜间增温幅度大于白天是气候变暖的显著特征。夜间增温影响水稻生产及CH4和N2O排放。硅是作物有益元素,施硅可提高产量,减少稻田CH4排放。增温或施硅单因子对稻田CH4和N2O排放影响已有报道,但二者耦合如何影响水稻生产及稻田CH4和N2O排放,尚不清楚。通过田间模拟试验,研究了夜间增温下施硅对水稻生长、产量及温室气体持续增温/冷却潜势和排放强度的影响。采用铝箔反光膜夜间(19:00-6:00)覆盖水稻冠层进行模拟夜间增温试验。增温设2水平,即常温对照(CK)和夜间增温(NW);施硅量设2水平,即Si0(不施硅)和Si1(钢渣硅肥,200 kgSiO2/ha)。结果表明,施硅可缓解夜间增温对水稻根系活力的抑制作用,降低夜间增温对水稻地上部、地下部干重和产量的抑制作用。夜间增温显著提高CH4累计排放量,而施硅显著降低CH4累计排放量。夜间增温下施硅处理稻田CH4累计排放量在分蘖期、拔节期、抽穗-扬花期和灌浆成熟期比未施硅处理分别低48.12%、49.16%、61.59%和39.13%。夜间增温或施硅均促进稻田N2O排放,夜间增温下施硅在上述生育期以及全生育期的累计排放量依次比对照高78.17%、51.45%、52.01%、26.14%和40.70%。研究认为,施硅可缓解夜间增温对稻田综合增温潜势和排放强度的促进作用。     

川中丘陵区冬灌田甲烷和氧化亚氮排放研究

采用静态暗箱/气相色谱法对川中丘陵区冬灌田CH₄和N₂O排放特征进行连续一年的田间原位测定.结果表明,种植水稻区(种植区)在水稻生长季平均CH₄排放速率为22.76±2.76 mg·m^-2·h^-1,休闲期平均为1.43±0.20 mg·m^-2·h^-1,全年平均为9.64±1.17 mg·m^-2·h^-1;全年CH₄排放主要集中在水稻生长季,其累计CH₄排放量占全年总CH₄排放量的91.2%未种植水稻区(对照区) 全年CH₄平均排放速率为2.03±0.18 mg·m^-2·h^-1,水稻生长季CH₄排放量占全年总排放量的86.2%.N₂O的排放在稻田落干时呈现脉冲排放.在水稻生长季,对照区CH₄和N₂O的季节排放速率分别为4.53±0.38mg·m^-2·h^-1和32.01±5.02 μg·m^-2·h^-1,而种植区则分别为22.76±2.76 mg·m^-2·h^-1和73.04±5.03 μg·m^-2·h^-1,植株参与导致CH₄和N₂O排放速率分别增加302%和128%.CH₄和N₂O的排放随土水分条件的变化呈互为消长关系.在冬灌田中,即使考虑500年的时间尺度,全年N₂O排放产生的全球增温潜势也只有CH₄的7.9%,与CH₄相比,冬灌田排放的N₂O所产生的温室效应很小.     

城市化地区典型水体的N2O排放通量特征——以南京市为例

内陆淡水水体是大气中N₂O的重要排放源,然而目前对于内陆典型城市水体N₂O排放通量的监测数据依然匮乏,典型城市水体的N₂O排放特征及驱动因素尚不清楚。本研究选取了南京市江北新区的典型水体,包括湖库、河流、养殖池塘和景观池塘,在2020年5月-2021年4月利用漂浮箱法连续监测了不同水体类型的水-气界面N₂O排放特征,并通过测定水环境特征,探究驱动水体N₂O排放通量的关键因素。研究结果表明,典型城市水体整体均表现为N₂O排放源,河流和养殖池塘的日平均排放通量最大,分别为（503±1236）μg m^-2 d^-1和（508±797）μg m^-2 d^-1,其次为景观池塘（（179±989）μg m^-2 d^-1）,而湖库的N₂O排放通量最小,仅表现为微弱的N₂O排放源（（54±212）μg m^-2 d^-1）。水体的N₂O排放呈现季节性差异,河流和养殖池塘夏季的N₂O排放通量显著高于其他季节（P<0.01）。水体全年N₂O排放数据与水体温度和溶解氧含量（DO）呈显著相关。而在温度较高的5月份-9月份（>20℃）,氮输入成为影响N₂O排放通量的关键因素（P<0.01）,因此控制城市水体的氮输入尤其是在水温较高的夏季是减少N₂O排放的有利措施。此外,由于水文化学条件差异等因素,小型封闭水体包括养殖池塘和景观池塘的N₂O排放通量差异较大,未来应加强监测不同水体的水文化学特征和N₂O的时空排放特征,探讨影响小型封闭水体水-气界面N₂O排放通量的具体驱动因素。此研究为城市区域N₂O排放的精准核算提供了数据支撑,为N₂O排放模型的修正提供了科学依据。     

火干扰对小兴安岭落叶松-苔草沼泽温室气体排放的影响

利用静态箱-气相色谱法,研究火烧干扰(轻度、重度)对小兴安岭落叶松-苔草沼泽生长季CO₂、CH₄、N₂O排放的影响.结果表明:火烧干扰使CO₂排放通量提高24.0%-45.9%, CH₄提高135.1%(轻度)或下降31.3%(重度),N₂O由吸收转化为排放.重度火烧改变了CO₂的季节排放规律,火干扰改变了CH₄与N₂O的季节排放规律.火烧与未火烧样地CO₂排放与水位呈显著负相关,与空气温度、土壤温度呈显著正相关;未火烧样地CH₄排放与水位呈显著负相关,与地表温度呈显著正相关,轻度火烧样地CH₄排放与气温和个别土壤温度呈显著正相关,而重度火烧样地CH₄排放、各样地的N₂O排放与水位和温度相关性均不显著.火干扰使CO₂排放源强度较未火烧提高,轻度火烧样地CH₄排放源强度较未火烧提高、重度样地则下降;N₂O则由吸收汇转化为排放源.火烧样地温室效应贡献潜力较未火烧样地提高了1/4-1/2,且呈现出随火干扰强度增大而递增的变化规律\.     

外源氮对沼泽湿地CH4和N2O通量的影响

三江平原沼泽湿地受到大气沉降、地表径流、农业排水等外源氮素的输入,对湿地生态系统CH₄和N₂O通量有重要影响。采用野外原位施肥试验模拟外源氮输入,设0,60,120,240kgN•hm^-2 4种试验处理,探讨外源氮对沼泽湿地CH₄和N₂O通量的影响。结果表明,外源氮促进了CH₄和N₂O排放。与对照处理比较,各施氮水平CH₄平均排放通量分别增加了181％,254％和155％,N2O排放通量分别增加了21％,100％和533％。外源氮输入对CH₄排放的季节变化形式影响不大,而N²O的季节变化形式随着氮输入表现出波动变化的趋势。不同施氮水平对CH₄排放的促进作用与植物生长阶段和产CH₄的微生物过程密切相关,N₂O排放通量随氮输入量呈指数增加（R²＝0.97,p<0.01）。外源氮通过影响湿地微生物过程来进一步影响CH₄和N₂O的排放。     

黄土高原冬小麦地N2O排放

从2007年7月1日到2009年6月30日对黄土高原冬小麦地氧化亚氮(N₂O)排放采用静态箱气相色谱法进行了为期2a 的监测。设置2个处理,有小麦田(有小麦生长),无小麦田(出芽初期拔去麦苗)。研究结果表明有小麦田、无小麦田N₂O排放量年际变化不大。有小麦田年均的N₂O 排放量为2.05 kg · N₂O · hm^-2 · a^-1,无小麦田年均的N₂O 排放量为2.28 kg · N₂O · hm^-2 · a^-1 。在冻融交替期,施肥后、翻地后和降雨后无小麦田和有小麦田N₂O排放明显增加,N₂O的季节变化受到这些短期事件的显著影响;有小麦田N₂O排放与地温(P<0.01),气温(P<0.01)和WFPS(P<0.05)显著相关,而无小麦田N₂O排放与这些环境土壤因子都不相关;有小麦田和无小麦田两个处理土壤的WFPS通常都低于60%,可以推断在本地区,硝化反应是N₂O的重要生成源。     

Solution-mediated syntheses and characterizations of two new zincophosphites [C6H14N2]0.5[Zn(H2PO3)2] and [C4H12N2]0.5[(CH3)2NH2][Zn2(HPO3)3]

Two new zincophosphites [C₆H₁₄N₂]_0.5[Zn(H₂PO₃)₂] 1 and [C₄H₁₂N₂]_0.5[(CH₃)₂NH₂][Zn₂(HPO₃)₃] 2 have been solvothermally synthesized in mixed solvents of N,N-dimethylformamide (DMF) and 1,4-dioxane (DOA), respectively. Single-crystal X-ray diffraction analysis reveals that compound 1 exhibits a neutral inorganic chain formed by ZnO₄ and HPO₂(OH) units. Interestingly, the left- and right-handed hydrogen-bonded helical chains are alternately formed via the hydrogen-bonds between two adjacent chains. Compound 2 exhibits a layer structure with 4- and 12-MRs formed by ZnO₄ and HPO₃ units, in which two kinds of organic amine molecules both act as countercations to compensate the overall negative electrostatic charge of the anionic network.     

p-Quinquephenyl diamine, C6H5-p-C6H4-p-C6H2(2,3-NH2)-p-C6H4-C6H5, and its corresponding diimine-Ru(II) complex: Crystal structure and electrochemical and optical properties

The molecular structure of an o-phenylenediamine unit-containing oligophenylene (1), Ph-Ph′-Ph′(2,3-NH₂)-Ph′-Ph (Ph = phenyl; Ph′ = p-phenylene; Ph′(2,3-NH₂) = 2,3-diamino-p-phenylene), was determined by X-ray crystallography. 1 has a twisted structure, and forms an intermolecular C-H?π interaction network. The -NH₂ group of 1 was air-oxidized to an imine, NH, group in the presence of [RuCl₂(bpy)₂] (bpy = 2,2′-bipyridyl) and gave a ruthenium(II)-benzoquinone diimine complex [Ru(2)(bpy)₂](PF₆)₂ (2: Ph-Ph′-Ph′(2,3-imine)-Ph′-Ph). The molecular structure of [Ru(2)(bpy)₂](PF₆)₂ was confirmed by X-ray crystallography. [Ru(2)(bpy)₂](PF₆)₂ underwent two-step electrochemical reduction with E^1/2 = −0.889 V and −1.531 V versus Fc⁺/Fc. The E^1/2’s were located at higher potentials by 91 mV and 117 mV, respectively, than those of reported [Ru(bqdi)(bpy)₂](PF₆)₂ (bqdi = benzoquinone diimine). Electrochemical oxidation of [Ru(2)(bpy)₂](PF₆)₂ occurred at a lower potential by 180 mV than that of [Ru(bqdi)(bpy)₂](PF₆)₂. Occurrence of the easier reduction and oxidation of [Ru(2)(bpy)₂](PF₆)₂ than those of [Ru(bqdi)(bpy)₂](PF₆)₂ is ascribed to the presence of a large π-conjugation system in 2.     

New preparations and molecular structures of cis-MCl2(Ph2PCH2PPh2)2, M = Ru,Os and trans-RuCl2(Ph2PCH2PPh2)2

The title compounds were made by reacting bis(diphenylphosphino)methane (dppm) with reduced solutions of OsCl₆^4? and Ru₂OCl₁₀^4?. The crystal and molecular structures of these compounds have been determined form three-dimensional X-ray study. The cis-isomers crystallize with one CHCl₃ per molecule of the complex. All three compounds crystallize in the monoclinic space group P2₁/n with unit cell dimensions as follows: Cis-OsCl₂(dppm)₂·CHCl₃: a = 13.415(4) Å, b = 22.859(4) Å, c = 16.693(3) Å, β = 105.77(3)°, V = 4926(3) ų, Z = 4. cis-RuCl₂(dppm)₂·CHCl₃: a = 13.442(3) Å, b = 22.833(7) Å, c = 16.750(4) Å, β = 105.53(2)°, V = 4953(3) ų, Z = 4. trans-RuCl₂(dppm)₂: a = 11.368(7) Å, b = 10.656(6) Å, c = 18.832(12) Å; β = 103.90(6)°, V = 2213(7) ų; Z = 2. The structures were refined to R = 0.044 (R_w = 0.055) for cis-OsCl₂(dppm)₂·CHCl₃; R = 0.065 (R_w = 0.079) for cis-RuCl₂(dppm)₂·CHCl₃ and R = 0.028 (R_w = 0.038) for trans-RuCl₂(dppm)₂. The complexes are six coordinate with stable four-membered chelate rings. The PMP angle in the chelate rings is ca. 71° in each case.     

Synthesis of tantalum and niobium complexes that contain the diamidoamine ligand, [(3,4,5-F3C6H2NCH2CH2)2NMe], and the triamidoamine ligand, [(3,5-Cl2C6H3NCH2CH2)3N]

Several niobium and tantalum compounds were prepared that contain either the diamidoamine ligand, [(3,4,5-F₃C₆H₂NCH₂CH₂)₂NMe]²⁻ ([F₃N₂NMe]²⁻), or the triamidoamine ligand, [(3,5-Cl₂C₆H₃NCH₂CH₂)₃N]³⁻ ([Cl₂N₂NMe]³⁻). The former include [F₃N₂NMe]TaCl₃, [F₃N₂NMe]NbCl₃, [F₃N₂NMe]TaMe₃, [F₃N₂NMe]NbMe₃, [(F₃N₂NMe)TaMe₂][MeB(C₆F₅)₃], [F₃N₂NMe]Ta(CHSiMe₃)(CH₂SiMe₃), [F₃N₂NMe]Ta(CH₂-t-Bu)Cl₂, [F₃N₂NMe]Ta(CH-t-Bu)(CH₃), and [F₃N₂NMe]Ta(η²-C₂H₄)(CH₂CH₃). The latter include [Cl₂N₂NMe]TaCl₂, [Cl₂N₂NMe]TaMe₂, [Cl₂N₂NMe]Ta(η²-C₂H₄), and [Cl₂N₂NMe]Ta(η²-C₂H₂).X-ray diffraction studies were carried out on [F₃N₂NMe]Ta(CHSiMe₃)(CH₂SiMe₃), [F₃N₂NMe]Ta(η²-C₂H₄)(CH₂CH₃), and [Cl₂N₂NMe]TaMe_2..     

Synthesis and crystal structure of the MgCl2(CH3COOC2H5)2· (CH3COOC2H5) adduct

The reaction of α-MgCl₂ with boiling ethyl acetate affords MgCI₂(CH₃COOC₂H₅)₂· (CH₃COOC₂H₅), which is obtained as crystals suitable for X-ray analysis only from the mother liquor. M=315.5, orthorhombic, space group P2₁22₁ (No. 18), a=25.077(3), b=8.616(1), c=7.345(1) Å, V=1587.0(3) ų, Z=4, D_x=1.32 g cm⁻³,λ A(Mo Kα)=0.71069 Å, μ=4.17 cm⁻¹, F(000)=664, T=298 K, observed reflections: 1667, R=0.059 and R_w=0.069. The structure is composed of polymeric chains of MgCl₂(CH₃COOC₂H₅₎₂ and the ethyl acetate molecules occupy a mutually trans position.     

Selective synthesis of triangular cluster oxido-sulfidocomplexes of Mo and W: High yield preparations of [Mo3O2S2(H2O)9], [W3O2S2(H2O)9], [W2MoO2S2(H2O)9] and their derivatization

Reaction of [Mo₂O₂(μ-S)₂(H₂O)₆]²⁺ with Mo(CO)₆ or metallic Mo under hydrothermal conditions (140 °C, 4 M HCl) gives oxido-sulfido cluster aqua complex [Mo₃(μ₃-S)(μ-O)₂(μ-S)(H₂O)₉]⁴⁺ (1). Similarly, [W₃(μ₃-S)(μ-O)₂(μ-S)(H₂O)₉]⁴⁺ (2) is obtained from [W₂O₂(μ-S)₂(H₂O)₆]²⁺ and W(CO)₆. While reaction of [Mo₂O₂(μ-S)₂(H₂O)₆]²⁺ with W(CO)₆ mainly proceeds as simple reduction to give 1, [W₂O₂(μ-S)₂(H₂O)₆]²⁺ with Mo(CO)₆ produces new mixed-metal cluster [W₂Mo(μ₃-S)(μ-O)₂(μ-S)(H₂O)₉]⁴⁺ (3) as main product. From solutions of 1 in HCl supramolecular adduct with cucurbit[6]uril (CB[6]) {[Mo₃O₂S₂(H₂O)₆Cl₃]₂CB[6]}Cl₂⋅18H₂O (4) was isolated and structurally characterized. The aqua complexes were converted into acetylacetonates [M₃O₂S₂(acac)₃(py)₃]PF₆ (M₃ = Mo₃, W₃, W₂Mo; 5a-c), which were characterized by X-ray single crystal analysis, electrospray ionization mass spectrometry and ¹H NMR spectroscopy. Crystal structure of (H₅O₂)(Me₄N)₄[W₃(μ₃-S)(μ₂-S)(μ₂-O)₂(NCS)₉] (6), obtained from 2, is also reported.     

Hydrothermal synthesis and structure of an open framework Co0.7Zn1.3(PO4)2(NH3-CH2CH2NH3) and Co6.2(OH)4(PO4)4Zn1.80, a new adamite type phase

The hydrothermal reaction of cobalt(II)oxalate di-hydrate, zinc oxide, and triethyl-orthophosphate, using 1,2-diaminoethane as structure directing template in water, produced two major crystal phases in almost equal amount: the purple crystals of [NH₃-CH₂CH₂NH₃][Co_0.7Zn_1.3(PO₄)₂] (1) and the red burgundy crystals of Co_6.2(OH)₄(PO₄)₄Zn_1.80 (2), a new adamite type phase. The structure of [NH₃-CH₂CH₂NH₃] [Co_0.7Zn_1.3(PO₄)₂] (1) exhibits a 3D open framework built from PO₄ and (Co/Zn)O₄ tetrahedra, and (Co/Zn)O₅ trigonal bipyramids, forming two major channels, an 8-membered ring channel and a 16-membered ring channel, that host the ethanediammonium ions. The Co_6.2(OH)₄(PO₄)₄Zn_1.80 (2) is isomorphous with adamite-type M₂(OH)XO₄ structure, with a condensed vertex and edge sharing network of (Co/Zn)O₅, and distorted CoO₆, and PO₄ subunits. The cobalt preference for higher coordination numbers is displayed in this structure, where the octahedral sites are wholly occupied by cobalt. Thermal analysis confirmed that these compounds display high thermal stability.     

Crystal structures of MoCl2(O)(O2)(OPMePh2)2 and mixtures of MoCl2(O2)(OPPh3)2 and MoCl2(O)(O2)(OPPh3)2: allylic alcohol isomerization studies using MoCl2(O)(O2)(OPMePh2)2

Adding one equivalent of H₂O₂ to compounds of stoichiometry MoCl₂(O)₂(OPR₃)₂, OPR₃ = OPMePh₂ or OPPh₃, leads to the formation of oxo-peroxo compounds MoCl₂(O)(O₂)(OPR₃)₂. The compound MoCl₂(O)(O₂)(OPMePh₂)₂ crystallized with an unequal disorder, 63%:37%, between the oxo and peroxo ligands, as verified by single-crystal X-ray diffractometry, and can be isolated in reasonable yields. MoCl₂(O)(O₂)(OPPh₃)₂, was not isolated in pure form, co-crystallized with MoCl₂(O)₂(OPPh₃)₂ in two ratios, 18%:82% and 12%:88%, respectively, and did not contain any disorder in the arrangement of the oxo and peroxo groups. These complexes accomplish the isomerization of various allylic alcohols. A mechanism of this reaction has been constructed based on ¹⁸O isotopic studies and involves exchange between the alcohol and metal bonded O atoms.     

Metal-organophosphonates: hydrothermal synthesis and structures of [Cu(O3PC10H6CO2H)] and [Cu(bpy)(HO3PC10H6CO2)] (H2O3PC10H6CO2H = 2,6-carboxynaphthalene phosphonic acid)

Hydrothermal methods were used to prepare [Cu(O₃PC₁₀H₆CO₂H)] (1) and [Cu(bpy)(HO₃PC₁₀H₆CO₂)]·2H₂O (2·2H₂O), where H₂O₃PC₁₀H₆CO₂H is 2,6-carboxynaphthalene phosphonic acid (H₃cnp). The two-dimensional structure of 1 consists of layers of edge-sharing {CuO₆} octahedra, producing an AlCl₃- type structure of fused hexagonal rings of copper octahedra, enclosing voids of hexagonal profile. The layer composition is CuO₃ or CuO₆/₂ as each oxygen bridges two copper sites. The Hcnp ligands project from either face of the copper “oxide” layer. Adjacent layers interact through hydrogen bonding interactions between the pendant -CO₂H groups of the ligand. Coordination of the bipyridine ligand in [Cu(HO₃PC₁₀H₆CO₂)] (2) obstructs expansion in two-dimensions, and the material exhibits a chain structure. The chain is constructed of binuclear units of edge-sharing ‘4+1’ {CuO₃N₂} square pyramids linked through the dipodal {HO₃PC₁₀H₆CO₂}²⁻ ligands.